LOWER-EXTREMITY MORPHOLOGY AND ALIGNMENT AND RISK OF OVERUSE INJURY

Objective: Lower extremity alignment factors, including tibiofemoral a ngle, quadriceps angle (Q-angle), and limb length discrepancies, are c ommonly thought to be clinically relevant as contributing factors to o veruse injuries of the lower extremities. To explore the scientific ra tionale for these clinical beliefs, we conducted a review of the avail able English language literature from 1966 to July 1997 relating overu se injury to lower extremity alignment. Data Sources: MEDLINE was sear ched for medical subject headings and title key words to locate publis hed works relating lower extremity morphologic characteristics to risk of overuse injury. Additional references were reviewed from reprint c ollections and reference lists of published work. Data Extraction and Synthesis: Relevant studies were reviewed for strengths and weaknesses in design, analysis, and conclusions. Synthesis across studies concen trated on commonalities and differences of methods in definition of ex posure and outcome variables. Main Results: Six population-based studi es have been conducted evaluating some aspect of lower extremity align ment as a risk factor for overuse injury. Three of these studies evalu ated military recruits in basic training, two studied mixed groups of athletes, and one studied folk dancers. The time frame across studies ranged from 12 weeks to 52 weeks. A key finding was the considerable v ariation in the measure of lower limb alignment used as the exposure v ariable, as well as the method of measurement used to quantify the exp osure. Some studies relied on visual examination, whereas others used digitized photographic techniques. Moreover, each study varied in the definition used for overuse injury, outcomes ranged from self-reported cases of shin splints to radiographic confirmation of stress fracture . Five of the six studies evaluated some aspect of foot morphology, wh ereas only one evaluated full leg alignment parameters. Conclusions: R esults were conflicting but, in general, did not support clinical beli efs of the detrimental effects of decreased longitudinal foot arch and varus tibiofemoral alignment as risk factors for lower extremity over use injury. Differences in methodologic rigor and outcome definition p revent a meaningful synthesis of existing work. Directions for future research are suggested.