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Background The Medial Rotation Knee (MRK) has one of the lowest revision rates of total knee replacement designs in the National Joint Registry. While survival is one metric of performance of implants, patient-reported outcomes, combined with clinical and radiological evaluation, allow more complete analysis. We report the five-year results of a prospective, multi-centre surveillance study of the MRK. Methods A 16-surgeon, three-centre series of 520 total knee replacements were performed in 486 patients, comprising 182 males and 304 females. The mean age was 70.3 years (46–96) and BMI 29.5 kg/m2 (18–57). Study subjects were given questionnaires pre-operatively, at six months, and annually thereafter. Clinical and radiological reviews were scheduled pre-operatively, at six months, three and five years. Results At five years, 395 of the original 486 patients (427 of 520 knees) remained under active review. Twenty-six patients (27 knees) had withdrawn, 44 patients/knees had died and one was excluded. Thirteen patients (14 knees) were lost to follow-up, but were not revised. Seven knees were revised, equating to a survival probability of 98.6% at five years. There were significant improvements in mean Oxford Knee Score (21.23–35.79), EQ-5D (0.440–0.694) and Knee Society Score (Knee 43.00–83.97; Function 49.45–71.39). Of the radiographs available for evaluation, radiolucency was identified in 25 knees (14.6%) with one case of osteolysis of the tibial component. Conclusion In addition to excellent survivorship, mid-term patient-reported, clinical and radiological results at five years are satisfactory, and consistent with other medial pivot designs. more...

AimsShort-stemmed femoral implants have been used for total hip arthroplasty (THA) in young and active patients to conserve bone, provide physiological loading, and reduce the incidence of thigh pain. Only short- to mid-term results have been presented and there have been concerns regarding component malalignment, incorrect sizing, and subsidence. This systematic review reports clinical and radiological outcomes, complications, revision rates, and implant survival in THA using short-stemmed femoral components.Materials and MethodsA literature review was performed using the EMBASE, Medline, and Cochrane databases. Strict inclusion and exclusion criteria were used to identify studies reporting clinical and radiological follow-up for short-stemmed hip arthroplasties.ResultsA total of 28 studies were eligible for inclusion. This included 5322 hips in 4657 patients with a mean age of 59 years (13 to 94). The mean follow-up was 6.1 years (0.5 to 20). The mean Harris Hip Score improved from 46 (0 to 100) to 92 (39 to 100). The mean Oxford Hip Score improved from 25 (2 to 42.5) to 35 (12.4 to 48). The mean Western Ontario & McMaster Universities Osteoarthritis Index improved from 54 (2 to 95) to 22 (0 to 98). Components were aligned in a neutral coronal alignment in up to 90.9% of cases. A total of 15 studies reported component survivorship, which was 98.6% (92% to 100%) at a mean follow-up of 12.1 years.ConclusionShort-stemmed femoral implants show similar improvement in clinical and radiological outcomes compared with conventional length implants. Only mid-term survivorship, however, is known. An abundance of short components have been developed and used commercially without staged clinical trials. Long-term survival is still unknown for many of these components. There remains tension between innovation and the moral duty to ensure that the introduction of new implants is controlled until safety and patient benefit are demonstrated. Implant innovation and subsequent use should be driven by proven clinical outcomes, rather than market and financial forces, and ethical practice must be ensured. Cite this article: Bone Joint J 2019;101-B:502–511. more...

A class of logarithmic-functors is constructed which allow additive invariants on categories to be formulated as functors on categories. Characters of such logarithmic representations provide a functorial structure for exotic torsions and include Chern characters, Reidemeister torsion and topological signatures. A number of examples are given. more...

We present an update in our earlier report on the Medial Rotation Total Knee Arthroplasty (TKA) when a cohort of 228 TKAs in 189 patients (78 M; 111 F) with a mean age of 67.9 years (28 - 90) was reported at a mean follow-up of six years (1 - 13). At that time, the ten-year survivorship for revision for any reason was 94.5% (95% confidence interval (CI): 85.1 - 100), but only 21 knees were at risk at that tenth year. The 10th annual report of the National Joint Registry (NJR) of England, Wales and Northern Ireland reported a deterioration in survivorship of the Medial Rotation TKA beyond the seventh year of follow-up. This implant previously had enjoyed the lowest rate of revision for any reported brand of prosthesis. As a result, we undertook a comprehensive audit of our original cohort at a mean follow-up of 8.5 years (0 - 19). With revision for aseptic loosening, and revision for any reason as the endpoints, with 125 prostheses at risk at ten years, the ten-year survivorship was 96.7% (95% CI: 93.3 - 100) and 92.3% (95% CI: 87.7 - 93.7) respectively. We have confirmed a decline in survivorship at ten years compared to our initial report. We believe that our results probably provide a more accurate picture of the longevity of the implant than figures available from the NJR, as they are based on detailed contemporary enquiries into each patient’s circumstances. Only ten knees in seven patients were lost to follow-up in our review. more...

Peri-prosthetic infection is amongst the most common causes of failure following total knee replacement (TKR). In the presence of established infection, thorough joint debridement and removal of all components is necessary following which new components may be implanted. This can be performed in one or two stages; two-stage revision with placement of an interim antibiotic-loaded spacer is regarded by many to be the standard procedure for eradication of peri-prosthetic joint infection.We present our experience of a consecutive series of 50 single-stage revision TKRs for established deep infection performed between 1979 and 2010. There were 33 women and 17 men with a mean age at revision of 66.8 years (42 to 84) and a mean follow-up of 10.5 years (2 to 24). The mean time between the primary TKR and the revision procedure was 2.05 years (1 to 8).Only one patient required a further revision for recurrent infection, representing a success rate of 98%. Nine patients required further revision for aseptic loosening, according to microbiological testing of biopsies taken at the subsequent surgery. Three other patients developed a further septic episode but none required another revision.These results suggest that a single-stage revision can produce comparable results to a two-stage revision. Single-stage revision offers a reduction in costs as well as less morbidity and inconvenience for patients.Cite this article: Bone Joint J 2014;96-B:759–64. more...

Published evidence has supported the use of femoral head resurfacing for patients with osteonecrosis of the femoral head.Between June 1999 and April 2001 we prospectively studied 15 femoral heads resurfaced in 12 patients with the Conserve Resurfacing Hemiarthroplasty. The male to female ratio was 8:4 and the mean age 38.7 years (range 26–60). The mean follow-up was 22.8 months (range 4–36). The senior author performed all procedures. There was one case of Ficat stage II, 9 cases of stage III and 5 cases of early stage IV. The mean time from onset of symptoms to surgery was 33.5 months (range 9–60). There were no intra or post-operative complications associated with any of the hemiarthroplasty procedures.ResultsNine of the fifteen patients had a poor result that warranted revision surgery within two years of prosthesis implantation. We conclude that in our hands the results of femoral resurfacing hemiarthroplasty are unpredictable and advise caution when recommending the procedure to patients with osteonecrosis of the femoral head. more...

Purpose: To analyse physiotherapy interventions and evaluate their effectiveness in the prevention and management of contracture with patients admitted in either vegetative or minimally conscious state in a UK Inpatient Regional Acquired Brain Injury Rehabilitation Service. Method: Retrospective audit of dependency levels and physiotherapy interventions in ten vegetative or minimally conscious state patients admitted over a 3-year period (2006–2009). Admission and discharge patient dependency status, Wessex Head Injury Matrix data and passive range of movement measurements on admission and discharge from physiotherapy were recorded. Results: All patients presented with hypertonicity including contractures and all initially received a manual stretching/passive movement programme. Casting/ splinting was employed in 8 cases and 7 received botulinum toxin injections. Standing regimes were initiated for 8 patients. No patient emerged out of either vegetative or minimally conscious state. Although they remained fully dependent for care needs, carer burden was reduced and all patients were able sustain a seating regimen. No minimal clinically important difference was observed in 85 out of 120 joint ranges measured (70.8%). Positive outcomes were observed in only 14 joints (11.7%) and negative outcomes in 21 joints (17.5%). Conclusion: At present, there is a paucity of evidence regarding physiotherapy efficacy to inform the management of patients in vegetative or minimally conscious state. Clearer agreed definitions of clinically important difference in passive range of movement are required to allow better interpretation of outcomes. Interventions should be aimed at minimising carer burden and developing individualised disability management programmes. Further research documenting the long-term outcomes in such patients is warranted. more...

Obstructive sleep apnoea, OSA, is formally defined as an apnoeahypopnoea index (AHI) of at least 5 episodes/hour (mild). Obesity, alcohol, smoking and sedatives may contribute to the development of OSA, as well as tonsilar hypertrophy and maxillary and/or mandibular retrognathia. Endocrine conditions such as hypothyroidism and acromegaly have also been reported associated with OSA. Except for excessive daytime sleepiness, headaches and irritability, OSA may lead to hypertension, heart failure, MI and stroke. Management involves reduction of predisposing factors such as obesity and alcohol. Treatment with continuous positive airway pressure (CPAP) is currently most common and best documented. Also uvulopalatopharyngeal surgery and so called phase II surgery, which means advancement of the jaw(s) with orthognatic surgical methods are used. Treatment with dental appliances is getting increasingly popular but the long term outcome remains debatable. more...

We report the long-term results of revision total hip replacement using femoral impaction allografting with both uncemented and cemented Freeman femoral components. A standard design of component was used in both groups, with additional proximal hydroxyapatite coating in the uncemented group. A total of 33 hips in 30 patients received an uncemented component and 31 hips in 30 patients a cemented component. The mean follow-up was 9.8 years (2 to 17) in the uncemented group and 6.2 years (1 to 11) in the cemented group. Revision procedures (for all causes) were required in four patients (four hips) in the uncemented group and in five patients (five hips) in the cemented group. Harris hip scores improved significantly in both groups and were maintained independently of the extent of any migration of the femoral component within the graft or graft–cement mantle. more...

Large tibial bone defects may cause problems at the time of revision total knee replacement. We report on 15 patients (15 knees) followed at a mean of 5.4 years (33-115 months) who underwent revision total knee replacement for severe tibial bone loss using shaped femoral head allograft and Freeman-Samuelson revision components (Zimmer, Winterthur, Switzerland). The mean American Knee Society Score pre-operatively was 22.7 points (0-45) increasing to a mean of 77.2 points (15-95) after operation. The survivorship for the series at 6 years was seven out of nine knees. One patient required an above knee amputation at 3.5 years, whilst another underwent a second revision TKR procedure at 3.4 years. Thirteen knees did not require further surgery and showed a mean time for allograft incorporation of 1.9 years (12-36 months) with no component migration. Severe tibial bone loss at the time of revision TKR surgery is a difficult problem to treat. Our case series demonstrates that when shaped femoral heads are used as structural allograft along with long stemmed components a successful result can be achieved. more...

ObjectivesThroughout the 20th Century, it has been postulated that the knee moves on the basis of a four-bar link mechanism composed of the cruciate ligaments, the femur and the tibia. As a consequence, the femur has been thought to roll back with flexion, and total knee arthroplasty (TKA) prostheses have been designed on this basis. Recent work, however, has proposed that at a position of between 0° and 120° the medial femoral condyle does not move anteroposteriorly whereas the lateral femoral condyle tends, but is not obliged, to roll back – a combination of movements which equates to tibial internal/ femoral external rotation with flexion. The aim of this paper was to assess if the articular geometry of the GMK Sphere TKA could recreate the natural knee movements in situ/in vivo.MethodsThe pattern of knee movement was studied in 15 patients (six male: nine female; one male with bilateral TKAs) with 16 GMK Sphere implants, at a mean age of 66 years (53 to 76) with a mean BMI of 30 kg/m2(20 to 35). The motions of all 16 knees were observed using pulsed fluoroscopy during a number of weight-bearing and non-weight-bearing static and dynamic activities.ResultsDuring maximally flexed kneeling and lunging activities, the mean tibial internal rotation was 8° (standard deviation (sd) 6). At a mean 112° flexion (sd 16) during lunging, the medial and lateral condyles were a mean of 2 mm (sd 3) and 8 mm (sd 4) posterior to a transverse line passing through the centre of the medial tibial concavity. With a mean flexion of 117° (sd 14) during kneeling, the medial and lateral condyles were a mean of 1 mm (sd 4) anterior and 6 mm (sd 4) posterior to the same line. During dynamic stair and pivoting activities, there was a mean anteroposterior translation of 0 mm to 2 mm of the medial femoral condyle. Backward lateral condylar translation occurred and was linearly related to tibial rotation.ConclusionThe GMK Sphere TKA in our study group shows movements similar in pattern, although reduced in magnitude, to those in recent reports relating to normal knees during several activities. Specifically, little or no translation of the medial femoral condyle was observed during flexion, but there was posterior roll-back of the lateral femoral condyle, equating to tibiofemoral rotation. We conclude that the GMK Sphere is anteroposteriorly stable medially and permits rotation about the medial compartment. Cite this article: Professor G. Scott. Can a total knee arthroplasty be both rotationally unconstrained and anteroposteriorly stabilised?: A pulsed fluoroscopic investigation. Bone Joint Res 2016;5:80–86. DOI: 10.1302/2046-3758.53.2000621. more...

Background and objectives Cognitive models suggest that attentional biases are integral in the maintenance of obsessive-compulsive symptoms (OCS). Such biases have been established experimentally in anxiety disorders; however, the evidence is unclear in Obsessive Compulsive disorder (OCD). In the present study, an eye-tracking methodology was employed to explore attentional biases in relation to OCS. Methods A convenience sample of 85 community volunteers was assessed on OCS using the Yale-Brown Obsessive Compulsive Scale-self report. Participants completed an eye-tracking paradigm where they were exposed to OCD, Aversive and Neutral visual stimuli. Indices of attentional bias were derived from the eye-tracking data. Results Simple linear regressions were performed with OCS severity as the predictor and eye-tracking measures of the different attentional biases for each of the three stimuli types were the criterion variables. Findings revealed that OCS severity moderately predicted greater frequency and duration of fixations on OCD stimuli, which reflect the maintenance attentional bias. No significant results were found in support of other biases. Limitations Interpretations based on a non-clinical sample limit the generalisability of the conclusions, although use of such samples in OCD research has been found to be comparable to clinical populations. Future research would include both clinical and sub-clinical participants. Conclusions Results provide some support for the theory of maintained attention in OCD attentional biases, as opposed to vigilance theory. Individuals with greater OCS do not orient to OCD stimuli any faster than individuals with lower OCS, but once a threat is identified, these individuals allocate more attention to OCS-relevant stimuli.. more...

The Head of Department is caught between department members and senior management which underscores courage and resilience as a middle leader. In many ways, the Head of Department epitomizes the idea that middle leaders are “the meat in the sandwich” (Anderson, Scott, Coates, 2008, p. 12). This study examines the challenges associated with the leadership of an English Department within a regional, non-government school in NSW, Australia. Using the approach of an Institutional Ethnography incorporating a Teacher Self–Study, my role as Head of Department is examined. As Head of Department, I was able to implement a number of actions taken in order to assist with the improvement of the teaching and learning in the Department. These practices include: the development of a Department Handbook; incorporating Faculty Meetings with a focus upon pedagogy and shared practice; developing a collegial culture in the English Department which involved sharing of resources between teachers, classroom visits between teachers and also one-on-one conversations; addressing the underperformance of staff; writing and resourcing teaching and learning programmes; building staff morale; and, protecting the English teachers from hindrances to their teaching. It is this qualitative aspect involved in transforming an English Department and the actions taken to improve it that is the focus of this study. Courage Under Fire: Navigating the Head of Department Role in Challenging Circumstances as the title of this thesis indicates, serves to encapsulate my story within this study. The research design incorporated a variation upon the participant observer approach in the form of a Teacher Self-Study firmly situated within a framework of an Institutional Ethnography. A variety of data sources were drawn upon including semi-structured interviews, a survey, Department Review, Registration and Accreditation Documentation, Researcher Journal, and a Professional Review. The key findings of this study relate to being courageous in managing the performance of staff within the department and being resilient to cope with the loneliness that this created for me in this role. This study also highlighted resilience and courage needed to maintain an effective working relationship with the Senior Management Team. This study found that there were many time pressures on my life as HoD. Teaching and learning responsibilities, pastoral care and co-curricular involvement as well as other duties of the HoD made the role demanding. At the heart of HoD leadership are the interactions with teachers and students on a daily basis. The importance of effective interpersonal skills in the development of a collegial culture within the Department is an important finding in this study. However, as learning is the core business of the school, the HoD needs to be someone of outstanding curriculum and pedagogical expertise. This study shows how a middle leader with strong leadership vision and skills can positively impact a department despite a somewhat negative Senior Management Team operating from above in the school hierarchical approach. more...

The aim of this study was to assess whether a femoral component which retained the neck reduced the incidence of leg-length inequality following total hip arthroplasty. A retrospective review was undertaken of 130 consecutive primary total hip arthroplasties performed between April 1996 and April 2004 using such an implant. There were 102 suitable patients for the study. Standardised pre- and post-operative pelvic radiographs were measured by an independent investigator to the nearest millimetre. The leg-length inequality was reduced from a mean pre-operative value of −0.71 cm to a mean of 0.11 cm post-operatively. Of the 102 patients 24 (23.5%) had an equal leg-length post-operatively, and 95 (93.1%) had a leg-length inequality between −1 cm and 1 cm. more...

The Rotalok screw-in threaded acetabular component was prospectively reviewed with 10-year clinical and radiological follow-up for 60 patients. Nine patients died and 5 were lost to follow-up. Clinically, 28 patients were pain-free, 13 had mild pain, and 3 had moderate pain. Thirteen patients underwent revision for loosening and 3 required revision but were unfit. Superior migration, angular migration, and zone lucency were measured radiologically. Cumulative survival was 70.75% with revision surgery as the end point and 60% with combined clinical failure and revision as the end point. Angular migration of 3° or more was a significant predictor of clinical failure and revision (P < .0001), with 5° being very highly predictive with a sensitivity of 0.72 and a specificity of 1.00. Revision was associated with younger patients (P = .03) and autograft use without screw stabilization (P = .024). The high failure rate of the Rotalok necessitates careful clinical and radiological follow-up, with asymptomatic radiological angular migration often the first predictor of failure. more...

WOS: 000243882500001 PubMed: 19219800 We studied, to ten years, migration by vertical displacement and angular change using a digitizer and standard radiographs and survival of three methods of acetabular fixation in primary hip replacement. Two implants were uncemented metal-backed components, one version of which was hydroxyapatite-coated. Both types had 28 mm polyethylene inserts. The third type was a cemented all-polyethylene cup with a 28 mm internal diameter All cups articulated with a Freeman neck-retaining stem. The purpose was to see if the early migration data predicted the long-term outcome and could be used to forecast implants that would fail for the purpose of pre-market assessment. No statistical differences were found between the groups in the parameters studied. At the threshold accuracies of our migration measurements (three millimetres and three degrees) at three years, we could not identify components that would subsequently fail. However, migration less than these threshold values and the absence of radiolucent lines were strongly associated with implant survival at ten years. Our system was insufficiently accurate for pre-market surveillance. more...

Until recently, the options for patients with a degenerative hip and a previous femoral osteotomy included arthrodesis, total hip arthroplasty with osteotomy or CADCAM total hip arthroplasty. Technological improvements have allowed the reintroduction of hip resurfacing. We report the results of hip resurfacing in four patients with previous valgus or extension proximal femoral osteotomies. Patients were assessed for pre and post-operative pain, walking distance and range of movement. All patients had an abnormal angulation, of the femoral neck, of 30 degrees or more in either coronal or sagittal plane. They are within the severe group of disordered proximal femoral anatomy according to Harris et al. The mean age at operation was 32 years (range 30 - 34). The mean follow-up was 3 years (range 1 - 8). Postoperatively no patient required analgesia and all patients had a minimum uninterrupted walking ability of 30 or more minutes with the exception of the patient who had undergone previous leg lengthening. We recommend this comparatively straightforward operation compared to current alternatives. (Hip International 2005; 15: 119-22). more...

Thirty-six consecutive total knee arthroplasties with hydroxyapatite (HA)-coated femoral components were prospectively followed up according to a standardised protocol for a mean period of 10 years (range, 7-11 years). Clinical and radiologic examination was performed at each follow-up evaluation. One patient (1 knee) was lost to follow up at 7 years, and 4 other patients (6 knees) died. Radiographs were studied for signs of loosening and presence of lucencies. Survival analysis was performed using a life table with revision as the criterion for failure. Two knees (1 patient) were revised because of aseptic loosening. The tibial component of one other knee was revised because of osteolysis in the medial tibial condyle. In the remaining knees, no radiologic evidence of loosening was seen. The survival of the femoral component at a mean follow-up time of 7 years, when 31.5 knees were at risk, was 94% with revision for femoral aseptic loosening as the end point. At 10 years, when 24 knees were at risk, the survival remained 94%. more...

A technique for revision total knee arthroplasty managing posterior femoral condylar bone loss with prepolymerized polymethyl methacrylate cement spacers as augments to the femoral component is described in 10 consecutive cases. The maximum follow-up time is 63 months. This method allows for maintenance of the posterior joint line, which in turn facilitates appropriate flexion-extension gap balancing. The cement spacers are inexpensive compared with metal augments. An experimental study confirms that the cement spacers produce a chemical and physical bond with fresh cement. This eliminates the risk of particulate debris production between the cement augment and the fixation cement. Although the cement spacers have been produced to match one manufacturer’s implants, they could be applied to other knee systems. more...

We have reviewed 29 patients (30 hips) who had undergone revision total hip arthroplasty using a Freeman metal-backed acetabular component and acetabular impaction allografting. The mean follow-up was for 15.3 years (12 to 17). Five patients (5 hips) died with the prosthesis in situ and four (4 hips) were lost to follow-up. Twelve hips had failed and in the remaining nine there were minor symptoms. The mean time to failure requiring further surgery was nine years. Excluding patients who were lost to follow-up or had died, 72% of the hips were radiologically loose at the last review. The commonest pattern in those requiring revision was failure of the reinforcement ring in adduction with remodelling of the medial wall. Of the nine patients who had not undergone revision, one with bilateral replacements had no current radiographs and only three of the remaining seven replacements had no radiological signs of loosening. The short-term results for this technique have been reported to be satisfactory, but in the long term they are not. The factors associated with failure include the design of the prosthesis, which has been implicated in disappointing long-term results when used in primary arthroplasty, but not with the frequency of failure found in this series. It seems that the reliance on peripheral screw fixation over a bed of allograft without bridging the graft does not provide sufficient stability to allow incorporation of the graft. more...

A survival analysis and radiological review were performed on a series of femoral total knee arthroplasty (TKA) prostheses either cemented (150 cases) or cementless, press-fit (201 cases). The internal surface of the femoral components were shot-blast CoCr alloy. The incidence of loosening of the femoral component at 6 years was 9.8% with cementless fixation and 0.6% with cement (P more...

Necrotising fasciitis is a rapidly progressive, polymicrobial synergistic soft tissue infection that spreads along fascial planes beneath seemingly normal skin. The relatively benign appearance of the extremity is misleading and often results in delay in diagnosis and increased morbidity or death. Involvement of bone is not a recognised feature. Successful management requires early detection, radical surgical debridement and broad spectrum intravenous antibiotics. We report an unusual case of necrotising fasciitis in a 61-year-old male who presented with musculoskeletal symptoms and gas within the femoral head as well as surrounding soft tissues. This resulted in necrosis of the femoral head with the development of chronic osteomyelitis, requiring long-term antibiotics and ultimately proximal femoral excision. We describe a previously unreported presentation of this condition with musculoskeletal involvement and discuss the potential pitfalls in delayed diagnosis. more...

Our aim was to analyse the influence of the size, shape and number of particles on the pathogenesis of osteolysis. We obtained peri-implant tissues from 18 patients having revision surgery for aseptically loosened Freeman total knee replacements (10), Charnley total hip replacements (3) and Imperial College/London Hospital double-cup surface hip replacements (5). The size and shape of the polyethylene particles were characterised using SEM and their concentration was calculated. The results were analysed with reference to the presence of radiological osteolysis. The concentration of polyethylene particles in 6 areas with osteolysis was significantly higher than that in 12 areas without osteolysis. There were no significant differences between the size and shape of the particles in these two groups. We conclude that the most critical factor in the pathogenesis of osteolysis is the concentration of polyethylene particles accumulated in the tissue. more...

The aim of this study was to evaluate the relative contribution of polyethylene, metal, and polymethylmethacrylate (cement) particles to the overall bone loss in aseptic loosening. Twenty-four interface tissues with adjacent bone were obtained during 17 revision total joint arthroplasties (11 hips and six knees). Osteoclasts and macrophages were identified immunohistochemically on the bone surface. The length of the bone surface in contact with these cell types was measured and analyzed with reference to the particulate species present within the fibrous interface. The presence of abundant polyethylene particles significantly increased the proportion of the bone surface in contact with macrophages but did not have a significant influence on that of osteoclasts. Osteoclastic bone resorption was significantly more extensive in the presence of metal particles. In contrast, the presence of cement particles did not have a significant influence on macrophage or osteoclast coverage of the bone surface. These results highlight the significance of polyethylene particles in macrophage recruitment and subsequent osteolysis and suggest a different mechanism of bone loss related to metal, namely mediation through osteoclastic activities. The relative contribution of cement particles was negligible and needs reevaluation in light of evidence provided by others. more...

To obtain information about the bone scintigraphic appearance of a hydroxyapatite (HA)-coated proximal femoral implant, this examination was performed on 24 patients with a clinically and radiologically successful femoral implant in hip arthroplasty. The prosthesis had a proximal HA coating for supplementary fixation. The patients' mean age was 50.3 years (range, 28–65 years) at operation. The interval from the operation to the scintigraphy ranged from 6 months to 5.5 years (mean, 2.2 years). Scintigraphy was performed using 99m Tc-medronic acid. Quantitative counts were recorded in 4 zones: 3 along the length of the implant (trochanteric region with HA coating, midprosthesis, and distal tip) and 1 below the prosthesis. The results were expressed as ratios using the nonoperated femur as a control value. The results demonstrated that the mean activities in all 4 zones were increased relative to the untreated side. The highest activity was observed in the region around the prosthetic tip, with an elevation of 46% above the control value. This activity showed a significant decline over time. The counts recorded in the trochanteric region, where the implant was coated with HA, were 20% above the control value and similar to those seen in its adjacent noncoated midprosthetic region. In the trochanteric region, however, the activity did not show a decline over the follow-up period. more...

We compared the radiological appearances and survival of four methods of fixation of a femoral stem in 538 hips after follow-up for five or ten years. The fixation groups were: 1) press-fit shot-blasted smooth Ti-Al-V stem; 2) press-fit shot-blasted proximally ridged stem; 3) proximal hydroxyapatite (HA) coating; and 4) cementing. Survival analysis at five to ten years showed better results in the HA-coated (100% at five to six years) and cemented stems (100% at 5 to 6 years) than in the two press-fit groups. There was a higher mean rate of migration in the smooth and ridged Ti-Al-V shot-blasted press-fit groups (0.8 mm/year and 0.6 mm/year, respectively) when compared with the HA-coated and cemented prostheses (both 0.3 mm/year). More radiolucent lines and osteolytic lesions were seen in the press-fit groups than in either the HA-coated or cemented implants, with a trend for a lower incidence of both in the HA compared with the cemented group. Proximal osteopenia increased in the press-fit and cemented prostheses with time, but did not do so in the HA group. There was a higher incidence of resorption of the femoral neck with time in the cemented group than in the other three. We conclude that the HA and the cemented interfaces both provide secure fixation with a trend in favour of HA. The cemented prosthesis meets the suggested National Institutes of Health definition of ‘efficacious’ at ten years. more...

Osteolysis induced by wear particles has been recognized as one of the major causes of long-term failure in total joint replacements. However, little is currently known about the exact nature of particles, as the particles are too small to be characterized by light microscopy. In this study, ultra-high molecular weight polyethylene (UHMWPE) particles retrieved from ten cases (six cemented and four uncemented) for Freeman type conforming tibiofemoral total knee replacements (TKRs), three Charnley total hip replacements (THRs) and five Imperial College/London Hospital double cup surface hip replacements for aseptic loosening were extracted using a high-performance method with ultracentrifugation and characterized by scanning electron microscopy. The equivalent circle diameter (ECD) of all 18 cases ranged from 0.40 to 1.15 μm (Mean ± SE = 0.70 ± 0.05 μm, median = 0.67 μm). The aspect ratio was 1.50 to 2.04 (Mean ± SE = 1.75 ± 0.04, median = 1.73), and roundness was 1.24 to 2.34 (Mean ± SE = 1.61 ± 0.07, median = 1.65). The numbers of particles were 5.2 × 108 to 9.17 × 1010/g tissue (Mean ± SE = 1.42 × 1010 ± 5.41 × 109/g tissue, median = 7.04 × 109). The number of polyethylene (PE) particles/g tissue in TKRs was significantly larger than that in THRs (1.04 × 1010/g tissue and 2.16 × 109/g tissue respectively, median. p = 0.03, Mann-Whitney U test). Unstable fixation of the tibial PE component might account for the accumulation of a large number of PE particles in the interface tissue. more...

We report the radiological and clinical outcome of a press-fit (SLF) acetabular component at two to three years in two groups of patients having primary total hip replacement. In 69 the implant was coated with hydroxyapatite (HA) and in 40 it was uncoated. The stability of the cup was assessed by measurement of proximal migration and change in the angle of inclination. The clinical results in the two groups did not differ significantly, and the mean proximal linear wear was similar in both. Fewer radiolucent lines (RLLs) were seen on the radiographs of cups coated with HA. The mean proximal migration was studied by calculating regression lines for each patient using migration measurements: for the SLF+HA group the mean slope was 0.06 mm/year and for the SLF–HA group 0.20 mm/year (p = 0.22). The change in the angle of inclination during follow-up was also consistently smaller in HA–coated cups. Using regression methods the SLF+HA group had a mean slope of 0.08°/year and the SLF-HA group 0.44°/year (p = 0.023). Partial HA coating appeared to have no effect on the clinical outcome or on the rate of wear of polyethylene, but there was a trend towards a reduced rate of proximal migration, and a significant reduction in rotational migration and the number of radiolucent lines. This suggests that HA coating enhances the stability of this acetabular component. more...

We measured the posterior tibial slope for the medial and lateral tibial plateau separately in MR images of 143 knees (71 women, 72 men) and compared the measurements between genders and different ethnic groups. For the whole population the mean medial slope was 5.7 degrees and the mean lateral slope 5.6 degrees. There was a significant difference between the medial and lateral posterior tibial slope in the Asian patients compared with other ethnic groups (p0.001). We have shown that measurement of the posterior tibial slope (PTS) could be reliably performed on MR images, revealing a gender difference. These findings might have clinical relevance when performing reconstructive surgery at the knee in determining ideal placement of the tibial component. more...

The outcome at ten years of 100 Freeman hip stems (Finsbury Orthopaedics, Leatherhead, United Kingdom) retaining the neck with a proximal hydroxyapatite coating in a series of 52 men (six bilateral) and 40 women (two bilateral), has been described previously. None required revision for aseptic loosening. We have extended the follow-up to 20 years with a minimum of 17 years. The mean age of the patients at total hip replacement was 58.9 years (19 to 84). Six patients were lost to follow-up, but were included up to their last clinical review. A total of 22 patients (22 hips) had died, all from causes unrelated to their surgery. There have been 43 re-operations for failure of the acetabular component. However, in 38 of these the stem was not revised since it remained stable and there was no associated osteolysis. Two of the revisions were for damage to the trunnion after fracture of a modular ceramic head, and in another two, removal of the femoral component was because of the preference of the surgeon. In all cases the femoral component was well fixed, but could be extracted at the time of acetabular revision. In one case both components were revised for deep infection. There has been one case of aseptic loosening of the stem which occurred at 14 years. This stem had migrated distally by 7.6 mm in ten years and 8.4 mm at the time of revision at which stage it was found to be rotationally loose. With hindsight this component had been undersized at implantation. The survivorship for the stem at 17 years with aseptic loosening as the endpoint was 98.6% (95% confidence interval 95.9 to 100) when 62 hips were at risk. All remaining stems had a satisfactory clinical and radiological outcome. The Freeman proximally hydroxyapatite-coated femoral component is therefore a dependable implant and its continued use can be recommended. more...

We describe the survivorship of the Medial Rotation total knee replacement (TKR) at ten years in 228 cemented primary replacements implanted between October 1994 and October 2006, with their clinical and radiological outcome. This implant has a highly congruent medial compartment, with the femoral component represented by a portion of a sphere which articulates with a matched concave surface on the medial side of the tibial insert. There were 78 men (17 bilateral TKRs) and 111 women (22 bilateral TKRs) with a mean age of 67.9 years (28 to 90). All the patients were assessed clinically and radiologically using the American Knee Society scoring systems. The mean follow-up was for six years (1 to 13) with only two patients lost to follow-up and 34 dying during the period of study, one of whom had required revision for infection. There were 11 revisions performed in total, three for aseptic loosening, six for infection, one for a periprosthetic fracture and one for a painful but well-fixed replacement performed at another centre. With revision for any cause as the endpoint, the survival at ten years was 94.5% (95% CI 85.1 to 100), and with aseptic loosening as the endpoint 98.4% (95% CI 93 to 100). The mean American Knee Society score improved from 47.6 (0 to 88) to 72.2 (26 to 100) and for function from 45.1 (0 to 100) to 93.1 (45 to 100). Radiological review failed to detect migration in any of the surviving knees. The clinical and radiological results of the Medial Rotation TKR are satisfactory at ten years. The increased congruence of the medial compartment has not led to an increased rate of loosening and continued use can be supported. more...

Background: Clinical observations suggest that metal-on-metal arthroplasties that have been implanted for more than twenty years do fail. It is proposed that there are not two, but three distinct phases of wear life for any metal-on-metal implant system: bedding-in, steady state, and end point. In this study, we asked two questions: can we explain late failure due to wear, and will there be a late failure mechanism due to a change in the frictional torque? Methods: In order to characterize wear failure, an analysis was made of five retrieved metal-on-metal couples that were mapped with use of a roundness machine. A geometrical model was developed on the basis of these observations, and wear at the end point was calculated. The literature on first-generation metal-on-metal implants retrieved for aseptic loosening was reviewed to assess the agreement with the retrieval findings as well as the wear model. Results: A wear patch of an appreciable and constant size could be measured in all five retrieved couples. The end point of revision was observed to occur when the wear progression reached a contact area corresponding to approximately 75% of the projected diameter of the ball. The wear volume was calculated from the geometry. The available literature describing the wear characteristics of retrieved bearings after successful clinical use showed good agreement with the calculated wear model. Conclusions: During the implant life of long-term successful metal-on-metal devices, a wear patch develops, as evident from retrieved failed devices. Failure often occurs through loosening, and the observed wear patch is similar in size for devices measured by us and for those described in the literature. We hypothesized that failure by loosening occurs through the accumulation of wear, which eventually leads to high friction within the bearing and increased torsional forces across the joint and its fixation. Clinical Relevance: This study will lead to a better understanding of long-term failure of first-generation metal-on-metal devices, which may lead to improvements in design and increased survival for more modern devices. more...

We investigated the changes in surface roughness of retrieved femoral components in 18 men and four women at revision knee surgery. The mean age at revision was 68.4 years and the mean period of implantation was for 55.6 months. Eighteen implants were retrieved for aseptic loosening and four for infection. The surface changes in the articulating areas were inspected visually and the roughness (Ra) analysed with a profilometer. Parallel scratching and burnishing were the two main forms of damage. The mean Ra measurements in the articulating areas showed no statistically significant difference when compared with those in a control area on either side of the patellar groove at the apex of the femoral flange. This suggests that it is not essential to revise a well-fixed and correctly aligned femoral component where the polished surface has become burnished or bears fine parallel scratches, if the revision is conducted solely for failure of the tibial component. more...

Hypothesis : The fall in haemoglobin following unilateral total knee arthroplasty is reduced by tranexamic acid administration. Methods : 60 patients were studied in total, 30 received tranexamic acid 10 mg/kg on induction and a further dose shortly before the release of the tourniquet. Surgery was performed by the senior author in a standardised fashion using the Freeman Samuelson cemented total knee replacement. Haemoglobin levels were measured 2 weeks pre and 3 days post operatively. Any complications were noted. A control group was matched using the Bone and Joint Research Unit database for age, sex, disease and pre-operative haemoglobin level. This group had been monitored in the same way as the group treated with tranexamic acid. Results : In the group receiving no tranexamic acid the mean fall in haemoglobin was 2.8 g/dl (95% CI of mean 2.5–3.2) and in the group treated with tranexamic acid 1.7 g/dl (95% CI of mean 1.3–2) P Conclusions : The administration of tranexamic acid is an effective method of reducing the haemoglobin fall following knee arthroplasty. more...

We describe the survival at ten years of 100 femoral components of the Freeman hip prosthesis. It is proximally hydroxyapatite (HA)-coated and was fixed without cement. Radiological assessment identified radiolucent lines (RLLs) and lytic lesions and was used to measure migration. The criterion of failure was revision or impending revision for aseptic femoral loosening. No femoral components were revised or are awaiting revision for aseptic loosening, giving 100% survival at ten years (95% confidence interval, 95.7 to 100), although 59 were at risk at ten years. Two components were revised for fracture of a ceramic head with damage to the trunnion. Although well fixed in each, for survival analysis we evaluated the hip as if the patient had died. Twelve acetabular components were revised and at each operation the femoral component was found to be well fixed, was not disturbed and remained in the survival analysis. Three patients were lost to follow-up, and 12 died with well-functioning prostheses. Radiologically, all except one of the components appeared to be well fixed with no RLLs and no lytic lesions at the latest follow-up. The mean vertical migration was 0.4 mm at one year, 0.8 mm at two years and 1.4 mm at ten years. One component had migrated 7.6 mm at ten years (2.1 mm in year 1) and developed RLLs in Gruen zones I and II. The symptoms, however, were only minor and revision was not indicated. Our study has shown that proximal HA coating gives effective fixation for a femoral component. more...

We have compared the survival and radiological outcome at ten years after total hip replacement using two techniques for preparing the femoral canal. The same prosthesis was used throughout and all operations were performed by the same surgical team. In technique 1 the canal was over-reamed by 2 mm and in technique 2 it was reamed to the same size as the prosthesis. Technique 1 was performed on 92 patients and technique 2 on 97 patients. The survival at ten years was 97.2% (90.6 to 99.2) for technique 1 and 98.8% (92.9 to 99.8) for technique 2. Vertical migration was greater in technique 1 (1.8 mm versus 1.0 mm at five years; p = 0.36). There were significantly more lytic lesions and radiolucent lines at five years (p = 0.0061) with technique 1. We conclude that technique 2 is not worse and may produce better long- term results than current teaching suggests. more...

Today the “orthodox“ treatment for the infected TKR is a two-stage revision. As a consequence there are too few reports of the outcome of the quicker, potentially simpler single-stage revision procedure to permit a balanced view to be taken of its place. However, we believe that as at the hip, successful single-stage revision is certainly possible although technically demanding. Our results have been encouraging and we continue to use this procedure. The literature, such as it is, suggests that the results are no worse than those of a two-stage revision10,11,13,14 for what remains a challenging complication of TKR. more...

To the Editor: I read with concern the article by Kim et al. [1] on the comparison of short-term outcomes of the PFC rotating platform and the Medial Pivot total knee replacements. Osteoarthritis in the knee must differ considerably in its presentation in the Korean population from that encountered in western society where the need for bilateral total knee replacement at presentation remains the exception rather than the norm, and which may limit general applicability of the findings described by Kim et al. Also, the study population was manipulated as patients with rheumatoid arthritis were excluded; in my view, this subgroup would obtain less favorable results from rotating platforms. However, numerous errors make interpretation of the data difficult. The authors state they treated 98 patients (198 knees) with bilateral arthritis. Clearly one of these figures is wrong. The authors also state three patients were excluded because they had infection, but the number of patients continuing in the analysis was reduced only to 96. Also, four patients were lost to followup. If the starting number was 98 patients, with reported exclusions only 91 patients were studied, not 92 as stated. Additional errors occurred in the presentation of the results. The mean preoperative ranges of movement for the two designs were 124° each as displayed in Table 2, but 124° vs 123° in the text. In Table 3, 38 of 92 is 41%, not 63% as written, and 51 of 92 is 55%, not 34% as written. Table 6 has curiously identified equal numbers of patients who received PFC knees, 37 (40%) in each of the available satisfaction ratings giving a total of 148 knees. Given the limited period between February and April 2004 in which all these operations were performed, it would be helpful to receive confirmation that Dr. Kim did perform all the operations as reported. As the exclusion criteria for the study was infection, additional explanation is required why 12 infected knees (11 Medial Pivot, one PFC) remain in the analysis of the results particularly as dissatisfaction in one group seems to hinge on the patients’ experience of infection. As the implants and instruments were not implicated as the source of the infections, it suggests that inexperience with the instrumentation might be relevant. I wonder if Kim et al. could describe their experience using the Medial Pivot replacement before commencing the trial. Furthermore, it would be relevant to know if this problem occurred more frequently in the second side than the first. Additionally, the antibiotic prophylaxis observed in these circumstances is highly relevant. Although the surgical technique was said to be common for all patients, three separate ways of setting the rotation of the femoral jig were used. The knees were said to be subject to a balancing procedure before implantation of the components. However, in the case of the rotating platforms, “Additional time was spent doing more meticulous ligament balance [1] [sic]”. One wonders whether meticulous ligament balancing was not performed for the Medial Pivot knee and why such a meticulous endeavor was not afforded to all total knee replacements. This suggests the surgical technique was quite different between the designs. The use of two scoring systems to examine outcome is commonplace, but the Hospital for Special Surgery score was superseded by the AKSS to distinguish function that may depend on extraneous factors from the outcome for the knee. I believe it is pointless to use both scores in the same study because of the overlap in the questions and thresholds. In the radiographic analysis I wonder if the authors are confident no bias was present as the implants are radiographically different. The kappa score for intraobserver error did not reach the high level one would have anticipated, and I note in the Discussion that the authors acknowledge they did not study interobserver error. Statistical analysis was performed with analysis of variance but it is unlikely the scores were distributed normally; generally they are skewed. I should have thought that Wilcoxon’s matched pairs signed rank test would have been more appropriate at a stated level of significance of p more...

To elucidate the reactions of bone around aseptically loosened total joint arthroplasties, 24 interface tissues with adjacent bone were obtained in 17 revision operations (11 hips and six knees). The morphology of the bone surface next to the interface membrane was investigated with histochemical and immunohistochemical techniques and then histomorphometrically analysed. One-third of the total bone surface. 32.69 +/- 5.16% (mean +/- SE) (n = 24), showed positive alkaline phosphatase activity. The bone surface in contact with the cells positive for CD11b (a macrophage marker) amounted to 19.33 +/- 5.16% (n = 24). The proportion of the osteoclastic bone resorption estimated by vitronectin receptor expression was 7.67 +/- 1.82% (n = 21). Tissues retrieved from the sites where radiographic evidence of osteolysis was present (n = 12) had a significantly larger extent of the bone surface in contact with CD11b-positive cells than did the tissues from areas without osteolysis (n = 12, p = 0.0067, Mann-Whitney U test), whereas no significant difference was observed in the extent of osteoclastic bone resorption. These data demonstrate that active bone formation, regarded as a repair process, is the most common feature even in revised cases. They also highlight the role played by macrophages, not as cells producing inflammatory mediators that could activate osteoclasts, but as cells primarily responsible for the bone loss in osteolytic lesions. more...

Twenty-three patients who had an established non-union of a long bone were entered into a prospective, double-blind trial in which electrical capacitive coupling was used for treatment. Twenty-one patients completed the study: ten who were actively managed and eleven who were managed with a placebo unit. The non-union healed in six of the ten patients who had been managed actively but in none of the patients who had been managed with the placebo unit. This difference in the rates of healing between the actively managed and the placebo groups is highly significant (p = 0.004). more...

Which simple roentgenographic angle should be used to assess medial (varus) deviation of the first metatarsal in cases of hallux valgus has been a topic of debate. Measurements were made from roentgenograms of 100 symptomatic feet in women with hallux valgus. These were compared with similar measurements obtained from symptomatic normal feet of women of a similar age distribution. The hallux valgus angle was associated with medial deviation of the first metatarsal measured by all three of the parameters defined and tested, i.e., the intermetatarsal, metatarsus primus varus, and metatarsus omnis varus angles. Of these, the best measure was the intermetatarsal angle, which in the hallux valgus feet differed significantly from controls more than the other measurements. No evidence was found to support any concept of second metatarsal deviation from normal. more...