Clinical success of prostheses in joint arthroplasty is ultimately determined by survivorship and patient satisfaction. The purpose of this study was to compare (non-inferiority) a new morphometric designed stem for total hip arthroplasty (THA) against an established comparator.

A prospective randomised multi-centre study of 144 primary cementless THA performed by nine experienced orthopaedic surgeons was completed (70 received a fully coated collarless tapered stem and 74 received a morphometric designed proximally coated tapered stem). PROMs and blood serum markers were assessed preoperatively and at intervals up to 2-years postoperatively. In addition, measures of femoral stem fit, fill and subsidence at 2-years post-operatively were measured from radiographs by three observers, with an intra-class correlation coefficient of 0.918. A mixed effects model was employed to compare the two prosthesis over the study period. A p-value <0.05 was considered statistically significant.

Demographics, Dorr types and blood serum markers were similar between groups. Both stems demonstrated a significant improvement in PROMs between the pre- and post-operative measurements, with no difference at any timepoint (p > 0.05). The fully coated tapered collarless femoral stem had a non-significantly higher intra-operative femoral fracture rate (5.8% vs 1.4%, p = 0.24), with all patients treated with cable fixation and partial weight bearing. The mean subsidence at 2-years was 2.5mm +/- 2.3mm for the morphometric stem and 2.4mm +/- 1.8mm for the fully coated tapered collarless femoral stem (p = 0.879). There was one outlier in each group with increased subsidence (fully coated tapered collarless femoral stem 6.9mm, morphometric wedge stem 7.4mm), with both patients reporting thigh pain at 2 years.

When compared with an established stem, the newer designed morphometric wedge stem performed well with comparable radiological and PROM outcomes at 2 year follow up. Continued follow-up is required for long term benchmarking.

Introduction The radial nerve is at risk in arthroscopic elbow surgery and there are reports of significant nerve injury, particularly with arthroscopic synovectomy or arthroscopic capsulectomy for the stiff elbow. This study was aimed to further define the relationship of the radial nerve to the elbow joint.

Methods Magnetic Resonance Imaging studies of 23 elbows with minimal or no pathology were used to measure the distance of the radial nerve from the border of the radial head and the position of the nerve relative to the bony landmarks of the elbow joint.

Results The radial nerve or its branches were found to lie on average 6.6 mm from the border of the radial head (range 3 to 9 mm) and in an arc of 64° antero-lateral to the radial head. At the level of the radial head the nerve was not separated from capsule by muscle in 12 of the 23 elbows.

Conclusions Care should be taken in the insertion of antero-lateral portals in elbow arthroscopy as the position of the radial nerve and its branches is variable. Arthroscopic synovectomy and capsulectomy should be carried out above the level of the radial head where the nerve is protected by brachialis to avoid permanent damage to the radial nerve.