A rare combined injury of the cruciate ligament and occult tears of the medial and lateral heads of the gastrocnemius muscle: A case report.

The diagnosis and treatment of high-energy knee trauma primarily focus on ligamentous and bony injuries, often overlooking potential concomitant gastrocnemius muscle injuries. Isolated closed tears of the medial and lateral heads of the gastrocnemius muscle (without associated fractures or dislocations) are exceptionally rare and clinically insidious, increasing the risk of missed diagnosis and compromised patient outcomes. This article presents a novel case of combined cruciate ligament injury and occult tears of both gastrocnemius heads, a condition not previously documented in the literature. A 53-year-old male was injured by a car and suffered a wound on his left knee. He presented with obvious symptoms of pain, swelling, and limited mobility. The physical examination showed positive Lachman test, anterior and posterior drawer tests, and pivot shift test. Resistance to plantar flexion was weak. The floating patella sign was positive. The McMurray test was suspiciously positive. Combined with magnetic resonance imaging (MRI), the diagnosis was anterior and posterior cruciate ligament injuries of the left knee joint. After the anesthesia, the patient was reexamined. The result showed that the left knee joint was obviously overextended. Eventually, it was confirmed as anterior and posterior cruciate ligament injuries combined with rupture of the medial and lateral heads of the gastrocnemius muscle. A staged surgical approach was employed: primary posterior capsular and gastrocnemius repair, followed by secondary arthroscopic anterior and posterior cruciate ligament reconstruction. Six months after discharge from the hospital, the patient underwent a reexamination with MRI, the results were satisfactory. The patient was able to walk without pain and regain mobility. There was no sensation of instability in the knee joint. This case highlights that isolated gastrocnemius tears are diagnostically challenging but must be considered in hyperextending knees, examination under anesthesia enhances detection of occult instability, while MRI is a valuable diagnostic tool, its interpretation should be integrated with clinical findings to ensure that subtle soft tissue injuries are not overlooked.