MINIMALLY INVASIVE HIP ARTHROPLASTY: A QUANTITATIVE ASSESSMENT OF STUDY METHODOLGY AND REVIEW OF THE LITERATURE

Abstract

Objectives: Minimally invasive hip arthroplasty (MIHA) has become a trend in last few years. The orthopaedic literature is deficient in well designed scientific studies to support the idea that MIHA provides superior outcomes compared with Total Hip Arthroplasty(THA) performed through standard incisions. We have attempted a comprehensive quantitative review of the published literature to assess the methodology of those studies and reported surgical outcomes.

Methods: We conducted a comprehensive literature search of different online databases. All relevant articles in peer-reviewed journals were retrieved except those not mentioning outcomes, case reports, review of literature and letters to editors. Two independent authors analyzed these articles for year of publication, type of study, patient numbers, surgical method, follow-up, complications and patient satisfaction. Each article was also graded using a validated methodology score; Coleman’s Ten Criteria to assess the quality of study.

Results: 38 studies met our inclusion criteria which contained a total of 6434 hip arthroplasties.78.5% (4031) of these were MIHAs. There was significantly less intra-operative blood loss with MIS technique. However no significant difference was noted between the two groups with respect to operating time, the mean length of hospital stay, pain score, dislocation and revision rates, neurological injury and incidence of peri-operative fracture. In addition the patient characteristics and surgeon experience had a significant effect on outcome. Scores were predominantly low for quality of the studies with patient numbers, follow up time and validated outcome measures being the weakest areas.

Conclusion: Minimally invasive hip arthroplasty is clearly in its infancy and continually evolving with new techniques and instruments being developed to treat a broader range of patients. At the present time there is still a lack of quality evidence to advocate its expansion. The better designed studies in fact suggest that it should perhaps be limited further to recognised expert centres. The complication rates and learning curve may be altered by changes in training and adapting surgical techniques. We emphasize the need for meticulous design in future studies comparing the outcomes of these two procedures.