Complications in primary total hip arthroplasty: avoidance and management of dislocations.
ABSTRACT Dislocation in primary total hip arthroplasty is common and problematic and is attributable to several factors, including previous hip surgery, neuromuscular disorders, cerebral dysfunction, psychosis, alcoholism, and female gender. Factors under the control of the surgeon include component orientation and restoration of soft-tissue tension. Prosthetic factors lowering the risk of dislocation include increasing the size of the prosthetic femoral head, keeping femoral neck circumference to a minimum, and optimizing the geometry of the acetabular component. Postoperatively, patients should be expected to comply with standard hip precautions. Treatment is with immediate closed reduction. Multiple dislocations can be treated by advancing the trochanter in the presence of inadequate soft-tissue tension, revision arthroplasty in the presence of malpositioned components, or the use of a constrained cup when intraoperative instability persists. Because the risk of redislocation is much higher than that for first-time dislocation, prevention is critical. An enhanced repair technique can be used to reconstruct the posterior soft-tissue sleeve during the posterior surgical approach. This technique has been successful in lowering the dislocation rate from 4% to 0% in a series of 395 consecutive patients.
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ABSTRACT: The biological effects of transfection of an adeno-associated virus (AAV) vector with bone morphogenetic proteins 4 and 7 (BMP-4/7) fusion gene (AAV-BMP-4/7) were determined in rabbit bone marrow stromal cells (BMSCs). BMP-4 and BMP-7 genes were obtained through one-step reverse transcriptase polymerase chain reaction from human placental cells. The BMP-4/7 fusion gene was then generated through recombination. Rabbit BMSCs were transfected with the recombinant AAV vectors carrying AAV-BMP-4/7 with multiplicity of infection values. Cell growth curves were drawn to evaluate the biological effects of AAV-BMP-4/7 on cell activity. The transfection efficiency was measured using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The ossification of cells was evaluated by observing alkaline phosphatase (ALP) and osteocalcin (OC) activity after transfection for 7 and 14 days. The cells were then transfected with AAV-BMP-4/7 and AAV-enhanced green fluorescent protein. We successfully constructed the recombinant adeno-associated virus with the BMP-4/7 fusion gene. The transfection efficiency of AAV-BMP-4/7 was approximately 72% without significant biological effects on cell activity. Cell ossification was significant after transfection with AAV-BMP-4/7. The 1 x 10(5) vg/cell multiplicity of infection value of transfection efficiency was more than 5 x 10(4) vg/cell (59.38%). Significantly higher ALP and OC activity occurred in the AAV-BMP-4/7 transfection groups than in the AAV-enhanced green fluorescent protein groups (t(ALP) = 896.88, P < 0.001; t(OC) = 543.24, P < 0.01). The AAV-BMP-4/7 fusion gene can highly efficient transfect rabbit BMSCs cultured in vitro and it has significant ossification activity.Genetics and molecular research: GMR 01/2012; 11(3):3105-14. DOI:10.4238/2012.August.31.8 · 0.85 Impact Factor
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ABSTRACT: The influence of dislocation on functional outcomes of primary total hip arthroplasty (THA) are unclear. The purpose of this study was to assess the effect of nonrecurrent dislocations treated with closed reduction following primary THA on post-operative outcome in the short to medium term. Ninety-six patients were enrolled in this retrospective case-control study. There were 32 patients who had a postoperative dislocation. The control group consisted of 64 matched patients who did not dislocate. All patients had a minimum of 1 year follow-up. The two groups were compared using the SF-12, reduced WOMAC and satisfaction questionnaire. There was no statistical difference between the two groups in terms of subjective functional outcomes using the WOMAC or SF-12. However, there was a trend towards better quality of life scores in the control group and they were more satisfied with their surgery compared to the dislocation group.
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ABSTRACT: Purpose of the studyThis study analyzes the incidence on hip dislocation of a posterior minimally invasive approach that combines the suture of the capsular joint and the preservation of the piriformis muscle. Materials and methodsA first prospective series of 98 patients having undergone hip prosthesis by a posterior minimally invasive approach that combines piriformis preservation and capsular closure is analyzed regarding seven criteria: age, weight, duration of surgery, piriformis integrity and quality of capsular closure at the end of the intervention, radiological position of the implants and rate of dislocation at M12. This series is compared to another consecutive series of 98 hip prostheses performed by the same surgeon, via posterior approach, consisting in capsular resection and cutting of the piriformis reinserted on the trochanter. ResultsThe two series were identical regarding patients’ age and weight. The minimally invasive surgery lasted 20min more than the other intervention. In both surgeries, no effect was observed on the radiological position of the implants. The rate of hip dislocation after 12months was significantly improved by the capsular closure combined with piriformis preservation (2.9 vs 0%). DiscussionThe restoration of the capsular plane has been the subject of numerous works. The techniques described had some variations, with a related rate of dislocation <1%. Piriformis preservation participates in the joint coaptation. This muscle is stretched out during the first step of the dislocating movement. ConclusionThe presented series highlights the benefit of combining a capsular flap truly suturable and the preservation of the piriformis muscle aimed at creating a “hammock”, passive and active at the same time, at the upper posterior part of the joint, a strategic area with a high related risk of dislocation.European Journal of Orthopaedic Surgery & Traumatology 07/2008; 18(5):333-337. DOI:10.1007/s00590-008-0295-8 · 0.18 Impact Factor