Showing papers by "Georg Osterhoff published in 2016"

Bone mechanical properties and changes with osteoporosis.

Abstract: This review will define the role of collagen and within-bone heterogeneity and elaborate the importance of trabecular and cortical architecture with regard to their effect on the mechanical strength of bone. For each of these factors, the changes seen with osteoporosis and ageing will be described and how they can compromise strength and eventually lead to bone fragility.

The Radiographic Union Score for Hip (RUSH) Identifies Radiographic Nonunion of Femoral Neck Fractures

Abstract: Background The Radiographic Union Score for Hip (RUSH) is a previously validated outcome instrument designed to improve intra- and interobserver reliability when describing the radiographic healing of femoral neck fractures. The ability to identify fractures that have not healed is important for defining nonunion in clinical trials and predicting patients who will likely require additional surgery to promote fracture healing. We sought to investigate the utility of the RUSH score to define femoral neck fracture nonunion.

Cement Augmentation in Sacroiliac Screw Fixation Offers Modest Biomechanical Advantages in a Cadaver Model

Abstract: Sacroiliac screw fixation in elderly patients with pelvic fractures is prone to failure owing to impaired bone quality. Cement augmentation has been proposed as a possible solution, because in other anatomic areas this has been shown to reduce screw loosening. However, to our knowledge, this has not been evaluated for sacroiliac screws. We investigated the potential biomechanical benefit of cement augmentation of sacroiliac screw fixation in a cadaver model of osteoporotic bone, specifically with respect to screw loosening, construct survival, and fracture-site motion. Standardized complete sacral ala fractures with intact posterior ligaments in combination with ipsilateral upper and lower pubic rami fractures were created in osteoporotic cadaver pelves and stabilized by three fixation techniques: sacroiliac (n = 5) with sacroiliac screws in S1 and S2, cemented (n = 5) with addition of cement augmentation, and transsacral (n = 5) with a single transsacral screw in S1. A cyclic loading protocol was applied with torque (1.5 Nm) and increasing axial force (250–750 N). Screw loosening, construct survival, and sacral fracture-site motion were measured by optoelectric motion tracking. A sample-size calculation revealed five samples per group to be required to achieve a power of 0.80 to detect 50% reduction in screw loosening. Screw motion in relation to the sacrum during loading with 250 N/1.5 Nm was not different among the three groups (sacroiliac: 1.2 mm, range, 0.6–1.9; cemented: 0.7 mm, range, 0.5–1.3; transsacral: 1.1 mm, range, 0.6–2.3) (p = 0.940). Screw subsidence was less in the cemented group (3.0 mm, range, 1.2–3.7) compared with the sacroiliac (5.7 mm, range, 4.7–10.4) or transsacral group (5.6 mm, range, 3.8–10.5) (p = 0.031). There was no difference with the numbers available in the median number of cycles needed until failure; this was 2921 cycles (range, 2586–5450) in the cemented group, 2570 cycles (range, 2500–5107) for the sacroiliac specimens, and 2578 cycles (range, 2540–2623) in the transsacral group (p = 0.153). The cemented group absorbed more energy before failure (8.2 × 105 N*cycles; range, 6.6 × 105–22.6 × 105) compared with the transsacral group (6.5 × 105 N*cycles; range, 6.4 × 105–6.7 × 105) (p = 0.016). There was no difference with the numbers available in terms of fracture site motion (sacroiliac: 2.9 mm, range, 0.7–5.4; cemented: 1.2 mm, range, 0.6–1.9; transsacral: 2.1 mm, range, 1.2–4.8). Probability values for all between-group comparisons were greater than 0.05. The addition of cement to standard sacroiliac screw fixation seemed to change the mode and dynamics of failure in this cadaveric mechanical model. Although no advantages to cement were observed in terms of screw motion or cycles to failure among the different constructs, a cemented, two-screw sacroiliac screw construct resulted in less screw subsidence and greater energy absorbed to failure than an uncemented single transsacral screw. In osteoporotic bone, the addition of cement to sacroiliac screw fixation might improve screw anchorage. However, larger mechanical studies using these findings as pilot data should be performed before applying these preliminary findings clinically.

Assessment of functional outcomes of surgically managed acetabular fractures: a systematic review

Abstract: We performed a systematic review of the literature pertaining to the functional outcomes of the surgical management of acetabular fractures. A total of 69 articles met our inclusion criteria, revealing that eight generic outcome instruments were used, along with five specific instruments. The majority of studies reported outcomes using a version of the d’Aubigne and Postel score, which has not been validated for use in acetabular fracture. Few validated outcome measures were reported. No psychometric testing of outcome instruments was performed. The current assessment of outcomes in surgery for acetabular fractures lacks scientific rigour, and does not give reliable outcome data for either scientific comparison or patient counselling. Take home message: The use of non-validated functional outcome measures is a major limitation of the current literature pertaining to surgical management of acetabular fractures; future studies should use validated outcome measures to ensure the legitimacy of the reported results. Cite this article: Bone Joint J 2016;98-B:690–5.

Outcome after protected full weightbearing treatment in an orthopedic device in diabetic neuropathic arthropathy (Charcot arthropathy): a comparison of unilaterally and bilaterally affected patients

Abstract: Charcot neuropathic arthropathy (CN) is a chronic, progressive, destructive, non-infectious process that most frequently affects the bone architecture of the foot in patients with sensory neuropathy. We evaluated the outcome of protected weightbearing treatment of CN in unilaterally and bilaterally affected patients and secondarily compared outcomes in protected versus unprotected weightbearing treatment. Patient records and radiographs from 2002 to 2012 were retrospectively analyzed. Patients with Type 1 or Type 2 diabetes with peripheral neuropathy were included. Exclusion criteria included immunosuppressive or osteoactive medication and the presence of bone tumors. Ninety patients (101 ft), mean age 60.7 ± 10.6 years at first diagnosis of CN, were identified. Protected weightbearing treatment was achieved by total contact cast or custom-made orthosis. Ulcer, infection, CN recurrence, and amputation rates were recorded. Mean follow-up was 48 (range 1–208) months. Per the Eichenholtz classification, 9 ft were prodromal, 61 in stage 1 (development), 21 in stage 2 (coalescence) and 10 in stage 3 (reconstruction). Duration of protected weightbearing was 20 ± 21 weeks and 22 ± 29 weeks in patients with unilateral and bilateral CN, respectively. In bilaterally affected patients, new ulcers developed in 9/22 (41%) feet. In unilaterally affected patients, new ulcers developed in 5/66 (8%) protected weightbearing feet and 4/13 (31%) unprotected, full weightbearing feet (p = 0.036). The ulceration rate was significantly higher in bilaterally versus unilaterally affected patients with a protected weightbearing regimen (p = 0.004). Soft tissue infection occurred in 1/13 (8%) unprotected weightbearing feet and 1/66 (2%) protected weightbearing feet in unilaterally affected patients, and in 1/22 (4%) protected weightbearing feet of bilaterally affected patients. Recurrence and amputation rates were similar across treatment modalities. Bilateral CN results in significantly more ulcers than unilateral CN and leads to slightly higher soft tissue infections. Protected weightbearing in an orthopedic device can reduce the risk for complications in acute CN of the foot and ankle.

Influence of high-heeled shoes on the sagittal balance of the spine and the whole body.

Abstract: Wearing high heels is associated with chronic pain of the neck, lower back and knees. The mechanisms behind this have not been fully understood. The purpose of this study was to investigate the influence of high-heeled shoes on the sagittal balance of the spine and the whole body in non-habitual wearers of high heels. Lateral standing whole body low-dose radiographs were obtained from 23 female participants (age 29 ± 6 years) with and without high heels and radiological parameters describing the sagittal balance were quantified. These were analyzed for differences between both conditions in the total sample and in subgroups. Standing in high heels was associated with an increased femoral obliquity angle [difference (Δ) 3.0° ± 1.7°, p < 0.0001], and increased knee (Δ 2.4° ± 2.9°, p = 0.0009) and ankle flexion (Δ 38.7° ± 3.4°, p < 0.0001). The differences in C7 and meatus vertical axis, cervical and lumbar lordosis, thoracic kyphosis, spino-sacral angle, pelvic tilt, sacral slope, and spinal tilt were not significant. Individuals adapting with less-than-average knee flexion responded to high heels by an additional increase in cervical lordosis (Δ 5.8° ± 10.7° vs. 1.8° ± 5.3°). In all participants, wearing high heels led to increased flexion of the knees and to more ankle flexion. While some participants responded to high heels primarily through the lower extremities, others used increased cervical lordosis to adapt to the shift of the body’s center of gravity. This could explain the different patterns of pain in the neck, lower back and knees seen in individuals wearing high heels frequently.

Radiographic Measurement of Displacement in Acetabular Fractures: A Systematic Review of the Literature.

Abstract: Objectives:To report methods of measurement of radiographic displacement and radiographic outcomes in acetabular fractures described in the literature.Methods:A systematic review of the English literature was performed using EMBASE and Medline in August 2014. Inclusion criteria were studies

Symphyseal internal rod fixation versus standard plate fixation for open book pelvic ring injuries: a biomechanical study

Abstract: This study investigates the biomechanical stability of a novel technique for symphyseal internal rod fixation (SYMFIX) using a multiaxial spinal screw-rod implant that allows for direct reduction and can be performed percutaneously and compares it to standard internal plate fixation of the symphysis. Standard plate fixation (PLATE, n = 6) and the SYMFIX (n = 6) were tested on pelvic composite models with a simulated open book injury using a universal testing machine. On a previously described testing setup, 500 consecutive cyclic loadings were applied with sinusoidal resulting forces of 200 N. Displacement under loading was measured using an optoelectronic camera system and construct rigidity was calculated as a function of load and displacement. The rigidity of the PLATE construct was 122.8 N/mm (95 % CI: 110.7–134.8), rigidity of the SYMFIX construct 119.3 N/mm (95 % CI: 105.8–132.7). Displacement in the symphyseal area was mean 0.007 mm (95 % CI: 0.003–0.012) in the PLATE group and 0.021 mm (95 % CI: 0.011–0.031) in the SYMFIX group. Displacement in the sacroiliac joint area was mean 0.156 mm (95 % CI: 0.051–0.261) in the PLATE group and 0.120 mm (95 % CI: 0.039–0.201) in the SYMFIX group. In comparison to standard internal plate fixation for the stabilization of open book pelvic ring injuries, symphyseal internal rod fixation using a multiaxial spinal screw-rod implant in vitro shows a similar rigidity and comparable low degrees of displacement.

It is the lateral head tilt, not head rotation, causing an asymmetry of the odontoid-lateral mass interspace.

Abstract: Asymmetry in odontoid-lateral mass interspace in trauma patients is a common finding that regularly leads to additional diagnostic work-up, since its dignity is not entirely clear. There is little evidence in the literature that atlantoaxial asymmetry is associated with C1–C2 instability or (sub) luxation. Asymmetry in odontoid-lateral mass interspace seems to occur occasionally in healthy individuals and patients suffering a cervical spine injury. Congenital abnormalities in odontoid-lateral mass asymmetry may mimic an atlantoaxial asymmetry. The center of C1–C2 rotation is based in the peg of dens axis; therefore, a C1–C2 rotational influence seems unlikely. So far, no study examined the influence of C0–C1–C2 tilt to an asymmetry in odontoid-lateral mass interspace. In order to determine if rotation or tilt influences the lateral atlantodental interval (LADI) and to estimate physiologic values, we examined 300 CT scans of the cervical spine. The mean LADI was 3.57 mm and the mean odontoid-lateral mass asymmetry was 1.0 mm. Head position during CT examination was found to be rotated in 39 % of the cases in more than 5°. Subsequent mean C0/C2 rotation was 4.6°. There was no significant correlation between atlantoaxial asymmetry and head rotation (p = 0.437). The average tilt of C0–C1–C2 was found to be 2°. We found a significant correlation between tilt of C0–C1–C2 and asymmetry in odontoid-lateral mass interspace (p = 0.000). We conclude that an atlantoaxial asymmetry revealed in CT scans of the cervical spine occurs occasionally. Since head tilt correlates with an atlantoaxial asymmetry, it is crucial to perform cervical spine CT scans in a precise straight head position.

A cost-effectiveness analysis of reverse total shoulder arthroplasty versus hemiarthroplasty for the management of complex proximal humeral fractures in the elderly

Abstract: There is ongoing debate regarding the optimal surgical treatment of complex proximal humeral fractures in elderly patients. The aim of this study was to evaluate the cost-effectiveness of reverse total shoulder arthroplasty (RTSA) compared to hemiarthroplasty (HA) in the management of these fractures. A cost–utility analysis using decision tree and Markov modelling based on data from the published literature was conducted. A single-payer perspective with a lifetime time horizon was adopted. A willingness to pay threshold of CAD $50,000 was used. The incremental cost-effectiveness ratio (ICER) was used as the study9s primary outcome measure. In comparison to HA, the incremental cost per QALY gained for RTSA was $13,679. One-way sensitivity analysis revealed the model to be sensitive to the RTSA implant cost and the RTSA procedural costs. Two-way sensitivity analysis suggested RTSA could also be cost-effective within the first two years of surgery with an early complication rate as high as 25% (if RTSA implant cost was approximately $3,000); or conversely, RTSA implant cost could be as high as $8,500 if its early complication rates were 5%. The ICER of $13,679 is well below the WTP threshold of $50,000 and probabilistic sensitivity analysis demonstrated that 92.6% of model simulations favoured RTSA. Our economic analysis found that RTSA for the treatment of complex proximal humeral fractures in the elderly is the preferred economic strategy when compared to HA. The ICER of RTSA is well-below standard willingness to pay thresholds, and its estimate of cost-effectiveness is similar to other highly successful orthopaedic strategies such as total hip arthroplasty for the treatment of hip arthritis.