Aims. Prior cost-effectiveness analyses on osseointegrated prosthesis for transfemoral unilateral amputees have analyzed outcomes in non-USA countries using generic quality of life instruments, which may not be appropriate when evaluating disease-specific quality of life. These prior analyses have also focused only on patients who had failed a socket-based prosthesis. The aim of the current study is to use a disease-specific quality of life instrument, which can more accurately reflect a patient’s quality of life with this condition in order to evaluate cost-effectiveness, examining both treatment-naïve and socket refractory patients. Methods. Lifetime Markov models were developed evaluating active healthy middle-aged male amputees. Costs of the prostheses, associated complications, use/non-use, and annual costs of arthroplasty parts and service for both a socket and osseointegrated (OPRA) prosthesis were included. Effectiveness was evaluated using the questionnaire for persons with a transfemoral amputation (Q-TFA) until death. All costs and Q-TFA were discounted at 3% annually. Sensitivity analyses on those cost variables which affected a change in treatment (OPRA to socket, or socket to OPRA) were evaluated to determine threshold values. Incremental cost-effectiveness ratios (ICERs) were calculated. Results. For treatment-naïve patients, the lifetime ICER for OPRA was $279/quality-adjusted life-year (QALY). For treatment-refractory patients the ICER was $273/QALY. In sensitivity analysis, the variable thresholds that would affect a change in the course of treatment based on cost (from socket to OPRA), included the following for the treatment-naïve group: yearly replacement components for socket > $8,511; cost yearly replacement parts OPRA < $1,758; and for treatment-refractory group: yearly replacement component for socket of > $12,467. Conclusion. The use of the OPRA prosthesis in physically active transfemoral amputees should be considered as a cost-effective alternative in both treatment-naïve and treatment-refractory socket prosthesis patients. Disease-specific quality of life assessments such as Q-TFA are more sensitive when evaluating cost-effectiveness. Cite this article: Bone Jt Open 2024;5(3):218–226

Aims. Safety concerns surrounding osseointegration are a significant barrier to replacing socket prosthesis as the standard of care following limb amputation. While implanted osseointegrated prostheses traditionally occur in two stages, a one-stage approach has emerged. Currently, there is no existing comparison of the outcomes of these different approaches. To address safety concerns, this study sought to determine whether a one-stage osseointegration procedure is associated with fewer adverse events than the two-staged approach. Methods. A comprehensive electronic search and quantitative data analysis from eligible studies were performed. Inclusion criteria were adults with a limb amputation managed with a one- or two-stage osseointegration procedure with follow-up reporting of complications. Results. A total of 19 studies were included: four one-stage, 14 two-stage, and one article with both one- and two-stage groups. Superficial infection was the most common complication (one-stage: 38% vs two-stage: 52%). There was a notable difference in the incidence of osteomyelitis (one-stage: nil vs two-stage: 10%) and implant failure (one-stage: 1% vs two-stage: 9%). Fracture incidence was equivocal (one-stage: 13% vs two-stage: 12%), and comparison of soft-tissue, stoma, and mechanical related complications was not possible. Conclusion. This review suggests that the one-stage approach is favourable compared to the two-stage, because the incidence of complications was slightly lower in the one-stage cohort, with a pertinent difference in the incidence of osteomyelitis and implant failure. Cite this article: Bone Jt Open 2023;4(7):539–550

Introduction. Clione Anchored Replacement Prosthesis (CARP-H system) is a novel femoral implant for cementless fixation at the metaphysis of the proximal femur and preservation of cancellous bone of the femoral diaphysis is expected (Fig.1). We developed CARP-H system and started to use the prosthesis after the approval by Pharmaceuticals and Medical Devices Agency in 2012. This study examines the efficacy and short-term outcome of CARP-H system in a series of patients undergoing total hip arthroplasty (THA) or bipolar hemi-arthroplasty (BHA). Patients and Methods. Seventeen patients (17 hips) of osteonecrosis of the femoral head (ON) or osteoarthritis of the hip (OA) were included. The diagnoses were OA in 10 patients, and ON in 7 patients. The mean age at surgery was 55 years (35–62 years). The mean follow-up was 12 months (6–19 months). THA using CARP-H system was performed in 11 hips and BHA in 6 hips. Results. The mean clinical score with the Merle d'Aubigne and Postel system was improved from 8 points preoperatively to 16 points at follow-up. No complications such as infection, dislocation, intraoperative fracture, or pulmonary infarction were identified. No radiolucent line around the prosthesis was observed postoperatively. Discussion and Conclusion. We used to perform THA using the thrust plate hip prosthesis (TPP) which is an outstanding prosthesis for young patients in terms of bone preservation and biological fixation. Our mid- or long-term outcome of TPP was satisfactory provided the indication was appropriate. However, TPP has been kicked out in our country since 2006. The structural concept of CARP-H system is derived from TPP, and the design of the prosthesis is modified in order to adapt to Japanese patients. CARP-H system could be a beneficial prosthesis from the viewpoint of bone-preservation at the proximal femur

Aims. The aim of this study was to evaluate medium- to long-term outcomes and complications of the Stanmore Modular Individualised Lower Extremity System (SMILES) rotating hinge implant in revision total knee arthroplasty (rTKA) at a tertiary unit. It is hypothesized that this fully cemented construct leads to satisfactory clinical outcomes. Methods. A retrospective consecutive study of all patients who underwent a rTKA using the fully cemented SMILES rotating hinge prosthesis between 2005 to 2018. Outcome measures included aseptic loosening, reoperations, revision for any cause, complications, and survivorship. Patients and implant survivorship data were identified through both prospectively collected local hospital electronic databases and linked data from the National Joint Registry/NHS Personal Demographic Service. Kaplan-Meier survival analysis was used at ten years. Results. Overall, 69 consecutive patients (69 knees) were included with a median age of 78 years (interquartile range 69 to 84), and there were 46 females (66.7%). Indications were septic revisions in 26 (37.7%), and aseptic aetiology in the remining 43 (62.3%). The mean follow-up was 9.7 years (4 to 18), and the overall complication was rate was 7.24%, all with patellofemoral complications. Failure rate with ‘any cause revision’ was 5.8%. There was one case of aseptic loosening of the femoral component. At ten years, 17/69 patients (24.63%) had died, and implant survivorship was 92.2%. Conclusion. In our experience, the SMILES rotating hinge prosthesis achieves satisfactory long-term outcomes with ten-year implant survivorship of 92.2% and a patellofemoral complication rate of 7.24%. Cite this article: Bone Jt Open 2023;4(10):776–781

Aims. The aim of this study was to identify variables associated with time to revision, demographic details associated with revision indication, and type of prosthesis employed, and to describe the survival of hinge knee arthroplasty (HKA) when used for first-time knee revision surgery and factors that were associated with re-revision. Methods. Patient demographic details, BMI, American Society of Anesthesiologists (ASA) grade, indication for revision, surgical approach, surgeon grade, implant type (fixed and rotating), time of revision from primary implantation, and re-revision if undertaken were obtained from the National Joint Registry data for England, Wales, Northern Ireland, and the Isle of Man over an 18-year period (2003 to 2021). Results. There were 3,855 patient episodes analyzed with a median age of 73 years (interquartile range (IQR) 66 to 80), and the majority were female (n = 2,480, 64.3%). The median time to revision from primary knee arthroplasty was 1,219 days (IQR 579 to 2,422). Younger age (p < 0.001), decreasing ASA grade (p < 0.001), and indications for revision of sepsis (p < 0.001), unexplained pain (p < 0.001), non-polyethylene wear (p < 0.001), and malalignment (p < 0.001) were all associated with an earlier time to revision from primary implantation. The median follow-up was 4.56 years (range 0.00 to 17.52), during which there were 410 re-revisions. The overall unadjusted probability of re-revision for all revision HKAs at one, five, and ten years after surgery were 2.7% (95% confidence interval (CI) 2.2 to 3.3), 10.7% (95% CI 9.6 to 11.9), and 16.2% (95% CI 14.5 to 17.9), respectively. Male sex (p < 0.001), younger age (p < 0.001), revision for septic indications (p < 0.001) or implant fracture (p = 0.010), a fixed hinge (p < 0.001), or surgery performed by a non-consultant grade (p = 0.023) were independently associated with an increased risk of re-revision. Conclusion. There were several factors associated with time to first revision. The re-revision rate was 16.2% at ten years; however, the risk factors associated with an increased risk of re-revision could be used to counsel patients regarding their outcome. Cite this article: Bone Joint J 2023;105-B(1):47–55

Introduction: Design of the prosthesis is an important factor in the successful outcome and longevity of total hip replacement. The purpose of the present study is to evaluate the minimum six-year results of primary total hip replacement using LX cemented prosthesis. Methods: We prospectively studied 177 patients (60 male and 117 female) who underwent 197 hip replacements, between 1996 and 1999, using LX cemented prosthesis comprising a femoral component with cylindrical cross section of the stem and an acetabular component of ultrahigh molecular weight polyethylene. The average follow up was 7.3 years (6.1–9.6years). Clinical (Harris Hip Score) and radiological assessments (Barrack’s grading of cementation, subsidence, debonding, radiolucent lines and osteolysis) were performed. Results: The average Harris Hip Score is 85.53 (28–99) compared to the preoperative score of 59.28. 28 cases (14.2%) developed progressive radiolucent lines around the stem. Sinking and debonding of the stem was noted in 18 cases (9.1%). 15 hips (7.6%) have dislocated and 11 were recurrent dislocations. Revision hip replacement was carried out in 12 cases (6%) for subsidence and debonding of stem, cement fracture and recurrent dislocation. The femoral stem components were found to be loose at the time of surgery. Discussion: We believe that design of the prosthesis is an important factor in the high incidence of subsidence and debonding of the femoral stem. Both the geometry (cylindrical shape) and the rough surface finish (Ra value 100 microinches) were responsible for the pattern of progressive loosening. Lack of progressive increase in the offset with increase in the size of femoral component from 1 to 2 is one of the factors which contributed to high incidence of dislocation

Purpose of the study: This retrospective analysis compared surgical treatments of femoral neck fractures in patients aged over 80 years. Material and methods: Two hundred femoral neck fractures (Garden 3 and 4) were treated in three different manners: total prosthesis with a retaining cup (74 patients), intermediary prosthesis (58 patients), and osteosynthesis (68 patients). Indications were the same, but the periods of treatment were successive. Study variables were: mortality, number of revisions, duration of hospital stay, discharge to home or rehabilitation center, cost per hospital day. Follow-up was at least two years. The chi-square test was applied with p< 0.05. Results: Mortality was similar for the three groups: eight deaths during stay in orthopedic unit (4%), three after total prosthesis (4%), three after osteosynthesis (5%) and two after intermediary prosthesis (3%). The difference was nonsignificant (p=0.24). Among the total prostheses, five dislocations (6.7%) required anesthesia despite the retaining cup. The rate of dislocation was 12% for intermediary prostheses and to avoid recurrence four revisions were needed to totalize an intermediary prosthesis with a retaining cup. Among the osteosynthesis cases, the rate of revision was 25%; transformation to a total prosthesis was necessary for 17% and material removal with resection of the head and neck was necessary in 8%. One total prosthesis and one intermediary prosthesis had to be removed because of infection. Resection of the head and neck for infection also occurred in one patient with an intermediary prosthesis. The rate of revision for an orthopedic problem was significantly less (p< 0.01) in the total prosthesis group. At last follow-up, or before death, patients with a total prosthesis were more independent and returned to their home significantly more often than patients treated with osteosynthesis. The economic cost of these interventions were not significantly different, the cost of the implant being insignificant compared with the cost of hospitalization and reeducation of this very elderly population. Discussion: Total hip arthroplasty is a recognized treatment for painful degenerative hip disease. Historically, the total prosthesis was not considered as a first-intention treatment for fractures of the femoral neck in elderly subjects due to the risk of intraoperative blood loss, the risk of infection, and the risk of dislocation if a hip stabilization mechanism was not applied. This study demonstrated that, in light of the complications observed with the other methods, progress in anesthesia and use of implants avoiding dislocation can be proposed as first-intention treatment for total prosthesis patients who suffer a fracture of the femoral neck

Introduction. Post-meniscectomy syndrome is broadly characterised by intractable pain following the partial or total removal of a meniscus. There is a large treatment gap between the first knee pain after meniscectomy and the eligibility for a TKA. Hence, there is a strong unmet need for a solution that will relieve this post-meniscectomy pain. Goal of this first-in-man study was to evaluate the safety and performance of an anatomically shaped artificial medial meniscus prosthesis and the accompanying surgical technique. Methods. A first-in-man, prospective, multi-centre, single arm clinical investigation was intended to be performed on 18 post-medial meniscectomy syndrome patients with limited underlying cartilage damage (Kellgren Lawrence scale 0–3) in the medial compartment and having a normal lateral compartment. Eventually 5 patients received a polycarbonate urethane mediale meniscus prosthesis (Trammpolin® medial meniscus prosthesis; ATRO Medical B.V., the Netherlands) which was clicked onto two titanium screws fixated at the native horn attachments on the tibia. PROMs were collected at baseline and at 6 weeks, 3, 6, 12 and 24 months following the intervention including X-rays at 6, 12 and 24 Months. MRI scans were repeated after 12 and 24 months. Results. The surgical technique to select the appropriately sized implant and correct positioning of the fixation screws and meniscus prosthesis onto the tibia was demonstrated feasible and reproducible. The surgeries showed that in particular the positioning of the posterior screw is crucial for correct positioning of the prosthesis. Inclusion stopped after 5 patients, who reached the 6 months evaluation. The PROMs did not improve in the first 6 months after surgery. All patients reported knee joint stiffness and slight effusion in their knee at 6 months follow-up. In case of symptomatic patients an evaluation of the device position and integrity was performed by MRI. In three patients the implants were removed because of implant failure and in one patient the implant was removed because of persistent pain and extension deficit. At present one patient has the implant still in situ. The explantations of the implants demonstrated no articular cartilage damage and the fixation screws were securely anchored. Discussion. This is the first clinical study with an artificial meniscus-like prosthesis. Except one, all implants were removed due to implant breakage or discomfort of the patient. Analysis of the torn implants showed fatigue failure resulting from the lack of loadsharing between implant and cartilage: the implant was too stiff and carried all the load in the medial compartment of the knee. Furthermore, the fixation with screws seemed too rigid which restricted the motion of the posterior horn. Based on previous in vitro and animal experiments, we expected more creep of the material and more motion on the screw fixation. Conclusion. This first-in-man clinical study demonstrates that the investigated device design is not safe and did not perform as expected. Therefore, modification of the meniscus prosthesis design and fixation technique is required to allow for more motion of the meniscus prosthesis during knee joint movement

Aims. The Mathys Affinis Short is the most frequently used stemless total shoulder prosthesis in the UK. The purpose of this prospective cohort study is to report the survivorship, clinical, and radiological outcomes of the first independent series of the Affinis Short prosthesis. Methods. From January 2011 to January 2019, a total of 141 Affinis Short prostheses were implanted in 127 patients by a single surgeon. Mean age at time of surgery was 68 (44 to 89). Minimum one year and maximum eight year follow-up (mean 3.7 years) was analyzed using the Oxford Shoulder Score (OSS) at latest follow-up. Kaplan-Meier survivorship analysis was performed with implant revision as the endpoint. Most recently performed radiographs were reviewed for component radiolucent lines (RLLs) and proximal humeral migration. Results. Five shoulders underwent revision surgery (3.5%); three for rotator cuff failure, one for infection, and one for component malposition. Survivorship of the implant was 95.4% (95% confidence interval 90.1% to 97.9%) at five and nine years. Mean OSS improved significantly compared to preoperative values from 19.0 (1 to 35) to 43.3 (7 to 48) (p < 0.001). Radiological analysis was undertaken for 99 shoulders. This revealed humeral RLLs in one case (1%), glenoid RLLs in 15 cases (15.2%), and radiological rotator cuff failure in 22 cases (22.2%). Conclusion. This prospective cohort study shows encouraging short- to mid-term survivorship and clinical and radiological results for the Mathys Affinis Short, Short Stem Total Shoulder Prosthesis. Level of Evidence: IV. Cite this article: Bone Jt Open 2021;2(1):58–65

Background. The literature on the outcome of revision total ankle arthroplasty (TAA) remains limited. We aim to report the clinical and radiological outcomes of revision TAA at a high-volume centre in the UK. Methods. Retrospective review of 28 patients that underwent 29 revision TAA procedures using INBONE II prosthesis. Demographic, radiological, and patient reported outcome measures data were analysed. Results. The mean (range) duration from primary TAA to revision was 87.5 (16–223) months. The main indication for the revision was aseptic loosening of the primary TAA (82.8%). Additional procedures were required in 75.9% of patients. At mean (range) follow-up of 40 (24- 60) months, the infection, re-operation, and implant survival rates were 6.9%, 6.9% and 96.5% respectively. A significant postoperative improvement in the component alignment radiographic measures was observed. Osteolysis, subsidence, loosening and heterotopic ossification rates were comparable to other reports and did not influence the clinical outcome. A significant improvement was observed in the MOXFQ (all domains) and the EQ-5D (three domains) at 24 months postoperatively. Conclusions. Revision TAA using INBONE II was associated with good short-term survival and improvement in the postoperative scores at 2 years. Maintenance of the postoperatively improved alignment was documented at follow up. The relatively high survival rate in this series supports the notion that revision TAA is a satisfactory option for failed primary TAA

A common location for radius fracture is the proximal radial head. With the arm in neutral position, the fracture usually happens in the anterolateral quadrant (Lacheta et al., 2019). If traditional surgeries are not enough to induce bone stabilization and vascularization, or the fracture can be defined grade III or grade IV (Mason classification), a radial head prosthesis can be the optimal compromise between bone saving and recovering the “terrible triad”. A commercially available design of radial head prosthesis such as Antea (Adler Ortho, Milan, Italy) is characterized by flexibility in selecting the best matching size for patients and induced osteointegration thanks to the Ti-Por. ®. radial stem realized by 3D printing with laser technique (Figure 1). As demonstrated, Ti-Por. ®. push-out resistance increased 45% between 8 −12 weeks after implantation, hence confirming the ideal bone-osteointegration. Additional features of Antea are: bipolarity, modularity, TiN coating, radiolucency, hypoallergenic, 10° self-aligning. The osteointegration is of paramount importance for radius, in fact the literature is unfortunately reporting several clinical cases for which the fracture of the prosthesis happened after bone-resorption. Even if related to an uncommon activity, the combination of mechanical resistance provided by the prosthesis and the stabilization due to the osteointegration should cover also accidental movements. Based upon Lacheta et al. (2019), after axial compression-load until radii failure, all native specimens survived a compression-load of 500N, while the failure happened for a mean compression force of 2560N. The aim of this research study was to test the mechanical resistance of a radial head prosthesis obtained by 3D printing. In detail, a finite element analysis (FEA) was used to understand the mechanical resistance of the core of the prosthesis and the potential bone fracture induced in the radius with simulated bone- resorption (Figure 2a). The critical level was estimated at the height for which the thickness of the core is the minimum (Figure 2b). Considered boundary conditions:. - Full-length prosthesis plus radius out of the cement block equal to 60mm (Figure 2a);. - Bone inside the cement equal to 60mm (Figure 2b);. - Load inclined 10° epiphysiary component (Figure 2c);. - Radius with physiological or osteoporotic bone conditions;. - Load (concentrated in the sphere simulating full transmission from the articulation) of 500N or 1300N or 2560N. Figure 3 shows the results in terms of maximum stress on the core of the prosthesis and the risk of fracture (Schileo et al., 2008). According to the obtained results, the radial head prosthesis shows promising mechanical resistance despite of the simulated bone-resorption for all applied loads except for 2560N. The estimated mechanical limit for the material in use is 200MPa. The risk of fracture is in agreement with the experimental findings (Lacheta et al. (2019)), in fact bone starts to fail for the minimum reported failure load, but only for osteoporotic conditions. The presented FEA aimed at investigating the behavior of a femoral head prostheses made by 3D printing with simulated bone-resorption. The prosthesis shows to be a skilled solution even during accidental loads. For any figures or tables, please contact the authors directly

Constrained implants with intra-medullary fixation are expedient for complex TKA. Constraint is associated with loosening, but can correction of deformity mitigate risk of loosening?. Primary TKA's with a non-linked constrained prosthesis from 2010-2018 were identified. Indications were ligamentous instability or intra-medullary fixation to bypass stress risers. All included fully cemented 30mm stem extensions on tibia and femur. If soft tissue stability was achieved, a posterior stabilized (PS) tibial insert was selected. Pre and post TKA full length radiographs showed. i. hip-knee-ankle angles (HKAA). ii. Kennedy Zone (KZ) where hip to ankle vector crosses knee joint. 77 TKA's in 68 patients, average age 69.3 years (41-89.5) with OA (65%) post-trauma (24.5%) and inflammatory arthropathy (10.5%). Pre-op radiographs (62 knees) showed varus in 37.0%. (HKAA: 4. o. -29. o. ), valgus in 59.6% (HKAA range 8. o. -41. o. ) and 2 knees in neutral. 13 cases deceased within 2 years were excluded. Six with 2 year follow up pending have not been revised. Mean follow-up is 6.1 yrs (2.4-11.9yrs). Long post-op radiographs showed 34 (57.6%) in central KZ (HKKA 180. o. +/- 2. o. ). . Thirteen (22.0%) were in mechanical varus (HKAA 3. o. -15. o. ) and 12 (20.3%) in mechanical valgus: HKAA (171. o. -178. o. ). Three failed with infection; 2 after ORIF and one with BMI>50. The greatest post op varus suffered peri-prosthetic fracture. There was no aseptic loosening or instability. Only full-length radiographs accurately measure alignment and very few similar studies exist. No cases failed by loosening or instability, but PPF followed persistent malalignment. Infection complicated prior ORIF and elevated BMI. This does not endorse indiscriminate use of mechanically constrained knee prostheses. Lower demand patients with complex arthropathy, especially severe deformity, benefit from fully cemented, non-linked constrained prostheses, with intra-medullary fixation. Hinges are not necessarily indicated, and rotational constraint does not lead to loosening

Prosthetic joint infections represent complications connected to the implantation of biomedical devices, they have high incidence, interfere with osseointegration, and lead to a high societal burden. The microbial biofilm, which is a complex structure of microbial cells firmly attached to a surface, is one of the main issues causing infections. Biofilm- forming bacteria are acquiring more and more resistances to common clinical treatments due to the abuse of antibiotics administration. Therefore, there is increasing need to develop alternative methods exerting antibacterial activities against multidrug-resistant biofilm-forming bacteria. In this context, metal-based coatings with antimicrobial activities have been investigated and are currently used in the clinical practice. However, traditional coatings exhibit some drawbacks related to the insufficient adhesion to the substrate, scarce uniformity and scarce control over the toxic metal release reducing their efficacy. Here, we propose the use of antimicrobial silver-based nanostructured thin films to discourage bacterial infections. Coatings are obtained by Ionized Jet Deposition, a plasma-assisted technique that permits to manufacture films of submicrometric thickness having a nanostructured surface texture, allow tuning silver release, and avoid delamination. To mitigate interference with osseointegration, here silver composites with bone apatite and hydroxyapatite were explored. The antibacterial efficacy of silver films was tested in vitro against gram- positive and gram-negative species to determine the optimal coatings characteristics by assessing reduction of bacterial viability, adhesion to substrate, and biofilm formation. Efficacy was tested in an in vivo rabbit model, using a multidrug-resistant strain of Staphylococcus aureus showing significant reduction of the bacterial load on the silver prosthesis both when coated with the metal only (>99% reduction) and when in combination with bone apatite (>86% reduction). These studies indicate that IJD films are highly tunable and can be a promising route to overcome the main challenges in orthopedic prostheses

Aim. Due to medical and organizational factors, it occurs in everyday practice that spacers are left in place longer than originally planned during a two-stage prosthesis exchange in the case of prosthetic joint infections. Patients are severely restricted in their mobility and, after initial antibiotic administration, the spacer itself only acts as a foreign body. The aim of this study is to analyze whether the duration of the spacer in situ has an influence on the long-term success of treatment and mortality. Method. We retrospectively studied all 204 two-stage prosthesis replacements of the hip and knee from 2012 to 2016 with a minimum follow-up of two years at an arthroplasty center with 3 main surgeons. The duration of the spacer interval was divided into two groups. Patients replanted within ten weeks (as is standard in multiple algorithms) after systemic antibiotic treatment were assigned to the ‘Regular Spacer Interval (< 70 days)’ group. If the spacer interval was longer, they were assigned to the ‘Long Spacer Interval (≥ 70 days)’ group. Results. Patients were on average 67.69 years old (SD 12.3). The mean duration of the spacer-interval was 100.9 days (range: 423.0; SD, 60.0). In 62 patients reimplantation could be performed within 70 days after explantation, in 142 patients this took longer (max. 438 days). In 26 patients, the spacer had to be changed at least once during this period (11 patients in the hip group, and 15 patients in the knee group). In the remaining cases, other medical or organizational reasons delayed replantation. Both groups were comparable concerning Charlson Comorbity Index, age, number of previous surgeries and laboratory infection markers. There was no statistically significant influence of the duration of the spacer interval on the infection free survival (n=204, p=0.32). There was also no influence on mortality (n=204, p=0.35) and aseptic implant failure (n=204, p=0.15). Conclusions. The timely replantation of a knee or hip prosthesis seems to be reasonable in general because the patients are strongly limited in their mobility and daily activities by the spacer. However, there does not seem to be a negative influence on infection eradication and survival due to a long spacer interval

The place of the myo-electric prosthesis in below-elbow amputees has been reviewed. Forty-three patients were seen and all possessed both a myo-electric prosthesis and a standard artificial limb. Nearly half the patients used the newer device almost all the time at work and many of these wore it for the majority of their waking hours. Its use at work was mainly related to the patient's type of job and here in turn there was concern about damaging the device. It is suggested that acceptance would be further increased if greater attention were paid to the durability of the arm and its glove. Criteria for prescription and future developments are discussed

Purpose: A spacer can be used for two-phase replacement of an infected total hip prosthesis. The goal is to facilitate reimplantation by avoiding soft tissue retraction. Several types of spacers can be used. We searched for a spacer which avoids wear debris due to methacrylate friction against bone, delivers a local antibiotic, is easily removed, and does not worsen bone damage. Since 1995, we have used a Charnley Kerboull type prosthesis as a spacer. The purpose of the present study was to 1) verify the absence of spacer-related complications, 2) assess outcome in terms of cure of infection and improved function. Material and methods: We used 14 articulated spacers for two-phasee prosthesis replacement in nine men and five women, mean age 64 years. Erythrocyte sedimentation rate was 32 and C-reactive protein was 17. The mean Postel-Merle d’Aubigné (PMA) score was 3+5+2. All patients were reviewed at a minimum 37 months follow-up. Technique: The approach was generally a digastric trochanterotomy, associated with a more or less extensive femoral procedure (depending on the length of the plug to remove) to achieve removal of all implants and cement. A small-size polyethylene cup was inserted with cement delivering at least one antibiotic on a Surgicel bed to facilitate later extraction. A long small-diameter femoral stem was then inserted (bridging the femoral window) and blocked with cement, also on a Surgicel bed. Partial then total weight bearing was authorised between the phases. Results: There were no dislocations. All patients achieved total weight bearing between the two phases. The same germ identified at the first operation was also identified at the second in two patients, requiring prolonged antibiotic therapy. There was one septic failure, in a different patient. The mean PMA score was 5.7+5.8+5.2. Conclusion: This technique avoids methacrylate wear induced by classical spacers and does not modify polymorphonuclear chemotactism, facilitating the efficacy of medical treatment. Patient comfort is also improved between the two phases and muscle atrophy, which could compromise long-term function, is avoided

Previous scientific studies have highlighted how coupling is an important element affecting total hip arthroplasty's survival. This study aims to evaluate whether metal-on-metal (MOM) coupling could be a statistically significant risk factor. The data from the regional joint registry (Registro dell'Impiantologia Protesica Ortopedica, RIPO) was used for analysis. The data collection accuracy of this registry was 97.2% in 2017. We retrospective evaluate all MOM total hip arthroplasties (THAs) implanted in our department between January 01st 2000 and December 31st 2011. We used a control group composed by all other prosthesis implanted in our Department in the same time lapse. We registered 660 MOM THAs. Mean age of patients was 66.9 years. 603 patients have a >36mm head, while 78 a <36 mm one. Neck modularity was present in half of patients. 676 implants were cementless. We registered 69 revisions, especially due to aseptic mobilization (16 THAs), implant breakage (9 THAs) and periprosthetic fracture (6 THAs). The MOM THAs overall Kaplan-Meier survival rate was 87.2 at 15 years, and the difference between MOM THAs and other implants two curves is statistically significant (p<0.05). Male sex is a significant risk factors. Further evaluations are in progress to establish the presence of any additional risk factors. We think weight and/or BMI may be included in this category. Our study confirms the data currently present in the literature regarding a lower survival of metal-on-metal hip prostheses. The male sex is a statistically significant risk factor (p<0.05), while age, head size and modularity of the prosthetic neck are not statistically significant (p>0.05). Any new finds will be presented at the congress venue

Coronoid fractures account for 2 to 15% of the cases with elbow dislocations and usually occur as part of complex injuries. Comminuted fractures and non-unions necessitate coronoid fixation, reconstruction or replacement. The aim of this biomechanical study was to compare the axial stability achieved via an individualized 3D printed prosthesis with curved cemented intramedullary stem to both radial head grafted reconstruction and coronoid fixation with 2 screws. It was hypothesized that the prosthetic replacement will provide superior stability over the grafted reconstruction and screw fixation. Following CT scanning, 18 human cadaveric proximal ulnas were osteotomized at 40% of the coronoid height and randomized to 3 groups (n = 6). The specimens in Group 1 were treated with an individually designed 3D printed stainless steel coronoid prosthesis with curved cemented intramedullary stem, individually designed based on the contralateral coronoid scan. The ulnas in Group 2 were reconstructed with an ipsilateral radial head autograft fixed with two anteroposterior screws, whereas the osteotomized coronoids in Group 3 were fixed in situ with two anteroposterior screws. All specimens were biomechanically tested under ramped quasi-static axial loading to failure at a rate of 10 mm/min. Construct stiffness and failure load were calculated. Statistical analysis was performed at a level of significance set at 0.05. Prosthetic treatment (Group 1) resulted in significantly higher stiffness and failure load compared to both radial head autograft reconstruction (Group 2) and coronoid screw fixation, p ≤ 0.002. Stiffness and failure load did not reveal any significant differences between Group 2 and Group 3, p ≥ 0.846. In cases of coronoid deficiency, replacement of the coronoid process with an anatomically shaped individually designed 3D printed prosthesis with a curved cemented intramedullary stem seems to be an effective method to restore the buttress function of the coronoid under axial loading. This method provides superior stability over both radial head graft reconstruction and coronoid screw fixation, while achieving anatomical articular congruity. Therefore, better load distribution with less stress at the bone-implant interface can be anticipated. In the clinical practice, implementation of this prosthesis type could allow for early patient mobilization with better short- and long-term treatment outcomes and may be beneficial for patients with irreparable comminuted coronoid fractures, severe arthritic changes or non-unions

Revision total hip arthroplasty (rTHA) in the presence of femoral defects can be technically challenging. Reconstruction with long stems is widely accepted as the standard. However long stems can be difficult to insert and can compromise distal bone stock for future revisions. The aims of this study were to identify whether there was a difference in survival and outcomes following rTHA using a long versus standard or short femoral stem. A comprehensive systematic review was performed according to PRISMA guidelines using the MEDLINE, EMBASE, Chochrane Library and Web of Science databases. Inclusion criteria were (i) adult patients >18 years; (ii) randomised controlled trials, joint registry, or cohort studies; (iii) single or staged rTHA for Paprosky 1–3B femoral defects. Exclusion criteria were (i) mixed reporting without subgroup analysis for revision stem length; (ii) ex-vivo studies. Screening for eligibility and assessment of studies was performed by the authors. Out of 341 records, 9 studies met criteria for analysis (including 1 study utilising joint registry data and 1 randomised controlled trial). Across studies there were 3102 rTHAs performed in 2982 patients with a mean age of 67.4 years and a male: female ratio of 0.93. Revision prostheses were long-stemmed in 1727 cases and short or standard in 1375 cases with a mean follow up of 5 years (range, 0-15 years). On subgroup analysis the use of a long cemented stem compared to a long cementless prosthesis was associated with fewer complications and periprosthetic fracture in older patients. Survivorship was 95% with short stems compared to 84% with long stems at 5 years. Moderate quality evidence suggests that in rTHA with Paprosky type 1-3B femoral defects, the use of a short or standard stem can achieve comparable outcomes to long stems with fewer significant complications and revisions. Using a shorter stem may yield a more straightforward surgical technique and can preserve distal bone stock for future revision

Aims

The aim of this study was to compare the biomechanical models of two frequently used techniques for reconstructing severe acetabular defects with pelvic discontinuity in revision total hip arthroplasty (THA) – the Trabecular Metal Acetabular Revision System (TMARS) and custom triflange acetabular components (CTACs) – using virtual modelling.

The management of femoral bone loss is challenging during revision hip arthroplasty. In patients with Paprosky grade IIIB and IV defects, obtaining fixation and rotational stability using traditional surgical constructs is difficult. The use of a custom-made internal proximal femoral replacement prostheses has been proposed as a solution in patients, with severe femoral bone stock loss. However, there is a paucity in the literature on their use and long-term outcomes. We report on the clinical and radiological results of our cohort. We retrospectively reviewed all patients who underwent internal proximal femoral replacement for revision hip arthroplasty between April 1996 and April 2019. All patients had at least 2 years of follow-up time. 160 patients underwent limb salvage at our institution using internal proximal femoral replacement. The mean follow-up was 79.7 months (S.D 41.3). Indications for revision included periprosthetic fractures, aseptic loosening, and deep infection. The mean Oxford hip score increased from 13.8 (0–22) to 31.5 (18–43) (paired t-test, p < 0.001). Kaplan-Meier prosthesis survival analysis with revision as the endpoint was 87% at 5 years. None required revision of the femoral stem. There were four dislocations (5%) and there was failure to eradicate the deep infection in four. This technique allows instant distal fixation, allowing for early mobilisation. Long-term clinical and radiological outcomes are encouraging and the complication rates are acceptable for this patient group

Purpose

The purpose of this study was to elucidate kinematic change according to the implant's specific femoral rotation by using orthosensor (Verasense) implant with three degrees external rotation of femoral rotation rebuilt (Genesis-II) and traditional TKA implant without rebuilt of the femoral rotation (Anthem).

Purpose: The purpose of this work was to evaluate the quality of cemented humeral stem fixation. We analysed the incidence and influence of humeral lucent lines and loosening after implantation of a shoulder prosthesis as a function of aetiology (fracture versus scapular osteoarthritis) and glenoid status (total versus partial humeral prosthesis). Material and methods: This retrospective series included 1842 first-intention shoulder prostheses reviewed at mean five years (2–10). We selected patients whose initial diagnosis was fracture of the superior portion of the humerus (n=300) and centred osteoarthritis (n=767). All stems implanted for fracture were cemented. For osteoarthritis, there were 610 total prostheses and 157 simple humeral prostheses: 752 stems were cemented and 15 were implanted without cement. The Constant score and radiographic results (AP and lateral view at least) were noted. Results: For cemented stems, the incidence of radiographic lucent lines and loosening was significantly higher in fractures (40% and 10% respectively) than in centred osteoarthritis (14% and 1%). Lucency and loosening did not influence functional outcome in patients with centred osteoarthritis but had a significantly negative effect on final outcome in fractures. For fractures, the incidence of lucent lines was correlated with migration of the tubercles. For osteoarthritis, there was no difference between total and partial prostheses in terms of loosening, but the functional outcome was significantly better with total prostheses. Conclusion: Fixation of the humeral implant with cement remains the gold standard for shoulder prostheses implanted for centred osteoarthritis. However, cement fixation yields disappointing results for fractures: defective fixation of the humeral stem is correlated with migration of the tubercles. For osteoarthritis, there are not more lucent lines with a total prosthesis which provides the better functional results

Aim. A significant number of patients undergoing shoulder arthroplasty surgery have C acnes contamination at the end of the primary surgery. The objective of this study is to determine whether patients with C acnes contamination at the end of their primary shoulder surgery have a worse prognosis than those who end up without C. acnes contamination. Method. Prospective study including all patients who underwent a reverse shoulder prosthesis from January 2015 to December 2018. In all of them, 5 to 12 cultures were performed during primary surgery. The patients underwent surgery for shoulder arthritis secondary to rotator cuff tears, acute fracture of the proximal humerus, and sequelae of fracture of the proximal humerus. Exclusion criteria included the existence of previous surgeries on the affected shoulder, the presence of signs of infection, having received infiltrations and / or complementary invasive examinations (Arthro-MRI and Arthro-CT). Follow-up from 2 to 5 years. Functional assessment according to the Constant Functional Scale. All complications were also recorded. Results. 162 patients were included. Of these, 25 had positive cultures for C. acnes at the end of primary shoulder surgery. Average age of 74.8 years. 136 women and 26 men. 75.9% Shoulder arthritis secondary to rotator cuff tears, 13.6% acute fractures and 10.5% sequelae of fractures. There were no differences between patients with C. acnes and those without C. acnes regarding age and indication for surgery. Predominance of men in the group with positive C. acnes (p <0.001). No differences at 2 and 5 years in the Constant functional scale between the two groups (2 years, 59.6 vs 59.2 p 0.870) (5 years, 62.4 vs 59.5 p 0.360). Significant differences regarding the number of complications (p 0.001). Patients without C. acnes had 1 aseptic loosening of the metaglene and patients with C. acnes had 2 infections, 1 dislocation, and 1 revision surgery. Patients with contamination by C. acnes had more comorbidities (p 0.035) than patients without contamination. Conclusions. Patients with C acnes contamination at the end of primary surgery do not have functional differences when compared with patients without contamination at 2 and 5 years, but they have a higher number of complications in the medium term

Introduction. Studies have shown that increased implant conformity in total knee arthroplasty (TKA) has been linked to increased constraint and thus rotational torque at the bone/implant interface. Anterior stabilized (AS) tibial inserts were designed to compensate for excessive AP motion in less-conforming cruciate-retaining (CR) tibial inserts. However, increased constraint may affect implant loading. Therefore, the purpose of this study is to model rotational prosthesis constraint based on implant-specific data and to compare rotational torque and 3D contact forces in implants with CR-lipped and AS tibial inserts during normal gait. Methods. A previously reported knee joint contact model was updated to include rotational torque due to prosthesis constraint (ASTM F1223(14)). Piecewise multiple linear regression with manually selected cutoff points was used to determine estimates of AP force, ML force, and rotation torque as functions of AP displacement, ML displacement, knee external rotation, respectively, and knee flexion angle from standard data. These functions were used to estimate total moment contribution of the prosthesis from measured knee displacement/rotation angles. Estimates were incorporated into the contact model equilibrium equations as needed by the model. As the model parametrically varies muscle activation coefficients to solve for the range of physiologically possible forces at each time point, the reported force/torque values are the mean across all solutions at each time point. Rotational torque and three dimensional contact forces were calculated for 14 informed-consented subjects, five with AS tibial inserts (1/4 m/f, 67±10 years, 29.2±4.4 BMI, 1/4 right/left) and nine with CR-lipped TKRs (2/7 m/f, 64±6 years, 30.6±5.8 BMI, 4/5 right/left). Rotational torque waveforms were compared using statistical nonparametric mapping; 3D contact forces were compared at mean timing of the flexion/extension moment peaks using independent samples t-tests. Results. Waveform analysis of rotational torque found no significant differences between implant types. CR- lipped inserts showed an initial peak internal rotation torque during weight acceptance and continued with a pattern of internal rotation throughout stance. Peak torque for AS inserts also occurred during weight acceptance, but it varied between internal/external rotation torque. Additionally, after weight acceptance, AS subjects showed a pattern of external rotation torque. Mean axial force, medial-lateral shear force, and anterior-posterior shear force waveforms were similarly shaped between implant groups. Flexion and extension moment peaks occurred at 23% and 74% stance on average. There were no significant differences in three-dimensional knee joint contact forces between groups at either time point. Discussion. There were different patterns of rotational torque between groups. Implants with lipped CR inserts tended to undergo internal rotation torques that peaked during weight acceptance. Torque seen in implants with AS inserts was also largest during weight acceptance, but greatly varied between internal and external rotation, before settling in a pattern of external rotation for the remainder of stance. This may be due to constraints added by AS insert geometry. In conclusion, a model of rotational torque due to implant constraints has been developed; increased implant constraint increased the external rotation torque experienced by the implant and may also affect shear forces at the implant surface. For any figures or tables, please contact authors directly

Purpose of the study: The purpose of this study was to compare mid-term results after total shoulder arthroplasty (TSA) versus simple humeral arthroplasty (SHA) for the treatment of primary centered osteoarthritic degeneration of the shoulder joint. Material and methods: The series included 41 Aequalis prostheses (27 TSA, 14 SHA) implanted by the same surgeon. TSA was performed in 21 women and six men, mean age 68.3 years (range 51–78). SHA was performed in nine women and five men, mean age 68.3 years (range 58–83). The glenoid cavity presented concentric wear (type A) in 70% and asymmetric wear (type B) in 30% of patients undergoing TSA. Type A wear was observed in 57% of the patients undergoing SHA and type B (or C) wear in 43% of them. Mean follow-up was 35 months (range 24–49) for TSA and 37 months (24–59) for SHA. The Constant score and the Neer classification were noted. The position of the implants and lucent lines was noted on plain x-rays. Results: For the TSA patients, the mean non-weighted Constant score was 82/100 points (gain of 48 points), anterior elevation was 151° (gain 54°), and active external rotation 44° (gain 29°). For the SHA patients, the mean non-weighted Constant score was 71/100 points (gain 41 points), active anterior elevation 135° (ain 46°), and active external rotation 43° (gain 28°). The Neer classification demonstrated excellent or satisfactory outcome for 93% of the TSA patients and 86% of the SHA patients. TSA was more effective than SHA for pain relief (p=0.045). Periglenoid lucent lines were observed for 63% of the TSA but with no loosening or complication for the glenoid component at last follow-up. Discussion: Compared with a simple humeral prosthesis, total shoulder arthroplasty was more effective for the treatment of primary centered osteoarthritis of the shoulder joint

Aim. Patellofemoral Arthroplasty (PFA) prosthesis with asymmetric trochlear component was introduced as an improvement from existing designs for surgical treatment of symptomatic isolated patellofemoral arthritis. The purpose of this study was to evaluate midterm results in patients who underwent PFA procedure using such prosthesis. Methods. Our study involved a continuous retrospective cohort of patients who underwent PFA using Journey PFJ with asymmetric trochlear component, performed between June 2007 and October 2018 at a non-designer centre. The Patient Reported Outcome Measures and patient satisfaction questionnaires were collected for final evaluation. Results. A total of 128 PFA performed on 96 patients were evaluated. All patients were under regular follow up, and no patient was lost to follow up. Eighteen patients underwent simultaneous bilateral procedures, and 14 patients underwent PFA of the contralateral knee later. Median age at the time of surgery was 59 years (interquartile range 53 – 66 years); the median follow up period was 6 years (interquartile range 2.5 – 7 years). The Oxford Knee Score showed improvement from a median of 18 to 37. There were statistically significant improvements in functional outcome scores. Beverland satisfaction questionnaire revealed that 22.1 % (19/86) were ‘Very happy’ and 39.5% (34/86) were ‘Happy’ following the procedure. Four knees were revised to Total Knee Arthroplasty for reasons not related to the implant. The cumulative survival estimated by the Kaplan-Meier method was 95.2% (95% confidence interval: 90.4%– 99.9%). Conclusion. This series of patients who underwent PFA with the asymmetric trochlear component has shown promising mid-term results with no implant related complications

Aims. The Intraosseous Transcutaneous Amputation Prosthesis (ITAP) may improve quality of life for amputees by avoiding soft-tissue complications associated with socket prostheses and by improving sensory feedback and function. It relies on the formation of a seal between the soft tissues and the implant and currently has a flange with drilled holes to promote dermal attachment. Despite this, infection remains a significant risk. This study explored alternative strategies to enhance soft-tissue integration. Materials and Methods. The effect of ITAP pins with a fully porous titanium alloy flange with interconnected pores on soft-tissue integration was investigated. The flanges were coated with fibronectin-functionalised hydroxyapatite and silver coatings, which have been shown to have an antibacterial effect, while also promoting viable fibroblast growth in vitro. The ITAP pins were implanted along the length of ovine tibias, and histological assessment was undertaken four weeks post-operatively. Results. The porous titanium alloy flange reduced epithelial downgrowth and increased soft-tissue integration compared with the current drilled flange. The addition of coatings did not enhance these effects. Conclusion. These results indicate that a fully porous titanium alloy flange has the potential to increase the soft-tissue seal around ITAP and reduce susceptibility to infection compared with the current design. Cite this article: Bone Joint J 2017;99-B:393–400

The Thompson hemiarthroplasty is a common treatment option for acute neck of femur fractures in the elderly population. Our department noted a significant number of patients returning with thigh pain, radiographic loosening and femoral osteolysis following cemented implantation of the titanium alloy version of the Thompson hemiarthroplasty. We are not aware of any previous reports documenting complications specific to the titanium Thompson implant and a retrospective cohort study was therefore initiated following clinical governance approval.

366 titanium alloy Thompson prostheses were implanted for hip fracture treatment between 2017 and 2020. As of February 2023, 6 of these have been revised at our hospital. 5 were revised for symptomatic femoral osteolysis and 1 presented with an acute periprosthetic fracture. All revised cases were determined to be aseptic. 32 living patients were excluded from recall on compassionate grounds due to permanent nursing home residence. 47 living patients were identified of which 33 attended for xray. 28 deceased and/or nursing home resident patients who had pelvis x-rays in the previous 12 months were also included in the analysis. Including the 6 index hips already revised, a total of 61 hip xrays were analysed, of which 19 hips (31.1%) showed radiographic evidence of femoral osteolysis or loosening.

We conclude that there is a concerning incidence of femoral osteolysis and implant loosening associated with the titanium Thompson implant. We have discontinued use of the implant and reported our experience to the MHRA. We encourage other Scottish Health-Boards who use this implant to consider enhanced follow-up.

Total ankle replacement (TAR) is contraindicated in patients with significant talar collapse due to AVN and in these patients total talus body prosthesis has been proposed to restore ankle joint. To date, five studies have reported implantation of a custom-made talar body in patients with severely damaged talus, showing the limit of short-term damage of tibial and calcaneal thalamic joint surfaces. Four of this kind of implants have been performed. The first two realized with “traditional” technology CAD-CAM has been performed in active patients affected by “missing talus” and now presents a survival follow-up of 15 and 17 years. For the third patient affected by massive talus AVN we designed a 3D printed porous titanium custom talar body prosthesis fixed on the calcaneum and coupled with a TAR, first acquiring high-resolution 3D CT images of the contralateral healthy talus that was “mirroring” obtaining the volume of fractured talus in order to provide the optimal fit. Then the 3D printed implant was manufactured. The fourth concern a TAR septic mobilization with high bone loss of the talus. The “two-stage” reconstruction conducted with the implant of total tibio-talo-calcaneal prosthesis “custom made” built with the same technology 3D, entirely in titanium and using the “trabecular metal” technology for the calcaneous interface. Weightbearing has progressively allowed after 6 weeks. No complications were observed. All the implants are still in place with an overall joint mobility ranging from 40° to 60°. This treatment requires high demanding technical skills and experience with TAR and foot and ankle trauma. The 15 years survival of 2 total talar prosthesis coupled to a TAR manufactured by a CAD-CAM procedure encourages consider this 3D printed custom implant as a new alternative solution for massive AVN and traumatic missing talus in active patients

Aim. In surgeries on patients with advanced ligament instabilities or severe bone defects modern-generation of rotating hinged knee prostheses are one of the main options. The objective of our study is to evaluate the mid-term functional results and complications of several surgeries using this form of prosthesis. Material and Method. The rotating hinged knee prosthesis (RHKP) was applied to 208 knees of 204 patients in primary surgeries between September 2009 and December 2017, the minimum followup was 15 months (mean, 65 months; range, 15–115 months). Of the total number of female patients there were 152 (74.5%), men − 52 (25.5%). The average age of the patients was 64,6 years (from 32 to 85). The main indications for using RHKP were severe varus deformity with flexion contracture in 107 knees (51,4%), severe valgus deformity (from 20 to 50 degrees) in 54 knees (26,0 %), severe ligamentous deficiencies in 24 knees (11,5%) and ankylosis in the flexion position in 23 cases (11,1%). Patients were evaluated clinically (Knee Society score) and radiographically (positions of components, signs of loosening, bone loss). Results. The average Knee Society Knee Scores, and Knee Society Functional Scores were 27, and 18, respectively, before the surgery; and 86, and 77 in the final post-surgery follow-ups. In addition, the average range of motion increased from the pre-operative level of 46 to 104 degrees at the final evaluation. Four patients (2%) had various complications after the surgery : two patients had deep infection, in one case took place fracture of the hinge mechanism and in one - post-operative rupture of the patellar tendon. Conclusions. Primary knee arthroplasty using RKHP can be successful in cases with advanced ligament instability or severe bone defects. Modern-generation of the kinematic rotating-hinge total knee prostheses allow to achieve in difficult primary cases the same consistently good results as commonly used constructions in standard situations

Orthopaedic implants, such as femoral heads, sockets and stems, are manufactured with a high degree of smoothness and very low form error in order to function as low wear bearings. The surfaces are subject to both wear and damage during in vivo use. Articulating surfaces naturally wear during normal use. Aseptic loosening associated with osteolysis and release of wear particles is the main reason for revision of total hip arthroplasty (THA). Damage of femoral heads is well known to increase the wear rate at the articulating surface and is vulnerable to scratching during the maneuver of positioning the femoral component into the acetabulum component either in primary as in revision total hip arthroplasties. The findings emphasize the importance of achieving and maintaining good surface finish of the femoral head component. The author presents a very simple and “zero cost” method of preventing scratching of the femoral head of any kind of total hip prosthesis (ceramic on ceramic, ceramic on poly, metal on metal, metal on poly and even metal on ceramic) when the reduction of the femoral head prosthesis is done inside the new acetabular component with metal, ceramic liner or poly liner with metal back (where the scratching can also occur) as one of the final stages of the surgical procedure which can be crucial to the long survival of the hip prosthesis. A short one minute video on an e-poster will show how this can be done being an easy, reproducible, safe and reliable technique to prevent femoral head scratching

In 2011, approximately 1.6 million total hip arthroplasties (THAs) were conducted in 27 of the 34 member countries in the Organization for Economic Cooperation and Development (OECD) However, approximately 10–15% of patients still require revision surgery every year. Therefore, new technologies are required to increase the life-spam of the prosthesis from the current 10–15 years to at least 20–30 years. Our strategy focuses on surface modification of the bearing materials with a hydrophilic coating to improve their wear behaviour. These coatings are biocompatible, with high swelling capacity and antifouling properties, mimicking the properties of natural cartilage, i.e. wear resistance with permanent hydrated layer that prevents prosthesis damage. Clear beneficial advantages of this coating have been demonstrated in different conditions and different materials, such as UHMWPE, PEEK, CrCo, Stainless steel, ZTA and Alumina. Using routine tribological experiments, the wear for UHMWPE substrate was decreased by 75% against alumina, ZTA and stainless steel. For PEEK-CFR substrate coated, the amount of material lost against ZTA and CrCo was at least 40% lower. Further experiments on hip simulator adding abrasive particles (1-micron sized aluminium particles) during 3 million cycles, on a total of 6 million, showed a wear decreased of around 55% compared to uncoated UHMWPE and XLPE. In conclusion, CIDETEC‘s coating technology is versatile and can be adapted to protect and improve the tribological properties of different types of surfaces used for prosthesis, even in abrasive conditions

Aims. To explore the effect of different types of articulating antibiotic-loaded cement spacers in two-stage revision for chronic hip prosthetic joint infection (PJI). Methods. A retrospective cohort study was performed involving 36 chronic PJI patients treated with different types of articulating antibiotic-loaded cement spacers between January 2014 and December 2017. The incidence of complications and the therapeutic effects of different types of antibiotic-loaded articulating cement spacers were compared. Results. A total of 36 patients with chronic hip PJI were included. Of these, 13 patients were treated with spacers with Kirschner wires as an endoskeleton (group I), ten patients were treated with spacers with a cemented femoral prosthesis as an endoskeleton (group II), and 13 patients were treated with cemented femoral prostheses combined with polyethylene sockets as a spacer (group III). All patients were followed for 12 to 60 months, with a mean follow-up period of 26.44 months (SEM 14.09). Infection was controlled in 34 patients (94.44%), and there were no significant differences in the eradication rate among the three groups (p = 0.705), but the risk of complications related to the spacer in group III was significantly lower than that in groups I and II (p = 0.006). Conclusion. Articulating antibiotic-loaded cement spacers is effective in the treatment of chronic hip PJI, but we must pay attention to the occurrence of spacer fracture and dislocation, which can lead to poor joint function. The risk of spacer-related mechanical complications is low, and better joint function can be achieved when using cemented femoral prostheses combined with polyethylene sockets as spacers. Cite this article: Bone Joint Res 2020;9(8):484–492

Modulus femoral prosthesis is a modular cementless femoral system which consists of 5 degree tapered conical stem made of a titanium alloy with 8 fins of 1mm and modular neck. Modular neck enables to control any ideal stem anteversion as a surgeon prefers. This system is considered to be useful in severe hip deformity, for example developmental dysplasia of the hip (DDH). In this study, clinical and radiographic outcomes of the Modulus femoral prosthesis were evaluated at a mean of 3.6 (2–6) years postoperatively. We assessed the results of 193 primary total hip arthroplasty using a Modulus femoral prosthesis in 169 patients (15 males, 154 females) undergoing surgery between September 2007 and December 2011. The mean age at the time of surgery was 65.6 (31–86) years old. The diagnoses were osteoarthritis (OA) in 178 hips (including 167 hips of DDH), rapidly destructive coxopathy (RDC) in 6 hips, rheumatoid arthritis (RA) in 6 hips, osteonecrosis in 2 hips, and subchondral insufficiency fracture in one hip. Clinical outcomes were assessed using Japan Orthopedic Association (JOA) hip scores and complications. Radiographic assessments were including stem alignment, bone on-growth, cortical hypertrophy, stress shielding and stem subsidence. 43.8 points of the preoperative mean JOA score was significantly improved to 93.1 points postoperatively. In one case intraoperative femoral fracture was occurred. One dislocation had occurred and thigh pain was observed in one hip. No revision surgery was required. In 192 hips of 193 hips (99.5%), stem was implanted in neutral position (within ±2 degrees). Bone on-growth was observed in all cases (94.3% in zone 3; 73.1% in zone 5; 30.6% in zone 2; 22.3% in zone 6). Cortical hypertrophy was observed in 66 hips (34.2%) at zone 3 and 5. Reduction of bone density due to stress shielding was observed (1. st. degree was 58.5%; 2. nd. degree was 29.5%; 3. rd. degree was 11.9%; 4. th. degree was 0%). In 22 cases (11.4%), more than 2mm of stem subsidence was observed, however the subsidence was stopped within 6 months in all cases. Modulus femoral prosthesis showed good clinical results and radiographic findings up to 6 years postoperatively

Aims. The aim of this study was to compare the cost-effectiveness of treatment with an osseointegrated percutaneous (OI-) prosthesis and a socket-suspended (S-) prosthesis for patients with a transfemoral amputation. Patients and Methods. A Markov model was developed to estimate the medical costs and changes in quality-adjusted life-years (QALYs) attributable to treatment of unilateral transfemoral amputation over a projected period of 20 years from a healthcare perspective. Data were collected alongside a prospective clinical study of 51 patients followed for two years. Results. OI-prostheses had an incremental cost per QALY gained of €83 374 compared with S-prostheses. The clinical improvement seen with OI-prostheses was reflected in QALYs gained. Results were most sensitive to the utility value for both treatment arms. The impact of an annual decline in utility values of 1%, 2%, and 3%, for patients with S-prostheses resulted in a cost per QALY gained of €37 020, €24 662, and €18 952, respectively, over 20 years. Conclusion. From a healthcare perspective, treatment with an OI-prosthesis results in improved quality of life at a relatively high cost compared with that for S-prosthesis. When patients treated with S-prostheses had a decline in quality of life over time, the cost per QALY gained by OI-prosthesis treatment was considerably reduced. Cite this article: Bone Joint J 2018;100-B:527–34

Aims. Extendible endoprostheses have been available for more than 30 years and have become more sophisticated with time. The latest generation is ‘non-invasive’ and can be lengthened with an external magnetic force. Early results have shown a worryingly high rate of complications such as infection. This study investigates the incidence of complications and the need for further surgery in a cohort of patients with a non-invasive growing endoprosthesis. Patients and Methods. Between 2003 and June 2014, 50 children (51 prostheses) had a non-invasive growing prosthesis implanted for a primary bone sarcoma. The minimum follow-up was 24 months for those who survived. Their mean age was 10.4 years (6 to 14). The incidence of complications and further surgery was documented. Results. The mean follow-up was 64 months (20 to 145). The overall survivorship of the patients was 84% at three years and 70% at five years. Revision-free survival was 81.7% at three years and 61.6% at five years with competing risk analysis. Deep infection occurred in 19.6% of implants at a mean of 12.5 months (0 to 55). Other complications were a failure of the lengthening mechanism in five prostheses (9.8%) and breakage of the implant in two (3.9%). Overall, there were 53 additional operations (0 to 5 per patient). A total of seven patients (14%) underwent amputation, three for local recurrence and four for infection. Their mean limb length discrepancy was 4.3 mm (0 to 25) and mean Musculoskeletal Tumor Society Score functional score was 26.5 (18 to 30) at the final follow-up. Conclusions. When compared with previously published early results, this mid-term series has shown continued good functional outcomes and compensation for leg-length discrepancy. Infection is still the most common complication: post-operative wound healing problems, central line infection and proximal tibial location are the main risk factors. Cite this article: Bone Joint J 2016;98-B:1697–1703

Patients with transfemoral amputation (TFA) often experience problems related to the use of socket-suspended prostheses. The clinical development of osseointegrated percutaneous prostheses for patients with a TFA started in 1990, based on the long-term successful results of osseointegrated dental implants. Between1999 and 2007, 51 patients with 55 TFAs were consecutively enrolled in a prospective, single-centre non-randomised study and followed for two years. The indication for amputation was trauma in 33 patients (65%) and tumour in 12 (24%). A two-stage surgical procedure was used to introduce a percutaneous implant to which an external amputation prosthesis was attached. The assessment of outcome included the use of two self-report questionnaires, the Questionnaire for Persons with a Transfemoral Amputation (Q-TFA) and the Short-Form (SF)-36. The cumulative survival at two years’ follow-up was 92%. The Q-TFA showed improved prosthetic use, mobility, global situation and fewer problems (all p < 0.001). The physical function SF-36 scores were also improved (p < 0.001). Superficial infection was the most frequent complication, occurring 41 times in 28 patients (rate of infection 54.9%). Most were treated effectively with oral antibiotics. The implant was removed in four patients because of loosening (three aseptic, one infection). Osseointegrated percutaneous implants constitute a novel form of treatment for patients with TFA. The high cumulative survival rate at two years (92%) combined with enhanced prosthetic use and mobility, fewer problems and improved quality of life, supports the ‘revolutionary change’ that patients with TFA have reported following treatment with osseointegrated percutaneous prostheses. Cite this article: Bone Joint J 2014;96-B:106–13

We determined the short-term clinical outcome and migration within the bone of the humeral cementless component of the Instrumented Bone Preserving (IBP) total elbow replacement in a series of 16 patients. There were four men and 12 women with a mean age at operation of 63 years (40 to 81). Migration was calculated using radiostereometric analysis. There were no intra-operative complications and no revisions. At two-year follow-up, all patients showed a significant reduction in pain and functional improvement of the elbow (both p < 0.001). Although ten components (63%) showed movement or micromovement during the first six weeks, 14 (88%) were stable at one year post-operatively. Translation was primarily found in the proximal direction (median 0.3 mm (interquartile range (IQR) -0.09 to 0.8); the major rotational movement was an anterior tilt (median 0.7° (IQR 0.4° to 1.6°)). One malaligned component continued to migrate during the second year, and one component could not be followed beyond three months because migration had caused the markers to break off the prosthesis. This study shows promising early results for the cementless humeral component of the IBP total elbow replacement. All patients had a good clinical outcome, and most components stabilised within six months of the operation. . Cite this article: Bone Joint J 2014;96-B:229–36

Introduction. In rheumatoid patients the use of a long intramedullary stem in ipsilateral shoulder and elbow replacement carries the risk of humeral fracture of the small area of unviolated bone between the implants. Healing may be compromised. Because of this a short stemmed humeral head prosthesis was designed which rests on the bone surface after resection of the humeral head instead to be fixed in the shaft of the humerus. Since 1994 this prosthesis, specially designed for the rheumatoid patients has been in use in our clinic. The design rationale and the clinical results will be presented. Result. Since 1994 the short stemmed shoulder prosthesis has been inserted by the author in 54 shoulders. 8 Patients had osteoarthritis, 42 patients rheumatoid arthritis, 3 patients osteonecrosis and 1 patient a post-traumatic osteoarthritis. The average age was 65 years (range 32–83). In 19 shoulders a total shoulder arthroplasty was performed and the 36 shoulders a hemiarthroplasty. 32 Patients had a follow-up of more than 1 year and the average follow-up in this group is 2. 5 years (range 1-5. 5). All patients were scored clinically with the HSS score and the Constant score and radiographically before the operation, 1 year after the operation and after that at regular intervals. At follow-up pain decreased in all patients but more than 50% of the shoulders still had some mild or moderate pain during daily activities. Pre-operatively active forward flexion averaged 61°, external rotation 10° and abduction 50°. Postoperatively the active forward flexion increased to 75°, the external rotation to 19° and the abduction to 67°. The gain in ROM is similar to a group of patients operated in the same time period with another shoulder prosthesis. Discussion. The short stem shoulder prosthesis is a good alternative for a shoulder prosthesis with a long intra medullary stem. The clinical results with regards to pain reflief and gain in ROM are similar. The long term fixation of short sem humeral prosthesis remains good, without signs of radiolucency or migration. The advantage of a short stem prosthesis are:. easy technique to reconstruct the anatomical position of the humeral head. bone sparing. no stress shielding of the shaft. no surgical problems when a long stemmed elbow prosthesis is used. possibility for revision

Aims

The Exeter V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing implant fractures between the Exeter V40 series; 125 mm and conventional length stem systems.

Extensive and severe bone loss of the femur may be a result of a failed total hip arthroplasty (THA) or total knee arthroplasty (TKA) with multiple revision surgeries which may be caused by factors such as infection, periprosthetic fracture or osteolysis. The aim of this study was to assess outcomes of using the “Push-Through Total Femoral Prosthesis” (PTTF) for revision of a total hip replacement with extreme bone loss.

Fourteen patients who had extensive bone defects of the femur due to failed THR's and were treated with PTTF between 2012 and 2020 were included in this study. Primary functional outcomes were assessed using Harris Hip Score (HHS), Toronto Extremity Salvage Score (TESS) and Musculoskeletal Tumor Society (MSTS) scores. Range of motion, complications, and ambulatory status were also recorded to assess secondary outcomes.

Two of 14 patients underwent surgery with PTTF for both knee and hip arthroplasty revision. The mean time between index surgery and PTTF was 15 years (3 to 32 yrs.). Acetabular components were revised in six of 14 patients. After a mean follow-up of 5.9 years, hip dislocations occurred in 3 patients. All dislocated hips were in patients with retained non-constrained acetabular bearings. Patient satisfaction was high (MSTS: 67%, HHS: 61.2%, TESS 64.6%) despite a high re-operation rate and minor postoperative problems.

PTTF is a unique alternative that may be considered for a failed THA revision procedure in patients with an extreme femoral bone defect. Patients are able to ambulate pain free relatively well. Routine usage of constrained liners should be considered to avoid hip dislocation which was our main problem following the procedure.

Introduction. This study reports outcomes of 35 revisions of a recalled metal-on-metal (MOM) monoblock prosthesis performed by a single surgeon. Methods. We prospectively collected data on all patients who underwent revision of a recalled metal-on-metal monoblock prosthesis between 2010 and 2015. Average follow-up was 2.5 years post-revision and 6.9 years post-primary procedure. We evaluated the cohort for age, BMI, gender, existence of medical comorbidities, and post-op complications. We compared pre and post-revision cup abduction angles, anteversion angles, combined angles, cup sizes, and Harris Hip Scores. Cobalt and chromium levels were followed throughout the study period for each patient. Results. Thirty-one patients underwent 35 revisions surgeries for pain, high metal ions, infection, aseptic loosening, failure of ingrowth, leg length discrepancy and/or pseudotumor. Two of these revisions were subsequently re-revised – one for continued pain and one for failure involving multiple dislocations, breakage of screws, and acetabular fracture. The survival rate for our revisions to date is 94.3%. Female patients comprised a majority of revisions (54%) despite comprising a minority (28%) of primary hip replacements using the studied prosthesis. Revised patients were an average of 51.8 years of age with a BMI of 31.07. Demographics are included on Table 1. There were five post-operative complications, including 2 infections, 2 dislocations, and one DVT. Cups were revised from a mean abduction angle of 47.5° in primary hips to 42.3° in revisions. Cups were revised from a mean of 53.4 to 57.8. Cobalt and chromium levels were followed in all patients and showed significant decrease after revision (Graph 1). Cobalt levels decreased from an average of 33.7 to 13.1 ng/mL while Chromium levels decreased from an average of 12.4 to 9.2 ng/mL. Harris Hip Scores increased significantly after revision (45.8 to 72.1). Conclusion. This study presents 35 revisions of a recalled monoblock hip prosthesis performed by a single surgeon at our institution from 2010 to 2015. To our knowledge, this is the largest single-surgeon study reported in the literature. Acetabular cups were revised to a lower average abduction angle. Patients have had significant improvements in Harris Hip Scores and significant decreases in Cobalt and Chromium levels after revisions. Our revision survival rate to date is 94.3% at an average of 2.5 years (range 2 weeks – 4.3 years). To view tables/figures, please contact authors directly

Background. The use of reverse total shoulder arthroplasty considerably increased since first introduced by Paul Grammont in the late 1980s. Over the past few years, results from several mid- and long-term clinical studies have demonstrated good functional outcomes and pain relief. However, several complications, especially inferior glenoid notching, and high revision rates were reported in the literature. Improvements in prosthesis design should contribute to a lower complication rate and lesser amount of glenoid erosion. Few studies have reported the clinical outcome andcomplications of Anatomical Shoulder Inverse/ Reverse Prosthesis. This study documents 2- and 6-year clinical and radiological results following reversed shoulder arthroplasty using this novel prosthesis. Methods. We report the results for sixty-eight consecutive patients (seventy shoulders) with cuff tear arthropathy (CTA) treated with Anatomical Shoulder Inverse/Reverse Prosthesis between 2006 and 2008. Two groups were defined: (A) primary treatment and (B) revision. Clinical evaluation tools comprised Constant-Murley score (CS), range of motion, and a visual analog scale to assess pain. Radiographs (anteroposterior view in neutral position) were evaluated for notching and radiolucent lines. Any complications were recorded. Results. In total, 66 shoulders (94%) with a mean follow-up of 30.0 months were initially analysed. CS increased from preoperatively 20.2 to postoperatively 53.6 points. Inferior scapular notching was identified in 58% of patients, primarily grade 1 and 2 (low-graded). 16% of patients experienced a complication, including instability, infection or periprosthetic fracture. 58 patients (83%) were re-evaluated 69.0 months after implantation. CS decreased to 50.2 points (n.s.). 16 patients (23%) had postoperative complication at final follow-up. We observed progressive radiographic changes in 75% and an increased frequency of large notches (grade 3 and 4). No significant difference regarding clinical outcome was detected between group A and B after both 2 and 6 years. Conclusion. Total shoulder arthroplasty with the Anatomical Shoulder Inverse/Reverse Prosthesis is a reliable treatment option in patients with cuff tear arthropathy. Primary and revision arthropathies result in similar improvements in range of motion and pain. Constant-Murley score and radiographic changes deteriorated with time. Inferior scapular notching appeared rapidly after implantation. A change of prosthesis design and prosthetic overhang intraoperatively seems to be the most effective way to prevent scapular conflict. The complication rate in our series is equally to previously reported rates

Purpose of the study: Revision shoulder arthroplasty is generally considered to be a difficult procedure yielding modest improvement. Material and methods: We report a prospective study of 45 patients, aged 69.8 years (range 49–85 years). Thirty-two patients had a simple humeral prosthesis and thirteen a total prosthesis. A reversed prosthesis was used for all revisions. The reasons for the revisions were classified into five groups: failure of prosthesis implanted for fracture (36%), glenoid problems of a total shoulder arthroplasty (24%), prosthetic instability (18%), failure of a hemiarthroplasty implanted for rotator cuff tear (11%), failure of a hemiarhtroplasty implanted for post-traumatic osteoarthritis (11%). The revision consisted in replacement with a reversed prosthesis. Patients were assessed pre and postoperatively using the Constant score for the clinical assessment and plain x-rays for the radiological assessment. Results: Forty-one patients were reviewed at mean follow-up of 42.1 months (range 24–92). The four other patients died during the first two postoperative years. Subjectively, 73% of patients were satisfied. The Constant score improved from 187.7 to 55.6 on average. The best gain was obtained for the pain and daily activities scores. Discussion: Revision shoulder arthroplasty provides only moderate improvement. Neer called a limited goal surgery. Results published on revision shoulder arthroplasty using a non-constrained prosthesis show that the functional gain is moderate. Revisio with a reversed total prosthesis gives better results because of the lesser impact of the cuff deficiency. The rate of complications after revision is greater than with first intention implantations. Conclusion: Use of a reversed total shoulder prosthesis for revision shoulder arthroplasty provides encouraging results in terms of the mid-term functional outcome

Summary. Revision TKA using CCK prosthesis showed comparable outcome to PS prosthesis in clinical and radiological results. Introduction. In revision total knee arthroplasty (TKA), the goal should be to obtain good motion, function and most importantly stability. The stability depends on remaining soft tissue and implant design. The more the ligaments retain function, the less the implant constraint is needed to achieve stability. With increased constraint, the transfer of joint reaction forces to implant-bone interface may lead to mechanical loosening of the implant. Constrained condylar knee (CCK) prosthesis provides more constraint compared with posterior stabilized (PS) prosthesis. The purpose of this study was to compare the clinical, radiological outcome and survivorship of CCK and PS prosthesis in revision TKA. Materials and Methods. One hundred and twenty-one consecutive revision TKAs using CCK (79 knees) and PS (42 knees) were included. The mean follow-up period was 63.2 months for CCK and 64.8 months for PS. The mean age was 69.5 years and 70.6 years in CCK and PS, respectively. Range of motion (ROM), American Knee Society (AKS) score, Hospital for Special Surgery (HSS) score, complications and failure rate were assessed. Radiographic measurements included tibiofemoral angle and radiolucent lines. The Kaplan-Meier survivorship analysis was performed with an end point of re-revision surgery for any reason and compared between CCK and PS using the Log-rank test. Results. The mean range of motion improved from 97.5° to 115.9° in PS, from 89.5° to 110.1° in CCK. The mean Knee Society knee and functional scores improved from 47.6 and 36.4 to 89.7 and 66.1 with PS, from 53.5 and 41.7 to 79.2 and 66.8 with CCK. The mean Hospital for Special Surgery knee score also improved from 57 to 76.9 and 59.7 to 77.6, respectively. The complication rate was 7.5% (4 cases; 3 recurred infections, 1 instability) in PS and 10.3% (7 cases; 4 recurred infections, 1 periprosthetic fracture, 2 stem tip pains) in CCK. The Kaplan–Meier survivorship analysis revealed that ten year survival of the components was 85.4% for PS and 80.0% for CCK. In all aspects, there were no statistical difference (a p-value of more than 0.05) between PS and CCK. Conclusion. Revision TKA using CCK prosthesis showed comparable outcome to PS prosthesis in clinical and radiological results. CCK prosthesis is a reliable and successful option for prosthesis selection in revision TKA when PS prosthesis is not enough for management of instability

Aim. Shoulder prosthesis chronic infection is a rare but serious complication, likely to lead to re-interventions and poor functional outcome. Two-stage exchange surgery is considered the standard procedure by most authors. Our hypothesis was that one-stage revision procedure is a valid therapeutic option in the management of chronic infections of shoulder arthroplasty. Method. This was a mono-center retrospective cohort study. All patients who underwent, during the inclusion period, a one-stage revision procedure for a chronic infection of shoulder arthroplasty were included. All patients underwent clinical evaluation (Constant-Murray score), radiological examination (standard X-rays) and a blood test (Complete Blood Count and C-reactive protein), at a minimal one-year follow-up. Primary endpoint of this study was the infectious outcome and secondary endpoints were the functional and radiographic outcomes. Results. 16 shoulder prosthesis in 14 patients (5 females, 9 males) were included. Mean time between primary prosthesis implantation and exchange surgery was 40 months (1–145). Mean follow up was 30,5 months. The principal micro-organism involved was Propionibacterium acnes (9/16) and multiple organisms were found in 6 patients. In 14/16 (87,5%) shoulders, we found no sign of persistent infection at last follow-up. 2/16 (12,5%) shoulders were considered as still infected. On these 2 patients still infected, one refused further revision and the other was not in a good enough medical condition to undergo another procedure. 2 patients required an additional one-stage procedure for a new infection (new pathogen) after a period of two years, both free of infection at last follow-up. At last follow-up, mean Constant score was 54,8 (23–82). 7/14 (50%) patients were satisfied or very satisfied with the global fonctionnal result. Conclusions. One-stage revision procedure seems to be a valid therapeutic option in the management of infected shoulder prosthesis, as it allowed us to eradicate the infection in 87,5% patients in our serie, with a fair clinical result

Purpose. This study compares outcomes in patients with complete congenital fibula absence, associated with severe lower limb deformity, treated with an amputation protocol to those using an extension prosthesis. Method. 32 patients were identified. 9 patients (2M: 7F, median age at presentation of 22 yrs) utilized an extension prosthesis. 23 patients (16M: 7F, median age at presentation of 10 months) underwent 25 amputations during childhood: only two underwent tibial kyphus correction to facilitate prosthetic wear. Mobility was assessed using the SIGAM and K scores. Quality of life was assessed using the PedsQL inventory questionnaire; pain by a verbal severity score. Patients undergoing amputation were further subdivided by age, below and above 2 yrs at the time of surgery. Results. 19 Syme and one Boyd amputation in 19 patients were performed early (mean age 15 months). 4 Syme and one trans-tibial amputation in 4 patients took place in older children (mean age 6.6 years). K Scores were significantly higher (mean 4 versus 2) and pain scores lower in the amputation group allowing high impact activity compared to community ambulation with an extension prosthesis. The SIGAM and PedsQL scores were all better in the amputation group, but not significantly so. There was no significant difference in the scores based on the time of amputation. Conclusion. Complete fibula absence can present with significant lower limb deformity. Parental counselling regarding management is paramount in achieving the optimum functional outcome. Childhood amputation for severe limb length inequality and foot deformity in congenital fibula absence offers excellent short term functional outcome with prosthetic support. The tibial kyphus deformity does not need routine correction and facilitates prosthetic suspension. Accommodative extension prosthesis does offer reasonable long term function but outcome scores are lower

Summary Statement. The constraint behavior of total knee arthroplasty (TKA) prosthesis usually has to be physically tested. This study presents a computer simulation model using finite element analysis (FEA) and demonstrates its effectiveness in predicting the femorotibial constraint behavior of TKA implants. Introduction. TKA prostheses are semi-constrained artificial joints. A well-functioning TKA prosthesis should be designed with a good balance between stability and mobility, meaning the femorotibial constraint of the artificial joint cannot be excessive or too lax. To assess the constraint behavior of a TKA prosthesis, physical testing is usually required, and an industrial test standard has been developed for this purpose. Benefiting from technological advancement, computer simulation has become increasingly useful in many industries, including medical device research and development. FEA has been extensively used in stress analysis and structural evaluation of various orthopaedic implants. This study presented an FEA-based simulation to evaluate the femorotibial constraint behavior of TKA prosthesis, and demonstrated the effectiveness of the method by validating it through physical testing. Methods. A Cruciate Retaining (CR) TKA prosthesis design (Optetrak Logic CR, size 3, Exactech, FL, USA) was used in this study. The prosthesis system consists of a femoral component, a tibial insert, and a tibial baseplate. CAD models of the implants assembled at 0° of flexion were used for the simulation. Finite element models were generated using 10-node tetrahedral elements, with all materials considered linear elastic. Boundary conditions were set up according to the ASTM F1223 standard. The tibial baseplate was fixed distally. A constant compressive force (710 N) was applied on the femoral component. Nonlinear Surface-Surface-Contact was defined at the femorotibial articulating surfaces as well as between the tibial insert and tibial baseplate. A coefficient of friction of 0.2 determined from the physical test was input into the simulation. The femoral component was driven under a displacement-controlled scheme to slide along the anterior-posterior (AP) direction on the tibial insert. At each time step, constraint force occurring at the articulating surface was derived from the reaction force at the distal fixation of the tibial baseplate. The force-displacement curve was plotted by combining the results of all time steps to characterize the constraint behavior of the prosthesis. A nonlinear FEA solver (NX Nastran SOL601, Siemens, TX, USA) was used to solve the simulation. In addition, five samples of the prostheses were physically tested per ASTM F1223. Simulation results were compared to the physical testing. Results. The simulation successfully captured the movement of contact location and pressure along the movement of the femoral component. The force-displacement curve predicted by the simulation exhibited a very close hysteresis loop profile as the results of physical testing. Using the curve slope from 0 to 5 mm to characterise the constraint in the most relevant displacement range, the simulation predicted 45.7 N/mm anteriorly and 36.4 N/mm posteriorly, which are less than 10% different from the physical testing results (46.4 N/mm anteriorly and 39.6 N/mm posteriorly). Discussion/Conclusion. This study demonstrated that the simulation was able to closely predict the femorotibial constraint behavior of the TKA prosthesis under ASTM F1223 testing. The simulation results resembled the physical test results not only in the general profile of the curve but also in the magnitude of slope values. The increased difference at the far anterior region could be related to the fact that no material nonlinearity was considered in the current simulation, a factor that could be improved in future studies. A validated simulation method could be very useful in TKA prosthesis design. Since no physical prototypes are required, design evaluation and optimization can be achieved in a much easier and faster manner

Introduction. Ultra-high molecular weight polyethylene (UHMWPE) is the sole polymeric material currently used for weight- bearing surfaces in total joint replacement. However, the wear of UHMWPE in the human body after total joint replacement causes serious clinical and biomechanical reactions. Therefore, the wear phenomenon of UHMWPE is now recognized as one of the major factors restricting the longevity of artificial joints. In order to minimize the wear of UHMWPE and to improve the longevity of artificial joints, it is necessary to clarify the factors influencing the wear mechanism of UHMWPE. Materials and Methods. In a previous study (Cho et al., 2016), it was found that roundness (out-of-roundness) of the retrieved UHMWPE acetabular cup liner [Figure 1(a)] had a tendency to increase with increasing roundness of the retrieved metal femoral head [Figure 1(b)]. It appears that roundness of the femoral head contributes to increase of wear of the polyethylene liners. We focused on the roundness of femoral head as a factor influencing the wear of polyethylene liner in hip prosthesis. In this study, further roundness measurements for 5 retrieved metal femoral heads were performed by using a coordinate measuring machine. The elasto-plastic contact analyses between femoral head and polyethylene liner using the finite element method (FEM) were also performed in order to investigate the influence of femoral head roundness on the mechanical state and wear of polyethylene liner in hip prosthesis. Results. The range of roundness of the 5 retrieved metal femoral heads measured in this study was 14.50∼44.70 µm. Two examples of the results of FEM contact analyses are shown in Figure 2. Figure 2(a) is the results of the repeated contact analysis between femoral head and polyethylene liner under constant axial loading of 1000 N. Figure 2(b) is the results of the repeated contact analysis between femoral head and polyethylene liner under hip joint loading during normal gait. These figures show the distribution of the contact stress (von Mises equivalent stress) in the polyethylene liner. The graph in Figure 3 shows the changes in the maximum contact stress in the polyethylene liner with the flexion/extension angle of femoral head. Discussion and Conclusions. As the results of a series of the FEM contact analyses, it was found that repeated high contact stresses which exceed the yield stress of UHMWPE caused by roundness of the metal femoral head occurred in the polyethylene liner as shown in Figures 2 and 3. It was also found that the magnitude and amplitude of the repeated contact stresses had a tendency to increase with increasing roundness of the femoral head and axial loading applied to the femoral head. The results of this analytical study suggest that the roundness (out-of- roundness) of the femoral head is associated with accelerating and/or increasing wear of the UHMWPE acetabular cup liner in a hip prosthesis after total hip replacement. For any figures or tables, please contact authors directly

This paper describes a prosthesis for patients who have had a partial amputation of the hand, or who have congenital absence of all or part of the hand. The prosthesis incorporates a new concept whereby the grip is operated by flexion and extension of the wrist. A covering for the prosthesis has been developed using a silicone polymer which produces a lifelike flexible glove. Thirteen patients have so far been fitted with this type of prosthesis, which can give good function and cosmesis

In older patients (>75 years of age), with an intact rotator cuff, requiring a total shoulder replacement (TSR) there is, at present, uncertainty whether an anatomic TSR (aTSR) or a reverse TSR (rTSR) is best for the patient. This comparison study of same age patients aims to assess clinical and radiological outcomes of older patients (≥75 years) who received either an aTSR or a rTSA.

Consecutive patients with a minimum age of 75 years who received an aTSR (n=44) or rTSR (n=51) were prospectively studied. Pre- and postoperative clinical evaluations included the ASES score, Constant score, SPADI score, DASH score, range of motion (ROM) and pain and patient satisfaction for a follow-up of 2 years. Radiological assessment identified glenoid and humeral component osteolysis, including notching with a rTSR.

Postoperative improvement for ROM and all clinical assessment scores for both groups was found. There were significantly better patient reported outcome scores (PROMs) in the aTSR group compared with the rTSR patients (p<0.001). Both groups had only minor osteolysis on radiographs. No revisions were required in either group. The main complications were scapular stress fractures for the rTSR patients and acromioclavicular joint pain for both groups.

This study of older patients (>75 years) demonstrated that an aTSR for a judiciously selected patient with good rotator cuff muscles can lead to a better clinical outcome and less early complications than a rTSR.

Commonly used alterations of prosthetic surfaces include grit-blasting (GB), plasma-sprayed titanium (Ti) or hydroxyapatite (HA) coating. Systemic concentrations of cobalt (Co) and chromium (Cr) are elevated in patients with metal-on-metal hip replacement, but can occur for all modular hip replacements. Here, we use whole genome microarrays to assess differential gene expression in primary human osteoblasts grown in vitro and on these prosthesis surfaces following exposure to clinically relevant concentrations of Co and Cr. Mesenchymal cells obtained from bone-fragments of 3 patients undergoing joint replacement surgery were differentiated into osteoblasts. Subsequently, cells were cultured in vitro on tissue-culture plates (TCP), or on GB, Ti and HA surfaces (JRI Orthopaedics Ltd, Sheffield, UK). Following 24hr exposure to a combination of clinically equivalent concentrations of Co2+:Cr3+, RNA was extracted and hybridized to SurePrint-G3 Gene Expression Microarray. Probe signals were normalised using ‘Limma’ package on R-Bioconductor and differential gene expression assessed with empirical Bayes approach (Log2FC>1.00, P<0.001 for differentially expressed genes). For cells grown on TCP, 11 genes were upregulated with 500μg/L Co2+:Cr3+. Of these, 4 were associated to HIF-1 signalling based on KEGG pathway analysis (P=5.4e-5). Exposure to 1000μg/L Co2+:Cr3+ altered expression at 164 loci for HA surfaces, and a separate 50 loci for Ti surfaces compared to GB surfaces. Genes for osteoblast differentiation (BMP2 and RGS2) were downregulated on HA surfaces compared to GB, whilst genes for cell-adhesion (ESAM), vesicular trafficking (RAB37) and protection against oxidative damage (NRF2) were upregulated. Ti surfaces caused an upregulation in ERBB3 and CNTF, which are associated with inhibition of osteoblast differentiation and mineralisation, when compared to GB surfaces. This study confirms the role of HIF-1 signalling in response to prosthesis generated metal ions, and is the first to provide a comprehensive genome-wide insight into transcriptional response of osteoblasts at prosthesis surface to clinically equivalent metal exposure

Intraosseous Transcutaneous Amputation Prosthesis (ITAP) is a new generation of limb replacements that can provide to amputees, an alternative solution to the main problems caused by the most common used external prosthesis such as pressure sores, infections and unnatural gait. ITAP is designed as one pylon osteointegrated into the bone and protruding through the skin, allowing both the mechanical forces to be directly transferred to the skeleton and the external skin being free from frictions and infections. The skin attachment to the implant is fundamental for the success of the ITAP, as it prevents the implant to move and consequently fail. In this study we wanted to test if cell viability and attachment was improved using TiO2 nanotubes. Human keratinocytes and human dermal fibroblasts were seeded for three days on TiO2 nanotubes with different sizes (18–30nm, 40–60nm and 60–110nm), compared with controls (smooth titanium) and tested for viability and attachment. A Mann-Whitney U test was used to compare groups where p values < 0.05 were considered significant. The results showed that the viability and cell attachment for keratinocytes were significantly higher after three days on controls comparing with all nanotubes (p=0.02), while attachment was higher on bigger nanotubes and controls. Cell viability for fibroblasts was significantly higher on nanotubes between 40 and 110nm comparing with smaller size and controls (p=0.03), while investigation of cell attachment is ongoing. From these early results, we can say that TiO2 nanotubes can improve the soft tissue attachment on ITAP. Further in-vitro and ex-vivo experiments on cell attachment will be carried out

1. Forty-five arthroplasties of the knee with the Walldius prosthesis are reported in forty-two patients, thirty-seven with rheumatoid arthritis and five with osteoarthritis. 2. There has been no structural failure of the prosthesis. 3. Sepsis required removal of the prosthesis in three cases, but arthrodesis was obtained in two of the three. 4. Serious loosening of the prosthesis occurred in one case only. Varus deformity occurred in one patient. 5. Radiological evidence of some movement of the prosthesis was present in six other cases but this did not seem to affect function. 6. It is concluded that this operation has a place in the treatment of the more seriously disabled patient, but should not be used when heavy demands are likely to be made on the joint

Introduction. Total knee arthroplasty (TKA) prostheses are semi-constrained artificial joints. A well-functioning TKA prosthesis should be designed with a good balance between stability and mobility, meaning the femorotibial constraint of the artificial joint should be appropriate for the device's function. To assess the constraint behavior of a TKA prosthesis, physical testing is typically required, and an industrial testing standard has been developed for this purpose [1]. Computer simulation has become increasingly useful in many industries, including medical device research and development where finite element analysis (FEA) has been extensively used in stress analysis and structural evaluation. This study presents an FEA-based simulation to evaluate the femorotibial constraint behavior of TKA prosthesis, and demonstrated the effectiveness of the method by validating through physical testing. Methods. A Cruciate Retaining (CR) TKA prosthesis design (Optetrak Logic CR, Exactech, USA) was used in this study. CAD models of the implants assembled at 0° of flexion were used for the simulation. Finite element models were generated using with all materials assumed linear elastic. Boundary conditions were set up according to the ASTM F1223 standard (Figure 1). The tibial baseplate was fixed distally. A constant compressive force (710 N) was applied on the femoral component. Nonlinear Surface-Surface-Contact was defined at the femorotibial articulating surfaces. Coefficient of friction was determined from physical test. The femoral component was driven under a displacement-controlled scheme to slide along the anterior-posterior (AP) direction on the tibial insert. At each time step, constraint force occurring at the articulating surface was derived from the reaction force at the distal fixation of the tibial baseplate. A nonlinear FEA solver (NX Nastran SOL601, Siemens, USA) was used to solve the simulation. In addition, five samples of the prostheses were physically tested, and the results were compared with the simulation. Results. The simulation successfully captured the movement of contact location and pressure along the movement of the femoral component (Figure 2). The force-displacement curve predicted by the simulation exhibited a very close hysteresis loop profile as the results of physical testing (Figure 3). Using the curve slope from 0 to 5 mm to characterize the linear constraint, the simulation predicted 45.7 N/mm anteriorly and 36.4 N/mm posteriorly, which are less than 10% different from the physical testing results (46.4 N/mm anteriorly and 39.6 N/mm posteriorly). Discussion/Conclusion. This study demonstrated that the simulation was able to closely predict the femorotibial constraint behavior of the TKA prosthesis under ASTM F1223 testing. The simulation results resembled the physical testing results not only in the general curve profile but also in the magnitude of slope values. The increased difference at the far anterior region could be related to the fact that no material nonlinearity was currently considered, which could be improved in future studies. A validated simulation method could be very useful in TKA prosthesis design. Since no physical prototypes are required, design evaluation and optimization can be achieved in a much easier and faster manner

Background. Scapular notching is a complication after reverse shoulder arthroplasty with a high incidence up to 100%. Its clinical relevance remains uncertain; however, some studies have reported that scapular notching is associated with an inferior clinical outcome. There have been no published articles that studied positional relationship between the scapular neck and polyethylene insert in vivo. The purpose of this study was to measure the distance between the scapular neck and polyethylene insert in shoulders with Grammont type reverse shoulder arthroplasty during active external rotation at the side. Methods. Eighteen shoulders with Grammont type prosthesis (Aequalis Reverse, Tornier) were enrolled in this study. There were 13 males and 5 female, and the mean age at surgery was 74 years (range, 63–91). All shoulders used a glenosphere with 36mm diameter, and retroversion of the humeral implant was 10°in 4 shoulders, 15°in 3 shoulders, and 20°in 11 shoulders. Fluoroscopic images were recorded during active external rotation at the side from maximum internal to external rotation at the mean of 14 months (range, 7–24) after surgery. The patients also underwent CT scans, and three-dimensional glenosphere models with screws and scapula neck models were created from CT images. CT-derived models of the glenosphere and computer-aided design humeral implant models were matched with the silhouette of the implants in the fluoroscopic images using model-image registration techniques (Figure 1). Based on the calculated kinematics of the implants, the closest distance between the scapular neck and polyethylene insert was computed using the scapular model and computer-aided design insert models (Figure 2). The distance was computed at each 5° increment of glenohumeral internal/external rotation, and the data from 20°internal rotation to 40°external rotation were used for analyses. One-way repeated-measures analysis of variance was used to examine the change of the distance during the activity, and the level of significance was set at P < 0.05. Results. The mean glenohumeral abduction during the activity was 17°-22°. The mean distance between the neck and insert was approximately 1mm throughout the activity (Figure 3). The distance tended to become smaller with the arm externally rotated, but the change was not significant. Discussion. The reported incidence of scapular notching after Grammont type reverse shoulder arthroplasty is generally higher than the newer design prosthesis with the lateralized center of rotation. This may be associated with the design of the prosthesis, and the results of this study that the distance between the neck and insert was approximately 1mm throughout active external rotation at the side will support the high incidence of notching. We may need to analyze the distance with the newer design reverse shoulder prosthesis to prove the architectural advantage of the newer systems. Conclusion. The distance between the scapular neck and polyethylene insert was approximately 1mm throughout active external rotation activity in shoulders with Grammont type prosthesis

Introduction. Ultra-high molecular weight polyethylene (UHMWPE) is the sole polymeric material currently used for weight- bearing surfaces in total joint replacement. However, the wear of UHMWPE and the polyethylene wear debris generated in the human body after total joint replacement cause serious clinical and biomechanical reactions. Therefore, the wear phenomenon of UHMWPE in total joint replacement is now recognized as one of the major factors restricting the longevity of these implants. In order to minimize the wear of UHMWPE and to improve the longevity of artificial joints, it is necessary to clarify the factors influencing the wear mechanism of UHMWPE. Materials and Methods. The wear and/or failure characteristics of 33 retrieved UHMWPE acetabular cup liners of hip prostheses were examined in this study. The retrieved liners had an average in vivo duration of 193.8 months (75 to 290 months). Several examples of the retrieved liners are shown in Figure 1. The elasto-plastic contact analyses between metal femoral neck and polyethylene liner and between metal femoral head and polyethylene liner using the finite element method (FEM) were also performed in order to investigate the factors influencing the wear and/or failure mechanism of the polyethylene liner in hip prosthesis. Results. In the examination of the retrieved polyethylene liners, the generation of component impingement was observed in 24 cases of the 33 retrieved liners (72.7%) as shown in Figures 1(a) and (b). In addition, the generation of cold flow into the screw holes in the metal acetabular cup was observed in 27 cases of the 33 retrieved liners (81.8%) as shown in Figures 1(c) and (d). Several examples of the results of the FEM contact analyses are shown in Figure 2. In the simulation of the component impingement, it was found that high contact stresses which exceed the yield stress of UHMWPE and considerable plastic strains occurred in the rim of the polyethylene liner as shown in Figures 2(a) and (b). In the simulation of the cold flow, it was found that the stress concentration near the edge of screw hole has significant influence on the states of contact stresses and plastic strains in the surface and undersurface (backside) of the polyethylene liner as shown in Figures 2(c) and (d). Discussion and Conclusions. In this study, we focused on the impingement between the metal femoral neck and the polyethylene liner and the cold flow into the screw holes on the backside of the polyethylene liner as the factors influencing the wear and/or failure of the UHMWPE acetabular cup liner in hip prosthesis. The results of these retrieval and analytical studies confirmed that the component impingement and the cold flow into the screw holes contribute to increase of wear and/or failure of the polyethylene liner. Therefore, it is necessary to improve resistance to the component impingement and the cold flow in order to decrease the wear and/or failure of the UHMWPE acetabular cup liner and to increase the longevity of hip prosthesis. For any figures or tables, please contact authors directly

Introduction. Advantages of ceramic materials for hip joint prosthesis are recognized to be high hardness, scratch resistance, improved wettability, lower friction and lower wear than CoCr surfaces. Recent studies suggest the use of ceramic femoral head reduce fretting corrosion at stem taper junction compared to metal-on-metal taper junction[1]. Continuous improvement of ceramic materials for orthopedic lead to the development of a resurfacing ceramic-on-ceramic hip joint prosthesis. The main differences of resurfacing heads respect to standard heads are their anatomical dimension and the empty shape suitable to cover the femoral bone and to connect with the resurfacing stem. Ceramic is essentially a brittle material and its strength is influenced by the minimum thickness in the stressed area. Ceramic resurfacing head minimum thickness is comparable with ceramic revision head already on the market. The aim of this study is to develop a mechanical pre-clinical analysis verification process for the newly developed system. Materials and methods. The empty shape of the ceramic resurfacing head may influence its strength in a crush loading scenario. Although this is not a physiological condition this test represents the most severe loading for a resurfacing head. Also comparative analysis can be done considering the yield point of conventional metal resurfacing heads reported by the FDA Center for Devices and Radiological Health. For this reason a static unsupported head strength test is performed by applying a compressive load perpendicular to the head axis along the equatorial plane[2](Fig.1). Resurfacing ceramic head made in ZTA is suitable both for a resurfacing stem and an adaptor to be coupled with a standard stem. Mechanical test was performed on worst case resurfacing head size both with resurfacing stem and standard stem based and on FE non linear analysis performed in ANSYS 17.2 according the following material properties: ZTA ceramic (modulus of elasticity E, Poisson ratio ν and density ρ of 348GPa, 0.23 and 4.25g/cm. 3. respectively), and Ti6Al4V (E=114GPa, ν=0.33 and ρ=4.43g/cm. 3. ). For comparison purposes unsupported test was performed on standard head Ø28#S both in Biolox®Delta and Biolox®Forte ceramic. At least three components were used for each test and the average values was compared with predicates[2]. Static compressive load was applied with MTS hydraulic actuators with load cell of 100kN. Results. FE analysis indicated the larger resurfacing head as the worst case size in the size range(Fig.2). Static unsupported head strength test was performed on resurfacing ceramic head Ø57 coupled both with resurfacing stem and standard stem, Biolox®Delta head Ø28#S, Biolox®Forte head Ø28#S and respectively reached a strength value of 53±7kN, 90±3kN, 78±27kN, 49±1kN. Equivalent test were reported in literature for DeltaSurf® Ø58 and BHR. TM. , and respectively reached a strength of 26kN and 5.6kN. Discussion and Conclusion. LIMA ceramic resurfacing head and Biolox Forte Ø28#S showed equivalent unsupported head burst strength. LIMA ceramic resurfacing head showed higher unsupported head burst strength respect to DeltaSurf® and BHR. TM. highlighting its potential in clinical use. For any figures or tables, please contact the authors directly

Mechanical loosening which begins with early-onset migration of the prosthesis is the major reason for failure of the Souter-Strathclyde elbow replacement. In a prospective study of 18 Souter-Strathclyde replacements we evaluated the patterns of migration using roentgen stereophotogrammetric analysis. We had previously reported the short-term results after a follow-up of two years which we have now extended to a mean follow-up of 8.2 years (1 to 11.3). Migration was assessed along the co-ordinal axes and overall micromovement was expressed as the maximum total point movement. The alignment of the prosthesis and the presence of radiolucent lines were examined on conventional standardised radiographs. All the humeral components showed increased and variable patterns of migration at the extended follow-up and four humeral components were revised. The maximum total point movement at two years in the revised prostheses was 1.8 mm (. sd. 1.0) and in the non-revised 0.7 mm (. sd. 0.5, p = 0.01). Most humeral components migrated into external rotation resulting in an anterior and varus tilt. The ulnar components remained stable

Introduction. Modern prostheses of the 3rd and 4th generation facilitate a precise adjustment to various humeral anatomies. This provides major advantages regarding soft tissue balancing and the reconstruction of the rotational center. Thus, high expectations are linked to the use of modern shoulder prostheses compared to conventional designs. Methods. Out of a prospective multicenter study, 108 cases (72 females, 36 males) were reviewed. All patients were treated with the same type of double eccentric shoulder prosthesis. The mean age at surgery was 71.5 years (range, 44.6 to 97.3). The Constant Score (CS), ASES Score, X-rays and complications were evaluated at 3, 6, 12 and 24 months as well as 4, 7 and 10 years follow-up. Results. At a mean follow-up time of 93.3 months, the mean CS improved from preoperative 25.6 (±8.8) to 63.8 (±19.1) points at 7 years. In the same period, the mean ASES Score improved from 24.5 (±12.5) to 79.6 (±19.1). Pain according to the CS was rated preoperatively as high (mean 1.8 points). After 7 years patients suffered from mild to no pain (mean 12.0 points). A total of 7 prostheses were revised, leading to an overall survival rate of 91.5% at 10 years. In 4 cases secondary glenoid erosion was the reason for revision. Conclusion. The clinical results of the investigated prosthesis system are convincing and comparable to other modern shaft prostheses. To achieve an anatomical reconstruction of the rotational center of the humeral head, the use of a double eccentric shoulder prosthesis is recommended

Purpose. This study compares outcomes in patients with complete congenital fibula absence treated with an amputation protocol to those using an extension prosthesis. Introduction. Complete fibula absence presents with significant lower limb deformity. Parental counselling regarding management is paramount in achieving the optimum functional outcome. Amputation offers a single surgical event with minimal complications and potential excellent functional outcome. Method. 32 patients were identified. 9 patients (2M: 7F, median age at presentation of 22yrs) utilized an extension prosthesis. 23 patients (16M: 7F, median age at presentation of 10 months) underwent 25 amputations during childhood: only two underwent tibial kyphus correction. Mobility was assessed using SIGAM and K scores. Quality of life was assessed using the PedsQL inventory questionnaire; pain by a verbal severity score. Results. 19 Syme and one Boyd amputation in 19 patients were performed early (mean age 15 months). 4 Syme and one trans-tibial amputation in 4 patients took place in older children (mean age 6.6 years). K Scores were significantly higher (mean 4 versus 2) and pain scores lower in the amputation group allowing high impact activity compared to community ambulation with an extension prosthesis. The SIGAM and PedsQL scores were all better in the amputation group, but not significantly so. Conclusion. Childhood amputation for severe limb length inequality and foot deformity in congenital fibula absence offers excellent short term functional outcome with prosthetic support. The tibial kyphus does not need routine correction and facilitates prosthetic suspension. Accommodative extension prostheses offer reasonable long term function but outcome scores are lower

Introduction. Ultra-high molecular weight polyethylene (UHMWPE) is the sole polymeric material currently used for weight- bearing surfaces in total joint replacement. However, the wear of UHMWPE in knee and hip prostheses after total joint replacement is one of the major restriction factors on the longevity of these implants. In order to minimize the wear of UHMWPE and to improve the longevity of artificial joints, it is necessary to clarify the factors influencing the wear of UHMWPE. A number of studies have investigated the factors influencing the wear of UHMWPE acetabular cup liner in hip prosthesis. Most of these studies, however, have focused on the main articulating surfaces between the femoral head and the polyethylene liner. Materials and Methods. In a previous study (Cho et al., 2016), the generations of cold flow into the screw holes in the metal acetabular cup were observed on the backside of the retrieved UHMWPE acetabular cup liners as shown in Figure 1. We focused on the screw holes in the metal acetabular cup (Figure 2) as a factor influencing the wear behavior of polyethylene liner in hip prosthesis. In this study, computer simulations of the generation of cold flow into the screw holes were performed using the finite element method (FEM) in order to investigate the influence of the screw holes in the metal acetabular cup on the mechanical state and wear behavior of polyethylene liner in hip prosthesis. Results. An example of the results of the FEM simulations performed in this study is shown in Figure 3. In the region which the cold flow into the screw holes occurred, it was found that locally high contact stresses which exceed the yield stress of UHMWPE and considerable plastic strains were generated throughout the overall thickness between the backside and top surface of the polyethylene liners. On the contrary, in the case of the polyethylene liner combined with the metal acetabular cup without screw hole, although the regions of high contact stress and high plastic strain had a tendency to be limited around contact surface compared with those of the combination with screw holes, the values of contact stress and plastic strain were lower than the combination with screw holes. Discussion and Conclusions. The results of this study suggest that the cold flow generated by the existence of the screw holes in the metal acetabular cup of hip prosthesis reduces the wear resistance of the UHMWPE acetabular cup liner. It would appear that the cold flow into the screw holes contributes to structural weakening of the UHMWPE and reduction of the polyethylene thickness, thus increase of internal stresses and plastic strains in and around the regions of cold flow. Therefore, it is required that improvement of the screw holes in the metal acetabular cup and/or improvement of fixation method of the metal acetabular cup to a pelvis in order to enhance the wear resistance of the polyethylene liner. For any figures or tables, please contact authors directly

Implant-related infection is one of the leading reasons for failure in orthopaedics and trauma, and results in high social and economic costs. Various antibacterial coating technologies have proven to be safe and effective both in preclinical and clinical studies, with post-surgical implant-related infections reduced by 90% in some cases, depending on the type of coating and experimental setup used. Economic assessment may enable the cost-to-benefit profile of any given antibacterial coating to be defined, based on the expected infection rate with and without the coating, the cost of the infection management, and the cost of the coating. After reviewing the latest evidence on the available antibacterial coatings, we quantified the impact caused by delaying their large-scale application. Considering only joint arthroplasties, our calculations indicated that for an antibacterial coating, with a final user’s cost price of €600 and able to reduce post-surgical infection by 80%, each year of delay to its large-scale application would cause an estimated 35 200 new cases of post-surgical infection in Europe, equating to additional hospital costs of approximately €440 million per year. An adequate reimbursement policy for antibacterial coatings may benefit patients, healthcare systems, and related research, as could faster and more affordable regulatory pathways for the technologies still in the pipeline. This could significantly reduce the social and economic burden of implant-related infections in orthopaedics and trauma.

Cite this article: C. L. Romanò, H. Tsuchiya, I. Morelli, A. G. Battaglia, L. Drago. Antibacterial coating of implants: are we missing something? Bone Joint Res 2019;8:199–206. DOI: 10.1302/2046-3758.85.BJR-2018-0316.

Introduction. The low-contact stress (LCS) knee prosthesis is a mobile-bearing design with modifications to the tibial component that allow for meniscal-bearing (MB) or rotating-platform (RP). The MB design had nonconstrained anteroposterior and rotational movement, and the RP design has only nonconstrained rotational movement. The anterior soft tissues, including patellar tendon (PT), prevent anterior dislocation of the MB. The PT may consistently be exposed to overstressing. Therefore, we hypothesized that the PT thickness and width in MB prosthesis revealed more morphological changes than those of RP prosthesis due to degeneration of the PT induced by much mechanical stress of the MB movement. To confirm this hypothesis, we analyze the PT thickness and width induced by mobile-bearing inserts. Objectives. Sixty LCS prostheses in 30 patients were analyzed. The average follow-up time was 61 months. MB prosthesis was used on one side of the knee and RP prosthesis was used on the contralateral side of the knee. All patients were chosen from group with no clinical complication, and all had achieved passive full extension and at least 90°of flexion. The average Hospital for Special Surgery Score was 94.6 ± 2.7. Methods. We measured the thickness and width of PT at joint line level, which were confirmed by sagittal section using ultrasound in knee extension between MB and RP design prosthesis. Results. The mean thickness of PT was 4.7 mm (1.2) with MB and 4.7 mm (1.0) with RP design prosthesis. The mean width of PT was 30.6 mm (3.2) with MB and 31.3 mm (3.5) with RP design prosthesis. No significant differences were found between both groups. Conclusion. The current results showed that the PT thickness and width in MB prosthesis did not reveal more morphological changes than those of RP prosthesis due to degeneration of the PT induced by much mechanical stress of the MB movement. The possible reasons are the following: (1) We did not remove infra-patellar fat pad, which might play shock absorber of mechanical stress from MB, and prevent from significant degeneration of PT, (2) MB inserts did not stimulate the middle of the PT directly, unlike LCS A/P-Glide inserts, and might come into contact with the both ends of the PT and (3) MB inserts did not move so as to cause degeneration in the PT

Culture negative prosthetic joint infections (PJI) still remain an issue even the advantages in PJI diagnosis. This is the reason why some orthopedic surgeons fear to use preoperative antibiotic prophylaxis when a PJI is suspected. The purpose of the present study was to evaluate the influence of preoperative antibiotic prophylaxis in intraoperative cultures. An enhanced diagnostic protocol for PJI (Zimmerli criteria) was used for the inclusion criteria in order to collect all PJI accounted in a University Hospital. Patients were prospectively randomized in two groups. The control group received the classical preoperative antibiotic prophylaxis. The study group did not receive prophylaxis prior to surgery. There were 14 patients in each group. They correspond to 13 infections of total hip arthroplasty (THA), 12 infections of total knee arthroplasty (TKA) and 3 reverse shoulder prosthesis (RSA) infections. There were 10 patients in the study group and 10 patients in the control group with at least one positive microbiological criterion. There were 8 patients in each group with culture negative PJI (p>0.05). Preoperative antibiotic prophylaxis does not affect intraoperative cultures in suspected or confirmed PJI. Therefore it is essential to deliver antibiotic prophylaxis in any patient in which prosthesis is to be implanted in order to protect the prosthesis from infection

INTRODUCTION:. The 3D shape of the normal proximal femur is poorly described in current designs of proximal femur prosthesis. Research has shown that in current implant designs with small diameter femoral heads the moment arm of the ilio-psoas tendon is reduced causing weakness in full extension, while large femoral heads cause psoas tendon impingement on the femoral head neck junction [1]. The femoral head-neck junction thus directly influences the hip flexor muscles' moment arm. Mathematical modeling of proximal femoral geometry allowed a novel proximal femur prosthesis to be developed that takes into account native anatomical parameters. We hypothesized that it is possible to fit a quadratic surface (e.g. sphere, cylinder…) or combinations of them on different bone surfaces with a relatively good fit. METHODS:. Forty six ‘normal’ hips with no known hip pathology were segmented from CT data. Previous research has shown the femoral head to have a spherical shape [2], the focus here was therefore mainly on the neck. The custom-written minimization algorithm, using least squares approximation methods, was used to optimize the position and characteristics of the quadratic surface so that the sum of distances between a set of points on the femoral neck and the quadratic surface was minimized. Furthermore, to improve upon current design regarding the transition between head and the neck, we recorded the position of the head neck articular margin in addition the slope of the transition from head to neck in the above 46 hips. RESULTS:. The femoral neck was found to be represented with a good fit as a quadratic surface (hyperboloid) with an average root mean square error of 1.0 ± 0.13 among 46 hips. The femoral head was spherical with a mean ratio of 22.6 ± 1.75 mm. The shape of the femoral articular margin is a reproducible sinusoidal wave form, which appears to have two facets, one anterior and the other posterior. A sigmoid curve, provided by the Logistic Function was used to switch smoothly from the spherical head function to the hyperboloid neck function (Fig. 1). This curve provides a continuous mathematical function to describe the head/neck geometry. DISCUSSION:. Traditional designs that liken the femoral head to a sphere are an oversimplification of normal hip morphology. The precise shape of the neck and the relationship of the neck to the head are the basis of this invention. The prosthesis is designed to avoid soft tissue impingement and can be optimised in shape and size to match the patient's native morphology. Neck diameter and length can be designed to achieve the optimum head-neck ratio to further improve the range of motion produced. With the current design the pain observed due to ilio-psoas impingement to implant will be reduced. Furthermore as the implant is anatomical the function of muscles and their moment arm will be unaffected

Purpose: Consolidation of the tuberosity is the key to success of shoulder arthroplasty for fracture. The purpose of this study was to assess the number and causes of tuberosity complications in order to find solutions for this problem. Material and methods: This retrospective multicentric study included 334 shoulder prostheses implanted for fracture between 1991 and 2000. Two different prostheses were used: 300 standard Aequalis prostheses implanted between 1991 and 1997 (mean follow-up four years) and 31 Aequalis Fracture prosthesis between 1999 and 2000 (mean follow-up nine months). Radiological results were assessed on the postoperative and last follow-up x-rays. The Constant score was used for clinical assessment. Results: For the 300 standard prostheses, the Constant score was 54 points with active anterior elevation = 104°. For the 31 fracture prostheses, the Constant score was 58 points with active anterior elevation = 114°. According to the operator’s assessment, 49% of the postoperative radiological results were fair or poor and objectively 35% of the tuberosities were poorly positioned with the standard prosthesis and 22% with the fracture prosthesis. Twenty-six percent of the good or poorly positioned tuberosities migrated secondarily with the standard prosthesis and 10% with the fracture prosthesis. Statistically significant prognostic factors limiting tuberosity complications were: satisfactory initial osteosynthesis with correct prosthesis height and retroversion facilitated by use of the fracture system, rehabilitation in a specialised centre, relative immobilisation during the first postoperative month limiting exercises to balancing movements which divided the number of secondary migrations by two compared with immediate moblisation (14% versus 27%). Discussion: A precise analysis of the radiograms revealed a very high rate of tuberosity complications (50%). There has been little study of these complications which are underestimated in the literature. The Aequalis fracture prosthesis can reduce these tuberosity complications two-fold. Postoperative immobilisation also reduces two-fold tuberosity migrations. These observations are against the early passive motion advocated by Neer. Finally, the quality of tuberosity fixation is crucial for success. The surgeon must concentrate on this element, searching to achieve a perfectly positioned prosthesis on the peroperative x-ray

In 2006 the standard prosthesis for hip hemiarthroplasty in our unit was changed from the traditional Thompson prosthesis used for over 20 years to the monobloc Exeter Trauma Stem (ETS). The principle anticipated advantages were ease of stem implantation, improvement of orientation positioning and a consistency with modern proven femoral THR stem design. All patients selected for hemiarthroplasty replacement for a displaced subcapital fracture of the hip were eligible for inclusion. Failed previous surgical cases were excluded. The last 100 Thompson’s prostheses used before and the first 100 Exeter Trauma Stems undertaken after the changeover date were studied. Outcomes measured included surgical complications including infection, dislocation, fracture, necessity to ream etc. and technical adequacy of implant positioning based upon post-operative radiographs. Surgeon grade was recorded. There were no changes in surgical personnel. 206 consecutive patients were included in the study (age range 76–96); 67 men and 139 women. Data were collected prospectively as part of a comprehensive hip fracture audit. Initial results show that the rate of surgical complications is similar in both prosthesis groups. Radiographs demonstrate the presence of a learning curve in the use of the new prosthesis. On six occasions after December 2006 the Thompson prosthesis was used – this was due to unavailability of ETS prosthesis or where a very large femoral head (56mm) was required. The introduction of the ETS for hip hemiarthroplasty was successful. Initial conversion problems involved maintaining sufficient stock of the most commonly used size of prosthesis. Advantages were a low dislocation rate despite the greater potential for erroneous implant version and a reduction in the amount of femoral preparation required including reaming. Limitations of this study are the lack functional outcome and long term survivorship analysis

Objective. The purpose of the present study was to compare the clinical and radiographic results after TKA using a patellofemoral design modified prosthesis and its predecessor. The other purpose was to investigate whether the use of the recent prosthesis increase the risk of posterior tibial cortex injury or patellar fracture. Materials and Methods. The clinical and radiographic results of 300 knees which underwent TKA using the Attune®prosthesis (group A) were compared with those in a paired match-control group who underwent TKA using the P.F.C. Sigma® prosthesis (group B). The preoperative demographic data between the 2 groups did not differ significantly. The WOMAC, Feller and Kujala scores, and range of motion (ROM) were compared. The minimal distance between the tibial component stem to posterior tibial cortex, and the remnant patella thickness were compared. Results. The postoperative WOMAC score was better in the group A than in the group B (17.7 vs. 18.8, p=0.004). The postoperative ROM was greater in the group A than in the group B (131.4° vs. 129.0°, p=0.008). The postoperative Feller score was not different, but postoperative Kujala score was better in the group A. The minimal distance between the tibial component stem and posterior tibial cortex was significantly shorter in group A than in the group B (6.3mm vs 7.0mm, p<0.001). The proportion of high risk group for posterior tibial cortical injury, which had the minimal distance less than 4mm, was higher in the group A (20.0% vs 10.7%, p=0.002). The remnant patella was thinner in the group A than in the group B (14.8mm vs 15.7mm, p<0.001). The proportion of high risk group for patella fracture with remnant thickness of <12mm was higher in the group A (7.5% vs 2.1%, p=0.003). Conclusion. When comparing the clinical and radiographic results after TKA using the two prostheses of a design modified prosthesis and its predecessor, TKA using the recent prosthesis provided better satisfactory results. However, the risk of injury in the posterior cortex of the tibial metaphysis or remnant patella should be considered in this design modified prosthesis. Level of Evidence. Level III

Aims. We present our experience of using a metal-backed prosthesis and autologous bone graft to treat gross glenoid bone deficiency. Patients and Methods. A prospective cohort study of the first 45 shoulder arthroplasties using the SMR Axioma Trabecular Titanium (TT) metal-backed glenoid with autologous bone graft. Between May 2013 and December 2014, 45 shoulder arthroplasties were carried out in 44 patients with a mean age of 64 years (35 to 89). The indications were 23 complex primary arthroplasties, 12 to revise a hemiarthroplasty or resurfacing, five for aseptic loosening of the glenoid, and five for infection. Results. Of the 45 patients, 16 had anatomical shoulder arthroplasties (ASA) and 29 had reverse shoulder arthroplasties (RSA). Postoperatively, 43/45 patients had a CT scan. In 41 of 43 patients (95%), the glenoid peg achieved > 50% integration. In 40 of 43 cases (93%), the graft was fully or partially integrated. There were seven revisions (16%) but only four (9%) required a change of baseplate. Four (25%) of the 16 ASAs were revised for instability or cuff failure. At two-year radiological follow-up, five of the 41 cases (11%) showed some evidence of lucent lines. Conclusion. The use of a metal baseplate with a trabecular titanium surface in conjunction with autologous bone graft is a reliable method of addressing glenoid bone defects in primary and revision RSA setting in the short term. ASAs have a higher rate of complications with this technique

Antigranulocyte scintigraphy with the use of monoclonal antibodies or antibody fragments (leukoscan) is a promising diagnostic tool that has been used widely during the recent years for the establishment of prosthesis infection after total hip or knee arthroplasty. In the present study we report the Ioannina University Hospital experience in the diagnostic efficacy of leukoscan for the diagnosis of prosthesis infection in patients with total hip or knee arthroplasty. We considered all patients with suspected total hip or knee arthroplasty infection that had undergone a leukoscan examination for the diagnosis of this infection in our department during the year 2004. All patients underwent a 3-phase bone scan and a subsequent leukoscan. For the whole group of patients the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were calculated by comparison of the results of three-phase bone scan or leukoscan with the results obtained from cultures of synovial fluid obtained from articular puncture or cultures of intraoperative sampling from those patients that had undergone a revision surgery. A total of 19 patients with total joint arthroplasty (12 THA and 7 TKA) and suspected prosthesis infection were included in the study. The mean age of patients was 67 years. Twelve patients had verification of prosthesis infection in cultures. The overall sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for the three-phase bone scan were 54%, 83%, 88%, 45% and 63% respectively. On the contrary, the overall sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for leukoscan were 75%, 86%, 90%, 66% and 79%, respectively. Antigranulocyte scintigraphy with the use of monoclonal antibody fragment sulesomab (leukoscan) had good but not perfect diagnostic performance for the diagnosis of prosthesis infection in patients with total hip or knee arthroplasty

Introduction: The surgical gold standart treatment of the thumb osteoarthritis is the trapeziectomy with tendon interposition and ligament reconstruction. The trapeziometacarpal prosthesis is an option badly estimated in the literature. Between 1994 and 2001, 43 non-cimented trapeziometacarpal prosthesis ARPE® (Biomet. ™. ) was implanted by the same operator for isolated trapezio-metacarpal degenerative osteoarthritis. The minimal follow-up is 5 years. The aim of this study is to evaluate the fonction of the thumb with a 5 year-old or more trapeziometacarpal prosthesis. The technique is described and the revisions are analysed. Material and methods: 33 women and 2 men, mean age 59,4-years, were operated after failure of the conservative treatment. There are 7 lost sight (9 prosthesis) and 2 deaths (2 prosthesis). 27 other patients (32 prostheses) were examined by the author with an original revision questionnary associated to the score of DASH. The average follow up for the 25 prosthesis always implanted is 86 months. 7 revisions (16%) were necessary on average after 34 months (1 month in 10 years) : 5 for loosenning, 1 for premature dismantling and 1 for recurrent partial dislocation. 6 were treated by trapeziectomy with tendinous interposition of palmaris longus according to the technique of F.E. Jones. Results: The mobility is perfect for all patients but one. There is no tendancy for the cup or steem to sink into the bone but there is often some medial calcifications around the trapezium. Average DASH score is 27.4/100. There is no infection and only one dislocation at 1 months (reduction by closed procedure). The survival of the prosthesis is 85% in 5 years. In the first 13 months, 4 revisions is necessary. The ablation of the cup is easy but the extraction of de metacarpal still is often difficult. The scaphometacarpal height is constantly lowered (34,5 % on average). Aesthetically, 2 patients are disappointed and preferred their thumb with prosthesis. Discussion and conclusion: The prosthesis ARPE ® is an effective option in this series for the treatment of the degenerative trapeziometacarpal osteoarthritis but its radioclinic control is necessary for the first year

Since 1985 an original cementless, stainless prosthesis for C3-C7 cervical vertebral body substitution has been in use, fixed to contiguous vertebral bodies with screws. The prosthesis was employed in 151 patients, who were mostly affected by cervical metastases involving intractable pain with signs of nerve-root and/or myelon compression, using a permanent collar. The use of this kind of prosthesis allowed a easy and quick surgery with early post-surgical mobilisation of the patient without any external support. Cervical pain resolution was very evident in all patients. Cervical substitution did not affect the prognosis of tumour but allowed a better nursing and quality of life of these patients. At a follow-up of 2.5 years we have not observed any prosthesis mobilisation. In the last year some modifications were added to the prosthesis. Overall the prothesis was made of titanium, produced in two fashions, closed and open, and different lengths. The closed prosthesis is employed according to the indications of the previous prosthesis (in cases of corporectomy in neoplasms). The second one, open and empty, is filled with bone chips (autologous or etherologous) to achieve fusion with sorrounding vertebral bodies. Indications for the last type was corporectomy for discoarthrosis at two contiguous levels in patients in whom the intermediate vertebra were removed to assure a complete and safe cord decompression. The open prosthesis could also be used in burst fractures, avoiding other systems that require an anterior plate. The implantation technique presents no difficulties and can be easily incorporated into the group of standard surgical procedures for anterior interbody fusion. We have used the prosthesis in 11 cases. The new titanium prothesis was easy to handle and provided immediate stability in all cases. Clinical and radiological follow-up examinations were performed at the time of discharge from hospital, and 3 and 6 months postoperatively. The clinical outcome was good or excellent in all the cases performed. On X-rays there was no implant migration or dislocation at the last follow-up and, to date, in CT reconstruction no insufficient fusion or pseudarthrosis has been observed. We cannot report any local complication. Results were promising and encouraging at a short-term control. Follow-up will be continued

Objective: The purpose of this study is to evaluate the functional performance of patients who underwent to two different types of total knee prosthesis replacement (TKR). Methods: Kinematics and kinetics of the knee and ankle and electromyography activity of the lower limb muscles were obtained from 16 patients who underwent a TKR. 8 patients had received a fixed bearing prosthesis while the other 8 patients had received a mobile bearing prosthesis. The functional performance of the patients was evaluated using two tests, the gait and the squat. As control, 8 normal subjects, matched by age, were also evaluated. Results: During the stance phase of gait, patients with TKR showed a reduced knee extensor (internal) moment as compared to normal controls. During the squat test, patients with TKR exhibited a knee ROM that was reduced with respect to normal patients. Moreover, all patients with TKR showed a low velocity of execution of the both tests. There were no significant differences between patients who had received a fixed vs. mobile bearing prosthesis. Discussion: The results showed that after TKR, the functional performance of the patients is different from that of the normal subjects, regardless of the type of prosthesis implanted

For the treatment of malignant bone tumours in immature patients, extending prostheses are used to maintain growth in the affected limb. This new prosthesis allows the implant to be lengthened by using electromagnetic coupling that is simple and easy to use. Because of bone tumour, fourteen patients between the age of 8 and 15 years underwent bone replacement treatment and a further two patients, both male 18 and 61 years, received the same treatment to restore limb length discrepancy. These implants consisted of a telescoping shaft where the expansion is done by a power screw driven by a gearbox connected to a NdFeB magnet. This prosthesis is capable of being extended under an axial load of up to 1350N. This is in line with 76 distraction force measurements taken in 43 patients with growing prosthesis where extension was achieved by invasive procedure and where a force of up to 1513N for an extension of 6mm was recorded. Once implanted, the non-invasive prosthesis is extended by placing the limb through an external drive unit. As the drive unit is turned on, it produces a rotating magnetic field capturing the implant magnet causing it to rotate in synchronisation. At full speed, the implant grows at a rate of 0.23mm per minute. Of the sixteen patients, seven have been extended with one to its full capacity of 63mm. During extension, the patients have no sensations of vibration, heat, stretching or any other kind although the faint vibrations could be heard by placing a stethoscope on bony protrusions such as greater trochanter. At each sitting, the patients were extended by approximately 4mm during normal outpatient clinics and were able to walk as before immediately after the treatment. Patients with knee joint were functionally assessed before and after the treatment and showed approximately 10° to 15° of reduction in knee flexion/extension. This new extending mechanism in these prostheses has provided the patients a treatment, which reduces trauma infection and discomfort. The mechanism of extension is reliable and effective

In this 2-year randomised clinical trial we examined whether cemented femoral prosthesis geometry affects the pattern of strain-adaptive bone remodelling in the proximal femur after THA. 128 patients undergoing primary THA were randomised to receive a Charnley (shape-closed, no taper), Exeter (force-closed, double-tapered) or C-stem (forced-closed, triple-tapered) prosthesis. All received a cemented Charnley cup. Proximal femoral BMD change over 2 years was measured by DXA. Urine and serum samples were collected at pre-operative baseline and over 1 year post-operatively. N-telopeptides of type-I-collagen (NTX) was measured in urine as a marker of osteoclast activity and Osteocalcin (OC) in serum as a maker of osteoblast activity. Clinical outcome using the Harris and Oxford hip scores, and prosthesis migration measured using digitised radiographs (EBRA-Digital) were measured over 2 years. The baseline characteristics of the subjects in each group were similar (P> 0.05). Decreases in femoral BMD were observed over the first year for all prosthesis designs. Bone loss was greatest (14%) in the proximal medial femur (region 7). The pattern and amount of bone loss observed was similar between all prosthesis designs (P> 0.05). Transient rises in both osteoclast (NTX) and osteoblast (OC) activity also occurred over year 1, and were similar in pattern in the 3 prosthesis groups (p> 0.05). All prostheses showed migration patterns that were true to their design type and similar improvements in clinical hip scores were observed over the 2 year study. Differences in the proposed mechanism of load transfer between prosthesis and host bone in force-closed versus shape-closed femoral prosthesis designs in THA are not major determinants of prosthesis-related remodelling

SL-PLUS MIA stem (Smith & Nephew Orthopaedics AG) is a modified implant of Zweymuller type SL-PLUS standard stem (Smith & Nephew Orthopaedics AG). We constructed finite element (FE) models and analysed equivalent stresses in the femur. In addition, we measured bone mineral density (BMD) in the femur by dual-energy X-ray absorptiometry (DEXA) after THA. The purpose of this study was to investigate the equivalent stress and to compare the results of the FE analyses with changes in BMD after THA. Twenty-one patients (18 women and 3 men) who underwent primary cementless THA with SL-PLUS MIA or SL-PLUS formed the basis of this study. Eleven patients received SL-PLUS MIA and ten patients received SL-PLUS. Zones were defined according to Gruen's system (zones 1∼7). Computed-tomography (CT) images of the femur were taken before and at 1 week after THA. FE models of the femur and prosthesis were obtained from CT data by Mechanical Finder (Research Center of Computational Mechanics Inc., Tokyo, Japan), software that creates FE models showing individual bone shape and density distribution. Equivalent stresses were analysed in zones 1 to 7 and compared to the DEXA data. FE studies revealed that there was no significant difference in equivalent stress between SL-PLUS MIA and SL-PLUS. BMD was maintained after THA in zones 3, 4, and 5, whereas BMD decreased in zones 2, 6, and 7. In zone 1, BMD decreased in SL-PLUS MIA stem group by 14%, while BMD was maintained in SL-PLUS standard stem

PROBLEM

Since the COVID-19 pandemic of 2020, there has been a marked rise in the use of telemedicine to evaluate patients following total knee arthroplasty (TKA). Telemedicine is helpful to maintain patient contact, but it cannot provide objective functional TKA data. External monitoring devices can be used, but in the past have had mixed results due to patient compliance and data continuity, particularly for monitoring over numerous years. This novel stem is a translational product with an embedded sensor that can remotely monitor patient activity following TKA

Aim. According to Tsukuyama classification, late acute hematogenous prosthesis joint infections (PJI) should be treated with debridement and implant retention (DAIR). We report here a recurrent Salmonella Dublin hip prosthesis infection. Through this case, we show how a recurrence of chronic PJI may have an acute clinical presentation leading to an inadequate surgical treatment. Method. Case report. On May 2011, a 74-year-old woman with bilateral hip prostheses (implanted in 1998 (right) and 2001 (left)), was admitted to intensive care for sepsis and pain of her left hip. Blood cultures and a joint aspiration of the left hip yielded pure cultures of S.Dublin. The patient had a recent history of febrile diarrhea after consuming dubious meat. The patient underwent DAIR followed by a six-week antibiotherapy. Three years later, she presented to the emergency room for an acute onset febrile PJI of the right hip. The patient underwent DAIR of the right hip. Blood cultures, joint aspiration fluid, and all intraoperative periprosthetic tissue samples yielded S.Dublin. Colonoscopy and abdomen ultrasound were negative. The patient received two weeks of intravenous combined antibiotherapy followed by oral antibiotics for further 10 weeks. Six weeks post operatively, the surgical wound was healed and the patient walked normally. One year later, the patient was referred by her primary care practitioner for night fevers without local signs or dysfunction of her prostheses. Radioleucoscintigraphy showed right hip inflammation. Bilateral hip biopsies were nevertheless performed, yet S. Dublin was recovered solely from the right hip biopsy. A one-stage exchange of the right hip was performed. All intraoperative periprosthetic tissue samples yielded S.Dublin. A six-week-combined antibiotherapy was undertaken. One year later, the patient appeared free of infection and walked normally. Results. Whole-genome sequencing was carried out on the three patient's strains (2011/2014/2015). Their genomes differed by only six SNPs, suggesting that they derived from a single “infecting” strain. Conclusions. This is the first report of recurrent S.Dublin PJI proven by whole genome sequencing. In the absence of detectable gallbladder and/or intestinal carriage, it is most likely that S. Dublin was able to persist at the surface of prosthesis, leading to a chronic disease with recurrences occurring years after the initial episode. These recurrences were associated with a clinical acute onset of the infection, inducing an inadequate surgical treatment at the first time. A better knowledge of possible acutisation of chronic PJI by orthopedic surgeons may improve surgical management of these infections

Aim. Debridement, antibiotics and implant retention (DAIR) has become the preferred treatment in early prosthetic joint infections (PJI) and acute haematogenous PJI, but the success rates have been varying. The aim of this study was to evaluate the outcome of a high quality DAIR procedure performed according to a consistently applied surgical protocol in early PJI's and acute haematogenous PJI's in hip and knee. Methods. We performed a prospective multicentre study in 8 hospitals in Norway. A standardized DAIR protocol was used in all patients. An empirical intravenous regimen containing cloxacillin and vancomycin was given until definitive microbiological results were known. Antibiotics were given in total for 6 weeks. The primary outcome measure was infection control. Factors that could affect the outcome were also studied. Results. Out of 99 patients included, 82 were finally analysed. 68/82 patients were successfully trreated (82,9% (CI: 74,4%-90,2%)). We found that DAIR following an infected revision arthroplasty was associated with poor outcome (59%) compares to DAIR following a primary arhroplasty (89%, p=0,007). Conclusion. The success rate of a standardized DAIR-procedure with 6 weeks of antibiotic treatment was good in PJI following primary prosthesis. The success rates following revision surgery infections are poor, and other treatment options should be considered

Aim. The saddle prosthesis was originally developed for reconstruction of large acetabular defects in hip revision arthroplasty. Later on the saddle prosthesis was also used for hip reconstruction after resection of peri-acetabular tumours. In case of patient survival a long-term good hip function is required of the saddle prosthesis. The goal of this study is the measurement of long-term clinical results of saddle prosthesis after reconstruction of peri-acetabular tumours. Method. Between 1987 and 2003 a total of 17 patients were treated in the Leiden University Medical Center with saddle prosthesis after resection of peri-acetabular tumours (12 chondrosarcoma, 3 osteosarcoma, 1 malignant fibrous histiocytoma, 1 metastasis). 11 of the 17 patients died, the mean survival was 37 months (range 2-59 months), and 6 patients were still alive (follow-up 12.1 year, range 8.3–16.8 year). The outcome was measured with the SF-36 questionnaire, the Toronto Extrimity Salvage Score (TESS) and the Musculo Skeletal Tumour Society (MSTS) score. In 1 patient the saddle prosthesis was removed already after 3 months because of luxation and infection. Results. In 13 of the 17 patients the use of walking devices was known: 54% required two crutches, 38% one crutch, and 8% no walking aids. The mean hip flexion was 60 degrees (range 40-100 degrees). Local complications were seen in 14 of the 17 patients: 9 wound infections, 7 luxations, and 2 leg length discrepancies requiring additional surgery. In the 5 surviving patients the MSTS score at long-term follow up was 47%, the mean TESS score was 53%, the mean composite SF-36 physical and mental scores were 43.92 and 50.64 respectively. Conclusion. Reconstruction with saddle prosthesis after peri-acetabular tumour surgery has a high risk of complications, and poor long term functional outcome with limited flexion of the hip

1. The customary method of broaching and of knocking the prosthesis down into the neck of the femur produces an indeterminate interference fit. 2. The usual interference fit may suffer progressive breakdown under even small, steady loads. This results in a permanent relative movement between prosthesis and femur as the metal insert "beds " into the bone. 3. Modification of the usual practice by providing a clearance fit between prosthesis and femur and cementing of the metal into the bone provides a system which has been shown to be free of breakdown under steady loads up to about 450 pounds. 4. By cementing the prosthesis shaft into the femur permanent relative movement between the elements has been shown to be reduced from approximately four-hundredths of an inch per 100 pounds load to two ten-thousandths of an inch per 100 pounds load–that is, a reduction of 200 to 1

Background. Thrust plate prosthesis (TPP) is a bone conserving prosthesis in use for over thirty years. TPP is a stemless and uncemented femoral prosthesis fixed at the lateral femoral cortex with a bolt, plate and screw. This has a metal-on-metal articulation with a 28mm Metasul head and Allofit press fit acetabular cup. Our study aimed to assess the functional outcome of this prosthesis. Methods. In our institution 234 TTPs were implanted between 1995 and 2005. All patients completed a self-assessed questionnaire of Harris Hip Score at 2 months, 1 year, and then yearly. Only those who had a follow up was within the last two years were included in the analysis. 76 patients who had failed to satisfy the criteria were excluded. Of the 158 hips in the study 75 hips were in male patients and 83 were in female patients. The median age of patients was 52 years (range 15 to 82). 75 hips were on the right side and 83 on the left. All patients were operated by the senior author or a senior trainee under his supervision (seven hips). Revision of the implant or decision to revise was taken as the end point of our study. Results. The median time to follow up was 7 years (range 1 to 15). The median pre-operative hip score was 43 (range 3 to 77) which rose to 83 points (range 11 to 100) at the latest follow up. Median hip score in females improved from 39 to 82 points and in males from 52 to 85 points. Twelve patients underwent revision surgery either for infection or aseptic loosening. Conclusion. The Thrust Plate Prosthesis had a good outcome with an increase in hip score of 40 points and a median survival of 7 years

Growing prostheses have been utilised in the United Kingdom since the late 1970s. Various mechanisms have been tried, but to date all have required some form of surgical intervention. This has led to multiple hospital admissions and a large amount of resources, both in theatre time and rehabilitation. Over the last ten years the Department of Bio-Medical Engineering at University College, London, together with the Royal National Orthopaedic Hospital, Stanmore, have developed a prosthesis which does not require surgical intervention to elongate. The total cost of the development has been something in the order of £350,000.00. The design features are the power worm screw mechanism where one turn equals 1 mm of elongation, but attached to this mechanism is an epicyclic gearbox, which has been reduced in size so that it can fit in to the body of the prosthesis. The speed reduction achieved by the gear box is 13061 to 1. The mechanism is capable of withstanding an axial load of 1,350 newtons. When an external magnetic field is applied an external coil speed of 3,000 revs per minute leads to a lengthening of 0.23 mm per minute. To date the prosthesis has been inserted in three patients ages 11, 12 and 13. All were suffering from osteosarcoma of the distal femur and had previously received neo-adjuvant chemotherapy. Early elongation had been achieved in all patients without any major discomfort and without the need for either analgesia or inpatient admission. There had been no loss of range of movement in the early post-lengthening period. This new prosthesis represents a significant advance in the management of skeletal sarcomas in children

Aims: The authors reported an original technique for proximal humerus reconstruction followed tumor resection using a delta composite prosthesis. Seven patients undergoing this technique Technique: Proximal humeral resection was conducted usually. The host tendons of rotator cuff were resected; the deltoid muscle must be preserved. The glenosphere was inserted with three screws. A long humeral stem was used to provide a distal anchorage of 10 cm; this stem was cemented into the allograft and into the humerus host. The patient was immobilized in 90¡ of abduction during 6 weeks. Results: 7 patients aged 38 to 56 years, who presented a chondro-sarcoma or an osteosarcoma of the proximal humerus were enrolled in this study. The mean follow-up was 20 months (6 to 24). None patient presented with pain and the mean of active abduction was 120¡. No local or general recurrence was detected. Discussion: The Delta prosthesis of Gramon is usually used for shoulder arthritis with rotator cuff rupture. In our experience, reconstruction of the proximal humerus with composite prosthesis provides good functional results but after 3 years, a graft resorption was observed and the functional results decrease. The delta prosthesis could provide good functional results without reconstruction of the rotator cuff. In our technique, we sutured the rotator cuff to avoid dislocation. However, the glenoid þxation is incertain for a long term because its a constrained prosthesis. This technique could be used when the deltoid muscle can be preserved

We report our experience over seven years with a floating radial-head prosthesis for acute fractures of the radial head and the complications which may result from such injury. The prosthesis has an integrated articulation which allows change of position during movement of the elbow. We present the results in 12 patients with a minimum follow-up of two years. Five prostheses had been implanted shortly after injury with an average follow-up of 49 months and seven for the treatment of sequelae with an average follow-up of 43 months. All prostheses have performed well with an improved functional score (modified from Broberg and Morrey 1986). We have not experienced any of the complications previously reported with silicone radial-head replacement. Our initial results suggest that the prosthesis may be suitable for the early or delayed treatment of Mason type-III fractures and more complex injuries involving the radial head

Introduction: Inflammatory or degenerative processes of glenohumeral joint lead to pain and restriction of movements of the shoulder. As with the treatment of disabling arthritis in the other large joints, prosthetic replacement of the glenohumeral joint has gained in popularity because of its efficacy in relieving pain. Several designs for the total shoulder replacement (TSR) prostheses are currently used for the cemented and cementless implantation. The uncemented prostheses were developed in order to achieve a “biological” fixation of the implant to the adjacent bone. No survivorship data exists to compare these devices to the original TSR prostheses for cemented implantation, although this information is crucial for the decision making regarding their use. We present the long term survival rates of the Bio-Modular TSR prosthesis for uncemented implantation. Methods:The Bio-Modular TSR prosthesis was implanted in 90 patients between 1989–1994 (15 men and 75 women, mean age 61 years, range 19–92 years). This prosthesis was the first to use an anatomical, offset humeral head, based on the study on the bony anatomy of the upper humerus. The mean follow-up period was 8.8 years. Survivorship analysis, according to the method described by Murray et al. and based on Rothman’s formula for the confidence limits determination, was used for the outcome evaluation of all the prostheses studied. The criterion for failure in this series was are-operation on the shoulder with a removal of part or all of the prosthesis. Results: The ten-year cumulative survival rates of the Bio-Modular prosthesis was 71.7%. The main cause for this low survivorship rate is the low survivorship of this prosthesis among patients with primary osteoarthritis, 61.4% ten years survivorship. Conversely among the patients with rheumatoid arthritis the ten years survivorship was considerably higher (86.9%). The main cause of failure of this prosthesis was related to the glenoid component and was either due to aseptic glenoid component loosening (in 54% of the failed cases) or a failure (uncoupling) of the polyethylene bearing liner in 17% of failed cases. Furthermore about 70% of the failed cases occurred during the first four postoperative years showing an overall four years cumulative survivorship rate of 80.9%. Discussion: The survivorship data presented here indicate that the use of the Bio-Modular TSR prosthesis in patients with osteoarthritis produces less favorable results, comparing to the classical (Neer II) cemented designs. Therefore, the use of this prosthesis in patients with osteoarthritis should be reconsidered. But the higher survival of the prosthesis in the patients with rheumatoid arthritis suggests its safe use in the rheumatoid patients

Introduction. Total Elbow Arthroplasty (TEA) is recognized as an effective treatment solution for patients with rheumatoid arthritis or for traumatic conditions. Current total elbow devices can be divided into linked or unlinked design. The first design usually presents a linking element (i.e. an axle) to link together the ulnar and humeral components to stabilize the joint; the second one does not present any linkage and the stability is provided by both intrinsic design constraints and the soft tissues. Convertible modular solutions allow for an intraoperative decision to link or unlink the prosthesis; the modular connections introduce however additional risks in terms of both mechanical strength and potential fatigue and fretting phenomena that may arise not only due to low demand activities loads, but also high demand (HD) ones that could be even more detrimental. The aim of this study was to assess the strength of the modular connection between the axle and the ulnar component in a novel convertible elbow prosthesis design under simulated HD and activities of daily living (ADLs) loading. Methods. A novel convertible total elbow prosthesis (LimaCorporate, IT) comprising both ulnar and humeral components that can be linked together by means of an axle, was used. Both typical ADLs and HD torques to be applied to the axle were determined based on finite element analysis (FEA); the boundary load conditions for the FEA were determined based on kinematics analysis on real patients in previous studies. The FEA resultant moment acting on the axle junction during typical ADLs (i.e. feeding with 7.2lbs weight in hand) was 3.2Nm while for HD loads (i.e. sit to stand) was 5.7 Nm. In the experimental setup, 5 axle specimens coupled with 5 ulnar bodies through a tapered connection (5 Nm assembly torque) were fixed to a torque actuator (MTS Bionix) and submerged in a saline solution (9g/l). A moment of 3.2 Nm was applied to the axle for 5M cycles through a fixture to test it under ADLs loading. After 5M cycles, the axles were analyzed with regards to fretting behavior and then re-assembled to test them against HD loading by applying 5.7 Nm for 200K cycles (corresponding to 20 years function). Results. All 5 samples withstood all 5.2M loading cycles without any mechanical failure. At the end of 5M cycles, each axle was still stable as the measured disassembly torque was 3.96 +/−0.18 Nm. Slight signs of fretting were detected on the tapered connection after 5M cycles, however they did not compromise the mechanical connection nor the stability. Discussion and Conclusions. Currently there are no reference standards that properly define protocols for biomechanical testing of elbow prostheses. In the present study, a test to mechanically assess the strength of an axle connection under both typical ADLs and HD loads was set. The connection was able to withstand the imposed conditions. In general, testing of TEA devices should include not only standard ADLs loads but also HD loads, which could be more detrimental for the long-term survivorship. For any figures or tables, please contact authors directly

Purpose. The purpose of this study is to evaluate the midterm results of cementless revision total hip arthroplasty (THA) using Wagner Cone Prosthesis. Material and Methods. Between 1996 and 2007, 36 hips in 36 consecutive patients underwent femoral revision THA using Wagner Cone Prosthesis. Among them 28 hips were followed for more than 5 years. The mean age at revision surgery was 57 years and a mean follow-up was 7.6 years. The Paprosky classification system was used for preoperative bone loss evaluation. Clinical results were evaluated using Harris hip scores. For evaluation of the femoral component, radiolucent lines at bone-implant interfaces were evaluated and femoral component vertical subsidence was measured. Heterotopic bone formation and complications were also evaluated. Results. The mean period from 1. st. operation to revision THA was 8.0 years. For the femoral bone loss, in eleven hips bone grafting was done. For the prevention of femoral stem fracture, femoral wiring was done in 12 hips. In eighteen hips acetabular cup revision was done simultaneously and in 5 hips isolated stem revision was done. The mean Harris hip score improved from 52 to 83 at final follow-up. With respect to radiological results all femoral stems showed bone ingrowths, 3 out of 28 (10.7%) femoral stems showed subsidence more than 5 mm. Two patients needed acetabular revision for acetabular loosening during follow up period. There was one patient who complained of anterior thigh pain. One patient had recurrent dislocation and required revision surgery for soft tissue augmentation. Conclusions. We achieved favorable midterm clinical and radiological results for femoral stem revisions using Wagner cone prosthesis. This cementless femoral stem can be a good option for femoral stem revision

Introduction One of the most difficult aspects of shoulder arthroplasty is retroversion. The ideal angle is about 30 of posterior rotation of humeral head with regard to the frontal plane so that the humeral head squarely faces the glenoid surface in the resting position. The axis, lateral epicondyle- medial epicondyle is often taken as reference and serves as landmark in many arthroplasty instrumentation. [. 1. ,. 2. ]. Clinical experience has shown that estimating a 30 angle in space is definitely not easy even with the help of diverse goniometers. Methods Each operator has to put 3 prostheses with a 30 degrees retroversion according to the position of the forearm so we had proceeded to 52 putting of prostheses . The measures were made by taking into account of the humerus axis, the plan of condyles and angle of inclination of the collar, given by the angle of cutting. Three barycentres of the three humeral sections have determined the humeral axis. The condylar axis is determined from the 2 barycentres of the digitalized points on the anterior articular condylar surfaces. These 2 axis determine the frontal plane on which a reference mark R(x, y, z) is attached with Z lined up with the humeral shaft and X lined up on the condyles. Different angles could then be determined. In the sagittal plan (perpendicular in the humeral axis), the retroversion angles of the prosthesis and the angle of cutting are calculated. Results The standard deviation of the retroversion angle of the prosthesis is 14,22 which is really too high. In fact, 4 prostheses were inserted with poor retroversion (17°, 17°, 18°, 4,4°) and 20 with excessive retroversion (max =65°). This retroversion angle is not dependant on the other factors (cut angle, inclination angle...) The implant height was not taken into account. Conclusions Only 28 of the prostheses were placed in the right orientation within 20° to 40° of retroversion angle. It shows the difficulties to place a shoulder prosthesis in good position.even in standard conditions and with the standard marks

There is little evidence on the cost effectiveness of different brands of hip prostheses. We compared lifetime cost effectiveness of frequently used brands within types of prosthesis including cemented (Exeter V40 Contemporary, Exeter V40 Duration and Exeter V40 Elite Plus Ogee), cementless (Corail Pinnacle, Accolade Trident, and Taperloc Exceed) and hybrid (Exeter V40 Trilogy, Exeter V40 Trident, and CPT Trilogy). We used data from three linked English national databases to estimate the lifetime risk of revision, quality-adjusted life years (QALYs) and cost. . For women with osteoarthritis aged 70 years, the Exeter V40 Elite Plus Ogee had the lowest risk of revision (5.9% revision risk, 9.0 QALYs) and the CPT Trilogy had the highest QALYs (10.9% revision risk, 9.3 QALYs). Compared with the Corail Pinnacle (9.3% revision risk, 9.22 QALYs), the most commonly used brand, and assuming a willingness-to-pay of £20 000 per QALY gain, the CPT Trilogy is most cost effective, with an incremental net monetary benefit of £876. Differences in cost effectiveness between the hybrid CPT Trilogy and Exeter V40 Trident and the cementless Corail Pinnacle and Taperloc Exceed were small, and a cautious interpretation is required, given the limitations of the available information. However, it is unlikely that cemented brands are among the most cost effective. Similar patterns of results were observed for men and other ages. The gain in quality of life after total hip arthroplasty, rather than the risk of revision, was the main driver of cost effectiveness. Cite this article: Bone Joint J 2015;97-B:762–70

Purpose: We report our results of revision procedures for severe acetabular loosening with saddle prostheses. The series concerned six patients, mean age 67 years age range 58–82 years, who initially presented rheumatoid disease (n=3), degenerative hip disease (n=3, one secondary to trauma), and radiation-induced hip disease (n=1). These patients had undergone one to three procedures for reconstruction with a bone graft and metal implants. Material and methods: Failure was the indication for salvage with a saddle prosthesis due to massive loss of acetabular bone stock, complicated in five cases by an unstable hemipelvis due to transverse nonunion. An allograft was screw fixed in the iliac wing in two cases to stabilise the saddle prosthesis. Weight bearing was allowed early after surgery in all cases except two. The hip was immobilised in four cases for three to six weeks in a bermuda cast or with traction (n=4). Follow-up was 2 to 5 years. Results: There was only one complication: stress fracture of the iliac bone at two years which did not heal. Bone graft with ostheosynthesis was proposed. Pain relief was nearly total in all cases. Four patients could walk without crutches and two walked with two crutches or an ambulator due to associated disease or alar fracture. The fixation was at 60 – 95° with abduction at 10–30°. All patients were satisfied and two felt the result was very superior to simple ablation of the prosthesis which they had experienced. Radiograpically, there was no evidence of ascension of the saddle but the risk remains at this short follow-up due to the rates described in the literature. One major migration was observed as was one stress fracture of a weak iliac bone which required removal of the implant. Discussion: This difficult technique provides a better result and thus would be indicated for young patients able to sustain the intervention. It would be logical to associate a supporting bone graft on the iliac bone to prevent stress fracture and migration of the saddle. The saddle prosthesis appears to be the last resort after failure or insufficient results after prior reconstruction. The leading cause of failure is nonunion with hemipelvis mobility. This suggests the intervention should be considered before reaching this stage of well tolerated ace-tabular loosening

The prosthesis anchored to the vertebral body by a large central keel has inherent risk of angular mismatching between vertebral endplate and prosthesis endplate at large lordotic segment such as L5-S1. Theoretically, these angular mismatching can be considered to cause several problems such as segmental hyperlordosis, anterior positioning of upper prosthesis, posterior prosthetic edge subsidence, decreased ROM and poor clinical outcome. The purpose of this study is to assess whether angular mismatching between vertebral endplate and prosthesis endplate in lumbar total disc replacement (L-TDR) with ProDisc-L influence on radiological and clinical outcomes. We evaluated 64 levels of 56 patients who were implanted with ProDisc-L from 2002 to 2006. Prosthetic levels were 38 levels of L4–5, and 26 levels of L5-S1 (8 patients had 2 level-operations of L4–5 and L5-S1). Mean follow-up was 25.6 (12–49) months. Angle of mismatching between lower endplate of upper vertebral body and upper prosthetic plate, segmental flexion/extension ROM, segmental lordosis angle at extension, distance from the posterior wall of vertebral body to posterior prosthetic edge were measured in the radiographs. Clinically VAS and ODI were evaluated. Angular mismatching between upper vertebra and prosthesis of L4–5 and L5-S1 was 1.6° (range, 0–6°) and 5.6° (0–13°) (p< 0.001) respectively, at final follow-up. Angular mismatching at immediate postoperative radiographs (2.3° in L4–5 and 4.9° in L5-S1) and at final follow-up was not significantly different (p=0.324 in L4–5, 0.620 in L5-S1). Mean segmental ROM of operated levels was 10.6° (4–22°) in L4–5 and 6.1° (2–13°) in L5-S1(p< 0.001). Mean segmental ROM, mean segmental lordosis angle, and mean distance from posterior margin of vertebral body to posterior end of prosthesis in L5-S1 were 6.8° (4–13°), 12.8° (8–17°), 3.8mm (1–6mm) in cases with angular mismatching less than 10°, and 4.6° (2–7°), 21.3° (19–25°), 6.0 mm (2–8mm) in that of 10° or more (p=0.024, < 0.001, 0.039), respectively. In L4–5 angular mismatching of more than 5° were only 2 cases without statistical significance. Clinical outcomes, VAS and ODI, of L4–5 compared with that of L5-S1 and of angular mismatching less than 10° with that of 10° or more in L5-S1 did not have difference between them (p> 0.05). Angular mismatching between lower endplate of upper vertebra with upper prosthesis endplate is more common in L5-S1 than in L4–5. L-TDR at the most lordotic level, L5-S1, implantation of upper prosthesis with mismatched angle seems to be the causes of lessened segmental ROM, increased segmental lordosis, and anterior positioning of prosthesis

In the present study we describe the clinical results of the Scientific Hip Prosthesis® (SHP). With the goal of smoothening cement-bone interface stress peaks, the SHP was developed using shape optimization algorithms together with finite element modelling techniques. The resulting shape and cement stresses are seen in Figure 1. The introduction of the SHP prosthesis was performed in a stepwise fashion including a RSA study performed by Nivbrant et al. 1. RSA studies for prosthetic types that are in long-term use are of great value in predicting the survivorship related to the migration rate and pattern for that specific type of prosthesis. If a stem in a patient shows a much higher migration rate than the typical one, the stem may be identified as at high-risk for early loosening. The study of Nivbrant et al. 1. revealed unexpectedly high migration values and it was stated that the SHP stem was not the preferred stem to use despite the good Harris Hip Score and Pain score at two years follow-up. In the present study the clinical results of a single surgeon study consisting of 171 hips with a follow-up of 5–12 years were evaluated. The mean follow-up was 8.2 years (5.0–12.0). The survival rate was 98.8% at ten years follow-up for aseptic loosening of the stem. The mean Harris Hip Score at 10 year follow-up was 89.2 ± 7.5. This study therefore indicates that a new prosthetic design may function clinically rather well, despite the relatively high migration rates which have been reported. In case of a RSA study with a new prosthesis it may not be so evident what the expected “typical” migration rate or pattern is. So in order to predict early loosening the typical migration rate has to be known. Perhaps typical migration rates can be established using standardized cadaver migration experiments or computer simulation models techniques. Since these standardized tools are currently not available, the prediction of clinical survival of new prosthetic components remains a challenging task and the interpretation of migration rates with new designs should be considered with much caution

When managing malignant long bone tumours in skeletally immature patients it is desirable, after resection, to reconstruct with a prosthesis that can be lengthened at appropriate intervals to keep pace with growth of the contralateral side. In an attempt to avoid multiple surgical procedures to achieve such lengthening we have recently developed a prosthesis that can be lengthened non-invasively. Purpose of study: To look at our early experience with the use of non-invasive growing femoral prostheses. Methods: Between November 2002 and February 2004 the prosthesis was implanted in 6 patients (3 males and 3 females) with a diagnosis of osteosarcoma. The patients were aged between 9 and 14 years (mean 11.5 years) at the time of surgery. Patients were lengthened at appropriate intervals and the process was monitored with scanograms. The prosthesis contains a magnet that is connected to gears that drive the extending mechanism. The patients’ limb is placed into a coil and the principle of electromagnetic induction coupling is used to achieve lengthening. Total degree of lengthening to date was recorded for each patient together with the range of knee movement and any complications that occurred. Patients were functionally evaluated at their last follow-up visit using the Musculoskeletal Tumour Society (MSTS) Scoring System. Results: To date patients have been lengthened by an average of 18mm (8–48mm). The mean amount of knee flexion is 125 degrees. The mean MSTS score is 18 (16–21). There have been two complications; one patient developed patella subluxation during the lengthening programme and one patient has required serial casting to treat a flexion deformity of 25 degrees. Conclusions: We have been encouraged by our early results with this prosthesis and have been able to demonstrate that the technology works reliably in vivo. We are continuing to use this prosthesis in skeletally immature patients

We present data relating to the Bryan disc arthroplasty for the treatment of cervical spondylosis in 46 patients. Patients with either radiculopathy or myelopathy had a cervical discectomy followed by implantation of a cervical disc prosthesis. Patients were reviewed at six weeks, six months and one year and assessment included three outcome measures, a visual analogue scale (VAS), the short form 36 (SF-36) and the neck disability index (NDI). The results were categorised according to a modification of Odom’s criteria. Radiological evaluation, by an independent radiologist, sought evidence of movement, stability and subsidence of the prosthesis. A highly significant difference was found for all three outcome measurements, comparing the pre-operative with the post-operative values: VAS (Z = 6.42, p < 0.0001), SF-36 (mental component) (Z = −5.02, p < 0.0001), SF-36 (physical component) (Z = −5.00, p < 0.0001) and NDI (Z = 7.03, p < 0.0001). The Bryan cervical disc prosthesis seems reliable and safe in the treatment of patients with cervical spondylosis

Introduction: The distorted anatomy in Developmental Dysplasia of the Hip (DDH) makes a total hip arthroplasty (THA) a challenging procedure. The purpose of the current study is to report the midterm results after uncemented primary hip arthroplasty using S ROM prosthesis in a prospective series of patients with hip dysplasia. Methods: We performed 22 uncemented total hip replacements using S ROM prosthesis in 21 (12 female and 9 male) patients with hip dysplasia. The means age at the time of hip surgery was 41.8 (22 to 64) years. The mean follow-up was 6.3 (3.8 to 9.6) years. In 9 (40.9%) patients the operative treatment of DDH was performed during the early childhood (femoral osteotomy in 6 and pelvic osteotomy in 3). All patients were evaluated clinically and radiologically. The femoral head displacement prior to THA surgery was classified according to Crowe at al. classification (4 hips were type1, 2 type2, 10 type3 and 6 type 4). Results: The average Harris Hip Score improved from 29.48 to 72.76 (44 to 99) and the average Oxford hip score is 31.22 (12 to 47). The range of flexion is 60°–120° (average 83.23) and abduction is 10°–40°(average 22.94). None of the hips has dislocated. Radiolucent lines were noted around the femoral stem in one case. None of the cases have developed osteolysis around femoral prosthesis. In one patient (4.5%), revision hip surgery was done for aseptic loosening of cemented acetabular cup. Discussion: The midterm results of total hip replacement in DDH using S ROM uncemented prosthesis are promising. We recommend this modular prosthesis for hip replacement in dysplastic hips

The purpose of this study is to evaluate the results of revision surgery in the treatment failed TKR with the TCP III like prosthesis. Materials & Methods: Between 1985 till May 2001, 116 failed knees were managed. 91 underwent complete revision, 18 were arthrodesed, 6 underwent patella revision only and 1 arthrolysis. Among the complete revisions: 45 were due to mechanical failure (loosening, wear or instability) 29 for infection and 17 for painful or stiff knee. In 81 of them the implanted prosthesis was TCP III or CCK and were evaluated in this study. 33 were males and 58 females. The average age at revision was 72 years. Most of the cases were performed by the senior author. All cases were osteoarthritic except one which was rheumatoid. The distribution of TCP III like prosthesis was as follows: 47 were TCP III, 33 were CCK and 2 dual. The infected cases were treated whether by one stage or two stage surgery. Patella was not resurfaced but reshaped if patella bone stock was not adequate. Results: Nine patients died and 14 patients could not be traced in the last follow-up. The average follow up was around 6 years (range of 6 months to 16 years). As compared to preoperative situation almost all of the patients were on the overall subjectively satisfied. The preop HSS score was poor for all the patients. The average postop HSS score was 82 for mechanical failure, 76 for infection and 77 for painful knee. One infected knee got reinfected after 3 years. Three cases had to be revised for the second time to a rotating hinge prosthesis: 2 due to instability and one due to loosening. Discussion: The TCP III like prosthesis proved in our hands to be a relatively successful implant in revision knee surgery. The new modular CCK design is quite an improvement over the TCP III design and is more versatile in allowing restoration of previous anatomy and joint line. The obvious advantage of this implant are its immediate inherent stability combined with a reproducible normal valgus alignment. The results were best in the treatment of failed knee due to mechanical failure

A retrospective study was performed to evaluate the results of proximal humeral replacement prosthesis in the oncologic setting. Following tumour resection and implantation of the prosthesis, the soft tissues around the shoulder were either sutured directly to the prosthesis (three cases) or a dacron capsuloplasty was performed (five cases). Emphasis was on assessing shoulder instability. Eight patients were availaible for the study. Three patients needed to be re-operated for instability. Average instability rating on the ASES visual analog scale was 3,2/10. We conclude the prosthetic instability can be a significant problem for these patients. The purpose of this study was to assess the results of oncologic proximal humeral prosthesis with a focus on shoulder instability. Following limb-salvage procedures of the shoulder girdle, reconstruction of the soft-tissues to obtain prosthetic stability can be a major challenge. A retrospective study of patients that underwent oncologic shoulder replacement. Results were evaluated using the SF-36 questionnaire, the MSTS 1987 and 1993 scales as well as the Standardized ASES method for assessement of shoulder function, including the visual analog scale for instability. Nine patients were still living and eight of them were able to participate in this study. Average follow-up was seventy-three months. In five cases a capsuloplasty was performed using a dacron vascular prosthesis. In the remaining cases the capsule, rotator cuff or deltoid were sutured directly to the prosthesis. Average instability rating was 3,2/10 using the visual analog scale. Three patients were reoperated for instability. Two had a failed soft tissue repair with inferior dislocation of the prosthesis and one had recurrent anterior dislocation. Average MSTS 1987 and 1993 scores were 19,9 and 18,9 respectively. SF-36 scores were significantly lower than Canadian standards in the physical functioning, role physical and mental health domains. Our data show a significant rate of instability related problems following prosthetic replacement of the proximal humerus in cases of limb salvage. We were unable to indentify specific strategies to prevent this. Further research is needed to determine optimal soft tissue reconstruction for oncologic procedure about the shoulder