Significantly lower femoral neck growth in screw fixation of the asymptomatic contralateral hip in unilateral slipped capital femoral epiphysis

Abstract

There is an ongoing debate on which fixation technique should be preferred for the prophylactic fixation of the asymptomatic contralateral hip in slipped capital femoral epiphysis (SCFE). In the case of Kirschner-wire (K-wire) fixation, there is a possibility of secondary loss of fixation because of longitudinal growth of the physis, whereas in screw fixation, physeal growth of the femoral neck might be impaired. The aim of this matched-pair study was to compare the longitudinal growth of the femoral neck in screw fixation versus K-wire fixation of the asymptomatic contralateral hip in SCFE. All 18 patients (female:male=3:15), who had undergone screw fixation of the asymptomatic contralateral hip between 9/2001 and 9/2011, were matched according to age, bone age, sex, and time to follow-up to another 18 patients with K-wire fixation. The length of the femoral neck of the contralateral hip was measured in parallel to either screw or K-wire from the apex of the femoral head to the opposite cortical bone. The ratio of the femoral neck length measured directly after surgery and on follow-up was defined as femoral neck growth. There was no significant difference between groups with respect to age, modified Oxford Bone age score, and time to follow-up. We found a significant difference in femoral neck growth between patients with screw fixation (5.5 ± 4.3%) compared with K-wire fixation (8.9 ± 5.7%, P = 0.048 matched Wilcoxon test). The difference in femoral neck growth of patients with K-wire or screw fixation of the contralateral asymptomatic hip in SCFE was small, but statistically significant. Thus, despite high rates of secondary loss of fixation, K-wire fixation should still be considered, especially in very young patients.

Telescoping screw fixation compared to traditional in situ screw fixation for slipped capital femoral epiphysis: clinical, radiographic and patient-reported outcomes

“…Smooth Kirschner wires have also been attempted, although these are less popular due to concerns for loss of fixation and pin migration. A study comparing the use of K-wires to standard screw fixation for prophylaxis noted a significant difference in neck length (8.9 mm for K-wires compared to 5.5 mm for standard screws) [26]. Sailhan et al .…”

Factors Affecting Outcomes of Slipped Capital Femoral Epiphysis

“…Multiple (two to three) smooth stainless steel pins through the growth plate, driven up to 2 mm from the subchondral bone of the capital femoral epiphysis, are also a safe option to stabilize the slip ( Figure 2). Compared to the typical cannulated screw stabilization, multiple pins may spare the remaining growth potential of the femoral neck physis [4,5].…”

“…Promoting physeal arrest was the main goal of SCFE treatment in the past in order to avoid slip recurrence due to the continued growth of the femoral neck [1,4]. Recent studies about growth and remodeling of the femoral neck strongly suggest that SCFE treatment should take advantage of the remaining growth of the femoral neck physis, in order to prevent complications such as femoroacetabular impingement and limb length discrepancy [1,4,5]. This is crucial in relatively younger patients [5].…”

“…SCFE is a disease of the growing skeleton. It is expected that the remaining growth of the hip will be affected, either primarily, by the process that caused the slip, or secondarily, by the surgical technique or by the delay of treatment [3][4][5][6][7][8][9][10].…”

Is prophylactic fixation preferable to active surveillance of the unaffected contralateral hip in unilateral slipped capital femoral epiphysis?- A Systematic Review

“…Fixation of head with threads spanning the physis prevents further growth at the neck [27]. This can lead to a short neck, high riding trochanter and possibility of late secondary osteoarthritis [27]. To avoid this, some surgeons use non threaded pins or K-wires [23,24].…”