Periprosthetic fractures present an increasing workload as more hip arthroplasties are performed. They are often challenging to treat due to poor bone stock and patient frailty. We compare the early clinical and radiological results in 2 centres of 24 consecutive periprosthetic hip fractures in 24 patients, using a cannulated interlocked long stemmed titanium alloy femoral component with or without a hydroxyapatite (HA) coating (Cannulok revision prosthesis).

The mean age at the time of operation was 79 years (range 65 to 92.4 years). The average length of follow up was 1.17 years (range 3 months to 5.3 years). All patients receiving a Cannulok revision stem with a minimum follow up of 3 months were included regardless of their primary aetiology and number of previous surgical procedures. Patients were reviewed and scored using the Merle d’Aubigne and Postal Score, Harris Hip Score and the WOMAC index at latest review. Periprosthetic fractures were classified using the Vancouver classification. At latest radiological review we measured subsidence, new bone formation (including presence of callus), osteolysis and radiolucent lines in all areas of the stem.

Of the 24 fractures, 22 healed. In the 14 who had HA coated implants there was a 50% increase in bone. In the non-HA coated stems there was a 36% increase in bone radiologically. The mean Harris hip score was 74 at the latest post-operative review. The mean WOMAC and MDP scores were 48.7 and 7.7 respectively. The mean pain visual analogue score was 1.6 overall and 0 specifically for mid-thigh pain.

We present encouraging early clinical and radiological results of the Cannulok stem system for treatment of complex periprosthetic fractures. This implant provides early fracture stability and subsequent biological bonding with an improvement in bone mass.