SINGLE CANNULATED SCREW FIXATION VERSUS MULTIPLE PIN FIXATION OR OSTEOTOMY IN THE MANAGEMENT OF SLIPPED UPPER FEMORAL EPIPHYSIS – A COMPARATIVE STUDY

Abstract

Single screw fixation for the management of slipped upper femoral epiphysis (SUFE) was introduced in 1984 and has been reported to have less chondrolysis and avascular necrosis (AVN) than previous methods using multiple pin fixation or osteotomy (Ward 1992). Two groups of patients were investigated. The first group of 55 hips (44 patients) were treated over a 27 year period (1963–1989). Forty four hips were treated with multiple pins and 11 hips with primary intra- or extracapsular osteotomy. These patients were followed up for an average of 8 years (3–27yrs). The second group of 88 hips (69 patients) were treated over a 6 year period (1999–2004). All were treated with single screw fixation and followed up for at least one year.

The duration and severity of slip were found to be similar for both groups. In the second group 16 hips (20%) were unstable (unable to walk even with crutches). Instability had not been coined as a term in the first group. All serial radiographs were retrospectively reviewed for AVN and chondrolysis and correlated with clinical findings. In the first group AVN occurred in 8 hips (14.5%). Five (9%) were due to osteotomies, two (3.5%) due to manipulation and one (2%) due to pinning in the superior quadrant. Chondrolysis occurred in 14 hips (25%); eight (14%) at presentation and six (11%) due to persistent pin penetration. In the second group AVN occurred in two hips (2%). Both were unstable. Two of 16 unstable hips (12.5%) developed AVN. Chondrolysis occurred in 6 hips (7%); four (4.5%) at presentation and 2 (2.5%) due to persistent pin penetration.

The authors conclude that single screw fixation is a safer technique than multiple pin fixation or osteotomy. AVN only occurred in unstable slips. Chondrolysis due to pin penetration is significantly reduced.