Leesa D. Harty

Predicting range of motion after total knee arthroplasty. Clustering, log-linear regression, and regression tree analysis.

Background: Range of motion is a crucial measure of the outcome of total knee arthroplasty. The purpose of this study was to determine which factors are predictive of the postoperative range of motion. Methods: We retrospectively studied 3066 patients (4727 knees) who had a primary total knee arthroplasty with the same type of implant at the same center between 1983 and 1998. Statistical clustering analysis paired with log-linear regression was used to determine groupings along continuous variables. Regression tree analysis was used to characterize the combinations of variables influencing the postoperative range of motion. The variables considered were preoperative and intraoperative flexion and extension, preoperative alignment, age, gender, and soft-tissue releases. Results: Preoperative flexion was the strongest predictor of the postoperative flexion regardless of preoperative alignment. Other factors that were significantly related to reduced flexion were intraoperative flexion (p < 0.0001), gender (p < 0.0001), preoperative tibiofemoral alignment (p = 0.0005), age (p < 0.0001), and posterior capsular release (p < 0.0001). The removal of posterior osteophytes was related to the greatest increase in postoperative flexion in the group of patients with a varus tibiofemoral alignment preoperatively. Conclusions: The principal predictive factor of the postoperative range of motion was the preoperative range of motion. Removal of posterior osteophytes and release of the deep medial collateral ligament, the semimembranosus tendon, and the pes anserinus tendon in patients with large preoperative varus alignment and the attainment of a good intraoperative range of motion improved the likelihood that a good postoperative range of motion would be achieved. Level of Evidence: Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.

Simultaneous bilateral, staged bilateral, and unilateral total knee arthroplasty. A survival analysis.

BACKGROUND The rates of perioperative morbidity and mortality are areas of concern associated with simultaneous bilateral total knee replacement. The purpose of this paper was to compare the rates of morbidity and mortality and the clinical outcome in large groups of consecutive patients undergoing simultaneous bilateral total knee replacement, unilateral total knee replacement, or staged bilateral total knee replacement. METHODS A total of 6200 total knee replacements, performed in 3998 patients between 1983 and 2000, consisted of 2050 simultaneous bilateral, 1796 unilateral, and 152 staged bilateral total knee replacements. A review of each group was conducted to compare the rates of morbidity and mortality, the survival of the prosthesis, and the clinical outcome. Kaplan-Meier survival analyses were performed with failure defined as revision because of aseptic loosening and as patient death. Complications and Knee Society scores were compared throughout the fifteen-year follow-up period (average, 4.3 years of follow-up). RESULTS The unilateral group had significantly lower Knee Society scores than the simultaneous bilateral group (p < 0.0001 up to twelve years, and p = 0.0067 at fifteen years) across all postoperative time-intervals. The percentage of patients who had thrombophlebitis was significantly higher in the simultaneous bilateral group (0.9%) than in the unilateral group (0.3%) (p = 0.0326). No significant differences were found with regard to prosthetic failure, cardiac complications, and the rates of death in the three groups. Ten years postoperatively, the simultaneous bilateral group had a significantly higher rate of patient survival than did the unilateral group (78.6% compared with 72.0%) (p = 0.0062). CONCLUSIONS The significantly higher rate of thrombophlebitis in the simultaneous bilateral group compared with that in the unilateral group may represent a greater risk to those patients. However, we believe that when there are adequate indications for bilateral total knee replacement, simultaneous bilateral arthroplasty is beneficial to patients, with a minimal increase in the risk of death or other complications compared with that associated with unilateral and staged procedures.

A clinical comparison of the anterolateral and posterolateral approaches to the hip.

Patients who had anterolateral and posterolateral approaches in total hip replacement surgery were compared clinically for limp, dislocation, hospital stay, and discharge disposition. The only statistical difference was that the posterior approach had a statistically higher dislocation rate. Although the number of patients with limp was higher in the anterolateral group, the difference was not statistically different.

Manipulation after total knee arthroplasty.

BACKGROUND Following total knee arthroplasty, some patients who fail to achieve >90 degrees of flexion in the early perioperative period may be considered candidates for manipulation of the knee under anesthesia. The purpose of this study was to assess the outcomes of manipulation following total knee arthroplasty. METHODS One hundred and thirteen knees in ninety patients underwent manipulation for postoperative flexion of < or =90 degrees at a mean of ten weeks after surgery. Flexion was measured with a goniometer prior to total knee arthroplasty, at the conclusion of the operative procedure, before manipulation, immediately after manipulation, at six months, and at one, three, and five years postoperatively. RESULTS Eighty-one (90%) of the ninety patients achieved improvement of ultimate knee flexion following manipulation. The average flexion was 102 degrees prior to total knee arthroplasty, 111 degrees following skin closure, and 70 degrees before manipulation. The average improvement in flexion from the measurement made before manipulation to that recorded at the five-year follow-up was 35 degrees (p < 0.0001, paired t test). There was no significant difference in the mean improvement in flexion when patients who had manipulation within twelve weeks postoperatively were compared with those who had manipulation more than twelve weeks postoperatively. Patients who eventually underwent manipulation had significantly lower preoperative Knee Society pain scores (more pain) than those who had not had manipulation (p = 0.0027). CONCLUSIONS Manipulation generally increases ultimate flexion following total knee arthroplasty. Patients with severe preoperative pain are more likely to require manipulation.

The AGC All-Polyethylene Tibial Component: A Ten-Year Clinical Evaluation

Background: While high success rates have been achieved in association with other all-polyethylene tibial components, an alarming number of failures have occurred at our institution in association with the use of an all-polyethylene version of the AGC tibial component. The purpose of the present study was to describe the survival of the AGC all-polyethylene tibial component. Methods: Five hundred and thirty-six AGC all-polyethylene tibial components were implanted in 405 patients and were followed over a ten-year period. The average age of the patients at the time of surgery was 70.3 years, the average weight was 78 kg, and the most common diagnosis was osteoarthritis (prevalence, 92.9%). A clinical and radiographic analysis was performed, Knee Society knee and function scores were determined, and Kaplan-Meier survivorship analysis was conducted. Failure was defined as aseptic loosening as evidenced by progressive radiolucent lines and/or revision due to aseptic loosening or collapse. Results: A high rate of failure was noted in the early postoperative period, with a survival rate of 90.04% (95% confidence interval, 87.35% to 92.72%) after three years. At ten years, the survival rate was 68.11% (95% confidence interval, 57.57% to 78.65%). Fifty-eight (73.4%) of seventy-nine failures occurred in association with loosening or collapse of the bone beneath the medial tibial plateau. Conclusion: While some all-polyethylene tibial designs have been successful, the low success rate among knees treated with the AGC all-polyethylene tibial component suggests that the results associated with all-polyethylene tibial components are design-sensitive. Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

Debate: simultaneous bilateral knee replacements: the outcomes justify its use.

The purpose of this paper is to assess the morbidity, mortality, and clinical outcome of simultaneous bilateral total knee arthroplasty. We reviewed 4100 simultaneous bilateral total knee replacements. The knees were subjected to two Kaplan–Meier survival analyses, with failure equal to revision for aseptic loosening and failure equal to patient death. Complications and Knee Society scores were considered. The average Knee Society knee score was 90 points 3 years postoperatively and 87 points 10 years postoperatively. The complication rates were as follows: deep infection (0.8%), superficial infection (0.3%), cardiac (6 arrhythmia, 5 congestive heart failure, 1 cardiac insufficiency, 3 complete heart block, 2 myocardial infarction and cardiac arrest, and 14 myocardial infarction only) (1.5%), intestinal ileus (0.5%), gastrointestinal ulcer (0.4%), thrombophlebitis (0.9%), cerebrovascular accident (0.3%), and urinary (1 BPH-obstruction, 4 renal failure, 2 transurethral resection of the prostate, 16 urinary tract infection, and 2 urinary retention/incontinence) (1.2%). The 10-year prosthesis survival probability was 98.3%. The 10-year patient survival probability was 78.6%. Twenty-five (1.2%) patients died within the first postoperative year. The patients who died within 1 year postoperatively were older than the rest of the group. Higher age and male gender were factors related to increased mortality. The complication rates and clinical outcomes were similar to unilateral total knee arthroplasty. With regard to death early in the postoperative course, simultaneous bilateral total knee arthroplasty may pose a greater risk to the patient than a unilateral procedure. However, the early deaths may be related to older age at the time of surgery.

Excisional Arthroplasty for Patellar Loosening in Total Knee Arthroplasty

Four thousand two hundred eighty-seven cases of Anatomic Graduated Components total knee replacements with a cemented, single-peg, all-polyethylene patellar component were performed at our institution over the past 15 years. One hundred eighty cases of patellar component loosening were found. Eleven knees (0.3%) in 11 patients required isolated patellar component reoperation. In all cases, the patellar component was excised and not reimplanted. The average follow-up for the 11 patients was 2.2 years. Five had a complete minimum follow-up of 2 years following reoperation. Pain and function were improved. Complications included infection in 3 knees and extensor lag in 1 knee. Because of the complication rate associated with isolated patellar component excision caused by a loose patellar component, we recommend surgical removal of the patellar component only in cases of severe pain and/or prominence of the component.

Total hip arthroplasty with satin finish, tapered stems

Subsidence of femoral hip prostheses with a rough surface has been associated with osteolysis and loosening. However, recent evidence has suggested that smooth-finish tapered stems may not incur these problems. An experimental monobloc satin finish, tapered femoral component was designed to subside within the cement. There were 49 femoral components implanted, and patients averaged a 1.8-mm subsidence at the prosthesis-cement interface with a follow-up of 6.76 years. There were no failures attributable to aseptic loosening at the cement-bone interface. This study supports the use of a satin finish, tapered femoral component in cemented total hip arthroplasty.