Rare Median Nerve and Digital Nerve Tumor Resection and Distal Nerve Transfers: A Report of 2 Cases.

CASES: We present 2 cases of median nerve reconstruction using distal nerve transfers after resection of unusual benign median nerve tumors. Critical sensation was restored in case 1 by transferring the fourth common digital nerve to first web digital nerves. Thumb opposition was regained by transferring the abductor digiti minimi ulnar motor nerve branch to the recurrent median motor nerve branch. Critical sensation was restored in case 2 by transferring the long finger ulnar digital nerve to the index finger radial digital nerve. CONCLUSION: Distal nerve transfers, even with short grafts, are reliable median nerve deficit treatments, sparing the need for larger autologous nerve grafts and late tendon opponensplasties.

Automated quantification of glenoid bone loss in CT scans for shoulder dislocation surgery planning.

PURPOSE: Estimation of glenoid bone loss in CT scans following shoulder dislocation is required to determine the type of surgery needed to restore shoulder stability. This paper presents a novel automatic method for the computation of glenoid bone loss in CT scans. METHODS: The model-based method is a pipeline that consists of four steps: (1) computation of an oblique plane in the CT scan that best matches the glenoid face orientation; (2) selection of the glenoid oblique CT slice; (3) computation of the circle that best fits the posteroinferior glenoid contour; (4) quantification of the glenoid bone loss. The best-fit circle is computed with newly defined Glenoid Clock Circle Constraints. RESULTS: The pipeline and each of its steps were evaluated on 51 shoulder CT scans (44 patients). Ground truth oblique slice, best-fit circle, and glenoid bone loss measurements were obtained manually from three clinicians. The full pipeline yielded a mean absolute error (%) for the bone loss deficiency of 2.3 ± 2.9 mm (4.67 ± 3.32%). The mean oblique CT slice selection difference was 1.42 ± 1.32 slices, above the observer variability of 1.74 ± 1.82 slices. The glenoid bone loss deficiency measure (%) on the ground truth oblique glenoid CT slice has a mean average error of 0.54 ± 1.03 mm (4.76 ± 3.00%), close to the observer variability of 0.93 ± 1.40 mm (2.98 ± 4.97%). CONCLUSION: Our pipeline is the first fully automatic method for the quantitative analysis of glenoid bone loss in CT scans. The computed glenoid bone loss report may assist orthopedists in selecting and planning surgical shoulder dislocation procedures.

Tranexamic Acid Treatment Reduces Blood Loss After Elective and Semi-Urgent Reverse Total Shoulder Arthroplasty.

Introduction: Post operative blood loss after reverse shoulder arthroplasty (RSA) is associated with the need for blood transfusion and prolonged hospital stay, among other complications. Tranexamic acid (TXA) reduces perioperative blood loss and is effective when delivered systemically or locally. We compared the effects of TXA on perioperative blood loss between elective and semi-urgent RSA. Methods: We retrospectively reviewed patients who underwent either elective or semi-urgent RSA for fracture repair, with and without TXA treatment. Demographics, clinical records, and laboratory results were collected and analyzed to compare peripheral blood hemoglobin concentrations before and after surgery, the need for blood transfusion, and length of hospital stay between the 2 groups. Results: In a cohort of 158 patients, 91 (58%) underwent elective RSA. TXA was administered in 91 (58%) patients from the entire group. TXA administration was associated with a significant decrease in post operative hemoglobin concentration reduction in both the elective and fracture groups (P = .026 and P = .018, respectively), a significant decrease in post operative blood transfusion rates (P = .004 and P = .003, respectively), and a decrease in the need for prolonged hospitalization (P = .038 and P = .009, respectively). Discussion: The local application of TXA during RSA yielded a significant reduction in perioperative blood loss. We showed a significant positive effect of local TXA administration during RSA that is comparable for both elective and semi-urgent patients. Due to the baseline characteristics of fracture patients, their clinical benefits may be more notable. Conclusions: The positive outcomes for surgical patients with the use of TXA during RSA can possibly cause future consideration in clinical practice.

At long-term follow-up many first-time male traumatic shoulder dislocators remain symptomatic.

OBJECTIVES: To assess the status at 13 to 17 years follow-up of a cohort of young male traumatic shoulder dislocators. STUDY DESIGN: Prospective cohort study. METHODS: A prospective study of first-time young male traumatic shoulder dislocators, began in 2004. Subjects were evaluated by the apprehension test after completing rehabilitation 6 to 9 weeks post dislocation. Between March 2021 and July 2022, a telephone questionnaire was administered to ascertain their current shoulder status. Subjects were questioned about avoidance of activities of daily living and sport, participation in sports, current instability, and self-assessed shoulder function by the SANE score. RESULTS: 50/53 (94.3%) of the study subjects, mean age 20.4 years, completed a mean follow-up of 181.8 ±â€¯12 months. The non-redislocation survival was 13% for those with a positive apprehension test and 49% for those with a negative test (p = 0.007). SANE scores were 64.3 ±â€¯23.7 for those with a positive apprehension test and 83.7 ±â€¯19.7 for those with a negative test (p = 0.001). In the year before the follow-up, 33.3% of those treated conservatively and 42.9% treated surgically experienced subluxation (p = 0.5). Fifty-seven percent of those who were treated conservatively and 56% of those who underwent surgery avoided some ADL or sports because of their shoulder. CONCLUSIONS: For young male first time traumatic shoulder dislocators a positive apprehension test after rehabilitation is associated with a high risk for reoccurrence and poorer long-term results. Most subjects were still dealing with shoulder symptoms at long-term follow-up.

The effect of steroid injection into the shoulder on glycemia in patients with type 2 diabetes.

Background: Injections of corticosteroids into or around joints have been reported to increase blood glucose in patients with diabetes due to corticosteroid absorption into the bloodstream. However, the magnitude, duration, and clinical implications of local corticosteroid injections on glycemic control are not clear. The purpose of this study was to evaluate the effects of corticosteroid injection to the shoulder on glycemia in patients with type 2 diabetes mellitus using a continuous glucose monitoring device. Methods: Twenty-five patients with symptomatic shoulder problems and type 2 diabetes mellitus, not treated with insulin, prescribed a corticosteroid injection into the shoulder, were investigated. The patients were connected to a flash glucose monitoring system, which continuously monitored interstitial glucose levels. Data were collected 3 days before injection and for additional 11 days after corticosteroid injection. We analyzed glucose levels in the first 3 days (early postinjection) and on days 4-11 (late postinjection) after the injection and compared them to the preinjection period. The outcome measures included change in the average glucose levels, per patient, between the preinjection and postinjection periods and the differences in the time spent at glucose >180 mg/dL, >250 mg/dL, and >350 mg/dL, per patient, between the preinjection and postinjection periods. Results: The increase in the mean glucose level per patient was statistically significant from 136 mg/dL in the preinjection period to 159 mg/dL in the first 3 days after the injection and returned to normal thereafter. Time at blood glucose >250 mg/dL increased from 4.3% in the preinjection period to 9.5% on the first day after the injection. It then decreased to 7% on day 2, 3.8% on day 3, and 1.4% in the late postinjection period. New onset of glucose levels >350 mg/dL was found in 4 of 25 patients during the early postinjection period. In all 4 patients, the exposure to severe hyperglycemia (>350 mg/dL) was short. None of the patients required intensification of the antidiabetic treatment or insulin injections. Conclusion: Local corticosteroid injection to the shoulder can create a significant, short-term increase in systemic glucose levels in patients with D2DM not treated with insulin. Some of these patients may have periods with glucose above 350 mg %. However, these glycemic changes are short lived and are mostly limited to the 2-3 days after the injection. In addition, none of the patients in our study needed any change in antidiabetic treatment or any medical care after the injection.

Positive Effect of Manipulated Virtual Kinematic Intervention in Individuals with Traumatic Stiff Shoulder: A Pilot Study.

Virtual reality enables the manipulation of a patient's perception, providing additional motivation to real-time biofeedback exercises. We aimed to test the effect of manipulated virtual kinematic intervention on measures of active and passive range of motion (ROM), pain, and disability level in individuals with traumatic stiff shoulder. In a double-blinded study, patients with stiff shoulder following proximal humerus fracture and non-operative treatment were randomly divided into a non-manipulated feedback group (NM-group; n = 6) and a manipulated feedback group (M-group; n = 7). The shoulder ROM, pain, and disabilities of the arm, shoulder and hand (DASH) scores were tested at baseline and after 6 sessions, during which the subjects performed shoulder flexion and abduction in front of a graphic visualization of the shoulder angle. The biofeedback provided to the NM-group was the actual shoulder angle while the feedback provided to the M-group was manipulated so that 10° were constantly subtracted from the actual angle detected by the motion capture system. The M-group showed greater improvement in the active flexion ROM (p = 0.046) and DASH scores (p = 0.022). While both groups improved following the real-time virtual feedback intervention, the manipulated intervention provided to the M-group was more beneficial in individuals with traumatic stiff shoulder and should be further tested in other populations with orthopedic injuries.

Can neck fractures in proximal humeri be predicted by CT-based FEA?

BACKGROUND: Proximal humeri fractures at anatomical and surgical neck (∼5% and ∼50% incidence respectively) are frequent in elderly population. Yet, neither in-vitro experiments nor CT-based finite element analyses (CTFEA) have investigated these in depth. Herein we enhance (Dahan et al., 2019) (addressing anatomical neck fractures) by more experiments and specimens, accounting for surgical neck fractures and explore CTFEA's prediction of humeri mechanical response and yield force. METHODS: Four fresh frozen human humeri were tested in a new experimental configuration inducing surgical neck fractures. Digital image correlation (DIC) provided strains and displacements on humeri surfaces and used to validate CTFEA predictions. CTFEA were enhanced herein to improve the accuracy at the proximal neck: A cortical bone mapping (CBM) algorithm was implemented to overcome insufficient scanning resolution, and a new trabecular material mapping was investigated. RESULTS: The new experimental setting induced impacted surgical neck fractures in all humeri. Excellent DIC to CTFEA correlation in strains was obtained at the shaft (slope 0.984, R2=0.99) and a fair agreement (slope 0.807, R2=0.73) at the neck. CBM algorithm had worsened the correlation, whereas the new material mapping had a negligible influence. Yield loads predictions improved considerably when trabecular yielding (maximum principal strain criterion) was considered instead of surface cortical yielding. DISCUSSION: CTFEA well predicts strains on the shaft and reasonably well on the neck. This enhances former conclusions by past studies conducted using SGs, now also evident by DIC. Yield load prediction for surgical neck fractures (involving crushing of trabecular bone) is predicted better by trabecular failure laws rather than cortex ones. Further FEA studies using trabecular orthotropic constitutive models and failure laws are warrant.

Hyaluronic acid injections for chronic tennis elbow.

BACKGROUND: For most patients, tennis elbow (TE) resolves within 6 months of onset. For those with persistent and painful TE, nonsurgical treatment options are limited. Thousands of studies have tried to find effective treatments for TE but have usually failed. In this study, we tested the hypothesis that injections with hyaluronic acid (HA) would be effective at reducing pain from chronic TE. METHODS: Patients with a minimum of six months of pain from TE and with a pain level of 50 or greater (out of 100) were included in the study. They were randomized equally into one of two treatment groups: injection with HA or injection with saline control. Follow-up was conducted at 3, 6 and 12 months from the initial injection. Both the patient and the examiner at the follow-up visits were blinded to the treatment arm. The primary outcome measure was the visual analog scale (VAS pain) score at one year. Additional outcome measures included the shortened Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH) and Patient Rated Tennis Elbow Evaluation (PRTEE) scores. RESULTS: Eighteen patients were randomized into the HA injection treatment arm, and 17 (94%) completed the study. The average age was 51.9 years, and 10 of the subjects were male. Patients had an average of 28.1 months of pain before entering the study. The VAS score in the HA group decreased from a baseline of 76.4-14.3 at 12 months. All 17 patients in the HA group showed VAS score reductions above the minimal clinically important difference (MCID) of at least 18. The PRTEE score improved from 67 to 28.1. The QuickDASH score improved from 53.7 to 22.5. Follow-up in the saline group was less than 50% and was therefore not used as a comparator. CONCLUSIONS: HA injections yielded significant success in pain relief by three months. Patients continued to improve for the 12-month duration of the study. This study indicates that patients with chronic lateral epicondylitis may benefit from receiving injections of hyaluronic acid rather than having to undergo surgery.

A Multicenter Retrospective Study With a Minimum 5-Year Follow-up Comparing Arthroscopic Bankart Repair and the Latarjet Procedure.

BACKGROUND: Arthroscopic Bankart repair (ABR) and the Latarjet procedure are surgical techniques commonly used to treat anterior shoulder instability. There is no consensus among shoulder surgeons regarding the indications for choosing one over the other. PURPOSE: To compare the results of the Latarjet procedure with those of ABR for the treatment of anterior shoulder instability. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data on all patients who were treated surgically for recurrent anterior shoulder instability between 2006 and 2011 were retrospectively collected at 4 medical centers. The minimum follow-up was 5 years. Data were retrieved from medical charts, and patients were interviewed to assess their level of satisfaction (range, 0-100), functional outcomes (using the American Shoulder and Elbow Surgeons shoulder score; the Subjective Shoulder Value; and the Disabilities of the Arm, Shoulder and Hand score), and quality of life (using the 12-Item Short Form Health Survey [SF-12]). Information on return to sports activities and postoperative level of activity compared with that of the preinjury state, complications, reoperations, and recurrent instability were recorded and evaluated. RESULTS: A total of 242 patients were included. The Latarjet procedure was performed in 27 shoulders, and ABR was performed in 215 shoulders. Patients in the ABR group had significantly higher rates of redislocation (18.5%; P = .05) and subluxation (21.4%; P = .43) but a lower rate of self-reported apprehension (43.0%; P = .05) compared with patients in the Latarjet group (3.7%, 14.8%, and 63.0%, respectively). There were 5 patients in the ABR group who underwent reoperation with the Latarjet procedure because of recurrent instability. The functional scores in the Latarjet group were better than those in the ABR group. The SF-12 physical score was significantly better in the Latarjet group than in the ABR group (98.1 vs 93.9, respectively; P = .01). Patient satisfaction and subjective scores were similar in both groups. CONCLUSION: These results support recently published data on the Latarjet procedure that showed its superiority over ABR in midterm stability (dislocations or subluxations). The contribution of self-reported apprehension to the broad definition of stability is not clear, and apprehension rates were not correlated with satisfaction scores or the recurrence of dislocation or subluxation.

Friedrich Disease: A Case Report.

CASE: A 16-year-old girl presented with pain and swelling of the medial edge of the clavicle. She denied previous trauma and was evaluated by multiple physicians for a possible infection or neoplastic lesion. The patient underwent multiple studies and procedures, including blood tests, imaging studies, and biopsy. After 6 months, a diagnosis of osteochondrosis of the medial clavicle was made. After 1 year of observation, the symptoms resolved. CONCLUSIONS: The rarity of Friedrich disease and the scarcity of literature may lead to delayed diagnosis of this pathology. Awareness of medical personnel of this condition may facilitate accurate diagnosis.

Finite element analyses for predicting anatomical neck fractures in the proximal humerus.

BACKGROUND: Proximal humerus fractures which occur as a result of a fall on an outstretched arm are frequent among the elderly population. The necessity of stabilizing such fractures by surgical procedures is a controversial matter among surgeons. Validating a personalized FE analysis by ex-vivo experiments of humeri and mimicking such fractures by experiments is the first step along the path to determine the necessity of such surgeries. METHODS: Four fresh frozen human humeri were loaded using a new simple experimental setting, so to fracture the humeri at the anatomical neck. Strains on humeri's surfaces predicted by the high order FE analyses (as in Dahan et al., 2016) were compared to the experimental observations to further enhance the validity of the FE analyses. A simplified yield criterion based on a linear elastic analysis and principal strains was used to predict the anatomical neck fracture as observed in the experiment. FINDINGS: An excellent correlation between experimental measured and FE predicted strains was obtained (slope of 0.99 and R2=0.98). All humeri were fractured at the anatomical neck. The predicted yield load was within 10%-20% accuracy. INTERPRETATION: High-order FE analyses reliably predict strains and yield loads in the humeri. Fractures induced by the experimental setting correspond to anatomical neck fractures noticed in practice and classified as AO C1.1-C1.3. Surgical neck fractures, which are most common in clinical practice, could not be realized in the proposed experiments, and a different experimental setting should be sought to obtain them ex-vivo.

Sirt1 Promotes a Thermogenic Gene Program in Bone Marrow Adipocytes: From Mice to (Wo)Men.

Bone marrow adipose tissue (MAT) is influenced by nutritional cues, and participates in whole body energy metabolism. To investigate the role of Sirtuin1 (Sirt1), a key player in metabolism, in MAT, marrow adiposity was evaluated in inbred 5-month-old 129/Sv Sirt1 haplo-insufficient (Sirt1 Δ/+) and wild type (WT) mice. Decreased expression of the thermogenic genes: Prdm16, Pgc1α, Foxc2, Dio2, and ß3AR was detected in whole tibiae derived from Sirt1 Δ/+ compared to WT female mice. Similarly, decreased expression of Prdm16 and Pgc1α was observed in primary bone marrow mesenchymal stem cell (BM-MSC) cultures obtained from Sirt1 Δ/+ compared to WT female mice, suggesting a cell autonomous effect of Sirt1 in BM-MSCs. In vitro, Sirt1 over-expression in the mesenchymal embryonic fibroblast stem cell line C3HT101/2 increased Pgc1α and Prdm16 protein level. Similarly, pharmacologic activation of Sirt1 by SRT3025 increased Foxc2, Pgc1α, Dio2, Tfam, and Cyc1 expression while inhibition of Sirt1 by EX527 down-regulated UCP1 in C3HT101/2 cells. Importantly, in human femoral BM-MSCs obtained from female patients undergoing hip operations for fracture or osteoarthritis, Sirt1 activation by SRT3025 increased PGC1α mRNA and protein level. Blocking sclerostin, an inhibitor of the WNT pathway and a Sirt1 target, by the monoclonal humanized antibody (Sc-AbII), stimulated ß3AR, PRDM16, and UCP1 gene expression, and increased PGC1α protein level. These results show that Sirt1 stimulates a thermogenic gene program in marrow adipocytes in mice and humans via PGC1α activation and sclerostin inhibition. The implications of these findings to bone health, hematopoiesis and whole body energy metabolism remain to be investigated.

Should Patients With Frozen Shoulder Be Screened for Diabetes Mellitus?

BACKGROUND: Idiopathic frozen shoulder (nontraumatic) is commonly encountered in patients between the ages of 35 and 60 years in general orthopaedic practice. While the prevalence of frozen shoulder among the general population is estimated to be between 2% and 4%, a significantly higher prevalence of 10% to 22% has been reported in patients with diabetes mellitus. Since diabetic patients are more prone to develop frozen shoulder than nondiabetics, the question arises as to whether patients diagnosed as having idiopathic frozen shoulder are at greater risk to develop diabetes mellitus and should be routinely screened for this condition. PURPOSE: To compare the prevalence of diabetes mellitus and prediabetes among patients diagnosed with idiopathic frozen shoulder who are not known to have either diabetes mellitus or prediabetic conditions with that of an age-matched group from the general population. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients at a shoulder clinic with a diagnosis of idiopathic frozen shoulder were asked to participate in the study if they were aged between 35 to 60 years and had no known previous diagnosis of diabetes mellitus or prediabetic conditions. These patients underwent a 2-hour oral glucose tolerance test. According to their fasting and 2-hour plasma glucose levels, patients were diagnosed as normal glucose tolerance, prediabetic, or diabetic. Findings were matched with the prevalence in an age-matched general population. RESULTS: Fifty patients completed the test. Four patients with idiopathic frozen shoulder (8%) were found to be prediabetic. No patient was found to be diabetic. All 4 patients reported a history of diabetes in their parents or siblings. CONCLUSION: Patients diagnosed with idiopathic frozen shoulder who are 60 years or younger and are not known diabetics have a similar probability of having diabetes or prediabetes to an age-matched population. No routine diabetic workup is warranted specifically for these patients.

Informal (Hallway) medical consultation in orthopedics-is it as common as it seems?

INTRODUCTION: Informal (hallway) medical consultation is an integral part of the physician's work. As musculoskeletal complaints are very common, orthopedic surgeons stand in the frontline of this practice. Many of these consultations are poorly, if at all, documented, thus imposing a potential medical danger to the patient and a medicolegal danger to the surgeon. We conducted this first study to examine whether this practice is common among the orthopedic surgeons in university hospital. METHODS: In this prospective study, a 2-month record of informal consultations was kept. Six orthopedic surgeons-two joint reconstruction surgeons, one spine surgeon, two arthroscopy and sports medicine surgeons, and a shoulder surgeon participated. They recorded the details of the consulter, whether the consultation was for himself or somebody else, the major complaint, and whether it was a second opinion. All patients were advised to go to the formal orthopedic consultation and no advice or treatment was given. At the end of 2 months, each surgeon was asked to evaluate the percentage of cases he had failed to report. RESULTS: During the 2-month period, 158 people asked for informal (hallway) consultations. 11 of them (7%) were physicians, 114 (72%) were other hospital personnel, 26 (17%) were unrelated to hospital, and 6 (4%) were treated patients' relatives. 93 (59%) of consultations were about the consulter himself and the rest were about a relative or a friend. 41 (26%) were requests for a second opinion. The estimated percentage of not reported cases was 10-40%; when the number of consultations was corrected for these figures, it reached 208 consultations in 2 months. DISCUSSION: In this prospective study, six participating surgeons recorded 158 informal consultation requests in 2 months. If a correction is performed, it averages 0.6 consultations a day for a surgeon (or, if only workdays are counted-0.8 consultations a day). Orthopedic surgeons should be aware of this frequent habit and send these patients to a formal consultation.

Biceps Tenotomy Does not Affect the Functional Outcomes of Patients Treated with Spacer Implantation Due to Massive Irreparable Rotator Cuff Tears.

BACKGROUND: Lesions of the long head of the biceps (LHB) tendon are frequently associated with massive rotator cuff tears (RCT) and may be responsible for shoulder pain and disability. OBJECTIVE: This study aimed to evaluate functional outcomes of arthroscopic biodegradable spacer implantation with or without biceps tenotomy as treatment for persistent shoulder dysfunction and pain due to a massive irreparable RCT. METHODS: A total of 48 patients were implanted with the subacromial spacer using arthroscopic approach with or without biceps tenotomy. All patients were assessed for up to 12 months post-implantation and 18 patients were assessed for at least 24 months (and a maximum of 40 months). Improvement in shoulder function was assessed using Constant score. RESULTS: Subacromial spacer implantation was performed arthroscopically in 48 patients. The mean total Constant score increased from 36 at baseline to 67 points at 12 months post implantation. Patients who underwent LHB tenotomy in addition to the subacromial spacer presented similar improvement of their shoulder function and score compared to the group that was treated with the spacer alone. CONCLUSION: Current study demonstrates that spacer implantation in this patient population provides significant improvement in function and decreases the pain. Additional LHB tenotomy did not influence the postoperative results during the follow-up.

Synovial Lipomatosis of the Glenohumeral Joint.

Synovial lipomatosis (also known as lipoma arborescens) is a rare and benign lesion affecting synovium-lined cavities. It is characterized by hyperplasia of mature fat tissue in the subsynovial layer. Although the most commonly affected site is the knee joint, rarely additional locations such as tendon sheath and other joints are involved. We present a case of synovial lipomatosis of the glenohumeral joint in a 44-year-old man. The clinical data radiological studies and histopathologic results are described, as well as a review of the current literature.

Verified and validated finite element analyses of humeri.

BACKGROUND: Although ~200,000 emergency room visits per year in the US alone are associated with fractures of the proximal humerus, only limited studies exist on their mechanical response. We hypothesise that for the proximal humeri (a) the mechanical response can be well predicted by using inhomogeneous isotropic material properties, (b) the relation between bone elastic modulus and ash density (E(ρash)) is similar for the humerus and the femur, and may be general for long bones, and (c) it is possible to replicate a proximal humerus fracture in vitro by applying uniaxial compression on humerus׳ head at a prescribed angle. METHODS: Four fresh frozen proximal humeri were CT-scanned, instrumented by strain-gauges and loaded at three inclination angles. Thereafter head displacement was applied to obtain a fracture. CT-based high order (p-) finite element (FE) and classical (h-) FE analyses were performed that mimic the experiments and predicted strains were compared to the experimental observations. RESULTS: The E(ρash) relationship appropriate for the femur is equally appropriate for the humeri: predicted strains in the elastic range showed an excellent agreement with experimental observations with a linear regression slope of m=1.09 and a coefficient of regression R(2)=0.98. p-FE and h-FE results were similar for the linear elastic response. Although fractures of the proximal humeri were realised in the in vitro experiments, the contact FE analyses (FEA) were unsuccessful in representing properly the experimental boundary conditions. DISCUSSION: The three hypotheses were confirmed and the linear elastic response of the proximal humerus, attributed to a stage at which the cortex bone is intact, was well predicted by the FEA. Due to a large post-elastic behaviour following the cortex fracture, a new non-linear constitutive model for proximal humerus needs to be incorporated into the FEA to well represent proximal humerus fractures. Thereafter, more in vitro experiments are to be performed, under boundary conditions that may be well represented by the FEA, to allow a reliable simulation of the fracture process.

Cigarette Smoking Is Associated with a Lower Concentration of CD105(+) Bone Marrow Progenitor Cells.

Cigarette smoking is associated with musculoskeletal degenerative disorders, delayed fracture healing, and nonunion. Bone marrow progenitor cells (BMPCs), known to express CD105, are important in local trophic and immunomodulatory activity and central to musculoskeletal healing/regeneration. We hypothesized that smoking is associated with lower levels of BMPC. Iliac bone marrow samples were collected from individuals aged 18-65 years during the first steps of pelvic surgery, under IRB approval with informed consent. Patients with active infectious or neoplastic disease, a history of cytotoxic or radiation therapy, primary or secondary metabolic bone disease, or bone marrow dysfunction were excluded. Separation process purity and the number of BMPCs recovered were assessed with FACS. BMPC populations in self-reported smokers and nonsmokers were compared using the two-tailed t-test. 13 smokers and 13 nonsmokers of comparable age and gender were included. The average concentration of BMPCs was 3.52 × 10(5)/mL ± 2.45 × 10(5)/mL for nonsmokers versus 1.31 × 10(5)/mL ± 1.61 × 10(5)/mL for smokers (t = 3.2, P = 0.004). This suggests that cigarette smoking is linked to a significant decrease in the concentration of BMPCs, which may contribute to the reduced regenerative capacity of smokers, with implications for musculoskeletal maintenance and repair.

Outcome of proximal femoral fractures caused by cycling in the young and mid-aged.

BACKGROUND: Cycling is gaining more popularity both as a sport, on and off-road and also as a means of commute. Cycling accidents harbour significant injury risks including fractures. Proximal femoral fractures are uncommonly associated with cycling in the young adult population. The purpose of this study is to describe this unique pattern of injury as well as the outcome of proximal femoral fractures caused by cycling in the young to mid age population. STUDY DESIGN: retrospective cohort study. 23 fractures in 22 patients were available for analysis. 11 were femoral neck fractures, with six displaced ones, and the rest trochanteric fractures. 21 patients were male patients, and the average age was 42 (range 27-60). All patients but two were operated within 24 h from admission. Radiographic analysis included reduction quality, fracture classification and arthritic changes. Clinical outcome was measured using SF-12 and Oxford hip scores. RESULTS: All fractures healed. Two patients with displaced femoral neck fractures developed avascular necrosis requiring arthroplasty. One patient developed an AVN 2 years after a stable trochanteric fracture but did not require an arthroplasty as of yet. Eight patients required hardware removal due to symptoms. 77% of patients had resumed cycling at the pre-injury level. Mean SF-12 score was 47.1 ± 11.7 for the physical component and 53.7 ± 6.3 for the mental component. Mean oxford hip score as was 40.1 ± 12.2. Radiographic analysis revealed good to acceptable reduction quality. Fracture type, age, cycling type and reduction were not significantly associated with outcome. CONCLUSION: Proximal femoral fractures caused by cycling in young to mid-aged adults are an emerging pattern of injury. Overall favourable result can be expected in the majority of cases, with displaced femoral neck fractures having a risk for AVN. Further delineation of the exact cause for this phenomenon is required with possible intervention for injury prevention.