Several factors have been identified that may affect outcome after total knee replacement (TKR). We performed a systematic review of studies that looked at the association of pre-operative factors and outcome after primary total knee replacement for osteoarthritis. All study types that investigated TKR for osteoarthritis were considered except retrospective case-series. Studies that included patients undergoing revision TKR were excluded if they did not provide separate results for primary and revision knee replacement. Any patient factor that was measured in the pre-operative period was included. The factors measured included age, sex, race, income, body mass index (BMI), medical or joint co-morbidity, level of education, disease specific scores and their subcategories and general health scores. Studies that recorded outcome measures were only included if evidence of validation for use after total knee replacement was available. We identified 590 studies purporting to evaluate TKR for OA. Of these, 25 studies were retrieved for in-depth consideration and 10 were found to meet the inclusion criteria. Most of these were cohort studies that used some form of regression analysis. The results showed that the strongest and most consistent correlations were between pre-operative pain scores, pre-operative function scores, co-morbidity and post-operative function scores. Age, gender and level of education were not significant predictors of outcome. However, even the best models could only predict 36% of the variance in outcome. Understanding which factors influence outcome the most will be of great benefit to patients and those who plan and deliver healthcare.
Hip and knee arthroplasty has been associated with relatively high rates of thromboembolic events and the majority of UK orthopaedic surgeons use at least one form of prophylaxis. Of the many different subgroups of thromboembolic rates that are commonly presented in the literature, symptomatic proximal deep vein thrombosis (spDVT) and fatal pulmonary embolism (fPE) are perhaps the most important clinical outcomes. To determine the effectiveness of common chemical and mechanical prophylactic methods in preventing spDVT and fPE in patients undergoing primary hip and knee arthroplasty. A systematic review of the literature from 1981 to December 2002 was performed. Predetermined inclusion and exclusion criteria were applied. Studies where more than one method of prophylaxis was used were excluded from analysis. For each individual method of prophylaxis, data was extracted, combined and converted to give estimates of the rates of spDVT, fPE and major bleeding events. Absolute risk reduction estimates for spDVT, fPE and major bleeding events were calculated by comparing the thromboembolic rates for each method of prophylaxis with using no prophylaxis of any kind. 992 studies were identified of which 162 met the inclusion criteria. No method of prophylaxis was statistically significantly more effective at preventing spDVT and fPE than using nothing. There were at least as many major bleeding complications as spDVTs. The number of fPEs prevented was very small. When complications such as major bleeding are considered, the evidence behind the use of any prophylaxis is unconvincing.
