Aims. The aim of this study was to describe implant and patient-reported outcome in patients with a unilateral transfemoral amputation (TFA) treated with a bone-anchored, transcutaneous prosthesis. Methods. In this cohort study, all patients with a unilateral TFA treated with the Osseointegrated Prostheses for the Rehabilitation of Amputees (OPRA) implant system in Sahlgrenska University Hospital, Gothenburg, Sweden, between January 1999 and December 2017 were included. The cohort comprised 111 patients (78 male (70%)), with a mean age 45 years (17 to 70). The main reason for amputation was trauma in 75 (68%) and tumours in 23 (21%). Patients answered the Questionnaire for Persons with Transfemoral Amputation (Q-TFA) before treatment and at two, five, seven, ten, and 15 years’ follow-up. A prosthetic activity grade was assigned to each patient at each timepoint. All mechanical complications, defined as fracture, bending, or wear to any part of the implant system resulting in removal or change, were recorded. Results. The Q-TFA scores at two, five, seven, and ten years showed significantly more prosthetic use, better mobility, fewer problems, and an improved global situation, compared with baseline. The survival rate of the osseointegrated implant part (the fixture) was 89% and 72% after seven and 15 years, respectively. A total of 61 patients (55%) had mechanical complications (mean 3.3 (SD 5.76)), resulting in exchange of the percutaneous implant parts. There was a positive relationship between a higher activity grade and the number of mechanical complications. Conclusion. Compared with before treatment, the patient-reported outcome was significantly better and remained so over time. Although osseointegration and the ability to transfer loads over a 15-year period have been demonstrated, a large number of mechanical failures in the external implant parts were found. Since these were related to higher activity, restrictions in activity and improvements to the mechanical properties of the implant system are required. Cite this article: Bone Joint J 2020;102-B(1):55–63

Introduction. Unicompartmental arthroplasty is still a controversial issue in knee replacement, mainly due to a marked variation in published survival rates of the implants. The aim of this study was to analyse possible risk factors for revision following Oxford unicompartmental knee arthroplasties (OUKA). Material and methods. Since 1997 data for all patients with primary and revision knee arthroplasties performed in our department have been stored in a database. Selected for the present study was all primary OUKA performed in the period 1997–2006 as well as any revision following these operations until the end of 2008. We got information from The National Health Register and the CPR register about any revision performed at other institutions and date in case of death. Primary OUKA were grouped in three categories according to the experience of the surgeon: 1 for operation done by a surgeon who had performed less than 20 OUKA, 2 for operation by a surgeon who had performed 20–40, and 3 for operation by a surgeon who had performed more than 40. Risk of revision was analysed by Cox regression. Revisions due to pain as the only reason were excluded from the analyses. Age and gender of the patients, previous surgical intervention, operation time, and the experience of the surgeon were included as possible risk factors in the analysis. Results. 445 primary Oxford knee arthroplasties were included. These were followed by 46 revisions. The indications for the revisions were: aseptic loosening 16 knees, progression of the osteoarthritis to the lateral compartment 7 knees, dislocation of the polyethylene meniscus 5 knees, varus-valgus instability 3 knees, fracture of the medial tibia condyle 3 knees, collision of the polyethylene meniscus and the femur condyle 1 knee, and pain as the only reason 11 knees. Age and gender of the patients as well as previous surgical intervention in the knee in question were not correlated to the risk of revision. Operation time was correlated to risk of revision with decreasing risk with increasing operation time (p=0,001). The experience of the surgeon was also correlated to risk of revision with decreasing risk with increasing experience (p=0,02). The 6 years survival rate for an experienced surgeon using an operation time at 90 min. or more was 97,5 % compared to a survival rate at 78,7 % for an inexperienced surgeon with an operation time less than 90 min. Conclusion. OUKA performed by an inexperienced surgeon and OUKA performed with short operation time had marked reduced survival rates. This seems to be an essential information to institutions performing OUKA

Aims

Despite multiple trials and case series on hip hemiarthroplasty designs, guidance is still lacking on which implant to use. One particularly deficient area is long-term outcomes. We present over 1,000 consecutive cemented Thompson’s hemiarthroplasties over a ten-year period, recording all accessible patient and implant outcomes.

Aims. Displaced, comminuted acetabular fractures in the elderly are increasingly common, but there is no consensus on whether they should be treated non-surgically, surgically with open reduction and internal fixation (ORIF), or with acute total hip arthroplasty (THA). A combination of ORIF and acute THA, an approach called ’combined hip procedure’ (CHP), has been advocated and our aim was to compare the outcome after CHP or ORIF alone. Patients and Methods. A total of 27 patients with similar acetabular fractures (severe acetabular impaction with or without concomitant femoral head injury) with a mean age of 72.2 years (50 to 89) were prospectively followed for a minimum of two years. In all, 14 were treated with ORIF alone and 13 were treated with a CHP. Hip joint and patient survival were estimated. Operating times, blood loss, radiological outcomes, and patient-reported outcomes were assessed. Results. No patient in the CHP group required further hip surgery, giving THA a survival rate of 100% (95% confidence interval (CI) 100 to 100) after three years, compared with 28.6% hip joint survival in the ORIF group (95% CI 12.5 to 65.4; p = 0.001). No dislocations or deep infections occurred in the CHP group. No patient died within the first year after index surgery, but patient survival was lower in the CHP group after three years. There were no relevant differences in patient-reported outcomes. Conclusion. The CHP confers a considerably reduced need of further surgery when compared with ORIF alone in elderly patients with complex acetabular fractures. These findings encourage both further use of, and larger prospective studies on, the CHP. Cite this article: Bone Joint J 2019;101-B:478–483

The primary aim of this study was to compare the knee specific functional outcome of partial compared with total knee replacement (TKR) for the management of patellofemoral osteoarthritis. Fifty-four consecutive Avon patellofemoral replacements were identified and propensity score matched to a group of 54 patients undergoing a TKR with patella resurfacing for patellofemoral osteoarthritis. The Oxford knee score (OKS), the Short Form (SF-) 12 and patient satisfaction were collected (mean follow up 9.2 years). Survival was defined by revision or intention to revise. There was no significant difference in the OKS (p>0.60) or SF-12 (p>0.28) between the groups. The TKR group was significantly less likely to be satisfied with their knee (95.1% versus 78.3%, OR 0.18, p=0.03). Length of stay was significantly (p=0.008) shorter for the Avon group (difference 1.8 days, 95% CI 0.4 to 3.2). The 10 year survival for the Avon group was 92.3% (95% CI 87.1 to 97.5) and for the TKR group was 100% (95% CI 93.8 to 100). There was no statistical difference in the survival rate (Log Rank p=0.10). The Avon patellofemoral replacement have a shorter length of stay with a functional outcome and satisfaction rate that is equal to that of TKR. The benefits of the Avon need to be balanced against the increased rate of revision when compared with TKR

The primary aim was to assess survival of the opening wedge high tibial osteotomy (HTO) for medial compartment osteoarthritis. The secondary aim was to identify independent predictors of early (before 12 years) conversion to total knee arthroplasty (TKA). During the 18-year period (1994–2011) 111 opening wedge HTO were performed at the study centre. Mean patient age was 45 years (range 18–68) and the majority were male (84%). Mean follow-up was 12 (range 6–21) years. Failure was defined as conversion to TKA. Kaplan-Meier, Cox regression and receiver operating curve (ROC) analyses were performed. Forty (36%) HTO failed at a mean follow-up of 6.3 (range 1–15) years. The five-year survival rate was 84% (95% confidence interval (CI) 82.6–85.4), 10-year rate 65% (95% CI 63.5–66.5) and 15-year rate 55% (95% CI 53.3–56.7). Cox regression analysis identified older age (p<0.001) and female gender (hazard ratio (HR) 2.37, 95% CI 1.06–5.33, p=0.04) as independent predictors of failure. ROC analysis identified a threshold age of 47 years above which the risk of failure increased significantly (area under curve 0.72, 95% CI 0.62–0.81, p<0.001). Cox regression analysis, adjusting for covariates, identified a significantly greater (HR 2.49, 95% CI 1.26–4.91, p=0.01) risk of failure in patients aged 47 years old or more. The risk of early conversion to TKA after an opening wedge HTO is significantly increased in female patients and those older than 47 years old. These risk factors should be considered pre-operatively and discussed with patients when planning surgical intervention for isolated medial compartment osteoarthritis

Background. Computer-assisted navigation systems for total knee arthroplasty (TKA) were introduced to improve implantation accuracy and to optimize ligament balancing. Several comparative studies in the literature confirmed an effect on the component position and other studies could not confirm these results. For ligament balancing most studies found no significant influence on the clinical outcome using a navigation system for TKA. In the literature there were no reports of mid-term results after navigated TKA. With our study we wanted to show if the use of a navigation system for TKA will have an influence on the component's position and on the clinical results at 5-year follow up. Methods. We enrolled 200 patients in a prospective randomized study with a minimum follow up of 5 years. 100 TKA were operated on without using a navigation system (Group A) and 100 surgeries (Group B) were done with computer assistance. Radiological investigation by standard radiographs including a long-leg X-ray was performed with a follow up rate in Group A of 86.2% versus 80.2% in Group B. We measured the mechanical axis of the leg, lateral distal femoral angel (LDFA), medial proximal tibial angle (MPTA), tibial slope and the alpha-angle of the patella. Clinical investigation was performed with a follow up rate in Group A of 85.7% versus 79.8% in Group B including the parameters for the range of motion (ROM), ligament balancing, anterior drawer test, feeling of instability, anterior knee pain, effusion, WOMAC Score, Insall Score and HSS Knee Score. Results. In both groups there was no aseptic loosening or difference in TKA survival rate (Group A 95.4% versus Group B 98.85% 5-year survival rate, p = 0.368). With the navigation technique the mechanical axis of the limb in the frontal plane was improved (p = 0.015; Group B: 1.67 ° ± 1.6° versus 2,44 ° ± 2.2 ° in Group A). 90% of the Group B and 81% of the Group A were within 3 ° varus/valgus deformity of the mechanical axis of the limb (p = 0.157). The accuracy of tibial slope was higher in the Group B (p = 0.001). More patients of the Group B (95% versus 79%) were within a deviation of 3 °, −7 ° tibial slope (p = 0.007). The mean deviation of 90 ° LDFA was higher (p = 0.034) in the Group A (1.89 ° versus 1.36 ° in Group B). Mean deviation of 90 ° MPTA, mean MPTA, mean LDFA and patella alpha angle were similar in both groups (p 0.253). There was no difference in ROM, ligament balancing, anterior drawer test, anterior knee pain or feeling of instability (p 0.058). Insall Knee Score total (181 Group A/191 Group B) and HSS Knee Score total (91 Group A/93 Group B) was higher with the navigated procedure in Group B (p 0.026). WOMAC total and HSS grades were similar in both groups (p 0.070). Conclusions. The accuracy of the mechanical axis of the limb and the tibial slope was higher with the navigated procedure. TKA survival rate and clinical outcomes were similar in both groups at 5-year follow up

Metastatic osteosarcoma is seen in 10-20% of patients at initial presentation with the lung the most common site of metastasis. Historically, prognosis has been poor. We studied trends in survival in our small developed nation and aimed to identify correlations between the survival rate and three factors: newer chemotherapy, advances in radiological imaging and a more aggressive approach adopted by cardiothoracic surgeons for lung metastases. Our national bone tumour registry was used to identify patients at the age of 18 or under, who presented with metastatic disease at initial diagnosis between 1933 and 2006. There were 30 patients identified. Kaplan-Meier analysis was used to determine survival rates and univariate analysis was performed using the Cox regression proportional hazards model. Median survival has improved over the last 50 years; highlighted by the ‘Kotz’ eras demonstrating incremental improvement with more effective chemotherapy agents (p=0.004), and a current 5-year survival of 16%. Aggressive primary and metastatic surgery also show improving trends in survival. Three patients have survived beyond five years. The introduction of computerised tomography scanning has led to an increase in the prevalence of metastases at initial diagnosis. Metastatic osteosarcoma remains with a very poor prognostic factor, however, aggressive management has been shown to prolong survival

The concept of stainless steel dual mobility cups in total hip arthroplasty has demonstrated very low long-term instability rates and a 98% survival rate after 12 years. We systematically implanted titanium alloy acetabular cups during a one year period. The purpose of our retrospective study was to report the 18-year clinical outcome data in a homogeneous and continuous series of 103 primary total hip replacements after implantation of a cementless titanium cup. All patients were implanted with NOVAE Ti (SERF) cups made of titanium alloy combined with a retentive polyethylene liner and a 22.2 mm cobalt chrome prosthetic head. Mean patient age at the time of surgery was 53 years. All patients were clinically and radiographically evaluated. The overall 18-year actuarial cup survival rate with a 95% confidence interval was 87.4%. At last follow-up, there was no evidence of implant instability whereas acetabular aseptic loosening was reported in one case and high wear of the retentive liner in 9. The results of this investigation confirmed the long-term stability of dual-mobility implants. The main limitation of this system was early wear of the polyethylene liner in contact with the titanium metal back and reaction with third body along with loss of liner retentivity. In our study, titanium demonstrated favourable osteointegration properties but poor tribologic characteristics, therefore suggesting its interest at the bone-cup interface only

To our knowledge in medial unicompartmental knee arthroplasty (UKA) no study has specifically assessed the difference in outcome between matched gender groups. Previous unmatched gender studies have indicated more favourable results for women. Method. 2 groups of 40 of either sex was determined sufficient power for significant difference. These consecutively were matched with both the pre-operative clinical and radiological findings. Minimum follow up of 2 years, mean follow-up 5.9 years. Mean age at operation was 71 years. Results. In both groups, the mean IKS knee and function scores improved significantly (p< 0.001) post operatively. There were no significant differences were between the 2 groups. In both groups mean preoperative flexion was 130 degrees and remained unchanged at final follow-up. No significant differences in preoperative and postoperative axial alignment and in the number of radiolucent lines, between groups. With component size used there was a significant difference (p < 0.001) between the 2 groups. However the size of the femoral or tibial implant used was significantly related (p< 0.001) to patient height for both sexes. Radiolucent lines were more frequent on the tibial component, but were considered stable with none progressing. No revisions for component failure. 1 patient in each group developed lateral compartment degenerative change. Male group; one conversion to TKA for undiagnosed pain, three patients underwent reoperation without changing the implant. Female group; no implants were revised, and two patients required a reoperation. Kaplan-Meier 5-year survival rate of 93.46% (84.8; 100) for men and100% for women. The survival rate difference is not significant (p=0.28). Conclusion. These results suggest that there is no difference in outcome between sexes and that gender should not enter into the selection criteria for UKA. It also suggests that height and not gender is important to predict the appropriate UKA components

Background. Modular endoprostheses today represent a standard treatment option in the management of musculoskeletal tumors of the lower extremities. Long-term results of these reconstructions, however, are often limited by the course of the underlying disease. We therefore report our experiences in cancer patients with megaprostheses of the lower limb after a minimum of 15 years. Materials and Methods. 62 patients, 34 men and 28 women, with a mean age of 26 years (median, 20; range, 6–83) were included in this investigation with a mean follow-up of 230 months (median, 228; range, 180–342). Endoprosthetic reconstructions of the proximal femur (11), the distal femur (28), the total femur (2) or the proximal tibia (21) were indicated for osteosarcoma (43), chondrosarcoma (5), malignant fibrous histiocytoma (3) or other tumors (11). All patients have received either a KMFTR (22) or a HMRS (40) modular prosthesis; 23 patients had a muscle flap, 14 had a fibular transposition osteotomy and 4 have received an artificial LARS ligament for soft-tissue reconstruction. Results. 7 patients (11.3%) died throughout the follow-up period, but none succumbed to primary disease. One patient (1.6%) developed a local recurrence after 31 months that was resected. Overall, 56 patients (90.3%) underwent revision of their prosthesis; 50 (80.7%) had multiple revisions up to a maximum of 12 operations (mean, 3 per patient). The median overall prosthetic survival to first revision was 40 months; the corresponding 5-, 10- and 15-year survival rates were 35.5%, 14.5% and 12.9%, respectively. 3 patients (5.4%) had an infection, 8 (14.3%) had a soft-tissue related failure, 30 (53.6%) had a mechanical or structural failure and 15 (26.8%) had an aseptic loosening. The 15-year survival rates of these respective endpoints were 87.1% for infection, 79.0% for soft-tissue related failure, 32.3% for mechanical or structural failure and 56.5% for aseptic loosening. 59 patients (95.2%) have retained their prosthesis; 2 patients (3.2%) underwent secondary amputation due to an irresolvable complication, another one (1.6%) for a second malignancy. Conclusion. Modular prosthetic reconstructions of the lower extremities have a high revision rate in the long-term, primarily due to mechanical failures. Given that patients survive their malignant disease the rate of secondary implant removal, however, tends to be low, providing satisfactory function and body integrity. Further advances in implant design, soft tissue management and infection prophylaxis are required to reduce revision rates

INTRODUCTION. Computer-aided systems have been developed recently in order to improve the precision of implantation of unicompartmental knee replacement (UKR). Minimal invasive techniques may decrease the surgical trauma related to the prosthesis implantation, but there might be a concern about the potential for a loss of accuracy. Mobile bearing prostheses have been developed to decrease the risk of polyethylene wear, but are technically more demanding. Navigation might help to compensate for these difficulties. We wanted to combine the theoretical advantages of the three different techniques by developing a navigated, minimal invasive, mobile bearing unicompartmental knee prosthesis. MATERIAL AND METHODS. 160 patients have been operated on at our institution with this system. The 81 patients with more than 2 year follow-up have been re-examined. Complications have been recorded. The clinical results have been analyzed according to the Knee Society Scoring System. The subjective results have been analyzed with the Oxford Knee Questionnaire. The accuracy of implantation has been analyzed on post-operative antero-posterior and lateral long leg X-rays. The 2-year survival rate has been calculated. RESULTS. We observed 8 complications related to the implant or the operative technique: 2 cases of meniscus instability (1 revision to TKR, 1 bearing exchange); 2 cases of tibia loosening (revised to TKR), 2 cases of femoral loosening (revised to TKR), 1 case of lateral disease progression (revised to TKR), 1 case of unexplained pain syndrome (revised to TKR). The mean Knee Score was 93 points, 44% had the maximum of 100 points, and only 10% have less than 85 points. The mean pain score was 48 points/50. The mean flexion angle was 128°, and 60% had at least 130° of knee flexion. The mean Function Score was 97 points, 84% have the maximum of 100 points, and only 5% had less than 85 points. The mean Oxford Knee Questionnaire score was 19 points (best result: 12 points, worst result: 60 points). Expected limb axis correction was obtained in 77% of the cases. 62% of the cases had an optimally implanted prosthesis for all studied criteria. The 2-year survival rate was 97%. DISCUSSION. Most of the revision cases were related to technical difficulties during the development phase. Fixation of the implant has been improved, and some imprecise steps of the software have been corrected. Since these changes occurred, no severe early complication related to implant or software has been observed. The current implant is considered reliable, and the current minimal invasive navigated technique is considered reliable as well

Aims

Proximal humeral fractures (PHFs) are common. There is increasing evidence that most of these fractures should be treated conservatively. However, recent studies have shown an increase in use of operative treatment. The aim of this study was to identify the trends in the incidence and methods of treatment of PHFs in Finland.

The surgical treatment of unicompartmental knee osteoarthritis remains controversial. This study aims to compare the medium-term outcomes of age and gender matched patients treated with unicompartmental knee replacement (UKR) and total knee replacement (TKR). We retrospectively reviewed pain, function and total knee society scores (KSS) for every UKR and age and gender matched TKR in NHS Tayside, with up to 10 years prospective data from Tayside Arthroplasty Audit Group. KSS was compared at 1, 3 and 5 years. Medical complications and joint revision were identified. Kaplan-Meier with revision as end-point was used for implants survival analysis. 602 UKRs were implanted between 2001 and 2013. Preoperative KSS for pain and total scores were not significantly different between UKRs and TKRs whereas preoperative function score was significantly better for UKRs. Function scores remained significantly better in UKRs from preoperative until 3 years follow up. Further analysis revealed no statistically significant difference in the change of function scores in both groups over time. There was a trend for TKRs to perform better than UKRs in pain scores. Total KSS for both groups were not significantly different at any point of the 5-year study. Fewer medical complications were reported in the UKR group. Kaplan-Meier analysis showed a survival rate of 93.7% in UKRs and of 97% in TKRs (Log rank p-value = 0.012). The revision rate for UKR was twice as much as TKR. The theoretical advantages of UKR are not borne out by the findings in this study other than immediate postoperative complications

A review of current literature describes varying 10-year survival rates for the Oxford Unicompartmental Knee Replacement (Biomet Orthopedics Inc, Warsaw, Ind). Application of rigorous indications and meticulous surgical technique are two factors considered to reduce revision rates. A retrospective case-note review was conducted for 96 patients (128 knees) aged 42–89 (mean 57) who had an Oxford unicompartmental knee replacement for medial compartment osteoarthritis between January 2000 and January 2011. All procedures were performed, or directly supervised, by one 5 surgeons. The aim of the study was to ascertain the rate of revision to bicompartmental knee replacement and any associated contributory factors. Of the 128 unicompartmental knees, 10.9% were revised to either mobile- or fixed-bearing total knee replacements due to septic (0.5%) and aseptic (1.5%) loosening, patello-femoral pain (3.9%), periprosthetic fracture (0.8%) and bearing dislocation (3.1%). Of those knees requiring revision, mean patient age was 73 years, 50% had wound complications and 42% were performed by senior trainees. All patients had intact ACL and medial osteoarthritis. Mean time to revision was 2.7 years. In conclusion, revision of the unicompartmental knee was related to patient age > 65 years and early post-operative complications; grade of operating surgeon had little apparent effect

Between July 2000 and December 2002, 263 consecutive patients across 5 surgical centers underwent to a revision surgery of a failed acetabular component in which TM acetabular components were used. There were 150 women and 113 men with a mean age of 69.5 years. The indication for acetabular revision was aseptic loosening in 186 cases (70.7%). Clinical evaluations were performed using the Harris hip score, the WOMAC and UCLA activity scale. Implant and screw position, polyethylene wear, radiolucent lines, gaps, and osteolysis were assessed. Preoperatively, acetabular bone deficiency was categorized using the classification of Paprosky et al. Statistical analysis was performed using nonparametric correlations. Standard life table was constructed, and the survival rate was calculated by means of Kaplan-Meier method. The overall mean follow-up was 73.6 months (range, 60–84 months), and no patient was lost to follow-up. The preoperative HHS rating improved from a mean of 43.6 ± 11.4 before revision, to a mean of 82.1 ± 10.7. None of the patients was re-revised for loosening. The cumulative prosthesis survival was 99.2% at 5 years. There was no correlation found between the various degrees of acetabular bony defect and the magnitude of clinical results (independent of pre-revision Paprosky grade). The use of component augments allowed us to minimize the volume of morsellized allograft used for defect repair. TM acetabular component demonstrates promising midterm results similar to those reported by other authors

Background. No study compared the clinical results of the posterior-stabilized mobile-bearing knee with those of nonposterior-stabilized mobile-bearing knee in the same patients. The purpose of this study was to examine whether the clinical and radiographic results, range of motion, patients satisfaction, and complication rates would be better in the knees with a posterior-stabilized mobile-bearing knee than in the knees with a nonposterior-stabilized mobile-bearing knee. Methods. One hundred and fourteen patients (mean age, 67.9 years) received a nonposterior-stabilized mobile-bearing knee prosthesis in one knee and a posterior-stabilized mobile-bearing knee prosthesis in the contralateral knee. Seven patients were men, and 107 were women. At the time of each follow-up (mean, 7.3 years; range, seven to 7.6 years), the patients were assessed clinically and radiographically. Results. The mean postoperative Knee Society knee score (95 points versus 96 points, p=0.176), Hospital for Special Surgery knee score (92 points versus 93 points, p=0.077), and Western Ontario and McMaster University Osteoarthritis score (21 versus 20 points, p=0.785) were similar between the two group. At the final follow-up, the average range of motion was 27.7° (range, 70° to 150°) in the knees with a nonposterior stabilized mobile-bearing prosthesis and it was 132° (range, 90 to 150 °) in the knees with a posterior-stabilized mobile-bearing prosthesis. Complication rates (2.6% versus 1.8%) were similar between the two groups. The estimated survival rate was 97.4% at eight years with an overall revision rate of 2.6% (three of 114 knees) in the nonposterior-stabilized mobile-bearing prosthesis group and 98.2% at eight years with an overall revision rate of 1.8% (two of 114 knees) in the posterior-stabilized mobile-bearing prosthesis group. Conclusions. After a minimum duration of follow-up of seven years, we found no significant differences between the two groups with regard to the clinical and radiographic results, or patient satisfaction, or complication rate. However, the posterior-stabilized mobile-bearing prosthesis group had a greater range of knee motion than the nonposterior-stabilized mobile-bearing prosthesis group

Over the last few decades, the All-Poly Monoblock Tibia has been relegated to a minimum use in the major healthcare systems of the western world. The main reason for this has been the perception that this tibial component is inferior in its ability to withstand stresses. This perception originated and subsequently gained ground, due to certain historical reasons, leading to the widespread use of the modular metal-backed tibial component despite a higher cost. The recent economic downturn has enforced even the rich western healthcare systems to look for cost-effective solutions. The author works in India, where the society is still highly price-sensitive and takes value for money very seriously. Further, the routine ADL of the Indian population requires them to adopt high flexion postures such as cross-legged sitting and squatting. The author has used the All-Poly Tibia extensively, which is the most economical of tibial components. Further, he has developed a surgical technique which has resulted in his patients achieving high flexion (greater than 135 degrees) in more than 75% cases. This paper presents the 10 year results of a series of 500 cases of Primary TKR in which the All-Poly Monoblock Tibia had been used. All the patients had cross-legged sitting activity as part of their ADL, thus presumably generating significant pressures on the joint surfaces. Of the original 500 cases, we could follow up 434 cases. We report a 96% survival rate of the implant in this series. There was not a single aseptic plastic failure. The revisions required were due to infection, peri-prosthetic fracture, and instability. The message being conveyed in this paper is that the All-Poly Tibia is a very cost-effective solution in routine Primary TKRs, and is able to deliver excellent long-term results even in high stress situations like cross-legged sitting activity. It would offer a huge cost savings to the healthcare system if the Orthopaedic Surgeons start using this implant more frequently

The use of a total hip arthroplasty with alumina on alumina bearing couple should limit the risk of wear and secondary osteolysis. From June 1999 to December 2002, we have realised a continuous series of 265 ABGII cementless THA with Alumina bearing. The average age was 58 years (22–78 years). The main causes were osteoarthritis (81%) and osteonecrosis (13%). The operation was performed through a posterior standard approach. In all cases, an anatomic cementless ABG II stem and an acetabular cementless ABG II cup were implanted. The bearing couple was always Alumina Biolox Forte with a 28 mm femoral head in 99% of cases. To date, 12 patients died and 17 patients were lost to follow up (6.4%). 224 patients (232 hips) had a regular clinical and radiological follow-up. The mean follow up was 8.5 years (5–11 years). 9 patients were revised for septic loosening (4cases), femoral fracture (4 cases) and inveterate dislocation (1 case). There was no aseptic loosening. The overall survival rate at more than 10 years is 96.6%. We deplore 2 cases of postoperative dislocation. In this series, we did not observe any breakage of ceramic implant. The clinical and functional outcome is good and stable over time with an average PMA score at 17.6 and an average Harris score at 97.3. 16 patients reported at least one or more episode of abnormal noise “Squeaking” type (6%). It is most often a mild noise and it occurs in a static bending position. This noise disappeared with time in 10 cases. It never necessitated a prosthetic revision. The radiological control does not show any wear. There is no evidence of acetabular or femoral osteolysis. The radiological implant fixation according to the Engh and ARA criteria was good and stable in all cases. This series demonstrate that the implantation of an anatomic cementless HA arthroplasty with an alumina bearing in a young and active patient prevents the risk of wear and osteolysis and improves durability over time. The use of a 28 mm head does not increase the risk of instability and we did not observe failure of the ceramic implants

Introduction. Unicompartmental knee arthroplasty (UKA) in patients with isolated medial osteoarthritis of the knee is nowadays a standard procedure with good results, especially with the minimally-invasive approach. However, the survival rate of the unicompartmental knee prostheses is inferior to that of total knee prostheses. Therefore, further studying of UKA is still necessary. In most mobile bearing designs the femoral component has a spherical surface and therefore its positioning is not crucial. The role of the tibial slope in UKA has not been investigated so far. The manufacturers recommend tibial slopes with values between 10° positive slope and 5° negative slope. Most surgeons try to reconstruct the anatomical slope with a high failure by measuring the slope on x-rays. The aim of this study was to investigate the influence of the tibial slope on the wear rate of a medial UKA. Materials and methods. In vitro wear simulation of medial mobile bearing unicompartmental knee prosthesis with a spherical femoral surface (Univation ®) was performed with a customized four-station servo-hydraulic knee wear simulator (EndoLab GmbH, Thansau, Germany) reproducing exactly the walking cycle as specified in ISO 14243–1:2002(E). The tibial tray was inserted with 2 different medial tibial slopes: 0°, 8° (n=3 for each group). The lateral tibial slope of the space-holder was not changed (0° for every group). We performed a total of 5 million cycles for every different slope, the gravimetric wear rate was determined gravimetrically using an analytical balance every 500 000 cycles according to the ISO 14243–2. Results. The wear rate in the 0° slope group was 3.46±0.59 mg/million cycles, and in the 8° slope group it was 0.99±0.42 mg/million cycles. The difference between the 0° tibial slope group and the 8° tibial slope group was highly significant (p<0.01, alternate t-test). Discussion. An increase of the tibial slope leads to a reduced wear rate in a mobile bearing UKA. Therefore, a higher tibial slope should be recommended for mobile bearing UKA. However, the influence on the ligaments has to be considered as a higher tibial slope leads to an increased strain on the anterior cruciate ligament. This influences needs to be investigated in further studies before a definite optimal range for the tibial slope can be recommended