Modular Necks and Corrosion - Review of Five Cases

This report updates previous articles and commentary presented on Modular Necks from our Tissue Sparing Implant Study Group. In July 2012 we reported that at two years post-op we had encountered no modular neck taper failures or any signs of fretting corrosion, or pseudo tumors associated with the ARC™ Stem.Today we describe five patients out of five hundred and forty-two who had total hip arthroplasty revision [titanium alloy stem, cobalt-chromium modular neck (c.c.) and c.c. modular head (32 mm or 36 mm), highly-cross-linked polyethylene liner, metal titanium plasma sprayed cementless metal cup]. All patients’ were female and all demonstrated progressive hip pain or late instability. All had debridement of the periarticular soft tissue, stem extraction with new primary length cementless stem replacement. At revision and early follow up all patients are doing well, however, we recommend heighten awareness in all active female patients with modular neck stem junctions.

Late Instability of Bilateral Metal on Metal Hip Resurfacings Due to Progressive Local Tissue Effects

Reports have emerged of local debris consisting of metal particles, with the development of pseudotumours, pelvic masses, lymphocytic perivascular infiltration of tissue around the implant and a neo-capsule tissue reaction in metal on metal (MoM) hip arthroplasty. Steeply-inclined acetabular components a large abduction angle of more than 55 degrees along with a combination of small size component are likely to give rise to higher levels of metal ions. This report describes a case of localised tissue destruction of abductor muscle probably due to the metal debris causing late onset subluxation/dislocation of a hip resurfacing. Late instability of hip resurfacing should raise concerns relating to possible local tissue reaction and muscle damage, and early revision may be recommended.

Combination Jefferson Fracture of C1 and Type II Odontoid Fracture Requiring Surgery: Report of Two Cases

Two cases of simultaneous Jefferson fracture of C1 and Type II odontoid fracture requiring surgical stabilization are reported. One patient required early stabilization because alignment could not be maintained in a halo vest, and the second patient required late stabilization for nonunion after a 3-month period of immobilization in a two-poster cervical brace. Although this uncommon injury can often be managed conservatively, surgical fusion will need to be considered in the setting of early or late instability.

Complex Dislocation of the Metacarpo-Phalangeal Joint of the Index Finger: A Comparison of the Surgical Approaches

Complex dislocation of the index metacarpo-phalangeal joint almost always requires surgical intervention. Controversy exists as to the most suitable surgical approach to reduction: palmar or dorsal. We reviewed four cases and carried out dissections in eight cadaver hands to compare the surgical approaches. The interposed volar plate was found to be the most important obstacle to reduction. Both approaches were successful in obtaining reduction. The dorsal approach was simple and safe, hut necessitated longitudinal division of the volar plate and may carry a theoretical risk of late instability. The palmar approach allows restoration of normal anatomy but the radial neurovascular bundle is always vulnerable.