The Bone & Joint Journal provides the latest evidence to guide the clinical practice of orthopaedic surgeons. The benefits of one intervention compared with another are presented using outcome measures; some may be specific to a limb or joint and some are more general health-related quality of life measures. Readers will be familiar with many of these outcome measures and will be able to judge the relative benefits of different interventions when measured using the same outcome tool; for example, different treatments for pain in the knee measured using a particular knee score. But, how should readers compare outcomes between different clinical areas using different outcome measures? This article explores the use of standardised effect sizes.

Cite this article: Bone Joint J 2014;96-B:853–4.

The importance for observing the intention-to-treat approach in clinical studies is explained.

Cite this article: Bone Joint J 2013;95-B:1443–4.

Richard Carey Smith is an orthopaedic oncology surgeon with fellowship training in the UK, USA, Australia and Canada, and has worked in Zambia, Zimbabwe and Papa New Guinea. David Wood is head of the University Department of Orthopaedics in Perth, Western Australia. He did his masters in Africa, and first experienced Papa New Guinea on his medical elective, starting a lifelong commitment to medical aid work there.

To determine the natural history of dislocation of the hip in cerebral palsy, and to evolve methods to predict dislocation, the notes and radiographs of 462 patients with cerebral palsy were reviewed. Dislocation occurred in 10% of patients by progressive migration and subluxation of the proximal femur in the presence of acetabular dysplasia. Statistical analysis identified the radiographic features that helped to predict dislocation. Measurement of acetabular index, by a method that allows for rotation of the acetabulum, was the most powerful single predictor. Measurement of this index at two and four years of age could identify patients who would dislocate unless effective treatment was undertaken, those at risk of dislocation only if scoliosis developed, and those who would not dislocate. On the basis of this method of screening for dislocation, a logical system of surgical prophylaxis is proposed.

Seven patients treated in infancy by a lumbar theco-peritoneal shunt for idiopathic communicating hydrocephalus presented later in childhood after developing a characteristic orthopaedic syndrome. This included a severe, rigid and progressive lumbar hyperlordosis, severe bilateral restriction of straight leg raising and abnormalities of stance and gait. Four of the patients, who had severe hyperlordotic curves of over 90 degrees, required operations to correct their extreme deformity. The recommended method of correction is a three-stage procedure: first, anterior wedge resection osteotomies at several levels in the lumbar spine, then a period of "90-90" femoral traction, and finally a posterior fusion and stabilisation using Harrington instrumentation. The results were good, with few complications.

Simultaneous dislocation of the elbow and the proximal radio-ulnar joint is rare. Two children with this uncommon injury are reported. One child had a transverse divergent dislocation that was treated successfully by closed reduction. The other had a convergent dislocation (or translocation of the radius and ulna) which needed open reduction. Convergent dislocation is even rarer than transverse divergent dislocation, and this is believed to be the first time it has been reported.

Synovial chondromatosis is a rare metaplastic condition affecting major synovial joints. It is extremely rare in childhood. The two children reported here are believed to be the youngest patients with this condition affecting the knee to have been described in the literature.