ABSTRACTS 683

age 15, in keeping with findings in previous studies that triplane and Tillaux fractures occur in closing growth plates.

CT scanning was found to be of use in each case in diagnosing the full extent of the fracture and determining the appropriate treatment. It also allowed better overall understanding of the detailed anatomy of these often complex fractures so that a logical classification can be made.

THE IRRITABLE HIP IN CHILDREN: COULD WE BE DOING FEWER RADIOGRAPHS? A. J. BOOTH, D. R. BICKERSTAFF, L. NEAL and M. J. BELL Sheffield Children's Hospital, Sheffield

Transient synovitis of the hip is a common disorder in children and is often accompanied by a joint effusion.

A prospective study has been undertaken of 100 consecutive patients presenting at the Sheffield Children's Hospital with acute hip pain. The aim was to follow the natural history of the joint effusion ultrasonically, and hence determine whether radiographs are neccessary.

The patients were initially assessed by ultrasound, radiographic and clinical examinations. They were then followed up by clinicians for at least 3 months. Further ultrasound scans were performed at predeter- mined intervals and radiographic examinations were only performed as clinically indicated.

The natural history of transient synovitis is that the effusion resolves with conservative treatment within 2 weeks in 85% of our patients, In one patient in whom the effusion persisted for 5 weeks, further radio- graphy confirmed a diagnosis of Perthes disease.

Data will be presented to show that in the majority of cases ultra- sound examinations only are required. The presence of a persistent effusion should alert the clinicians and radiologists to the presence of other pathology.

ATLANTO-AXIAL SUBLUXATION IN ANKYLOSING SPONDYLITIS A. R. M. WILSON, A. J. CHUCK and J. K. LLOYD-JONES Harlow Wood Orthopaedic Hospital, Nottinghamshire

Atlanto-axial subluxation is a well recognised and potentially fatal complication of many of the inflammatory arthropathies. It occurs most commonly in rheumatoid disease and is said to be a rare occur- rence in ankylosing spondylitis. We have studied the prevalence of this complication in a population of 208 patients (175 male, 33 female: age range 13 to 78 years) with ankylosing spondylitis. After exclusions, seven (four female; three male) were found to have radiological evi- dence of significant atlanto-axial subluxation (atlanto-dental interval >2.5 mm on a flexion lateral radiograph) representing a prevalence of 3.4%. All had a duration of disease of at least 10 years and females appeared to be at particular risk. Four had significant neurological deficit attributable to cervical cord compression but only two required surgery to maintain stability. The remainder fused spontaneously on conservative therapy. Atlanto-axial subluxation is a rare but poten- tially serious complication of ankylosing spondylitis. It may occur in the absence of any associated symptoms or signs and is a potential risk factor in any patient with chronic active disease undergoing general anaesthesia.

THE FACET JOINTS IN CHRONIC LOW BACK PAIN I. W. McCALL, E. COLHOUN, V. N. CASSAR-PULLICINO The Robert Jones" & Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire

Intra-articular injections of local anaesthetic (LA) into the facet joints has been practised as a diagnostic and therapeutic procedure for a number of years. A study on patients with acute low back pain (LBP) has suggested a 50% response rate but results in the more chronic patient have been less encouraging and the relationship between dis- cogenic and facet pain in the chronic LBP sufferer has not been addressed.

The aim of the study was to assess the importance of these two sites as pain sources in this group of patients. 245 patients presenting with chronic LBP with or without non-dermatomal leg pain and in whom no

previous surgery has been performed, have undergone facet arthro- graphy and lumbar discography at the lower three lumbar levels. 0.5% Bivocaine was injected into the joints on the basis of one level per day. The response of the patient's symptoms to the LA was monitored over the following 4 hours. Lumbar discography was performed by the postero-lateral approach and both disc morphology and symptom reproduction was recorded. 205 patients had at least one mor- phologically abnormal disc. 123 (60%) were associated with symptom reproduction and 59 had no induced pain (29%). The remaining 23 patients (11%) had total disc resorption at one level precluding exam- ination at that level but adjacent discs were unassociated with symp- tom provocation. Forty patients had normal discs at the lower three lumbar levels.

Of the 245 patients, 45 (18.4%) had complete relief of symptoms after LA into the facets. There was no difference between those patients with symptomatic discs (19%), non-symptomatic discs (25%) or with total disc resorption (17%). Of the 40 patients with normal three level lumbar discography only two (5%) had complete relief of symptoms following facet injections.

This study indicates that the disc is more commonly a significant pain source than the intracapsular portion of the facet joint in patients with chronic LBP. The facets do not appear to be a common alternative pain source when the discs are normal.

STEEL COIL EMBOLISATION OF TRACK AFTER PERCUTANEOUS LIVER BIOPSY IN HIGH-RISK PATIENTS A. ADAM and D. J. ALLISON Hammersmith Hospital, London

The traditional method of liver biopsy in patients with abnormal coagulation utilises the transjugular approach but this is cumbersome, time-consuming, prone to complications and often produces a biopsy specimen which is too small. Our technique uses a purpose-made system, consisting of a Tru-cut-type of needle inserted into the liver within a plastic sheath. Following the biopsy, contrast medium is injected through the sheath to demonstrate the source of any bleeding; this is usually a communication between the biopsy track and a portal venous radicle. A steel coil preloaded onto a special delivery wire is then advanced through the sheath under fluoroscopic screening and deposited in such a position as to occlude any communication between the track and blood vessels. This instrument allows very accurate positioning of the coils which results in rapid haemostatis. If bleeding does not stop immediately further steel coils can be inserted as neces- sary. Before removal of the sheath contrast medium is injected to show whether the communication(s) between the track and hepatic blood vessels have been satisfactorily occluded. During removal of the sheath further coils may be deposited along its track as necessary. This technique has been used successfully in eight patients.

COMPUTED TOMOGRAPHy OF HEPATIC METASTASES IN OVARIAN CARCINOMA S. J. GOLDING and T. PETSAS University of Oxford and Churchill Hospital, Oxfor d

This study was carried out to establish the character on computed tomography (CT) of hepatic metastases due to ovarian carcinoma. One hundred and thirty-eight patients underwent CT during disease staging or restaging. Focal liver lesions were found in 26, the liver being the only site of disease spread in seven. Hepatic metastases varied widely in number, size and character. Both well defined and poorly defined lesions were seen but the character of metastases appeared constant in individual patients. Attenuation values ranged from 55 HU to -13 HU. No histological correlation was observed.

There appears to be a subgroup of patients in whom metastases appear as well defined lentiform low attenuation lesions beneath the liver capsule. These were observed in eight patients and were not associated with lesions elsewhere in the liver. Percutaneous aspiration in selected patients revealed cysts containing changed blood and viable malignant cells. These lesions are unlikely to be due to necrosis of existing metastases. Although cystic, their occurrence is not limited to patients with primary cystadenocarcinoma.

Lentiform subcapsular cysts should be recognised as a characteristic appearance in some patients of liver metastases from ovarian carcinoma.