ABSTRACT
BACKGROUND:Cam-type femoroacetabular impingement can impose elevated mechanical loading in the hip, and may eventual y result in hip osteoarthritis, while mechanical mechanism on how this deformity leads to osteoarthritis is stil unclear. OBJECTIVE:To analyze intra-articular mechanical environment of Cam-type femoroacetabular impingement in hip joint using three-dimensional finite element method, and to further understand the features of pathological mechanics. METHODThree-dimensional geometry models of normal and Cam-type femoroacetabular impingement joints were constructed using Mimics and Hypermesh software with the CT data of normal hip joint. These hip models were imported into LS-DYNA analysis system, then dynamic loads and motions for standing up and sitting down were applied to al joint models. Intra-articular cartilage contact pressures and stresses were analyzed in normal hip joint and hip joint with Cam-type femoroacetabular impingement. RESULTS AND CONCLUSION:Based on CT data, models of normal hip joint and hip joint with Cam-type femoroacetabular impingement including articular cartilage for three-dimensional finite element analysis were accurately constructed. Peak contact pressures were 4.43 and 4.59 MPa at the anterosuperior region of the acetabular rim during sitting down and standing up. The peaks of Cam-type femoroacetabular impingement hip joint were 14.96 and 14.86 MPa. Peak pressures and stress concentration were found at the anterosuperior area of acetabular rim. High contact pressure at the acetabular cartilage may be the mechanical mechanism of osteoarthritis induced by Cam-type femoroacetabular impingement.
ABSTRACT
Objective To investigate the efficacy of dual plating internal fixation with olecranon osteotomy approach for the emergency surgery of complex distal humeral fractures (intereondylar and supracondylar fracture).Methods Forty-seven cases of complex distal humeral fractures were treated with emergency surgery from May 2002 to May 2007.The dual plating internal fLxation was implemented with olecranon osteotomy approach in a posteubital slight arc shaped median incision.Early postoperative rehabilitation was necessary.Results The follow-up period differed from 5 to 50 months,averaged 18 months.All fractures healed in 3-6 months after surgery.The Cassebaum scoring system was used for the assessment of cubital joint function,36 cases were excellent,4 cases were good,5 cases were common,and 2 cases were bad.The excellent and good rate was 85.1%.Conclusions For complex distal humeral fractures,dual plating internal fixation emergency surgery with olecranon osteotomy approach ensures the early postoperative rehabilitation of the cubital joint and the maximum possible functional recovery.It shows the efficacy is satisfactory.