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Background Patients affected by coxarthrosis may be treated surgically with total hip arthroplasty (THA). During the surgical intervention, the hip joint capsule can be completely removed, performing a capsulectomy. Otherwise it's possible to perform a capsulotomy, which allows for capsular conservation. Since there is no scientific evidence demonstrating the superiority of one method over the other, the choice whether to remove or conserve the capsule is at the surgeon's discretion and both procedures are actually accepted. The purpose of our study is to evaluate the differences in functional activities and proprioception in patients who underwent THA and capsulotomy with capsular conservation versus patients who underwent THA with capsulectomy. Methods In order to compare the two surgical techniques of capsulotomy with capsular conservation and capsulectomy, we created a randomized, controlled, double-blind, single-centre, non-pharmacological, interventional, superiority, parallel-group trial. The primary outcome of our study is evaluated using the HOOS scale (Hip disability and Osteoarthritis Outcome Score). Secondary outcomes are: the proprioceptive sensitivity, the postoperative bleeding, the surgical time, the active range of motion, and the ability to walk, sit and stand. The proprioception study is carried out through active and passive repositioning tests. THA is performed through the minimally invasive direct anterior approach. The evaluation tests are carried out in the 15 days preceding the intervention (T0), at 50-day post-operative (T1), and finally at three months after surgery (T2). Discussion Considering that the hip joint capsule is innervated by proprioceptive nerve endings, while the psuedocapsule that replaces the native capsule following a THA with capsulectomy doesn't have any active neurophysiological role, we hypothesize that capsulotomy with capsular conservation at the time of primary THA may lead to better proprioception and therefore better functional recovery. Trial registration ClinicalTrials.gov identifier: NCT02749058. Date of registration: 04/21/2016.

Hematopoietic stem and progenitor cells (HSPC) reside in the bone marrow (BM) niche and serve as a reservoir for mature blood cells throughout life. Aging in the BM is characterized by low‐grade chronic inflammation that could contribute to the reduced functionality of aged HSPC. Mesenchymal stromal cells (MSC) in the BM support HSPC self‐renewal. However, changes in MSC function with age and the crosstalk between MSC and HSPC remain understudied. Here, we conducted an extensive characterization of senescence features in BM‐derived MSC from young and aged healthy donors. Aged MSC displayed an enlarged senescent‐like morphology, a delayed clonogenic potential and reduced proliferation ability when compared to younger counterparts. Of note, the observed proliferation delay was associated with increased levels of SA‐β‐galactosidase (SA‐β‐Gal) and lipofuscin in aged MSC at early passages and a modest but consistent accumulation of physical DNA damage and DNA damage response (DDR) activation. Consistent with the establishment of a senescence‐like state in aged MSC, we detected an increase in pro‐inflammatory senescence‐associated secretory phenotype (SASP) factors, both at the transcript and protein levels. Conversely, the immunomodulatory properties of aged MSC were significantly reduced. Importantly, exposure of young HSPC to factors secreted by aged MSC induced pro‐inflammatory genes in HSPC and impaired HSPC clonogenic potential in a SASP‐dependent manner. Altogether, our results reveal that BM‐derived MSC from aged healthy donors display features of senescence and that, during aging, MSC‐associated secretomes contribute to activate an inflammatory transcriptional program in HSPC that may ultimately impair their functionality.