Periacetabular osteotomy (PAO) has been established as an effective technique to treat symptomatic hip dysplasia in young patients. Its role in treating borderline dysplasia and acetabular retroversion is evolving.

The aim of this study was to:

Examine the prospectively collected outcomes following a minimally invasive PAO in a large cohort of patients

This is a single-surgeon review of patients operated in a high-volume centre with prospectively collected data between 2013 and 2020, and minimal followup of six months. PAO was performed using a minimally invasive modified Smith Peterson approach. 387 patients were operated during the study period and 369 eligible patients included in the final analysis. Radiographic parameters were assessed by two authors (GS and KB) with interrater reliability for 25 patients of 84–95% (IntraClass Coefficient). Patient reported outcome measures (i-HOT 12, NAHS, UCLA and EQ-5D) were collected prospectively. Case note review was also performed to collate complication data and blood transfusion rates.

Radiological parameters improved significantly after surgery with Lateral centre-edge angle (LCEA) improving by 16.4 degrees and Acetabular index (AI) improved by 15.8 degrees.

Patient reported outcome measures showed significant improvement in post-op NAHS, iHOT and EQ5D at 2 years compared to pre-op scores (NAHS=30.45, iHOT=42, EQ5D=0.32, p=0.01). This significance is maintained over 2 years post procedure (p=0.001). There was no significant difference between the three groups (severe dysplasia, borderline dysplasia and acetabular retroversion).

Clinical outcomes showed an overall complication rate n=31, 8.3% (Major complication rate: n=3, 0.81%). Non-union rate: n=11, 2.96% of which 3 required fixation (0.81%). Hip arthroscopy post PAO: n=7, 1.9%. Conversion to THR: n=4, 1.1%. Blood transfusion requirement: n=46, 12.5%. No patient developed a major neurovascular injury.

In this large single-centre study, patients had radiological and reported outcome improvements following surgery. Overall, there was a low complication rate, providing further evidence of the safety and efficacy of PAO for ameliorating pain and long-lasting results in the management of symptomatic hip dysplasia.

Introduction

The periacetabular osteotomy (PAO) improves hip joint mechanics in patients with symptomatic dysplasia. As a consequence of the multi-planar acetabular re-orientation, the course of the iliopsoas tendon over the hip may be affected, potentially resulting in iliopsoas tendon-related pain. At present, little information regarding the incidence of iliopsoas-related pathology following PAO exists.

We aimed to identify the incidence of iliopsoas-related pain following PAO. Secondarily, we aimed to identify any risk factors associated with this pathology.

The purpose of this study was to determine the complications after Bernese periacetabular osteomy (PAO) performed by one experienced surgeon using a minimally invasive modified Smith-Petersen approach.

Between May 2012 and December 2015, 224 periacetabular osteotomies (PAO) in 201 patients were performed. The perioperative complications were retrospectively reviewed after reviewing clinical notes and radiographs. The mean age was 28.8 years with 179 females and 22 males. The most common diagnosis was acetabular dysplasia with some cases of retroversion. The average lateral centre edge (LCE) angle was 16.5°(−18–45) and mean acetabular index (AI) 16.79° (−3–50).

Postoperatively the mean LCE angle was 33.1°(20–51.3) and mean AI 3.0°

(−13.5–16.6). There were no deep infections, no major nerve or vascular injuries and only one allogenic blood transfusion.

Nine superficial wound infections required oral antibiotics and two wounds needed a surgical debridement. There was one pulmonary embolus and one deep vein thrombosis. Nine (4%) cases underwent a subsequent hip arthroscopy and three (1.3%) PAO's were converted to a total hip arthroplasty after a mean follow-up of 22 months (3–50).

Lateral femoral cutaneous nerve dysaesthesia was noted in 64 (28.6%) PAO's. In 55 (24.5%) an iliopsoas injection of local anaesthetic and steroid for persistent iliopsoas irritation during the recovery phase was given.

The minimally invasive modified Smith-Petersen approach is suitable to perform a Bernese periacetabular osteotomy with a low perioperative complication rate. Persistent pain related to iliopsoas is a not uncommon finding and perhaps under-reported in the literature.

Introduction

Periacetabular osteotomy has been described as an effective way of treating symptomatic hip dysplasia. We describe a new minimally invasive technique using a modification of the Smith Peterson approach.

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.

To quantify the risk posed to the Lateral Femoral Cutaneous Nerve (LFCN) during Total Hip Arthroplasty using the Minimally Invasive Anterior Approach (MIAA), and during placement of the Anterior Portal (AP) in Supine Hip Arthroscopy (SHA). Forty-five hemipelves from thirty-nine cadavers were dissected. The LFCN was identified proximal to the inguinal ligament (IL), and its path in the thigh identified. The positions of the nerve and its branches in relation to the MIAA incision and the site for AP placement were measured using Vernier Callipers. 44% of nerves crossed the incision line used in the MIAA, at an average distance of 47 ± 28mm from the proximal end of the incision. Of those that did not cross the incision line, the average minimum distance between the nerve and incision was 14.4 ± 7.4mm, occurring on average 74.0 ± 37.3mm from the proximal end of the incision. In addition, the AP was placed in the path of the nerve on 38% of occasions. The nerve took an oblique path, and when found not to intersect with the AP portal, was located 5.7 ± 4.5mm from the portal's edge. We found a reduction in risk if the portal is moved medially or laterally by 15mm from its current location. The LFCN is at high risk of injury during both THA using the MIAA and SHA using the AP. Our study emphasises the need for meticulous dissection during these procedures, and thorough explanation of these risk whilst consenting patients. We suggest that relocation of the AP 15mm more laterally or medially will reduce the risk posed to the LFCN