Aims

The aim of this study was to evaluate the correlation between Salter’s criteria and Kalamchi’s classification of avascular necrosis in patients treated for developmental dysphasia of the hip (DDH).

We reviewed the medical records of 115 patients with 130 hips with developmental dysplasia with complete dislocation in the absence of a neuromuscular disorder, spontaneous reduction with a Pavlik harness, and a minimum of 14 years’ follow-up. The mean age at the time of harness application was 4.8 months (1 to 12) and the mean time spent in the harness was 6.1 months (3 to 12). A total of 108 hips (83.1%) were treated with the harness alone and supplementary surgery for residual acetabular dysplasia, as defined by an acetabular index > 30°, was performed in 22 hips (16.9%).

An overall satisfactory outcome (Severin grade I or II) was achieved in 119 hips (91.5%) at a mean follow-up of 16 years (14 to 32) with a follow-up rate of 75%. Avascular necrosis of the femoral head was noted in 16 hips (12.3%), seven of which (44%) underwent supplementary surgery and nine (56%) of which were classified as satisfactory. The acetabular index was the most reliable predictor of residual acetabular dysplasia.

We performed a paired study of mature patients with Perthes’ disease to compare the radiological results after treatment between conservatively- and surgically-treated groups. One patient was selected from each group to create the pairs for this study. Each pair was strictly matched for gender, body mass index, age at onset, stage at the first visit, necrotic area and radiological at-risk signs and each was assessed by comparing the values of six radiological measurements.

Eighteen pairs (36 hips) fitted the criteria. The radiological measurements which showed a statistically better result in the surgical groups were Mose’s method, the acetabular-head index and leg-length discrepancy. There were no statistical differences in the slope of the acetabular roof and the articulotrochanteric distance. Four hips in the conservative group were in Stulberg class II, five in class III and nine in class IV. In the surgical group, 13 were in Stulberg class II, four in class III and one in class IV.

We conclude that surgical treatment improved the sphericity of the femoral head and provided greater acetabular cover, but did not reform the acetabular roof.

It was noteworthy that a greater leg-length discrepancy and a smaller articulotrochanteric distance were not seen in the surgical group. Our study suggests that surgical treatment is preferable in patients with severe Perthes’ disease.

We have observed the natural history without treatment of 46 limbs in 29 patients with infantile tibia vara and a metaphyseal-diaphyseal angle (MDA) of more than 11°. The femorotibial angle (FTA) and MDA were measured, and Langenskiöld’s classification of radiological changes in the proximal medial metaphysis of the tibia was used. In 22 limbs which were not in Langenskiöld stages II to III the condition resolved spontaneously without treatment. Of the remaining 24 which were in stages II to III, in 18 it resolved spontaneously by the age of six years, but six showed little or no improvement at the latest follow-up. It was impossible to differentiate by measuring the FTA or MDA whether spontaneous resolution could be expected before the age of four years. There was no difference in the rate of resolution of the deformity between those patients who had been treated by a brace and those who had received no treatment. We advise no initial treatment but review at six-monthly intervals until the age of four years, even in patients with Langenskiöld stage-II to stage-III deformity. When a deformity persisted or progressed we carried out a corrective osteotomy after the age of four years.

We studied in vivo the talonavicular alignment of club foot in infants using MRI. We examined 26 patients (36 feet) with congenital club foot. The mean age at examination was 9.0 months (4 to 12). All analyses used MRI of the earliest cartilaginous development of the tarsal bones in the transverse plane, rather than the ossific nucleus. The difference in the mean talar neck angle (44.0 ± 8.1°) in club foot was statistically significant (p < 0.001) when compared with that of the normal foot (30.8 ± 5.5°). The difference between the mean angles in the group treated by operation (47.9 ± 6.7°) and those treated conservatively (40.1 ± 7.5°) was also statistically significant. The anatomical relationship between the head of the talus and the navicular was divided into two patterns, based on the position of the mid-point of the navicular related to the long axis of the head. In the operative group, 18 feet were classified as having a medial shift of the navicular and none had a lateral shift. In the conservative group, 12 showed a medial shift of the navicular and six a lateral shift. All nine unaffected normal feet in which satisfactory MRI measurements were made showed a lateral shift of the navicular.

Club feet had a larger talar neck angle and a more medially deviated navicular when compared with normal feet. This was more marked in the surgical group than in the conservative group.

We reviewed 33 patients (35 hips) after open reduction of congenital dislocation of the hip using Ludloff’s medial approach. The mean age at the time of operation was 14 months (5 to 29) and at the time of final follow-up 20.1 years (15 to 24) giving a mean duration of follow-up of 19.4 years (14 to 23). We evaluated the radiological results by the Severin classification and the extent of avascular necrosis using the criteria of Kalamchi.

At the latest review 16 hips (45.7%) were in Severin groups I or II (acceptable results) and 19 (54.3%) in Severin groups III, IV or V (unacceptable results). There was evidence of avascular necrosis in 15 hips (42.9%). The radiological results began to become worse at about the age of ten years when type-II avascular changes presented.

We conclude that Ludloff’s medial approach for open reduction is unsatisfactory for the treatment of congenital dislocation since about half of our patients required additional operations.

We used hydroxyapatite blocks to keep open Salter innominate osteotomies in 19 children (21 hips), avoiding the need for an autograft taken from the anterior superior iliac spine. Our results were satisfactory, with less deformation of the iliac bone, and a reduction of both blood loss and operating time.

The exact measurement of femoral head cover is essential for an assessment of reduction of congenital dislocation of the hip. We have compared standard anteroposterior radiographs with computerised tomograms and thereby classified the shape of the acetabular roof into four types. We found that the CE angle of Wiberg is a more reliable measure of head cover when the lateral point of bony condensation of the roof is chosen as the reference point rather than the edge of the bone, where these two points do not overlap. We conclude that head cover can be more accurately determined in younger children with dysplastic hips by our 'refined' CE angle, than by the original method of Wiberg.

Hip arthrography was performed in 19 patients in the initial stage of Perthes' disease. Sphericity and subluxation were measured and it was found that subluxation was independent of the femoral head deformity. We therefore tried to identify the cause of early subluxation: in seven patients a swollen ligamentum teres was thought to be responsible, and was associated with medial pooling of the contrast medium. A swollen ligamentum teres was seen in another seven cases; the other five arthrograms were normal. These findings were further clarified by enhanced CT scans, which confirmed that ligament swelling may be an important cause of early subluxation.