Adolescent slipped capital femoral epiphysis treated by a modified Dunn osteotomy with surgical hip dislocation

Abstract

Between June 2001 and November 2008 a modified Dunn osteotomy with a surgical hip dislocation was performed in 30 hips in 28 patients with slipped capital femoral epiphysis. Complications and clinical and radiological outcomes after a mean follow-up of 3.8 years (1.0 to 8.5) were documented. Subjective outcome was assessed using the Harris hip score and the Western Ontario and McMaster Universities osteoarthritis index questionnaire. Anatomical or near-anatomical reduction was achieved in all cases. The epiphysis in one hip showed no perfusion intra-operatively and developed avascular necrosis. There was an excellent outcome in 28 hips. Failure of the implants with a need for revision surgery occurred in four hips. Anatomical reduction can be achieved by this technique, with a low risk of avascular necrosis. Cautious follow-up is necessary in order to avoid implant failure.

Is Assessment of Femoral Head Perfusion During Modified Dunn for Unstable Slipped Capital Femoral Epiphysis an Accurate Indicator of Osteonecrosis?

“…It is unclear, however, whether revascularization was related to the integrity of the retinacular vessels or if it may have happened through a transphyseal mechanism. Contrary to previous studies [9,18,30], we found three patients with an ICP waveform before dissection and after fixation who later developed osteonecrosis. These represent examples of a false-negative test result.…”

“…One of the benefits of the subcapital realignment through the surgical dislocation approach (modified Dunn procedure) is visualization and protection of the vascular retinaculum and direct assessment of perfusion of the femoral head during surgery. Femoral head perfusion may be assessed by evaluating bleeding after creating a 2-mm drill hole [9,24,30,31], by laser-Doppler flowmetry [9,30], and/or by intracranial pressure probe monitoring [24]. Assessment of perfusion during surgery may allow for adjustments of positioning the femoral head if blood flow decreases after the femoral head is reduced.…”

Surgical Hip Dislocation for Treatment of Slipped Capital Femoral Epiphysis

“…. In K. Ziebarth et al [22] study postoperative Alpha angle ranged from 27 0 to 60 0 with mean of 40.6 0 , in H. HUBER et al [25] study postoperative Alpha angle ranged from 27 0 to 77 0 with mean of 41.4 0 , in T.Slongo et al [24] study postoperative Alpha angle ranged from 24 0 to 53 0 with mean of 38 0 . In Novais et al [26] study postoperative Alpha angle ranged from 40 0 to 51 0 with mean of 44 0 (Table 4).…”

“…In K. Ziebarth et al [22] study 23 patients were classified as moderate and 12 patients were severe, in H. HUBER et al [25] study 3 patients were classified as mild, 17 were moderate, and 10 patients were severe, in T.Slongo et al [24] study 6 patients were classified as mild, 8 were moderate, and 9 patients were severe. Novais et al [26] study 15 patients (100%) were severe.…”

Is the femoral head dead or alive before surgery of slipped capital femoral epiphysis? Interest of perfusion Magnetic Resonance Imaging

“…5,9,23 Some short series showed that modified Dunn procedure with femoral neck shortening and femoral head reduction and fixation seems to have a low rate of AVN with a good anatomic result. 32e34 In-situ fixation is considered as the most safe surgical technique regarding vascularization 30,32 but its functional result could be worse because of partial reduction of upper femoral deformity. Preoperative traction is not risky 8,35,36 or has no real benefit.…”