Results of percutaneous musculotendinous release in children with hip dysplasia secondary to cerebral palsy aged under six years Dr. Peter Bernius Centre for Pediatric und Neuroorthopedic Surgery - Schön Clinic Munich Harlaching Background Hip displacement is common in cerebral palsy (1). Badly involved children are more frequently involved (2). Beside other factors elevated muscle tonus can lead to hip dysplasia with subsequent luxation in cerebral palsy. Especially hip adducting, hip flexing and medial knee bending muscles play a main role in developing and maintaining a hip dislocation (3). Due to the maturation potential of the hip, in children younger than 6 years conservative methods like botulinum toxin therapy, physiotherapy or special orthoses may improve centering of the hip (5, 6, 7). But hips with a Reimers migration index (RMI) more than 40% require surgical treatment (8). In children with cerebral palsy we prefer percutaneous muscle release because we consider it a minimal invasive method with low risks and good results. Therefore we studied the influence of this method on the RMI. Method We retrospectively examined 43 patients suffering from cerebral palsy and having increased hip migration from 2 to 6 years (mean 4.04 years) and 55 hips. The severity of cerebral palsy was classified according to gross motor function classification system (GMFCS). Patient's GMFCS ranged from 3 to 5. Inclusion criteria were children aged under six years with an RMI more than 25%. RMI was measured in X-rays pre- and postoperatively in a follow up of 11.9 months (0-36 months). Depending on clinical examination of the patients being under anaesthetic immediately before operation, we performed percutaneous release of hip adducting, superficial hip flexing or medial knee bending muscles or combinations of these. Results Altogether RMI could be improved from 42.5% to 37.8%. Concerning hips with a RMI from 25% to 39% (group A, n= 22) RMI could be improved only slightly (from 30.8% to 29.8%), whereas hips with a RMI over 40% (group B, n=33) RMI could be improved from 50.2% to 43.1%. In group A the RMI worsened in 5 hips (22.7%), stayed equal in 11 hips (50%) and improved in 6 hips (27.3%). In group B the RMI worsened in 4 hips (12.1%), stayed equal in 12 hips (36.4%) and improved in 17 hips (51.5%). In GMFCS 3 patients, RMI could be improved from 37.1% to 33.6%, in GMFCS 4 patients from 42.1% to 33.8% and in GMFCS 5 patients from 46.9% to 45.8%. Conclusion Soft tissue balancing is an efficient possibility to avoid further hip migration in children with cerebral palsy aged under 6 years. Although operative hip reconstruction might be necessary in future, early percutaneous muscle release can reach a better situation for further reconstructive surgery. References 1. Cornell MS The hip in cerebral palsy. Dev Med Child Neurol 1995;37:3–18 2. Soo B, Howard JJ, Boyd RN, et al. Hip displacement in cerebral palsy. J Bone Joint Surg Am 2006;88: 121-129 3. Flynn et al. Management of hip disorders in patients with cerebral palsy. J Am Acad Orthop Surg. 2002;10:198– 209 4. Terjesen T. Development of the hip joints in unoperated children with cerebral palsy: a radiographic study of 76 patients. Acta Orthop. 2006;77:125–131 5. Jung NH1, Heinen F, Westhoff B, Doederlein L, Reissig A, Berweck S, Linder-Lucht M, Schandelmaier S, Mall V Hip lateralisation in children with bilateral spastic cerebral palsy treated with botulinum toxin type A: a 2-year follow-up Neuropediatrics. 2011 Feb;42(1):18-23 6. Portinaro N, Panou A, Gagliano N, Pelillo F D.D.S.H.: developmental dysplasia of the spastic hip: strategies of management in cerebral palsy. A new suggestive algorithm. Hip Int. 2009 Jan-Mar;19 Suppl 6:S69-74. 7. Spiegel DA, Flynn JM Evaluation and treatment of hip dysplasia in cerebral palsy Orthop Clin North Am. 2006 Apr; 37(2):185-96 8. Hägglund G, Andersson S, Düppe H, Lauge-Pedersen H, Nordmark E, Westbom L Prevention of severe contractures might replace multilevel surgery in cerebral palsy: results of a population-based health care programme and new techniques to reduce spasticity. J Pediatr Orthop B. 2005 Jul;14(4):269-73 Pict. 1: Development of RMI after percutaneous musculotendinous release (green), natural history (4) (red). Pict. 2 a-c: 2 year old girl: Radiographs of pelvis pre (a), 1 (b) and 2 years post percutaneous musculotendinous release . Recentration of both hip joints and slowly improving AC angle. Contact information: Dr. Peter Bernius, Zentrum für Kinder- und Neuroorthopädie, Schön Klinik München Harlaching, Harlachinger Str. 51, 81547 München, pbernius@schoen-kliniken.de