Around 10 % of long bone fractures show inadequate bone healing resulting in non-union development. A deregulated arginine-citrulline-nitric oxide metabolism caused by a poor nutritional status of the patients is a risk factor for non-unions. Additionally, previous research in mice with a disrupted arginine to citrulline conversion showed delayed healing. The study hypothesis was that stimulating said metabolism could positively influence the healing process through promotion of collagen synthesis and angiogenesis.Adult wild-type mice underwent a femur osteotomy and plate-screw osteosynthesis. Mice were randomly divided into three groups and received daily oral supplementation of arginine, citrulline or 0.9 % saline (control). Body weight and food intake were measured daily. After 14 d, the mice were euthanised and femora collected. Callus formation was assessed by micro-computed tomography and concentrations of amino acids and enzymes in the femora were measured.Only citrulline-treated mice showed significantly increased bridging of the fracture gap when compared to control mice. Femur citrulline and ornithine concentrations were increased in citrulline-treated animals. qPCR showed significantly decreased expression of inflammatory markers, whereas increased expression of angiogenic and collagen-producing factors was observed in citrulline-treated mice. Although food intake did not show any difference between the three groups, animals treated with citrulline showed a weight gain of 0.3 g, compared with a 0.1 g decline in the control group.Daily oral citrulline supplementation stimulated callus formation and improved the inflammatory response, positively contributing to the enhanced healing response. Finally, the increased weight gain pointed toward a better post-operative recovery.

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Aims Besides conventional radiographs, the use of MRI, CT, and bone scintigraphy is frequent in the diagnosis of a fracture of the scaphoid. However, which techniques give the best results remain unknown. The investigation of a new imaging technique initially requires an analysis of its precision. The primary aim of this study was to investigate the interobserver agreement of high-resolution peripheral quantitative CT (HR-pQCT) in the diagnosis of a scaphoid fracture. A secondary aim was to investigate the interobserver agreement for the presence of other fractures and for the classification of scaphoid fracture. Methods Two radiologists and two orthopaedic trauma surgeons evaluated HR-pQCT scans of 31 patients with a clinically-suspected scaphoid fracture. The observers were asked to determine the presence of a scaphoid or other fracture and to classify the scaphoid fracture based on the Herbert classification system. Fleiss kappa statistics were used to calculate the interobserver agreement for the diagnosis of a fracture. Intraclass correlation coefficients (ICCs) were used to assess the agreement for the classification of scaphoid fracture. Results A total of nine (29%) scaphoid fractures and 12 (39%) other fractures were diagnosed in 20 patients (65%) using HR-pQCT across the four observers. The interobserver agreement was 91% for the identification of a scaphoid fracture (95% confidence interval (CI) 0.76 to 1.00) and 80% for other fractures (95% CI 0.72 to 0.87). The mean ICC for the classification of a scaphoid fracture in the seven patients diagnosed with scaphoid fracture by all four observers was 73% (95% CI 0.42 to 0.94). Conclusion We conclude that the diagnosis of scaphoid and other fractures is reliable when using HR-pQCT in patients with a clinically-suspected fracture. Cite this article: Bone Joint J 2020;102-B(4):478–484.

Distal oblique bundle (DOB) reinforcement for treatment of post-traumatic bidirectional instability of the distal radioulnar joint (DRUJ) has previously been reported. The objective of the current study was to assess the incidence of symptomatic graft failure and the need for secondary wrist procedures at a longer follow-up in an updated patient cohort of 27 patients with 28 DOB reinforcement procedures. Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) and patient-rated wrist/hand evaluation (PRWHE) outcome measures were also evaluated. At median 82 months follow-up, pre- to postoperative QuickDASH score improved from a mean of 62 (SD 14) to 31 (SD 22) ( p < 0.01) and PRWHE score from a mean of 67 (SD 17) to 34 (SD 23) ( p < 0.01). Symptomatic graft failure with resultant painful DRUJ instability occurred in four out of 28 procedures, which was better than the published results of alternative surgical options for DRUJ instability. DOB reinforcement presents a relatively safe, effective and durable method for treatment of post-traumatic DRUJ instability. Level of evidence: III