Abstract
Despite initial enthusiasm for minimally invasive total hip replacements (THR), there has been a marked paucity of level 1 evidence studies assessing it.
100 patients fulfilling the inclusion criteria were randomised in theatre to a standard posterior or muscle-sparing short incision (MIS) approach. A hybrid hip replacement was used routinely. Post-operative management was the same. Follow-up occurred at 2, 6 and 12 weeks. Patients, as well as functional and radiographic assessors were blinded.
50 patients were recruited to each group. There was no difference in demographics Mean incision length was 12.8cm and 19.1cm respectively. There was no statistically significant difference in operation time, post-op functional recovery (ILOA score) or length of stay. Pain (VAS) was similar post-operatively, and at 6 and 12 weeks. There was no significant difference in 10 metre walking speed or 6 minute walking distance at 2, 6 or 12 weeks; nor was there a difference in Oxford hip score, patient satisfaction with surgery (VAS), or SF-12 score at 6 or 12 weeks. Blood loss, fall in haematocrit, transfusion rate and CRP rise were similar. There was no significant difference in cementation of the stem (Barrack) or cup position (Dorr). There was one death from PE in the MIS group and one deep infection in the standard group. There was one dislocation in the standard group. The only statistical difference between the groups was less dependence on walking aids at 2 and 6 weeks in the MIS group; there was no difference at 12 weeks.
MIS surgery is safe, and may allow earlier independent mobility after THR. However, the claims of significantly reduced pain, less morbidity, better function and improved patient satisfaction appear to be unfounded.
Correspondence should be addressed to Mr Peter Howard, Editorial Secretary, BHS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE, England.
