Ceramic-on-ceramic (CoC) bearings in total hip replacements (THRs) have shown low wear volumes under standard gait in hip simulator studies. However, clinical reports have indicated variations in wear rates and formation of stripe-like wear area on the ceramic femoral heads. The aim of this study was to investigate the influence of cup inclination angle and microseparation on the wear of CoC bearings in THRs. The six station Leeds II Physiological Anatomical Joint Simulator was used to investigate the wear of 28 mm diameter alumina matrix composite ceramic bearings (BIOLOX® delta). It was shown that increasing the cup inclination angle from 55° to 65° had no significant effect on the wear rate of BIOLOX® delta CoC under both standard gait and microseparation conditions in this in vitro study. Under standard gait conditions, the mean wear rate for both cup inclination angle conditions was very low at 0.05 mm(3)/million cycles. The introduction of microseparation to the standard gait cycle increased the mean wear rates to 0.13 mm(3)/million cycles for the cup inclination angle of 55° and 0.11 mm(3)/million cycles for that of 65°. The level of increased wear with microseparation was not dependent on cup angle. A stripe of wear on the head also formed, with corresponding superior rim wear on the cup. The wear rates obtained were low compared to the HIPed third generation alumina ceramic (BIOLOX® forte) tested under the same adverse conditions (1.84 mm(3)/million cycles). BIOLOX® delta has shown lower wear than previous ceramic materials used in THR under adverse conditions.
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http://dx.doi.org/10.1002/jbm.b.31708 | DOI Listing |
Arthroplasty
January 2025
Sant'Andrea Hospital, Faculty of Medicine and Psychology, Sapienza University of Rome, 00162, Rome, Italy.
Background: Proper positioning of a total hip arthroplasty (THA) plays a crucial role in the success and long-term survivorship of the implant. Cup positioning within the Lewinnek Safe Zone (LSZ) does not, however, avoid implant dislocation. Thus, the concept of a functional cup position has been introduced.
View Article and Find Full Text PDFBone Jt Open
January 2025
Department of Orthopaedic Surgery, Ehime University Graduate School of Medicine, Toon, Japan.
Aims: Excellent outcomes have been reported following CT-based robotic arm-assisted total hip arthroplasty (rTHA) compared with manual THA; however, its superiority over CT-based navigation THA (nTHA) remains unclear. This study aimed to determine whether a CT-based robotic arm-assisted system helps surgeons perform accurate cup placement, minimizes leg length, and offsets discrepancies more than a CT-based navigation system.
Methods: We studied 60 hips from 54 patients who underwent rTHA between April 2021 and August 2023, and 45 hips from 44 patients who underwent nTHA between January 2020 and March 2021 with the same target cup orientation at the Department of Orthopedic Surgery at Ozu Memorial Hospital, Japan.
J Orthop Surg Res
December 2024
Department of Orthopeadics, the First Medical Centre, Chinese PLA General Hospital, Beijing, China.
Background: This study aimed to report the mid-term functional outcomes of total hip arthroplasty (THA) for the treatment of advanced hip involvement in ankylosing spondylitis (AS) and identify the factors associated with poor hip flexion range of motion (ROM) after THA in patients with AS.
Methods: We retrospectively investigated the mid-term functional outcomes in 313 AS patients (538 hips) who underwent primary THA from 2012 to 2017, with a mean follow-up of 7 years (range, 4-9 years). Postoperative functional outcomes were assessed by hip flexion ROM, Harris hip score (HHS), and the Western Ontario and McMaster Universities Arthritis Index (WOMAC).
Background: Is "eyeballing" enough to determine cup malposition on anteroposterior (AP) pelvis radiographs before revision total hip arthroplasty (rTHA) for instability? We aimed to determine the following: (1) the reliability of eyeballing cup inclination/anteversion on AP pelvis radiographs vs geometrical measurements and (2) whether visual assessments are affected by surgeon experience.
Materials And Methods: Fifteen de-identified standing AP pelvis radiographs obtained before rTHA for instability were evaluated by one orthopedic surgeon who measured inclination/anteversion of the cups (n=15) using a new simplified method based on basic geometry. Subsequently, 4 orthopedic surgeons and 4 fellows (postgraduate year 6) assessed inclination/anteversion by eyeballing.
SICOT J
December 2024
The Hazeley Academy, Emperor Drive, Hazeley, Milton Keynes, MK8 0PT, United Kingdom.
Introduction: Robot-assisted instrumentation during total hip arthroplasty (THA) has the potential to improve acetabular cup positioning. This study aimed to evaluate the precision of robotic-arm-assisted THA (rTHA) and assess whether the system can provide accurate cup positioning comparable to conventional THA (cTHA).
Methods: A single-center prospective cohort study consisting of 151 patients who underwent THA (108 rTHA and 43 cTHA).
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