The problem with this is that it reduces the potential for future knee revisions. In these cases, current clinical practice is to use an extended implant stem to ensure stability. Defective bone stock requires the use of augments to stabilise the tibial plate. About 27,000 knee replacements are carried annually in UK alone and revision knee surgery accounts for about 10-12% worldwide. Alignment and fixation techniques play an important role in achieving high success rates. Loosening of tibial components has been identified as one of the primary causes of failures in early knee replacement. Total knee replacements (TKR) have been of great interest for over three decades. CONCLUSION: The FDI radiographically reduces subluxation of the thumb CMC joint.Strengthening the FDI may be effective in preventing thumb arthritis. Reduction with FDI activation was 67% and 28%, respectively. The two thumbs with the same degree of subluxation at rest and with stress had subluxation 43% and 63% of articular width. FDI activation reduced subluxation by an average of 80% (20-120). In the 26 thumbs that demonstrated increased subluxation with stress, subluxation while stressed averaged 48% (29-75) of metacarpal articular width. Two thumbs were subluxed at rest but did not further sublux with stress. Three thumbs were not subluxed at rest and did not sublux with stress, consistent with stiff CMC joints. Twenty-six thumbs demonstrated subluxation when stressed and reduction after firing of the FDI. Average maximal voluntary contraction of the FDI was 27N, lateral pinch 81N, and grip strength 347N. Two thumbs were excluded for a positive grind and one for poor radiograph quality. Thirteen right-handed, 1 left-handed, and 3 ambidextrous subjects were included. RESULTS: Seventeen subjects with 34 thumbs including 5 males and 12 females participated. The ratio of radial subluxation to the articular width was calculated. Radial subluxation of the base of the first metacarpal and metacarpal width were measured by 3 blinded surgeons as described by Wolf (2011). Fluoroscopy was used to obtain true AP radiographs of the CMC joint at (1) rest, (2) while stressed without activation of the FDI, and (3) while stressed with activation of the FDI. Using a hand-held manometer, maximal voluntary contraction of the FDI as measured by the Rotterdam Intrinsic Myometer lateral pinch strength, and grip strength were measured. A certified hand therapist performed a grind test on all subjects. Exclusion criteria included positive grind test, pregnancy, and major conditions of ligamentous laxity. METHODS: Subjects at least 18 years old were recruited. We hypothesize that activation of the First Dorsal Interosseous (FDI) muscle will radiographically reduce subluxation of the 1st metacarpal relative to the trapezium. Hypermobility leads to joint subluxation and osteoarthritis secondary to resultant joint incongruity. INTRODUCTION: Hypermobility of the carpometacarpal (CMC) joint is a well described etiological factor in the development of thumb arthritis.
0 Comments
Leave a Reply. |