Risk Factors for Femoral Fracture after Canine Press-Fit Cementless Total Hip Arthroplasty
ABSTRACT To evaluate risk factors for femoral fracture after porous-coated cementless total hip arthroplasty (THA).
Dogs (n=74) that had cementless THA (n=84).
Medical records of dogs from 2 referral hospitals were reviewed for occurrence of postoperative femoral fracture. Patient and operative (age, breed, sex, weight, and canal flare index [CFI], indication for arthroplasty, intraoperative fissure, cerclage usage, and implant sizes) factors were analyzed. Assessment of implant positioning and canal fill was performed on immediate postoperative radiographs. Femoral fractures (n=11) were evaluated and compared with 73 cases without fracture that met the inclusion criteria.
Mean (+/-SEM) age was 7.30+/-0.69 years for dogs with, and 4.77+/-0.37 years for dogs without femoral fracture. Age was positively associated with fracture (P=.022). Mean (+/-SEM) CFI was 1.80+/-0.09 for dogs with, and 1.98+/-0.04 for dogs without fracture. CFI was negatively associated with fracture (P=.045). Body weight, intraoperative fissure, cerclage use, implant size, position, and canal fill did not influence the occurrence of femoral fracture.
Older dogs and dogs with lower CFI may be at increased risk for femoral fracture after porous-coated cementless THA.
Risk factors exist for femoral fracture after cementless THA using porous-coated implants, and should be critically evaluated during the patient selection. These risks should be weighed against the benefits of the system, and measures to minimize femoral fracture in at-risk patients studied.
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ABSTRACT: Objective: To determine the incidence and potential risk factors of femoral implant loosening in the canine Helica® total hip replacement (THR) system. Method: Sixteen dogs with a Helica THR were included. Medical records were reviewed for signalment and size of implants. Stem angle, stem collar to lateral cortex distance, tip to cortex distance, stem collar to lateral cortex distance at a stem angle of 150°, lever arm distance, and the distance on the diaphysis measurements were calculated from the one year postoperative radiographs. Three ratios were determined from these measurements to take into account the size of the femur in relation to the size of the implant. Femoral implant loosening was identified by radiographic and clinical signs, and confirmed at the time of surgical explantation. Differences in the successful and femoral stem failure groups were compared using either a students t-test or a Mann Whitney test. Significance was set at p <0.003. Results: Six of the 16 dogs had loosening of the femoral prostheses within one year post-implantation. One dog had evidence of a septic cause for loosening. No significant risk factors could be identified in this group of dogs with Helica stem loosening. Clinical significance: Helica femoral stem loosening was a common complication within one year post-implantation in this group of dogs. No risk factors were identified to potentially decrease the incidence of loosening. Therefore, due to this unacceptably high complication rate, the authors do not recommend this model of the Helica THR.Veterinary and Comparative Orthopaedics and Traumatology 11/2014; 28(1). DOI:10.3415/VCOT-14-02-0027 · 1.03 Impact Factor
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ABSTRACT: To date it is unclear whether cementless total hip replacement (THR) in dogs is of clinical advantage in comparison to cemented THR with regard to lameness improvement. Thus the aim of this study was to compare objectively the development of the gait pattern after cemented and cementless THR in dogs. For this purpose, 18 adult dogs with hip dysplasia underwent computer-based gait analysis on an instrumented treadmill prior to unilateral THR and then again ten days, four weeks and four months after surgery. Analysed kinetic parameters were symmetry indices (SI) of vertical ground reaction forces (GRF), which included peak vertical forces (PFz), mean vertical forces (MFz), vertical impulse (IFz), and vertical ground reaction forces of the arthroplasty limbs only. Analysed kinematic parameters were range-of-motion and the flexion and extension angles of hip, stifle and hock joints. The symmetry indice for PVF, MFz and IFz decreased to a value less than six in both THR groups four months after surgery, which is defined as not lame. Improvement in lameness of the arthroplasty limbs during the examination period of four months was not significantly different between the cemented and cementless groups. The results suggest that within a short-term observation period of four months after surgery, neither cementless nor cemented THR have a greater advantage with regard to lameness improvement. Additional studies with larger pools of subjects and longer time periods for follow-up examinations are necessary to verify these findings.Veterinary and Comparative Orthopaedics and Traumatology 07/2012; 25(5):375-84. DOI:10.3415/VCOT-10-02-0026 · 1.03 Impact Factor