OBJECTIVETo study the application of stress X-ray of knee joint for the diagnosis ot medial collateral ligament injury.

METHODSFrom January 2008 to June 2011, 46 patients with medial collateral ligament injury were reviewed. Among the patients, 32 patients were male and 14 patients were female, ranging in age from 28 to 72 years, with an average of (49.46 +/- 22.54) years. Left knee joint injuries occurred in 22 patients, and 24 patients had injuries in right knee joint. Thirty-one patients were treated with surgical method, and 15 patients were treated with conservative method including 1 patient finally received operation after 3 months treatment with conservative method without effect. The injury side and normal side were observed by X-ray under stress and non-stress, as well as MRI. Operation was used to treat patients with medial gap markedly widen and the deep layer of medial collateral ligament injury in MRI. A line (line A) was drawn from medial condyle to lateral condyle of tibia platform. The line A was translated to the inner margin of condylus medialis femoris, which was line B. The perpendicular distance was measured, which was line C. The ration of space difference (R) was calculated by (space at stress force of injured side-space at non-stress force of injured side)/(space at stress force of normal side-space at non-stress force of normal side). The relationship between R and ligament injury type were investigated.

RESULTSThere were 17 patients with injuries of superficial lamella, 21 patients with injuries of deep lamella. Eight patients had associated injuries of articular capsule and posterior cruciate ligament. When R value was between 1.51 to 5.24, the injury of superficial ligament was found in 15 patients, actual injuries were found in 17 patients. When R value between 5.28 and 13.85, the injuries of bathypelagic ligament were found in 19 patients, actual injuries were found in 21 patients. When R value was between 15.61 and 26.25, the associated injuries of articular capsule and posterior cruciate ligament were found in 7 patients, actual injuries were found in 8 patients.

CONCLUSIONUsing the specific value as the standard of measurement can provide the quantizatily fractionation of the medial collateral ligament injury.