Wolff's Law proposes that trabecular bone adapts in response to mechanical loading and that trabeculae align with the trajectory of predominant loads. The current study is aimed to investigate trabecular orientation in the tibia in patients with osteoarthritis of the knee. Consistent with Wolff's Law, it was hypothesised that orientation would reflect the mechanical loading of the joint and hence that there would be a correlation between the trabecular orientation and the mechanical axis of the lower limb. 51 anonymised radiographs from patients with osteoarthritis were analysed using ImageJ (National Institute of Health). Each patient had both a standard anteroposterior radiograph of the knee and a long leg view taken while weight bearing. For each anteroposterior radiograph, the angle of the femoral shaft and tibial shaft were measured. The femoral shaft – tibial shaft (FS -TS) angle was then calculated as the difference between the two, as described by Sheehy et al. (2011). A medial rectangle was selected with the top, bottom, medial and lateral borders being the sclerotic bone, the growth line, the bone edge and the centre of the medial tibial spine. Corresponding measurements were done on the lateral side. Trabecular orientation of both areas was measured using OrientationJ (an ImageJ plugin). In all cases the medial and lateral orientation angles were expressed relative to the angle of the tibial shaft. The mechanical axis of the lower limb was measured from the full length radiographs by calculating the angle formed by the femoral and tibial axes, as described by Goker and Block. All measurements were done independently by two observers, SAS and SL.Introduction
Methods
The outcome of 56 children (61 shoulders) treated
surgically at the Rizzoli Institute between April 1975 and June 2010
for congenital elevation of the scapula is reported. There were
31 girls and 25 boys with a mean age at surgery of 6.4 years (2
to 15). The deformity involved the right shoulder in 20 cases, the
left in 31 and was bilateral in five. The degree of the deformity
was graded clinically and radiologically according to the classifications
of Cavendish and Rigault, respectively. All patients underwent a
modified Green procedure combined, in selected cases, with resection
of the superomedial portion of the scapula and excision of any omovertebral
connection. After a mean follow-up of 10.9 years (1 to 29.3), there
was cosmetic improvement by at least one Cavendish grade in 54 shoulders (88.5%).
The mean abduction of the shoulder improved from 92° (50° to 155°)
to 112° (90° to 170°) and the mean flexion improved from 121° (80°
to 160°) to 155° (120° to 175°). The unsatisfactory cosmetic result
in seven shoulders was due to coexistent scoliosis in two cases
and insufficient reduction of the scapular elevation in the other
five. An incomplete upper brachial plexus palsy occurred post-operatively
in three patients but resolved within seven months. We suggest that a modified Green procedure combined with resection
of the superomedial portion of the scapula provides good cosmetic
and functional results in patients with Sprengel’s shoulder.
