Blount's epiphyseal stapling can be recommended as a safe procedure with predictably good results in idiopathic angular deformities of the leg and leg length difference caused by overgrowth.

Treatment of slipped capital femoral epiphysis (SCFE) is still controversial. Agreement has not yet been reached on the appropriate time to perform surgery, the necessity of repositioning manoeuvres, the type of implants for stabilisation, or the need for prophylactic treatment of the contralateral side. In this retrospective study, we present 29 patients with unstable (acute and acute-on-chronic) SCFE treated by internal fixation of the epiphysis with three or four Kirschner wires both therapeutically on the affected side and prophylactically on the not (yet) affected side. After hardware removal and mean follow-up of 3.5 years, radiological and clinical examination of hip function was carried out. X-ray in two planes showed no incidence of any slip progression. Applying the score used by Heyman and Herndon, 18 results (62.1%) were classified as excellent, nine (31.1%) as good, one (3.4%) as fair, and one (3.4%) as poor. The rate of severe complications such as chondrolysis and avascular necrosis of the femoral head was low in our series (0% and 6.8%, respectively). This form of therapeutic management shows good clinical results with low complication rates. The slip can be efficiently stabilised, progression is reliably prevented, and remodelling of the joint gives the patient good overall hip function. We see no indication for emergency surgery.

Treatment of slipped capital femoral epiphysis is still controversial with regard to the implants used for stabilization and the need for prophylactic treatment of the contralateral, unaffected, side. The objective of this study was to ascertain whether prophylactic transfixation of the epiphysis with Kirschner wires in patients with unstable slipped capital femoral epiphysis resulted in significant disturbance of the growth plate and impairment of further growth of the femoral neck and head. Between 1990 and 1999, 29 patients with unstable slipped capital femoral epiphysis were simultaneously treated with internal fixation of the epiphysis and metaphysis with 3-4 Kirschner wires on the affected and the not (yet) affected side. After a mean follow-up of 3.5 years, we evaluated the hip joints radiologically, analysing different roentgenological parameters (CCD angle, femoral head diameter, length of the femoral neck and sphericity of the femoral head). CCD angle, femoral head diameter and length of the femoral neck showed statistically significant (P<0.001, Student's t-test) differences between the affected and unaffected, but prophylactically pinned, sides. Asphericity of the femoral head was found in six cases only on the affected side, whereas all hips, which were operated prophylactically, showed spherical femoral heads at follow-up (P<0.02, Pearson's chi test). These results indicate that the slip itself may cause impairment of the femoral growth plate in patients with unstable slipped capital femoral epiphysis and not stabilization with Kirschner wires. Compared with other series from the literature using different implants (screws, nails), prophylactic transfixation of the epiphysis and metaphysis with Kirschner wires is less compromising to the growth plate on the not (yet) affected side.

A lot of new implant devices for spine surgery are coming onto the market, in which vertebral screws play a fundamental role. The new screws developed for surgery of spine deformities have to be compared to established systems. A biomechanical in vitro study was designed to assess the bone-screw interface fixation strength of seven different screws used for correction of scoliosis in spine surgery. The objectives of the current study were twofold: (1) to evaluate the initial strength at the bone-screw interface of newly developed vertebral screws (Universal Spine System II) compared to established systems (product comparison) and (2) to evaluate the influence of screw design, screw diameter, screw length and bone mineral density on pullout strength. Fifty-six calf vertebral bodies were instrumented with seven different screws (USS II anterior 8.0 mm, USS II posterior 6.2 mm, KASS 6.25 mm, USS II anterior 6.2 mm, USS II posterior 5.2 mm, USS 6.0 mm, USS 5.0 mm). Bone mineral density (BMD) was determined by quantitative computed tomography (QCT). Failure in axial pullout was tested using a displacement-controlled universal test machine. USS II anterior 8.0 mm showed higher pullout strength than all other screws. The difference constituted a tendency (P = 0.108) when compared to USS II posterior 6.2 mm (+19%) and was significant in comparison to the other screws (+30 to +55%, P < 0.002). USS II posterior 6.2 mm showed significantly higher pullout strength than USS 5.0 mm (+30%, P = 0.014). The other screws did not differ significantly in pullout strength. Pullout strength correlated significantly with BMD (P = 0.0015) and vertebral body width/screw length (P < 0.001). The newly developed screws for spine surgery (USS II) show higher pullout strength when compared to established systems. Screw design had no significant influence on pullout force in vertebral body screws, but outer diameter of the screw, screw length and BMD are good predictors of pullout resistance.

In view of the number of inadequate reductions in plaster casts, we recommend verifying the position of the hip joint by MRI. This MRI documentation should be established as a standard examination post-reduction.