Background:Radial head arthroplasty (RHA) implants are designed either to promote osseo-integration with an anatomic stem or function as a loose-fitting spacer. Anatomic implants have shown painful loosening leading to revision or removal, making the loose-fitting design an appealing alternative. This study evaluates short-term survivorship and clinical, radiographic, and patient reported outcomes following RHA using the DePuy Synthes monoblock loose fit radial head replacement system. Methods:Nineteen patients (mean age 54 SD 17 years), who underwent RHA were enrolled, with a mean follow-up of 14.9 SD 6.8 months. Fractures were classified using Mason and Regan-Morrey systems. Fifteen patients returned for in-person evaluation with x-rays, physician and physical therapist examination and patient reported outcome (PRO) questionnaires. Four remote participants completed PROs only. Results:The cohort consisted of 8 females and 11 males, with 10 patients sustaining associated elbow dislocations and 13 with concurrent coronoid fractures. No patient had the implant removed or revised. PROs indicated excellent functional outcomes: Mayo Elbow Performance Score of 90 SD 12, QuickDash of 13 SD 9 (minor disability) and EQ-5D of 0.77 SD 0.18 (mild disability). Grip strength in the operative limb was 90% SD 14% of the non-operative and range of motion was greater than 90% of the non-operative side. Heterotopic bone formation was noted in 7 patients but did not limit motion. Mild periprosthetic radiolucency around the stem was noted in 14 patients. Moderate capitellar erosion was noted in one patient with an Essex-Lopresti injury. Conclusion:The DePuy Synthes radial head replacement system demonstrated excellent shortterm outcomes in terms of survivorship, functional recovery and patient satisfaction. Although mild radiographic lucencies and heterotopic ossification were observed, they did not impact functional outcome. These findings support the safety and efficacy of this implant, though longer-term follow-up is necessary to assess its durability and performance. Level of Evidence:IV.

Background:The purpose of this study was to examine the proportion of patients who returned for their previously scheduled knee arthroscopy procedure following state-mandated cancellation of elective procedures during COVID-19 lockdown. Methods:We reviewed a retrospective cohort of patients who had planned knee arthroscopies, excluding ligament reconstruction and irrigation/ debridement, cancelled for a date between March and June 2020. The cohort was evaluated for scheduling outcome, returned versus did not return for surgery, before March 2022. Cancellation and reschedule dates, reason for not returning for surgery, patient demographics, and planned surgical characteristics were collected. Characteristics between patients who returned versus did not return were compared using statistical tests of independence. Results:The cohort consisted of 66 patients; 53 (80%) rescheduled and 13 (20%) did not return. For those who rescheduled, the average time between cancellation and surgery was 115 days (sd=16 days). There were various reasons for not rescheduling surgery: eight (62%) had symptom alleviation; two (15%) had logistical barriers; three (23%) were lost to follow-up. Obesity status had a trend towards significance with lower proportion of rescheduled procedures for non-obese patients (68%) compared to obese patients (89%, p=0.057). Conclusion:Our study highlights a natural experiment in forced delay of elective knee arthroscopies, which may be a surrogate for conservative management. The proportion of patients who did not return for a scheduled knee arthroscopy surgery (20%) is higher than what has been reported previously (11%) and 62% of these patients found symptom relief. However, 80% of the cohort did return for knee arthroscopy in within two years, suggesting delaying surgery will not alleviate symptoms for the majority of patients. Level of Evidence: IV.

INTRODUCTION:Food insecurity is the condition of limited access to healthy and safe food. Malnutrition resulting from food insecurity is a concern particularly in the surgical population due to the association with impaired healing. This aim of this study was to report the incidence and risk factors for food insecurity in the orthopaedic trauma population. METHODS:Orthopaedic trauma centers at three distinct regions of the United States enrolled patients who had undergone extremity or pelvis fracture fixation within the previous 6 months. Participants completed the United States Department of Agriculture Household Food Insecurity Survey, and food insecurity was defined as a score ≥3. In addition, participants recorded patient demographics and injury/treatment/household characteristics and completed information about diet quality. Diet quality was compared between households with and without food insecurity using chi-square or Fisher exact tests. Logistic regression was used to create a multivariable model of factors associated with greater odds of food insecurity. RESULTS:Food insecurity was documented in 11.5% (81/703) of households. Households with food insecurity were less likely to report daily consumption of fruit, vegetables, and protein-rich foods. We found a greater odds of food insecurity among households with a yearly income of <$50,000 (odds ratio = 4.30 [95% confidence interval = 2.07 to 8.92], P < 0.001), tobacco use (2.33 [1.26 to 4.28], P = 0.007), Medicaid or no insurance (2.34 [1.19 to 4.62], P = 0.014), and Hispanic or Latino ethnicity (4.55 [1.69 to 12.24], P = 0.003), for each 10-year decrease in age (1.19 [1.00 to 1.40], P = 0.045), multiple surgically treated fractures (2.41 [1.08 to 5.35], P = 0.031), and for each additional 15 minutes of travel time to the nearest grocery store (2.12 [1.37 to 3.26], P < 0.001). CONCLUSION:Food insecurity is common in the orthopaedic trauma population, and households with food insecurity are more likely to have low diet quality. Nutrition supplementation during the healing phase after trauma and referral to nutrition assistance programs has the potential to mitigate malnutrition and prevent negative outcomes resulting from food insecurity.

The purpose was to directly assess in-competition thermoregulatory responses in recreational runners during a city marathon conducted in cool, ambient conditions using a two-pill ingestion strategy.

Nonsteroidal anti-inflammatory drug use is prevalent in sport however the risk associated with their use in athletes is not well-understood. This review discusses the pharmacology of nonsteroidal anti-inflammatory drugs and the prevalence of their use in different sports and factors driving this. Use is very high in sports such as professional football and is sometimes by routine without indication and without medical supervision. However there is a paucity of evidence in other sports. There is good evidence for use of nonsteroidal anti-inflammatory drugs following an acute injury but they may prevent normal tissue healing and remodelling if used longer term for musculoskeletal injuries. There are well-known risks of cardiac, gastrointestinal and renal side effects but little specific data for athletes. Renal events are discussed in detail including the cumulative effect that nonsteroidal anti-inflammatory drug use, dehydration and concurrent illness can have to produce significant renal and systemic insult. We then discuss a pragmatic prescribing model enabling clinicians to utilise the beneficial effects of these medications whilst minimising risks.

The controlled dynamization of fractures can promote natural fracture healing by callus formation, while overly rigid fixation can suppress healing. The advent of locked plating technology enabled new strategies for the controlled dynamization of fractures, such as far cortical locking (FCL) screws or active plates with elastically suspended screw holes. However, these strategies did not allow for the use of non-locking screws, which are typically used to reduce bone fragments to the plate. This study documents the first in vivo study on the healing of ovine tibia osteotomies stabilized with an advanced active plate (AAP). This AAP allowed plate application using any combination of locking and non-locking screws to support a wide range of plate application techniques. At week 9 post-surgery, tibiae were harvested and tested in torsion to failure to assess the healing strength. The five tibiae stabilized with an AAP regained 54% of their native strength and failed by spiral fracture through a screw hole, which did not involve the healed osteotomy. In comparison, tibiae stabilized with a standard locking plate recovered 17% of their strength and sustained failure through the osteotomy. These results further support the stimulatory effect of controlled motion on fracture healing. As such, the controlled dynamization of locked plating constructs may hold the potential to reduce healing complications and may shorten the time to return to function. Integrating controlled dynamization into fracture plates that support a standard fixation technique may facilitate the clinical adoption of dynamic plating.

Background: Femoral fragility fractures in older adults can result in devastating loss of physical function and independence. Skeletal muscle atrophy likely contributes to disability. The purpose of this study was to characterize the change in skeletal muscle mass, investigate the relationship with malnutrition and physical function, and identify risk factors for skeletal muscle loss. Methods: Adults ≥65 years of age who were treated with operative fixation of an isolated femoral fragility fracture were enrolled in this multicenter, prospective observational study. Skeletal muscle mass was assessed within 72 hours of admission using multifrequency bioelectrical impedance analysis, which was repeated at 6 weeks, 3 months, and 6 months. Sarcopenia was defined by sex-specific cutoffs for the appendicular skeletal muscle mass index. The Mini Nutritional Assessment was used to measure nutritional status at the time of injury. Physical function was measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function domain. Linear mixed models were used to evaluate changes in skeletal muscle mass and PROMIS Physical Function scores over time and to evaluate factors associated with skeletal muscle mass changes. Results: Ninety participants (74% female) with a mean age of 77.6 ± 9.0 years were enrolled. At the time of injury, 30 (33%) were sarcopenic and 44 (49%) were at risk for malnutrition or had malnutrition. Older age was associated with lower skeletal muscle mass (age of ≥75 versus <75 years: least squares mean [and standard error], −3.3 ± 1.6 kg; p = 0.042). From the time of injury to 6 weeks, participants lost an average of 2.4 kg (9%) of skeletal muscle mass (95% confidence interval [CI] = ‒3.0 to ‒1.8 kg; p < 0.001). This early loss did not recover by 6 months (1.8 kg persistent loss compared with baseline [95% CI = ‒2.5 to ‒1.1 kg]; p < 0.001). Participants with normal nutritional status lost more skeletal muscle mass from baseline to 6 weeks after injury compared with those with malnutrition (1.3 kg more loss [standard error, 0.6 kg]; p = 0.036). A 1-kg decrease in skeletal muscle mass was associated with an 8-point decrease in the PROMIS Physical Function (model parameter estimate, 0.12 [standard error, 0.04]; p = 0.002). Conclusions: We found that older adults with femoral fragility fractures lost substantial skeletal muscle mass and physical function. Participants with adequate baseline nutrition actually lost more muscle mass than those who were malnourished, indicating that future investigations of interventions to prevent muscle loss should focus on older adults regardless of nutritional status. Level of Evidence: Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Objectives To review outcomes of a consecutive, non-selected series of distal femur fractures treated with a dynamic plate construct and allowed unrestricted weight bearing immediately after surgery. Design Retrospective consecutive case series. Setting Level 2 trauma center Patients/Participants Thirty-one consecutive distal femur fractures in 29 patients with 33A and 33C fractures stabilized with a distal femur locking plate and Far Cortical Locking diaphyseal screws. Intervention All patients were allowed immediate unrestricted weight bearing with assistive devices post-surgery. Main Outcome Measure Loss of reduction from immediate post-operative alignment, implant failure, nonunion, and medical complications. Results No loss of alignment greater than three degrees in the lateral distal femoral angle was noted at healing. Two implant failures occurred, one in the first five weeks and another in an established nonunion. Mortality at one year was 6.5%. Readmission for medical complications was noted in 6.5% of patients. Conclusions Immediate, unrestricted weight bearing after fixation of 33A and 33C distal femur fractures with a dynamic plate construct may be safe, with a low risk of implant failure or loss of coronal plane alignment. Relative to historical reports, morbidity and mortality in our cohort were improved with early weight-bearing. Level of Evidence Therapeutic Level IV, case series

Preoperative planning of comminuted fracture repair using 3D printed anatomical models is enabling surgeons to visualize and simulate the fracture reduction processes before surgery. However, the preparation of such models can be challenging due to the complexity of certain fractures, particularly in preserving fine detail in bone fragments, maintaining the positioning of displaced fragments, and accurate positioning of multiple bones. This study described several key technical considerations for preparing 3D printed anatomical models for comminuted fracture preoperative planning. An optimized segmentation protocol was developed that preserves fine detail in bone fragments, resulting in a more accurate representation of the fracture. Additionally, struts were manually added to the digital model to maintain the positioning of displaced fragments after fabrication, reducing the likelihood of errors during printing or misrepresentation of fragment positioning. Magnets were also used to enable separation and visualization of accurate positioning of multiple bones, making it easier to visualize fracture components otherwise obscured by the anatomy. Finally, the infill for non-target structures was adjusted to minimize print time and material wastage. These technical optimizations improved the accuracy and efficiency of preparing 3D printed anatomical models for comminuted fracture preoperative planning, improving opportunities for surgeons to better plan surgical treatment in advance, reducing the likelihood of errors, with the goal of improving surgical outcomes.

Femoral fragility fractures in the elderly result in devastating loss of physical function and muscle mass, which is a direct result of immobilization and nutrient deficiencies during healing. A better understanding of how muscle mass responds to injury is needed to critically evaluate nutrition interventions designed to prevent muscle loss and optimize function. The purpose of this study was to document sarcopenia, nutrition status, and changes in muscle mass after femoral fragility fractures. A two-center prospective observational study enrolled individuals ≥65 years old admitted for operative fixation of a low-energy femoral fracture. Body composition was assessed within 72 hours of admission using bioelectrical impedance and repeated 6 and 12 weeks after injury. Sarcopenia was defined by gender-specific cutoffs for appendicular skeletal muscle mass index. Malnutrition was defined by Mini Nutritional Assessment®. Wilcoxon Signed Rank test was used to assess 6 and 12-week change from baseline in skeletal muscle mass (SMM). Wilcoxon Rank Sum test was used to compare the change in SMM in those with vs without malnutrition and sarcopenia. SMM results are presented as median (interquartile range). Thirty participants (27% male) age 76.9 ± 8.9 years were enrolled. At baseline, 11 (37%) were sarcopenic, and 17 (59%) were at risk of malnutrition. SMM decreased 1.75kg (−3.30 to −0.40, p < 0.001) by 6 weeks post-injury. By 12 weeks, participants lost 3.04 kg of SMM (−4.49 to −1.45), p < 0.001). Participants with adequate baseline nutrition status lost more SMM at 6 weeks compared to those with at risk of malnutrition (−3.56 kg (−4.65 to −1.60) versus −1.22 kg (−2.00 to −0.20), P = 0.01). No difference was observed in SMM loss between those with vs without sarcopenia at baseline. Femoral fragility fractures result in devastating losses of skeletal muscle mass. Most were at risk of malnutrition, but participants with adequate baseline nutrition lost more muscle mass, indicating that future investigations of interventions to prevent muscle loss should focus on all fragility fracture patients regardless of nutrition status. These results highlight the need for further investigation into interventions to mitigate muscle loss after injury. Orthopedic Trauma Association.

Total elbow arthroplasty (TEA) is a treatment option for patients with rheumatoid arthritis, post-traumatic arthritis, or distal humerus fracture. The objective of this study was to evaluate the clinical, functional, and radiographic outcomes of the semiconstrained Nexel Total Elbow (Nexel) at a single center. This is a retrospective case series of consecutive Nexel TEA procedures at a single center between 2014 and 2019. Of the 21 TEAs, 18 were alive and asked to return to the clinic to complete a physical exam, radiographs, the Mayo Elbow Performance Score, Quick Disabilities of the Arm, Shoulder, and Hand, and EuroQol 5D. Patients who could not return in person were offered a remote participation option. Outcomes included the following: implant survival, surgical complications, reoperation for any reason, radiographic assessment to identify loosening and bushing wear, and mean scores on patient-reported outcomes. There were 11 TEA procedures who responded (61%), with eight returning to the clinic and three remote participants. The mean follow-up was 53.3 months (28-89 months). None of the TEAs were revised or reoperated on for any reason; the survival rate was 100%. One TEA (13%) had radiographic evidence of loosening, limited to the humeral component. There was no evidence of bushing wear. One TEA experienced ulnar nerve neuropraxia postoperatively, without permanent dysfunction (13%). The majority of patients reported satisfactory outcomes as measured by the Mayo Elbow Performance Score (73%), with a mean score of 90 (standard deviation [sd] = 13). On average, patients reported minimal disability on the Quick Disabilities of the Arm, Shoulder, and Hand (mean = 29, sd = 23) and relatively high health-related quality of life (EuroQol 5D, mean = 0.83, sd = 0.08). Clinical and radiographic results of the Nexel TEA, a semiconstrained implant, were favorable. In contrast to the high complication rate and concerning radiographic findings reported previously, the current study reports 100% implant survival, with revision or indication for revision as the endpoint, and low rates of complications with an average of 53 months of follow-up. Bushing wear was not identified as a problem in this series; however, loosening of the humeral component may emerge as an indication for revision. More studies on the Nexel TEA are needed to better understand clinical and radiographic outcomes.

Malnutrition increases the risk for adverse outcomes after musculoskeletal trauma. Food insecurity is an increasingly recognized risk factor for malnutrition. The purpose of this investigation is to evaluate the prevalence and risk factors for food insecurity in a diverse population treated for operative fracture fixation. A two-center study (Midwest and Pacific Northwest) enrolled participants of any age within 6 months of operative fixation of pelvis or extremity fractures. Food insecurity was assessed using the USDA Household Food Insecurity questionnaire. A score ≥3 indicated food insecurity, 1 or 2 indicated marginal food security, and 0 indicated high food security. Subgroup analysis was performed for participants with available demographic, income, and food access data. Differences between food insecure and food secure participants in continuous and categorical variables were evaluated using the Wilcoxon sum rank test and Fisher's exact test, respectively. Spearman's correlation was used to describe associations between food security scores and participant characteristics. Logistic regression was used to relate patient demographics and odds of food insecurity. Of the 476 participants enrolled, 53 (11%) were food insecure, 48 (10%) had marginal food security, and 375 (79%) were food secure. Those with food insecurity were more commonly female (p < 0.0001). Participants with a household income ≤$15,000 were 5.7 times more likely to be food insecure (95% CI 1.8–18.1). Widowed/single/divorced participants were 10.2 times more likely to experience food insecurity than married/partnered participants (95% CI 2.3–45.6). Median time to the nearest full-service grocery store was significantly longer for food insecure (t = 10 minutes) than for food secure participants (t = 7 minutes, p = 0.0202). Time to store demonstrated a weak correlation with food security score (r = 0.23, p = 0.0041). Age (r = −0.08, p = 0.327) and hours working (r = −0.10, p = 0.429) demonstrated no correlation with food security score. Food insecurity is common in the musculoskeletal trauma population. Those with lower household incomes and living alone are more likely to experience food insecurity. Food insecurity is a potentially modifiable risk factor for malnutrition-related complications after operative fracture fixation. None.

Paralympic Blind Association Football has the highest rate of injury of any Paralympic sport and head injuries are common. This study aims to quantify head impact incidence and magnitude in Blind Football, and to examine contributing factors. This Observational study based on a Blind Football Team comprising seven male athletes 28.63 years (SD 9.74, range 16-46) over 6 months. Head mounted impact sensors were used to measure the frequency and location of impacts, as well as their linear acceleration and rotational velocity. Cervical isometric strength and proprioception was measured. There were 374 impacts recorded in 212.5 athlete hours. There was a higher rate of impacts in matches than training (Incidence Risk Ratio 2.58, 95% CI 2.01-3.30). Greater cervical strength was associated with reduced linear acceleration of impacts (R2 = 0.1912, p = .020). Blind Football players are exposed to a greater number of head impacts in matches than training. Neck muscle strength may influence magnitude of head impact forces in this sport but further study is required to further investigate.

Background Blind Football has the highest rate of injury of any Paralympic sport. Head injuries, including concussion, represent a large proportion of these injuries. Blind athletes are less able to anticipate impacts. It has been shown in other sports that athletes with greater neck strength are better able to resist head impacts in a laboratory, and that they are less likely to sustain a concussion. Objective To establish whether isometric neck strength influenced head impact forces in Blind Football. Design Observational study. Setting International Blind Football training and matches over six-months. Patients (or Participants) England Blind Football squad (7 males, mean age 28.6y) Interventions (or assessment of risk factors) Isometric neck strength was measured once during preseason using a hand-held dynamometer. Head impact data was recorded using a head mounted accelerometer and gyroscope (GForce Tracker) attached to player’s mandatory blindfolds. Main outcome measurements Head impact location (front, back, left or right) was recorded. Linear regression was performed to compare mean linear acceleration and rotational velocity to isometric cervical strength (flexion, extension, left lateral flexion and right lateral flexion) with movements paired to the impact direction they oppose. Results A total of 212.5 player hours were recorded (192.5 hours in training and 20 hours in matches). Increased cervical strength was associated with reduced mean linear acceleration (R2=0.1912, p=0.020) when comparing opposing movement to respective impact location. There was no association between cervical strength and rotational velocity (R2=0.001, p=0.861) or between number of impacts (R2=0.4354 p=0.1068). Conclusions Elite Blind Football players with greater cervical strength were subject to head impacts with smaller linear acceleration. This is consistent with existing research in able-bodied athletes and provides an additional factor of the live game play setting in Blind Football. Further research is required to determine if cervical strength training can reduce the risk of concussion in Blind Footballers.

We describe a previously unknown mechanism of injury for isolated lateral collateral ligament strain as well as a novel clinical sign. The mechanism of injury is poorly understood and testing of the LCL is challenging and so we aim to add to the evidence base in this area. We present two cases in professional football where LCL injury occurred after passing the ball laterally using forced external rotation of their feet with the knee in extension. Varus stress test was negative in both cases, but the pain was reproduced in long-legged sitting with the left leg crossed over the right at the ankle. This is a novel mechanism of injury with potential for a new clinic sign. Increased awareness of this mechanism of injury may allow clinicians to identify other cases in the future. Furthermore, with additional investigation, this provocative position could give rise to a new clinical sign.

BACKGROUND:Decreasing the stiffness of locked plating constructs can promote natural fracture healing by controlled dynamization of the fracture. This biomechanical study compared the effect of 4 different stiffness reduction methods on interfragmentary motion by measuring axial motion and shear motion at the fracture site.METHODS:Distal femur locking plates were applied to bridge a metadiaphyseal fracture in femur surrogates. A locked construct with a short-bridge span served as the nondynamized control group (LOCKED). Four different methods for stiffness reduction were evaluated: replacing diaphyseal locking screws with nonlocked screws (NONLOCKED); bridge dynamization (BRIDGE) with 2 empty screw holes proximal to the fracture; screw dynamization with far cortical locking (FCL) screws; and plate dynamization with active locking plates (ACTIVE). Construct stiffness, axial motion, and shear motion at the fracture site were measured to characterize each dynamization methods.RESULTS:Compared with LOCKED control constructs, NONLOCKED constructs had a similar stiffness (P = 0.08), axial motion (P = 0.07), and shear motion (P = 0.97). BRIDGE constructs reduced stiffness by 45% compared with LOCKED constructs (P < 0.001), but interfragmentary motion was dominated by shear. Compared with LOCKED constructs, FCL and ACTIVE constructs reduced stiffness by 62% (P < 0.001) and 75% (P < 0.001), respectively, and significantly increased axial motion, but not shear motion.CONCLUSIONS:In a surrogate model of a distal femur fracture, replacing locked with nonlocked diaphyseal screws does not significantly decrease construct stiffness and does not enhance interfragmentary motion. A longer bridge span primarily increases shear motion, not axial motion. The use of FCL screws or active plating delivers axial dynamization without introducing shear motion.

BACKGROUNDRigid locked plating constructs can suppress fracture healing by inhibiting interfragmentary motion required to stimulate natural bone healing by callus formation. Dynamic fixation with active locking plates reduces construct stiffness, enables controlled interfragmentary motion, and has been shown to induce faster and stronger bone healing in vivo compared to rigid locking plates. This prospective observational study represents the first clinical use of active locking plates. It documents our early clinical experience with active plates for stabilization of humeral shaft fractures to assess their durability and understand potential complications.METHODSEleven consecutive patients with humeral shaft fractures (AO/OTA types 12 A-C) were prospectively enrolled at a level I and a level II trauma center. Fractures were stabilized by using active locking plates without supplemental bone graft or bone morphogenic proteins. The screw holes of active locking plates are elastically suspended in elastomer envelopes inside the plate, enabling up to 1.5 mm of controlled interfragmentary motion. Progression of fracture healing and integrity of implant fixation was assessed radiographically at 3, 6, 12, and 24 weeks post surgery. Patient-reported functional outcome measures were obtained at 6, 12, and 24 weeks post surgery. The primary endpoint of this study was plate durability in absence of plate bending or breakage, or failure of the elastically suspended locking hole mechanism. Secondary endpoints included fracture healing, complications requiring revision surgery, and functional outcome scores.RESULTSThe eleven patients had six simple AO/ OTA type 12A fractures, three wedge type 12B fractures, and two comminuted type 12C fracture, including one open fracture. All active locking plates endured the 6-month loading period without any signs of fatigue or failure. Ten of eleven fractures healed at 10.9 ± 5.2 weeks, as evident by bridging callus and pain-free function. One fracture required revision surgery 37 weeks post surgery due to late fixation failure at the screwbone interface in the presence of a atrophic delayed union. The average Disability of the Arm, Shoulder and Hand (DASH) score improved from 31 ± 22 at week 6 to 13 ± 15 by week 24, approaching that of the normal, healthy population (DASH = 10.1). By week 12, the difference between Constant shoulder scores, expressed as the difference between the affected and contralateral arm (8 ± 8), was considered excellent. By week 24, the SF-12 physical health score (44 ± 9) and mental health score (48 ± 11) approached the mean value of 50 that represents the norm for the general U.S. population.CONCLUSIONAbsence of failure of the plate and locking holes suggests that dynamic fixation of humeral shaft fractures with active plates provides safe and effective fixation. Moreover, early callus bridging and excellent functional outcome scores suggest that dynamic fixation with active locking plates may promote increased fracture healing over standard locked plating.

OBJECTIVES:Active plates dynamize a fracture by elastic suspension of screw holes within the plate. We hypothesized that dynamic stabilization with active plates delivers stronger healing relative to standard compression plating. METHODS:Twelve sheep were randomized to receive either a standard compression plate (CP) or an active plate (ACTIVE) for stabilization of an anatomically reduced tibial osteotomy. In the CP group, absolute stabilization was pursued by interfragmentary compression with 6 cortical screws. In the ACTIVE group, dynamic stabilization after bony apposition was achieved with 6 elastically suspended locking screws. Fracture healing was analyzed weekly on radiographs. After sacrifice 9 weeks postsurgery, the torsional strength of healed tibiae and contralateral tibiae was measured. Finally, computed tomography was used to assess fracture patterns and healing modes. RESULTS:Healing in both groups included periosteal callus formation. ACTIVE specimens had almost 6 times more callus area by week 9 (P < 0.001) than CP specimens. ACTIVE specimens recovered on average 64% of their native strength by week 9, and were over twice as strong as CP specimens, which recovered 24% of their native strength (P = 0.008). Microcomputed tomography demonstrated that compression plating induced a combination of primary bone healing and gap healing. Active plating consistently stimulated biological bone healing by periosteal callus formation. CONCLUSIONS:Compared with compression plating, dynamic stabilization of simple fractures with active plates delivers significantly stronger healing.

BACKGROUNDAxial dynamization of fractures can promote healing, and overly stiff fixation can suppress healing. A novel technology, termed active plating, provides controlled axial dynamization by the elastic suspension of locking holes within the plate. This prospective, controlled animal study evaluated the effect of active plates on fracture-healing in an established ovine osteotomy model. We hypothesized that symmetric axial dynamization with active plates stimulates circumferential callus and delivers faster and stronger healing relative to standard locking plates.METHODSTwelve sheep were randomly assigned to receive a standard locking plate or an active locking plate for stabilization of a 3-mm tibial osteotomy gap. The only difference between plates was that locking holes of active plates were elastically suspended, allowing up to 1.5 mm of axial motion at the fracture. Fracture-healing was analyzed weekly on radiographs. After sacrifice at nine weeks postoperatively, callus volume and distribution were assessed by computed tomography. Finally, to determine their strength, healed tibiae and contralateral tibiae were tested in torsion until failure.RESULTSAt each follow-up, the active locking plate group had more callus (p < 0.001) than the standard locking plate group. At postoperative week 6, all active locking plate group specimens had bridging callus at the three visible cortices. In standard locking plate group specimens, only 50% of these cortices had bridged. Computed tomography demonstrated that all active locking plate group specimens and one of the six standard locking plate group specimens had developed circumferential callus. Torsion tests after plate removal demonstrated that active locking plate group specimens recovered 81% of their native strength and were 399% stronger than standard locking plate group specimens (p < 0.001), which had recovered only 17% of their native strength. All active locking plate group specimens failed by spiral fracture outside the callus zone, but standard locking plate group specimens fractured through the osteotomy gap.CONCLUSIONSSymmetric axial dynamization with active locking plates stimulates circumferential callus and yields faster and stronger healing than standard locking plates.CLINICAL RELEVANCEThe stimulatory effect of controlled motion on fracture-healing by active locking plates has the potential to reduce healing complications and to shorten the time to return to function.

Axial dynamization of an osteosynthesis construct can promote fracture healing. This biomechanical study evaluated a novel dynamic locking plate that derives symmetric axial dynamization by elastic suspension of locking holes within the plate. Standard locked and dynamic plating constructs were tested in a diaphyseal bridge-plating model of the femoral diaphysis to determine the amount and symmetry of interfragmentary motion under axial loading, and to assess construct stiffness under axial loading, torsion, and bending. Subsequently, constructs were loaded until failure to determine construct strength and failure modes. Finally, strength tests were repeated in osteoporotic bone surrogates.One body-weight axial loading of standard locked constructs produced asymmetric interfragmentary motion that was over three times smaller at the near cortex (0.1 +/- 0.01 mm) than at the far cortex (0.32 +/- 0.02 mm). Compared to standard locked constructs, dynamic plating constructs enhanced motion by 0.32 mm at the near cortex and by 0.33 mm at the far cortex and yielded a 77% lower axial stiffness (p < 0.001). Dynamic plating constructs were at least as strong as standard locked constructs under all test conditions. In conclusion, dynamic locking plates symmetrically enhance interfragmentary motion, deliver controlled axial dynamization, and are at least comparable in strength to standard locked constructs. (C) 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.