The mammalian growth plate is a complex structure which is essential for the elongation of long bones. However, an understanding of how the growth plate functions at the cellular level is lacking. This review, summarises the factors involved in growth-plate regulation, its failure and the consequence of injury. We also describe some of the cellular mechanisms which underpin the increase in volume of the growth-plate chondrocyte which is the major determinant of the rate and extent of bone lengthening. We show how living in situ chondrocytes can be imaged using 2-photon laser scanning microscopy to provide a quantitative analysis of their volume. This approach should give better understanding of the cellular control of bone growth in both healthy and failed growth plates.

Introduction & Discussion: From an experience of over 250 Salter osteotomies, 148 of which have been reviewed at skeletal maturity, certain technical tips merit discussion:-

Preoperative positioning and the incision

Psoas tenotomy, capsular exposure and the capsulotomy

Facilitation of the Gigli saw osteotomy

Sizing and procurement of the graft

Displacement and fixation of the osteotomy

Application of the hip spica

Some questions are worthy of debate:-

Can the osteotomy be safely combined with open reduction of the high dislocation?

Should the osteotomy be fixed before reducing the femoral head?

Are there alternatives to autogenous bone graft and K-wire fixation?

Is minimally invasive surgery an option?

Are the contraindications and alternatives to the Salter osteotomy fully appreciated?

Survivorship analysis of 215 medial displacement pelvic osteotomies undertaken for symptomatic, incongruent dysplasia of the hip since 1966 showed that four of every five hips had not required conversion to a total hip arthroplasty.

The radiological characteristics of 86 osteotomies were evaluated at a mean of 18 years (5 to 30) after surgery which was performed at the age of 15.9 ± 9.5 years. Revision was significantly (p < 0.05) more likely in those patients operated on after the age of 25 years. The centre-edge (CE) angle increased from 2.5 ± 13.9° before to 41.8 ± 15.0° immediately after operation. The increase in CE angle was maintained at later review (38.5 ± 16.5°). Even with severe dysplasia with a CE angle less than zero a substantial improvement in the cover of the femoral head was achieved, usually by medial shift of the lower pelvic fragment. However, the head was not invariably medialised by the osteotomy and lateral movement of the ilium was noted when the position of the joint was relatively medial before operation or when the hip was arthritic. In the longer term pelvic remodelling did not reverse the medialisation produced by the osteotomy, and the cover of the femoral head was maintained.

Purpose of study: The aim of this study was twofold. Firstly, to compare a subjective clinical with an objective biomechanical assessment of operated clubfeet, using the optical Dynamic Pedobarograph foot pressure system. Secondly, to develop the latter into a classification system for future prospective studies and to complement clinical evaluation of patients, especially those with relapse.

Methods and results: Sixteen patients (21 feet) were randomly selected from a pool of patients that had undergone clubfoot surgery. The operations were carried out by a single surgeon and consisted of a lateral-posteromedial peritalar release utilising the Cincinnati incision. Post-operatively, all feet were independently classified using a modified functional outcome scoring system. After completion of treatment, patients were referred to the Foot Pressure Analysis Clinic in Dundee where a novel method has been developed for the evaluation of clubfeet, using a static and dynamic foot pressure analysis system which provide both a graphical and analytical model for comparison. A three point grading scale was developed. The correlation between clinical and biomechanical outcomes in the 21 feet was calculated using Kendall’s tau rank test for non-parametric data. The t value was 0.3524, which was significant (p < 0.05).

Conclusion: There is a significant correlation between the above mentioned subjective and objective outcome measurements. Biomechanical assessment can complement, support or change the line of management after clubfoot surgery. This technique has not only proven to be objective but also clinically valuable and cost effective. A prospective study to refine this biomechanical classification into a reliable predictor of relapse in surgically corrected clubfeet is currently being considered

The term “skeletal skew” recognises the oblique positioning or slanting of two similar halves of the body. It is preferred to asymmetry which describes a disproportion between two quantities with no common measure. In 1982 69 babies with skeletal skew were described in relation to the abduction contracture which affects the hip and leg on which the body lies in persistent sidelying. The skeletal skew was evident at birth in 24 cases, but only became obvious at 4–6 months of age in the remaining 45 cases.

The adducted, uppermost hip looks spuriously dysplastic but the proximal femoral ossification centre is usually equal to the opposite side and the ultrasound scan is within normal limits. Associated skewing affects the skull (plagiocephaly) the neck (torticollis), thorax, pelvis and feet in a proportion of these squint babies. When the pelvic radiograph is assessed confusion is avoided if the ischial lower border is set horizontally; this corrects the apparent, increased acetabular inclination (angle) on the adducted side. The concomitant rotational artefact can be appreciated by reviewing differences in the widths of the iliac wings and obturator foramina, sacral-symphysial alignment and femoropelvic overlap.

Of the 45 cases with pronounced skeletal skew manifesting at 3–4 months of age, the oblique positioning corrected during early walking age, as shown by calculating the difference between the abduction arcs of the two hips. The plagiocephaly, with flattening of the brow on the upper side, may persist until skeletal maturity.

Follow up at 18 years was achieved in 41 of the 45 cases. There was one case of mild bilateral hip dysplasia and one case of a leg length discrepancy of 1.5 cm. In 40 cases the hips were normal clinically and radiographically although 5 had persistence of increased femoral anteversion. No splintage or stretching of the adducted hip had been undertaken during infancy and hence the great majority of cases with skeletal skew correct. Ultrasound assessment is advised in borderline cases for this relatively common condition which results in a referral rate of 5.3 per 1000 live births, compared to the Edinburgh neonatal splintage rate for hip instability of 3.8 per 1000 live births.

Somatosensory evoked potentials (SSEPs) measure the conduction pathways from the periphery to the brain and can demonstrate the site of neurological impairment in a variety of locomotor conditions.

SSEPs were studied in 44 children (64 feet) with surgically corrected club feet. Four children had unreproducible responses, 18 showed abnormal recordings and 22 showed normal responses. In a further 31 feet (21 children) subjected to motor electrophysiological tests, 16 (52%) were abnormal.

Overall, 44 of 95 feet (46%) showed abnormal SSEPs or motor electrophysiological tests. Neurological abnormality was related both to the severity of the deformity and the surgical outcome. It was seen in 38% of feet with grade-2 and in 53% of feet with grade-3 deformity. A fair surgical result was obtained in 36% of feet with a conduction deficit and in only 6% with no abnormality. These results suggest an association between neurological abnormality as demonstrated by SSEPs or motor electrophysiological studies and the severity of deformity in club foot and its response to surgical treatment.

Seven children who had partial arrest of the growth plate after neonatal arterial cannulation, developed obvious skeletal changes in adolescence. Cannulation of the femoral artery produced ischaemia which led to four cases of ipsilateral shortening of the lower limb and one of partial arrest of the proximal femoral physis with subsequent coxa valga. The two arrests in the upper limb affected the humerus, ulna and radius, and the radius alone, after cannulation of the brachial and radial arteries, respectively. These late effects of cannulation are not widely appreciated, and may occur as a result of thrombosis rather than extravasation.

We compared the prognostic value of the Catterall grouping, the Salter-Thompson grading, the arthrographic shape of the femoral head, and the Herring lateral pillar grouping during the fragmentation stage of Perthes’ disease in 73 patients with 81 affected hips. Radiographs were available for study from the onset of the disease until skeletal maturity. We used the Stulberg classification to assess outcome.

The Herring grade and arthrographic sphericity proved to be the best predictors of final outcome. Combining these two values further increased the predictive value. All but one patient in Herring group A achieved an excellent outcome. In Herring group B, the age of the child and the sphericity of the femoral head influenced the end result. If the child was less than seven years old at the onset of symptoms the prognosis was invariably good and all spherical hips in group B had a good outcome with Stulberg grades 1 or 2. Moderately and severely deformed hips on arthrography resulted in Stulberg 3 and 4 hips. None of the hips in Herring group C had a normal appearance at maturity and the outcome was not significantly influenced by the age at onset or the arthrographic appearance.

A technique for epiphysiodesis using a cannulated tubesaw has been developed to combine the precision of the original Phemister method with newer percutaneous methods. The approach is unilateral, and requires minimal access. Reinsertion of the removed core of bone reduces haemorrhage from the defect and augments arrest of the growth plate.

In 35 patients treated by this method predicted discrepancies of 2 to 4.5 cm were reliably reduced to 0.7 ± 0.6 cm, with no serious complications. The timing of surgery is critical, and relies upon careful monitoring of the pattern of discrepancy over several years, using clinical and radiographic measurements. Undercorrection of the disparity in three patients was the direct result of late referral.