Acute hemarthrosis of the knee: indications for diagnostic arthroscopy.

The objective of this study was to define the role of early diagnostic knee arthroscopy for patients with an acute knee injury and hemarthrosis. Forty-five patients with an acute knee injury followed by a posttraumatic hemarthrosis during a 1-year period were prospectively reviewed. All patients were evaluated preoperatively followed by examination under anesthesia and arthroscopy of the knee. The majority of patients, 32 (71%), had an anterior cruciate ligament tear. Meniscal tears occurred in 21 patients (47%). Meniscal tears requiring surgery occurred in only 10 of 25 meniscal tears (40%). Seven patients (16%) had medial collateral ligament and/or posteromedial capsular sprain. Eight patients (18%) had an osteochondral fracture or patellar dislocation associated with an osteochondral fracture. The majority of knees with a torn meniscus or osteochondral fracture had an anterior cruciate ligament tear. Clinically, 18 of 21 knees (86%) with an acute complete anterior cruciate ligament tear were diagnosed preoperatively with the Lachman test. The Lachman test conducted with patients under anesthesia was positive for 19 of 21 knees (90%) with an acute complete anterior cruciate ligament tear. The preoperative examination correctly identified six of seven knees (86%) with a medial collateral ligament sprain. The preoperative Lachman test was positive in only two of five knees (40%) with a partial anterior cruciate ligament tear. The Lachman test with patients under anesthesia was positive for four of five knees (80%) with an acute partial anterior cruciate ligament tear. Preoperative examination yielded the correct diagnosis in only 9 of 21 knees (43%) with a meniscal tear and 1 of 6 knees (17%) with an osteochondral fracture.(ABSTRACT TRUNCATED AT 250 WORDS)