The risk of AVN is high in Unstable Slipped Capital Femoral Epiphysis (SCFE) and the optimal surgical treatment remains controversial. Our AVN rates in severe, unstable SCFE remained unchanged following the introduction of the Modified Dunn Procedure (MDP) and as a result, our practice evolved towards performing an Anterior Open Reduction and Decompression (AOR) in an attempt to potentially reduce the “second hit” phenomenon that may contribute. The aim of this study was to determine the early surgical outcomes in Unstable SCFE following AOR compared to the MDP. All moderate to severe, Loder unstable SCFEs between 2008 and 2022 undergoing either an AOR or MDP were included. AVN was defined as a non-viable post-operative SPECT-CT scan. Eighteen patients who underwent AOR and 100 who underwent MPD were included. There was no significant difference in severity (mean PSA 64 vs 66 degrees, p = 0.641), or delay to surgery (p = 0.973) between each group. There was no significant difference in the AVN rate at 27.8% compared to 24% in the AOR and MDP groups respectively (p = 0.732). The mean operative time in the AOR group was 24 minutes less, however this was not statistically significant (p = 0.084). The post-reduction PSA was 26 degrees (range, 13–39) in the AOR group and 9 degrees (range, -7 to 29) in the MDP group (p<0.001). Intra-operative femoral head monitoring had a lower positive predictive value in the AOR group (71% compared to 90%). Preliminary results suggest the AVN rate is not significantly different following AOR. There is less of an associated learning curve with the AOR, but as anticipated, a less anatomical reduction was achieved in this group. We still feel that there is a role for the MDP in unstable slips with a larger remodelling component

Introduction

In situ pinning for classic slipped capital femoral epiphysis(SLIP) is evolving to a more direct and anatomic realignment of proximal femoral epiphysis; but in no study the result of such a treatment in Valgus Slip, an uncommon type of slipped capital femoral epiphysis, has been reported.

The modified Dunn procedure has the potential to restore the anatomy in hips with slipped capital femoral epiphyses (SCFE) while protecting the blood supply to the femoral head. However, there is controversy about the risks associated with the procedure especially in the most severe capital slips.

Therefore, we report on (1) clinical outcome, (2) the cumulative survivorship with endpoints AVN and/or OA progression and (3) radiographic anatomy of the proximal femur at followup in patients treated with a modified Dunn procedure for severe SCFE.

We performed a retrospective analysis involving 46 hips of 46 patients treated with a modified Dunn procedure for severe SCFE (slip angle >60°) between 1999 and 2016.

Followup averaged 8 years, (range 1–17) with 2 patients lost to followup after one year.

The mean age was 13 years (range 9–19 years). Mean preoperative slip angle was 64° (range 60–90) and 14 out of 46 hips (30%) presented with unstable slips.

Clinical scores and PROMs were evaluated and the hips were followed standard x-rays. Cumulative survivorship (Kaplan-Meier) with three defined endpoints: (1) AVN; (2) progression by at least one OA grade according to Tönnis; (3) non-preserved hip joint.

(1)Mean Harris Hip score (HHS) was 93 points (66–100) and mean Hip Disability and Osteoarthritis Outcome Score (HOOS) was 90 points (67–100) at last followup.

(2)Cumulative survivorship was 93% at 10-year followup. Three hips reached an endpoint. Two hips (4%) had AVN, one of them underwent hip arthrodesis. One hip had OA progression.

(3)Postoperative slip angle was 7° (1–16). Alpha angle on axial radiograph was 39° (26–71) at followup. 41/44 hips (93%) had no OA (Tönnis 0).

The modified Dunn procedure largely corrected slip deformities with low apparent risk of progression to avascular necrosis or osteoarthritis at mean 8-years followup. The AVN rate in severe and unstable (30%) capital slip was 4% (2 hips) with this procedure.

Introduction

Hips following in-situ pinning for slipped capital femoral epiphysis (SCFE) have an altered morphology of the proximal femur with cam type deformity. This deformity can result in femoroacetabular impingement and early joint degeneration. The modified Dunn procedure allows to reorientate the slipped epiphysis to restore hip morphology and function.

Chronic instability of the acromioclavicular joint is relatively common and normally occurs following a fall onto the point of the shoulder. Reconstruction of the joint (Weaver-Dunn procedure) is often required in service personnel, and numerous methods of fixation have been used, including vicryl tape, PDS loops and the use of a hook plate. Many of these operative methods require a second operation to remove the plates and/or screws, and are associated with a failure rate of up to 30%. The ‘Surgilig’ was designed as a method of revision for failed Weaver-Dunn procedures. However this study evaluates its use in the primary operation. We prospectively followed up the Modified Weaver Dunn procedures using surgilig. The post-operative x-rays were reviewed at six weeks, 3 months and then 6 months when the patients were discharged to assess the radiological success of the procedure. We have performed this procedure in 11 patients. Of the eight patients that have reached the six month postoperative time so far, at which they would be discharged from clinic follow-up, none have had radiological failure of the fixation. One patient even had weight-bearing x-rays taken at 6 weeks, with no detrimental effect. Even though a small study, the initial results for primary fixation of acromioclavicular joint disruption with surgilig are extremely encouraging. The study suggests that surgilig should continue to be used in its current role. As patient numbers increase, a follow-up study should be conducted to evaluate these preliminary findings