We present the results of a prospective study about twenty-nine patients (thirty-two hips) with unstable slipped capital femoral epiphysis (SCFE), which were treated by indirect reduction and internal fixation of the epi- and metaphysis with 3–4 Kirschner-wires between 1990 – 1999.

Methods: The 29 patients with a mean age of 12,9 years were clinically and radiologically evaluated after a mean follow-up of 3 years applying the score of Heymann and Herndon and by different roentgenological parameters (CCD-angle, femoral head diameter, length of the femoral neck and sphericity of the femoral head). Compared to the uninvolved side in unilateral case, which all had prophylactic pinning, all patients showed overall a good subjective and objective outcome. The average slip angle of all 29 unstable SCFE patients (32 hips) was 31° with 19 (59,4%) mild SCFE (< 30°), 7 (21,9%) moderate forms (30–50°) and 6 (18,8%) severe slips (> 50°).

Results: According to the classification of Heyman and Herndon we had 18 excellent (62,1%), 9 good (31,1%), 1 fair (3,4%) and 1 poor (3,4%) results. None of the patients developed chondrolysis, but AVN occurred in one patient with complete and in one patient with partial involvement of the femoral head. The mean CCD-angle at the follow-up after skeletal maturity of the affected side was 133,3° in comparison to 135,9° of the non affected hips, indicating only a slight increase of varus position of the femoral neck of at average 2,6°. The mean length of the femoral neck of the affected hips was 64,5 mm in comparison to 70,8 mm of the not affected hips, thus a average difference of 6,3 mm. The neck/shaft-ratio between the affected and the not affected side was 0,88 (0,78 – 1,0). The mean femoral head diameter of the affected hips was 57,1 mm in comparison to 55,4 mm of the non affected hips. The radius quotient (RQ), measuring the relation of the femoral heads between the affected and the not affected hip was at average 103% (min 100 %, max. 114%). The sphericity according to Mose of the 58 hips (29 patients) treated by pinning with K-wires was normal (< 2mm) in 89,7% (52 hips), mild I°-aspheric (2–3mm) in 3,4% (2 hips), moderate II°-aspheric (3–4mm) in 3,4% (2 hips) and severe III°-aspheric (> 4mm) in 3,4% (2 hips).

Conclusion: As a standard in our institution we recommend the simultaneous transfixation of the epi- and metaphysis with Kirschner-wires in patients with unstable SCFE as therapeutic method for the involved as well as prophylactic for the uninvolved femoral epiphysis. Implants should not be placed in the anterosuperior quadrant of the femoral head and correct implant position has to be documented by the withdrawl maneouver using image intensifier during surgery. With this technique the slip could efficiently be stabilized, further slippage or any progression could be prevented and remodeling of the joint led to an optimal sphericity and improved femoral neck length at the end of growth, thus improving hip function. The rate of severe complications like AVN and chondrolysis was low in our prospective series (6,8% respectively 0%) compared to other series with different implants (screws, nails). There were no complications like implant failure or problems with hardware removal.