Modular total hip arthroplasty (MTHA) stems were introduced in order to provide increased intra-operative flexibility for restoring hip biomechanics, improving stability and potentially reducing revision risk. However, the additional interface at the neck-body junction provides another location for corrosion or mechanical failure of the stem. To delineate the mid term revision risk of MTHA stems, we examined data from the Canadian Joint Replacement Registry (CJRR) at the Canadian Institute for Health Information (CIHI). Kinectiv, Profemur and Rejuvenate modular stems were identified from CJRR records submitted between 2004 and 2014. Revision status was determined by examining the discharge abstract database (DAD) also housed by CIHI, which collects information on all revisions, regardless of whether the procedure was submitted to CJRR. A total of 2446 modular stems were identified with a mean follow up of 4.2 years (range 0 to 10). Their usage peaked in 2012 (the first year of mandatory CJRR form submission for BC, ON and MB), and dropped rapidly thereafter. A total of 155 (6.3%) were revised. This consisted of 5/301 Kinectiv (1.7%), 141/2050 ProFemur (6.9%), and 9/96 Rejuvenate (9.4%) stems. As a group, this falls below the National Institute for Clinical Excellence (NICE) guidelines of 95% survival at 10 years. While MTHA stems were introduced to improve outcomes and reduce revision risk, our findings of a 6.3% revision risk at a mean follow up of 4.2 years does not appear to support this.
To evaluate the radiological changes after metal on metal resurfacing arthroplasty. Between December 1998 and August 2004, 166 hips in 150 patients who underwent metal resurfacing arthroplasty and followed up more than 4 years. Their mean age at the time of operation was 37.3 years(range, 15–68 years) and mean period of follow-up was 6.1 years(range, 48–95 months). The cause of arthroplasty included 115 avascular necrosis, 43 osteoarthritis, 7 ankylosing spondylitis, 1 haemophilic arthropathy. All patients had anteroposterior, translateral radiographs of the hip made preoperatively and each follow-up visit, and we analyzed radiographic findings such as radiolucencies or impingement signs around implant, neck narrowing and heterotopic ossification.Purpose
Materials and Methods
