Introduction: REEF™ is a modular distal locking implant, indicated for use in extensive loosening of femoral stems, peri-prosthetic hip fractures, and tumour surgery requiring distal anchorage to allow resection of the femur proximally. Very little experience with the REEF™ has been reported.

Objective: We report on a single surgeon series of 16 patients who underwent femoral reconstruction using the REEF™ during revision hip arthroplasty (THA).

Methods and Results: This is a retrospective analysis of prospectively collected data on 16 patients (14 females) who underwent revision THA using the REEF™, between 1998 to 2007with a mean follow-up of 16 months (range, 3 to 60).

Indications were peri-prosthetic fractures in 9 cases (Vancouver B1 in one case, B2 in 4 cases and B3 in 4), aseptic loosening with significant bone loss in 3 (Paprosky IIIA in one case, Paprosky IIB in one and Type IV in one), osteolysis (Paprosky IV) secondary to infection in 1, non-union of peri-prosthetic fracture in 2 (Vancouver B2 and B3) and fracture around a spacer in one case.

The mean HHS at 3 months post-operatively was 72 (range, 57 to 76). The median pre-operative/pre-injury University of California, Los Angeles hip rating system (UCLA) was 1. The median UCLA at longest follow-up was 3.5 (range, 1 to 4) with 10 patients having a score greater than 3. Mean time to clinical evidence of implant integration was 4 months (range, 2 to 12). No evidence of subsidence was noted. Four dislocations were seen. No dislocation was seen in the 6 patients who had a Posterior Lip Augmentation Device (PLAD™) inserted at the time of revision THA. One stem fracture occurred requiring revision surgery with a longer REEF™ implant. Two patients died in the immediate post-operative period.

Conclusion: Results of revision THA using the REEF™ implant are encouraging. We recommend the use of the REEF™ with the judicious use of PLAD™ in difficult revision THA.

Resurfacing arthroplasty is advantageous over conventional total hip arthroplasty in that femoral bone stock is preserved. However, there has been controversy over the preservation of acetabular bone stock in resurfacing arthroplasty, with the concern that it may result in excess reaming compared with total hip replacement. This is of concern as the prosthesis is primarily advocated in the young patient, who is likely to face future revision surgery.

We prospectively identified a cohort of 68 patients with primary hip osteoarthritis undergoing conventional total hip arthroplasty. During surgery, the excised femoral head and neck diameter was measured, along with the diameter of the final acetabular reamer used to achieve a bed of bleeding cancellous bone. The measured neck diameter was then used to calculate the minimum possible resurfacing head and cup sizes, with corresponding final reamer sizes that could have been used in each patient without neck notching for both Birmingham Hip Resurfacing (BHR, Smith & Nephew, 3rd Generation) and Articular Surface replacement (ASR, De Puy, 4th Generation). Reaming diameter and volume was compared for all 3 groups.

Mean reaming diameters for the THR, ASR and BHR groups were 51, 52 and 56mm respectively. Mean reaming volumes were 39, 40 and 47cc. There was a statistically significant difference between the THR and BHR groups for both reamed diameter and volume (p< 0.001). There was also a significant difference between the ASR and BHR groups for both reamed diameter and volume (p< 0.001). This difference was more pronounced with larger neck diameters.

Our data shows that the BHR results in more ace-tabular bone loss compared to total hip replacement. An implant with a lower profile acetabular cup and a larger variety of sizes such as the ASR may allow better preservation of acetabular bone stock.