Do Transcortical Screws in a Locking Plate Construct Improve the Stiffness in the Fixation of Vancouver B1 Periprosthetic Femur Fractures? A Biomechanical Analysis of 2 Different Plating Constructs.

OBJECTIVES: This biomechanical study compared Vancouver B1 periprosthetic femur fractures fixed with either a locking plate and anterior allograft strut construct or an equivalent locking plate with locking attachment plates construct in paired cadaveric specimens. METHODS: After 9 pairs of cadaveric femora were implanted with a cemented primary total hip arthroplasty, an oblique osteotomy was created distal to the cement mantle. Femora underwent fixation with either: (1) a locking plate with anterior strut allograft (locking compression plating (LCP)-Allograft) or (2) a locking plate with 2 locking attachment plates (LAPs) (LCP-LAP). Construct stiffness was compared in nondestructive mechanical testing for 2 modes of compression (20 degrees abduction and 20 degrees flexion), 2 four-point bending directions (anterior-posterior and medial-lateral), and torsion. A final load to failure test evaluated the axial compression required to achieve fracture gap closure or construct yield. Fixation was compared through paired t tests (α = 0.05). RESULTS: The LCP-Allograft construct demonstrated higher stiffness values in compressive abduction (207 ± 57 vs.151 ± 40 N/mm), torsion (1666 ± 445 vs. 1125 ± 160 N mm/degree) and medial-lateral four-point bending (413 ± 135 vs. 167 ± 68 N/mm) compared with the LCP-LAP construct (P < 0.05). No differences were identified between the 2 constructs in compressive flexion, anterior-posterior bending, or the load to failure test (P > 0.05). CONCLUSION: Use of the anterior allograft strut created a stiffer construct compared with the LCP-LAP for the treatment of a Vancouver B1 periprosthetic femur fracture only in loading modes with increased medial-lateral bending. Although these static load results are indicative of the early postoperative environment, further fatigue testing is required to better understand the importance of the reduced medial-lateral stiffness over a longer period.

First perforator vein cement occlusion following total hip arthroplasty.

Cement intravasation of the venous system is a rare complication of total hip arthroplasty. This is a case report of a 54-year-old female who sustained cement occlusion of the first perforator vein of the femur after hybrid total hip arthroplasty. However, she was asymptomatic and attained excellent clinical outcome. Differential diagnoses for the radiographic appearance are discussed as well as possible reasons for this occurrence.

Severe metallosis leading to femoral head perforation.

This article describes a case of severe metallosis in a 67-year-old woman who initially underwent primary total hip arthroplasty with a ceramic-on-ceramic articular bearing. This was subsequently revised to a metal-on-polyethylene articulation due to ceramic liner fracture. She presented with severe hip pain and a pelvic mass. Infective workup was negative. Perforation of the cobalt-chrome femoral head was observed intraoperatively. In addition, signs of extensive metallosis, including embedded ceramic debris from the primary procedure, were observed. To the authors' knowledge, this is the first report of a ceramic fracture that led to cobalt-chrome femoral head perforation after subsequent revision total hip arthroplasty. The patient underwent successful revision surgery with a ceramic-on-ceramic coupling. Ceramic materials are increasingly being used in total hip arthroplasty in younger patients. They have excellent tribological properties. However, they also have a lower elasticity and plasticity, which makes them susceptible to sudden material failure. Ceramic fracture is an uncommon yet problematic complication of total hip arthroplasty. Previous authors have reported the importance of performing thorough synovectomy following ceramic liner fracture. Revision surgery using couplings that have a lower hardness, such as metal-on-polyethylene, are best avoided due to their susceptibility to undergo abrasive wear from remaining ceramic particles. The authors advocate revision with ceramic-on-ceramic couplings after ceramic liner fracture.

The benefit of revision knee arthroplasty for component malrotation after primary total knee replacement.

PURPOSE: Revision surgery for component malrotation in the painful TKA is a relatively novel indication. The purpose of this study was to assess the benefit of revision TKA for component malrotation with regard to the clinical and functional outcomes. METHODS: Our retrospective case-control study included 51 patients who underwent revision surgery for malrotation with mean follow up of 42 months. They were equally matched to patients who had surgery for aseptic loosening. RESULTS: Knee society scores improved from 44/49 to 75/60 (p < 0.001) for the study group and 44/47 to 76/57 (p < 0.001) for the control group. There was no statistical difference between the groups, including for VAS scores, narcotic reduction or patient satisfaction. Our study showed that revision surgery for malrotation is as beneficial as surgery for aseptic loosening with regard to clinical and functional outcome. CONCLUSIONS: We recommend CT in painful TKA to assess component malrotation for which revision TKA is beneficial.