MicroRNAs (miRNAs) are a class of small non-coding RNAs that have emerged as potential predictive, prognostic, and therapeutic biomarkers, relevant to many pathophysiological conditions including limb immobilization, osteoarthritis, sarcopenia, and cachexia. Impaired musculoskeletal homeostasis leads to distinct muscle atrophies. Understanding miRNA involvement in the molecular mechanisms underpinning conditions such as muscle wasting may be critical to developing new strategies to improve patient management. MicroRNAs are powerful post-transcriptional regulators of gene expression in muscle and, importantly, are also detectable in the circulation. MicroRNAs are established modulators of muscle satellite stem cell activation, proliferation, and differentiation, however, there have been limited human studies that investigate miRNAs in muscle wasting. This narrative review summarizes the current knowledge as to the role of miRNAs in the skeletal muscle differentiation and atrophy, synthesizing the findings of published data. Cite this article: Bone Joint Res 2020;9(11):798–807

Aims. The gluteus minimus (GMin) and gluteus medius (GMed) have unique structural and functional segments that may be affected to varying degrees, by end-stage osteoarthritis (OA) and normal ageing. We used data from patients with end-stage OA and matched healthy controls to 1) quantify the atrophy of the GMin and GMed in the two groups and 2) describe the distinct patterns of the fatty infiltration in the different segments of the GMin and GMed in the two groups. Methods. A total of 39 patients with end-stage OA and 12 age- and sex frequency-matched healthy controls were prospectively enrolled in the study. Fatty infiltration within the different segments of the GMin and the GMed was assessed on MRI according to the semiquantitative classification system of Goutallier and normalized cross-sectional areas were measured. Results. The GMin was smaller in the OA-group (p < 0.001) compared to the control group, but there was no group difference in the size of the GMed (p = 0.101). Higher levels of fatty infiltration were identified in the anterior segment of the GMin (p = 0.006) and the anterior (p = 0.006) and middle (p = 0.047) segments of the GMed in the OA group. All subjects in the control group had fatty infiltration of the anterior segment of the GMin, but all except one had no fatty infiltration in the entire GMed. Conclusion. End-stage OA was associated with significant atrophy of the GMin and higher levels of fatty infiltration, particularly in the anterior segments of the GMin and GMed. Minor fatty infiltration of the anterior segment of GMin appears to be a normal part of ageing. Our study has demonstrated different patterns of atrophy and fatty infiltration between patients with end-stage OA and healthy matched peers. Cite this article: Bone Jt Open 2021;2(1):40–47

Tenotomy of the iliopsoas tendon has been described as an effective procedure to treat refractive groin pain induced by iliopsoas tendinitis. However, the procedure forces the rectus femoris to act as the primary hip flexor and little is known about the long-term effects of this procedure on the peri-articular muscle envelope (PAME). Studies suggest that iliopsoas tenotomy results in atrophy of the iliopsoas and decreased hip flexion strength with poorer outcomes, increasing the susceptibility for secondary tendinopathy. The aim of this study is to describe changes in the PAME following psoas release. All patients who presented for clinical examination at our hospital between 2016 and 2021 were retrospectively reviewed. Patients who presented after psoas tenotomy with groin pain and who were unable to actively lift the leg against gravity, were included. Pelvic MRI was taken. Qualitative muscle evaluation was done with the Quartile classification system. Quantitative muscle evaluation was done by establishing the cross-sectional area (CSA). Two independent observers evaluated the ipsi- and contralateral PAME twice. The muscles were evaluated on the level: iliacus, psoas, gluteus minimus-medius-maximus, rectus femoris, tensor fasciae lata, piriformis, obturator externus and internus. For the qualitative evaluation, the intra- and inter-observer reliability was calculated by using kappastatistics. A Bland-Altman analysis was used to evaluate the intra- and inter-observer reliability for the quantitative evaluation. The Wilcoxon test was used to evaluate the changes between the ipsi- and contra-lateral side. 17 patients were included in the study. Following psoas tenotomy, CSA reduced in the ipsilateral gluteus maximus, if compared with the contralateral side. Fatty degeneration occurred in the tensor fascia latae. Both CSA reduction and fatty degeneration was seen for psoas, iliacus, gluteus minimus, piriformis, obturator externus and internus. No CSA reduction and fatty degeneration was seen for gluteus medius and rectus femoris. Conclusions/Discussion. Following psoas tenotomy, the PAME of the hip shows atrophy and fatty degeneration. These changes can lead to detrimental functional problems and may be associated with debilitating rectus femoris tendinopathy. In patients with psoas tendinopathy, some caution is advised when considering an iliopsoas tenotomy

Objectives. Nonunion is one of the most troublesome complications to treat in orthopaedics. Former authors believed that atrophic nonunion occurred as a result of lack of mesenchymal stem cells (MSCs). We evaluated the number and viability of MSCs in site of atrophic nonunion compared with those in iliac crest. Methods. We enrolled five patients with neglected atrophic nonunions of long bones confirmed by clinical examinations and plain radiographs into this study. As much as 10 ml bone marrow aspirate was obtained from both the nonunion site and the iliac crest and cultured for three weeks. Cell numbers were counted using a haemocytometer and vitality of the cells was determined by trypan blue staining. The cells were confirmed as MSCs by evaluating their expression marker (CD 105, CD 73, HLA-DR, CD 34, CD 45, CD 14, and CD 19). Cells number and viability were compared between the nonunion and iliac creat sites. Results. After three weeks, numbers of 6.08×10. 6. cells (. sd. 2.07) and 4.98×10. 6. cells (. sd. 1.15) were obtained from the nonunion site and the iliac crest, respectively, with viability of 87.1% (81.7% to 90.8%) and 89.8% (84.7% to 94.5%), respectively. No differences was found between the two sources of MSCs regarding cells number (p = 0.347) and viability (p = 0.175). Conclusions. Our findings showed the existence of MSCs in the site of atrophic nonunion, at a similar number and viability to those isolated from the iliac crest

Aims. Rotator cuff muscle atrophy and fatty infiltration affect the clinical outcomes of rotator cuff tear patients. However, there is no effective treatment for fatty infiltration at this time. High-intensity interval training (HIIT) helps to activate beige adipose tissue. The goal of this study was to test the role of HIIT in improving muscle quality in a rotator cuff tear model via the β3 adrenergic receptor (β3AR). Methods. Three-month-old C57BL/6 J mice underwent a unilateral rotator cuff injury procedure. Mice were forced to run on a treadmill with the HIIT programme during the first to sixth weeks or seventh to 12th weeks after tendon tear surgery. To study the role of β3AR, SR59230A, a selective β3AR antagonist, was administered to mice ten minutes before each exercise through intraperitoneal injection. Supraspinatus muscle, interscapular brown fat, and inguinal subcutaneous white fat were harvested at the end of the 12th week after tendon tear and analyzed biomechanically, histologically, and biochemically. Results. Histological analysis of supraspinatus muscle showed that HIIT improved muscle atrophy, fatty infiltration, and contractile force compared to the no exercise group. In the HIIT groups, supraspinatus muscle, interscapular brown fat, and inguinal subcutaneous white fat showed increased expression of tyrosine hydroxylase and uncoupling protein 1, and upregulated the β3AR thermogenesis pathway. However, the effect of HIIT was not present in mice injected with SR59230A, suggesting that HIIT affected muscles via β3AR. Conclusion. HIIT improved supraspinatus muscle quality and function after rotator cuff tears by activating systemic sympathetic nerve fibre near adipocytes and β3AR. Cite this article: Bone Joint Res 2023;12(8):455–466

Objectives. To explore the therapeutic potential of combining bone marrow-derived mesenchymal stem cells (BM-MSCs) and hydroxyapatite (HA) granules to treat nonunion of the long bone. Methods. Ten patients with an atrophic nonunion of a long bone fracture were selectively divided into two groups. Five subjects in the treatment group were treated with the combination of 15 million autologous BM-MSCs, 5g/cm. 3. (HA) granules and internal fixation. Control subjects were treated with iliac crest autograft, 5g/cm. 3. HA granules and internal fixation. The outcomes measured were post-operative pain (visual analogue scale), level of functionality (LEFS and DASH), and radiograph assessment. Results. Post-operative pain evaluation showed no significant differences between the two groups. The treatment group demonstrated faster initial radiographic and functional improvements. Statistically significant differences in functional scores were present during the first (p = 0.002), second (p = 0.005) and third (p = 0.01) month. Both groups achieved similar outcomes by the end of one-year follow-up. No immunologic or neoplastic side effects were reported. Conclusions. All cases of nonunion of a long bone presented in this study were successfully treated using autologous BM-MSCs. The combination of autologous BM-MSCs and HA granules is a safe method for treating nonunion. Patients treated with BM-MSCs had faster initial radiographic and functional improvements. By the end of 12 months, both groups had similar outcomes. Cite this article: H.D. Ismail, P. Phedy, E. Kholinne, Y. P. Djaja, Y. Kusnadi, M. Merlina, N. D. Yulisa. Mesenchymal stem cell implantation in atrophic nonunion of the long bones: A translational study. Bone Joint Res 2016;5:287–293. DOI: 10.1302/2046-3758.57.2000587

Purpose of the study: Fatty infiltration and atrophy of rotator cuff muscles is an important prognostic factor for anatomic healing and function after repair. The purpose of this study was to analyse factors influencing the development and progression of the supraspinatus muscle and to search for correlation between infiltration and atrophy. Material and method: Preoperative arthroscans and MRI series for 1688 patients with rotator cuff tears were reviewed. We searched for correlations between fatty infiltration of the supraspinatus muscle and gender, age at imaging, size of the tear, onset (trauma or not), and time from symptom onset to imaging. Fatty infiltration was noted according to the Goutallier classification and on the MRI using the classification adapted by Fuchs. For the statistical analysis, fatty infiltration was considered minor for grades 0 and 1, moderate for grade 2 and severe for grades 3 and 4. Muscle atrophy was assessed using the tangent sign. Results: Fatty infiltration of the supraspinatus increased significantly with the size of the tendon tear (p< 0.0005), time from symptom onset to imaging (lp< 0.0005) and patient age (p< 0.0005). Atrophy increased with number of torn tendons, positive tangent sign was correlated with the grade of fatty infiltration of the supraspinatus (p< 0.0005) and the infraspinatus (p< 0.0005). Moderate and severe fatty infiltration developed a mean 3 and 5 years, respectively, after symptom onset. Discussion: Surgical treatment should be undertaken before the appearance of moderate (grade 2) fatty infiltration and atrophy (positive tangent sign). Conclusion: Moderate fatty infiltration of the supraspinatus develops on average three years after onset of symptoms

Aims: Pathologic studies in foetuses and stillborns with congenital clubfoot have shown atrophy of the musculature of the leg omolateral and incresased fibrous tissues within the muscles belly. Both the triceps surae and the tibialis posterior are mostly involved and their tendons thickened. Atrophy of the musculature of the leg has been described in various clinical studies on congenital clubfoot, but most of the authors believe that atrophy might be secondary to surgical treatment and prolonged immobilization in plaster cast and brace. In our study, we correlated the pathology of foetal leg muscle atrophy with leg muscle atrophy shown by patients with congenital clubfoot. Methods: We investigated the MRI aspects of leg muscles in untreated babies and in children and adults who had been treated soon after birth for unilateral congenital clubfooft. The MRI aspects of the leg muscle in treated patients were compared to those of untreated babies, and to the histopathologic findings of the same muscles in foetuses with congenital clubfoot. Results: The ratio between the muscles of the normal leg and the leg of the clubfoot side was almost the same as measured either on the histological sections of foetuses with congenital clubfoof or in patients before and after treatment, from birth to adulthood. Conclusions: Our study shows that in congenital club-foot leg muscle atrophy is a primitive pathologic finding rather than secondary to treatment

Study design: To investigate the effects of muscle atrophy on back muscle fatigue:. Objective: To assess fibre type atrophy in patients undergoing surgery for pro-lapsed lumbar intervertebral disc, and to determine its effect upon EMG measures of fatigue. Methods: Intra-operative biopsies were obtained from the erector spinae muscles of patients undergoing microdiscectomy. Mean fibre area of type I and II fibres were determined after myosin ATPase staining. Prior to surgery, EMG activity of the erector spinae muscles was recorded bilaterally at T10 and L3 whilst subjects performed the Biering-Sorensen fatigue test. Power spectral analysis indicated the initial median frequency and its rate of decline (median frequency gradient) at each recording site. Fibre type area was compared with the median frequency measures. Subjects: 34 subjects (20 male) with intervertebral disc prolapse. Results: Mean fibre area of type I and II fibres was 5890 ± 1947μm. 2. and 3461 ± 1946μm. 2. in men, and 5144 ± 1692μm. 2. and 1945 ± 1039μm. 2. in women, indicating marked type II fibre atrophy. Type II MFA was positively correlated with initial median frequency at L3 on the operated side (R=0.445) and negatively correlated with the maximum median frequency gradient of the four recording sites (R= −0.430). Conclusion: Type II fibre atrophy influences EMG measures of fatigue. The decrease in initial median frequency with type II fibre atrophy probably reflects a reduced conduction velocity in these small fibres. The less negative median frequency gradient with decreased type II fibre size indicates a lower rate of fatigue which may be explained by an increased contribution to force generation from type I fibres which occupy a greater proportion of the muscle

Background. Load transfer to the bone is believed to be more physiological around the short stem in total hip arthroplasty (THA). However, we found unusual bony remodeling around the shortened tapered femoral stem. Methods. Among 121 consecutive THA using the same shortened tapered stem, 25 hips were excluded because the lateral cortex was already disturbed by previous surgery on the proximal femur. Sixteen hips were also excluded either because direct measurement was unavailable due to improperly taken final radiographs (n=9) or the patient was lost to follow-up (n=7).80 THAs were finally enrolled. Radiographic measurements were made using anteroposterior (AP) radiographs taken immediately and at 2 years after surgery. The thickness of the lateral cortex at the level of the distal end of the coated surface and at 10, 20, 30, and 40 mm proximal to it were measured. Variables for detecting the causative factors were age, gender, BMI, proximal femoral geometry, whether the surgery was done to dominant side, diagnosis leading to surgery, size and offset of the stem, articulation, alignments and operative time. Results. The mean thickness of the lateral cortical bone measured at 10, 20, 30, and 40 mm above the tip of the proximal coating significantly decreased over the course of the 2 years (P<0.001 each). In 46 cases (57.5%), this presented as an intra-cortical osteolytic line (IOL). The mean thickness of the lateral cortex was reduced by more than 10% in 51 cases (63.8%). Sixty-one cases (76.3%) had either an IOL or showed a reduction in lateral cortical thickness greater than 10%. In 37 cases (46.3%), the lateral cortical thickness decreased by more than 20%. The risk of a mean reduction >20% was related to an increased operating time (odds ratio [OR] = 0.981; 0.966 < 95% confidence interval [CI] < 0.996) and lower body mass index (BMI) (OR = 1.216; 1.043 < 95% CI < 1.417). There was one periprosthetic fracture through the atrophied lateral cortex in one patient, The mean reduction of lateral cortex in this patient was 33.2%. Conclusion. Even with THA using a shortened stem, high incidence of proximal stress shielding was noted in the form of lateral cortical atrophy, especially for the patient with low BMI

Aims: We aimed to compare conventional rigid cast immobilization with the semi-rigid functional treatment method with respect to calf muscle atrophy, ankle range of motion (ROM) and patient satisfaction in patients who had acute lateral ligament injury of the ankle. Methods: Sixty patients were randomized into the functional immobilization group (Group SC) or conventional belowthe- knee walking cast (Group R). Muscle atrophy was evaluated by axial Computerized Tomography and ankle ROM were recorded before and after treatment. A brief questionnaire for the evaluation of patient satisfaction was applied after the casts were removed. Results: A reduction in muscle area indicating atrophy was detected for both groups (p< 0.001). However, the atrophy was more pronounced in Group R for anterior and superþcial posterior muscle groups. There was also a reduction in ankle ROM for both groups. The loss of ROM for Group R was more evident and differences between the groups were statistically signiþcant. The patients who were treated with functional immobilization techniques were more satisþed. Mean score for Group SC was 67±12 where as it was 28±7 for Group R (p< 0.001). Conclusions: Functional immobilization has shown better results on patient satisfaction and ankle ROM. Although not statistically signiþcant, functional group also showed better results with respect to muscle atrophy for all muscle groups except the lateral. Regarding the previous literature on the effectiveness of functional immobilisation on ankle stability, this technique additionally brings advantages to the treatment of ankle ligamentous lesions with regard to patient satisfaction and facilitation in rehabilitation

Background: The long term survival of patients with type II and III spinal muscular atrophy differs considerably from patients with Duchenne muscular dystrophy. Despite this, treatment of scoliosis in both groups is often reported together. 1. There are only sporadic reports, all with small numbers, of combined anterior and posterior (two stage) scoliosis surgery in patients with spinal muscular atrophy (SMA). 1. The aim of the current study was to document the peri-operative morbidity, length of stay and correction of deformity in patients with SMA that had two stage surgery and compare them with the patients that had single stage surgery. Methods: A retrospective analysis of data on our consecutive series of patients with SMA. We analysed the data of 31 patients with SMA (16M:15F) who underwent scoliosis surgery between 1996 and 2004. The data collected included SMA type, age at surgery, percentage predicted forced vital capacity(%PFVC), blood loss, duration of surgery, complications, type of surgery undertaken, pre-operative mean Cobb angle ± SD(including bending film Cobb angle ± SD), post-operative Cobb angle ± SD and length of hospital stay. The decision to do single or two stage surgery was based on the history of recurrent chest infection, %PFVC and the stiffness of the curve. Percentage correction of Cobb angle in patients that had two stage surgery compared with those that had single stage posterior surgery. Comparison of post-operative respiratory complications, estimated blood loss, total hours in theatre and mean length of stay between the two groups. Results: There were 27 SMA type II and 4 SMA type III’s with a mean age at surgery of12.5 years (range 7.8 – 17.4). The mean pre-operative Cobb angle of all 31 patients was 89.7° ± 19.7°, the mean bending preoperative Cobb angle was 54° ± 13.3° and the mean post-operative Cobb angle was 33.7° ± 17.3°. Eighteen patients had single stage surgery and 13 had two stage surgery. Twelve out of the thirteen two stage operations had either a thoracotomy or a thoracoabdominal approach. In the patients that had single stage posterior surgery, the mean bending preoperative Cobb angle was 54° ± 13.3° and the mean post-operative Cobb angle was 38.7° ± 19.2°. In the patients that had two stage surgery the mean pre-operative bending Cobb angle was 53.6° ± 11.6° and the post-operative Cobb angle was 25.5° ± 10.8°. The %PFVC in the patients that had single stage and two stage surgery was 39.2 ± 12.8 and 69.2 ± 12.2 respectively. There were 3 respiratory complications in the single stage group and 4 in the two stage group. The average total estimated blood loss (EBL) in the single stage and two stage groups (first and second stage EBL’s combined) were 2433ml and 1902ml respectively. The length of stay for the patients with single stage surgery and two stage surgery was 14.1 ± 4.1 and 18.5 ± 7.4 days respectively. The total surgical hours for the patients with single and two stage surgery were 2.9 ± .6 hrs and 4.8 ± 1.2 hrs respectively. Conclusion: The results of our series would suggest that in a selected group of SMA patients (no history of recurrent chest infection and an acceptable %PFVC) a better immediate deformity correction can be attained with two stage surgery. This has to be weighed up with a greater total EBL and mean length of stay for the patients that had two stage surgery

Aims: To explore the clinical value of foot extensor digi-torum brevis (EDB) muscle in patients with unilateral lumbosacral radiculopathy. Methods: This is a prospective study of 153 patients with low back pain (LBP) and unilateral lumbosacral radiculopathy. The average duration of symptoms was 94 (1–279) days and the average age of patients was 62 (18–75) years. Twenty þve patients had disc herniation with the involvement of L4 nerve root; 32 patients with the L5, and 36 with the S1. There were 31 patients with LBP only. Patients with a history of trauma of the lower legs, repetitive mechanical irritation, or systemic diseases were excluded. In all patients full clinical and neurological examination of the spine was performed. Clinical evaluation of the EDB with resisted dorsal ßexion of the toes was also made. The size and consistency of the EDB muscle was documented and compared with that of the opposite foot. Results: Seventeen patients with L5 and S1 nerve root involvement had isolated atrophy of the EDB muscle as this was compared to the EDB of the opposite side. Conclusions: Clinical evaluation of EDB muscle in patients with unilateral lumbosacral radiculopathy may aid the examiner in understanding the nature and level of the spinal nerve root pathology

Introduction Musculoskeletal injuries, especially fractures, cause reduced limb mobilization. The diminished limb activity promotes muscular atrophy, leading to a slower return to function. Attempts to prevent this atrophy using electrical stimulation have been described after knee reconstruction. The Myospare percutaneous electrical stimulator has been developed to prevent immobilization related atrophy. We undertook this pilot study to assess feasibility, safety, and efficacy of applying electrical stimulation under a cast after ankle fractures. Patients and Methods Between May and December 2004, patients who sustained closed ankle fractures requiring surgery, were recruited to participate in this study. 24 patients took part in the study, sixteen male and eight female. Age range was 18 to 62 years (average 40). All patients underwent open reduction and internal fixation using standard AO technique. A short walking cast was applied after surgery. Patients were randomized into a treatment and a control group. The experimental device was applied in the treatment group for 6 weeks. Patients were examined at 2, 6 and 12 weeks. Evaluation included measurement of calf and ankle circumference, dorsiflexion and plantiflexion, and calculation of the ratio between the injured and uninjured side. At each visit pain intensity was assessed using a visual analog score, and patients filled out a function assessment questionnaire. Analysis was performed using chi square, t-test and repeated measures analysis. Results All patients tolerated the stimulator well. No adverse effects were encountered. There is a trend toward improvement in calf diameter, dorsiflexion and plantarflexion. However, with the small number of patients in this study, no significant difference was apparent. Functional recovery and VAS scores were borderline higher in the treatment group at 12 weeks (p=0.043 and p=.049) when compared to baseline. Discussion The use of the Myospare device under a cast in patients after surgical fixation of ankle fractures has been demonstrated as feasible and safe. In this pilot study a trend toward enhanced recovery was apparent in the treatment group

We examined 52 patients with acute Achilles tendon rupture (ATR), 43 men and 9 women, with a median age of 43 (28–68) years after percutaneous Achilles tendon repair with early functional therapy. 11 patients were treated in a cast (C) and 41 had a specially designed shoed (S). The mean follow-up was 56 (36–95) months. Patients suffering from health problems, which could affect their gait and balance (e.g. OA, spinal stenosis,…), as well as patients suffering from complications postoperatively, were excluded from the study. The mean Hannover Achilles Tendon Score was 81 (50 – 95) points (C = 81, S = 81). Their calf muscle function studied three to eight years after treatment were found to have a significantly impaired dynamic muscle function of the calf muscles when tested in a specially constructed heel-raise test device. The Wilcoxon matched-pairs signed-ranks test showed a two-tailed P value of < 0,0001. The average calf size was 38 (31–46,5) cm on the uninjured side and 36 (32–44,5) cm on the injured side. Only two patients had an equal calf size. Comparing the uninjured and injured side the two-tailed P value was found to be extremely significant < 0,0001. The correlation between the maximum force and functional heel raise testing to the calf size on the injured side was weak with a Spearman correlation coefficient (r) = 0,33–38. There was no difference found between the patients treated in a cast and the patients treated in a shoe with percutaneous Achilles tendon repair and early functional therapy. The principle finding in the present study was that the impact of an ATR is of great importance for the functional outcome than the treatment that is given. The difference in flexion strength and endurance between the injured and the uninjured side remained even after a 56 months follow-up. Therefore, calf size and functional muscle testing is a good tool to test functional outcome after Achilles tendon rupture. However, there was only a weak correlation between the size of atrophy and the amount of force reduction

Aim: To evaluate long term effects of stress shieldieng phenomenon after cementless total hip arthroplasty. Materials-Methods: 80 female pts with OA were randomly allocated in 4 groups according to the type of the cementless stem which was primarily implanted (A-Zwey-Muller,B-Corail,C- Optifix,DAutophor900S). BMD changes of the operated hip (in seven zones), of the operated, contralateral normal hip and of the Lumbar spine were measured pre-op, at 2, 8 and 12 months and every year thereafter. Results: At ten years, 72 pts were available for follow up, all with satisfactory clinical and radiological results with no evidence of polyethylene wear or endosteal lysis. In all groups, the greatest reduction of BMD (calcar atrophyzone 7) was observed at the 2nd post-op year (A:24%, B:8%, C:14.8%, D:18.5%). In all groups, the greatest increase (zone 4) of BMD was also observed at the 2nd post-op year (A7%, B2%, C2.5%, D6.3%). In all groups a similar pattern of slow but progressive recovery of bone mineral density changes after the 3rd year was observed in both zones, approaching baseline values at 10 years in all groups. Preoperative lumbar BMD (osteopenia), body weight, sex and height were not statisticaly correlated to calcar atrophy. Conclusions:We suggest that the clinical and theoretical relevance of stress shielding phenomenon in total hip replacement has been overestimated in the literature

Aims. The aim of this study was to describe a quantitative 3D CT method to measure rotator cuff muscle volume, atrophy, and balance in healthy controls and in three pathological shoulder cohorts. Methods. In all, 102 CT scans were included in the analysis: 46 healthy, 21 cuff tear arthropathy (CTA), 18 irreparable rotator cuff tear (IRCT), and 17 primary osteoarthritis (OA). The four rotator cuff muscles were manually segmented and their volume, including intramuscular fat, was calculated. The normalized volume (NV) of each muscle was calculated by dividing muscle volume to the patient’s scapular bone volume. Muscle volume and percentage of muscle atrophy were compared between muscles and between cohorts. Results. Rotator cuff muscle volume was significantly decreased in patients with OA, CTA, and IRCT compared to healthy patients (p < 0.0001). Atrophy was comparable for all muscles between CTA, IRCT, and OA patients, except for the supraspinatus, which was significantly more atrophied in CTA and IRCT (p = 0.002). In healthy shoulders, the anterior cuff represented 45% of the entire cuff, while the posterior cuff represented 40%. A similar partition between anterior and posterior cuff was also found in both CTA and IRCT patients. However, in OA patients, the relative volume of the anterior (42%) and posterior cuff (45%) were similar. Conclusion. This study shows that rotator cuff muscle volume is significantly decreased in patients with OA, CTA, or IRCT compared to healthy patients, but that only minimal differences can be observed between the different pathological groups. This suggests that the influence of rotator cuff muscle volume and atrophy (including intramuscular fat) as an independent factor of outcome may be overestimated. Cite this article: Bone Jt Open 2021;2(7):552–561

Abstract. Introduction. Skeletal muscle wasting is an important clinical issue following acute traumatic injury, and can delay recovery and cause permanent functional disability particularly in the elderly. However, the fundamental mechanisms involved in trauma-induced muscle wasting remain poorly defined and therapeutic interventions are limited. Objectives. To characterise local and systemic mediators of skeletal muscle wasting in elderly patients following acute trauma. Methods. Experiments were approved by a local NHS Research Ethics Committee and all participants provided written informed consent. Vastus lateralis biopsies and serum samples were taken from human male and female patients shortly after acute trauma injury in lower limbs (n=6; mean age 78.7±4.4 y) and compared to age-matched controls (n=6; mean age 72.6±6.3 y). Atrogenes and upstream regulators (MuRF1; MAFbx; IL6, TNFα, PGC-1α) mRNA expression was assessed in muscle samples via RT-qPCR. Serum profiling of inflammatory markers (e.g. IL6, TNFα, IL1β) was further performed via multiplex assays. To determine whether systemic factors induced by trauma directly affect muscle phenotype, differentiated primary human myotubes were treated in vitro with serum from controls or trauma patients (pooled; n=3 each) in the final 24 hours of differentiation. Cells were then fixed, stained for myogenin and imaged to determine minimum ferret diameter. Statistical significance was determined at P<0.05. Results. There was an increase in skeletal muscle mRNA expression for E3 ligase MAFbx and inflammatory cytokine IL-6 (4.6 and 21.5-fold respectively; P<0.05) in trauma patients compared to controls. Expression of myogenic determination factor MyoD and regulator of mitochondrial biogenesis PGC-1α was lower in muscle of trauma patients vs controls (0.5 and 0.39-fold respectively; P<0.05). In serum, trauma patients showed increased concentrations of circulating pro-inflammatory cytokines IL-6 (14.5 vs. 0.3 pg/ml; P<0.05) and IL-16 (182.7 vs. 85.2 pg/ml; P<0.05) compared to controls. Primary myotube experiments revealed serum from trauma patients induced atrophy (32% decrease in diameter) compared to control serum-treated cells (P<0.001). Conclusion. Skeletal muscle from patients following acute trauma injury showed greater expression of atrophy and inflammatory markers. Trauma patient serum exhibited higher circulating pro-inflammatory cytokine concentrations. Primary human myotubes treated with serum from trauma patients showed significant atrophy compared to healthy serum-treated controls. We speculate a mechanism(s) acting via circulating factors may contribute to skeletal muscle pathology following acute trauma. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Introduction. The presence of pluripotent mesenchymal cells in the periosteum along with the growth factors produced or released following injury provides this tissue with an important role in bone healing. Utilising this property, vascularised periosteal flaps may increase the union rates in recalcitrant atrophic long bone non-union. The novel chimeric fibula-periosteal flap utilises the periosteum raised on an independent periosteal vessel, thus allowing the periosteum to be inset freely around the osteotomy site, improving bone biology. Materials & Methods. Ten patients, with established non-union, underwent fibula-periosteal chimeric flaps (2016–2022) at the Canniesburn Plastic Surgery Unit, UK. Preoperative CT angiography was performed to identify the periosteal branches. A case-control approach was used. Patients acted as their own controls, which obviated patient specific risks for non-union. One osteotomy site was covered by the chimeric periosteal flap and one without. In two patients both the osteotomies were covered using a long periosteal flap. Results. Union rate of 100% (11/11) was noted with periosteal flap osteotomies, versus those without flaps at 28.6% (2/7) (p = 0.0025). Time to union was also reduced in the periosteal flaps at 8.5 months versus 16.75 months in the control group (p = 0.023). Survival curves with a hazard ratio of 4.1, equating to a 4 times higher chance of union with periosteal flaps (log-rank p = 0.0016) was observed. Conclusions. The chimeric fibula-periosteal flap provides an option for atrophic recalcitrant non-unions where use of vascularised fibula graft alone may not provide an adequate biological environment for consolidation

Introduction. The direct anterior approach (DAA) and the posterior approach (PA) are 2 common total hip arthroplasty (THA) exposures. This prospective study quantitatively compared changes in periarticular muscle volume after DAA and PA THA. Materials. Nineteen patients undergoing THA were recruited from the practices of 3 fellowship-trained hip surgeons. Each surgeon performed a single approach, DAA or PA. Enrolled patients underwent a preoperative MRI of the affected hip and two subsequent postoperative MRIs, averaging 9.6 and 24.3 weeks after surgery. Clinical evaluations were done by Harris Hip Score at each follow-up interval. Results. MRIs for 10 DAA and 9 PA patients were analyzed. Groups did not differ significantly with regard to BMI, age, or pre-operative muscle volume. 1 DAA patient suffered a periprosthetic fracture and was excluded from the study. DAA hips showed significant atrophy in the obturator internus (−37.3%) muscle at early follow-up, with persistent atrophy of this muscle at the final follow-up. PA hips showed significant atrophy in the obturator internus (−46.8%) and externus (−16.0%), piriformis (−8.12%), and quadratus femoris muscles (−13.1%) at early follow-up, with persistent atrophy of these muscles at final follow-up. Loss of anterior capsular integrity was present at final follow-up in 2/10 DAA hips while loss of posterior capsular integrity was present in 5/9 PA hips. There was no difference in clinical outcomes. Discussion. This study provides objective evidence that, regardless of surgical approach, a muscle whose tendon is detached from its insertion is likely to demonstrate persistent atrophy 6 months following THA. Although the study was not powered to compare clinical outcomes, it should be noted that no significant difference in patient outcomes were observed. For any tables or figures, please contact the authors directly