Visualization of intervertebral disc degeneration in a cadaveric human lumbar spine using microcomputed tomography.

Gross features of disc degeneration (DD) that are associated with back pain include tears in the anulus fibrosus, structural changes of the endplates, and a collapse of the anulus. The aim of this study is the detailed visualization and microstructural characterization of DD using microcomputed tomography (µCT) and a dedicated image post-processing pipeline. In detail, we investigate a cadaveric spine that shows both types of DD between L1 and L2 and between L2 and L3, respectively. The lumbar spine was obtained from a male donor aged 74 years. The complete specimen was scanned using µCT with an isometric voxel size of 93 µm. Subsequently, regions of interest (ROI) were prepared featuring each complete intervertebral disc including the adjacent endplates. ROIs were then additionally scanned with a voxel size of 35 µm and by means of magnetic resonance imaging. The collapsed endplate of the superior L2 showed explicit signs of an endplate-driven degeneration, including bony endplate failures. In contrast, the intervertebral disc between L2 and L3 showed indications of an annulus-driven DD including severe disc height loss and concentric tears. Using µCT we were able to visualize and quantify bone and cartilage features in DD. We showed that in both cases a suite of structural changes accompanies cartilage degeneration, including microstructural bony adaptions to counteract changes in the biomechanical loading regimen.

Torsional stiffness after subtalar arthrodesis using second generation headless compression screws: Biomechanical comparison of 2-screw and 3-screw fixation.

BACKGROUND: Subtalar joint arthrodesis is a common operative treatment for symptomatic subtalar arthrosis. Because excessive relative motion between the talus and calcaneus can delay or prohibit fusion, fixation should be optimized, particularly in patients at risk for subtalar arthrodesis nonunion. Tapered, fully-threaded, variable pitch screws are gaining popularity for this application, but the mechanical properties of joints fixed with these screws have not been characterized completely. We quantified the torsion resistance of 2-screw and 3-screw subtalar joint fixation using this type of screw. METHODS: Ten pairs of cadaveric subtalar joints were prepared for arthrodesis and fixed using Acutrak 2-7.5 screws. One specimen from each pair was fixed with two diverging posterior screws, and the contralateral joint was fixed using two posterior screws and a third screw directed through the anterior calcaneus into the talar neck. Internal and external torsional loads were applied and joint rotation and torsional stiffness were measured at two torque levels. FINDINGS: Internal rotation was significantly less in specimens fixed with three screws. No difference was detectable between 2-screw and 3-screw fixation in external rotation or torsional stiffness in either rotation direction. Both 2-screw and 3-screw fixation exhibited torsion resistance surpassing that reported previously for subtalar joints fixed with two diverging conventional lag screws. INTERPRETATION: Performance of the tapered, fully threaded, variable pitch screws exceeded that of conventional lag screws regardless of whether two or three screws were used. Additional resistance to internal rotation afforded by a third screw placed anteriorly may offer some advantage in patients at risk for nonunion.

The influence of patient age and bone mineral density on osteotomy fixation stability after hallux valgus surgery: A biomechanical study.

BACKGROUND: Oblique osteotomies of the first metatarsal are common surgical treatments for moderate to severe hallux valgus deformity. Osteotomy fixation integrity is important to minimize interfragment motion and maintain correction during healing, and our clinical observations suggest that patient age and bone quality affect fixation stability and ultimately the clinical outcome. Accordingly, this study correlated these patient factors with key mechanical measures of osteotomy angulation resistance in a cadaver hallux valgus correction model. METHODS: Standard Ludloff osteotomies were created in 31 fresh-frozen first metatarsals and fixed with two cannulated, dual-pitch headless screws. Each specimen underwent 1000 plantar-to-dorsal bending loads while monitoring bending stiffness and distal fragment dorsal angulation. Donor age and bone mineral density were then correlated with each mechanical measure at selected cycling increments. FINDINGS: We found significant positive correlation between bone mineral density and osteotomy fixation stiffness for all evaluated load cycles. Moderate negative correlation between bone density and angulation was identified, significant for load cycle 500. There was a weak, nonsignificant negative correlation between donor age and osteotomy bending stiffness, with r ranging from -0.134 to -0.243 between the first and 1000th loads. Little correlation was demonstrable between age and angulation. INTERPRETATION: Because low bone density correlates with decreased osteotomy site stiffness and increased angulation under load, patient compliance and protected weight bearing in the early postoperative phase are particularly important if bone mineral density is exceptionally low. Correspondingly, patients with especially high bone mineral density may be considered candidates for earlier weight bearing and active physical therapy.

A recurrent giant cell tumor of bone treated with denosumab.

Although the giant cell tumor of bone is generally classified as a benign tumor it can rarely metastasize and has a potential risk of local recurrence. We want to report about a female patient who suffered from a recurrence of a giant cell tumor of bone after the implantation of a total endoprosthesis of the knee joint. We have treated her with denosumab, which is a receptor activator of nuclear factor kappa-B ligand inhibitor. In this case report we want to present a new option to treat this kind of neoplasm.

The Weil osteotomy for correction of the severe rheumatoid forefoot.

PURPOSE: In rheumatoid arthritis the metatarsophalangeal (MTP) joints are predominantly affected with resultant metatarsalgia and dislocation. Therapy options include many different surgical procedures with results that are not always satisfying. We present the oblique Weil metatarsal osteotomy as a treatment option for the rheumatic forefoot. METHODS: A total of 216 osteotomies in 63 consecutive patients (72 feet) with a mean age at the time of surgery of 59.3 years and long-standing rheumatoid arthritis were observed prospectively for an average of 57.4 months (minimum 36 months). All patients received a Weil osteotomy of the lesser metatarsals with at least one additional procedure of the forefoot. Patients were evaluated prospectively for clinical outcome by the American Orthopaedic Foot and Ankle Society (AOFAS) lesser MTP-interphalangeal scale and subjective satisfaction. In the radiological evaluation weight-bearing X-rays were analysed for alignment, shortening and union. RESULTS: American Orthopaedic Foot and Ankle Society score increased significantly from 21.9 ± 6.7 to 63.3 ± 9.8 (p < 0.05). The increase was significant for all subgroups regarding pain, function and alignment. All joints were dorsally dislocated preoperatively; a subluxation was present in 13.6 % at follow-up. There was a significant decrease of callositas in 82 %, a decrease in need for orthopaedic shoes in 61 %, a decrease of MTP joint stiffness in 96 % and a relief of severe pain in 97 % of all patients. No metatarsal head dislocation or necrosis, pseudoarthrosis or screw perforation was observed. Of 63 patients, 55 (88 %) subjectively reported excellent or good results. CONCLUSIONS: We conclude that the Weil procedure for lesser metatarsals is a satisfactory method for correcting the rheumatic forefoot and can be recommended as an approach for the future.

Mineralization pattern of vertebral bone material following fragility fracture of the spine.

Little is known whether trabecular bone matrix mineralization is altered at the site of osteoporotic vertebral fractures. Bone mineralization density distribution (BMDD) was assessed in trabecular bone of acute, single-level compression fractures of the spine at various stages of fracture repair using quantitative backscattered electron imaging (qBEI). The grading of the repair stage was performed by histological methods. From 20 patients, who underwent either kyphoplasty (n=18) or vertebroplasty (n=2), a vertebral bone biopsy was taken prior to cement augmentation. Six patients took bisphosphonates (BP) prior to fracture. Three study groups were formed: N1=early-, N2=late-healing and B=BP treatment at late healing stage. In general, all groups had an altered BMDD when compared to historical normative reference data. Mean matrix mineralization (CaMean) was significantly (p<0.001) lower in all groups (N1: -5%, N2: -16%, and B2: -16%). In N2, CaMean was -13.1% (p<0.001) lower than N1. At this stage, deposition of new bone matrix and/or formation of woven bone are seen, which also explains the more heterogeneous matrix mineralization (CaWidth). Moreover, BP treatment (B2) led to a significant reduction in CaWidth (-28.5%, p<0.001), when compared to N2. Bone tissue from vertebrae with acute compression fractures reveals a large variation in matrix mineralization depending on the stage of repair. Bisphosphonate treatment does affect the mineralization pattern of tissue repair. The low mineralization values found in early stage of repair suggest that altered bone material properties may play a role in the occurrence of fragility fractures of the spine.

[Tumors and tumor-like lesions of the foot and ankle - a retrospective analysis of 22 years]. / Tumore und tumorsimulierende Läsionen am Fuss und Sprunggelenk - eine retrospektive Analyse aus 22 Jahren.

Musculoskeletal tumors are rare, with approximately 1% of all malignancies. Only 4% are localized at the foot and ankle. Because of this fact, tumors are often overlooked or even misdiagnosed. During a period of 22 years, 75 tumors (from a total of 1452) were localized at the foot and ankle. Retrospectively, we analyzed the anatomic location of the tumors, the patient's age at the date of diagnosis, and the therapy. Eighteen of 75 tumor cases were malignant, seven cases were with a malignant bone tumor, and 11 cases were with a malignant soft tissue tumor. The most important precondition is a faithful implementation of diagnostic and therapeutic guidelines when treating musculoskeletal tumors. Primary malignant tumors require a wide or radical surgical resection. Whether limb-keeping or ablative procedures should be used also depends on the anatomic location of the tumor, the expectations of the patient, and the functional demands of patients.

The effects of high-dose, long-term alendronate treatment on microarchitecture and bone mineral density of compact and trabecular bone in the proximal femur of adult male rabbits.

INTRODUCTION: Despite the widespread use of bisphosphonates, its effects on normal bone microarchitecture of the proximal femur are still poorly studied. The purpose of this study was to determine the effects of long-term high-dose treatment of alendronate on microstructure and bone mineral density of cancellous, cortical compact and subchondral compact bone of the femoral head and neck region in normal adult male rabbits. MATERIALS AND METHODS: Thirty-two adult, male rabbits were randomized into and were treated with either alendronate or placebo for 6 and 12 months. Micro-QCT measurements were taken in the (1) trabecular region, (2) cortical region of the femoral neck and (3) the subchondral region of the femoral head. RESULTS: In the trabecular region of the femoral head, alendronate treatment significantly increased vBMD at 6 and 12 months (+21.0%, p < 0.05 and +26.8%, p < 0.05, respectively) and BVF (29.6%, p < 0.05 and 35.6%, p < 0.05, respectively) with significantly altered bone microarchitecture when compared with their placebo group; 6- and 12-month alendronate treatment significantly increased the vBMD and thickness and decreased the porosity of the subchondral bone in the femoral head. CONCLUSION: High-dose alendronate treatment led to significant and differential changes in bone microarchitecture in trabecular, cortical and subchondral bone of the proximal femur of adult male rabbits.

Cross-cultural adaptation and validation of the German version of the Western Ontario Shoulder Instability index.

BACKGROUND: The Western Ontario shoulder instability index (WOSI) is a disease-specific quality of life measurement tool with 21 items for patients with shoulder instability. Here, we report on translation and validation of the German version of the WOSI according to international guidelines. PATIENTS AND METHODS: A total of 86 patients in three groups were included in this study. In group I, 24 patients underwent surgical stabilization of the shoulder. Preoperatively and at 12 months post-operatively the WOSI, Rowe score, UCLA, Constant score, and the SF-36 were evaluated. In group II, 25 patients were evaluated 2.6 +/- 1.2 years after sustaining a primary traumatic shoulder dislocation. Group III consisted of 37 healthy men and women with normal, healthy shoulders. Evaluation of Pearson's correlation coefficient between WOSI and Rowe score, UCLA, SF-36 and Constant score and for test-retest reliability was made. Moreover, Cronbach's alpha and floor, and ceiling effects were analyzed. RESULTS: Internal consistency was high (Cronbach's alpha 0.92).Test-retest reliability (Pearson correlation coefficient) was excellent (r = 0.92). The construct validity showed a significant correlation between the WOSI and the scores investigated. There were no floor or ceiling effects for the German WOSI score. CONCLUSION: The German translation of the WOSI is a valid and reliable tool, applicable to outcome studies on patients with shoulder instability.

Rehabilitation after hallux valgus surgery: importance of physical therapy to restore weight bearing of the first ray during the stance phase.

BACKGROUND: Operative treatment of people with hallux valgus can yield favorable clinical and radiographic results. However, plantar pressure analysis has demonstrated that physiologic gait patterns are not restored after hallux valgus surgery. OBJECTIVE: The purpose of this study was to illustrate the changes of plantar pressure distribution during the stance phase of gait in patients who underwent hallux valgus surgery and received a multimodal rehabilitation program. DESIGN: This was a prospective descriptive study. METHODS: Thirty patients who underwent Austin (n=20) and scarf (n=10) osteotomy for correction of mild to moderate hallux valgus deformity were included in this study. Four weeks postoperatively they received a multimodal rehabilitation program once per week for 4 to 6 weeks. Plantar pressure analysis was performed preoperatively and 4 weeks, 8 weeks, and 6 months postoperatively. In addition, range of motion of the first metatarsophalangeal joint was measured, and the American Orthopaedic Foot and Ankle Society (AOFAS) forefoot questionnaire was administered preoperatively and at 6 months after surgery. RESULTS: The mean AOFAS score significantly increased from 60.7 points (SD=11.9) preoperatively to 94.5 points (SD=4.5) 6 months after surgery. First metatarsophalangeal joint range of motion increased at 6 months postoperatively, with a significant increase in isolated dorsiflexion. In the first metatarsal head region, maximum force increased from 117.8 N to 126.4 N and the force-time integral increased from 37.9 N.s to 55.6 N.s between the preoperative and 6-month assessments. In the great toe region, maximum force increased from 66.1 N to 87.2 N and the force-time integral increased from 18.7 N.s to 24.2 N.s between the preoperative and 6-month assessments. LIMITATIONS: A limitation of the study was the absence of a control group due to the descriptive nature of the study. CONCLUSIONS: The results suggest that postoperative physical therapy and gait training may lead to improved function and weight bearing of the first ray after hallux valgus surgery.

Treatment strategies in surgery for rheumatoid arthritis.

Rheumatoid arthritis due to the chronic inflammation of the synovial joints leads to permanent articular cartilage and bone damage. Subsequent instability and mutilation of the joint might happen, and the resulting joint pain and stiffness cause impaired function. The degree of damage is traditionally assessed by radiograph and represents a clinical tool for the evaluation of both disease progression and the effectiveness of interventional therapy. The classification of destruction is therefore done with radiograph and the assessment of the clinical picture. Depending on the radiologic stage different therapy concepts, ranging from conservative to operative, are established. It is the goal of surgery to restore motion and function in a painless joint. Surgery can be done to prevent the joint from further destruction or to replace the joint after resection. Different concepts based on radiologic findings are presented in this review.

Biomechanical comparison of screws and plates for hallux valgus opening-wedge and Ludloff osteotomies.

BACKGROUND: The optimal osteotomy type and fixation method for hallux valgus correction have not been defined. This study examined the mechanical properties of corrective opening-wedge and Ludloff oblique osteotomies under conditions approximating postoperative weight-bearing. METHODS: Twenty-nine pairs of fresh-frozen metatarsals were divided into three groups. In Group 1, headless screws were compared with standard cortical screws for Ludloff osteotomy fixation. In Groups 2 and 3, Ludloff osteotomies fixed with headless screws were compared with opening-wedge osteotomies fixed with non-locking and locking plates, respectively. Constructs underwent dorsally-directed cantilever loading for 1000 cycles. FINDINGS: No significant differences in angulation or stiffness were demonstrable in Group 1. In Group 2, Ludloff/headless screw construct stiffness exceeded non-locking plate construct stiffness. The mean angulation on the 1000th load cycle was greater for plates than for Ludloff/headless screws. In Group 3, locking plate construct stiffness and angulation did not differ from Ludloff/headless screws in early cyclic loading, but fixation failure of the locking plate constructs was common. INTERPRETATION: The results indicate that screw type for Ludloff fixation may be left to surgeon preference and that opening-wedge plates exhibit mechanical properties inferior to that of the Ludloff osteotomy under the tested conditions. Lateral cortex continuity and bone density remain important factors in the performance of opening-wedge osteotomies.

Computer-assisted tibia preparation for total ankle arthroplasty: a cadaveric study.

BACKGROUND: Most surgeons performing total ankle arthroplasty (TAA) suggest that accurate tibial preparation perpendicular to the tibial shaft axis improves outcomes. Recent studies demonstrate that computerized surgical navigation significantly improves the accuracy of tibial preparation in total knee arthroplasty (TKA). METHODS: We performed the tibial preparation for TAA in seven matched pairs of cadaver lower extremities. One set of matched pairs was prepared using the conventional external tibial alignment guide/cutting block from the Scandanavian Total Ankle Replacement system (STAR, Waldemar Link GmbH & Co., Hamburg, Germany) under fluoroscopic guidance. The second set of matched pairs was prepared using the VectorVision((R)) navigation system (BrainLAB, Munich, Germany), with currently available computed tomography (CT)-based TKA software. Pre-operative CT data were used to assess the tibial mechanical axis. In both groups, accuracy of the tibial plafond preparation relative to the tibial shaft axis in both the coronal and sagittal planes was determined by fluoroscopic, radiographic and CT analysis. RESULTS: Mean values of the tibial cut for the set of matched-pair tibiae prepared by the conventional surgical method ranged across the three imaging assessment techniques in the ranges 89.3-89.6 degrees (coronal plane, anteroposterior) and 90.3-90.4 degrees (sagittal plane, lateral). For the computer-navigated set, the values were 89.7-89.9 degrees (coronal) and 89.1-89.4 degrees (sagittal). Comparison between the conventional and computer-navigated tibial measurements were not different at the 95% confidence interval (CI) for CT, fluoroscopy or radiographic assessments. CONCLUSIONS: Our results demonstrate that accuracy of TAA tibial preparation using computer-navigation equals that of the conventional technique performed by a foot and ankle surgeon experienced in TAA. We anticipate that this investigation will encourage the development of computer-navigation applications specific to TAA, with the potential of improving accuracy over conventional methods.