The present study compares 34 patients with thumb carpometacarpal osteoarthritis (37 thumbs) treated with the Elektra® prosthesis, with 18 patients (18 thumbs) treated with resection-suspension arthroplasty, with an overall mean follow-up period of 13.3 years. Evaluation with disability of arm and shoulder scores, pain via visual analogue scale and range of motion (radial and palmar abduction, and opposition) indicated no significant difference. However, the cohort with a surviving prosthesis showed significantly better subjective grip strength ( p  =  0.04). Complications occurred in 23 of the 37 thumbs in the prosthesis group compared with two in the resection-suspension arthroplasty patients. Seventeen prostheses required revision. At revision operations, we observed local signs of metallosis in 15 of 17 cases. The patients receiving resection-suspension arthroplasty were more satisfied with their treatment ( p  =  0.003). Therefore, we cannot recommend the implantation of Elektra® prosthesis and we speculate that the key problem of aseptic cup loosening is a result of the metal-on-metal bearing. Level of evidence: III

Background: To elucidate the performance of carpometacarpal-I joint prostheses in comparison with the current gold standard treatment, resection-suspension arthroplasty (RA), we conducted a study comparing outcomes of the Ivory prosthesis to those of a cohort of patients receiving RA.Methods: Initially, we had enrolled 34 prosthesis patients and 48 RA patients, of which 5 and 11 were lost to followup. We defined Eaton/Littler stage 3 osteoarthritis, no previous surgery, no concomitant arthrosis, no rheumatic arthritis, no history of trauma and a minimum follow-up period of 2 years as inclusion criteria. We assessed patient demographics, disability of the arm, shoulder, and hand score, pain via visual analogue scale, subjective strength of the thumb, range of motion (radial and palmar abduction and opposition), and patient satisfaction. All occurring complications were recorded.Results: Follow-up included a mean period of 4.5 years (2-7.4) in the prosthesis cohort and 4.1 years (2-6.8) in the RA group. Disability of the arm, shoulder, and hand scores, pain scores, palmar abduction and opposition, and subjective satisfaction showed no significant differences between the two cohorts. Postoperative loss of strength was significantly less in the prosthesis group (p = 0.01). Moreover, we were able to demonstrate better range of motion in terms of radial abduction in the prosthesis group (p = 0.001). The overall complication rate was significantly higher in the prosthesis cohort (41.4% vs. 10.8%) (p = 0.008). Nevertheless, the Ivory prosthesis group showed a survival rate of 93.1%. Conclusion:As the high complication rate is compensated by a better functional outcome (enhanced range of motion and strength), we believe that prosthesis implantation can be a reasonable treatment option for carpometacarpal-I osteoarthritis in a particular patient group. Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

BackgroundMicrosurgical techniques are considered standard procedures in reconstructive surgery. Although microsurgery by itself is defined as surgery aided by optical magnification, there are no guidelines for determining in which clinical situations a microscope or loupe should be used. Therefore, we conducted standardized experiments to objectively assess the impact of optical magnification in microsurgery.MethodsSixteen participants of microsurgical training courses had to complete 2 sets of experiments. Each set had to be performed with an unaided eye, surgical loupes, and a regular operating microscope. The first set of experiments included coaptation of a chicken femoral nerve, and the second set consisted of anastomosing porcine coronary arteries. Evaluation of the sutured nerves and vessels were performed by 2 experienced microsurgeons using an operating microscope.ResultsThe 16 participants of the study completed all of the experiments. The nerve coaptation and vascular anastomoses exercises showed a direct relationship of error frequency and lower optical magnification, meaning that the highest number of microsurgical errors occurred with the unaided eye. For nerve coaptation, there was a strong relationship (P<0.05) between the number of mistakes and magnification, and this relationship was very strong (P<0.01) for vascular anastomoses.ConclusionsWe were able to prove that microsurgical success is directly related to optical magnification. The human eye's ability to discriminate potentially important anatomical structures is limited, which might be detrimental for clinical results. Although not legally mandatory, surgeries such as reparative surgery after hand trauma should be conducted with magnifying devices for achieving optimal patient outcomes.

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