Revision surgery is an important outcome of hip and knee arthroplasty among patients with osteoarthritis (OA). The objective of this study was to determine the risk of revision over time in a large, geographically defined population in North America, and to assess the effects of age, sex, and socioeconomic status (SES) on knee and hip revision rates in this population.

We used data on admissions to all acute care hospitals in British Columbia (BC), Canada (population of four million people) from 1986 until 2004 (eighteen years of follow-up). Primary knee and hip replacement surgery for OA and revision procedures were identified using diagnostic (ICD-9, ICD-10) codes and surgical procedure codes. We excluded cases admitted due to injury or neoplasm. SES was assigned based on residential address linked to census data at the level of enumeration area (ecological variable), and analyzed according to quintiles or deciles of the distribution. In the analysis, we used Kaplan-Meier survival curves to describe the risk of first revision following first primary replacement surgery over time and parametric (Weibull) survival regression models to analyze the effects of joint (hip vs. knee) age, sex, and SES on revision rates. Death, emigration, and another primary joint replacement were treated as censoring events.

Between 1986 and 2004, we observed 24,169 first primary hip replacements and 22,875 first primary knee replacements. In these patients, there were 1,313 hip revisions and 914 knee revisions following a primary replacement. The risk of revision at five, ten and fifteen years after primary replacement according to joint and sex were identified The overall risks were 10.1% for the hip and 8.7% for the knee at ten years, and 15.5% and 14.7%, respectively, at fifteen years. Risk of revision (%) following first primary joint replacement surgery Hip Knee Years Men Women Men Women 5 5.0 3.9 4.6 3.8 10 11.0 9.4 9.7 8.0 15 17.8 14.1 18.5 12.4 In a multivariate survival regression model including joint, age, sex, and SES, only age and sex were significantly associated with revisions. The hazard ratio was 1.2 for men compared with women (p< 0.0001). Revision rates were higher in younger persons, with hazard ratios increasing from 1.7 for age 70–79 (p< 0.0001) to 3.9 for age < 49 (p< 0.0001) compared with age 80+. After adjusting for age and sex, SES was not significantly associated with revision risk following primary hip or knee replacement surgery in this population (p=0.75).

This is one of the largest and longest cohort studies in North America to look at the epidemiology of revision procedures following hip and knee replacement for OA. Higher rates in men and in younger persons are consistent with previous reports. The lack of association between revision risk and SES in BC is an important finding given current concerns about socioeconomic disparities in access to and outcomes of treatment for OA.

Purpose: To evaluate the benefits of standardization on the reliability of the physical examination of the hip by rheumatologists and orthopaedic surgeons

Methods: Six subjects with mild to severe hip osteoarthritis (OA) were examined by 6 examiners (4 rheumatologists, 2 orthopedic surgeons) experienced in the assessment of hip OA using a 6x6 Latin square design. Subjects were examined, followed by a standardization meeting and, a day later, by post-standardization examinations. 33 hip examination maneuvers were evaluated, including range of motion, pain, tenderness, muscle strength, leg length and gait. The order of examinations was randomized for each examiner. For dichotomous signs, agreement was calculated as the prevalence-adjusted bias-adjusted kappa (PABAK). Ordinal and continuous variables were analyzed by ANOVA, using the proportion of variance due to rheumatologists to calculate a reliability coefficient (Rc).

Results: Subjects’ mean age was 61 years (range 49–65), mean BMI was 24 (range 21–30), mean WOMAC pain on walking was 52 mm (range 21–81mm). 23/33 (70%) hip examinations were reliable after standardization. Two new items resulted from the standardization meeting. Pre-/post-standardization reliability for select hip examinations using PABAK were as follows: Gait 0.06/0.52; pain on internal rotation 0.60/0.52; pain on external rotation 0.24/0.72; pain on flexion 0.46/0.82; Patrick test for hip pain 0.78/0.80; Thomas test 0.60/0.88; Trendelenburg test 0.36/0.06. Pre-/post-standardization reliability for select hip examinations using Rc were as follows: hip flexion strength 0.83/0.95; hip abduction strength 0.90/0.86; hip adduction strength 0.87/0.86; ROM internal rotation (supine) 0.87/0.94; ROM external rotation (supine) 0.87/0.80.

Conclusions: Moderate to very good agreement was present for many hip examinations prior to standardization. Improved reliability was achieved after standardization for many but not all hip assessments. This will be important for improved outcome studies of early hip OA.

Purpose: To evaluate the effect of outpatient physiotherapy versus a self-adminstered home exercise program on recovery following primary total hip arthroplasty.

Methods: Subjects awaiting primary total hip arthroplasty consented to participate in this prospective randomized clinical trial. Patients were assigned to participate in either an outpatient physiotherapy program or self-administered/self-directed home exercise program following discharge home from hospital. Multiple longitudinal measures were performed to adequately assess recovery over time. Primary outcome for comparison was WOMAC function at 4 months postoperatively, additional outcomes of timed-up-and-go, SF-36, HUI3, FSI. Primary outcome was evaluated using repeated measures analyses and regression models for longitudinal data.

Results: 100 patients were randomized to their respective interventions. The two cohorts were similar with regards to baseline characteristics of age, gender, and pre-op quality of life measures (p> .05). At 4 months post-op both groups demonstrated significant change from baseline function and were similar with regards to recovery and rate of recovery (p> .05).

Conclusions: While all patients demonstrated excellent recovery, patients receiving self-adminstered home exercise program did not demonstrate inferior outcome at the interval(s) assessed. Self-adminstered home exercise program may be an effective alternative rehabilitation program where physiotherapy services are limited or in specific subgroups of patients.

Funding : Educational Grant from the Canadian Orthopaedic Foundation