Purpose: We present the results obtained in a consecutive series of 48 patients who underwent surgical repair for chronic posterior knee laxity between 1995 and 2000.

Material and methods: The series included 33 men and 15 women, men age 29 years at the time of trauma. Mean duration of knee laxity before surgery was 32 months: 26 patients had undergone different procedures but without reconstruction of the posterior cruciate ligament (PCL). Preoperative physical examination revealed direct posterior laxity (DPL in 17 knees, posteroposterolateral laxity (PPLL) in 17, posteroposteromedial laxity (PPML) in 6, global posterior laxity (GPL) in one, and complex anteroposterier laxity (APL) in 7. The PCL was reconstructed arthroscopically using a two-strand graft using either the patellar tendon for the oldest cases (n=22) or the quadriceps tendon (n=26). Peripheral involvement was repaired by tension, reinforcement, or reconstruction with an autologous tendon graft. In the event of associated genu varum, a tibial osteotomy for normo-correction was also performed prior to the ligamentoplasty. Outcome was assessed with the IKDC 93 criteria and posterior laxity was measured on the stress x-rays.

Results: All patients were followed at least one year. Mean follow-up was 24 months. There were no postoperative complications. The principal results for the first three types of laxity, DPL, PPLL, and PPML, were as follows. Preoperative subjective evaluation for the entire series: 12C, 36D; symptoms: 6B, 10C, 32D; global score: 9C, 39D; laxity: 11.4±4.3 mm. DPL: subjective evaluation: 4C, 13D; symptoms: 2B, 2C, 12D; global score: 4C, 14D; laxity 9.9±3.3 mm. PPLL subjective evaluation: 7C, 10D; symptoms: 2B, 6C, 9D; global score: 3C, 14D; laxity 11.7±4.6 mm. PPML subjective evaluation: 6D; symptoms: 1B, 5D; global score: 6D; laxity 13.0±3.7 mm. At last follow-up for the entire series, subjective evaluation: 9A, 27B, 12C; symptoms: 6A, 26B, 14C; global score: 1A, 25B, 21C, 1D; laxity: 5.0±3.0 mm, giving a 62% gain. DPL subjective evaluation: 6A, 8B, 3C; symptoms: 5A, 10B, 2C; global score: 1A, 10B, 6C; laxity: 4.0±2.0 mm, giving a 62% gain. PPLL subjective evaluation: 2A, 11B, 14C; symptoms: 3A, 10B, 4C; global score: 4B, 12C, 1D: laxity: 5.7±3.5 mm, giving a 54% gain. PPML subjective evaluation: 6B; symptoms: 6B; global score: 5B, 1C; laxity: 5.9±3.0 mm, giving a 61% gain. For all parameters considered, category D disappeared at last follow-up in almost all knees. This improvement over the preoperative status was statistically significant (p=0.001).

Discussion: Reconstruction of the PCL with a two-strand graft combined with compensation of peripheral laxity and axial deviations provides significant correction in laxity similar to that obtained for the anterior cruciate ligament. Despite these satisfactory results, posteroposterolateral laxity has a less favourable prognosis than the other types of laxity.