We describe injuries to the posterior root of the medial meniscus in patients with spontaneous osteonecrosis of the medial compartment of the knee. We identified 30 consecutive patients with spontaneous osteonecrosis of the medial femoral condyle. The radiographs and MR imaging were reviewed. We found tears of the posterior root of the medial meniscus in 24 patients (80%). Of these, 15 were complete and nine were partial. Complete tears were associated with > 3 mm of meniscal extrusion. Neither the presence of a root tear nor the volume of the osteonecrotic lesion were associated with age, body mass index (BMI), gender, side affected, or knee alignment. The grade of osteoarthritis was associated with BMI.

Although tears of the posterior root of the medial meniscus were frequently present in patients with spontaneous osteonecrosis of the knee, this does not prove cause and effect. Further study is warranted.

We carried out metal artefact-reduction MRI, three-dimensional CT measurement of the position of the component and inductively-coupled plasma mass spectrometry analysis of cobalt and chromium levels in whole blood on 26 patients with unexplained pain following metal-on-metal resurfacing arthroplasty.

MRI showed periprosthetic lesions around 16 hips, with 14 collections of fluid and two soft-tissue masses. The lesions were seen in both men and women and in symptomatic and asymptomatic hips. Using three-dimensional CT, the median inclination of the acetabular component was found to be 55° and its positioning was outside the Lewinnek safe zone in 13 of 16 cases. Using inductively-coupled plasma mass spectrometry, the levels of blood metal ions tended to be higher in painful compared with well-functioning metal-on-metal hips.

These three clinically useful investigations can help to determine the cause of failure of the implant, predict the need for future revision and aid the choice of revision prostheses.

Objectives

The purpose of this study was to clarify the appearance of the reparative tissue on the articular surface and to analyse the properties of the reparative tissue after hemicallotasis osteotomy (HCO) using MRI T1ρ and T2 mapping.

Aims

Acetabular dysplasia is frequently associated with intra-articular pathology such as labral tears, but whether labral tears should be treated at the time of periacetabular osteotomy (PAO) remains controversial. The purpose of this study was to compare the clinical outcomes and radiographic corrections of PAO for acetabular dysplasia between patients with and without labral tears pre-operatively.

Back pain is a common symptom in children and adolescents. Here we review the important causes, of which defects and stress reactions of the pars interarticularis are the most common identifiable problems. More serious pathology, including malignancy and infection, needs to be excluded when there is associated systemic illness. Clinical evaluation and management may be difficult and always requires a thorough history and physical examination. Diagnostic imaging is obtained when symptoms are persistent or severe. Imaging is used to reassure the patient, relatives and carers, and to guide management.

Cite this article: Bone Joint J 2014;96-B:717–23.

We report the case of an eight-month-old girl who presented with a poliomyelitis-like paralysis in her left upper limb caused by enterovirus 71 infection. She recovered useful function after nerve transfers performed six months after the onset of paralysis. Early neurotisation can be used successfully in the treatment of poliomyelitis-like paralysis in children.

We carried out an MRI study of the lumbar spine in 15 patients with achondroplasia to evaluate the degree of stenosis of the canal. They were divided into asymptomatic and symptomatic groups. We measured the sagittal canal diameter, the sagittal cord diameter, the interpedicular distance at the mid-pedicle level and the cross-sectional area of the canal and spinal cord at mid-body and mid-disc levels.

The MRI findings showed that in achondroplasia there was a significant difference between the groups in the cross-sectional area of the body canal at the upper lumbar levels. Patients with a narrower canal are more likely to develop symptoms of spinal stenosis than others.

The June 2013 Spine Roundup³⁶⁰ looks at: the benefit of MRI in the follow-up of lumbar disc prolapse; gunshot injury to the spinal cord; the link between depression and back pain; floating dural sack sign; short segment fixation at ten years; whether early return to play is safer than previously thought; infection in diabetic spinal patients; and dynesis.

We describe a case of oncogenic osteomalacia in an adult male who presented with low back pain and bilateral hip pain. Extensive investigations had failed to find a cause. A plain pelvic radiograph showed Looser’s zones in both femoral necks. MRI confirmed the presence of insufficiency fractures bilaterally in the femoral head and neck. Biochemical investigations confirmed osteomalacia which was unresponsive to treatment with vitamin D and calcium. A persistently low serum phosphate level suggested a diagnosis of hypophosphataemic osteomalacia. The level of fibroblast growth factor-23 was highly raised, indicating the cause as oncogenic osteomalacia. This was confirmed on positron-emission tomography, MRI and excision of a benign fibrous histiocytoma following a rapid recovery.

The diagnosis of oncogenic osteomalacia may be delayed due to the non-specific presenting symptoms. Subchondral insufficiency fractures of the femoral head may be missed unless specifically looked for.

Giant-cell tumour of the synovium is known to affect the fingers or toes of adults. It has seldom been described in the spine and rarely in the thoracic vertebrae or in a child. The lesions of giant-cell tumour of the synovium have a classical radiological appearance, but require a high index of suspicion for correct recognition. Unlike giant-cell tumour of the synovium at other well-known sites, spinal lesions lack the characteristic papillary architecture, thereby raising other diagnostic possibilities. We describe a giant-cell tumour of the synovium of the left facet joint of a thoracic vertebra in a nine-year-old girl. The tumour was treated successfully by surgical excision.

We examined the reliability of radiological findings in predicting segmental instability in 112 patients (56 men, 56 women) with a mean age of 66.5 years (27 to 84) who had degenerative disease of the lumbar spine. They underwent intra-operative biomechanical evaluation using a new measurement system. Biomechanical instability was defined as a segment with a neutral zone > 2 mm/N. Risk factor analysis to predict instability was performed on radiographs (range of segmental movement, disc height), MRI (Thompson grade, Modic type), and on the axial CT appearance of the facet (type, opening, vacuum and the presence of osteophytes, subchondral erosion, cysts and sclerosis) using multivariate logistic regression analysis with a forward stepwise procedure. The facet type was classified as sagittally orientated, coronally orientated, anisotropic or wrapped.

Stepwise multivariate regression analysis revealed that facet opening was the strongest predictor for instability (odds ratio 5.022, p = 0.009) followed by spondylolisthesis, MRI grade and subchondral sclerosis. Forward stepwise multivariate logistic regression indicated that spondylolisthesis, MRI grade, facet opening and subchondral sclerosis of the facet were risk factors. Symptoms evaluated by the Short-Form 36 and visual analogue scale showed that patients with an unstable segment were in significantly more pain than those without. Furthermore, the surgical procedures determined using the intra-operative measurement system were effective, suggesting that segmental instability influences the symptoms of lumbar degenerative disease.

This study evaluates factors related to myelopathic symptoms in patients with ossification of the posterior longitudinal ligament (OPLL). A total of 87 patients with OPLL were included. Of these, 53 (Group I) had no symptoms or presented with neck pain and radiculopathy and 34 (Group II) had myelopathic symptoms. Gender, age, and history of trauma were evaluated in the two groups. The range of movement of the cervical spine was measured using plain radiographs. The number of involved segments, type of OPLL, and maximal compression ratio were analysed using CT and signal change in the spinal cord was evaluated using MRI.

The patients’ age was found to be significant (p = 0.001). No difference was found between gender and the range of movement in the two groups. The maximum compression of the spinal canal showed a difference (p = 0.03). The signal change of the spinal cord was different between the two groups. In patients with OPLL of the cervical spine, myelopathic symptoms are not related to the range of movement or the number of involved segments.

Patients from a randomised trial on resurfacing hip arthroplasty (RHA) (n = 36, 19 males; median age 57 years, 24 to 65) comparing a conventional 28 mm metal-on-metal total hip arthroplasty (MoM THA) (n = 28, 17 males; median age 59 years, 37 to 65) and a matched control group of asymptomatic patients with a 32 mm ceramic-on-polyethylene (CoP) THA (n = 33, 18 males; median age 63 years, 38 to 71) were cross-sectionally screened with metal artefact reducing sequence-MRI (MARS-MRI) for pseudotumour formation at a median of 55 months (23 to 72) post-operatively. MRIs were scored by consensus according to three different classification systems for pseudotumour formation.

Clinical scores were available for all patients and metal ion levels for MoM bearing patients.

Periprosthetic lesions with a median volume of 16 mL (1.5 to 35.9) were diagnosed in six patients in the RHA group (17%), one in the MoM THA group (4%) and six in the CoP group (18%). The classification systems revealed no clear differences between the groups. Solid lesions (n = 3) were exclusively encountered in the RHA group. Two patients in the RHA group and one in the MoM THA group underwent a revision for pseudotumour formation. There was no statistically significant relationship between clinical scoring, metal ion levels and periprosthetic lesions in any of the groups.

Periprosthetic fluid collections are seen on MARS-MRI after conventional CoP THA and RHA and may reflect a soft-tissue collection or effusion.

Currently available MRI classification systems seem to score these collections as pseudotumours, causing an-overestimatation of the incidence of pseudotumours.

Cite this article: Bone Joint J 2015;97-B:1175–82.

Metal-on-metal total hip replacement has been targeted at younger patients with anticipated long-term survival, but the effect of the production of metal ions is a concern because of their possible toxicity to cells. We have reviewed the results of the use of the Ultima hybrid metal-on-metal total hip replacement, with a cemented polished tapered femoral component with a 28 mm diameter and a cobalt-chrome (CoCr) modular head, articulating with a 28 mm CoCr acetabular bearing surface secured in a titanium alloy uncemented shell.

Between 1997 and 2004, 545 patients with 652 affected hips underwent replacement using this system. Up to 31 January 2008, 90 (13.8%) hips in 82 patients had been revised. Pain was the sole reason for revision in 44 hips (48.9%) of which 35 had normal plain radiographs. Peri-prosthetic fractures occurred in 17 hips (18.9%) with early dislocation in three (3.3%) and late dislocation in 16 (17.8%). Infection was found in nine hips (10.0%).

At operation, a range of changes was noted including cavities containing cloudy fluid under pressure, necrotic soft tissues with avulsed tendons and denuded osteonecrotic upper femora. Corrosion was frequently observed on the retrieved cemented part of the femoral component. Typically, the peri-operative findings confirmed those found on pre-operative metal artefact reduction sequence MRI and histological examination showed severe necrosis.

Metal artefact reduction sequence MRI proved to be useful when investigating these patients with pain in the absence of adverse plain radiological features.

Objectives

The purpose of this study was to investigate whether the femoral head–neck contour, characterised by the alpha angle, varies with the stage of physeal maturation using MRI evaluation of an asymptomatic paediatric population.

The October 2014 Spine Roundup³⁶⁰ looks at: microdiscectomy is not exactly a hands-down winner; lumbar spinal stenosis unpicked; Wallis implant helpful in lumbosacral decompression; multidisciplinary rehabilitation is good for back pain; and understanding the sciatic stretch test.

We present a case of post-traumatic osteonecrosis of the radial head in a 13-year-old boy which was treated with costo-osteochondral grafts. A satisfactory outcome was seen at a follow-up of two years and ten months.

Although costo-osteochondral grafting has been used in the treatment of defects in articular cartilage, especially in the hand and the elbow, the extension of the technique to manage post-traumatic osteonecrosis of the radial head in a child has not previously been reported in the English language literature. Complete relief of pain was obtained and an improvement in the range of movement was observed. The long-term results remain uncertain.

Transient osteoporosis of the hip is a disorder characterised by pain, and associated with temporary osteopaenia. Although osteopaenia is the essence of the condition, data do not exist about the local bone density of the femoral neck if no medication is administered. We describe three patients who were treated with limitation of weight-bearing only. Repeated bone mineral density measurements were obtained, and that at the femoral neck was lowest two months after the onset of the condition. The mean reduction in bone mineral density when compared with an age-matched control group was 13% (3% to 24%). Spontaneous recovery was observed in all patients.

Cancellous allograft bone chips are commonly used in the reconstruction of defects in bone after removal of benign tumours. We investigated the MRI features of grafted bone chips and their change over time, and compared them with those with recurrent tumour. We retrospectively reviewed 66 post-operative MRIs from 34 patients who had undergone curettage and grafting with cancellous bone chips to fill the defect after excision of a tumour. All grafts showed consistent features at least six months after grafting: homogeneous intermediate or low signal intensities with or without scattered hyperintense foci (speckled hyperintensities) on T1 images; high signal intensities with scattered hypointense foci (speckled hypointensities) on T2 images, and peripheral rim enhancement with or without central heterogeneous enhancements on enhanced images. Incorporation of the graft occurred from the periphery to the centre, and was completed within three years. Recurrent lesions consistently showed the same signal intensities as those of pre-operative MRIs of the primary lesions. There were four misdiagnoses, three of which were chondroid tumours.

We identified typical MRI features and clarified the incorporation process of grafted cancellous allograft bone chips. The most important characteristics of recurrent tumours were that they showed the same signal intensities as the primary tumours. It might sometimes be difficult to differentiate grafted cancellous allograft bone chips from a recurrent chondroid tumour.

Cite this article: Bone Joint J 2015;97-B:121–8.

Bertolotti’s syndrome is characterised by anomalous enlargement of the transverse process(es) of the most caudal lumbar vertebra which may articulate or fuse with the sacrum or ilium and cause isolated L4/5 disc disease.

We analysed the elective MR scans of the lumbosacral spine of 769 consecutive patients with low back pain taken between July 2003 and November 2004. Of these 568 showed disc degeneration. Bertolotti’s syndrome was present in 35 patients with a mean age of 32.7 years (15 to 60). This was a younger age than that of patients with multiple disc degeneration, single-level disease and isolated disc degeneration at the L4/5 level (p ≤ 0.05). The overall incidence of Bertolotti’s syndrome in our study was 4.6% (35 of 769). It was present in 11.4% (20 patients) of the under-30 age group.

Our findings suggest that Bertolotti’s syndrome must form part of a list of differential diagnoses in the investigation of low back pain in young people.