Poster 346: Revision Anterior Cruciate Ligament Reconstruction with an All-Soft Tissue Quadriceps Tendon Autograft Produces Similar Outcomes to Index Surgery

OBJECTIVES: Anterior cruciate ligament reconstruction (ACLR) using all-soft tissue quadriceps tendon (QT) autograft has not yet been studied as a viable revision option in the pediatric population. This study aimed to compare short- to mid-term outcomes between patients undergoing revision ACLR and primary ACLR using all-soft tissue QT autograft. METHODS: A retrospective review of prospectively collected data included patients aged 8-18 years old who underwent revision ACLR using an all-soft tissue QT autograft over a ten-year period (2011-2021). One-to-two matching by age and gender was performed to select a control group of patients who underwent primary ACLR utilizing all-soft tissue QT autograft during the same period. All procedures were performed by a single surgeon using a minimally invasive graft harvest technique and suspensory fixation. Subjective assessment of knee function was obtained pre- and postoperatively with the International Knee Documentation Committee (IKDC) survey. Postoperative knee laxity was measured with a KT1000 arthrometer at 6 weeks, 3 months, and 6 months. Isokinetic quadriceps strength at 60° and 180° was collected at 6 months and 12 months. Complications, including hematomas, infections, graft failures, and the need for subsequent surgery were recorded. To determine clinical significance (p≤0.05), outcomes were compared using two-sided Student t-tests and Pearson’s chi-squared tests. RESULTS: Thirty-nine patients underwent revision ALCR (59% female; 15.67±1.6 years old; BMI 23.7±4.6) and 78 underwent primary ACLR (59% female; 15.73±1.46 years old; BMI 23.5±3.9) with all-soft tissue QT autograft (p=1.00 for gender; p=0.83 for age; p=0.82 for BMI). Length of follow up was 20.9 months (revision) and 23.4 months (primary) (p=0.543). Mean IKDC scores improved significantly in both groups (Revision: 59.17±16.4 vs. 85.87±10.57, p<0.001; Index: 55.85±16.8 vs. 88.38±14.2 p<0.001). Mean time to postoperative IKDC for revision and primary ACLR was 14.67±5.7 months and 15.22±6.5 months, respectively (p=0.865). There were no significant differences in mean pre- or postoperative IKDC scores between the index and revision groups (Table 1, p>0.05). However, postoperative knee laxity was significantly greater after revision surgery at 6 weeks (p=0.006) and 6 months (p=0.009) (Table1). Contrarily, patients undergoing primary surgery had a greater isokinetic quadriceps strength deficit during both time points at 60° and 180°, which was statistically significant at full extension at 12 months postoperatively (p<0.039) (Table 1). Finally, although patients undergoing revision surgery exhibited fewer complications, this difference was not statistically significant (Table 2). CONCLUSIONS: Patient reported outcomes after ACLR revision surgery using all-soft tissue QT autograft in the paediatric population is equivocal to those undergoing primary reconstruction. Despite minor differences in the progression of postoperative isokinetic strength and knee laxity, a history of previously failed ACLR does not seem to portend inferior outcomes or increased risk for complications in pediatric patients undergoing revision surgery with all-soft tissue QT autograft.