Neuromuscular adaptations after osseointegration of a bone-anchored prosthesis in a unilateral transfemoral amputee - a case study

PURPOSE

Many individuals with a lower limb amputation experience problems with the fitting of the socket of their prosthesis, leading to dissatisfaction or device rejection. Osseointegration (OI)- the implantation of a shaft directly interfacing with the remaining bone- is an alternative for these patients. In this observational study, we investigated how bone anchoring influences neuromuscular parameters during balance control in a patient with a unilateral transfemoral amputation.

MATERIAL AND METHODS

Center of pressure (CoP) and electromyography (EMG) signals from muscles controlling the hip and the ankle of the intact leg were recorded during quiet standing six months before and one and a half years after this patient underwent an OI surgery. Results were compared to a control group of nine able-bodied individuals.

RESULTS

Muscle co-activation and EMG intensity decreased after bone anchoring, approaching the levels of able-bodied individuals. Muscle co-activation controlling the ankle decreased in the high-frequency range, and the EMG intensity spectrum decreased in the lower-frequency range for all muscles when vision was allowed. With eyes closed, the ankle extensor muscle showed an increased EMG intensity in the high-frequency range post-surgery. CoP length increased in the mediolateral direction of the amputated leg.

CONCLUSIONS

These findings point to shifts in the patient's neuromuscular profile towards the one of able-bodied individuals.

Is there clinical evidence to support autologous matrix-induced chondrogenesis (AMIC) for chondral defects in the talus? A systematic review and meta-analysis

BACKGROUND

The aim of this study is to systematically review the literature on clinical outcomes of patients who have undergone autologous matrix-induced chondrogenesis (AMIC) for treatment of osteochondral lesions of the talus (OCL) and compare the studies' outcomes.

METHODS

Pubmed and Embase were searched in January 2020 for articles concerning OCL surgery. Studies were included if they had a minimum 1-year follow-up and the primary measures were functional outcomes. The meta-analysis compared the Visual Analogic Score (VAS), the American Orthopedic Foot and Ankle Score (AOFAS), and the Foot Function Index (FFI) between baseline and follow-up of 1-2years, and 3-5years. A random effects model was used to evaluate outcome changes.

RESULTS

The search returned 15 studies, with a total of 492 patients. The VAS improved 4.45 and 4.6 points from baseline to the 1-2year and 3-5yearfollow-up, respectively (p<0.001). AOFAS improved 31.59 and 32.47 points from baseline to the 1-2year and 3-5yearfollow-up, respectively (p<0.001). The FFI showed a significant improvement of 30.93 points from baseline to year 3-5 (p<0.001). A total of 6 patients with revision surgeries have been reported within the follow up period. It was not possible to correlate clinical features like lesion size, surgical approach, and bone marrow stimulation technique to the reported outcome.

CONCLUSION

Surgical treatment of OCL via the AMIC procedure provided significant improvement in the functional outcome and pain scores when compared to the pre-operative values. Improvements were observed up to 5years post-operatively.

Fluoroscopic guided tunnel placement during medial patellofemoral ligament reconstruction is not accurate in patients with severe trochlear dysplasia

PURPOSE

Accurate femoral tunnel placement is of great importance during medial patellofemoral ligament (MPFL) reconstruction. Purpose of the present study was to investigate the influence of trochlear dysplasia on the accuracy of fluoroscopic guided femoral tunnel placement.

METHODS

CT-Scans of 30 knees (five with regular shaped trochlea, 10 with a Type A and five each with a Type B, C, or D trochlear dysplasia) were imported into the image analysis platform MeVisLab. A 3D Bone Volume Rendering (VR) and a virtual lateral radiograph was created. The anatomic femoral MPFL insertion was identified on the 3D VR. On virtual lateral radiographs, the MPFL insertion was identified based on landmarks described by Schöttle et al. using three different perspectives: Best possible overlap of the femoral condyles (BC) and a tangent along posterior border of the posterior femoral cortex (pBC); a tangent along the anterior border of the posterior cortex (aBC); and best possible overlap of the distal part of the posterior femoral cortex (BF). Distances between the anatomic attachment and radiographically obtained insertions were measured on the 3D VR and compared according to the type of trochlear dysplasia.

RESULTS

Significantly lower accuracy of fluoroscopy guided tunnel placement in MPFL reconstruction was found in knees with Type C and D dysplasia. This effect was observed irrespectively from the radiologic perspective (pBC, aBC, and FC). In the pBC view (highest accuracy), the mean distance from the centre of the anatomic MPFL attachment to the radiographically defined location was 4.3 mm in knees without trochlear dysplasia and increased to 4.8 mm in knees with Type A dysplasia, 3.8 mm in knees with Type B dysplasia, 6.7 mm (p < 0.001) in knees with Type C dysplasia, and 7.3 mm (p < 0.001) in knees with Type D dysplasia.

CONCLUSION

Radiographic landmark-based femoral tunnel placement in the pBC view provides highest accuracy in knees with a normal shaped trochlea or low grade trochlear dysplasia. In patients with severe dysplasia, fluoroscopy guided tunnel placement has a low accuracy, exceeding a critical threshold of 5 mm distance to the anatomic MPFL insertion irrespective of the radiographic perspective. In these patients, utilization of anatomic landmarks may be beneficial.

LEVEL OF EVIDENCE

IV.

[Update on the latex allergy topic]

Type I allergies to latex have become an increasing problem in occupational dermatology during the past few years, especially since at least 10% of health care workers are affected. In the Department of Dermatology, University Erlangen-Nuremberg, a 12-fold increase in latex-allergic patients has been documented between 1989 and 1995 with a clear trend to more severe systemic manifestations (from 10.7% in 1989/ 1990 to 44% in 1994/1995). Among the water soluble proteins (molecular weights 2 to 200 kD) which may induce latex allergy, at least 5 are considered as main proteins with known primary structure. In addition some "marker' proteins seem to induce specific IgE antibodies in special risk groups (e.g. 46 kD-protein in medical professions, 14.6 kD- and 27 kD-proteins in children with spina bifida). Cross reactions between latex and several fruits (especially avocado, kiwi, banana and chestnut) in 60 to 70% of latex-allergic patients have to be taken into account when evaluating and counselling affected patients. Most important in prophylaxis is the complete change to powder-free latex gloves in medical institutions, since these gloves usually have a low protein content. Our listing of surgical and examination gloves according to their protein content (as measured by the modified Lowry- and High Pressure Liquid Chromatography method) should be a useful guideline for the choice of suitable gloves.

[Severe side-effects during peritoneal dialysis caused by sorbitol-containing dialysate (author's transl)]

In seven patients with chronic renal failure in an advanced stage 17 episodes of upper abdominal pain, hypertension, vomiting and (in some of them) coma occurred during peritoneal dialysis with sorbitol-containing dialysate. The signs recurred in some of the patients but did not when glucose-containing dialysate of otherwise identical composition was used. Very high levels of sorbitol in CSF and serum were measured in the comatose patients. The precipitating factor is probably a reduced metabolic breakdown of sorbitol in renal failure with preferential intracellular deposition of sorbitol and subsequent cellular oedema. To avoid this dangerous reaction it is necessary to use glucose instead of sorbitol in peritoneal dialysates, despite the technical problems of sterilisation. Where this is not possible, glucose should be added in order to reduce the sorbitol concentration in the dialysate to less than 15g/l.

Dailysate calcium and plasma calcium fractions during and after haemodialysis

Dialysate calcium and plasma calcium fractions during and after haemodialysis: The effect of differenct dialysate Ca concentrations on the plasma Ca fractions was examined in 28 patients. In 10 patients dialysed with a dialysate Ca concentration of 3.0 mEq/l the Ca fractions were determined at the start and end of dialysis. 8 patients were dialysed with dialysate with dialysate Ca of 3.5 mEq/l. In this group the Ca fractions were also estimated in the dialysis-free interval. The third group was dialysed with a dialysate Ca of 4.5 mEq/l. Total calcium and protein-bound calcium rose significantly in all groups. Ionised calcium in the first group was significantly reduced, in the second group it remained constant and in the third group it was significantly raised. Since parathyroid function depends on the plasma ionised calcium it is concluded that a dialysed concentration of 3.0 mEq/l is partly responsible for the pathogenesis of secondary hyperparathyroidism and of renal osteodystophy. In normocalcaemic patients a dialysate Ca concentration of 3.5 to 4.0 mEq/l is optimal. In patients entering long-term haemodialysis treatment with pronounced calcium deficiency symptoms a dialysate Ca of up to 4.5 mEq/l may be indicated for a short period after having normalized the inorganic phosphate levels in order to prevent extraosseous calcification.