With the rising demand for primary total hip arthroplasty (THA), there has been an emphasis on reducing the revision burden and improving patient outcomes. Although studies have shown that primary THA effectively minimizes pain and restores normal hip function for activities of daily living, many younger patients want to participate in more demanding activities after their operation. With IRB approval, 2 groups of subjects were enrolled in this study: (i) 143 patients at an average of 25 months (range 10–69 months) post-primary THA, and (ii) 165 control subjects with no history of hip surgery or hip pathology. All subjects were assigned to one of four categories according to their age and gender: Group A: 40–60 year old males (31 THA; 42 Controls), Group B: 40–60 year old females (25 THA; 53 Controls), Group C: 60–80 year old males (35 THA; 25 Controls), and Group D: 60–80 year old females (36 THA; 23 Controls). Each patient completed a self-administered Hip Function Questionnaire (HFQ) which assessed each subject's satisfaction, expectations, symptoms and ability to perform a series of 94 exercise, recreational and daily living activities. These included participation in work-out activities, adventure and water sports, running and biking, and contact and team sports. Each participant was also asked their activity frequency, symptom prevalence and satisfaction with their hip in performing each activity.Background
Methods
Despite all the attention to new technologies and sophisticated implant designs, imperfect surgical technique remains a obstacle to improving the results of total knee replacement (TKR). On the tibial side, common errors which are known to contribute to post-operative instability and reduced function include internal rotation of the tibial tray, inadequate posterior slope, and excessive component varus or valgus. However, the prevalence of each error in surgeries performed by surgeons and trainees is unknown. The following study was undertaken to determine which of these errors occurs most frequently in trainees acquiring the surgical skills to perform TKR. A total of 43 knee replacement procedures were performed by 11 surgical trainees (surgical students, residents and fellows) in a computerized training center. After initial instruction, each trainee performed a series of four TKR procedures in cadavers (n = 2) and bone replicas (n = 2) using a contemporary TKR instrument set and the assistance of an experienced surgical instructor. Prior to each procedure, computer models of each cadaver and/or bone replica tibia were prepared by reconstructing CT scans of each specimen. All training procedures were performed in a navigated operating room using a 12 camera motion analysis system (Motion Analysis Inc.) with a spatial resolution in all three orthogonal directions of ± 0.15 mm. The natural slope, varus/valgus alignment, and axial rotation of the proximal tibial surface were recorded prior to surgery and after placement of the tibial component. For evaluation of all data, acceptable limits for implantation were defined as: posterior slope: 0–10°; varus/valgus inclination of tibial resection: ± 3°; and external rotation: 0–10°.Introduction:
Materials and Methods:
The new Knee Society Score has been developed and validated, in part, to characterize better the expectations, components of satisfaction, and the physical activities of the younger, more diverse modern population of TKA patients. This study aims to reveal patients' activity levels' post-TKA and to determine how it contributes to their subjective evaluation of the surgery. As part of a multi-centered and regionally diverse study sponsored by the Knee Society, the new Knee Society Score (KSS) was administered 243 patients (44% male; avg 66.4years; 56% female, avg 67.7years) following primary TKA (follow up > 1year, avg. 25mos). The new, validated KSS questionnaire consists of a traditional objective component, as well as subjective components inquiring into patient symptoms, satisfaction, expectations and activity levels as well as a survey of three physical activities that are viewed as important to the patients. Responses were analyzed as a whole group and as subgroups of male and female and as younger (<65) and older (>65).Introduction
Methods
Joint Registries are a valuable resource for defining the survivorship of prostheses and procedures undertaken for the treatment of joint disease. However, the use of this data as a basis for advocating specific implant designs is controversial because of the confounding effects of variations in patient selection, the training, skill and experience of surgeons, and the priorities of individual patients. Despite these challenges, the Australian Joint Registry has utilized its early survivorship data to identify specific designs that are expected to exhibit lower than average durability in the long term. The aim of this study was to assess the accuracy of this practice in identifying implants providing inferior long-term performance. Over the period 2004–8, the Australian Registry identified 48 prosthetic components used in primary THA, HRA, TKA or UKA which exhibited a statistically significant increase in the early revision rate. For each of these components, we compared the rate of revisions per 100 “component-years” when it was first identified by the Registry, to its ultimate fiveyear cumulative survival in 2008. These survival parameters were also compared to average values based on procedure (eg.THR) and fixation method (i.e. cemented, cementless, hybrid). Regression analysis was performed to determine the accuracy of initial relative revisions per 100 OCY as a predictive measure of eventual component revision rate. Five year survival data was available on 30 of the 48 implants identified by the registry. There was a strong correlation (R2=0.9614) between initial revisions per 100 component-years and the 5-yr survival of the identified designs. 29 of 30 designs (97%) exhibited lower than average survivorship at 5 years. Six designs (20%) had failure rates within 2% of average values, and 7 (23%) had a 5–year failure rate less than 50% above average values. Although, when identified by the Registry, 80% of identified components exceeded the average rate of revision by 100%, only 60% displayed more than twice the cumulative revision rate at 5 years post-op. These results demonstrate that early data collected by Joint Registries can form the basis of accurate identification of designs which ultimately prove to be clinically unsuccessful. Predictions made by the Australian Registry concerning inferior designs have an accuracy of approximately 80%. Further work is recommended to enhance the valuable potential of Registry data in predicting the outcome of both implants and procedures.
