12-year survival analysis of 322 Hintegra total ankle arthroplasties from an independent center.

Background and purpose - Total ankle arthroplasties (TAAs) have larger revision rates than hip and knee implants. We examined the survival rates of our primary TAAs, and what different factors, including the cause of arthritis, affect the success and/or revision rate.Patients and methods - From 2004 to 2016, 322 primary Hintegra TAAs were implanted: the 2nd generation implant from 2004 until mid-2007 and the 3rd generation from late 2007 to 2016. A Cox proportional hazards model evaluated sex, age, primary diagnosis, and implant generation, pre- and postoperative angles and implant position as risk factors for revision.Results - 60 implants (19%) were revised, the majority (n = 34) due to loosening. The 5-year survival rate (95% CI) was 75% (69-82) and the 10-year survival rate was 68% (60-77). There was a reduced risk of revision, per degree of increased postoperative medial distal tibial angle at 0.84 (0.72-0.98) and preoperative talus angle at 0.95 (0.90-1.00), indicating that varus ankles may have a larger revision rate. Generation of implant, sex, primary diagnosis, and most pre- and postoperative radiological angles did not statistically affect revision risk.Interpretation - Our revision rates are slightly above registry rates and well above those of the developer. Most were revised due to loosening; no difference was demonstrated with the 2 generations of implant used. Learning curve and a low threshold for revision could explain the high revision rate.

Can an off-the-rack orthotic stiletto alter pressure and comfort scores in the forefoot, arch and heel?

The study sought to investigate whether an orthotic stiletto could modulate the pressure and comfort under the forefoot, arch and heel that stiletto wearers experience. Twenty-two women participated. We measured the peak pressure and pressure-time integral for orthotic stilettos with built-in metatarsal pad, heel cup and arch support; standard stilettos without inlays; and trainers. Comfort was recorded during 3 × 3 working days. The orthotic stiletto exhibited lower metatarsal head1 (MTH) and MTH2+3 and heel pressures than the standard stiletto (p < .01), and a long second metatarsal increased MTH2+3 pressure (p < .01). The comfort in the forefoot and heel was higher in the orthotic stiletto than in the standard one (p < .01), and comfort in the forefoot was correlated to the pressure-time integral of MTH2+3 (p = .03) and not peak pressure. Off-the-rack orthotic stilettos can notably reduce plantar pressures and improve forefoot and heel comfort during everyday use. Practitioner Summary: Off-the-rack orthotic stilettos with built-in metatarsal pad, arch support and heel caps can lower the pressure under the heel and forefoot in comparison with a standard stiletto and can improve comfort during everyday use. Having a long second metatarsal is a risk factor for increased forefoot pressure.

Similar range of motion and function after resurfacing large-head or standard total hip arthroplasty.

BACKGROUND AND PURPOSE: Large-size hip articulations may improve range of motion (ROM) and function compared to a 28-mm THA, and the low risk of dislocation allows the patients more activity postoperatively. On the other hand, the greater extent of surgery for resurfacing hip arthroplasty (RHA) could impair rehabilitation. We investigated the effect of head size and surgical procedure on postoperative rehabilitation in a randomized clinical trial (RCT). Methods We followed randomized groups of RHAs, large-head THAs and standard THAs at 2 months, 6 months, 1 and 2 years postoperatively, recording clinical rehabilitation parameters. RESULTS: Large articulations increased the mean total range of motion by 13° during the first 6 postoperative months. The increase was not statistically significant and was transient. The 2-year total ROM (SD) for RHA, standard THA, and large-head THA was 221° (35), 232° (36), and 225° (30) respectively, but the differences were not statistically significant. The 3 groups were similar regarding Harris hip score, UCLA activity score, step rate, and sick leave. INTERPRETATION: Head size had no influence on range of motion. The lack of restriction allowed for large articulations did not improve the clinical and patient-perceived outcomes. The more extensive surgical procedure of RHA did not impair the rehabilitation. This project is registered at ClinicalTrials.gov under # NCT01113762.

Reproducibility of range of motion and muscle strength measurements in patients with hip osteoarthritis - an inter-rater study.

BACKGROUND: Assessment of range of motion (ROM) and muscle strength is fundamental in the clinical diagnosis of hip osteoarthritis (OA) but reproducibility of these measurements has mostly involved clinicians from secondary care and has rarely reported agreement parameters. Therefore, the primary objective of the study was to determine the inter-rater reproducibility of ROM and muscle strength measurements. Furthermore, the reliability of the overall assessment of clinical hip OA was evaluated. Reporting is in accordance with proposed guidelines for the reporting of reliability and agreement studies (GRRAS). METHODS: In a university hospital, four blinded raters independently examined patients with unilateral hip OA; two hospital orthopaedists independently examined 48 (24 men) patients and two primary care chiropractors examined 61 patients (29 men). ROM was measured in degrees (deg.) with a standard two-arm goniometer and muscle strength in Newton (N) using a hand-held dynamometer. Reproducibility is reported as agreement and reliability between paired raters of the same profession. Agreement is reported as limits of agreement (LoA) and reliability is reported with intraclass correlation coefficients (ICC). Reliability of the overall assessment of clinical OA is reported as weighted kappa. RESULTS: Between orthopaedists, agreement for ROM ranged from LoA [-28-12 deg.] for internal rotation to [-8-13 deg.] for extension. ICC ranged between 0.53 and 0.73, highest for flexion. For muscle strength between orthopaedists, LoA ranged from [-65-47N] for external rotation to [-10 -59N] for flexion. ICC ranged between 0.52 and 0.85, highest for abduction. Between chiropractors, agreement for ROM ranged from LoA [-25-30 deg.] for internal rotation to [-13-21 deg.] for flexion. ICC ranged between 0.14 and 0.79, highest for flexion. For muscle strength between chiropractors, LoA ranged between [-80-20N] for external rotation to [-146-55N] for abduction. ICC ranged between 0.38 and 0.81, highest for flexion. Weighted kappa for the overall assessment of clinical hip OA was 0.52 between orthopaedists and 0.65 between chiropractors. CONCLUSIONS: Reproducibility of goniometric and dynamometric measurements of ROM and muscle strength in patients with hip OA is poor between experienced orthopaedists and between experienced chiropractors. Orthopaedists and chiropractors can to a moderate degree differentiate between hips with or without osteoarthritis.

No need for immediate freezing of metal ion blood samples in patients with metal-on-metal hip articulations.

INTRODUCTION: A recent British medical device alert suggested monitoring patients with metal-on-metal (MoM) articulations using blood metal ions. These blood samples are usually frozen immediately and shipped frozen for analysis. Simply posting the samples in the mail would lower the costs and simplify logistics of metal ion testing. The aim of this study was to determine whether the metal ion value in the blood is stable when kept at room temperature. MATERIAL AND METHODS: Eight patients with large-diameter MoM articulations were included. We compared levels of chromium (Cr) and cobalt (Co) in whole-blood samples frozen immediately, after four days and after 30 days. RESULTS: We found Co ranging from 0.64 to 10.9 µg/l and Cr from 0.76 to 5.16 µg/l. There was no systematic reduction in the mean level of Cr and Co of the eight patients when we compared results from the blood frozen immediately with the blood frozen after four days and after thirty days. There was a tendency towards greater variation (limits of agreement) in the results of the individual blood samples over thirty days, but these increases were non-significant. CONCLUSION: The variation of Co and Cr ions in blood kept at room temperature for up to thirty days is within clinically acceptable levels for the diagnosis of excess wear.

Bone mineral density of the femoral neck in resurfacing hip arthroplasty.

BACKGROUND AND PURPOSE: Resurfacing total hip arthroplasty (RTHA) may preserve the femoral neck bone stock postoperatively. Bone mineral density (BMD) may be affected by the hip position, which might bias longitudinal studies. We investigated the dependency of BMD precision on type of ROI and hip position. METHOD: We DXA-scanned the femoral neck of 15 resurfacing patients twice with the hip in 3 different rotations: 15 degrees internal, neutral, and 15 degrees external. For each position, BMD was analyzed with 3 surface area models. One model measured BMD in the total femoral neck, the second model divided the neck in two, and the third model had 6 divisions. RESULTS: When all hip positions were pooled, average coefficients of variation (CVs) of 3.1%, 3.6%, and 4.6% were found in the 1-, 2-, and 6-region models, respectively. The externally rotated hip position was less reproducible. When rotating in increments of 15 degrees or 30 degrees , the average CVs rose to 7.2%, 7.3%, and 12% in the 3 models. Rotation affected the precision most in the model that divided the neck in 6 subregions, predominantly in the lateral and distal regions. For larger-region models, some rotation could be allowed without compromising the precision. INTERPRETATION: If hip rotation is strictly controlled, DXA can reliably provide detailed topographical information about the BMD changes around an RTHA. As rotation strongly affects the precision of the BMD measurements in small regions, we suggest that a less detailed model should be used for analysis in studies where the leg position has not been firmly controlled.