Lateral epicondylitis and beyond: imaging of lateral elbow pain with clinical-radiologic correlation.

The diagnosis of lateral epicondylitis is often straightforward and can be made on the basis of clinical findings. However, radiological assessment is valuable where the clinical picture is less clear or where symptoms are refractory to treatment. Demographics, aspects of clinical history, or certain physical signs may suggest an alternate diagnosis. Knowledge of the typical clinical presentation and imaging findings of lateral epicondylitis, in addition to other potential causes of lateral elbow pain, is necessary. These include entrapment of the posterior interosseous and lateral antebrachial cutaneous nerves, posterolateral rotatory instability, posterolateral plica syndrome, Panner's disease, osteochondritis dissecans of the capitellum, radiocapitellar overload syndrome, occult fractures and chondral-osseous impaction injuries, and radiocapitellar arthritis. Knowledge of these potential masquerades of lateral epicondylitis and their characteristic clinical and imaging features is essential for accurate diagnosis. The goal of this review is to provide an approach to the imaging of lateral elbow pain, discussing the relevant anatomy, various causes, and discriminating factors, which will allow for an accurate diagnosis.

Chronology of the radiographic appearances of the calcium sulphate-calcium phosphate synthetic bone graft composite following resection of bone tumours--a preliminary study of the normal post-operative appearances.

OBJECTIVE: To describe the normal chronological radiographic appearances of the calcium sulphate-calcium phosphate (CaSO(4)/CaPO(4)) synthetic graft material following bone tumour resection during the processes of graft resorption and new bone incorporation into the post-resection defect. MATERIALS AND METHODS: Retrospective review of our oncology database identified patients who had undergone serial radiographic assessment after treatment with the CaSO(4)/CaPO(4) synthetic graft following bone tumour resection. Post-operative radiographs were assessed for (1) partial resorption of graft material with partial ingrowth of new bone at the graft site and (2) complete resorption of graft material with complete incorporation of new bone into the graft site. The pattern of resorption of graft material was also documented. Any radiographic evidence of complication was recorded. Radiographs were also divided into groups according to their interval from surgery to establish a pattern of time-related changes. RESULTS: A total of 11 patients were identified from our database. Partial resorption of graft material/partial ingrowth of new bone was seen in nine patients, initially observed at a mean of 1.4 months from surgery. Resorption commenced peripherally with gradual inward progression in 100% (9 of 9) of cases. Complete resorption of graft/complete new bone incorporation at the graft site was seen in 89% (8 of 9) of cases followed up for more than 5 months after surgery. The other patient developed recurrence of tumour at 14 months, before complete incorporation was demonstrated. The mean time to complete incorporation of new bone was 5 months. Two patients have, to date, been followed up at 2 and 3 months respectively with a pattern of peripheral graft resorption observed so far in both cases. Ten of 13 (77%) radiographs performed 1-3 months after surgery demonstrated peripheral resorption of graft material with partial osseous ingrowth into the defect. Seven of eight (88%) radiographs performed 6-12 months after surgery demonstrated complete new bone incorporation at the graft site with graft material completely resorbed. Ten of 11 (91%) radiographs performed 1 year after surgery demonstrated complete new bone incorporation, the other examination demonstrating recurrence. CONCLUSION: Our preliminary observations suggest a characteristic, time-related radiographic pattern during the processes of CaSO(4)/CaPO(4) bone graft resorption and complete new bone incorporation. This pattern can be directly related to processes that occur at the molecular level. Radiographic findings that are not in keeping with this may merit closer follow-up.

Magnetic resonance imaging appearances following hindquarter amputation for pelvic musculoskeletal malignancy.

OBJECTIVE: To describe our experience of the magnetic resonance imaging (MRI) appearances after hindquarter amputation, focusing on the normal pattern of time-related changes in signal intensity within the amputation flap and appearances of local disease recurrence. MATERIALS AND METHODS: This was a retrospective review of the records of patients identified on our orthopaedic oncology database who had undergone hindquarter amputation at our centre. Examinations were divided into one group consisting of 'normal' postoperative findings and another group demonstrating local recurrence. 'Normal' postoperative findings were assessed for signal intensity, morphology and presence of the 'muscle texture sign' within the amputation flap. Examinations were grouped according to time from surgery. Examinations demonstrating local recurrence were assessed for site, signal intensity, morphology and axial dimensions of recurrent tumour. Comparison was made to pre-operative imaging. RESULTS: Thirty-five patients with postoperative MR images were identified. Seventy-seven examinations were reviewed (range 1-18 per patient). The 'normal group' comprised 18 patients (seven female, 11 male, mean age 44 years, range 16-75 years), with 47 examinations reviewed. The 'muscle texture sign' was preserved in all examinations in this group. Up to 6 months after surgery, 100% (10) of examinations showed hyperintense T2- and short-tau inversion recovery (STIR-weighted) signals within the muscle flap, indicating oedema. Only after 4 years was the muscle flap signal isointense in all cases (13). Up to 6 months after surgery, 50% (5 of 10) of examinations demonstrated flap swelling, but after 1 year, 100% (28) showed atrophy. Twenty percent (2 of 10) of examinations 0-6 months from surgery showed hyperintense T1-weighted signal within the muscle flap, consistent with fatty infiltration, but after 2 years, 100% (20) showed a hyperintense T1-weighted signal. The 'local recurrence' group comprised 20 patients (six female, 14 male, mean age 45.7 years, range 14-69 years), with 30 examinations demonstrating recurrent disease or metastasis. There were 23 recurrent tumours, of which 43% (10) were in the muscle component of the amputation flap, 13% (3 of 23) were in subcutaneous tissues of the flap, 13% (3 of 23) were at the posterior margin of the bone resection and 13% (3 of 23) were paraspinal. All recurrent tumours demonstrated hyperintense T2 and STIR signals. The signal intensity pattern of recurrence closely followed that of the original tumour. The 'muscle texture sign' was absent in all examinations demonstrating recurrence in muscle flap. CONCLUSION: A pattern of time-related signal intensity and morphological changes is observed within normal hindquarter amputation flaps on MRI. Recurrent disease is most likely to occur within the muscle flap, typically of high T2-weighted signal intensity and characteristically follows the signal pattern of the original tumour.