Table 4.
Summary of the results of modified Dunn procedure in different studies
| Article | Type of study | Level of evidence | Number of hips | Follow-up period (mean ± SD or range) | Stable Vs unstable SCFE | Affected side Rt/Lt |
Age (Mean ± SD or range) |
Sex Male/Female |
Number of cases with AVN (stable/ unstable SCFE) |
Other complications | Conclusions/recommendations |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Abdelazeem, 2016 [8] | Prospective Case series | IV | 32 | 31months (12–40) | 32/0 | 21/11 | 14.3 ± 1.8 years | 26/5 | 1/0 | NR | Modified Dunn Procedure is a safe treatment option in stable SCFE with high slip angle |
| Agashe 2021 [30] | Retrospective case series | IV | 30 | 25.36 months (13–60) | 19/11 | 16/14 | 13.05 ± 1.41 | 25/5 | 0/2 | 1 Hip subluxation | Modified Dunn procedure is the first treatment option for moderate and severe forms of SCFE |
| Alves, 2012 [26] | Retrospective case series | IV | 12 | NR | 0/12 | NR | 12.15 years | 6/6 | 0/6 | NR | Modified Dunn Carries a higher risk for AVN development compared to closed reduction and percutaneous pinning |
| Birke 2021 [21] | Retrospective case series | IV | 178 | 2.7 years (1–9.2) | 107/71 | 78/94 | 13.5 years (9.5–17.5) | 96/76 | 5/15 |
7 Hip dislocations 2 FAI 4 peroneal nerve palsy 1 DVT 1 sciatic neuropathy 4 superficial wound infection |
They recommended using the Modified Dunn procedure in stable SCFE combined with intra-operative monitoring. It provided equivocal results regarding AVN development in unstable cases. |
| Davis 2019 [22] | Retrospective case series | IV | 48 | 27.9 months | 17/31 | NR | 12.5 years ± 13.8 | NR | 5/2 |
3 hip subluxation or dislocation 4 heterotopic ossifications 4 hardware failure |
The procedure carries a higher risk for AVN and hip instability in patients with stable SCFE with inferior restoration of the proximal femoral anatomic parameters. It should be used with caution in patients with chronic, stable SCFE |
| Fournier, 2022 [38] | Retrospective case series | IV | 41 | 2–4 years | 0/41 | NR | 11.5–14.9 years | 17/24 | 0/8 |
2 chondrolysis 2 FAI |
Cuneiform osteotomy has equal result to modified Dunn in the treatment of severe unstable SCFE |
| Gabana, 2022 [20] | Retrospective case series | IV | 19 | NR | NR | 12/7 | 11.9 years ± 1.8 | 8/11 | 7 (NR) |
1 hardware failure 6 Secondary FAI 1 hip instability |
The procedure carries a high risk for the development of AVN in cases with severe SCFE. No specific risk factor was associated with the development of AVN. |
| Galletta, 2021 [23] | Retrospective cohort | III | 81 | 5.7 years ± 3.3 | NR | 35/46 | 13.6 years ± 1.9 | 59/17 | 16 (NR) |
2 hardware failure 9 conversions to THA 2 trochanteric non-union |
Modified Dunn procedure carries an equal risk of AVN compared to in situ pinning in moderate and severe stable slips. |
| Jackson, 2018 [40] | prospective case series | IV | 9 | 22 months | 0/9 | NR | 12.2 years (11 − 9) | 5/4 | 2(unstable) | (NR) |
Super-selective medial circumflex femoral artery angiography was performed pre-and post-operatively to assess femoral heal perfusion in cases with unstable SCFE, supplemented by an intra-operative evaluation of perfusion using an intracranial pressure Monitor. There was no procedure-induced loss of perfusion with six cases having pre-operative blood flow to the femoral head. |
| Lerch, 2019 [14] | Retrospective case series | IV | 46 | 9 months (4–20) | 70/30 | 20/80 | 13 years ± 2 | 65/35 | 2 (NR) |
1 hardware failure 3 Secondary FAI |
The procedure carries an acceptable complication rate for cases with severe SCFE except for the development of FAI which might need further surgical interventions |
| Leunig, 2007 [5] | Retrospective case series | IV | 30 | 55 months (24–96( | NR | 7/23 | 13 years (10–17) | NR | 0 | 2 hardware failure | The original case series described the procedure. They followed the patient for an average of 55 months, with no evidence of AVN. |
| Madan, 2013 [41] | Prospective case series | IV | 28 | 38.6 months (24 to 84) | 11/17 | NR | 12.9 years (10 to 20) | 14/14 | 0/4 | No other complications | In this early case series, the authors had only 2 cases of AVN. No other complications were reported, and the procedure was considered as a safe option for all types of SCFE. |
| Masquijo 2019 [31] | Retrospective Case series | IV | 21 | 40.4 months (12–84) | 15/6 | 13/8 | 12 years (10–16) | 10/10 | 2/8 |
1 superficial infection 1 conversion to THA |
This was a multicenter study where again the authors acknowledged the technical complexity and high learning curve of the procedure, which accounted for their high complication rate. |
| Novais, 2015 [39] | Retrospective cohort study | III | 15 | 2.5 years (1–6) | 15/0 | NR | NR | NR | 1/0 |
1 hardware failure 1 conversion to THA |
The procedure has a similar complication rate and better femoral morphologic features compared to in situ pinning in stable severe SCFE. |
| Novais, 2019 [28] | Retrospective cohort study | III | 27 | 2.4 years (1.8–3.1) | 0/27 | NR | 12.6 years (11.8–13.5) | 15/12 | 7 |
1 hardware failure 4 conversions to THA |
Comparing the procedure to in situ pinning for cases of unstable SCFE, it shows better clinical and radiographic outcomes with a similar proportion of osteonecrosis and unplanned re-operations |
| Persinger, 2018 [24] | Retrospective case series | IV | 31 | 29.3 months (12–82) | 0/31 | 11/20 | 12.37 (8.75–14.8) | 15/15 | 2 | 1 hardware failure | The study was a single surgeon study, where 31 cases of unstable SCFE were recruited. It concluded that the modified Dunn procedure was a safe and effective procedure for unstable SCFE with acceptable complication rate. |
| Sankar, 2013 [18] | Retrospective case series | IV | 27 | 22.3 months ± 12.48 | 0/27 | 9/18 | 12.6 years (9.7–16) | 17/10 | 7 |
4 hardware failure 1 conversion to THA |
This was the first reported multicenter study which included also included patients with unstable SCFE only. It again demonstrated the superiority of the procedure in restoring the anatomical parameters, but with a considerable risk of complications including AVN (26%) |
|
Sikora-Klak, 2019 [29] |
Retrospective cohort | III | 14 | 29 months ± 8.9 | 14/0 | NR | 13.1 years ± 1.9 | 8/6 | 4 |
2 hardware failure 2 conversions to THA |
The authors of this study compared two procedures: the modified Dunn procedure and the tri-planar femoral osteotomy. They advised against the use of the modified Dunn procedure in stable cases as all their 4 cases who developed AVN were in the modified Dunn group. In contrast, no patients in the tri-planar osteotomy group developed AVN, despite its technical difficulty. |
| Trisolino, 2018 [37] | Retrospective case series | IV | 29 | 4.3 years ± 2.6 | 29/0 | 12/17 | 13.9 years ± 2.3 | 22/7 | 3 | 2 conversions to THA | The study compared the modified Dunn procedure to in situ fixation only in severe SCFE. Three patients developed AVN, while none developed AVN in the in-situ group. This raised suspicions against the procedure’s safety in severe SCFE; however, overall, both groups had comparable re-operation rates for different reasons. |
| Upasani, 2014 [19] | Retrospective case series | IV | 43 | 2.6 years | 17/26 | 10/7 | 12 years ± 1.7 | 18/25 | 10 (NR) | NR | The study was a single-centre experience that involved consecutive recruitment of patients with all forms of SCFE. The study revealed an inverse relationship between surgeon volume and outcomes. So, they modified their practice by having an experienced surgeon present at each procedure. Additionally, only patients with acute severe (> 50 degrees) epiphyseal displacement with mild chronic remodelling of the metaphysis who can be treated within 24 h of the slip were offered the modified Dunn technique. |
| Upasani, 2017 [34] | Retrospective case series | IV | 17 | 2 years | 10/7 | NR | 13 years | 10/7 | 14 (NR) |
3 conversions to THA 8 hip instability |
The main aim of the study was to investigate iatrogenic hip instability after the procedure. Seventeen patients developed post-operative anterior hip instability. The researchers proposed that the patients might benefit from a period of bracing using either an abduction brace or broomstick cast to reduce the chances of future hip instability. |
| Ziebarth 2009 [17] | Retrospective case series | IV | 40 | 3.8 years (1–8) | 28/12 | 12/28 | 12.6 years (9–18) | 17/23 | 0 |
4 Heterotopic ossifications 1 FAI 3 hardware failure |
In this case series, no patient developed AVN. They supported the procedure for moderate and severe forms of SCFE. |
| Our Study | Prospective case series | IV | 36 | 49.28 months ± 23.10 (range 24–118 months). | 24/12 | 14/22 | 14 ± 1.19 | 29/7 | 3/2 |
1 chondrolysis (2.8%), one (2.8%) had hardware penetration (K-wire) into the hip, which was surgically removed |
the modified Dunn procedure is a safe option for treating moderate to severe SCFE. It provides superior femoral head realignment and patient-reported outcomes. It can be safely performed by experienced surgeons with accepted complication rates, including AVN. |
SCFE: Slipped Capital Femoral epiphysis, AVN: Avascular Necrosis, NR: Not Reported, FAI: Femoroacetabular Impingement, DVT: Deep Venous Thrombosis, THA: Total Hip Arthroplasty