Total knee arthroplasty (TKA) is one of the most successful and beneficial treatments for osteoarthritic knees. We have developed posterior-stabilized (PS) total knee prosthesis for Asian patients, especially Japanese patients, and have used it since November, 2010. The component was designed based on the CT images of osteoarthritic knees, aiming to achieve deep flexion and stability. The purpose of this study was to analyze We analyzed a total of 28 knees implanted with PS TKAs: Fourteen knees with the new PS prosthesis (group A), and the other fourteen knees with a popular PS prosthesis as a control group (group B). Preoperative data of both groups were not significantly difference. Flat-panel radiographic knee images were recorded during five static knee postures including full extension standing, lunge at 90° and maximum flexion, and kneeling at 90° and maximum flexion. The three-dimensional position and orientation of the implant components were determined using model-based shape matching techniques. The results of this shape-matching process have standard errors of approximately 0.5° to 1.0° for rotations and 0.5 to 1.0 mm for translations in the sagittal plane. Unpaired t-tests were used for statistical analysis and probability values less than 0.05 were considered significant.INTRODUCTION
METHODS
Adjusting joint gaps and establishing mediolateral (ML) soft tissue balance are considered essential interventions for better outcomes in total knee arthroplasty (TKA). However, the relationship between intraoperative laxity measurements and weight-bearing knee kinematics has not been well explored. The goal of this study was to establish how intraoperative joint gaps and ML soft tissue balance affect postoperative kinematics in posterior-stabilized (PS)-TKA. We investigated 44 knees with 34 patients who underwent primary PS-TKA. Subjects averaged 71 ± 7 years at the time of surgery, included 8 male and 36 female knees with a preoperative diagnosis of osteoarthritis in 38 knees and rheumatoid arthritis in 6 knees. A single surgeon performed all the surgeries with mini-midvastus approach. After independent bone cutting, soft tissues were released on a case-by-case basis to obtain ML balance. The femoral trial and a tensor were put in place, and the patella was reduced to the original position. A joint distraction force of 40 lb was applied by the tensor, and the central joint gaps and ML tilting angles were measured at 0°, 10°, 30°, 60°, 90°, 120° and 135° flexion (Fig. 1). We defined a “gap difference” as a gap size difference between one gap and another, which represents the gap change between the two knee flexion positions. ML soft tissue balance was assessed by measuring the mean joint gap tilting angle over all flexion angles for each patient. Based on the tilting angle, the 44 knees were classified into three groups: The knees with the mean joint gap tilting of less than −1.0° (13 knees), between −1.0 and 1.0° (14 knees), and over 1.0° (17 knees). At least 1.5 year after surgery, a series of dynamic squat radiographs and 3 static lateral radiographs of straight-leg standing, lunge at maximum flexion, and kneeling at maximum flexion, were taken for each patient. The 3-dimensional position and orientation of the implant components were determined using model-based shape matching techniques (Fig. 2). Correlations between intraoperative measurements and knee kinematics were analyzed. The knee kinematics was also compared among three tilting groups.Introduction:
Methods:
We have investigated the factors which affect the progression of osteoarthritis after rotational acetabular osteotomy (RAO). Between 1984 and 1998, we treated 60 dysplastic hips by RAO. The mean age at surgery was 31.6 years (13 to 51) and the mean period of follow-up was 4.6 years (2 to 9.5). The thickness of the articular cartilage on the weight-bearing area, pre- and postoperative acetabular cover, and the sphericity of the femoral head were used for radiological assessment. The osteoarthritis did not progress in 39 hips. Significant factors which affected the radiological grade included sphericity of the femoral head and the postoperative acetabular cover. The surgical approach and preoperative acetabular cover did not affect the progression of osteoarthritis. Patients were divided into two groups according to the surgical approach used, either conventional (23 hips) or modified (37 hips). Significant factors included the postoperative acetabular cover in the modified approach, and the sphericity of the femoral head in the conventional approach. It is critical that the postoperative cover is sufficient, especially when RAO is carried out using our modified technique.
We reviewed 19 children with 24 congenital club feet at a mean of 11 years after one-stage posteromedial release at the age of five years or older (mean 6.8 years). Thirteen feet had undergone previous surgery. Nineteen feet were functionally excellent or good, three were fair and two had required subtalar arthrodesis. Radiographs showed good alignment of the tarsal bones, although mild adduction or varus deformity remained in several feet. Deformities of the bones were more common in feet which had had previous surgery.
