The most common European HINT1 neuropathy variant phenotype and its case studies.

HINT1 is an ubiquitous homodimeric purine phosphoramidase belonging to the histidine-triad superfamily. In neurons, HINT1 stabilizes the interaction of different receptors and regulates the effects of their signaling disturbances. Changes in HINT1 gene are associated with autosomal recessive axonal neuropathy with neuromyotonia. Aim of the study was detailed description of patients' phenotype with HINT1 homozygous NM_005340.7: c.110G>C (p.Arg37Pro) variant. Seven homozygous and three compound heterozygous patients were recruited and evaluated using standardized tests for CMT patients, in four patients' nerve ultrasonography was performed. The median age of symptom onset was 10 years (range 1-20), with initial complaints being distal lower limb weakness with gait impairment, combined with muscle stiffness, more pronounced in the hands than in the legs and worsened by cold. Arm muscles became involved later, presenting with distal weakness and hypotrophy. Neuromyotonia was present in all reported patients and is thus a diagnostic hallmark. Electrophysiological studies demonstrated axonal polyneuropathy. Impaired mental performance was observed in six out of ten cases. In all patients with HINT1 neuropathy, ultrasound examination showed significantly reduced muscle volume as well as spontaneous fasciculations and fibrillations. The nerve cross-sectional areas of the median and ulnar nerves were closer to the lower limits of the normal values. None of the investigated nerves had structural changes. Our findings broaden the phenotype of HINT1-neuropathy and have implications for diagnostics and ultrasonographic evaluation of HINT1-neuropathy patients.

Filling Bone Defects after Hip Arthroplasty Revision Using Hydroxyapatite/ß-tricalcium Phosphate: A Case Report with Long-term Result.

Introduction: The increasing number of primary total hip replacements means that there is an increased need for hip arthroplasty revisions. The periprosthetic fractures which cause bone defects can occur during removal of the femoral component and healing of these fractures can be delayed. In femoral bone defects during revisions, there are no metal augments for filling these defects. Case Report: Fifty-nine-year-old female presented with infected loosening of the left hip non-cemented endoprosthesis 5 years after surgery. The patient underwent removal of endoprosthesis. In 2 months, re-implantation of non-cemented endoprosthesis was performed and biphasic calcium phosphate (BCP) ceramic granules with hydroxyapatite/ß-tricalcium phosphate (HAp/ß-TCP) were implanted in the femoral bone defects. Eleven months following the arthroplasty patient had periprosthetic fracture of the distal third of the left femur. The osteosynthesis was performed and BCP ceramic granules with HAp/ß-TCP were used to fill the bone defect. Long-term follow-up showed very good functional outcome and bone defect healing. Conclusion: The BCP ceramic granules with HAp/ß-TCP material adjusted to the bone defect anatomy, showed effective femoral bone defect and periprosthetic fracture healing in a patient with hip arthroplasty revision and periprosthetic fracture.