Poster 325: Untreated Ruptures of the Anterior Cruciate Ligament: a 54 Year Follow-Up Study

OBJECTIVES: Anterior cruciate ligament (ACL) ruptures are associated with instability, meniscus injuries, difficulties with sports, and ultimately post-traumatic osteoarthritis. End stage knee arthritis is often treated with total knee arthroplasty (TKA). To assess the effectiveness of any treatment for ACL injuries, the natural history of the ACL-deficient knee must be considered. The objective of this longitudinal study is to establish a baseline by tracking the objective and subjective outcomes of ACL-deficient knees over 54 years. Results are analyzed in light of the 6 previous iterations of this study to assess the natural history of the ACL-deficient knee. METHODS: This is the sixth iteration of a retrospectively established cohort of 50 patients whose isolated ACL ruptures were surgically verified between 1960 and 1974 but left unreconstructed. When the cohort was established, 3 patients had verified bilateral ACL-deficient knees; thus, there are a total of 53 studied knees in the original cohort. None of the knees included in the study had other ligamentous injuries at index arthrotomy. Knees with meniscal injuries were not excluded from the study. Meniscus injuries were treated with complete medial and/or lateral meniscectomy, as was standard at the time. This cohort has been evaluated via questionnaires, radiographs, and examinations at 10, 14, 19, 29, 44, and currently 54 years since ACL injury. Marshall, Lysholm, and Fairbanks scores were used to objectively assess stability, functionality, and radiographic changes, respectively. The same questionnaire, with only minor updates, has been used in each iteration to gather information regarding exercise habits, activity levels, symptoms, and other pertinent information. RESULTS: All 53 knees were accounted for—no member of the original 1975 cohort was permanently lost to follow-up. 5 were excluded due to unrelated disability or illness. At final follow-up, 32 of the 48 (66.7%) included knees were native. Of these, 15 are still living and were reevaluated. The remaining 16 (33.3%) had undergone TKA. The mean age at ACL injury was 18.3 years (standard deviation 6.72). The mean time elapsed between injury and index arthrotomy was 7.56 months (standard deviation 7.05 years). At index arthrotomy, 31 of the 48 (64.6%) studied knees underwent complete medial meniscectomy, 4 (8.33%) knees underwent complete lateral meniscectomy, 1 (2.08%) knee underwent both medial and lateral meniscectomy, and the remaining 9 (18.8%) knees did not undergo either medial or lateral meniscectomy. In the interim between index surgery and final follow-up, 20 of 48 (41.7%) knees underwent additional knee surgery. 2 of these 20 underwent multiple late surgeries; both knees ultimately required TKA. 2 of the 20 were articular cartilage repairs; both knees ultimately required TKA. 6 were late ACL- reconstructions; 4 of these eventually underwent TKA. 1 was an unrelated tumor excision. 7 knees underwent late medial meniscectomy and 4 knees underwent late lateral meniscectomy. Of the 9 knees that did not undergo meniscectomy at the time of index arthrotomy, 1 underwent late medial meniscectomy and did not ultimately require TKA, 1 underwent late lateral meniscectomy and did ultimately require TKA, and 2 underwent late medial and lateral meniscectomy, 1 of which required TKA. At final follow-up, 27 of the 48 knees (56.3%) had undergone only medial meniscectomy, 7 (25.9%) of which required TKA. 4 (8.33%) studied knees underwent only lateral meniscectomy, 2 (50.0%) of which required TKA. 12 of the 48 (25.0%) underwent both medial and lateral meniscectomies and 6 (50.0%) of these knees ultimately underwent TKA. Notably only 1 of these 12 (8.33%) knees underwent both medial and lateral meniscectomy at index arthrotomy; this individual did not undergo TKA. 5 of the 48 (10.4%) knees did not undergo meniscectomy at any point. 1 of the 5 (20.0%) knees without a history of meniscectomy underwent TKA; this knee had an articular cartilage injury at index surgery. Of the 11 knees with articular cartilage injury at index arthrotomy, 4 (36.4 %) ultimately underwent TKA. An additional 5 knees had late articular cartilage injuries, 3 (60.0%) of which eventually underwent TKA. Thus, 16 of the 48 (33.3%) had a known history of articular damage, 7 (43.8%) of which underwent TKA. When the study began, only 3 patients had verified bilateral ACL deficiency. Since then, 9 more patients ruptured their contralateral ACL. Though these knees were not retrospectively entered into the study, 12 of 48 (25.0%) patients had documented bilateral ACL-deficiency at final follow-up. 9 (18.8%) knees were replaced between 29- and 44-year follow-up. 7 (14.6%) knees were replaced between 44- and 54- year follow-up. The mean age at TKA was 58.7 years, a mean of 41.0 years after ACL injury. The median Marshall score of this cohort was 37 at 10-year follow-up, 38 at 14-year follow-up, 36 at 29- year follow-up, and 41 at 54-year follow-up. 15 of 32 native knees were still living. All were reassessed. The mean age was 69.3. 5 knees were described by the patient as excellent, 5 as good, 3 as fair, and 2 as poor. 5 caused no pain, 6 caused mild pain, 4 caused moderate pain, and 0 caused severe pain. 3 received injections in the last 10 years. 0 took prescription anti-inflammatories or pain medications. 0 reported the knee hinders activities of daily living. 6 knees did not interfere with sports. 1 prevented sports. The remaining 8 no longer play sports. 9 knees were examined and radiographed. All were grossly stable. All showed radiographic evidence of osteoarthritis. Conclusions: ACL injury leads to post-traumatic osteoarthritis. While 33.3% of this cohort ultimately required TKA, 66.7% have coped relatively well with ACL-deficiency through late adulthood. To our knowledge, this is the first study to track ACL-deficient knees over 54 years.