Utilization of MRI in surgical decision making in the shoulder.

BACKGROUND: The aim of this study is to evaluate both the utility of MRI scans and reports used in the current practice routine of shoulder surgeons and their surgical decision-making process. METHODS: Ninety-three shoulder-specialised orthopaedic surgeons of the Canadian Shoulder and Elbow Society (CSES) Orthopaedic Association were surveyed in 2020 anonymously online to help identify the use of MR-imaging and reports in managing shoulder disorders and surgical decision process. RESULTS: Thirty out of 93 (32.25%) CSES fellowship-trained orthopaedic surgeons participated. Respondents request MRI scans in about 55% of rotator cuff (RC) pathology and 48% of shoulder instability cases. Fifty percent of patients with potential RC pathology arrive with a completed MRI scan prior first orthopaedic consult. Their surgical decision is primarily based on patient history (45-55%) and physical examination (23-42%) followed by MRI scan review (2.6-18%), reading MRI reports (0-1.6%) or viewing other imaging (3-23%) depending on the shoulder disease. Ninety percent of surgeons would not decide on surgery in ambiguous cases unless the MR-images were personally reviewed. Respondents stated that shoulder MRI scans are ordered too frequently prior specialist visit as identified in more than 50% of cases depending on pathology. CONCLUSIONS: The decision-making process for shoulder surgery depends on the underlying pathology and patient history. The results demonstrate that orthopaedic surgeons are comfortable reviewing shoulder MRI scans without necessarily reading the MRI report prior to a surgical decision. MRI scans are becoming an increasingly important part of surgical management in shoulder pathologies but should not be used without assessment of patient history and or physical examination.

Histopathology of long head of biceps tendon removed during tenodesis demonstrates degenerative histopathology and not inflammatory changes.

BACKGROUND: The aim of this study is to describe and quantitatively analyze the histopathology of proximal long head biceps (LHB) tendinopathy in patients who have undergone LHB tenodesis. The hypothesis is that severe histopathologic changes of the LHB tendon (LHBT) will most likely be reflected with improved postoperative clinical outcomes. METHODS: The study included patients with isolated LHB tendinopathy or LHB tendinopathy associated with concomitant shoulder pathologies. All had failed conservative treatment (12 months) and had a positive pain response (> 50% reduction) pre-operatively after LHB tendon injection with local anesthetic. All underwent biceps tenodesis procedure between 2008 and 2014. Tendon specimens were collected and histologically analyzed with the semi-quantitative Bonar scoring system. Minimum follow-up time was 1 year. A subset of patients was retrospectively reviewed postoperatively and evaluated employing visual analogue score (VAS), short form survey (SF-12), American Shoulder and Elbow Surgeon (ASES) score, Disability of Arm, Shoulder and Hand (DASH) score, and Oxford Shoulder Score (OSS) and postoperative return to work status. RESULTS: Forty-five biceps tendon specimens were obtained from 44 patients (mean age 50 ± 9.6 years). Histopathological analyses demonstrated advanced degenerative changes with myxoid degeneration and marked collagen disorganization. Minimal inflammation was identified. There were no regional differences in histopathological changes. Clinical outcomes did not correlate significantly with severity of histopathologic changes. CONCLUSIONS: This study confirms that LHBT specimens in patients undergoing tenodesis demonstrate with the use of the Bonar score histopathologic changes of chronic degeneration and not inflammation. The correct histopathologic terminology for this process is LHB tendinosis. The histopathological changes appear uniform throughout the entire length of the LHBT which may inform the nature of the procedure performed.

Shoulder Replacement in the Elderly with Anatomic versus Reverse Total Prosthesis? A Prospective 2-Year Follow-Up Study.

BACKGROUND: In older patients requiring a total shoulder replacement (TSR) and with an intact rotator cuff, there is currently uncertainty on whether an anatomic TSR (aTSR) or a reverse TSR (rTSR) is best for the patient. This comparison study of same-aged patients aims to assess clinical and radiological outcomes of older patients (≥75 years) who received either an aTSR or an rTSR. METHODS: Consecutive patients with a minimum age of 75 years who received an aTSR (n = 44) or rTSR (n = 51) were prospectively studied. Pre- and post-operative clinical evaluations included the ASES score, Constant score, SPADI score, DASH score, range of motion (ROM) and pain and patient satisfaction for a follow-up of 2 years. Radiological assessment identified glenoid and humeral component osteolysis, including notching with an rTSR. RESULTS: We found postoperative improvement for ROM and all clinical assessment scores for both groups. There were significantly better patient reported outcome scores (PROMs) in the aTSR group compared with the rTSR patients (p < 0.001). Both groups had only minor osteolysis on radiographs. No revisions were required in either group. The main complications were scapular stress fractures for the rTSR (n = 11) patients and acromioclavicular joint pain for both groups (aTSR = 2; rTSR = 6). CONCLUSIONS: This study of older patients (≥75 years) demonstrated that an aTSR for a patient with good rotator cuff muscles can lead to a better clinical outcome and less early complications than an rTSR. LEVEL OF EVIDENCE: Level II-prospective cohort study.

Surgical Results of Chronic Distal Biceps Ruptures: A Systematic Review.

BACKGROUND: Distal biceps tendon tears can cause weakness and fatigue with activities requiring elbow flexion and supination. Surgical management of chronic tears (>21 days) is not well described in the literature. PURPOSE: To determine the clinical outcomes of chronic distal biceps repairs and reconstructions. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: We performed a search of Medline (PubMed and Ovid), EMBASE, CINAHL physical therapy, Cochrane Database of Systematic Reviews and Central Register of Controlled Trials, and PubMed Central from inception until September 29, 2020, to identify articles on chronic distal biceps ruptures. The inclusion criteria were studies with at least 1 outcome measure and 10 patients with chronic distal biceps ruptures treated surgically. The quality of the included studies was assessed with the methodological index for nonrandomized studies (MINORS) score. Functional outcomes and complications were reviewed. RESULTS: A total of 12 studies were included after systematic database screenings. The MINORS scores ranged from 5 to 19. There were a total of 1704 distal biceps ruptures, of which 1270 were acute and 434 were chronic. Average follow-up time was 12 months to 5.1 years. Single-incision (n = 3), 2-incision (n = 2), or both (n = 6) surgical techniques were used in these studies. Four studies described the use of autografts, and 4 articles used allografts in the chronic repair. Range of motion, function, and strength outcomes were similar when compared with the contralateral arm. Pain was reduced to minimal levels. Main postoperative complications were of paresthesia (specifically to the lateral antebrachial cutaneous nerve), which were temporary in 69.1% of cases. CONCLUSION: The results of this review indicate that surgical management of chronic distal biceps ruptures demonstrates improvement in outcomes including pain reduction and functional ability. Although there may be a slightly higher immediate complication rate, the functional outcomes remain comparable with those seen in the patient population with acute distal biceps.

Mid-term outcomes of a stemless ceramic head anatomic total shoulder replacement.

BACKGROUND: In an anatomic shoulder replacement (aTSR) good results have been reported with the use of a stemless humeral prosthesis. In vitro a ceramic articulation with polyethylene has been shown to produce less polyethylene wear particles than with metal. This study aims to evaluate clinical and radiographic results of a stemless aTSR with a ceramic head articulating with a polyethylene glenoid component, with mid-term follow-up. METHODS: All patients (n = 92) in this prospective study had an aTSR utilizing a stemless humeral component with a ceramic head and a cemented double pegged cemented polyethylene glenoid component for glenohumeral osteoarthritis. Pre- and postoperative clinical evaluations at 2 years were performed using the ASES score, Constant score, SPADI score, DASH score, VAS pain score, patient satisfaction and range of motion. There was a 5-year evaluation of SPADI, ASES, pain, and satisfaction, plus radiographic assessment of glenoid component radiolucent lines and humeral osteolysis. RESULTS: Seventy-four cases (68.1 ± 7.1 years) had a five-year follow-up and demonstrated active elevation improvement from 91.3° preoperatively to 151.1° (p < 0.001). Further improvement was identified with the ASES from 41.6 to 94.3, the SPADI from 62.9 to 4.3, VAS pain from 5.6 to 0.4 (0-10), and satisfaction levels were at 96%. Sixty-two cases had no glenoid radiolucent lines with a maximum Lazarus score of 2 in one patient. Constant scores, available up to 2 years, improved significantly from 30.3 to 77.9 (p < 0.001). There was one case that required revision for glenoid loosening. CONCLUSIONS: Overall, the 5-year results of this ceramic head prosthesis demonstrated good radiographic and clinical outcomes. TRIAL REGISTRATION: ACTRN12613001183774 . Registered: 29 October 2013 - Retrospectively registered. Australian New Zealand Clinical Trials Registry (ANZCTR).

Targeting repeatability of a less obtrusive surgical navigation procedure for total shoulder arthroplasty.

PURPOSE: Surgical navigation systems have demonstrated improvements in alignment accuracy in a number of arthroplasty procedures, but they have not yet been widely adopted for use in total shoulder arthroplasty (TSA). We believe this is due in part to the obtrusiveness of conventional optical tracking systems, as well as the need for additional intraoperative steps such as calibration and registration. The purpose of this study is to evaluate the feasibility of adapting a less-intrusive dental navigation system for use in TSA. METHODS: We developed a proof-of-concept system based on validated laser-engraved surgical tools recently introduced for use in dental surgery that are calibrated once when manufactured and not recalibrated at time of use. The design also features a notably smaller bone-mounted tracker that can be tracked from a wide range of viewing angles. To assess our system's performance, we modified the dental surgical software to support guidance of a TSA procedure. We then conducted a user study in which three participants with varying surgical experience used the system to drill 30 holes in a glenoid model. Using a coordinate measuring machine, we determined the resulting drilled trajectory and compared this to the pre-planned trajectory. Since we used a model glenoid rather than anatomical specimens, we report on targeting precision rather than overall procedure precision or accuracy. RESULTS: We found targeting precision < 1 mm (standard deviation) for locating the entry hole and < ~ 1° (SD) for both version and inclination. The latter value was markedly lower than the end-to-end angular precision achieved by previously reported TSA navigation systems (approximately 3°-5° SD). CONCLUSION: We conclude that variability during the targeting phase represents a small fraction of the overall variability exhibited by existing systems, so a less obtrusive navigation system for TSA based on laser-engraved tooling is likely feasible, which could improve the uptake rates of surgical navigation for TSA, thereby potentially leading to improved overall surgical outcomes.

Glenoid Component Position Does Not Affect Short-Term Clinical and Radiologic Outcomes in Total Shoulder Arthroplasty.

BACKGROUND: Malpositioning of the glenoid component in total shoulder arthroplasty (TSA) remains the primary source of loosening. The purpose of this study is firstly, to quantify postoperative glenoid component position in patients having a TSA and secondly, to explore whether glenoid component radiolucency is associated with glenoid position, clinical outcomes and patient-reported measures in the short-term (two year) follow-up period. METHODS: This study was a sub-study of a larger clinical trial that included patients who underwent a TSA and who were randomized into two different glenoid types with a minimum two-year follow-up period. Post-operative radiographic assessments (six weeks and two years) were used to measure glenoid component position (version, inclination, offset) and humeral head centering anterior-posterior (AP) and superior-inferior (SI), and to assess glenoid component radiolucent scoring (modified Lazarus). Pre-operative X-rays were used to measure glenoid version, inclination and Walch classification. Patient-reported measures (PROMs) included the EQ-5D health slider and the Western Ontario Osteoarthritis (WOOS) and American Shoulder and Elbow Surgeons (ASES) score and were captured at baseline and two years postoperative. Clinical outcomes including range of motion and complications were also documented. Statistical analysis included t-tests and regression modeling. RESULTS: Ninety-one patients with an average age of 69.9 ± 6.2 years were included in this study. Glenoid component position improved significantly in version (-19.4 ± 8.6° to -17.7 ± 8.5°; p < 0.045) and inclination (11.5 ± 7.1° to 5.9 ± 6.3°; p < 0.00001) from preoperative to six weeks postoperative. Glenoid component offset in SI and humeral head centering in AP remained unchanged throughout the follow-up. Radiolucency (Lazarus classification) was recorded in 21 cases (17.3%) with a Lazarus score of 1 (15 cases) and 2 (6 cases). The EQ-5D health slider, WOOS and ASES, and ROM confirmed continuous improvements from the preoperative scores to the two-year follow-up (p < 0.05). Regression models showed no correlation between glenoid component radiolucency at two years and the postoperative week six glenoid component position; however, female gender was a significant variable. CONCLUSION: Glenoid component changes from its original native glenoid were observed following TSA. Glenoid inclination was improved more than version from baseline, and the humeral head remained well-centered in AP and SI at two years. Radiolucency of the glenoid at two years is not negatively associated with PROMs or component position; however, female gender was identified as a significant predictor and warrants further investigation. Complications are not associated with glenoid position or radiolucency, but longer-term follow-up is required.

Arthroscopic rotator cuff repair without antibiotic prophylaxis does not increase the infection rate.

PURPOSE: Rotator cuff repair is a commonly performed shoulder procedure. In the past 20 years, there has been a shift from mini-open towards arthroscopic repair, and many units exclusively use arthroscopic techniques for rotator cuff surgery. The aim of this study was to find out whether withholding antibiotics had any effect on the infection rate in patients undergoing arthroscopic rotator cuff repair. METHODS: A retrospective analysis of 336 consecutive patients with an arthroscopic rotator cuff repair (RCR) and a minimum 2-year follow-up was performed. The control group received prophylactic antibiotics (controls) and the cases of interest did not receive perioperative antibiotics. A power analysis was performed according to literature regarding infection proportions. The primary outcome was an infection (superficial or deep) in the operated shoulder. RESULTS: There were 336 patients who underwent a RCR. Two-hundred-and-twelve in the control group and 124 in the non-antibiotic group. Average ages were 57.3 ± 12.5 and 56.8 ± 13.2 years in each group, respectively. The follow-up times ranged from 24 to 76 months. Equipment used and surgical techniques were identical, only operating times were statistically different between the groups (control 77.2 ± 41.3 min versus no antibiotic cases 52.9 ± 16.7 min) (p = 0.000009). There was no recorded infection in either group. CONCLUSION: Infection following arthroscopic surgery is uncommon. Small incisions, constant lavage with saline, minimal hardware insertion and short operating times all combine to minimise the risks. Current results point towards no detriment in withholding prophylactic antibiotics in low-risk patients undergoing routine rotator cuff repair surgery. Therefore, judicious use of prophylactic antibiotics in patients undergoing this procedure is advocated to prevent potential harm to those it is administered to. LEVEL OF EVIDENCE: Level III.

COVID-19 pandemic effects on orthopaedic surgeons in British Columbia.

BACKGROUND: COVID-19 was declared a global emergency in the first quarter of 2020. It is has resulted in and continues in over a million deaths worldwide and halted medical systems and particularly elective surgeries worldwide. The aim of this study was to identify the effect of the initial COVID-19 pandemic months on orthopaedic surgeons in British Columbia. METHODS: The study surveyed (June until August 2020) 187 orthopaedic surgeons in British Columbia affiliated with the University of British Columbia or the British Columbia Orthopaedic Association using an online survey to help identify the impact of COVID-19 on patient care, work and personal life. RESULTS: Eighty-seven out of 187 (46.5%) orthopaedic surgeons participated in the online survey. All types of surgeries were completely cancelled for 23 respondents. Elective surgeries were cancelled for most respondents (in-hospital n = 38 and/or ambulatory n = 32). Trauma cases were reduced according to 35 respondents. Outpatient clinics were stopped initially and transferred in virtual clinics (telemedicine). Approximately 40% of respondents were afraid of infecting others (patients, family) and 25% admitted to drink more heavily. Ninety percent of respondents reported an income loss of > 15% (range 0-100%). CONCLUSION: Orthopaedic surgeons and their patients have been significantly affected by the COVID-19 pandemic. Cancellation of surgeries has created an increased backlog of 32,400 orthopaedic surgeries in British Columbia. However, the COVID-19 pandemic has expedited the implementation of telemedicine, which will be a long-lasting benefit in providing healthcare.

Shoulder injections with autologous conditioned serum reduce pain and disability in glenohumeral osteoarthritis: longitudinal observational study.

BACKGROUND: Currently, non-surgical treatments for glenohumeral osteoarthritis (GH-OA) mainly aim to reduce pain. Autologous conditioned serum (ACS), Orthokine, an interleukin-1 inhibitor from the patient's own blood has an anti-inflammatory effect. The objective was to determine whether intra-articular injections of this ACS improved symptoms in patients with GH-OA and delayed the need for a shoulder replacement. METHODS: A total of 36 consecutive patients, 40 shoulders, with OA received up to 6-weekly intra-articular injections of ACS were included. Imaging of GH-OA, range of motion, visual analogue scale (VAS) pain, Shoulder Pain And Disability Index (SPADI), American Shoulder and Elbow Surgeons and Constant scores were assessed pre-injection and post treatment at 3 months. At a minimum of 2 years, VAS and SPADI scores and whether anyone had progressed to a shoulder replacement were recorded. RESULTS: Outcomes 3 months post-ACS injections demonstrated on average statistically significant improvement (P < 0.05) of all measurements: SPADI (54.3 ± 21.5 vs 43.7 ± 23.7), Constant score (50.5 ± 14.1 vs 57.1 ± 17.4), VAS pain (4.8 ± 2.2 vs 3.7 ± 2.4) and range of motion. Of these, 16 shoulders progressed to a shoulder replacement, nine cases quickly (0.6 ± 0.2 years) and seven cases were delayed by 3.1 ± 1.7 years. The other 18 cases had significant improvement in pain, SPADI (58.0 ± 19.6 to 31.8 ± 21.4; P < 0.01) scores and no progression to a shoulder replacement at 3.6 ± 1.0 years follow-up. There was no correlation of glenoid Walch score or joint space with clinical outcome parameters. CONCLUSION: ACS injections in the shoulder joint for OA can reduce pain and disability, and postpone the need for a shoulder replacement.

Bubble Sign to Confirm the Integrity of the Shoulder Rotator Cuff.

The presence of an intra-articular air bubble adjacent to the rotator cuff at the time of diagnostic shoulder arthroscopy will confirm an intact rotator cuff and is helpful in ambiguous cases. After the introduction of the arthroscope, air is pulled owing to negative air pressure in the joint cavity. Fluid inflow is then started after the inflow has been properly flushed of all air. This creates an intra-articular air bubble, which can be found at the top of the capsular-supraspinatus attachment site in cases with an intact rotator cuff. Secondary subacromial positioning of the arthroscope is used to confirm the intact rotator cuff from the bursal side.

Forefoot Reconstruction Following Metatarsal Head Resection Arthroplasty With a Plantar Approach-A 20-Year Follow-Up.

BACKGROUND: Rheumatoid arthritis (RA) can cause significant forefoot disorders. If forefoot deformity and pain are severe, surgical treatment can be considered. The aim of this study was to analyze the long-term outcomes of surgical forefoot correction per Tillmann, which involves resection of the metatarsal heads through a transverse plantar approach for the lesser toes and a dorsomedial approach to the great toe. METHODS: This retrospective study used patient-based questionnaires to analyze the revision rate, pain, use of orthoses, walking ability, forefoot function, and patient satisfaction of patients with RA who had undergone a complete forefoot correction of metatarsophalangeal (MTP) I to V. The study only included participants with RA before the era of biological agents and who were at least 20 years postoperatively. A total of 60 patients who had undergone 100 complete forefoot operations according to Tillmann 24.6 ± 3.5 years ago were included in this study. RESULTS: The data collected showed that 35 reoperations were performed on 26 of the patients. Deformity relapses were often documented for the hallux valgus. More than 60% of the patients were able to wear conventional shoes. The distances the participants were able to walk were significantly increased by wearing shoes when compared with walking barefoot (P < .01). CONCLUSION: While forefoot function remained difficult to assess, the majority of patients were able to use conventional shoes. This long-term follow-up study of patient-reported questionnaires completed more than 20 years after the Tillmann procedure showed that more than 80% of the patients remained satisfied with the outcome. LEVEL OF EVIDENCE: Level IV, retrospective cohort study.

Low physical performance determined by chair rising test muscle mechanography is associated with prevalent fragility fractures.

This study examined associations between physical performance assessed by chair rising test muscle mechanography and DXA T-score as well as body composition in a large patient cohort. Next to various significant interrelationships between these muscle and bone parameters, lower physical performance was associated with prevalent fragility fractures. PURPOSE: Although the interaction between muscle and bone has been demonstrated in various aspects, the clinical focus in the diagnosis of musculoskeletal disorders mainly lies on the skeletal assessments. Accordingly, the association between muscle function, bone mineral density (BMD), and fragility fractures remains to be further elucidated with a feasible muscle assessment in a clinical setting. METHODS: Patient data (2076 patients, 1538 women, 538 men) were evaluated retrospectively from a large dual energy X-ray absorptiometry (DXA) database as well as from chair rising test (CRT) that was performed on a muscle mechanograph. To determine potential predictors of the CRT time and maximum force, a multivariate regression analysis was performed including age, DXA T-score, and body composition indices. Furthermore, CRT results were compared between non-fracture and fracture cases. RESULTS: We determined independent predictors for CRT time such as age, femoral DXA T-score, and total fat mass, whereas CRT force was only influenced by total lean mass. Both women and men with previous fragility fractures displayed a longer CRT time (women p = 0.009, men p = 0.001) and lower CRT force (women p < 0.001, men p < 0.001) than those with no fractures, while no clear differences in CRT results could be detected between normal BMD, osteopenia, and osteoporosis based on DXA T-scores. CONCLUSIONS: Our study demonstrates that in addition to the associations between chair rising time and femoral T-score assessed by DXA, low muscle strength is associated with previous fragility fractures.

Perioperative complications after surgical treatment in degenerative adult de novo scoliosis.

BACKGROUND: Degenerative adult de novo (DAD) scoliosis appears characteristically in the sixth or seventh decade with symptoms of severe back pain and radiculopathy or spinal claudication. The aim of this study was to enhance the knowledge of perioperative complications and detect possible risk factors in this selective DAD scoliosis surgery. METHODS: This retrospective study included only patients with DAD scoliosis undergone correction spondylodesis with previous failure of conservative treatment. Excluded were patients with other types of scoliosis and previous fusion surgeries. Patient epidemiological data, medical comorbidities and treatments were included. Intraoperative data and perioperative complications were documented. Analyses regarding early, late and no complications were undertaken. RESULTS: A total of 92 patients with a mean age of 67.29 ± 7.93 years and clinical follow-up visits of minimum 12 months were included. On average, 5.26 ± 2.24 segments were fused. Early complications (e.g. wound healing defects, paresis, screw loosing) occurred in 23 patients and often required a re-operation. Cardiac arrhythmias, pacemaker and coumarin derivative therapies were associated with increased perioperative complications. The transforaminal lumbar interbody fusion technique was associated with early complications. Adjacent segment failure occurred in 36% and was the major late complication. Twenty patients did not have any complications in the minimum follow-up. CONCLUSIONS: This study analysed a selective DAD scoliosis collective and its' surgical treatment outcomes. It identified numerous perioperative complications (adjacent segment failure, postoperative paresis and epidural hematoma) and multiple possible predisposing risk factors (e.g. operative techniques and anti-coagulation therapies). This here gained information raises awareness in preoperative patient selection and preparation. Further studies in DAD scoliosis and a risk-adjusted patient selection/preparation are needed to improve treatment quality and outcomes.

Is centrally induced alveolar bone loss in a large animal model preventable by peripheral hormone substitution?

OBJECTIVES: Alveolar bone structures are mostly investigated in small animal models. The majority of these studies examined local influences on the alveolar bone, but only a few examined systemic influencing factors. The hypothalamic-pituitary axis is known to be essential for a vital bone balance. The aim of this study was to analyse the effects that selective hormone treatments have on alveolar bone structure and quality in a sheep model for alveolar bone loss, induced by hypothalamic-pituitary disconnection (HPD). METHODS: Thirty sheep were randomly selected into six groups of five each: control (C), ovariectomy-OVX (O), O + HPD (OH), OH with oestrogen treatment (OHE), OH with thyroxine (T4) treatment (OHT), and OH with a combined treatment of oestrogen and thyroxine (OHTE). After OVX and HPD procedures and an additional 9-month observation/treatment period, structural bone analyses of the mandible were performed by contact radiography, micro-CT, and static histomorphometry. RESULTS: The HPD procedure caused structural alveolar bone parameters to decrease significantly compared to controls (C). Treatment with oestrogen (OHE) was protective and bone structure was maintained at baseline levels. Thyroxine treatment (OHT) promoted significant bone loss, but the combined treatment (OHTE) improved bone structure and volume parameters even above baseline levels. CONCLUSIONS: Alveolar bone homeostasis significantly underlies systemic regulatory systems. Centrally induced (HPD) bone loss can be prevented by combined peripheral treatment with oestrogen and thyroxine. CLINICAL RELEVANCE: These results demonstrate the significance of a balanced hormonal regulatory system for steady bone remodelling and maintenance of healthy alveolar bone.

Sheep model for osteoporosis: The effects of peripheral hormone therapy on centrally induced systemic bone loss in an osteoporotic sheep model.

Hypothalamic-pituitary disconnection (HPD) leads to low bone turnover followed by bone loss and reduced biomechanical properties in sheep. To investigate the role of peripheral hormones in this centrally induced systemic bone loss model, we planned a hormone replacement experiment. Therefore, estrogen (OHE), thyroxin (OHT) or a combination of both (OHTE) was substituted in ovariectomized HPD sheep, as both hormones are decreased in HPD sheep and are known to have a significant but yet not fully understood impact on bone metabolism. Bone turnover and structural parameters were analyzed in comparison to different control groups - untreated sheep (C), ovariectomized (O) and ovariectomized+HPD sheep (OH). We performed histomorphometric and HR-pQCT analyses nine months after the HPD procedure, as well as biomechanical testing of all ewes studied. In HPD sheep (OH) the low bone turnover led to a significant bone loss. Treatment with thyroxin alone (OHT) mainly increased bone resorption, leading to a further reduction in bone volume. In contrast, the treatment with estrogen alone (OHE) and the combined treatment with estrogen and thyroxin (OHTE) prevented HPD-induced bone loss completely. In conclusion, peripheral hormone substitution was able to prevent HPD-induced low-turnover osteoporosis in sheep. But only the treatment with estrogen alone or in combination with thyroxin was able to completely preserve bone mass and structure. These findings demonstrate the importance of peripheral hormones for a balanced bone remodeling and a physiological bone turnover.

Deterioration of teeth and alveolar bone loss due to chronic environmental high-level fluoride and low calcium exposure.

OBJECTIVES: Health risks due to chronic exposure to highly fluoridated groundwater could be underestimated because fluoride might not only influence the teeth in an aesthetic manner but also seems to led to dentoalveolar structure changes. Therefore, we studied the tooth and alveolar bone structures of Dorper sheep chronically exposed to very highly fluoridated and low calcium groundwater in the Kalahari Desert in comparison to controls consuming groundwater with low fluoride and normal calcium levels within the World Health Organization (WHO) recommended range. MATERIALS AND METHODS: Two flocks of Dorper ewes in Namibia were studied. Chemical analyses of water, blood and urine were performed. Mineralized tissue investigations included radiography, HR-pQCT analyses, histomorphometry, energy-dispersive X-ray spectroscopy and X-ray diffraction-analyses. RESULTS: Fluoride levels were significantly elevated in water, blood and urine samples in the Kalahari group compared to the low fluoride control samples. In addition to high fluoride, low calcium levels were detected in the Kalahari water. Tooth height and mandibular bone quality were significantly decreased in sheep, exposed to very high levels of fluoride and low levels of calcium in drinking water. Particularly, bone volume and cortical thickness of the mandibular bone were significantly reduced in these sheep. CONCLUSIONS: The current study suggests that chronic environmental fluoride exposure with levels above the recommended limits in combination with low calcium uptake can cause significant attrition of teeth and a significant impaired mandibular bone quality. CLINICAL RELEVANCE: In the presence of high fluoride and low calcium-associated dental changes, deterioration of the mandibular bone and a potential alveolar bone loss needs to be considered regardless whether other signs of systemic skeletal fluorosis are observed or not.

Deficiency of Thrombospondin-4 in Mice Does Not Affect Skeletal Growth or Bone Mass Acquisition, but Causes a Transient Reduction of Articular Cartilage Thickness.

Although articular cartilage degeneration represents a major public health problem, the underlying molecular mechanisms are still poorly characterized. We have previously utilized genome-wide expression analysis to identify specific markers of porcine articular cartilage, one of them being Thrombospondin-4 (Thbs4). In the present study we analyzed Thbs4 expression in mice, thereby confirming its predominant expression in articular cartilage, but also identifying expression in other tissues, including bone. To study the role of Thbs4 in skeletal development and integrity we took advantage of a Thbs4-deficient mouse model that was analyzed by undecalcified bone histology. We found that Thbs4-deficient mice do not display phenotypic differences towards wildtype littermates in terms of skeletal growth or bone mass acquisition. Since Thbs4 has previously been found over-expressed in bones of Phex-deficient Hyp mice, we additionally generated Thbs4-deficient Hyp mice, but failed to detect phenotypic differences towards Hyp littermates. With respect to articular cartilage we found that Thbs4-deficient mice display transient thinning of articular cartilage, suggesting a protective role of Thbs4 for joint integrity. Gene expression analysis using porcine primary cells revealed that Thbs4 is not expressed by synovial fibroblasts and that it represents the only member of the Thbs gene family with specific expression in articular, but not in growth plate chondrocytes. In an attempt to identify specific molecular effects of Thbs4 we treated porcine articular chondrocytes with human THBS4 in the absence or presence of conditioned medium from porcine synovial fibroblasts. Here we did not observe a significant influence of THBS4 on proliferation, metabolic activity, apoptosis or gene expression, suggesting that it does not act as a signaling molecule. Taken together, our data demonstrate that Thbs4 is highly expressed in articular chondrocytes, where its presence in the extracellular matrix is required for articular cartilage integrity.

Age- and Sex-Specific Bone Structure Patterns Portend Bone Fragility in Radii and Tibiae in Relation to Osteodensitometry: A High-Resolution Peripheral Quantitative Computed Tomography Study in 385 Individuals.

BACKGROUND: Age- and sex-specific 3D bone structure patterns in human radii and tibiae were investigated with respect to individuals' osteodensitometric status to unravel associations with site-specific fracture occurrences and underlying loading patterns. METHODS: A sample of 385 patients (121 men and 264 women, age range: 23-91 years) were investigated. The patients were classified according to dual X-ray absorptiometry T-scores in three groups: control (n = 60), osteopenia (n = 160), and osteoporosis (n = 165). Bone architecture and geometry were assessed by high-resolution peripheral quantitative computed tomography of the cortical and trabecular compartments in distal radii and tibiae. RESULTS: We found site-dependent age- and sex-related trends regarding bone architecture and geometry. Females displayed more pronounced age-related changes than males. Specifically, female radii showed both cortical and trabecular structural deterioration with aging, whereas the tibiae demonstrated exclusively cortical deterioration. The mean cortical perimeter revealed a significant age-related increase for both sexes even after adjusting for body height and weight, which suggests that periosteal expansion can be observed in both the tibia and also in the radius. Osteopenia and osteoporosis cases did not reveal higher cortical perimeters in comparison to controls. CONCLUSIONS: The tomographic assessment of bone structure further clarifies the architectural basis for increased bone fragility at distal radii and tibiae with advanced age leading to fracture predilection in females. Our findings may represent a morphological link to epidemiological data on age-dependent fracture incidences. Our data support the presence of periosteal apposition at both skeletal sites despite different loading magnitudes, and challenges the view on periosteal expansion just as a compensatory mechanism to counterbalance bone loss.

Incidence, histopathologic analysis and distribution of tumours of the hand.

BACKGROUND: The aim of this large collective and meticulous study of primary bone tumours and tumourous lesions of the hand was to enhance the knowledge about findings of traumatological radiographs and improve differential diagnosis. METHODS: This retrospective study reviewed data collected from 1976 until 2006 in our Bone Tumour Registry. The following data was documented: age, sex, radiological investigations, tumour location, histopathological features including type and dignity of the tumour, and diagnosis. RESULTS: The retrospective analysis yielded 631 patients with a mean age of 35.9 ± 19.2 years. The majority of primary hand tumours were found in the phalanges (69.7%) followed by 24.7% in metacarpals and 5.6% in the carpals. Only 10.6% of all cases were malignant. The major lesion type was cartilage derived at 69.1%, followed by bone cysts 11.3% and osteogenic tumours 8.7%. The dominant tissue type found in phalanges and metacarpals was of cartilage origin. Osteogenic tumours were predominant in carpal bones. Enchondroma was the most commonly detected tumour in the hand (47.1%). CONCLUSIONS: All primary skeletal tumours can be found in the hand and are most often of cartilage origin followed by bone cysts and osteogenic tumours. This study furthermore raises awareness about uncommon or rare tumours and helps clinicians to establish proper differential diagnosis, as the majority of detected tumours of the hand are asymptomatic and accidental findings on radiographs.