Exposure of zebra mussels to radial extracorporeal shock waves: implications for treatment of fracture nonunions

Background Radial extracorporeal shock wave therapy (rESWT) is an attractive, non-invasive therapy option to manage fracture nonunions of superficial bones, with a reported success rate of approximately 75%. Using zebra mussels (Dreissena polymorpha), we recently demonstrated that induction of biomineralization after exposure to focused extracorporeal shock waves (fESWs) is not restricted to the region of direct energy transfer into calcified tissue. This study tested the hypothesis that radial extracorporeal shock waves (rESWs) also induce biomineralization in regions not directly exposed to the shock wave energy in zebra mussels. Methods Zebra mussels were exposed on the left valve to 1000 rESWs at different air pressure (between 0 and 4 bar), followed by incubation in calcein solution for 24 h. Biomineralization was evaluated by investigating the fluorescence signal intensity found on sections of the left and right valves prepared two weeks after exposure. Results General linear model analysis demonstrated statistically significant (p < 0.05) effects of the applied shock wave energy as well as of the side (left/exposed vs. right/unexposed) and the investigated region of the valve (at the position of exposure vs. positions at a distance to the exposure) on the mean fluorescence signal intensity values, as well as statistically significant combined energy × region and energy × side × region effects. The highest mean fluorescence signal intensity value was found next to the umbo, i.e., not at the position of direct exposure to rESWs. Conclusions As in the application of fESWs, induction of biomineralization by exposure to rESWs may not be restricted to the region of direct energy transfer into calcified tissue. Furthermore, the results of this study may contribute to better understand why the application of higher energy flux densities beyond a certain threshold does not necessarily lead to higher success rates when treating fracture nonunions with extracorporeal shock wave therapy.

Exposure of Zebra Mussels to Radial Extracorporeal Shock Waves: Implications for Treatment of Fracture Nonunions

Background Radial extracorporeal shock wave therapy (rESWT) is an attractive, non-invasive therapy option to manage fracture nonunions of superficial bones, with a reported success rate of approximately 75%. Using zebra mussels (Dreissena polymorpha), we recently demonstrated that induction of biomineralization after exposure to focused extracorporeal shock waves (fESWs) is not restricted to the region of direct energy transfer into calcified tissue. This study tested the hypothesis that radial extracorporeal shock waves (rESWs) also induce biomineralization in regions not directly exposed to the shock wave energy in zebra mussels. Methods Zebra mussels were exposed on the left valve to 1000 rESWs at different air pressure (between 0 and 4 bar), followed by incubation in calcein solution for 24 hours. Biomineralization was evaluated by investigating the fluorescence signal intensity found on sections of the left and right valves prepared two weeks after exposure. Results General linear model analysis demonstrated statistically significant (p &lt; 0.05) effects of the applied shock wave energy as well as of the side (left/exposed vs. right/unexposed) and the investigated region of the valve (at the position of exposure vs. positions at a distance to the exposure) on the mean fluorescence signal intensity values, as well as statistically significant combined energy &times; region and energy &times; side &times; region effects. The highest mean fluorescence signal intensity value was found next to the umbo, i.e., not at the position of direct exposure to rESWs. Conclusions As in the application of fESWs, induction of biomineralization by exposure to rESWs may not be restricted to the region of direct energy transfer into calcified tissue. Furthermore, the results of this study may contribute to better understand why the application of higher energy flux densities beyond a certain threshold does not necessarily lead to higher success rates when treating fracture nonunions with extracorporeal shock wave therapy.

Distal Femoral Replacement for Fractures Allows for Early Mobilization with Low Complication Rates: A Multicenter Review

Periprosthetic fractures around a total knee arthroplasty (TKA), comminuted and intra-articular femur fractures, or fracture nonunions in osteoporotic bone represent technically challenging problems. This is particularly true when the fracture involves a loose femoral component or the pattern results in suboptimal fixation potential. These clinical indications often arise in an older and comorbid patient population in whom a principal goal of treatment includes allowing for early mobilization. Limited data indicate that arthroplasty via distal femoral replacement (DFR) is a reasonable alternative to open reduction and internal fixation, allowing for early ambulation with low complication rates. We performed a retrospective review of trauma and arthroplasty surgeries at three tertiary referral institutions. Adult patients treated for the above with a DFR were included. Patients with active infection, open and/or high-energy injuries and revisions unrelated to fracture were excluded. Patient demographics, treatment details, and outcomes were assessed. Between 2002 and 2017, 90 DFR's were performed for the above indications with a mean follow-up of 24 months. Postoperatively, 80 patients (88%) were allowed to weight bear as tolerated, and at final follow-up, 9 patients (10%) remained dependent on a wheelchair. The average arc of motion at final follow-up was 95 degrees. There were seven (8%) implant-related complications requiring secondary surgeries: two infections, one with associated component loosening; one fracture of the hinge mechanism and one femoral component failure in conjunction with a patellofemoral dislocation (both requiring revision); one case of patellofemoral arthrosis in a patient with an unresurfaced patella; one periprosthetic fracture with associated wound dehiscence; and one case of arthrofibrosis. In each of these cases, only modular components of the DFR were exchanged. All nonmodular components cemented into the femur or tibia were retained. DFR provides a viable reconstruction option in the treatment of acute distal femur fractures, periprosthetic femur fractures, and fracture nonunions. We noted that in an elderly patient population with high comorbidities, the complication and secondary surgery rates remained relatively low, while allowing for immediate weight bearing.

Hand Surgeons Are Tackling Tougher Scaphoids: A Study of ABOS Candidate Data

Background This study will evaluate whether those who have completed a hand fellowship treat a disproportionate number of scaphoid fractures based on recent American Board of Orthopaedic Surgery (ABOS) data. We hypothesize that surgeons who have completed a fellowship in hand surgery will address most surgically treated scaphoid fractures, particularly those with fracture nonunions or requiring graft. Methods We queried the ABOS database for case log information submitted for part II of the ABOS examination. This search included all cases with Current Procedural Terminology codes for procedures related to scaphoid fixation. Demographic information, case volume, type of case, and complication rate were compared for hand fellowship–trained surgeons and those who had completed other fellowships as well as non-fellowship-trained surgeons. Results During the study period, 1686 surgeons reported treating 4244 scaphoid fractures. Of these surgeons, 1180 had completed a hand surgery fellowship. Hand fellowship–trained surgeons were shown to have operatively treated more scaphoid fractures both in total volume and on a per-surgeon basis. Hand fellowship–trained surgeons were also found to have performed a significantly higher proportion of difficult cases, which were those listed as being a malunion/nonunion or those incorporating a pedicle graft. There was no difference in the complication rate between the 2 groups. Conclusion Among those orthopedic surgeons reporting case information for part II of the ABOS certification examination, statistically significant differences exist in case volume and case difficulty among surgeons with different areas of fellowship training. Complication rates increase with patient age and examination year.

Low-Intensity Pulsed Ultrasound Therapy: A Nonsurgical Treatment Modality for Mandible Fracture Nonunion?

Standard treatment of mandibular nonunion includes debridement and application of maxillomandibular or rigid internal fixation techniques, with adjunctive bone grafting when necessary. Frequently described in the orthopaedic literature, low-intensity pulsed ultrasound therapy (LIPUS) is a noninvasive treatment modality used to accelerate healing of fresh fractures and established nonunions. The purpose of this study was to conduct a systematic review to determine the extent of LIPUS study in the treatment of mandibular nonunions to identify whether LIPUS represents an effective nonsurgical alternative or adjunct for nonunion management. A literature review was conducted to investigate published reports on the utilization of LIPUS in treating mandible fracture nonunions. The search yielded two randomized controlled trials demonstrating favorable healing parameters in fresh human mandible fractures treated with LIPUS, two randomized controlled trials demonstrating osteogenic differentiation in human mandibular fracture cellular components, and one study reporting improved healing at rabbit mandibular osteotomy sites. No articles published reports studying LIPUS in facial fracture nonunion were identified. This report reviews published literature on mandibular nonunions, and the evidence of LIPUS use in long bone nonunions. There are no known studies presenting LIPUS treatment of mandible fracture nonunions. However, on the basis of published orthopaedic data, LIPUS therapy could be considered as an adjunct or alternative to traditional surgical management of select mandible fracture nonunions.

Antibiofilm efficacy of focused high-energy extracorporeal shockwaves and antibiotics in vitro

Aims Biofilm formation is one of the primary reasons for the difficulty in treating implant-related infections (IRIs). Focused high-energy extracorporeal shockwave therapy (fhESWT), which is a treatment modality for fracture nonunions, has been shown to have a direct antibacterial effect on planktonic bacteria. The goal of the present study was to investigate the effect of fhESWT on Staphylococcus aureus biofilms in vitro in the presence and absence of antibiotic agents. Methods S. aureus biofilms were grown on titanium discs (13 mm × 4 mm) in a bioreactor for 48 hours. Shockwaves were applied with either 250, 500, or 1,000 impulses onto the discs surrounded by either phosphate-buffered saline or antibiotic (rifampin alone or in combination with nafcillin). The number of viable bacteria was determined by quantitative culture after sonication. Representative samples were taken for scanning electron microscopy. Results The application of fhESWT led to a ten-fold reduction in bacterial counts on the metal discs for all impulse numbers compared to the control (p < 0.001). Increasing the number of impulses did not further reduce bacterial counts in the absence of antibiotics (all p > 0.289). Antibiotics alone reduced the number of bacteria on the discs; however, the combined application of the fhESWT and antibiotic administration further reduced the bacterial count compared to the antibiotic treatment only (p = 0.032). Conclusion The use of fhESWT significantly reduced the colony-forming unit (CFU) count of a S. aureus biofilm in our model independently, and in combination with antibiotics. Therefore, the supplementary application of fhESWT could be a helpful tool in the treatment of IFIs in certain cases, including infected nonunions. Cite this article: Bone Joint Res 2021;10(1):77–84.