Eliminating impingement optimizes patellar biomechanics in high knee flexion / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>We investigated the impact of eliminating the impingement between extensor mechanism and tibial insert on patellar tracking and patellar ligament tension in high knee flexion.</p><p><b>METHODS</b>Six cadaveric specimens were tested on an Oxford-type testing rig. The Genesis II knee system was implanted into each specimen knee with the traditional tibial insert and high-flex insert successively. Compared to traditional insert, the high-flex insert was characterized with a chambered anterior post and a chambered anterior lip which eliminates patella-post and patellar ligament-anterior lip impingements. The patella was tracked with an NDI Optotrak Certus system. The patellar ligament tension was measured using a NKB S-type tension transducer.</p><p><b>RESULTS</b>There was a decrease of resultant patellar translation relative to the femur with statistically significant (P<0.05) at 90 degrees to 150 degrees of knee flexion and a decrease of patellar ligament tension with statistical significance (P<0.05) at 100 degrees, 120 degrees, 130 degrees, and 140 degrees of flexion using high-flex insert compared to traditional insert.</p><p><b>CONCLUSIONS</b>Eliminating the impingement between extensor mechanism and implant in high knee flexion altered patellar tracking and reduced patellar ligament tension, which would facilitate high knee flexion.</p>

Clinical results and peri-operative complications of total knee arthroplasty for patients with different ages / 中华外科杂志

<p><b>OBJECTIVE</b>To analyze the clinical results and complications of total knee arthroplasty (TKA) performed for patients with different ages.</p><p><b>METHODS</b>From January 2004 to March 2005,212 patients (300 knees) were followed up, all patients were divided into 6 groups according to the age. All the complications and knee society scores (KSS) were documented and retrieved for analysis.</p><p><b>RESULTS</b>KSS of all groups was significantly improved after TKA. The patients whose age was 70 years or older, and underwent bilateral TKA achieved the best improvement of knee function. The complication rate increased with the patients' age.</p><p><b>CONCLUSIONS</b>TKA predictably alleviates knee pain and restores knee function. Aging itself does not compromise clinical results of TKA. However perioperative complication rate is a little bit higher in aged patient group and simultaneously bilateral TKA patient group.</p>

Reconstruction of the acetabular in the Crowe III dysplastic hip / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the method and the outcome of the acetabular reconstruction in the Crowe III dysplastic hip.</p><p><b>METHODS</b>From January 2001 to June 2007, 43 cases (54 hips) were diagnosed osteoarthritis secondary to Crowe III dysplastic hip. Total hip arthroplasty was performed in all cases. The Harris score was 39 pre-operation. The method of the acetabular reconstruction included acetabular deepening (group A), medial-wall osteotomy (group B), femoral head bone grafting (group C). Radiography data and Harris score were taken to evaluate the clinical outcome.</p><p><b>RESULTS</b>The method of the acetabular reconstruction included acetabular deepening in 27 cases (34 hips), medial-wall osteotomy in 12 cases (15 hips), femoral head bone grafting in 4 cases (5 hips). Forty cases were followed up by the mean time of 29 months. The bone union time of the osteotomy and bone grafting were 4 - 5 months postoperation. In the three groups the obliquity angle of the cup were (41.0 +/- 7.5) degrees , (46.0 +/- 7.7) degrees , (39.0 +/- 11.0) degrees ; the anteversion angle of the cup were (10.0 +/- 2.8) degrees , (9.0 +/- 2.5) degrees , (4.0 +/- 1.9) degrees ; the rotation center of the hip was shift superiorly (8.4 +/- 3.6) mm, (7.3 +/- 2.6) mm, (1.2 +/- 0.5) mm; the rotation center of the hip were shift internally (7.0 +/- 1.5) mm, (9.9 +/- 1.7) mm, (-2.7 +/- 1.2) mm, and the Harris score were 89, 91, 86 at the follow up. The complication included deep venous thrombosis in 2 cases, pulmonary embolism in 2 cases, sciatic nerve palsy in 4 cases.</p><p><b>CONCLUSION</b>Acetabular deepening, medial-wall osteotomy, femoral head bone grafting can be used in reconstruction of the acetabular in the Crowe III dysplastic hip.</p>