Non-biologic device for ACJ instability yields better shoulder scores than Weaver-Dunn procedure
LIVERPOOL, United Kingdom — At the start of his career, W. Angus Wallace, MB ChB, FRCS(Ed & Eng), FRCSEd(Orth), FFSEM(UK), FHKCOS(Hon) FMOT(Hon), used a Weaver-Dunn procedure for chronic and acute acromioclavicular joint stabilization. But, during his Sir Walter Mercer Lecture at the British Orthopaedic Association, here, he said a technique he now uses that involves a device he co-invented produces a stronger construct postoperatively and patients only need to wear a sling 2 weeks after treatment.
Updates to the LockDown Shoulder Stabilisation System device (LockDown Medical Ltd.), which is made of double-braided polyester, now help mitigate coracoid erosion, a problem sometimes seen with an earlier generation of the device, according to Wallace. The artificial ligament he discussed is anchored into the clavicle in four places to anteriorly reduce the acromioclavicular joint with the help of hard loop.
Angus W. Wallace
“Why does it work? We have put in a lot of LockDowns. We are now putting in 70 a year in Nottingham. Maybe more than that. Worldwide 12,000 have now been inserted. By studying the histology of the ingrowth of soft tissue into the LockDown, we have been able to learn what happens to LockDown after insertion,” Wallace said.
A pseudo ligament develops after insertion, which is sometimes thick, and that has led to the long survival after the procedure, according to Wallace.
“Beware when putting the device in of infection,” he said, noting some cases of Propionibacterium acnes infection have resulted in local bone osteonecrosis. Other than that, he said it lasts.
The device’s weak link, according to Wallace, is its hard loop “because it has no soft tissue in-growth.”
In a retrospective review of 55 non-randomized patients with chronic ACJ dislocations, the Oxford shoulder score, where the best score is 48, was 42 in patients after the Weaver-Dunn procedure and 45 in patients after the LockDown procedure. The more sensitive Nottingham Clavicle Score identified a significant difference with the two techniques. Of 100 possible points, the Weaver-Dunn group scored 81 and the LockDown group scored 93, Wallace said. – by Susan M. Rapp
Wallace WA. The Sir Walter Mercer Lecture: A lifetime experience of repairing joint ligaments with artificial augmentation at the shoulder, sternoclavicular joint, elbow and ankle. Presented at: British Orthopaedic Association Annual Congress; Sept. 15-18, 2015; Liverpool, United Kingdom.
Disclosure: Wallace reports he is a co-inventor of the LockDown, but no longer has any commitments to any companies related to the devices discussed.