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

Abstract

Background The modified Dunn procedure, which is an open subcapital realignment through a surgical dislocation approach, has gained popularity for the treatment of unstable slipped capital femoral epiphysis (SCFE). Intraoperative monitoring of the femoral head perfusion has been recommended as a method of predicting osteonecrosis; however, the accuracy of this assessment has not been well documented. Questions/purposes We asked (1) whether intraoperative assessment of femoral head perfusion would help identify hips at risk of developing osteonecrosis; (2) whether one of the four methods of assessment of femoral head perfusion is more accurate (highest area under the curve) at identifying hips at risk of osteonecrosis; and (3) whether specific clinical features would be associated with osteonecrosis occurrence after a modified Dunn procedure for unstable SCFE. Methods Between 2007 and 2014, we performed 29 modified Dunn procedures for unstable SCFE (16 boys, 11 girls; median age, 13 years; range, 8-17 years); two were lost to followup before 1 year. During this period, six patients with unstable SCFE were treated by other procedures. All patients undergoing modified Dunn underwent assessment of epiphyseal perfusion by the presence of active bleeding and/or by intracranial pressure (ICP) monitoring. In the initial five patients perfusion was recorded once, either before dissection of the retinacular flap or after fixation by one of the two methods. In the remaining 22 patients (81%), perfusion was systematically assessed before dissection of the retinacular flap and after fixation by both methods. Minimum followup was 1 year (median, 2.5 years; range, 1-8 years) because osteonecrosis typically develops within the first year after surgery. Patients were assessed for osteonecrosis by the presence of femoral head collapse at radiographs obtained every 3 months during the first year after surgery. Seven (26%) of the 27 patients developed Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research 1 neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDAapproval status, of any drug or device prior to clinical use. Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. This work was performed at Children's Hospital Colorado, Aurora, CO, USA. osteonecrosis. Mea...

Intraoperative Monitoring of Epiphyseal Perfusion in Slipped Capital Femoral Epiphysis

“…To date, none of our patients, including some with 5 years of follow-up and those in our study 3 with a minimum follow-up of 2 years, have developed osteonecrosis. Recent studies have validated the use of the ICP probe in monitoring for epiphyseal perfusion in patients undergoing a modified Dunn procedure for unstable SCFE, finding it an effective technique for identifying patients who may go on to develop osteonecrosis 4,5 .…”

Intraoperative assessment of femoral head perfusion during surgical hip dislocation for slipped capital femoral epiphysis

“…The intraoperative assessment of femoral head perfusion is becoming increasingly common when treating SCFEs [ 31 , 32 ]. Many studies have now published results suggesting that this may be a more accurate and easier way to predict the development of AVN rather than previously described methods such as MRI, bone scan or angiography [ 14 , 19 ]. It also has the benefit of real-time adjustment of ostectomy and reduction position to ensure adequate head perfusion is maintained.…”

“…The methods of assessing femoral head perfusion that have been described are evaluation of bleeding by creating a drill hole [ 16 , 29 , 33 ], the use of Laser Doppler Flowmetry [ 17 , 20 ] and intracranial pressure monitoring (ICP) [ 14 , 19 ]. Assessing bleeding via a drill hole is a simple way to assess femoral head perfusion but can only be done with open surgeries.…”

“…Intraoperative assessment of femoral head perfusion may allow for real-time adjustment of ostectomy and reduction in an attempt to restore perfusion and therefore decrease the risk of development of AVN. Multiple techniques of intraoperative assessment of femoral head perfusion have been described in the literature [ 14–20 ].…”

Outcomes after slipped capital femoral epiphysis: A population-based study with three-year follow-up

“…They showed that blood flow was restored after reduction for four of six patients who did not have arterial flow to the femoral head on the preoperative angiogram. Novais et al 37 used different techniques in the perioperative setting for 29 patients with unstable SCFE who underwent a capital realignment procedure to evaluate the restoration of blood flow to the femoral head during the operation. They concluded that assessment of femoral head blood perfusion can be used as a predictor of the later development of AVN.…”