Paper 40: Early Clinical Outcomes Following Anterior Cruciate Ligament Reconstruction with Quadriceps Tendon Autograft in an Adolescent Population Suggest Higher Rates of Arthrofibrosis with Bone-Block than All Soft Tissue.

OBJECTIVES: There is an increased interest in quadriceps tendon autograft for anterior cruciate ligament (ACL) reconstruction in the adolescent population. It has emerged as a promising graft option that can be harvested with a bone-block (BB) or all soft tissue (AST). The preferred quadriceps graft remains controversial as there is evidence that bone to bone healing is stronger and faster, while AST grafts reportedly have a lower complication rate. The purpose of this study is to report early clinical outcomes following ACL reconstruction with BB versus AST quadriceps autograft in adolescent population. We hypothesized that both techniques would provide similar early clinical outcomes. METHODS: A retrospective case-controlled study of patients under 20 years of age who underwent arthroscopic ACL reconstruction utilizing quadriceps tendon autograft from September 2017 to September 2021 was conducted. The cohort was divided in two groups: Group 1 included 35 patients who underwent ACL reconstruction with BB quadriceps tendon autograft. Group 2 included 58 patients who underwent ACL reconstruction with AST quadriceps tendon autograft. Data collected included demographics, range of motion, graft measurements, concomitant procedures, perioperative complications and arthrofibrosis rate, defined as reoperation for lysis of adhesions. Knee strength was objectively recorded at 3 months postoperatively using an isokinetic dynamometer (Humac, CSMI USA, Stoughton, MA, USA) and was used to calculate the Limb Symmetry Index (LSI), or the ratio between the involved limb and uninvolved limb and expressed as a percentage. Patient reported outcomes include International Knee Documentation Committee (IKDC) and Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI) scale. Statistical analyses were then performed to compare groups. RESULTS: A total of 93 patients were included for analysis, with mean age of 15.9 (range 10-20) and mean follow-up 17 months (ranged from 3 to 25). There was no difference between the study and control groups regarding age (p=0.10), BMI (p=0.70), concomitant procedures (p=0.39), but there was a predominance in females in group 1 (bone block) (64.9% vs 43.3%, p=0.02). The group 1(bone block) was associated with higher rate of arthrofibrosis with odds ratio of 3.98 (7/35 20% vs 3/58 5%, p=0.02) and lower LSI (55.6% vs 68.4%, p=0.01) at 3 months postoperatively. Group 1 (bone block) grafts were overall greater in femur width (9.47 vs 9.19, p=0.02), and length (69.85 vs 65.12, p=0.01). Logistic regression found BB quadriceps tendon graft (p=0.03) and extension deficit at 3 months postoperatively (p=0.01) the only risk factors for arthrofibrosis. Patients in group 1 (bone block) reported lower outcomes scores than group 2 (all soft tissue), measured by IKDC 63.94 vs 75.27 (p=0.01) and (ACL-RSI) 49.55 vs 63.25 (p=0.01) at 3 months postoperatively. CONCLUSIONS: Comparative analysis between bone block and all soft tissue quadriceps tendon autograft for ACL reconstruction in an adolescent population demonstrates that bone block QT autograft is associated with 4 times higher rate of arthrofibrosis requiring operative intervention for lysis of adhesions. If surgeons opted for a bone block QT autograft for ACL reconstruction in the adolescent population, our findings suggest that an early rehabilitation program with a focus on early restoration of full knee extension should be implemented in order to avoid arthrofibrosis.