Evaluating joint space widening and clinical outcomes after medial collateral ligament pie-crusting: All-inside versus outside-in techniques

Objectives: Medial collateral ligament (MCL) pie-crusting (PC) is a commonly employed technique to improve arthroscopic visualization and working space in the medial compartment of the knee, particularly during meniscal repair. Two principal approaches, All-inside and Outside-in, are used, but comparative evidence on joint space widening and functional outcomes remains limited. This study aimed to compare intraoperative joint space widening and post-operative clinical outcomes between the two techniques. Materials and Methods: This prospective comparative study included 30 patients with medial meniscal pathology requiring MCL PC during arthroscopy. Patients were randomly allocated to either the All-inside group ( n = 15) or the Outside-in group ( n = 15). Intraoperative medial joint space was measured using fluoroscopy at 30° knee flexion with valgus stress before and after PC. Clinical outcomes were assessed preoperatively and at 6 months postoperatively using the Lysholm score and Visual Analog Scale (VAS) for pain. Statistical analysis was performed using paired and unpaired t -tests, with p < 0.05 considered significant. Results: Both techniques significantly increased medial joint space intraoperatively (All-inside: mean increase 4.4 ± 1.14 mm; Outside-in: 5.26 ± 1.12; p < 0.001 for both). The mean difference in joint space widening between groups was not statistically significant ( p = 0.61). At 6 months, Lysholm scores improved significantly in both groups (All-inside: from 58.4 ± 5.2 to 89.3 ± 4.7; Outside-in: from 59.1 ± 6.0 to 90.1 ± 4.3; p < 0.001 within groups), with no intergroup difference ( p = 0.57). VAS pain scores decreased significantly in both groups without a significant difference between them. Conclusion: Both All-inside and Outside-in MCL PC techniques effectively widen the medial joint space and yield comparable short-term functional outcomes. The choice of technique may be based on surgeon preference and intraoperative considerations rather than expected differences in clinical results.