Alexander Berth

Effect of transcranial magnetic stimulation on voluntary activation in patients with quadriceps weakness

Joint disease causes weakness and wasting of adjacent muscles, in part because of inability to fully activate these muscles voluntarily. Previous findings suggest that transcranial magnetic stimulation (TMS) paired with muscle contractions enhances maximal voluntary contraction force (MVC) in healthy subjects by improving voluntary activation (VA). The aim of the present study was to evaluate whether such an effect is also present in subjects suffering from diminished muscle force due to decreased VA. Three single TMS over resting motor threshold were applied in 10 patients with a mean age of 62 years after total‐knee arthroplasty either during MVC or during muscle relaxation (control experiment) in a blinded randomized crossover study. MVC and VA were determined using a twitch‐interpolation technique at 1, 15, 30, and 60 min after stimulation. There was a significant effect of TMS on MVC if applied in synchrony with muscle contraction, and this persisted for at least 60 min beyond stimulation. In patients suffering from joint disease, TMS might make physiotherapy more effective. Muscle Nerve, 2005

Anatomic and reverse shoulder prostheses in fracture sequelae of the humeral head

OBJECTIVES Arthroplasty for the proximal humerus problems secondary to fractures is troublesome, because of necrosis of the tubercles and the resulting insufficiency of the rotator cuff. The aim of this study was to investigate whether better results can be achieved with the differential use of anatomic and reverse shoulder prostheses, in comparison to the preoperative status. METHODS Fifty-five patients with secondary fracture prostheses due to sequelae of fractures of the humeral head were followed. Anatomic prostheses were implanted in 36 cases (fracture sequelae types 1 and 2 according to Boileau), and reversed prostheses were implanted in 19 cases (fracture sequelae types 3 and 4). RESULTS The mean scores of the patients improved from 19 to 68 points (anatomic prosthesis) for fracture sequelae types 1 and 2, and from 9 to 47.5 points (reverse prosthesis) for fracture sequelae types 3 and 4. CONCLUSION The differential use of anatomic and reversed shoulder prostheses in secondary fracture treatment leads to an improvement in postoperative results. In fracture sequelae types 1 and 2, the anatomic prosthesis is a better choice. However, in fracture sequelae types 3 and 4 with severe deformities, the reversed prosthesis is clearly superior to the anatomic prosthesis.

The terminal complement pathway is activated in septic but not in aseptic shoulder revision arthroplasties

BACKGROUND The early diagnosis of suspected periprosthetic low-grade infections in shoulder arthroplasties is important for the outcome of the revision surgical procedures. The aim of this study was to investigate new biomarkers of infection in revision shoulder arthroplasties, taking into account the implant design, patient age, and comorbidities. METHODS The study included 33 patients with shoulder arthroplasties undergoing revision surgical procedures. Microbiological diagnostic testing was performed in all cases. C-reactive protein serum levels and white blood cell counts were evaluated, and the periprosthetic tissue was stained immunohistologically for the terminal complement pathway components (C3, C5, and C9) and for CD68 and α-defensin. RESULTS Microbiological diagnostic testing detected a periprosthetic infection in 10 reverse shoulder arthroplasties and in 4 anatomic shoulder arthroplasties, while the remaining 19 shoulder arthroplasties were classified as aseptic. We observed more Staphylococcus epidermidis infections in reverse shoulder arthroplasties and more Staphylococcus aureus infections in anatomic shoulder arthroplasties. The revision rate correlated with pre-existing comorbidities and number of previous surgical procedures. The C-reactive protein values and the incidence of specific periprosthetic radiolucent lines were significantly increased in septic revision cases. We found increased staining for all tested complement factors (C3, C5, and C9) but not for α-defensin and CD68 in septic tissue. The most interesting finding was that C9 separated septic from aseptic tissue with a predictive specificity of 100% and a sensitivity of 88.89%. CONCLUSION We observed a strong correlation between C9 expressions in septic revision tissue. We propose that the terminal complement pathway, especially C9 deposition, may be a potential biomarker to identify septic complications using tissue biopsy specimens.