Salib, Christopher G.

ABSTRACTThe current method of measuring arthrofibrosis in live rabbits is critically limited. Specifically, this method involves radioactive fluoroscopy, error‐prone goniometric measurements, and static joint angle outcomes that fail to approximate the compliance of tissues surrounding the joint. This study aims to validate a novel method of capturing the compliance of contracted tissues surrounding the joint without the use of fluoroscopy or animal sacrifice. Surgically induced contractures of one‐hundred and eight rabbits were measured using the current standard of contracture measurement (a pulley system) as well as a newly designed dynamic load cell (DLC) device. The DLC device was highly reliable when compared to the pulley system (r = 0.907, p < 0.001). Finally, the DLC device produced joint stiffness hysteresis curves capable of approximating the compliance of stiff joint tissues, ultimately calculating a mean joint stiffness of 1.57 ± 1.31 N · m · rad−1 (range, 0.33–6.37 N · m · rad−1). In conclusion, the DLC device represents a valid method for measuring joint contractures. Further, the DLC device notably improves current techniques by introducing the capacity to approximate the compliance of contracted tissues in living rabbits. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2186–2192, 2018.

AimsReconstruction of the acetabulum after resection of a periacetabular malignancy is technically challenging and many different techniques have been used with varying success. Our aim was to prepare a systematic review of the literature dealing with these techniques in order to clarify the management, the rate of complications and the outcomes.Patients and MethodsA search of PubMed and MEDLINE was conducted for English language articles published between January 1990 and February 2017 with combinations of key search terms to identify studies dealing with periacetabular resection with reconstruction in patients with a malignancy. Studies in English that reported radiographic or clinical outcomes were included. Data collected from each study included: the number and type of reconstructions, the pathological diagnosis of the lesions, the mean age and follow-up, gender distribution, implant survivorship, complications, functional outcome, and mortality. The results from individual studies were combined for the general analysis, and then grouped according to the type of reconstruction.ResultsA total of 57 studies met the inclusion criteria and included 1700 patients. Most lesions were metastatic (41%), followed by chondrosarcoma (29%), osteosarcoma (10%), Ewing’s sarcoma (7%), and multiple myeloma (2%). The techniques of reconstruction were divided into seven types for analysis: those involving a Harrington reconstruction, a saddle prosthesis, an allograft and allograft prosthesis composite, a pasteurised autograft, a porous tantalum implant, a custom-made prosthesis and a modular hemipelvic reconstruction. The rate of complications was 50%, with infection (14%) and instability (8%) being the most common. Mortality data were available for 1427 patients (84%); 50% had died of disease progression, 23% were alive with disease, and 27% had no evidence of disease at a mean follow-up of 3.4 years (0 to 34).ConclusionBoth the rate of complications and mortality are high following resection of oncological periacetabular lesions and reconstruction. Many types of reconstruction have been used with unique challenges and complications for each technique. Newer prostheses, including custom-made prostheses and porous tantalum implants and augments, have shown promising early functional and radiographic outcomes. Cite this article: Bone Joint J 2018;100-B(1 Supple A):22–30.

AbstractSubstance P (SP), a neurotransmitter released after injury, has been linked to deregulated tissue repair and fibrosis in musculoskeletal tissues and other organs. Although SP inhibition is an effective treatment for nausea, it has not been previously considered as an anti‐fibrotic therapy. Although there are extensive medical records of individuals who have used SP antagonists, our analysis of human registry data revealed that patients receiving these antagonists and arthroplasty are exceedingly rare, thus precluding a clinical evaluation of their potential effects in the context of arthrofibrosis. Therefore, we pursued in vivo studies to assess the effect of SP inhibition early after injury on pro‐fibrotic gene expression and contractures in an animal model of post‐traumatic joint stiffening. Skeletally mature rabbits (n = 24) underwent surgically induced severe joint contracture, while injected with either fosaprepitant (a selective SP antagonist) or saline (control) early after surgery (3, 6, 12, and 24 h). Biomechanical testing revealed that differences in mean contracture angles between the groups were not statistically significant (P = 0.27), suggesting that the drug neither mitigates nor exacerbates joint contracture. However, microarray gene expression analysis revealed that mRNA levels for proteins related to cell signaling, pro‐angiogenic, pro‐inflammatory, and collagen matrix production were significantly different between control and fosaprepitant treated rabbits (P < 0.05). Hence, our study demonstrates that inhibition of SP alters expression of pro‐fibrotic genes in vivo. This finding will motivate future studies to optimize interventions that target SP to reduce the formation of post‐traumatic joint contractures.