Patellar resurfacing versus no resurfacing in two-stage revision of infected total knee arthroplasty.

BACKGROUND: Cartilage debridement and staged reimplantation are the most common treatments for infected total knee arthroplasty (TKA). Very few studies have focused on the management of primarily non-resurfaced patellae in infected TKA. The purpose of this study was to compare the outcomes of patellar resurfacing and non-resurfacing in two-stage revision of infected TKA. METHODS: This study involved a retrospective comparison of the reinfection rate and clinical outcomes of revision TKA patients managed with patellar resurfacing (22 patients, 23 knees) and patients managed without patellar resurfacing (26 patients) at a minimum two-year follow-up. The mean age in the resurfacing group was 69.4years old, and the mean age in the non-resurfacing group was 67.3years old. Three scales were used in the assessment: the Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index, and the Anterior Knee Pain Scale. RESULTS: Three knees had recurrent infections. All infections occurred in patients who had received patellar resurfacing. There were no significant differences between groups in clinical results and on the Anterior Knee Pain Scale. A lack of patellar resurfacing did not increase recurrence of infection and did not result in significant clinical differences compared to patellar resurfacing. CONCLUSIONS: This study indicates that preservation of the original patellar bone is a feasible option for patellar management in revision of septic TKA. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Delayed femoral fracture through a tracker pin site after navigated total knee arthroplasty.

Femoral shaft fractures through a tracker pin site after computer navigated total knee arthroplasty are being increasingly reported. All previously reported fractures have occurred within 3 months of surgery, and thus, any patient with an unexpected thigh pain during the early postoperative period should be carefully monitored for a potential fracture and receive appropriate follow-up care. However, unlike these fractures, we encountered a navigation pin-associated delayed femoral shaft fracture during the late postoperative period (at 12 months postoperatively), which we believe, might be associated with transcortical drilling marks.

Radiographic healing with hemispherical allogeneic femoral head bone grafting for opening-wedge high tibial osteotomy.

PURPOSE: The aim of this study was to investigate the remodeling process after hemispherical femoral head allograft grafting in opening-wedge high tibial osteotomy with a plate and screw. METHODS: The study group included 105 knees in 92 women and 7 knees in 7 men from January 2007 through December 2007. The radiographic bone remodeling process was determined by use of a modification of the radiologic rating system described previously by van Hemert et al. in 4 groups: group A, 7-mm plate correction; group B, 9-mm plate correction; group C, 11-mm plate correction; and group D, 13-mm plate correction. RESULTS: The postoperative femorotibial angle and tibial slope were not significantly changed at latest follow-up in comparison to immediate postoperative status. The mean follow-up period was 25.4 months (range, 18 to 30 months). In all groups radiologic bone healing higher than phase 3 was successfully achieved between 3 and 6 months. The healing process slowed with increasing correction angle. CONCLUSIONS: A hemispherical femoral head allograft is a good alternative osseous graft material when patients are selected appropriately with the following criteria: body mass index lower than 40, no symptomatic osteoarthritis of the patellofemoral joint and lateral compartment, no systemic inflammatory arthritis, no history of fracture or previous open surgery to the lower limb, and no flexion contracture. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Acetabular screw head-induced ceramic acetabular liner fracture in cementless ceramic-on-ceramic total hip arthroplasty.

Ceramic liner fractures are rare after ceramic-on-ceramic THA. This article describes a case of an early ceramic liner fracture caused by impingement with a tilted acetabular screw head 2 months after cementless ceramic-on-ceramic THA. A 59-year-old man underwent primary THA for avascular necrosis of his right femoral head. The implant used was an Osteonics Secur-Fit HA ceramic-on-ceramic bearing system. The metal shell was fixed with 1 cancellous bone screw. During the index procedure, the acetabular screw seemed tilted in the metal shell hole, but the liner was fully seated in the metal shell without difficulty. However, 2 months later he re-presented due to pain and crepitation in the right hip. Radiographs showed that the ceramic acetabular insert had fractured. At revision, ceramic insert had fractured into large and numerous comminuted fragments, and the acetabular screw head was slightly tilted and protruded over the inner surface of the metal shell, which had worn eccentrically. The ceramic inner head and metal shell were visibly intact. Because the metal shell-bone fixation was firm, a new identical design ceramic liner and head were fitted, and no adverse event has occurred since. This case suggests that a complete check of the inside of the shell should be made when using an acetabular screw and ceramic liner. In particular, the screw head must not be tilted or left proud of the inside surface of the shell. Correct acetabular screw direction and seating are essential to avoid detrimental clinical consequences.

Accuracy of implantation during computer-assisted minimally invasive Oxford unicompartmental knee arthroplasty: a comparison with a conventional instrumented technique.

The prognosis of unicompartmental knee arthroplasty (UKA) is strongly associated with the accuracy of the component alignment. To determine the accuracy of navigated UKA during primary minimally invasive Oxford UKA, twenty-nine knees of 29 consecutive patients (Group A) implanted using conventional instrumented UKA were followed by 23 knees of 17 consecutive patients (Group B) implanted by navigation assisted UKA and radiological results regarding alignments of the femorotibial mechanical axis, femur, and tibial component were compared in the two groups. Assessments of mechanical limb alignment revealed statistically significant increases in mechanical limb alignment post-operatively in both groups (p=0.0 for both). In terms of component alignment, Group B had more prostheses implanted in the satisfactory range (> ± 3° from the targeted values) for the femoral and tibial components than Group A. There were no significant differences in the rate of prosthesis implanted within the range of radiographic alignment variations for the coronal implantation of either femoral or tibial components in both groups. (Radiographic alignment variation; coronal orientation of femoral components 90 ± 10°, sagittal orientation of femoral components 90 ± 5°, coronal orientation of tibial components from 10° varus to 5° valgus, sagittal orientation of tibial components from 7° of posterior tibial flexion to 5° of anterior tibial flexion). However, significant increases in the accuracies of sagittal implantation of femoral and tibial components were observed in Group B versus Group A. Our data suggest that navigated implantation improves the accuracy of the radiological implantation of the Oxford UKA prosthesis without increasing complications versus conventional UKA.