This study sought to determine the genetic contribution of Perthes' disease, using the world's largest twin-registry. We extracted all twin pairs from the Danish Twin Registry (DTR) in which at least one individual had Perthes' Disease. The DTR captures every twin pair born alive in Denmark. Those with Perthes' disease were identified using health record linkage to the Danish Morbidity Record. Probandwise concordance was calculated to describe the likelihood that any given individual had LCPD if their co-twin was also diagnosed. There were 81 twin pairs; 10 monozygotic (MZ), 51 dizygotic (DZ), and 20 unclassified (UZ). There was no association between birth weight and being the affected co-twin. Four pairs (two dizygotic and two unclassified) were concordant for LCPD, which is greater than would be expected assuming no familial aggregation. There were no concordant MZ twin pairs. The overall probandwise concordance was 0.09 (95% CI 0.01–0.18): 0.00 for the MZ, 0.08 (95% CI 0.00–0.18) for the DZ, and 0.18 (95% 0.00–0.40) for the UZ twin pairs. This study found evidence of familial clustering in LCPD but did not demonstrate a genetic component. The absolute risk that a co-twin of an affected individual will develop LCPD is low, even in the case of MZ twin pairs.
Acute achilles tendon ruptures are increasing in incidence and occur in 18 per 100 000 people per year, however there remains a lack of consensus on the best treatment of acute ruptures. Randomised studies comparing operative versus non-operative treatment show operative treatment to have a significantly lower re-rupture rate, but these studies have generally used non-weight bearing casts in the non-operative group. Recent series utilizing more aggressive non-operative protocols with early weight-bearing have noted a far lower incidence of re-rupture, with rates approaching those of operative management. Weight bearing casts may also have the advantages of convenience and an earlier return to work, and the purpose of this study was to compare outcomes of traditional casts versus Bohler-iron equipped weight-bearing casts in the treatment of acute Achilles tendon ruptures. 83 patients with acute Achilles tendon ruptures were recruited from three Auckland centres over a 2 year period. Patients were randomised within one week of injury to receive either a weight-bearing cast with a Bohler iron or a traditional non weight-bearing cast. A set treatment protocol was used, with a total cast time of eight weeks. Patients underwent detailed muscle dynamometry testing at 6 months, with further follow up at 1 year and at study completion. Primary outcomes assessed were patient satisfaction, time to return to work, and overall re-rupture rates. Secondary outcomes included return to sports, ankle pain and stiffness, footwear restrictions, and patient satisfaction. There were no significant differences in patient demographics or activity levels prior to treatment. At follow up, 1 patient (2%) in the Bohler iron group and 2 patients (5%) in the non weight bearing group sustained re-ruptures (p=0.62). There was a trend toward an earlier return to work in the weight-bearing group, with 58% versus 43% returning to work within 4 weeks, but the difference was not significant. 63% of patients in the weight bearing group reported freedom from pain at 12 months compared to 51 % in the non weight bearing group. There were no statistically significant differences in Leppilahti scores, patient satisfaction, or return to sports between groups. Weight-bearing casts in the non-operative treatment of Achilles tendon ruptures appear to offer outcomes that are at least equivalent to outcomes of non-weight bearing casts. The overall rerupture rate in this study is low, supporting the continued use of initial non-operative management in the treatment of acute ruptures.
