ABSTRACT
Proximal row carpectomy (PRC) and four-corner arthrodesis (4CA) are the two most commonly performed surgical procedures to treat wrist arthritis. Postoperative strength is one of the criteria for choosing between the two techniques. Some authors believe that strength is correlated with residual carpal height. The goal of this study was to determine if postoperative carpal height was predictive of postoperative strength. This study consisted of two parts: a clinical evaluation of grip strength after 4CA or PRC; anatomical and radiological measurements of carpal height before and after 4CA or PRC. Grip strength was better preserved after PRC (87.5%) than after 4CA (76.1%), when expressed relative to the opposite hand (P=0.053). There was a significant decrease in carpal height for the PRC group with a Youm's index of 0.37 versus 0.50 for the 4CA group (P<0.0001). Our clinical results and analysis of the literature indicate that 4CA is not superior to PRC when it comes to grip strength, whereas carpal height is significantly decreased after PRC. The decreased tendon excursion after PRC is balanced by an increase in joint stresses after 4CA.
Subject(s)
Arthritis/surgery , Arthrodesis/methods , Carpal Bones/anatomy & histology , Carpal Bones/surgery , Hand Strength , Wrist Joint/surgery , Adult , Aged , Arthritis/diagnostic imaging , Biomechanical Phenomena , Carpal Bones/diagnostic imaging , Female , Humans , Male , Middle Aged , Range of Motion, Articular , Scaphoid Bone/diagnostic imaging , Scaphoid Bone/surgery , Treatment Outcome , Wrist Joint/diagnostic imaging , Young AdultABSTRACT
Although the chemical composition of mycobacterial cell walls is well known, the 3D organization of the various constituents is not fully understood. In particular, it is unclear whether the major wall component lipoarabinomannan (LAM) is exposed on the outermost surface or hindered by other constituents such as mycolic acids. To address this pertinent question, we used atomic force microscopy (AFM) with tips bearing anti-LAM antibodies to detect single LAM molecules on Mycobacterium bovis BCG cells. First, we showed the ability of anti-LAM tips to detect isolated, purified LAM molecules. We then mapped the distribution of LAM on mycobacteria, prior to and after treatment with the drug isoniazid. We found that LAM was not exposed on the surface of native cells, pointing to the presence of a homogeneous layer of mycolic acids, whereas it was greatly exposed on isoniazid-treated cells, in agreement with the action mode of the drug. This single-molecule study provides novel insight into the architecture of mycobacterial cell walls and offers promising perspectives for understanding the action modes of antimycobacterial drugs.
