Irreducible Dislocation of the Knee

Abstract

Irreducible knee dislocation is a rare injury. This case report describes a knee dislocation in a 39-year-old male U.S. Army noncommissioned officer who was injured while playing in a softball game. Arthroscopy showed the medial collateral ligament and capsule to be locked in the intercondylar notch, covering the medial femoral condyle. Arthrotomy and open reduction were required. Staged posterior cruciate ligament reconstruction using patellar tendon autograft was later performed. Review of the magnetic resonance imaging scan showed the irreducible lesion. The diagnostic clinical and radiographic features of this unusual injury are described.

Irreducible knee dislocation treated by arthroscopic debridement

“…[1][2][3][4][5][6][7][8][9][10][11] The majority were posterolateral dislocations. Where clinical information was available, the finding of a skin furrow along the medial joint line (which increased with attempts at reduction) was almost universal.…”

“…Where clinical information was available, the finding of a skin furrow along the medial joint line (which increased with attempts at reduction) was almost universal. [1][2][3][4][5][6][7][8][9][10][11] This finding was considered to be diagnostic of an irreducible dislocation by Brennan et al 2 Wand 11 because it denoted interposition of the medial soft tissues into the joint space. Nystrom et al 6 said this finding is characteristic of, but not pathognomonic of irreducible knee dislocations.…”

“…Commonly, the medial femoral condyle was found buttonholed through the capsuloligamentous structures at surgery. [2][3][4][5][6][7][8][9][10][11] Treatment varied and included open reduction alone, 1,2 open reduction and repair of the medial soft tissues, 3,4,7,11 open reduction and repair of 1 or both cruciate ligaments, 9 and repair of all torn ligaments. 5,6,8,11 Previously, arthroscopy has been used to visualize the cause of the irreducible dislocations but not to treat them.…”

“…5,6,8,11 Previously, arthroscopy has been used to visualize the cause of the irreducible dislocations but not to treat them. 8,9 We chose to debride the soft tissue through arthroscopic techniques, allowing the knee to be reduced.…”

“…A review of the English language literature found reports of 25 cases. [1][2][3][4][5][6][7][8][9][10][11] We present the cases of 2 patients with acute knee dislocations that were irreducible as a result of soft-tissue interposition. In neither case was the exact mechanism of injury known, although both patients described a hyperextension injury.…”