Problems in regaining full extension of the knee after anterior cruciate ligament reconstruction: does arthrofibrosis exist?

A total of 194 patients was reviewed after ACL reconstruction using a patellar tendon graft or Leeds-Keio prosthesis supplemented with a MacIntosh lateral substitution. There were five groups of patients: patellar tendon with cast immobilisation in flexion (n = 34); restricted extension but no cast (n = 40); immediate full extension (n = 40); 40); immediate full extension with notch widening (n = 40); Leeds-Keio ligament prosthesis (n = 40). The incidence of a click or a block to extension requiring operation ranged from 59% following cast immobilisation to 2.5% with the Leeds-Keio ligament. The incidence was significantly less when a Leeds-Keio prosthesis was used, and these problems may be associated with biological materials only. Restricting extension after operation significantly increased the loss of extension, confirming the work of others. Loss of extension was due to a mechanical block in all cases examined arthroscopically. All were relieved by arthroscopic surgery, and no case of flexion contracture or arthrofibrosis was encountered. A simple mechanical block to extension caused by a Cyclops lesion should be clearly distinguished from flexion contracture and arthrofibrosis, conditions which are probably extremely rare and overdiagnosed.