Aims. Rotating-hinge knee prostheses are commonly used to reconstruct the distal femur after resection of a tumour, despite the projected long-term burden of reoperation due to complications. Few studies have examined the factors that influence their failure and none, to our knowledge, have used competing risk models to do so. The purpose of this study was to determine the risk factors for failure of a rotating-hinge knee distal femoral arthroplasty using the Fine-Gray competing risk model. Methods. We retrospectively reviewed 209 consecutive patients who, between 1991 and 2016, had undergone resection of the distal femur for tumour and reconstruction using a rotating-hinge knee prosthesis. The study endpoint was failure of the prosthesis, defined as removal of the femoral component, the tibial component, or the bone-implant fixation; major revision (exchange of the femoral component, tibial component, or the bone-implant fixation); or amputation. Results. Multivariate Fine-Gray regression analyses revealed different hazards for each Henderson failure mode: percentage of femoral resection (p = 0.001) and extent of quadriceps muscle resection (p = 0.005) for overall prosthetic failure; extent of quadriceps muscle resection (p = 0.002) and fixation of femoral component (p = 0.011) for type 2 failure (aseptic loosening); age (p = 0.009) and percentage of femoral resection (p = 0.019) for type 3 failure (mechanical failure); and type of joint resection (p = 0.037) for type 4 (infection) were independent predictors. A bone stem ratio of > 2.5 reliably predicted aseptic loosening. Conclusion. We identified independent risk factors for overall and cause-specific prosthetic failure after rotating-hinge knee distal femoral arthroplasty using a competing risk Fine-Gray model. A bone stem ratio > 2.5 reliably predicts aseptic loosening. An accurate knowledge of the risks of distal femoral arthroplasty after resection for tumour assists surgical planning and managing patient expectations. Cite this article: Bone Joint J 2021;103-B(8):1405–1413

Purpose: Prosthetic arthroplasty is the most common method of reconstruction of segmental bone defects following resection of bone sarcomas about the knee. The purpose of this study was to determine the survivorship of the reconstructions in short- and long-term follow-up. Methods: A retrospective study was performed on all patients diagnosed with a bone sarcoma between 1984 and 1995 who were treated with a limb-sparing osteoarticular resection and rotating hinge prosthetic knee arthroplasty. Prosthetic survival was calculated with endpoints of analysis based on any event, any prosthesis-related event and aseptic loosening of the prosthesis, which led to prosthetic revision, removal or limb amputation. Results: A total of 154 reconstructions were performed involving the distal femur (n=111) and proximal tibia (n=43). The median resection length was 155 mm (105–250mm) for the distal femur and 117 mm (85–150 mm) for the proximal tibia. All implants were fixed with polymethylmethacrylate cement. Early complications (within one year postoperatively) developed in fewer than 2 % of patients. Aseptic loosening accounted for the majority of events resulting in prosthetic failures (distal femur = 17 [median failure 34 mos]; proximal tibia = 10 [median failure 100 mos]). Polyethylene bushing wear was observed in seven patients (median time to replacement = 156 months). Conclusion: The early outcome of prosthetic arthroplasty was extremely favorable supporting this method of reconstruction following excision of high-grade bone sarcomas about the knee. Long-term survival of these prostheses is suboptimal and can be anticipated to be poor for the proximal tibia. Aseptic loosening continues to be the primary cause of prosthetic failure about the knee

Introduction. Implant malalignment is an important predictor of prosthetic failure following total knee arthroplasty (TKA). The purpose of this study was to determine the incidence of outliers for common alignment targets and the impact of surgeon volume and experience on the accuracy of implant alignment with current generation manual instrumentation. Methods. This study was a retrospective, multi-center, radiographic analysis of 1675 consecutive primary uncomplicated TKAs from seven surgeons at three academic and state-funded centers in the US and UK. Surgeons were categorized as “high-volume” (≥50 TKAs/year) and “high-experience” (≥5 years post-fellowship). Femorotibial, tibial varus/valgus, and posterior tibial slope angles were digitally measured using postoperative radiographs. Femorotibial (<2° or >8° valgus), tibial (> ±3° deviation from the neutral axis), and tibial slope (<0° or >7° of flexion for cruciate retaining, <0° or >5° of flexion for posterior stabilized) angle outliers were identified. The proportion of outliers among surgeons in each subgroup was compared. Results. When comparing high-and low-volume surgeons, the proportion of femorotibial (12% vs. 19%, p <0.0001), posterior slope (17% vs. 28%, p <0.0001), and total outliers (12% vs. 19%, p <0.0001) was significantly lower in the high-volume group. Furthermore, the proportion of knees with well-aligned implants in all three measurements (69% vs. 53%, p <0.0001) was significantly higher in the high-volume group. When comparing high-and low-experience surgeons, the proportion of femorotibial (14% vs. 17%, p = 0.046), tibial (9% vs. 6%, p = 0.030), posterior slope (19% vs. 26%, p <0.0001), and total outliers (14% vs. 17%, p = 0.006) was higher in the low-volume group. Furthermore, the proportion of knees with well-aligned implants in all three measurements (64% vs. 58%, p = 0.008) was significantly higher in the high-experience group. Conclusions. Low surgeon volume and experience predispose to implant malalignment following TKA, with surgical volume bearing a greater influence on alignment accuracy. Even among high volume, high experience surgeons, outliers in at least one standard alignment target occur in over 30% of cases with current standard instrumentation

Aims

This study compares the re-revision rate and mortality following septic and aseptic revision hip arthroplasty (rTHA) in registry data, and compares the outcomes to previously reported data.

Aims

To review the evidence and reach consensus on recommendations for follow-up after total hip and knee arthroplasty.

Background. Fractures of the femoral component are well reported complications that present a challenging task in revision total hip arthroplasty. Albeit being uncommon, with an incidence of 0.23–11%, the consequences can be devastating. Its extraction being a demanding undertaking that is potentially detrimental to the remaining host bone. Several techniques have been described to address this complex issue prior to revision: drilling of the exposed part of the femoral stem and attaching a threaded extraction device, surface undercutting with an extraction device wedged in, femoral trephine techniques, creation of a femoral cortical window, an extended femoral osteotomy procedure, as well as extraction by means of retrograde nail impaction. Here we present the modified technique we employed in the revision of a failed cementless extensively porous coated femoral component that had fractured at the neck-stem interface. Technique. The proximal femoral component was visualized and an orthopedic burr and a femoral osteotome employed surrounding the component. Utilizing a Midas Rex® MR7 drill with its metal cutting attachment, a circular recess was created in the shoulder of the femoral component. This facilitated the application of the distal end of a universal slap hammer. The component was retrieved successfully with no associated bone loss negating the need for a femoral osteotomy. Discussion. Revision hip arthroplasty is a perplexing field where unpredictable prosthetic failures require innovation to tackle the unique problems encountered. Our method allows a safe and efficient alternative in retrieving femoral components with no associated complications

Introduction. Augmented glenoid implants provide a new avenue to correct glenoid bone loss and can possibly reconcile current prosthetic failures and improve long-term performance. Biomechanical implant studies have suggested benefits from augmented glenoid components but limited evidence exists on optimal design of these augmented glenoid components. The aim of this study was to use integrated kinematic finite element analysis (FEA) model to evaluate the optimal augmented glenoid design based on biomechanical performance in extreme conditions for failure. Materials and Methods. Computer aided design software (CAD) models of two different commercially available augmented glenoid designs - wedge (Equinox®, Exactech, Inc.) and step (Steptech®, Depuy Synthes) were created per precise manufacturer's dimensions and sizes of the implants. Using FE modeling, these implants were virtually implanted to correct 20° of glenoid retroversion. Two glenohumeral radial mismatches (RM) (3.5/4mm and 10 mm) were evaluated for joint stability and implant fixation to simulate high risk conditions for failure. The following variables were recorded: glenohumeral force ratio, relative micromotion (distraction, translation and compression), and stress on the implant and at the cement mantle interface. Results. The wedged and step designs showed similar force ratio measurements with both RM [(wedge (3.5 mm: 0.69; 10 mm: 0.7) and step (4 mm: 0.72; 10 mm: 0.75)]. Surrogate for micromotion was a combination of distraction, translation and compression. As radial mismatch increased, both implants showed less distraction [wedge design (3.5 mm: 0.042 mm; 10mm: 0.030 mm); step design (4 mm: 0.04 mm; 10 mm: 0.027 mm)]. As radial mismatch increased, both implants showed more translation [wedge design (3.5 mm: 0.058 mm; 10mm: 0.062 mm); step design (4 mm: 0.023 mm; 10 mm: 0.063 mm)]. During compression measurements, the different designs did not follow the same pattern as their conformity setting changed. The wedge one decreased as radial mismatch increased, (at 3.5mm: 0.18 mm; at 10 mm: 0.10 mm) and the step design increased as its radial mismatch increased (at 3.5 mm: 0.19 mm; at 10 mm: 0.25 mm). Quantitatively, the step design showed higher risk of implant instability and loosening. As radial mismatch increased, the stress level on the backside of the implant increased as opposed to the stress levels on the cement mantle which decreased for both designs as the radial mismatch increased [wedged (3.5 mm: 2.9 MPa; 10mm: 2.6 MPa); step (3.5 mm: 4.4 MPa; 10 mm: 4.1 MPa)]. In this situation, the risk of loosening was higher for the step designwhich exceeded the endurance limit of the cement material (4 MPa). Discussion. Implant loosening and wear are associated with increased micromotion and high stress levels. Based on our FEA model, overall increased radial mismatch has an advantage of providing higher glenohumeral stability but not without tradeoffs, such as higher implant and cement mantle stress levels, and micromotion increasing the risk of implant loosening, failure or fracture over time, leading to poorer clinical outcomes and higher revision rates, especially when considering a step augmented glenoid design

Aims

The proximal tibia (PT) is the anatomical site most frequently affected by primary bone tumours after the distal femur. Reconstruction of the PT remains challenging because of the poor soft-tissue cover and the need to reconstruct the extensor mechanism. Reconstructive techniques include implantation of massive endoprosthesis (megaprosthesis), osteoarticular allografts (OAs), or allograft-prosthesis composites (APCs).

Aim. In patients with bone sarcoma, placing mega prostheses in the proximal tibia is associated with high rates of infection. In studies with small numbers of patients and short follow-up periods, silver-coated mega prostheses have been reported to lead to reduced infection rates. To the best of our knowledge, this study is the largest one that has compared the infection rates with titanium versus silver-coated mega prostheses in patients treated for sarcomas in the proximal tibia. Method. The infection rate in 98 patients with sarcoma or giant cell tumour in the proximal tibia who underwent placement of a titanium (n = 42) or silver-coated (n = 56) mega prosthesis. *. was assessed, along with the treatments administered for any infection. Results. As the primary end point of the study, the rates of infection were 16.7% in the titanium group and 8.9% in the silver group, resulting in 5-year prosthesis survival rates of 90% in the silver group and 84% in the titanium group. Overall, seven of 56 patients in the silver group (12.5%) developed periprosthetic infection. Two patients became infected after revision surgery due to mechanical failure of the prosthesis. In the titanium group, one patient developed a periprosthetic infection after revision surgery (which was carried out in 50% of patients) due to a mechanical prosthetic failure, leading to an overall infection rate of 19.0% (eight of 42). Overall, nine of 12 (75%) periprosthetic infections in the two groups occurred within the first 2 years postoperatively, if later revision surgery due to mechanical failure was not necessary. Whereas three of the eight patients in the titanium group (37.5%) ultimately had to undergo amputation due to infected proximal tibia replacement, these mutilating surgical procedures were necessary in the silver group in only one patient (14.3%). In the titanium group, two-stage revision surgery with a temporary antibiotic-impregnated cement spacer was ultimately successful in four of eight patients (50.0%), but this procedure was necessary in only one patient in the silver group (14.3%). Conclusions. The use of silver-coated prostheses reduced the infection rate in a relatively large and homogeneous group of patients. In addition, less aggressive treatment of infection was possible in the group with silver-coated prostheses

Ceramic-on-ceramic (CoC) total hip arthroplasty (THA) can produce articular noise during the normal activities, generating discomfort to the patient. THA noise has to be investigated also as a potential predictor and a clinical sign of prosthetic failure. An observational study has been carried out to characterize the noise in CoC cementless THA, and to analyze the related factors. A total of 46 patients with noisy hip have been enrolled in 38 months, within the follow-up protocol normally applied for the early diagnosis of ceramic liner fracture [1]. Noise recording was based on a high-quality audible recorder (mod. LS 3, Olympus, Japan) and a portable ultrasonic transducer (mod USB AE 1ch, PAC, USA). The sensors for noise recording were applied to the hip of the patient during a sequence of repeatable motorial activities (forward and backward walking, squat, sit in a chair, flexion and extension of the leg). Sessions were also video-recorded to associate the noise emission to the specific movements. Each noise event was initially identified by the operator and therefore classified by comparison to the spectral characteristics (duration, intensity and frequency) of the main noise types. Number and spectral characteristics of noise events were obtained and correlated to the factors describing the clinical status of the patient, the surgical approach, the prosthetic device implanted. The study investigated also the noise as a sign of implant failure, by comparison with the total number of implants failed in the cohort during the study. We observed three types of noise with the main spectral characteristics in agreement to the literature: clicking, squeaking and popping. Among the identified types of noise, squeaking showed the longest duration and the highest amplitude. The 63% of hip presented the emission of just one type of noise, while the remaining a mix of types. The movement with the highest presence of noise was walking, followed by squat. Correlation was found between the noise type and the dimension of the ceramic head (p<0.001), with the sizes of 32 mm more affected by squeaking that the smaller one. Squeaking appeared before during the follow-up than the other types of noise. The 35% (16/46) of the noisy hips were revised during the study. Among the revised hips, the 81% (13/16) were affected by impingement and/or severe damage of the prosthetic components. The antiversion of the cup (p=0.008), the presence of debris in the synovial fluid (p=0.021) and the average frequency of squeaking (p=0.006) were significant predictors for the revision, but it has to be mentioned that the squeaking data was obtained on a small subset of revised patients. Ultrasonic analysis did not show significant correlations. The study presented and validated an experimental procedure to analyze noisy hips in clinical trials. Noise is confirmed to be a significant parameter in the follow-up evaluation of ceramic THA

Pain following total hip arthroplasty is a relatively rare event. Several series place the incidence of some degree of pain post THA at approximately 5%. A systematic approach to determining etiology will direct treatment. Hip pain can be categorised as:. Extrinsic to the Hip. –. Spine +/− radiculopathy. –. Vascular disease. –. Metabolic (Paget's). –. Malignancy. Intrinsic to the Hip. Intracapsular/Implant. Loosening. Sepsis. Prosthetic failure. Osteolysis. Instability. Thigh pain. Stem tip pain. Hypersensitivity/ALVAL. Extracapsular. Iliopsoas tendonitis. Snapping Hip. Trochanter problems (bursitis). Heterotopic ossification. A full history and appropriate physical exam will direct the clinician. The use of routine radiographs, blood tests, and special tests (i.e., blood metal ions, advanced imaging techniques) will be discussed I detail

Introduction. The development of new megaprosthesis for the treatment of large bone defects has offered important opportunities to orthopedic oncologic surgeons for the replacement of skeletal segments such as the long bones of the upper and lower limbs and the relative joints. Our experience, treating non union and severe bone loss, has brought us, sometimes, to be confronted with the reality of some failures after unsuccessful attempts to reconstruct. Faced with certain radiological and / or clinical drastic situations we wanted to apply the principles of Biological Chamber and oncologic surgery with megaprosthetic replacement solutions. We implanted megaprosthesis with either 1 step or 2 steps (previous antibiotated spacer) technique depending on the septic patient conditions. The aim of this study is to retrospectively evaluate both clinical and radiological outcomes in patients underwented to a lower limb megaprosthesis implant and complications were recorded. Materials and Methods. In total, we treated 58 patients with megaprosthesis mono-and bi-articular subdivided as follows: proximal femur, distal femur, proximal tibia and total femur. The mean follow-up of patients is about 24 months (5 yrs max, min 6 months) with clinical and serial radiographic revaluations with standard methods (X-ray in 45 days, 3–6-12-18-24 months) as well as monitoring of blood parameters of inflammation for at least 2 months. Results. Despite the follow up average is not so long, the first patients have now reached five years of monitoring and in all cases we have had encouraging clinical results with good articulation of the segments, no somato-sensory or motorial defict and acceptable functional recovery. During surgery and, even more, in the pre-operative planning much attention should be given to the evaluation of the extensor apparatus preserving it and, when necessary, reinforcing it with tendon substitutes. Discussion. Megaprosthesis in traumatic and prosthetic failures can therefore be considered, in extreme cases appropriately selected, as a solution available to the orthopedic surgeon? In oncological surgery the opportunity to regive a function, although not ad integrum, to the patient is certainly an element of great fascination for the surgeon and an opportunity for the patient. Unfortunately, the high mortality associated with this disease does not allow us to have long-term follow-up. This then creates a lack of certainty about the survival of this type of prosthesis and the medium and long-term complications that may occur. Nevertheless, the patients treated by us should be considered as a oncologic patient, not because of the disease but for the limited therapeutic options available. Conclusions. We can consider megaprosthesis as a valuable opportunity to restore functionality to patients who are, despite themselves, to deal with highly disabling diseases

Aims

The aim of this study was to investigate the feasibility of application of a 3D-printed megaprosthesis with hemiarthroplasty design for defects of the distal humerus or proximal ulna following tumour resection.

Introduction. Up to 2% of total knee arthroplasties (TKA) are still complicated by infection. This leads to dissatisfied patients with poor function, and has far-reaching social and economic consequences. The challenge in these cases is the eradication of infection, the restoration of full function and the prevention of recurrence. We report the outcome of prosthesis sparing early aggressive debridement in the acutely infected TKA. Methods. We studied 29 consecutive patients referred with acutely infected TKA (18 primaries, 11 revisions) which occurred within 6 weeks of the index operation or of haematogenous spread. Microbiology confirmed bacterial colonisation in all cases with 20 early post-operative infections and 9 cases of acute haematogenous spread. All patients underwent aggressive open debridement, a thorough synovectomy and a change of insert. Antibiotics were continued until inflammatory markers and the plasma albumin concentration returned to within normal limits. Results. Three patients required multiple washouts. 8 patients needed a two stage revision. 21 patients returned to their expected functional level without removal of the implants and with no radiographic evidence of prosthetic failure. At a minimum 2 years follow-up, we had a 72% infection control rate. The outcome was significantly better in patients treated in the first 120 hours after presentation. Conclusion. Our data suggests that there is a role for early aggressive open debridement in acute infections after TKA with an excellent chance of prosthesis salvage

Introduction. Up to 2% of total hip arthroplasties (THA) are still complicated by infection. This leads to dissatisfied patients with poor function, and has far-reaching social and economic consequences. The challenge in these cases is the eradication of infection, the restoration of full function and the prevention of recurrence. We report the outcome of early aggressive debridement in the acutely infected THA. Methods. We studied 28 consecutive patients referred with acutely infected THA (18 primaries, 10 revisions) which occurred within 6 weeks of the index operation or of haematogenous spread between 1999 and 2006. Microbiology confirmed bacterial colonisation in all cases with 20 early post-operative infections and 8 cases of acute haematogenous spread. Patients with a cemented THA underwent aggressive open debridement, a thorough synovectomy and exchange of all mobile parts. Uncemented THA were treated as a single stage revision with removal of all implants, aggressive debridement and re-implantation of new prosthesis. Antibiotics were continued in all cases until inflammatory markers and the plasma albumin concentration returned to within normal limits. Results. Ten patients required multiple washouts. 7 patients needed a two stage revision. 21 patients returned to their expected functional level without removal of the implants and with no radiographic evidence of prosthetic failure. At a minimum 2 years follow-up, we had a 75% infection control rate. The outcome was significantly better in patients treated in the first 120 hours after presentation. Discussion and Conclusion. Our data suggests that there is a role for early aggressive open debridement in acute infections after THA with an excellent chance of eradicating infection

The objective of this study was to compare the results of two consecutive series of patients with either intra-medullary uncemented stems (UCS) distal femoral endoprosthetic replacement or the Compress. ®. (CMP) distal femoral implant. Patients were divided into two groups: those who received UCS prosthesis (Group-1: 54 patients) and those who received CMP prosthesis (Group-2: 42 patients).The most frequent diagnosis was osteosarcoma. Age and gender were similar both groups. In Group-1, at a mean follow-up of 144 months, 37 prostheses were still in place. The overall Kaplan-Meier prosthetic survival rates were 79% at five and 62 % at ten years. Most of failures were long term complications. Aseptic loosening was the primary cause of late prosthetic failure. On Cox regression analysis, prosthetic stem diameter under 13mm was a significant negative prognostic factor for prosthetic survival (p=0.016). In Group-2, at a mean follow-up of 84 months, 36 prostheses were still in place. The overall rate of CMP prosthesis survival was 86% at 5 years. All complications were during the first postoperative year, being femoral fracture the main revision cause. The patients who retained the prosthesis had mainly good or excellent MSTS functional results in both groups

Introduction: Up to 2% of total knee arthroplasties (TKA) are still complicated by infection. This leads to dissatisfied patients with poor function, and has far-reaching social and economic consequences. The challenge in these cases is the eradication of infection, the restoration of full function and the prevention of recurrence. We report the outcome of prosthesis sparing early aggressive debridement in the acutely infected TKA. Methods: We studied 29 consecutive patients referred with acutely infected TKA (18 primaries, 11 revisions) which occurred within 6 weeks of the index operation or of haematogenous spread. Microbiology confirmed bacterial colonization in all cases with 20 early postoperative infections and 9 cases of acute haematogenous spread. All patients underwent aggressive open debridement, a thorough synovectomy and a change of insert. Antibiotics were continued until inflammatory markers and the plasma albumin concentration returned to within normal limits. Results: Three patients required multiple washouts. 8 patients needed a two stage revision. 21 patients returned to their expected functional level without removal of the implants and with no radiographic evidence of prosthetic failure. At a minimum 2 years follow-up, we had a 72% infection control rate. The outcome was significantly better in patients treated in the first 120 hours after presentation. Discussion and Conclusion: Our data suggests that there is a role for early aggressive open debridement in acute infections after TKA with an excellent chance of prosthesis salvage

Compression testing of cadaver specimens showed that excision of the radial head allowed proximal radial displacement. The insertion of a metallic radial head restored normal mechanics, while a silicone rubber implant did not. We reviewed 31 of 36 comminuted fractures of the radial head, 21 associated with dislocation or ulnar fracture, which had been treated by primary replacement with a Vitallium prosthesis. At a mean follow-up of 4.5 years, there was reliable restoration of stability and prevention of proximal radial migration. There had been no dislocations or prosthetic failures, but two implants had been removed for loosening. The prosthesis is recommended for use as a spacer to stabilise the elbow after severe injuries while the soft tissues heal

We assessed 46 Syme’s amputees attending our prosthetic clinics in terms of the clinical and radiological condition of their stumps, their level of function and problems with the prosthesis. Twenty-five were compared with a matching group of 25 transtibial amputees in regard to activity, function and prosthetic behaviour. Function was similar in the two groups, but Syme’s amputees had a higher incidence of prosthetic failure. Overall, Syme’s amputees were pleased with their prostheses and their function. Childhood amputations were associated with fewer long-term problems in terms of function and stump problems. Syme’s amputation is indicated for congenital foot deformities, fibular hemimelia and severe injury to the foot as long as the heel pad remains viable

Increased concentrations of metal ions after metal-on-metal resurfacing arthroplasty of the hip remain a concern. Although there has been no proven link to long-term health problems or early prosthetic failure, variables associated with high metal ion concentrations should be identified and, if possible, corrected. Our study provides data on metal ion levels from a series of 76 consecutive patients (76 hips) after resurfacing arthroplasty with the Articular Surface Replacement. Chromium and cobalt ion concentrations in the whole blood of patients with smaller (≤ 51 mm) femoral components were significantly higher than in those with the larger (≥ 53 mm) components (p < 0.01). Ion concentrations in the former group were significantly related to the inclination (p = 0.01) and anteversion (p = 0.01) of the acetabular component. The same relationships were not significant in the patients with larger femoral components (p = 0.61 and p = 0.49, respectively). Accurate positioning of the acetabular component intra-operatively is essential in order to reduce the concentration of metal ions in the blood after hip resurfacing arthroplasty with the Articular Surface Replacement implant