Muscle: a source of progenitor cells for bone fracture healing

Bone repair failure is a major complication of open fracture, leading to non-union of broken bone extremities and movement at the fracture site. This results in a serious disability for patients. The role played by the periosteum and bone marrow progenitors in bone repair is now well documented. In contrast, limited information is available on the role played by myogenic progenitor cells in bone repair. In a recent article published in BMC Musculoskeletal Disorders, Liu et al. compared the presence of myogenic progenitor (MyoD lineage cells) in closed and open fractures. They showed that myogenic progenitors are present in open, but not closed fractures, suggesting that muscle satellite cells may colonize the fracture site in the absence of intact periosteum. Interestingly, these progenitors sequentially expressed a chondrogenic and, thereafter, an osteoblastic phenotype, suggestive of a functional role in the repair process. This finding opens up new perspectives for the research of orthopedic surgical methods, which could maximize myogenic progenitor access and mobilization to augment bone repair

Improved healing response in delayed unions of the tibia with low-intensity pulsed ultrasound: results of a randomized sham-controlled trial

<p>Abstract</p> <p>Background</p> <p>We compared the healing response of tibial delayed unions between subjects treated with low-intensity pulsed ultrasound (LIPUS) (n = 51) and subjects treated with a sham device (n = 50). Fracture age was ≥ 4 months in all cases. Study personnel and participants were blinded to random treatment assignment throughout the study.</p> <p>Methods</p> <p>This multi-center randomized sham-controlled trial was undertaken at six hospitals in Germany. Adult patients who had sustained a tibial shaft fracture that subsequently showed inadequate progress toward healing (i.e., delayed union) were enrolled and randomized to receive either LIPUS (Exogen 2000/2000+, Smith & Nephew GmbH, Schenefeld, Germany) or an identical nonoperative sham device. The daily treatment duration was 20 minutes, for a period of 16 weeks. Subjects randomly assigned to active treatment had the ultrasound pressure wave signal set at the following parameters: 1.5 MHz frequency, 1 kHz repetition rate, 200 μs pulse duration, 30 mW/cm²spatial intensity. Progress toward healing was estimated from changes in bone mineral density (BMD) and gap area as determined from computed tomography scans. Intention-to-treat analysis was conducted using a multiple imputation methodology.</p> <p>Results</p> <p>Based on log-transformed data, mean improvement in BMD was 1.34 (90% confidence interval (CI) 1.14 to 1.57) times greater for LIPUS-treated subjects compared to sham (p = 0.002). A mean reduction in bone gap area also favored LIPUS treatment (p = 0.014).</p> <p>Conclusions</p> <p>These findings demonstrate significantly greater progress toward bone healing after LIPUS treatment compared to no LIPUS treatment in subjects with established delayed unions of the tibia.</p

Clinical assessment tools identify functional deficits in fragility fracture patients

Tyler D Ames,1 Corinne E Wee,1 Khoi M Le,1 Tiffany L Wang,1 Julie Y Bishop,2 Laura S Phieffer,2 Carmen E Quatman2 1The Ohio State University College of Medicine, 2Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA Purpose: To identify inexpensive, noninvasive, portable, clinical assessment tools that can be used to assess functional performance measures that may put older patients at risk for falls such as balance, handgrip strength, and lumbopelvic control.Patients and methods: Twenty fragility fracture patients and 21 healthy control subjects were evaluated using clinical assessment tools (Nintendo Wii Balance Board [WBB], a handheld dynamometer, and an application for the Apple iPod Touch, the Level Belt) that measure functional performance during activity of daily living tasks. The main outcome measurements were balance (WBB), handgrip strength (handheld dynamometer), and lumbopelvic control (iPod Touch Level Belt), which were compared between fragility fracture patients and healthy controls.Results: Fragility fracture patients had lower scores on the vertical component of the WBB Torso Twist task (P=0.042) and greater medial&ndash;lateral lumbopelvic sway during a 40 m walk (P=0.026) when compared to healthy controls. Unexpectedly, the fracture patients had significantly higher scores on the left leg (P=0.020) and total components (P=0.010) of the WBB Single Leg Stand task as well as less faults during the left Single Leg Stand task (P=0.003).Conclusion: The clinical assessment tools utilized in this study are relatively inexpensive and portable tools of performance measures capable of detecting differences in postural sway between fragility fracture patients and controls. Keywords: fall risk, geriatric fracture, Nintendo Wii Balance Board, Level Belt, fragility fractur

The Synergistic Effect of Autograft and BMP-7 in the Treatment of Atrophic Nonunions

Combining autologous bone graft and recombinant human bone morphogenetic protein-7 (BMP-7) to treat long-bone fracture aseptic atrophic nonunions theoretically could promote bone healing at higher rates than each of these grafting agents separately. We retrospectively reviewed prospectively collected data on patient general characteristics, clinical outcomes, and complications over 3 years to determine the healing rates and the incidence of complications and adverse events of this “graft expansion rationale.” There were 45 patients (32 male) with a median age of 43 years (range, 19–76 years). Minimum followup was 12 months (mean, 24.5 months; range, 12–65 months). There were seven humeral, 19 femoral, and 19 tibial nonunions. The median number of prior operations was two (range, 1–7). All fractures united. Clinical and radiographic union occurred within a median of 5 months (range, 3–14 months) and 6 months (range, 4–16 months), respectively. Thirty-nine (87%) patients returned to their preinjury occupation at a mean of 4.2 months (range, 3–6 months). The median visual analog scale pain score was 0.9 (range, 0–2.8; maximum 10), and the median functional score was 86 (range, 67–95; maximum 100) at the final followup. BMP-7 as a bone-stimulating agent combined with conventional autograft resulted in a nonunion healing rate of 100% in these 45 patients