Limited information is published regarding the activity level after gracilis autograft reconstruction, and usually a knee-injury based score is used rather than a specific ankle PROM. The purpose of this study was to investigate the activity level and functional results after lateral ankle gracilis autograft reconstruction in patients with severe lateral ankle instability. The hypothesis was that patients would regain their pre-injury Tegner activity level or one level below and secondary to compare a specific ankle activity score, instability and function score. Finally, donor site and graft complications, clinical stability and range of motion were measured.

All 69 patients (50 women, 19 men) recorded at the hospital with severe instability who underwent reconstruction of the anterior talofibular and the calcaneofibular ligament with a gracilis autograft and were minimum 6 months post-operative, were invited to participate in the study. Outcomes measures included the Tegner Activity level (1–10), Ankle Activity Score (0–10) recorded as pre-injury and at follow up. The Karlsson Petterson Ankle Function Score (0–100) and Visual Analog Score (VAS)(0–10) recorded pre-operatively and at follow up. All pre-injury and pre-operative data were recalled retrospectively from memory. Identification of functional ankle instability (IDFAI)(0–37) was recorded at follow up. The clinical tests, Anterior drawer test (0–4), Talar tilt test (0–4) and Range of motion (ROM)(degrees) were compared to the unaffected side at follow up. A difference of 1 in the activity scores was chosen as a clinical relevant difference. Data was tested for normal distribution and for statistical significant difference with a students t-test. study design: Cross sectional clinical study with a retrospective questionnaire.

A total of 33 patients (27 women, 6 men), with a mean age on 45 years (range 19–68), were included in this study. Mean follow up was 3.7 years. Mean pre-operative Tegner score was 5.8 vs 5.6 at follow up (p

On average, the patients returned to their pre-injury activity level, with similar specific ankle activity scores to the Tegner. The majority had good functional results and few residual symptoms of functional instability. The response rate was low with few men responding; hence a prospective study is called for to establish the true effect of the surgical technique.

Radiostereometric analysis (RSA) can detect early micromovement in unstable implant designs which are likely subsequently to have a high failure rate. In 2010, the Articular Surface Replacement (ASR) was withdrawn because of a high failure rate. In 19 ASR femoral components, the mean micromovement over the first two years after implantation was 0.107 mm (sd 0.513) laterally, 0.055 mm (sd 0.204) distally and 0.150 mm (sd 0.413) anteriorly. The mean backward tilt around the x-axis was -0.08° (sd 1.088), mean internal rotation was 0.165° (sd 0.924) and mean varus tilt 0.238° (sd 0.420). The baseline to two-year varus tilt was statistically significant from zero movement, but there was no significant movement from one year onwards.

We conclude that the ASR femoral component achieves initial stability and that early migration is not the mode of failure for this resurfacing arthroplasty.

It is accepted that resurfacing hip replacement preserves the bone mineral density (BMD) of the femur better than total hip replacement (THR). However, no studies have investigated any possible difference on the acetabular side.

Between April 2007 and March 2009, 39 patients were randomised into two groups to receive either a resurfacing or a THR and were followed for two years. One patient’s resurfacing subsequently failed, leaving 19 patients in each group.

Resurfaced replacements maintained proximal femoral BMD and, compared with THR, had an increased bone mineral density in Gruen zones 2, 3, 6, and particularly zone 7, with a gain of 7.5% (95% confidence interval (CI) 2.6 to 12.5) compared with a loss of 14.6% (95% CI 7.6 to 21.6). Resurfacing replacements maintained the BMD of the medial femoral neck and increased that in the lateral zones between 12.8% (95% CI 4.3 to 21.4) and 25.9% (95% CI 7.1 to 44.6).

On the acetabular side, BMD was similar in every zone at each point in time. The mean BMD of all acetabular regions in the resurfaced group was reduced to 96.2% (95% CI 93.7 to 98.6) and for the total hip replacement group to 97.6% (95% CI 93.7 to 101.5) (p = 0.4863). A mean total loss of 3.7% (95% CI 1.0 to 6.5) and 4.9% (95% CI 0.8 to 9.0) of BMD was found above the acetabular component in W1 and 10.2% (95% CI 0.9 to 19.4) and 9.1% (95% CI 3.8 to 14.4) medial to the implant in W2 for resurfaced replacements and THRs respectively. Resurfacing resulted in a mean loss of BMD of 6.7% (95% CI 0.7 to 12.7) in W3 but the BMD inferior to the acetabular component was maintained in both groups.

These results suggest that the ability of a resurfacing hip replacement to preserve BMD only applies to the femoral side.

Resurfacing THA is claimed to transfer stress naturally to the femur neck and preserve proximal femoral bone mass postoperatively. DXA is an established method in estimating BMD around a standard THA, but due to the anteversion of the femur neck, rotation could affect the size of the neck-regions and thereby the BMD measurements around a RTHA. To our knowledge, this is the first study to analyze the effects of hip rotation on BMD in the femoral neck around a RTHA.

We scanned the femoral neck of 15 patients twice in each position of 15° inward, 0° and 15° outward rotation, and analyzed BMD in a single and a six-region model. CVs were calculated for BMD in the same position as well as between different positions.

For double measurements in the same position we found mean CVs of 3.1% (range 2.5% – 3.7%) and 4.6% (range 2.2% – 8.6%) in the one- and six-region models, respectively. When the 15° outward position was excluded, the CVs decreased to 2.8% and 4.0%. With rotation, the mean CVs rose to 5.4% (range 3.2%–7.2%) and 11.8% (range 2.7% – 36.3%). This effect was most pronounced in the 6-region model, predominantly in the lateral and distal parts of the femoral neck, where the change was significantly different from the fixated position. For the single-region model 15° rotation could be allowed without compromising the precision.

We conclude that rotation adversely affects the precision of BMD measurements around a RTHA, but in the single-region model smaller rotations can be allowed.

With the hip fixated the six-region model produces low CVs, acceptable for longitudinal studies. For maximal topographical detail we prefer the six-region model and recommend that future longitudinal DXA studies, including RTHA, be performed standardised, Preferably, with the hip in the neutral or internal rotation.