Short Term Outcome of Varus Derotation Osteotomy in Late Presenting Perthes Disease.

Background: Untreated Perthes disease can lead to osteoarthritis by the fourth decade. The treatment is conservative for children <6 years, operative within the age group of 6-9 years. Late onset Perthes, older than 9 years or more, are notorious with the aggressive course with poor outcome. However, literature do not come to a consensus between conservative and operative management. This study evaluates the clinical and radiological outcome of varus derotation osteotomy (VDRO) in Perthes disease presenting late with age 8 years or more.

Materials and Methods: 15 children (13 males and 2 females) with the mean age of 9.4 years belonging to modified Elizabethtown classification Stage IB, IIA, IIB treated with open wedge VDRO between 2008 and 2014 were included in this study. Seven patients (46.67%) were of >10 years of age at presentation. All patients had limitation of abduction and internal rotation. Eight patients (53.33%) had pain at the hip and 12 patients (80%) had limp. Mean time between diagnosis and corrective surgery was 3 weeks.

Results: The evaluation was done using caput index (CI) and epiphyseal quotient (EQ) and articulotrochanteric distance radiologically, range of motion and Harris Hip Score for clinical outcome. All the measurements were carried out on pre- and postoperative X-rays after 3 years followup and compared with the contralateral normal hip. After a mean followup period of 3.4 years, we noted the statistically significant difference between pre- and postoperative values. We noted that all (100%) children in Stage IB, IIA and 50% children in Stage IIB achieved satisfactory results. There was a significant change ( P = 0.000) in CI among all the patients after surgery. The final EQ after 3 years of VDRO was 0.606 and was significant ( P = 0.0000).

Conclusion: In our opinion, based on the encouraging short term radiological and clinical outcomes, VDRO may be regarded as a treatment procedure for late presenting Perthes disease in stage IB, IIA, IIB.