Faculty Bibliography

Partial knee arthroplasty has enjoyed renewed interest during the past decade. It is helpful to be familiar with the classic and current indications, contraindications, and technical aspects of partial knee arthroplasty, including patellofemoral, medial unicompartmental, and lateral unicompartmental knee arthroplasty. Various implant choices for partial knee arthroplasty can be compared and evaluated based on patient characteristics, design qualities, and reported outcomes. It is also helpful to review the indications and techniques for performing medial or lateral unicompartmental knee arthroplasty in combination with arthroscopically assisted reconstruction of the anterior cruciate ligament.

BACKGROUND: The hemoglobin threshold at which postoperative red-cell transfusion is warranted is controversial. We conducted a randomized trial to determine whether a higher threshold for blood transfusion would improve recovery in patients who had undergone surgery for hip fracture. METHODS: We enrolled 2016 patients who were 50 years of age or older, who had either a history of or risk factors for cardiovascular disease, and whose hemoglobin level was below 10 g per deciliter after hip-fracture surgery. We randomly assigned patients to a liberal transfusion strategy (a hemoglobin threshold of 10 g per deciliter) or a restrictive transfusion strategy (symptoms of anemia or at physician discretion for a hemoglobin level of <8 g per deciliter). The primary outcome was death or an inability to walk across a room without human assistance on 60-day follow-up. RESULTS: A median of 2 units of red cells were transfused in the liberal-strategy group and none in the restrictive-strategy group. The rates of the primary outcome were 35.2% in the liberal-strategy group and 34.7% in the restrictive-strategy group (odds ratio in the liberal-strategy group, 1.01; 95% confidence interval [CI], 0.84 to 1.22), for an absolute risk difference of 0.5 percentage points (95% CI, -3.7 to 4.7). The rates of in-hospital acute coronary syndrome or death were 4.3% and 5.2%, respectively (absolute risk difference, -0.9%; 99% CI, -3.3 to 1.6), and rates of death on 60-day follow-up were 7.6% and 6.6%, respectively (absolute risk difference, 1.0%; 99% CI, -1.9 to 4.0). The rates of other complications were similar in the two groups. CONCLUSIONS: A liberal transfusion strategy, as compared with a restrictive strategy, did not reduce rates of death or inability to walk independently on 60-day follow-up or reduce in-hospital morbidity in elderly patients at high cardiovascular risk. (Funded by the National Heart, Lung, and Blood Institute; FOCUS ClinicalTrials.gov number, NCT00071032.).

Recently, implant companies have sought to target a more active segment of the population with high-flex implants. Our aim was to compare a successful medial UKA implant with its newer high-flex version. Sixty-one patients (nonflex, 33; high-flex [HF], 28) were prospectively followed after medial UKA with a minimum of 2-year follow-up. Patients were evaluated using Short Form 12, Western Ontario and McMaster Osteoarthritis (WOMAC), Knee Society Scores, and range of motion (ROM). The HF group exhibited significantly higher WOMAC Physical Function scores at 3-month follow-up and higher WOMAC Pain and SF-12 Mental Component scores at 2-year follow-up; all other comparisons were not statistically different, including ROM. The HF cohort had significantly higher improvements in Knee Society Function and Knee score at 1- and 2-year follow-up, respectively; all other comparisons yielded no significant differences in mean improvement from baseline, including ROM or survivorship.

This prospective cohort study compares functional outcomes of bicompartmental knee arthroplasty (BKA) and total knee arthroplasty (TKA) in patients with osteoarthritis (OA) of the patellofemoral and medial compartments. Eligibility criteria included bicompartmental OA with less than grade 2 OA in the lateral compartment and intact cruciate ligaments. Fifty-six patients met eligibility criteria (21 BKA, 33 TKA). Enrolled participants completed Short-Form 12 and Western Ontario and McMaster Universities Osteoarthritis Index assessments at baseline and postoperatively at 3 months, 1 year, and 2 years. In the early postoperative period, the BKA cohort had significantly less pain (P = .020) and better physical function (P = .015). These trends did not continue past 3 months. When adjusting for age, sex, body mass index, and preoperative status, only 3-month Western Ontario and McMaster Universities Osteoarthritis Index stiffness scores significantly differed between cohorts (P = .048). Despite less early stiffness in the BKA cohort, a significantly higher BKA complication rate (P = .045) has led us to recommend TKA for patients with this pattern of OA.

The purposes of this study were to evaluate the accuracy and reliability of preoperative templating on conventional radiographs (CRs) for metal-on-metal hip resurfacing and to determine the factors affecting the accuracy. Four observers templated 80 CRs on 2 separate occasions in a blinded fashion. Eight independent variables were evaluated to investigate their effect on the accuracy of templating. The overall accuracy of templating within one size of the actual component was 80.6% for the femoral component and 98.5% for the acetabular component. Overall, the intraobserver and interobserver reliability was fair to substantial (kappa = 0.22-0.61). Using multiple regression analysis, surgical time was the only factor that affected the accuracy of predicting the size of the acetabular component (P = .019). We conclude that CR templating for metal-on-metal hip resurfacing is a useful method for preoperative planning of the sizes of the respective implants and that surgeon experience does play a significant role in the accuracy of predicting component size during templating.

Total knee arthroplasty (TKA) is typically an extremely successful method of restoring pain-free function and providing good long-term outcomes for patients with end-stage knee disease. However, outcomes are less predictable in persons with Parkinson disease. The limited literature available and our experience lead us to conclude that complication rates in the perioperative and postoperative periods with TKA are comparatively high in persons with Parkinson disease. In addition, a good functional outcome is less certain than in the general population. For persons with Parkinson disease who require TKA, we propose an integrative, collaborative approach to avoid complications and optimize outcomes.

The purpose of this study was to investigate factors affecting the short-term outcome of primary total hip arthroplasty (THA) and develop a multivariate regression equation to predict the short-term outcome of primary THA. Prospectively collected data for 101 primary THAs performed at a single institution were used in this study. Twelve independent variables were analyzed via correlation and multivariate regression analyses. Correlation analyses showed that three variables significantly influenced Western Ontario and McMaster Universities Osteoarthritis (WOMAC) physical function (PF) score at minimum follow-up of 1 year: preoperative WOMAC PF score (P < .0001), sex (GN, P = .0159), and the presence of preoperative comorbidities (CMB, P = .0246). Multivariate regression analysis yielded the following equation: Outcome = PF0.45 - GN9 + CMB8 + 62, which can be used to predict the general short-term outcome of primary THA.

The purpose of this study was to evaluate the stiffness of 3 different constructs for the fixation of comminuted Vancouver B1 periprosthetic femoral shaft fractures: a single lateral locking plate, a single lateral locking plate plus an anterior strut allograft, and a lateral locking plate plus an anterior locking plate. The axial stiffness, lateral bending stiffness, and torsional stiffness of 10 synthetic periprosthetic femur fracture models were tested. Differences in stiffness between constructs were determined with a 1-way repeated-measures analysis of variance. Fixation technique was found to have a significant effect for all loading modalities (P < .0001). A lateral locked plate plus an anterior locked plate was significantly stiffer than the allograft that in turn was significantly stiffer than the single plate (P < .0001).

From April 2006 to May 2007, 261 patients undergoing primary unilateral total hip arthroplasty or total knee arthroplasty were offered voluntary participation in a one-on-one preoperative educational program. Length of stay (LOS) and inpatient data were monitored and recorded, prospectively. Education participants enjoyed a significantly shorter LOS than nonparticipants for both total hip arthroplasty (3.1 +/- 0.8 days vs 3.9 +/- 1.4 days; P = .0001) and total knee arthroplasty (3.1 +/- 0.9 days vs 4.1 +/- 1.9 days; P = .001).

A tip-apex distance (TAD) of greater than 25 mm has been shown to be an accurate predictor of lag screw cut-out when sliding hip screws (SHS) are used to treat peritrochanteric (PT) hip fractures. The purpose of this study was to determine which factors, including TAD, correlated with successful clinical outcomes of PT hip fractures surgically treated with intramedullary (IM) devices. A total of 192 patients were included in this retrospective study. The TAD values of this cohort were radiographically analysed at a mean follow-up of 13 months. This was correlated with limited functional status and the rate of revision for implant failure or inability to achieve fracture union. Only 82 patients had adequate follow-up to fracture union or definitive failure. There were 46 intertrochanteric (IT) hip fractures and 36 subtrochanteric (ST) fractures. Overall, seven patients (8.5%) went on to experience lag screw cut-out. The average TAD of the patients who did not cut-out was 18 mm, compared to 38 mm for those who did (p = 0.012). All patients who cut-out had IT fractures (p = 0.017). The percentage of cut-outs correlated directly to both the severity of IT fractures and the TAD. Using a cutoff of 25 mm there was a statistically significant difference in the incidence of lag screw cut-out (p < 0.001). As in sliding hip screws, surgeons should strive for a TAD less than 25 mm when using IM devices in the treatment of PT hip fractures to help avoid lag screw cut-out.