Aim

The aim of this study was to compare a single-incision minimally invasive (MI) posterior approach with a standard posterior approach in a double-blind prospective randomised controlled trial.

We undertook a randomised controlled trial to compare the piriformis-sparing approach with the standard posterior approach used for total hip replacement (THR). We recruited 100 patients awaiting THR and randomly allocated them to either the piriformis-sparing approach or the standard posterior approach. Pre- and post-operative care programmes and rehabilitation regimes were identical for both groups. Observers were blinded to the allocation throughout; patients were blinded until the two-week assessment. Follow-up was at six weeks, three months, one year and two years. In all 11 patients died or were lost to follow-up.

There was no significant difference between groups for any of the functional outcomes. However, for patients in the piriformis-sparing group there was a trend towards a better six-minute walk test at two weeks and greater patient satisfaction at six weeks. The acetabular components were less anteverted (p = 0.005) and had a lower mean inclination angle (p = 0.02) in the piriformis-sparing group. However, in both groups the mean component positions were within Lewinnek’s safe zone. Surgeons perceived the piriformis-sparing approach to be significantly more difficult than the standard approach (p = 0.03), particularly in obese patients.

In conclusion, performing THR through a shorter incision involving sparing piriformis is more difficult and only provides short-term benefits compared with the standard posterior approach.

The aim of this study was to compare a single-incision minimally invasive posterior approach with a standard posterior approach in a double-blind prospective randomised controlled trial.

A pilot study was carried out to assess the efficacy of the minimally invasive (MI) approach. The protocol described in the CONSORT statement was used as a template for the study design. 100 Primary total hip replacements meeting the inclusion criteria were randomised in theatre to either the MI approach (using a small incision with preservation of piriformis and distal aspect of quadratus femoris) or the standard posterior approach. Hips meeting the inclusion criteria were randomised in theatre using sealed identical opaque envelopes. Patients were blinded to allocation and all patients remained in the group they were allocated to. Pre and post-operative care programmes were identical. Patients were scored by a blinded research physiotherapist pre-operatively, at Day 2, 2 weeks, 6 weeks and 3 months post operation. The primary outcome measure was function, assessed using the Oxford hip score, SF-12 questionnaire, Iowa score, 6-minute walk test and the number of walking aids required after 2 and 6 weeks post operatively. Secondary outcomes were complication rates, patient satisfaction, difficulty of the procedure as perceived by the surgeon, soft tissue trauma (CRP and blood loss) and radiographic analysis.

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.

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.

Introduction: With the rising number of primary hip arthroplasties performed each year, patient selection criteria is becoming increasingly pertinent. There is growing concern that patients with a high body mass index (BMI) have worse outcomes following hip replacement surgery. However the evidence base is equivocal.

Our aim is to assess whether BMI has an impact on clinical and radiological outcomes of primary total hip arthroplasties

Methods: This is a prospective study of 92 patients, undergoing primary total hip arthroplasty, recruited from two hospitals. Data was collected by the operating surgical team and independent physiotherapists at the preoperative assessment clinic, intraoperatively and at six weeks post-operative follow up.

BMI was recorded. Patients were divided into 2 groups: those with a BMI less than 30 (considered nonobese) and those 30 or above (obese).

Outcomes assessed included blood loss and requirement blood transfusion, fat thickness, operation duration, complications and surgeon’s perception of the difficulty of operation (scored on a VAS). In addition functional capacity was assessed using the Oxford Hip scores pre and post-operatively. Radiographs were scored independently according to Dorr and Barrack.

Results: Of our 92 patients, 36 were obese and 56 were non-obese. There was no significant difference found in blood loss, blood transfusion requirements, operation duration and complications between the two groups, With regards to the Oxford Hip scores, the obese patients had greater differences between their pre- and post-operative scores but this difference was not significant (p=0.09). We found a significant difference (p=0.003) in surgeons’ perception of the difficulty of operation with VAS scores for obese patients being higher than non-obese patients. Our Dorr and Barrack scores revealed no significant difference in radiological outcome between our two groups.

Conclusion: Our study would suggest that obese patients do not have worse outcomes following primary total hip arthroplasty than non-obese patients.