Abstract

Anterior cruciate ligament (ACL) injuries are common in athletic population. Hyperlaxity is thought to be a risk factor for ACL injuries and results in stretched scar following surgery. The aim of our study was to investigate the relationship between the strength of the knee skin and hyperlaxity assessed by the Beighton score. Prospective data was collected for 13 patients undergoing primary ACL reconstruction using quadruple hamstring tendon as a graft, including demographic details, mechanism of injury and hyperlaxity. Clinical examination was used to assess hyperlaxity using the Beighton score. Laxity is scored on a 0–9 scale. Scores of 4 or above are indicative of hyperlaxity. We studied 20 specimens of knee skin from 13 patients between Nov 2008 and July 2009. These specimens were mounted on a professional material testing system (ZWICK- allround line) and vertical load was applied to reach yield. Data was recorded electronically and analysed using Microsoft excel. The mean age was 29 years with a range from 20 to 43. Most common sports resulting in ACL injuries were football and skiing in 3 patients each followed by rugby and cycling in 2 patients each. There were 10 male and 3 female patients. The average Beighton score was 2.9 with a range from 0 to 9. 5 patients had a Beighton score of 4 or more indicating hyperlaxity. The average force required to reach yield for knee skin was 56 N with a range from 12 to 107 N. There was no correlation between the force required for yield and Beighton score for patients individually. We studied the force required to produce yield of the knee skin in athletes undergoing ACL reconstruction and found no correlation between hyperlaxity and the force. This data does not show an obvious link between hyperlaxity and the strength of the knee skin for patients individually. The stretched scars following surgery in patients with hyperlaxity may be associated with the method of skin closure and further studies are needed to assess this relation and prevent wound related complications.