Hip squeaking: a 10-year follow-up study.

The aim of the study was to analyze the incidence of squeaking with ceramic-on-ceramic total hip arthroplasty (THA) after 10 years of follow-up and the potential complications that could occur related to this phenomenon. One hundred THAs implanted between November 1999 and December 2000 were evaluated. Incidence of squeaking was investigated clinically with a questionnaire. Implant positioning was analyzed on x-rays and computer tomography. Of the 100 THAs, 5 patients presented with squeaking. All of them were active, sporty, and heavy men. Functional scores were comparable with nonsqueaking patients. There was no malpositioning on the x-ray analysis, no wear, and no loosening. We could not demonstrate any relation between squeaking and ceramic fracture. Squeaking noise appeared at a mean of 66 months postsurgery. It appears to be an isolated phenomenon without any consequences at 10-year follow-up.

Nine years follow-up of 100 ceramic-on-ceramic total hip arthroplasty.

The aim of this study was to evaluate the first 100 cementless ceramic-on-ceramic total hip arthroplasty (THA) performed at our institution with more than nine years of follow-up. Clinical evaluation was performed using Harris hip score. Radiological evaluation was performed by two surgeons. Four patients were lost to follow-up. Harris hip score significantly improved at latest follow-up. Radiological analysis showed calcar osteolysis for 75 patients and one cup loosening. One patient required a revision five years postoperatively for cup loosening. Based on these results and the routine use of a navigation system to optimise positioning of the implants, we advocate the use of uncemented hydroxyapatite coated ceramic-on-ceramic THA in young and active patients in our current practice.

The 2009 Frank Stinchfield Award: "Hip squeaking": a biomechanical study of ceramic-on-ceramic bearing surfaces.

We designed and implemented an in vitro bench test to simulate and identify potential biomechanical causes for hip squeaking with alumina ceramic-on-ceramic bearing surfaces. All bearings were third-generation alumina ceramic with a 32-mm head coupled with a 56-mm acetabular component with a 32-mm ceramic insert. Conditions for testing were normal gait, high load, stripe wear, stripe wear in extreme load, metal transfer, edge wear with extreme load, and microfracture. Each condition was tested two times in dry conditions and two times in a lubricated condition with 25% bovine serum. Squeaking was reproduced in all dry conditions. It occurred quickly with high load, stripe wear, or metal transfer. Once squeaking occurred, it did not stop. Squeaking disappeared for all conditions when a small amount of lubricant was introduced. In lubricated conditions, squeaking was only reproduced for the material transfer condition. Our observations suggest squeaking is a problem of ceramic-ceramic lubrication and that this noise occurs when the film fluid between two surfaces is disrupted. Material (metal) transfer was the only condition that led to squeaking in a lubricated situation.

Use of a dual mobility socket to manage total hip arthroplasty instability.

UNLABELLED: Unconstrained tripolar hip implants provide an additional bearing using a mobile polyethylene component between the prosthetic head and the outer metal shell. Such a design increases the effective head diameter and therefore is an attractive option in challenging situations of unstable total hip arthroplasties. We report our experience with 54 patients treated using this dual mobility implant in such situations. We ascertained its ability to restore and maintain stability, and examined component loosening and component failure. At a minimum followup of 2.2 years (mean, 4 years; range, 2.2-6.8 years), one hip had redislocated 2 months postoperatively and was managed successfully without reoperation by closed reduction with no additional dislocation. Two patients required revision of the implant because of dislocation at the inner bearing. Technical errors were responsible for these failures. Three patients had reoperations for deep infections. The postoperative radiographs at latest followup showed very satisfactory osseointegration of the acetabular component because no radiolucent line or osteolysis was reported. Use of this unconstrained tripolar design was successful in restoring and maintaining hip stability. We observed encouraging results at short-term followup regarding potential for loosening or mechanical failures. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Inflammatory laboratory markers in periprosthetic hip fractures.

The purpose of this study was to determine the prevalence of increased inflammatory laboratory markers in patients with periprosthetic fractures. We also studied the likelihood of the elevation of these values in predicting deep prosthetic joint infection. From 2000 to 2006, 204 patients with periprosthetic hip fractures were treated at our institution. Patients had white blood cell, erythrocyte sedimentation rate, and C-reactive protein obtained on initial evaluation; these were then compared with subsequent hip aspiration, surgical pathology, and deep cultures obtained at the time of revision surgery. A true infection was diagnosed in 11.6%. White blood cell count was increased in 16.2%, erythrocyte sedimentation rate increased in 33.3%, and C-reactive protein increased in 50.5%. The positive elaborate predictive value for these markers for infection was poor (18%, 21%, and 29%, respectively). These findings suggest that increased inflammatory laboratory values in patients with periprosthetic fracture are not good indicators for deep periprosthetic infection and do not necessarily warrant additional evaluations before definitive surgical treatment.

Variability in hip range of motion on clinical examination.

The goal of this study was to determine the interobserver and intraobserver reliability of physical examination in determining hip range of motion. Twenty normal hips, 21 hips with osteoarthritis, and 21 hips of patients more than 12 months after a total hip arthroplasty were examined for visual passive range of motion. These 62 hips were examined by 2 experienced surgeons and by 3 trainees. The 2 experienced examiners repeated their clinical examinations in 19 patients to determine the intraobserver reliability. Intraclass correlation coefficients (ICCs) indicated moderate interobserver agreement in estimates of clinical hip motion (ICC for hip flexion, 0.56 +/- 0.12; for hip abduction, 0.48 +/- 0.13). Intraclass correlation coefficients also suggest only moderate intraobserver reliability in measurements of hip motion (ICC for hip flexion, 0.62 +/- 0.14; hip abduction, 0.44 +/- 0.20). More reliable and accurate methods are needed to measure clinical hip motion before and after total hip arthroplasty.

Unconstrained tripolar implants for primary total hip arthroplasty in patients at risk for dislocation.

We performed a retrospective study on 167 primary total hip arthroplasty (THA) procedures in 163 patients at high risk for instability to assess the reliability of unconstrained tripolar implants (press-fit outer metal shell articulating a bipolar polyethylene component) in preventing dislocations. Eighty-four percent of the patients had at least 2 risk factors for dislocation. The mean follow-up length was 40.2 months. No dislocation was observed. Harris hip scores improved significantly. Six hips were revised, and no aseptic loosening of the cup was observed. The tripolar implant was extremely successful in achieving stability. However, because of the current lack of data documenting polyethylene wear at additional bearing, the routine use of tripolar implants in primary THA is discouraged and should be considered at the present time only for selected patients at high risk for dislocation and with limited activities.