Distal Femoral Replacement for Fractures Allows for Early Mobilization with Low Complication Rates: A Multicenter Review.

Periprosthetic fractures around a total knee arthroplasty (TKA), comminuted and intra-articular femur fractures, or fracture nonunions in osteoporotic bone represent technically challenging problems. This is particularly true when the fracture involves a loose femoral component or the pattern results in suboptimal fixation potential. These clinical indications often arise in an older and comorbid patient population in whom a principal goal of treatment includes allowing for early mobilization. Limited data indicate that arthroplasty via distal femoral replacement (DFR) is a reasonable alternative to open reduction and internal fixation, allowing for early ambulation with low complication rates. We performed a retrospective review of trauma and arthroplasty surgeries at three tertiary referral institutions. Adult patients treated for the above with a DFR were included. Patients with active infection, open and/or high-energy injuries and revisions unrelated to fracture were excluded. Patient demographics, treatment details, and outcomes were assessed. Between 2002 and 2017, 90 DFR's were performed for the above indications with a mean follow-up of 24 months. Postoperatively, 80 patients (88%) were allowed to weight bear as tolerated, and at final follow-up, 9 patients (10%) remained dependent on a wheelchair. The average arc of motion at final follow-up was 95 degrees. There were seven (8%) implant-related complications requiring secondary surgeries: two infections, one with associated component loosening; one fracture of the hinge mechanism and one femoral component failure in conjunction with a patellofemoral dislocation (both requiring revision); one case of patellofemoral arthrosis in a patient with an unresurfaced patella; one periprosthetic fracture with associated wound dehiscence; and one case of arthrofibrosis. In each of these cases, only modular components of the DFR were exchanged. All nonmodular components cemented into the femur or tibia were retained. DFR provides a viable reconstruction option in the treatment of acute distal femur fractures, periprosthetic femur fractures, and fracture nonunions. We noted that in an elderly patient population with high comorbidities, the complication and secondary surgery rates remained relatively low, while allowing for immediate weight bearing.

Technical Errors May Affect Accuracy of Torque Limiter in Locking Plate Osteosynthesis.

In locking plate osteosynthesis, proper surgical technique is crucial in reducing potential pitfalls, and use of a torque limiter makes it possible to control insertion torque. We conducted a study of the ways in which different techniques can alter the accuracy of torque limiters. We tested 22 torque limiters (1.5 Nm) for accuracy using hand and power tools under different rotational scenarios: hand power at low and high velocity and drill power at low and high velocity. We recorded the maximum torque reached after each torque-limiting event. Use of torque limiters under hand power at low velocity and high velocity resulted in significantly (P < .0001) different mean (SD) measurements: 1.49 (0.15) Nm and 3.73 (0.79) Nm. Use under drill power at controlled low velocity and at high velocity also resulted in significantly (P < .0001) different mean (SD) measurements: 1.47 (0.14) Nm and 5.37 (0.90) Nm. Maximum single measurement obtained was 9.0 Nm using drill power at high velocity. Locking screw insertion with improper technique may result in higher than expected torque and subsequent complications. For torque limiters, the most reliable technique involves hand power at slow velocity or drill power with careful control of insertion speed until 1 torque-limiting event occurs.

Long-Term Results of Total Hip Arthroplasty with 28-Millimeter Cobalt-Chromium Femoral Heads on Highly Cross-Linked Polyethylene in Patients 50 Years and Less.

Highly cross-linked polyethylene (HXLPE) is the most commonly used bearing surface in total hip arthroplasty (THA) because of its superior wear properties, but long-term results in young patients are limited. We report on the clinical outcome, radiographic wear patterns and survivorship of 72 patients ≤50 years old who had a 28-millimeter cobalt-chromium femoral head on HXLPE acetabular liner. Mean and median true linear wear rates at average ten-year follow-up were 0.0104 and 0.01 mm per year ± 0.07 mm. Mean and median two-dimensional volumetric wear rates were 12.79 mm(3) and 5.834 mm(3) per year ± 26.1mm(3) as determined by Martell analysis. As a result of the minimal wear profile, there was no evidence of radiographic osteolysis and no wear-related revisions.

Perioperative differences in conventional and computer-assisted surgery in bilateral total knee arthroplasty.

Performing bilateral total knee arthroplasties (bTKAs), sequential or staged, is a topic of debate among surgeons. To our knowledge, no studies have compared computer-assisted surgery (CAS) and conventional (CON) procedures for sequential bTKAs. We retrospectively reviewed 124 (62 CAS, 62 CON) sequential bTKAs. CAS-bTKAs required significantly fewer blood transfusions (P = .001) and had significantly better postoperative day 1 (POD-1) hemoglobin (Hgb) levels (P = .001) and POD-2 Hgb levels (P = .01). Mean total blood transfusion units were 0.9 for the CAS group and 1.7 for the CON group. Postoperative range of motion, tourniquet time, length of stay, number of readmissions, and number of reoperations were not significantly different (P > .05). The statistically significant differences between the groups may have resulted from violation of the femoral intramedullary canal during the CON technique.

Variability in locations of hip neurovascular structures and their proximity to hip arthroscopic portals.

PURPOSE: To measure the distances of pertinent neurovascular structures from bony landmarks used during hip arthroscopy and compare them among different demographic groups. METHODS: The distances from neurovascular structures to bony landmarks often used during hip arthroscopy were measured on magnetic resonance images of the hip in 100 patients. The structures studied include the lateral femoral cutaneous nerve (LFCN), sciatic nerve, femoral nerve, and femoral artery. These distances were then compared across different demographic groups, and statistical analysis was performed. RESULTS: The mean anteroposterior (AP) distance from the tip of the greater trochanter to the sciatic nerve was 10.32 mm (range, 0 to 23.8 mm). At the level of the superior tip of the greater trochanter, the mean distances from the anterior superior iliac spine reference line to the LFCN, femoral nerve, and femoral artery were 6.37 mm (range, -9.8 to 35.9 mm) for medial-lateral, 23.24 mm (range, 3.4 to 67.0 mm) for AP, and 26.34 mm (range, 7.3 to 65.5 mm) for AP, respectively. We found significant differences in distances for the LFCN, femoral nerve, and femoral artery for weight (P = .003, P = .041, and P = .004, respectively) and body mass index (P = .003, P = .010, and P = .003, respectively), as well as for the LFCN between whites and Hispanics (P = .032). There were also significant differences for the femoral nerve vector between African Americans and whites (P = .04), as well as between African Americans and Hispanics (P = .04). CONCLUSIONS: We found the LFCN to be the most at-risk neurovascular structure with hip arthroscopy portal placement. This study also showed that there is wide variability in the locations of pertinent neurovascular structures across different demographic groups, including weight, body mass index, and race or ethnicity. CLINICAL RELEVANCE: Portal placement during hip arthroscopy carries a risk of neurovascular injury, particularly to the LFCN. The clinician should be aware of the variability in structure location with different patient demographic characteristics.