Level III.

Normal patello-femoral tracking is not well defined, and conventional radiological techniques do not allow imaging in the physiological, weight-bearing stance. A vertical-access open configuration magnetic resonance scanner allows imaging of patello-femoral tracking during weight-bearing and through a wide range of knee flexion. We imaged 40 asymptomatic knees in this way, producing axial scans which were analysed qualitatively and quantitatively using sulcus angle, congruence angle, lateral patello-femoral angle and patellar centralisation, to assess patellar tilt and displacement. Mild lateral tilting in hyperextension with the quadriceps relaxed was seen, but quantitative assessment of this was impeded by internal rotation of the femur in extension. One-half of the knees were slightly laterally displaced in hyper-extension, becoming central during the first 30 degrees of knee flexion. During passive flexion of the knee in a seated position, fewer knees were laterally tilted or displaced, and no consistent change was seen during flexion. These results indicate that mild lateral tilting and displacement can be normal phenomena in the weight-bearing knee in early flexion and should not necessarily be taken as evidence of abnormal tracking in symptomatic patients. Lateral to medial movement of the patella occurs during normal knee flexion. In addition, imaging in the weight-bearing knee can provide valuable information not gained by imaging during passive knee flexion.

We present the first study in vivo of meniscal movement in normal knees under load. Using an open MR scanner, allowing imaging in physiological positions in near to real-time, 16 young footballers were scanned moving from full extension to 90 degrees flexion in the sagittal and coronal planes. Excursion of the meniscal horns, radial displacement and meniscal height were measured. On weight-bearing, the anterior horn of the medial meniscus moves through a mean of 7.1 mm and the posterior horn through 3.9 mm, with 3.6 mm of mediolateral radial displacement. The height of the anterior horn increases by 2.6 mm and that of the posterior horn by 2.0 mm. The anterior horn of the lateral meniscus moves 9.5 mm and the posterior horn 5.6 mm, with 3.7 mm of radial displacement. The height of the anterior horn increases by 4.0 mm, and that of the posterior horn by 2.4 mm. In non-weight-bearing, the anterior horn of the medial meniscus moves 5.4 mm and the posterior horn 3.8 mm, with 3.3 mm of radial displacement. The anterior horn of the lateral meniscus moves 6.3 mm, and the posterior horn 4.0 mm, with 3.4 mm of radial displacement. The most significant differences between weight-bearing and non-weight-bearing were the movement and vertical height of the anterior horn of the lateral meniscus.

PurposeTo review the initial deformity and subsequent remodelling in posteromedial bowing of the tibia and the outcome of limb reconstruction in this condition.Patients and MethodsIn all, 38 patients with posteromedial bowing of the tibia presenting between 2000 and 2016 were identified. Mean follow-up from presentation was 78 months. A total of 17 patients underwent lengthening and deformity correction surgery, whilst three further patients are awaiting lengthening and deformity correction procedures.ResultsThe greatest correction of deformity occurred in the first year of life, but after the age of four years, remodelling was limited. The absolute leg-length discrepancy (LLD) increased throughout growth with a mean 14.3% discrepancy in tibial length. In the lengthening group, mean length gained per episode was 45 mm (35 to 60). Mean duration in frame was 192 days, with a mean healing index of 42.4 days/cm. Significantly higher rates of recurrence in LLD were seen in those undergoing lengthening under the age of ten years (p = 0.046). Four contralateral epiphysiodeses were also performed.ConclusionPosteromedial bowing of the tibia improves spontaneously during the first years of life, but in 20/38 (53%) patients, limb reconstruction was indicated for significant residual deformity and/or worsening LLD. For larger discrepancies and persistent deformity, limb reconstruction with a hexapod external fixator should be considered as part of the treatment options.Level of evidenceLevel IV (Case series)

Closed reduction, with concomitant adductor and psoas release when required and the use of a short leg plaster of Paris cast for three months, can produce good mid-term results in children with DDH aged less than two years. This protocol is not recommended for Tönnis 4 hips. Cite this article: Bone Joint J 2016;98-B:1548-53.

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Background: Bilateral developmental dysplasia of the hip (DDH) is believed to have a worse outcome than unilateral DDH with the optimal treatment unclear. To define indications for treatment we report a retrospective series of 92 hips (46 patients) who underwent closed reduction (CR) and/or open reduction (OR). Methods: A total of 58 hips in 29 patients underwent attempted CR using our standardized protocol. In the same 12 year time period, 54 hips in 27 patients underwent an OR. Outcome measures included resolution of acetabular dysplasia, need for further surgery, development of osteonecrosis (ON), and modified Severin Grade. Results: CR was successful in 57% of hips; in this group secondary surgery was required in 15% and ON was seen in 12%. In the OR group, 11% failed to stabilize and required further early surgery: ON rate was 15% overall, and secondary surgery was required in 5%. In Tonnis 2/3 hips younger than 2 years, Severin grading was comparable following CR and OR, with 92% and 90% graded as Severin 1, respectively. The rate of significant ON was higher after CR in Tonnis 2/3 hips (12%) than after OR (0%). Overall, Tonnis 4 hips did badly: 94% failed CR and following OR, further surgery for redislocation/residual dysplasia was required in 21%. Conclusions: CR can be successful in Tonnis 2/3 bilateral hips, with acceptable rates of secondary surgery, ON, and Severin grading, the latter equivalent to open reduction. Importantly, persisting with casting of a unilateral dislocation, to allow the contra-lateral hip to stabilize, does not have an adverse effect. CR is not advised in Tonnis 4 bilateral hips. Parents should be counseled that the outcome of surgery for bilateral hips is not as good as for unilateral DDH, particularly for Tonnis 4 hips which are more difficult to stabilize and more likely to require supplementary surgery even after open reduction. Level of evidence: Level IV—Therapeutic Study.

PurposeComplete fibula absence often presents with significant lower-limb deformity. Parental counselling regarding management is paramount in achieving the optimum functional outcome. Amputation offers a single surgical event with minimal complications. This study compares outcomes with an amputation protocol to those using an extension prosthesis.MethodThirty-two patients were identified. Nine patients (2 males, 7 females; median age at assessment of 23.5 years) used an extension prosthesis. Twenty-three patients (16  males, 7 females; median age at assessment of eight years) underwent 25 amputations during childhood. Mobility was assessed using SIGAM and K scores. Quality of life was assessed using the PedsQL inventory questionnaire; pain by a verbal severity score.ResultsThe 19 Syme and one Boyd amputation in 19 patients were performed early (mean age 15 months). Four Syme and one trans-tibial amputation in four patients took place in older children (mean age 6.6 years). Only two underwent tibial kyphus correction to aid prosthetic fitting. K scores were significantly higher (mean 4 vs 2) and pain scores lower in the amputation group allowing high impact activity compared with community ambulation with an extension prosthesis. The SIGAM and PedsQL scores were all better in the amputation group, but not significantly so.ConclusionChildhood amputation for severe limb length inequality and foot deformity in congenital fibula absence offers excellent short-term functional outcome with prosthetic support. The tibial kyphus does not need routine correction and facilitates prosthetic suspension. Accommodative extension prostheses offer reasonable long-term function but outcome scores are lower.