Long-term follow-up after primary repair of the anterior cruciate ligament: clinical and radiological evaluation 15–23 years postoperatively

We have previously reported results after 2–5 and 5–10 years follow-up of repair of acute anterior cruciate ligament (ACL) ruptures by suturing. Reports of results after more than 10 years are rare.

A total of 140 patients were operated on in the period 1975–1983 (age range 13–71 years, median 28 years) by the modified Palmer technique. Only 2 meniscus resections and 4 meniscectomies were performed at the primary operation; while 28 menisci were sutured. At follow-up,12 patients were dead. Eighteen patients (13%) underwent repeat operations for secondary instability. Of the remaining 110 patients, 81 appeared for follow-up.

Only 6 secondary meniscus resections were performed, all in the group of 18 patients operated on again for instability. No secondary meniscus surgery was performed on the 81 patients who appeared for follow-up. The median Lysholm score was 88, and 58 of the 81 patients (71%) classified their total knee function as good or excellent. By KT-1000 testing, 33 (41%) patients had less than 3 mm anterior instability, 29 (36%) had 3–5 mm instability, and 17 (21%) had more than 5 mm. With 18 patients from the total of 128 living patients re-operated for instability, we estimate the rate of total failure of stability as 27%. Radiological osteoarthritis grade C was present in 8 operated and 2 control knees, while only 1 operated knee revealed osteoarthritis grade D. Thirty-four operated and 20 control knees had grade B. Osteoarthritis was correlated to more advanced age at injury, while correlation to function could not be proven. Radiographs were obtained of 61 patients at follow-up.

Some 50% of patients had stable or slightly unstable knees, and 40% good or excellent function according to the Lysholm score. Re-operation for instability was more frequent in younger patients, while ostearthritis was more frequent in older patients. The rate of meniscus resection or extirpation was low. Open repair by suture is no longer recommended. Further research is indicated on the possible use of refixation of the ruptured ACL by arthroscopy.