Faculty Bibliography

Simultaneous bilateral knee arthroplasty (SBTKA) in octogenarians is controversial. Our purpose was to review the outcomes of octogenarians undergoing SBTKA. All patients greater than 80 years of age who underwent SBTKA by a single surgeon were retrospectively evaluated. Fifty-six patients with an average age of 82.5 years were identified. Twelve postoperative complications occurred. Three were serious; two non-fatal PEs and one wound debridement. Minor complications included UTI, decubitus ulcer, DVT, confusion, transfusion reaction and ileus. Average postoperative survival was 7.4 years. No deaths occurred within 30 days postoperatively. Simultaneous bilateral total knee arthroplasty can be a safe and effective option for octogenarians. Complications and mortality are not higher for SBTKA compared to UTKA in this population.

Arthrodesis is a widely accepted treatment for failed total knee arthroplasty when further revision is contraindicated. In this study, we retrospectively review the pre-operative characteristics, operation techniques, treatment plans, and eventual outcomes in 42 consecutive patients (43 knees) who underwent knee arthrodesis at a single institution. Femorotibial fusion was achieved in 30 cases (75.0%). No cases of implant failure were recorded. Post-operative complications occurred in 20 cases (46.5%). Repeat arthrodesis was performed in 4 cases, and 2 patients eventually required above-the-knee amputation. Comparing the cases with successful vs. unsuccessful outcomes, there was a significant difference in days until hospital discharge following arthrodesis (P = .026), mean erythrocyte sedimentation rate prior to arthrodesis (P = .012), and the proportion of patients with post-operative wound complications (P = .021).

The kinematics of seven knee specimens were measured from 0 to 120 degrees flexion using an up-and-down crouching machine. Motion was characterized by the positions of the centers of the lateral and medial femoral condyles in the anterior-posterior direction relative to a fixed tibia. A modular unicompartmental knee, trochlea flange, and patella resurfacing (multicompartmental knee [MCK] system) were implanted using a surgeon-interactive robot system that provided accurate surface matching. The MCK was tested, followed by standard cruciate retaining (CR) and posterior stabilized (PS) knees. The motion of the MCK was close to anatomic, especially on the medial side, in contrast to the CR and PS knees that showed abnormal motion features. Such a modular knee system, accurately inserted, has the potential for close to normal function in clinical application.

INTRODUCTION: Catastrophic polyethylene failure is a rare complication of ceramic-on-polyethylene total hip arthroplasty due to the favorable tribological characteristics of ceramic. Failure of the polyethylene liner can be disastrous, increasing periprosthetic osteolysis, metallosis, and risk of dislocation. Complications associated with ceramic-on-polyethylene articulations have been studied extensively, however, only few reports have described its catastrophic wear. We report such a case of complete wear of the acetabular liner in a ceramic-on-polyethylene prosthesis in a 57-year adult male. CASE REPORT: A 57-year adult male with a history of bilateral total hip arthroplasty presented to our institution with bilateral hip pain worst on the right. Range of motion was limited by pain on the right hip at the extremes of motion. Radiographs revealed severe osteolysis, heterotopic ossification, complete wear of the acetabular liner, bony impingement of the femoral greater trochanter on the acetabular rim and superior migration of the femoral head. All findings were confirmed intraoperatively. Revision of the acetabular components was performed, which successfully alleviated the patient's symptoms. CONCLUSION: Failure of the ceramic-on-polyethylene liner in our patient is due to the use of a non-cross linked polyethylene liner, a highly active lifestyle, and poor follow up. Arthroplasty surgeons should be aware of this complication especially in highly active patients with a conventional polyethylene liner and chronic hip pain.

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Our goal was to report a 10-year follow up of linear penetration rates for HCLPE, and to determine whether a difference exists between penetrations measured on pelvis or hip anterior-posterior radiographs. We reviewed 48 total hip arthroplasties where a first-generation HCLPE liner was used. Femoral head penetration was measured on both AP pelvis and hip radiographs. Total wear and wear rate at 10years were 1.26mm and 0.122mm/y, respectively. The rate decreased significantly after the first 2-3years, plateauing at a wear rate of 0.05mm/y for the last 5years. The AP hip total wear and wear rate were 1.38mm and 0.133mm/y respectively, while rates were 1.13mm and 0.109mm/y respectively for the pelvis radiographs (P<.05). We found a significant difference in measurements of linear penetration when comparing AP pelvis vs. hip radiographs with lower rates recorded using an AP pelvis.

Today, patients with human immunodeficiency virus (HIV) live long enough to develop chronic degenerative and HIV-associated joint disease. There is a growing population of patients infected with HIV who are candidates for total hip arthroplasty (THA). A total of 31 HIV-positive, non-hemophilic patients undergoing 41 THAs at our institution between 2000 and 2012 were identified. In-hospital medical complications were reported in 5 of 41 hips, all of which resolved prior to discharge. Deep infection developed in 1 of 41 hips and revision was required in 3 of 41 hips. These results suggest that low rates of complications and revision can be achieved in the HIV-positive, non-hemophilic population. We believe that with careful patient selection, THA may improve the quality of life in the HIV-positive population.

OBJECTIVES: To compare lag-screw sliding characteristics and fixation stability of two cephalomedullary nails (CMN) with different lag-screw designs (solid and telescopic), we conducted a biomechanical study and an analysis of clinical results. METHODS: Six pairs of cadaver femurs with simulated intertrochanteric fractures were randomly assigned to one of two CMN fixations. Femur constructs were statically then cyclically loaded on an MTS machine. Lag-screw sliding and inferior and lateral femoral head displacements were measured, following which failure strength of the construct was determined. Forty-five patients with intertrochanteric fractures treated with these CMN were identified. Medical records and radiographs were reviewed and analyzed using Fisher's exact test and Student's t test to determine lag-screw sliding. RESULTS: No difference was seen with cycling in inferior femoral head displacement between the two screw designs. The solid screw had an average inferior head displacement of 1.75 mm compared with 1.59 mm for the telescoping screw (p = 0.772). The solid lag screws slid an average of 2.79 mm lateral from the nail, whereas the telescoping screws slid an average of 0.27 mm (p = 0.003). In our clinical review, the average lateral sliding of the telescoping screw was 0.5 mm and of the solid screw was 3.7 mm (p < 0.001). Despite differences in lateral sliding, there were no reoperations for prominent or painful hardware in either group. CONCLUSIONS: Both designs are acceptable devices for stabilization of intertrochanteric fractures. Clinical and biomechanical data demonstrate greater lateral sliding in the solid lag-screw group, making for greater potential for lateral-sided hip pain in CMNs with solid lag screws as opposed to telescoping lag screws.