Corail implants have shown to give good results in elective total hip replacements (THR) and in hemi-arthroplasties. Pre-operative planning to identify the correct size of the Corail implant is vital for good post-operative outcomes. An undersized implant can lead to subsidence. The aim of the study was to review the incidence of subsidence. Post-operative radiographs of trauma patients (n=39) and elective (n=45) patients who had Corail femoral implants were reviewed. The implant-to-canal (I:C) ratio were calculated at the given 50% and 70% levels of the Corail implant. Follow up radiographs were reviewed to identify subsidence. The average age of patients was 80.3 years (range 66–93 years) in hemi-arthroplasties and 61 years (range 18–88) in elective THRs. The implant to canal (I:C) ratio at the 50% and 70% levels in trauma patients were 0.77 (range 0.54 – 0.97) and 0.81 (range 0.59 – 0.94) respectively. In elective patients, the ratios at the 50% and 70% marks were 0.77 (range 0.57 – 0.98) and 0.81 (0.56 – 0.95). One case of subsidence was seen in a collarless implant and I:C ratios at 50% and 70% were 0.57 and 0.56. A larger study is required to determine the reliability of this novel ‘implant:canal’ ratio to predict incidence.
The use of external fixation in the management of long bone fractures has long been recognised. The aim of this study was to compare 3 differing constructs of Hoffman-2 and Hoffman-3 External Fixator systems to assess which potentially withstood the greatest load. Three different constructs (2, 3 and 4-bar) of Hoffman 2 and 3 External Fixation systems were tested. A UHMWPE tube was utilised as a bone substitute to construct a biomechanically reproducible model which could be tested on an MTS testing jig. Each construct was loaded to 3, 5, 8, 12 and 15mm of displacement at the fracture gap. Each construct was cyclically loaded 200 times for each test and repeated 5 times. The results demonstrate that the Hoffman-3 configurations withstood a load of at least twice that of the Hoffman 2 configurations across all displacements. Using a 2-way ANOVA test at all displacements the 2-bar configuration withstood greater load than the 3 bar (P<0.0001). With Hoffman 2 the 2-bar configuration withstood a greater load than the 4 bar diamond configuration. These results demonstrate that Hoffman-3 External Fixation Device has a greater axial loading capacity than its Hoffman-2 predecessor.
We report on the clinical, radiographic and functional outcomes after salvage arthrodesis for complex ankle and hind-foot problems - the Portsmouth experience with the Ilizarov ring fixator. 11 patients underwent ankle and hind-foot (tibio-calcaneal) arthrodeses using an Ilizarov ring fixator between 2006 and 2010. The indications included failed fusion after primary arthrodesis, sepsis complicating internal fixation of fractures, talar avascular necrosis and failed total ankle arthroplasty (TAR). All patients had undergone multiple previous surgeries, which had failed. There were 8 males and 3 females in this group. Average age of the patients was 58 (43 years – 77 years) Mean follow up was 36 months (7 – 60 months). Mean frame time was 24 weeks (15 – 36 weeks). BMP 2 (Inductos) was used in three cases. The procedure was combined with a proximal corticotomy and lengthening in 2 patients who had undergone a talectomy and tibio-calcaneal fusion. There were no major complications apart from minor pin site infections requiring oral antibiotics. There were no deep infections, thromo-embolic issues, CRPS, or functional problems on account of limb shortening. Patients were assessed clinically, radiologically and using functional outcome scores - EQ50 and AOFAS. Solid arthrodesis was achieved in all but one patient who was subsequently revised with a hind-foot nail. All patients were satisfied with their overall improvement in pain and function. We conclude that this is an effective salvage technique for complex ankle and hind-foot problems in patients with impaired healing potential, insufficient bone stock and progressive deformity.
