Robert B. Bourne

Patient Satisfaction after Total Knee Arthroplasty: Who is Satisfied and Who is Not?

Despite substantial advances in primary TKA, numerous studies using historic TKA implants suggest only 82% to 89% of primary TKA patients are satisfied. We reexamined this issue to determine if contemporary TKA implants might be associated with improved patient satisfaction. We performed a cross-sectional study of patient satisfaction after 1703 primary TKAs performed in the province of Ontario. Our data confirmed that approximately one in five (19%) primary TKA patients were not satisfied with the outcome. Satisfaction with pain relief varied from 72–86% and with function from 70–84% for specific activities of daily living. The strongest predictors of patient dissatisfaction after primary TKA were expectations not met (10.7× greater risk), a low 1-year WOMAC (2.5× greater risk), preoperative pain at rest (2.4× greater risk) and a postoperative complication requiring hospital readmission (1.9× greater risk).Level of Evidence: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Efficacy of periarticular multimodal drug injection in total knee arthroplasty. A randomized trial.

BACKGROUND Postoperative analgesia with the use of parenteral opioids or epidural analgesia can be associated with troublesome side effects. Good perioperative analgesia facilitates rehabilitation, improves patient satisfaction, and may reduce the hospital stay. We investigated the analgesic effect of locally injected drugs around a total knee prosthesis. METHODS Sixty-four patients undergoing total knee arthroplasty were randomized either to receive a periarticular intraoperative injection containing ropivacaine, ketorolac, epimorphine, and epinephrine or to receive no injection. The perioperative analgesic regimen was standardized. All patients in both groups received patient-controlled analgesia for twenty-four hours after the surgery, and this was followed by standard analgesia. Visual analog scores for pain, during activity and at rest, and for patient satisfaction were recorded preoperatively and postoperatively and at the six-week follow-up examination. The consumption of patient-controlled analgesia at specific postoperative time-points and the overall analgesic requirement were measured. RESULTS The patients who had received the injection used significantly less patient-controlled analgesia at six hours, at twelve hours, and over the first twenty-four hours after the surgery. In addition, they had higher visual analog scores for patient satisfaction and lower visual analog scores for pain during activity in the post-anesthetic-care unit and four hours after the operation. No cardiac or central nervous system toxicity was observed. CONCLUSIONS Intraoperative periarticular injection with multimodal drugs can significantly reduce the requirements for patient-controlled analgesia and improve patient satisfaction, with no apparent risks, following total knee arthroplasty.

Surgical approach, abductor function, and total hip arthroplasty dislocation.

Dislocation is a leading early complication of total hip arthroplasty. The effect of surgical approach on instability and abductor function is a controversial topic. A comprehensive literature review was done to evaluate the correlation of surgical approach and primary total hip arthroplasty dislocation. Two hundred sixty clinical studies were identified between 1970 and 2001. Four prospective studies were identified but individually they contained insufficient power or control groups to reach statistical significance regarding surgical approach and dislocation. Fourteen studies involving 13,203 primary total hip arthroplasties met the inclusion criteria based on variables previously shown to affect stability. These studies were evaluated with respect to surgical approach and dislocation. The combined dislocation rate for these studies was 1.27% for the transtrochanteric approach, 3.23% for the posterior approach (3.95% without posterior repair and 2.03% with posterior repair), 2.18% for the anterolateral approach, and 0.55% for the direct lateral approach. Eight studies involving 2455 primary total hip arthroplasties evaluated postoperative limp. The incidence of postoperative limp was 4% to 20% for patients who had the lateral approach and 0% to 16% for patients who had the posterior approach. The quality of the literature regarding surgical approach, dislocation rates, and abductor function is limited. Larger controlled prospective studies are needed to investigate the potential benefits of the posterior approach in lieu of a dislocation rate six times higher than the direct lateral approach for primary total hip arthroplasty.

Extensor Mechanism Complications Following Total Knee Arthroplasty

Extensor mechanism complications following 281 knee arthroplasties that included patellar resurfacing, performed by two surgeons in one hospital over a 6-year period, were reviewed. The mean follow-up period was 42 months. There were 28 (10%) extensor mechanism complications: 3 quadriceps tendon ruptures, 5 patellar fractures, 4 patellar tendon ruptures, 11 recurring patellar subluxations, 4 cases of patellar pain, and 1 malrotated patella. Nine (3%) required further surgery. Surgical technique may have contributed to the tendon ruptures; patellar fractures occurred mainly in patients who had rheumatoid arthritis. Patients with patellar subluxation had abnormal preoperative valgus deformities of their knees and presented with this subluxation problem an average of 4 months after surgery, but it appeared to cause them less discomfort with time. Patellar resurfacing as part of a knee arthroplasty procedure is recommended but should be performed with care to the integrity and vasculature of the extensor mechanism.

Survivorship of the High Tibial Valgus Osteotomy A 10-to 22-Year Followup Study

The results of 106 high tibial valgus osteotomies in 85 patients were evaluated after a minimum 10-year followup to determine survivorship, complications, and risk factors associated with failure. Using Kaplan-Meier survivorship analysis, 73% of patients at 5 years, 51% of patients at 10 years, 39% at 15 years, and 30% at 20 years after high tibial osteotomy had not required conversion of the high tibial osteotomy to a total knee arthroplasty. Univariate Cox regression analysis of risk factors showed that age older than 50 years, previous arthroscopic debridement, presence of a lateral tibial thrust, preoperative knee flexion less than 120 degrees, insufficient valgus correction, and development of delayed union or nonunion were significantly associated with probability of early failure. Multivariate Cox regression analysis showed that a body mass index of less than 25 kg/m2, presence of a lateral tibial thrust, and development of delayed union or nonunion were significantly associated with probability of early failure. Using recursive partitioning analysis of risk factors with the Wilcoxon test, a subset of patients who were younger than 50 years of age and who had preoperative knee flexion greater than 120 degrees had a probability of survival after high tibial osteotomy approaching 95% at 5 years, 80% at 10 years, and 60% at 15 years. These results suggest that survival of high tibial osteotomy can be improved through careful patient selection and surgical technique.

Tibial post wear in posterior stabilized total knee arthroplasty. An unrecognized source of polyethylene debris.

Background: With extensive use of posterior stabilized total knee arthroplasty implants, it is increasingly important to assess the mechanical performance of this design alternative. The purpose of this study was to examine the wear patterns at the femoral cam-tibial post interface in a series of posterior stabilized prostheses retrieved at revision arthroplasty. Methods: Qualitative and quantitative wear analysis was performed over the surface of the stabilizing posts from twenty-three retrieved total knee components that had been implanted for a mean of 35.6 months (range, 2.3 to 107.2 months). The implants were designs from four different manufacturers. Digital images of the anterior, posterior, medial, and lateral surfaces of the tibial post were made for quantitative analysis and determination of a post wear score. Wear was characterized with a grading system that isolates adhesive, abrasive, and fatigue wear, inferring a weighted score from an estimation of generated polyethylene debris. Results: Evidence of wear or damage was observed on all twenty-three of the stabilizing posts, including those revised because of infection. On the average, 39.9% (range, 18.5% to 60%) of the post surface demonstrated some form of deformation, with adhesive wear, or burnishing, being the predominant wear mechanism. Seven posts (30%) exhibited severe damage with gross loss of polyethylene. The wear caused premature failure and early revision of two components: one of these failures was related to isolated post wear and the other, to severe post wear and subsequent fracture. Overall, wear was primarily posterior, but wear over the anterior, medial, and lateral surfaces was also notable. Conclusions: The cam-post articulation in posterior stabilized implants can be an additional source of polyethylene wear debris. The variability in wear patterns observed among designs may be due to differences in cam-post mechanics, post location, and post geometry. The surgeon should be aware that the cam-post interface is not an innocuous articulation, and manufacturers should be motivated to produce implants that maintain the function of the post while limiting wear and surface damage.

Mobile-bearing knee replacement: concepts and results.

In summary, if TKRs are to be performed in patients who are younger and more active than those who had the initial procedures in the 1970s and 1980s, better wear performance is imperative for long-term durability, especially if surgeons continue to consider the versatility associated with modular knee-replacement systems to be a necessity. At least with some designs, including the Oxford knee and the LCS knee, the results after a minimum follow-up of 10 years are comparable with the best results after arthroplasty with fixed-bearing designs in terms of wear, loosening, and osteolysis (Table 7). As with fixed-bearing designs, there are additional challenges in terms of optimizing bearing-surface conformity and improving kinematics. Improvements in future designs of mobile-bearing total knee replacements should include better control of bearing mobility patterns to reduce the prevalence of the abnormal kinematic motions that have been observed in fluoroscopic evaluations.

Deep-vein thrombosis and continuous passive motion after total knee arthroplasty

Seventy-five of 150 consecutive patients who underwent total knee arthroplasty had routine physiotherapy and seventy-five had continuous passive motion of the lower limb that had been operated on as well as routine physiotherapy. A pulmonary embolus did not develop in any patient, but about 40 per cent had thrombosis in the veins of the calf, whether passive motion had been administered or not. Radiographically, the deep-vein thrombosis was seen to extend into or proximal to the popliteal vessel in 5 per cent of the patients in each group. Sex, age, obesity, or a history of hypertension or diabetes did not influence the incidence of venous thrombosis, but there was a higher incidence in patients in whom cement was used for fixation of the total knee components, irrespective of the use of continuous passive motion of the limb.

Soft-tissue balancing of the hip: the role of femoral offset restoration.

Inadequate soft-tissue balancing is a major yet often underemphasized cause of failure for primary and revision total hip arthroplasty. Accordingly, contemporary cemented and cementless hip prostheses have been designed with consideration of this issue, and this has substantially increased the long-term survival of total hip replacements. Therefore, it is important for orthopaedic surgeons to be familiar with the rationale, biomechanical principles, and clinical implications associated with soft-tissue balancing of the hip as well as strategies to avoid inadequate soft-tissue balancing and systematic techniques to restore adequate soft-tissue tensioning during total hip arthroplasty.

Wear rate of highly cross-linked polyethylene in total hip arthroplasty. A randomized controlled trial.

BACKGROUND Highly cross-linked polyethylene was introduced for clinical use in total hip arthroplasty with the expectation that it would exhibit less wear when compared with conventional polyethylene. The purpose of this study was to report the clinical and radiographic results, after a minimum of five years of follow-up, of a randomized, blinded, controlled trial comparing a conventional polyethylene with a first-generation highly cross-linked polyethylene. METHODS One hundred patients were enrolled in a prospective, randomized controlled study comparing highly cross-linked and conventional polyethylene acetabular liners in total hip arthroplasty. Fifty patients were in each group. At the time of follow-up, clinical outcomes were assessed and steady-state femoral head penetration rates (after bedding-in) for each patient were calculated with use of a validated radiographic technique. In addition, a statistical comparison of polyethylene wear between groups was performed with use of generalized estimating equations. RESULTS At a mean of 6.8 years postoperatively, there were no differences between the two polyethylene groups with regard to the Harris hip score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), or Short Form-12 (SF-12) score. The mean femoral head penetration rate in the first through fifth years was found to be significantly lower in the group treated with the highly cross-linked polyethylene (0.003 mm/yr [95% confidence interval, +/-0.027]) than it was in the group treated with conventional polyethylene (0.051 mm/yr [95% confidence interval, +/-0.022]) (p=0.006). Men treated with a conventional polyethylene liner had a significantly higher (p<or=0.012) femoral head penetration rate (0.081 mm/yr [95% confidence interval, +/-0.065]) than both men and women with a highly cross-linked liner (-0.013 mm/yr [95% confidence interval, +/-0.074] and 0.009 mm/yr [95% confidence interval, +/-0.028], respectively). The general estimating equations demonstrated that the group with a highly cross-linked polyethylene liner had a significantly lower femoral head penetration rate than the group with a conventional polyethylene liner (p=0.025), and a significantly higher femoral head penetration rate was demonstrated in men with a conventional polyethylene liner when compared with both men and women with a highly cross-linked liner (p=0.003). CONCLUSIONS At a minimum of five years postoperatively, the steady-state femoral head penetration rate associated with this first-generation highly cross-linked polyethylene liner was significantly lower than that associated with a conventional polyethylene liner. Long-term follow-up is required to demonstrate the clinical benefit of this new material.