Pinning and Arthroscopic Trimming for Mild Slipped Capital Femoral Epiphysis: Comparative Study With Traditional In Situ Pinning and Modified Dunn Procedure.

Abstract

Introduction: Mild slipped capital femoral epiphysis (SCFE) was traditionally treated with in situ pinning (ISP), a technique that stabilizes the physis but does not restore the anterior-superior femoral head offset. This residual deformity can lead to femoroacetabular impingement and early joint degeneration. Therefore, immediate arthroscopic trimming was associated to in situ pinning (ISPAT). The primary goal is to assess the clinical and radiologic outcomes of patients treated with ISPAT. Secondarily, outcomes were compared with traditional in situ pinning (ISP) and modified Dunn's procedure (MDP).

Methods: Patients with Southwick 1 SCFE were included. Patients were divided in 3 groups according to surgical treatment: (1) pinning in situ associated to arthroscopic trimming (ISPAT), (2) pinning in situ (ISP), and (3) modified Dunn procedure (MDP). Outcomes were assessed with clinical parameters (range of motion (ROM), impingement test, mHHS and UCLA activity score) and radiologic parameters (Southwick angle, alpha angle). Early and late complications were recorded. Comparative analysis was performed.

Results: A total of 47 patients (59 hips) were included in the study (ISPAT: 12, ISP: 34, MDP: 13). Preoperative Southwick slip angle (SA) was higher in the ISPAT and MDP groups compared with the ISP group (ISPAT vs. MDP, P=0.85; ISPAT vs. ISP, P<0.001; MDP vs. ISP, P<0.001)​. Surgical time differed between groups (ISPAT 69.9±17.7; ISP 37.0±21; MDP 140.0±26.5 min; P<0.001). The ISPAT group had a higher postoperative internal rotation (23.4±7.9 deg) compared with ISP (15.0±7.1 deg, P<0.001) but similar to MDP (28.2±6.4 deg; P=0.099). No differences were found in mHHS scores across groups (ISPAT 90.7±0.9, ISP 86.8±10.0, MDP 90.6±1.2, P=0.18)​. Postoperatively, the alpha angle of the ISPAT group demonstrated significant improvement postoperatively (preoperative 81.5±7.7 vs. postoperative 47.7±8.3 deg, P<0.001), with results comparable to MDP (postoperative 45.1±11.3 deg, P=0.45)​. In ISPAT no major complications were recorded. In ISP 4 patients developed osteoarthritis (OA) (2 required total hip arthroplasty). In MDP 1 patient developed OA, but no further surgery was performed.

Conclusions: ISPAT is a safe and effective option for managing mild SCFE, providing immediate intervention to address FAI. However, its long-term impact on hip function and osteoarthritis prevention requires further investigation.