Aims. Natural Language Processing (NLP) offers an automated method to extract data from unstructured free text fields for arthroplasty registry participation. Our objective was to investigate how accurately NLP can be used to extract structured clinical data from unstructured clinical notes when compared with manual data extraction. Methods. A group of 1,000 randomly selected clinical and hospital notes from eight different surgeons were collected for patients undergoing primary arthroplasty between 2012 and 2018. In all, 19 preoperative, 17 operative, and two postoperative variables of interest were manually extracted from these notes. A NLP algorithm was created to automatically extract these variables from a training sample of these notes, and the algorithm was tested on a random test sample of notes. Performance of the NLP algorithm was measured in Statistical Analysis System (SAS) by calculating the accuracy of the variables collected, the ability of the algorithm to collect the correct information when it was indeed in the note (sensitivity), and the ability of the algorithm to not collect a certain data element when it was not in the note (specificity). Results. The NLP algorithm performed well at extracting variables from unstructured data in our random test dataset (accuracy = 96.3%, sensitivity = 95.2%, and specificity = 97.4%). It performed better at extracting data that were in a structured, templated format such as range of movement (ROM) (accuracy = 98%) and implant brand (accuracy = 98%) than data that were entered with variation depending on the author of the note such as the presence of deep-vein thrombosis (DVT) (accuracy = 90%). Conclusion. The NLP algorithm used in this study was able to identify a subset of variables from randomly selected unstructured notes in arthroplasty with an accuracy above 90%. For some variables, such as objective exam data, the accuracy was very high. Our findings suggest that automated algorithms using NLP can help orthopaedic practices retrospectively collect information for registries and quality improvement (QI) efforts. Cite this article: Bone Joint J 2020;102-B(7 Supple B):99–104

Aims. Increasingly, patients with bilateral hip arthritis wish to undergo staged total hip arthroplasty (THA). With the rise in demand for arthroplasty, perioperative risk assessment and counselling is crucial for shared decision making. However, it is unknown if complications that occur after a unilateral hip arthroplasty predict complications following surgery of the contralateral hip. Patients and Methods. We used nationwide linked discharge data from the Healthcare Cost and Utilization Project between 2005 and 2014 to analyze the incidence and recurrence of complications following the first- and second-stage operations in staged bilateral total hip arthroplasty (BTHAs). Complications included perioperative medical adverse events within 30 to 60 days, and infection and mechanical complications within one year. Conditional probabilities and odds ratios (ORs) were calculated to determine whether experiencing a complication after the first stage of surgery increased the risk of developing the same complication after the second stage. Results. A total of 13 829 patients (5790 men and 8039 women) who underwent staged BTHAs were analyzed. The mean age at first operation was 62.9 years (14 to 95). For eight of the 12 outcomes evaluated, patients who experienced the outcome following the first arthroplasty had a significantly increased probability and odds of developing that same complication following the second arthroplasty, compared with those who did not experience the complication after the first surgery. This was true for digestive complications (OR 25.67, 95% confidence interval (CI) 13.86 to 46.08; p < 0.001), urinary complications (OR 6.48, 95% CI 1.7 to 20.73; p = 0.01), haematoma (OR 12.17, 95% CI 4.55 to 31.14; p < 0.001), deep vein thrombosis (OR 4.82, 95% CI 2.34 to 9.65; p < 0.001), pulmonary embolism (OR 12.03, 95% CI 2.02 to 46.77; p = 0.01), deep hip infection (OR 534.21, 95% CI 314.96 to 909.25; p < 0.001), superficial hip infection (OR 1574.99, 95% CI 269.83 to 9291.81; p < 0.001), and mechanical malfunction (OR 117.49, 95% CI 91.55 to 150.34; p < 0.001). Conclusion. The occurrence of certain complications after unilateral THA is associated with an increased risk of the same complication occurring after staged arthroplasty of the contralateral hip. Patients who experience these complications after unilateral hip arthroplasty should be appropriately counselled regarding their risk profile prior to undergoing staged contralateral hip arthroplasty. Cite this article: Bone Joint J 2019;101-B(6 Supple B):77–83

Aims. The aim of this study was to estimate time to arthroplasty among patients with hip and knee osteoarthritis (OA), and to identify factors at enrolment to first-line intervention that are prognostic for progression to surgery. Methods. In this longitudinal register-based observational study, we identified 72,069 patients with hip and knee OA in the Better Management of Patients with Osteoarthritis Register (BOA), who were referred for first-line OA intervention, between May 2008 and December 2016. Patients were followed until the first primary arthroplasty surgery before 31 December 2016, stratified into a hip and a knee OA cohort. Data were analyzed with Kaplan-Meier and multivariable-adjusted Cox regression. Results. At five years, Kaplan-Meier estimates showed that 46% (95% confidence interval (CI) 44.6 to 46.9) of those with hip OA, and 20% (95% CI 19.7 to 21.0) of those with knee OA, had progressed to arthroplasty. The strongest prognostic factors were desire for surgery (hazard ratio (HR) hip 3.12 (95% CI 2.95 to 3.31), HR knee 2.72 (95% CI 2.55 to 2.90)), walking difficulties (HR hip 2.20 (95% CI 1.97 to 2.46), HR knee 1.95 (95% CI 1.73 to 2.20)), and frequent pain (HR hip 1.56 (95% CI 1.40 to 1.73), HR knee 1.77 (95% CI 1.58 to 2.00)). In hip OA, the probability of progression to surgery was lower among those with comorbidities (e.g. ≥ four conditions; HR 0.64 (95% CI 0.59 to 0.69)), with no detectable effects in the knee OA cohort. Instead, being overweight or obese increased the probability of OA progress in the knee cohort (HR 1.25 (95% CI 1.15 to 1.37)), but not among those with hip OA. Conclusion. Patients with hip OA progressed faster and to a greater extent to arthroplasty than patients with knee OA. Progression was strongly influenced by patients’ desire for surgery and by factors related to severity of OA symptoms, but factors not directly related to OA symptoms are also of importance. However, a large proportion of patients with OA do not seem to require surgery within five years, especially among those with knee OA. Cite this article: Bone Joint J 2022;104-B(7):792–800

Aims. Despite declining frequency of blood transfusion and electrolyte supplementation following total joint arthroplasty, postoperative blood analyses are still routinely ordered for these patients. This study aimed to determine the rate of blood transfusion and electrolyte restoration in arthroplasty patients treated with a perioperative blood conservation protocol and to identify risk factors that would predict the need for transfusion and electrolyte supplementation. Patients and Methods. Patients undergoing primary total joint arthroplasty of the hip or knee between July 2016 and February 2017 at a single institution were included in the study. Standard preoperative and postoperative laboratory data were collected and reviewed retrospectively. A uniform blood conservation programme was implemented for all patients. Need for blood transfusion or potassium supplementation was determined through a coordinated decision by the care team. Rates of transfusion and supplementation were observed, and patient risk factors were noted. Results. The overall rate of blood transfusion was 1.06% in the study population of 1132 total joint arthroplasties performed in 1023 patients. Of the 12 patients requiring transfusion, 11 were female, ten occurred in patients undergoing total hip arthroplasty, and all 12 patients had a preoperative haemoglobin level less than 130 g/l. Operative duration and surgical blood loss were significantly greater in those patients requiring blood transfusion. Nearly all patients requiring transfusion had a history of, or risk factors for, cardiovascular disease. Potassium supplementation was required in 15.5% of the study cohort; 72% of these patients receiving potassium presented with a potassium level less than 4 mmol/l during preoperative testing, while the remaining 28% had a past medical history of either significant anaemia, cardiopulmonary, cardiovascular, or renal diseases that had required substantial medical management. Conclusion. A consistent blood-conserving perioperative strategy effectively minimized need for blood transfusion in total joint arthroplasty patients below previously reported rates in the literature. We suggest that postoperative full blood counts and basic metabolic panels should not routinely be ordered in these patients unless their preoperative haemoglobin and potassium is below 130 g/dl or 4 mmol/l respectively, and they have medical comorbidities

Aims. To our knowledge, no study has compared the long-term results of cemented and hybrid total hip arthroplasty (THA) in patients with osteoarthritis (OA) secondary to congenital hip disease (CHD). This is a demanding procedure that may require special techniques and implants. Our aim was to compare the long-term outcome of cemented low-friction arthroplasty (LFA) and hybrid THA performed by one surgeon. Patients and Methods. Between January 1989 and December 1997, 58 hips (44 patients; one man, 43 woman; mean age 56.6 years (25 to 77)) with OA secondary to CHD were treated with a cemented Charnley LFA (group A), and 55 hips (39 patients; two men, 37 women; mean age 49.1 years (27 to 70)) were treated with a hybrid THA (group B), by the senior author (GH). The clinical outcome and survivorship were compared. Results. At all timepoints, group A hips had slightly better survivorship than those in group B without a statistically significant difference, except for the 24-year survival of acetabular components with revision for aseptic loosening as the endpoint, which was slightly worse. The survivorship was only significantly better in group A compared with group B when considering reoperation for any indication as the endpoint, 15 years postoperatively (74% vs 52%, p = 0.018). Conclusion. We concluded that there was not a substantial difference at almost any time in the outcome of cemented Charnley LFAs compared with hybrid THAs when treating patients with OA of the hip secondary to CHD. We believe, however, that after improvements in the design of components used in hybrid THA, this could be the method of choice, as it is technically easier with a shorter operating time. Cite this article: Bone Joint J 2019;101-B:1050–1057

Aims. The purpose of this study was to determine the access to and ability to use telemedicine technology in adult patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA), and to determine associations with the socioeconomic characteristics of the patients, including age, sex, race, and education. We also sought to understand the patients’ perceived benefits, risks, and preferences when dealing with telemedicine. Methods. We performed a cross-sectional survey involving patients awaiting primary THA and TKA by one of six surgeons at a single academic institution. Patients were included and called for a telephone-administered survey if their surgery was scheduled to be between 23 March and 2 June 2020, and were aged > 18 years. Results. The response rate was 52% (189 of 363 patients). A total of 170 patients (90.4%) reported using the internet, 177 (94.1%) reported owning a device capable of videoconferencing, and 143 (76.1%) had participated in a video call in the past year. When asked for their preferred method for a consultation, 155 (82.8%) and 26 (13.9%) ranked in-person and a videoconference as their first choice, respectively. The perceived benefits of telemedicine consultations included reduced travel to appointments (165 (88.2%) agreed) and reduced cost of attending appointments (123 (65.8%) agreed). However, patients were concerned that they would not establish the same patient-physician connection (100 (53.8%) agreed), and would not receive the same level of care (52 (33.2%) agreed) using telemedicine consultations compared with in-person consultations. Conclusion. Most patients undergoing arthroplasty have access to and are capable of using the technology required for telemedicine consultations. However, they still prefer in-person consultations due to concerns that they will not establish the same patient-physician connection and will not receive the same level of care, despite the benefits of reducing the time spent in travelling and the cost of attending appointments, and the appointments being easier to attend. Cite this article: Bone Joint J 2021;103-B(7 Supple B):98–102

Aims. The aim of this study was to determine whether patients with metal-on-metal (MoM) arthroplasties of the hip have an increased risk of cardiac failure compared with those with alternative types of arthroplasties (non-MoM). Patients and Methods. A linkage study between the National Joint Registry, Hospital Episodes Statistics and records of the Office for National Statistics on deaths was undertaken. Patients who underwent elective total hip arthroplasty between January 2003 and December 2014 with no past history of cardiac failure were included and stratified as having either a MoM (n = 53 529) or a non-MoM (n = 482 247) arthroplasty. The primary outcome measure was the time to an admission to hospital for cardiac failure or death. Analysis was carried out using data from all patients and from those matched by propensity score. Results. The risk of cardiac failure was lower in the MoM cohort compared with the non-MoM cohort (adjusted hazard ratio (aHR) 0.901; 95% confidence interval (CI) 0.853 to 0.953). The risk of cardiac failure was similar following matching (aHR 0.909; 95% CI 0.838 to 0.987) and the findings were consistent in subgroup analysis. Conclusion. The risk of cardiac failure following total hip arthroplasty was not increased in those in whom MoM implants were used, compared with those in whom other types of prostheses were used, in the first seven years after surgery. Cite this article: Bone Joint J 2018;100-B:20–7

Aims. Routine surveillance of primary hip and knee arthroplasties has traditionally been performed with office follow-up visits at one year postoperatively. The value of these visits is unclear. The present study aims to determine the utility and burden of routine clinical follow-up at one year after primary arthroplasty to patients and providers. Methods. All patients (473) who underwent primary total hip (280), hip resurfacing (eight), total knee (179), and unicompartmental knee arthroplasty (six) over a nine-month period at a single institution were identified from an institutional registry. Patients were prompted to attend their routine one-year postoperative visit by a single telephone reminder. Patients and surgeons were given questionnaires at the one-year postoperative visit, defined as a clinical encounter occurring at nine to 15 months from the date of surgery, regarding value of the visit. Results. Compliance with routine follow-up at one year was 35%. The response rate was over 80% for all questions in the patient and clinician surveys. Overall, 75% of the visits were for routine surveillance. Patients reported high satisfaction with their visits despite the general time for attendance, including travel, being over four hours. Surgeons found the visits more worthwhile when issues were identified or problems were addressed. Conclusion. Patient compliance with follow-up at one year postoperatively after primary hip and knee is low. Routine visits of asymptomatic patients deliver little practical value and represent a large time and cost burden for patients and surgeons. Remote strategies should be considered for routine postoperative surveillance primary hip and knee arthroplasties beyond the acute postoperative period. Cite this article: Bone Joint J 2020;102-B(7 Supple B):85–89

Aims. The hip’s capsular ligaments passively restrain extreme range of movement (ROM) by wrapping around the native femoral head/neck. We determined the effect of hip resurfacing arthroplasty (HRA), dual-mobility total hip arthroplasty (DM-THA), conventional THA, and surgical approach on ligament function. Materials and Methods. Eight paired cadaveric hip joints were skeletonized but retained the hip capsule. Capsular ROM restraint during controlled internal rotation (IR) and external rotation (ER) was measured before and after HRA, DM-THA, and conventional THA, with a posterior (right hips) and anterior capsulotomy (left hips). Results. Hip resurfacing provided a near-native ROM with between 5° to 17° increase in IR/ER ROM compared with the native hip for the different positions tested, which was a 9% to 33% increase. DM-THA generated a 9° to 61° (18% to 121%) increase in ROM. Conventional THA generated a 52° to 100° (94% to 199%) increase in ROM. Thus, for conventional THA, the capsule function that exerts a limit on ROM is lost. It is restored to some extent by DM-THA, and almost fully restored by hip resurfacing. In positions of low flexion/extension, the posterior capsulotomy provided more normal function than the anterior, possibly because the capsule was shortened during posterior repair. However, in deep flexion positions, the anterior capsulotomy functioned better. Conclusion. Native head-size and capsular repair preserves capsular function after arthroplasty. The anterior and posterior approach differentially affect postoperative biomechanical function of the capsular ligaments. Cite this article: Bone Joint J 2019;101-B:426–434

Total hip replacement (THR) still is a rare intervention in many African countries. In Burkina Faso it is not performed on a regular basis. A visiting programme for THR was started in a district hospital with no previous relevant experience. In this paper we present an analysis of the surgical technical problems and peri-operative complications of 152 THRs in 136 patients and three bipolar hemiarthroplasties in three patients undertaken in this new programme with limited orthopaedic equipment. There were 86 male and 53 female patients with a mean age of 49 years (21 to 78). We identified 77 intra-operative technical problems in 51 operations. There were 24 peri-operative complications in 21 patients, 17 of which were bony in nature. So far, ten revision THRs have been performed in nine patients.

Regular analysis of the technical problems and complications was used to improve quality, and we identified patient selection adapted to the local circumstances as important to avoid complications. Our reflections on the problems encountered in initiating such a programme may be of help to other teams planning similar projects.

Cite this article: Bone Joint J 2014;96-B:177–80.

In Africa the amount of joint replacement surgery is increasing, but the indications for operation and the age of the patients are considerably different from those in the developed world. New centres with variable standards of care and training of the surgeons are performing these procedures and it is important that a proper audit of this work is undertaken. In Malawi, we have pioneered a Registry which includes all joint replacements that have been carried out in the country. The data gathered include the age, gender, indication for operation, the prosthesis used, the surgical approach, the use of bone graft, the type of cement, pressurising systems and the thromboprophylaxis used. All patients have their clinical scores recorded pre-operatively and then after three and six months and at one year. Before operation all patients are counselled and on consent their HIV status is established allowing analysis of the effect of HIV on successful joint replacement. To date, 73 total hip replacements (THRs) have been carried out in 58 patients by four surgeons in four different hospitals. The most common indications for THR were avascular necrosis (35 hips) and osteoarthritis (22 hips). The information concerning 20 total knee replacements has also been added to the Registry

Arthroscopy of the native hip is an established diagnostic and therapeutic procedure. Its application in the symptomatic replaced hip is still being explored. We describe the use of arthroscopy of the hip in 24 symptomatic patients following total hip replacement, resurfacing arthroplasty of the hip and partial resurfacing (study group), and compared it with arthroscopy of the native hip in 24 patients (control group). A diagnosis was made or confirmed at arthroscopy in 23 of the study group and a therapeutic arthroscopic intervention resulted in relief of symptoms in ten of these. In a further seven patients it led to revision hip replacement. In contrast, arthroscopy in the control group was diagnostic in all 24 patients and the resulting arthroscopic therapeutic intervention provided symptomatic relief in 21. The mean operative time in the study group (59.7 minutes (35 to 93)) was less than in the control group (71 minutes (40 to 100), p = 0.04) but the arthroscopic approach was more difficult in the arthroplasty group. We suggest that arthroscopy has a role in the management of patients with a symptomatic arthroplasty when other investigations have failed to provide a diagnosis

Aims. Our aim was to examine the Elixhauser and Charlson comorbidity indices, based on administrative data available before surgery, and to establish their predictive value for mortality for patients who underwent hip arthroplasty in the management of a femoral neck fracture. Patients and Methods. We analyzed data from 42 354 patients from the Swedish Hip Arthroplasty Register between 2005 and 2012. Only the first operated hip was included for patients with bilateral arthroplasty. We obtained comorbidity data by linkage from the Swedish National Patient Register, as well as death dates from the national population register. We used univariable Cox regression models to predict mortality based on the comorbidity indices, as well as multivariable regression with age and gender. Predictive power was evaluated by a concordance index, ranging from 0.5 to 1 (with the higher value being the better predictive power). A concordance index less than 0.7 was considered poor. We used bootstrapping for internal validation of the results. Results. The predictive power of mortality was poor for both the Elixhauser and Charlson comorbidity indices (concordance indices less than 0.7). The Charlson Comorbidity Index was superior to Elixhauser, and a model with age and gender was superior to both indices. Conclusion. Preoperative comorbidity from administrative data did not predict mortality for patients with a hip fracture treated by arthroplasty. This was true even if association on group level existed

Nerve palsy is a well-described complication following total hip arthroplasty, but is highly distressing and disabling. A nerve palsy may cause difficulty with the post-operative rehabilitation, and overall mobility of the patient. Nerve palsy may result from compression and tension to the affected nerve(s) during the course of the operation via surgical manipulation and retractor placement, tension from limb lengthening or compression from post-operative hematoma. In the literature, hip dysplasia, lengthening of the leg, the use of an uncemented femoral component, and female gender are associated with a greater risk of nerve palsy. We examined our experience at a high-volume, tertiary care referral centre, and found an overall incidence of 0.3% out of 39 056 primary hip arthroplasties. Risk factors found to be associated with the incidence of nerve palsy at our institution included the presence of spinal stenosis or lumbar disc disease, age younger than 50, and smoking. If a nerve palsy is diagnosed, imaging is mandatory and surgical evacuation or compressive haematomas may be beneficial. As palsies are slow to recover, supportive care such as bracing, therapy, and reassurance are the mainstays of treatment. Cite this article: Bone Joint J 2017;99-B(1 Supple A):46–9

We studied survival to 38 years after Charnley low-friction arthroplasty of the hip. We used revision as an end-point, while adopting a policy of regular follow-up and early revision for radiological changes alone if indicated. Between November 1962 and June 2005, 22 066 primary low-friction arthroplasties (17 409 patients) had been performed at Wrightington Hospital by more than 330 surgeons. By June 2006, 1001 (4.5%) hips had been revised and 1490 patients (2662 hips, 12%) had died. At 31 years, where a minimum of 40 hips were still attending follow-up, survival with revision for infection as an endpoint was 95%, for dislocation 98%, for a fractured stem 88.6%, for a loose stem 72.5% and for a loose acetabular component 53.7%. Wear and loosening of the ultra-high-molecular-weight polyethylene acetabular component were the main long-term problems. We conclude that regular follow-up after hip replacement is essential and that all operative findings should be recorded at revision

As adverse events related to metal on metal hip arthroplasty have been better understood, there has been increased interest in toxicity related to the high circulating levels of cobalt ions. However, distinguishing true toxicity from benign elevations in cobalt levels can be challenging. The purpose of this review is to examine the use of cobalt alloys in total hip arthroplasty, to review the methods of measuring circulating cobalt levels, to define a level of cobalt which is considered pathological and to review the pathophysiology, risk factors and treatment of cobalt toxicity. To the best of our knowledge, there are 18 published cases where cobalt metal ion toxicity has been attributed to the use of cobalt-chromium alloys in hip arthroplasty. Of these cases, the great majority reported systemic toxic reactions at serum cobalt levels more than 100 μg/L. This review highlights some of the clinical features of cobalt toxicity, with the goal that early awareness may decrease the risk factors for the development of cobalt toxicity and/or reduce its severity. Take home message: Severe adverse events can arise from the release of cobalt from metal-on-metal arthroplasties, and as such, orthopaedic surgeons should not only be aware of the presenting problems, but also have the knowledge to treat appropriately. Cite this article: Bone Joint J 2016;98-B:14–20

Aims. For this retrospective cohort study, patients aged ≤ 30 years (very young) who underwent total hip arthroplasty (THA) were compared with patients aged ≥ 60 years (elderly) to evaluate the rate of revision arthroplasty, implant survival, the indications for revision, the complications, and the patient-reported outcomes. Patients and Methods. We retrospectively reviewed all patients who underwent primary THA between January 2000 and May 2015 from our institutional database. A total of 145 very young and 1359 elderly patients were reviewed. The mean follow-up was 5.3 years (1 to 18). Logistic generalized estimating equations were used to compare characteristics and the revision rate. Survival was evaluated using Kaplan–Meier curves and hazard rates were created using Cox regression. Results. The overall revision rate was 11% (16/145) in the very young and 3.83% (52/1359) in the elderly groups (odds ratio (OR) 2.58, 95% confidence interval (CI) 1.43 to 4.63). After adjusting for the American Society of Anesthesiologists (ASA) score, gender, and a history of previous surgery in a time-to-event model, the risk of revision remained greater in the very young (adjusted hazard ratio (HR) 2.48, 95% CI 1.34 to 4.58). Survival at ten years was 82% (95% CI, 71 to 89) in the very young and 96% (95% CI, 94 to 97) in the elderly group (p < 0.001). The very young had a higher rate of revision for complications related to metal-on-metal (MoM) bearing surfaces (p < 0.001). At last follow-up, the very young group had higher levels of physical function (p = 0.002), lower levels of mental health (p = 0.001), and similar levels of pain (p = 0.670) compared with their elderly counterparts. Conclusion. The overall revision rate was greater in very young THA patients. This was largely explained by the use of MoM bearings. Young patients with non-MoM bearings had high survivorship with similar complication profiles to patients aged ≥ 60 years. Cite this article: Bone Joint J 2018;100-B:867–74

In patients with severe quadriplegic cerebral palsy and painful hip dislocation proximal femoral resection arthroplasty can reduce pain, but the risk of heterotopic ossification is significant. We present a surgical technique of autologous capping of the femoral stump in order to reduce this risk, using the resected femoral head as the graft. A retrospective study of 31 patients (43 hips) who had undergone proximal femoral resection arthroplasty with (29 hips) and without autologous capping (14 hips) was undertaken. Heterotopic ossification was less frequent in patients with autologous capping, and a more predictable pattern of bony overgrowth was found. For a selected group of non-ambulatory patients with long-standing painful dislocation of the hip, we recommend femoral resection arthroplasty over more complicated reconstructive operations. The risk of heterotopic ossification, which is a major disadvantage of this operation, is reduced by autologous capping

We reviewed 261 patients with 320 Charnley low-friction arthroplasties who had a mean follow-up of 22 years 10 months (20 to 30). Of these, 93.9% considered the operation to be a success; 82.3% were free from pain and 11.6% had occasional discomfort. Satisfactory function was achieved in 59.6% and 62% had an excellent range of movement. The clinical results did not correlate well with the radiological appearance; radiologically loose components did not affect the clinical outcome. The main long-term problem was wear and loosening of the UHMWPE cup. Our findings suggest that the radiological appearance of the arthroplasty is a more reliable indication of the state of the arthroplasty than the clinical results

Few independent studies have reported the outcome of resurfacing arthroplasty of the hip. The aim of this study was to report the five-year clinical outcome and seven-year survival of an independent series. A total of 610 Birmingham Hip Resurfacing arthroplasties were performed in 532 patients with a mean age of 51.8 years (16.5 to 81.6). They were followed for between two and eight years; 107 patients (120 hips) had been followed up for more than five years. Two patients were lost to follow-up. At a minimum of five years’ follow-up, 79 of 85 hips (93%) had an excellent or good outcome according to the Harris hip score. The mean Oxford hip score was 16.1 points (. sd. 7.7) and the mean University of California Los Angeles activity score was 6.6 points (. sd. 1.9). There were no patients with definite radiological evidence of loosening or of narrowing of the femoral neck exceeding 10% of its width. There were 23 revisions (3.8%), giving an overall survival of 95% (95% confidence interval 85.3 to 99.2) at seven years. Fractured neck of femur in 12 hips was the most common indication for revision, followed by aseptic loosening in four. In three hips (three patients) (0.5%), failure was possibly related to metal debris. Considering that these patients are young and active these results are good, and support the use of resurfacing. Further study is needed to address the early failures, particularly those related to fracture and metal debris