The mechanical environment in Dupuytren's contracture determines cell contractility and associated MMP-mediated matrix remodeling

Matrix metalloproteinases (MMPs) are expressed in Dupuytren's contracture and play a role in matrix remodeling. We tested the role of tension on contractility and MMP expression in Dupuytren's nodule and cord cells. Cells were subjected to pre-determined loading patterns of known repeatable magnitudes (static load, unloading, and overloading) and tested for MMP gene expression (MMP-1, -2, -9, -13, and TIMP-1, -2) and force generation using a tension-culture force monitor. Matrix remodeling was assessed by addition of cytochalasin D and residual matrix tension was quantified. Nodule compared to cord and control cells demonstrate greater force generation and remodeling (p < 0.05). Nodule cells subjected to a reduced load and overloading led to threefold increase of MMP-1, -2, and -9 compared to static load, whilst cord and control cells only showed a twofold increase of MMP-9. Nodule cells subjected to overloading showed a twofold increase in TIMP-2 expression, whilst cord and control cells showed a twofold increase in TIMP-1 expression. Nodule cells differ from cord cells by increased force generation in response to changes in the mechanical environment and related MMP/TIMP-mediated matrix remodeling. In turn this may lead to permanent matrix shortening and digital contracture. Interventional therapies should be aimed at nodule cells to prevent contraction and subsequent permanent matrix remodeling.

Operating in an eczematous surgical field: don't be rash, delay surgery to avoid infective complications

Prominent ear correction is a common operation. Complication as a result of infection has been quoted at between 3% and 5% [Calder JC, Nasaan A. Morbidity of otoplasty: a review of 562 consecutive cases. Br J Plast Surg 1994;47:170-4 and Jeffery SLA. Complications following correction of prominent ears: an audit review of 122 cases. Br J Plast Surg 1999;52:588-90.]. We present two cases referred for ear reconstruction following catastrophic post-operative infection at the time of pinnaplasty, leaving each patient with significant helical rim deformities. Both patients displayed evidence of active post-auricular eczema at the time of their primary surgery. Dermatological research has highlighted the increased colonisation of Staphylococcus aureus in particular within areas of atopic eczema in comparison to normal skin. We advise delaying ear surgery in the presence of a rash in view of the potentially devastating complications that may result. This approach may be extended to all cutaneous surgery where treatment of the rash is advocated prior to embarking on an elective surgical procedure.

Variations in the normal anatomy of the collateral ligaments of the human elbow joint

The variations which occur in the medial and lateral ligament complexes of the elbow were investigated. These occurred frequently with the standard appearances occurring in no more than half the specimens on the medial side and one quarter of those on the lateral side. Surgeons who regularly perform elbow arthroplasty must be aware of these considerations, especially with the introduction of unconstrained prostheses which rely upon the ligament complex for their postoperative stability.