The Use of Allograft Tissue for Primary ACL Reconstruction is Associated with Increased Odds of Progression of Patellofemoral Articular Cartilage Damage Between Primary and Revision Surgery
Authors:   MARS Group
Published: July 2017

Objectives: Subsequent development of osteoarthritis remains a major problem following anterior cruciate ligament (ACL) injury and reconstruction. Progression of articular cartilage damage likely precedes clinical symptoms of osteoarthritis in these patients. The purpose of this study was to examine risk factors affecting progression of articular cartilage damage in the patellofemoral joint between primary ACL reconstruction and revision ACL reconstruction. Methods: Subjects who had both primary and revision data contained in two prospective cohort studies were included in the analysis. Data reviewed included patellar and trochlear articular cartilage status (modified Outerbridge grade and size) at time of primary and revision; meniscus status at time of primary reconstruction; time from primary to revision ACL surgery; patient age, sex, and body mass index (BMI); smoking status; primary reconstruction graft type; and Marx activity scale prior to revision surgery. Significant patellofemoral chondral surface change was defined as worsened Outerbridge grade or at least 25% enlargement of the area of cartilage damage between primary and revision surgery. Logistic regression using a forward selection methodology used to determine which factors at primary reconstruction were associated with increased odds of progression of patellofemoral articular cartilage damage at the time of revision reconstruction. Results: A total of 134 subjects met inclusion criteria. Progression of patellofemoral articular cartilage damage between primary and revision surgery was noted in 31 of the 134 patients (23.1%). Median age at time of revision was 19.5 years [IQ range 17-25 years] and median time from primary to revision was 15.2 months [IQ range 9.6-34.4 months]. The use of allograft for the primary reconstruction, increased BMI, and increased time from primary to revision surgery were associated with increased risk of progression of articular cartilage damage in the patellofemoral joint. The use of allograft was associated with a 15-fold increased odds of progression of articular cartilage damage relative to a patellar tendon autograft (OR = 15.5, 95% CI = 3.2-75.3, p = 0.001). The use of a hamstring autograft was not associated with significantly increased odds of progression relative to patellar tendon autograft (OR = 4.3, 95% CI = 0.8-22.4, p = 0.08) Each one unit increase in BMI at the time of revision surgery was associated with a 10% increased in the odds of progression of articular cartilage damage (OR = 1.11, 95% CI = 1.00-1.22, p = 0.046). Each one month increase in time from primary to revision surgery was associated with a 2% increased in the odds of progression of articular cartilage damage (OR = 1.02, 95% CI = 1.00-1.04, p = 0.047). No other potential predictors were associated with increased odds of progression, including age, activity level prior to revision surgery, and meniscus status at primary reconstruction. Conclusion: The use of allograft for the primary reconstruction, increased BMI, and increased time from primary to revision surgery were associated with increased risk of progression of articular cartilage damage in the patellofemoral joint. Potential explanations for the association of articular cartilage damage progression and the use of allograft require further research, but do not appear to be related to patient age or Marx activity level prior to revision ACL reconstruction.