Objective To study the operative methods and therapeutic effects of acetabulum reinforcement ring in the reconstruction of acetabular defects in primary and revisional artificial hip replacement. Methods From November 2000 to July 2005, 14 cases (15 hips) of severe acetabular defects in artificial hip replacement were treated with acetabulum reinforcement ring combined autogenous or allogenic bone transplantation, including 7 males and 8 females aged 34-72 years with an average of 55 years. Among them, 9 cases (9 hips) underwent artificial hip joint revision, which was 3-22 years (average8.9 years) far away from their primary replacement, and 5 cases (6 hi ps) received primary replacement, including 1 case of rheumatoid arthritis of both hips, 1 osteoarthritis caused by acetabular dysplasia, 1 femoral head resection due to debridement of hi p infection, 1 nonunion of acetabulum old fracture with the center dislocation of femoral head and 1 old acetabulum fracture. The disease course was 2-25 years (average 11.6 years). According to the American Academy of Orthopaedic Surgeons (AAOS) classification, the acetabulum defects of 7 hips were categorized into Type II, 6 hips were Type III and 2 hips were Type IV. Harris score was (59.1 ± 15.4) points preoperatively. Results All wounds were healed by first intention. The symptom of sciatic nerve simulation was occurred in 1 case and was rel ieved after taking neuroprotective drug for 5 months. All the cases were followed up for 33-90 months (average 51.3 months). Harris score at the final follow-up was (81.9 ± 10.4) points, indicating there was a significant difference between before and after operation (P lt; 0.01). X-ray film demonstrated that the displacement of acetabulum reinforcement ring and acetabular cup was less than 5 mm, the rotation was less than 5°, and there was no progressive radiolucent zone around acetabulum and screw. Conclusion Acetabulum reinforcement ring is beneficial to reconstruct severe acetabular defects, improve hip joints’ function and provide primary stabil ity for putting acetabular cup into an ideal biomechanical position.
Objective To compare the bone resorption between the proximal fixation of the anatomique benoist giraud（ABG） hip and the distal fixation of the anatomic medullary locking（AML） hip by the medium-term X-ray films, and to evaluate the clinical results of the two prostheses. Methods From January 1992 to December 1996, 298 patients (396 hips) underwent the total hip arthroplasty at Wilson Hospital in Korea. In 125 patients, 176 hips were ABG hips, including 103 avascularnecrosis hips, 57 dysplasia hips, and 16 other diseased hips; In the other 173 patient the remaining 220 hips were AML hips, including 147 avascular necrosis hips, 65 dysplasia hips, and 8 other diseased hips. The A-P X-ray imagings were followed up for 5-12 years averaged 8 years, and were compared with the immediate postoperative X-ray imagings. The bone resorption area was measured and the bone resorption cases were recorded according to the Gruen zone obsesvation. Results During operation, 2 ABG hips and 5 AML hips were cracked at the femoral diaphysis; 3 ABG hips and 1 AML hip were cracked at the metaphysis; 6 ABGhips and 3 AML hips were fractured because of trauma after operation; among them, 2 ABG hips needed the stem revision and the remaining hips underwent the openreduction and the internal fixation. During the follow-up, 9 ABG hips were revised, 7 hips of which developed the aseptic loosening. No AML hip was revised, but 3 AML hips developed the aseptic loosening. The bone resorption pattern in theABG and AML hips was similar. The bone resorption occurred most commonly in theGruen zones 1 and 7, and it extended from the metaphysis to the diaphysis. In the Guren zones 2, 5, 6 and 7, there were more AML hips than ABG hips that developed the bone resorption. The bone resorption area around the AML hip was larger than that around the ABG hip. Conclusion The stress shielding bone resorption usually occurs proximally to the union area of the bone and the prosthesis. The ABG prosthesis is a proximal fixation prosthesis, therefore, the stress shielding bone resorption can be reduced. The bone resorption around the AML prosthesis develops slowly within 10 years after operation. The stress shielding bone resoption may reach the summit within 10 years and it will not develop endlessly, so the prosthesis will be stable for a long time. The probabilityof the bone resorption in the ABG prosthesis is smaller than that in the AMLprosthesis. The bone resorption around the AML prosthesis may develop slowly after 10 years and will not affect the stability of the prosthesis for a long time.
ObjectiveTo explore the cause of prosthesis dislocation after primary artificial hip replacement (AHR) and propose preventive measures. MethodsA total of 221 patients underwent artificial hip replacement from 2000 to 2012, among whom 8 developed dislocation. These cases were retrospectively analyzed to summarize the causes of dislocation and preventive measures were proposed. ResultsAmong 221 cases of hip replacement, 8 suffered from postoperative dislocation. All of them underwent posterolateral-approach total hip arthroplasty. The causes of dislocation included coexisting decreased muscle strength before operation, improper placement of the prosthesis during operation, inappropriate postural changes after operation, improper nursing and health education. Of the 8 dislocation cases, 2 were cured after reoperation and revision, 6 were cured through close reduction under anesthesia, and 7 were followed up for 1-5 years without relapse. ConclusionPreoperative assessment of the patients' soft tissue tension of affected hip and comorbid conditions, selection of proper design of prostheses and the components, removal of tissues possibly causing joint impact, correct placement of artificial prosthesis and components and instructing the patients for the correct movement mode of the affected hip after operation are all crucial for the prevention of postoperative hip dislocation.