Bone Morphogenetic Protein-2 Rapidly Heals Two Distinct Critical Sized Segmental Diaphyseal Bone Defects in a Porcine Model.

INTRODUCTION: Segmental bone defects (SBDs) are devastating injuries sustained by warfighters and are difficult to heal. Preclinical models that accurately simulate human conditions are necessary to investigate therapies to treat SBDs. We have developed two novel porcine SBD models that take advantage of similarities in bone healing and immunologic response to injury between pigs and humans. The purpose of this study was to investigate the efficacy of Bone Morphogenetic Protein-2 (BMP-2) to heal a critical sized defect (CSD) in two novel porcine SBD models. MATERIALS AND METHODS: Two CSDs were performed in Yucatan Minipigs including a 25.0-mm SBD treated with intramedullary nailing (IMN) and a 40.0-mm SBD treated with dual plating (ORIF). In control animals, the defect was filled with a custom spacer and a bovine collagen sponge impregnated with saline (IMN25 Cont, n = 8; ORIF40 Cont, n = 4). In experimental animals, the SBD was filled with a custom spacer and a bovine collage sponge impregnated with human recombinant BMP-2 (IMN25 BMP, n = 8; ORIF40 BMP, n = 4). Healing was quantified using monthly modified Radiographic Union Score for Tibia Fractures (mRUST) scores, postmortem CT scanning, and torsion testing. RESULTS: BMP-2 restored bone healing in all eight IMN25 BMP specimens and three of four ORIF40 BMP specimens. None of the IMN25 Cont or ORIF40 Cont specimens healed. mRUST scores at the time of sacrifice increased from 9.2 (±2.4) in IMN25 Cont to 15.1 (±1.0) in IMN25 BMP specimens (P < .0001). mRUST scores increased from 8.2 (±1.1) in ORIF40 Cont to 14.3 (±1.0) in ORIF40 BMP specimens (P < .01). CT scans confirmed all BMP-2 specimens had healed and none of the control specimens had healed in both IMN and ORIF groups. BMP-2 restored 114% and 93% of intact torsional stiffness in IMN25 BMP and ORIF40 BMP specimens. CONCLUSIONS: We have developed two porcine CSD models, including fixation with IMN and with dual-plate fixation. Porcine models are particularly relevant for SBD research as the porcine immunologic response to injury closely mimics the human response. BMP-2 restored healing in both CSD models, and the effects were evident within the first month after injury. These findings support the use of both porcine CSD models to investigate new therapies to heal SBDs.

Internal Fixation Construct and Defect Size Affect Healing of a Translational Porcine Diaphyseal Tibial Segmental Bone Defect.

BACKGROUND AND OBJECTIVE: Porcine translational models have become the gold-standard translational tool to study the effects of major injury and hemorrhagic shock because of their similarity to the human immunologic response to trauma. Segmental bone defects (SBDs) typically occur in warfighters with associated severe limb trauma. The purpose of this study was to develop a translational porcine diaphyseal SBD model in Yucatan minipigs (YMPs), which could be used in bone healing investigations that simulate injury-relevant conditions. We were specifically working toward developing a critical sized defect (CSD). METHODS: We used an adaptive experimental design in which both 25.0 mm and 40.0 mm SBDs were created in the tibial mid-diaphysis in skeletally mature YMPs. Initially, eight YMPs were subjected to a 25.0 mm SBD and treated with intramedullary nailing (intramedullary nail [IMN] 25mm). Due to unanticipated wound problems, we subsequently treated four specimens with identical 25.0 mm defect with dual plating (open reduction with internal fixation [ORIF] 25mm). Finally, a third group of four YMPs with 40.0 mm defects were treated with dual plating (ORIF 40mm). Monthly radiographs were made until sacrifice. Modified Radiographic Union Score for Tibia fractures (mRUST) measurements were made by three trauma-trained orthopedic surgeons. CT scans of the tibias were used to verify the union results. RESULTS: At 4 months post-surgery, mean mRUST scores were 11.7 (SD ± 1.8) in the ORIF 25mm YMPs vs. 8.5 (SD ± 1.4) in the IMN 25mm YMPs (P < .0001). All four ORIF 25mm YMPs were clinically healed. In contrast, none of the IMN 25mm YMPs were clinically healed and seven of eight IMN 25mm YMPs developed delayed wound breakdown. All four of the ORIF 40mm YMPs had flail nonunions with complete hardware failure by 3 months after surgery and were sacrificed early. CT scanning confirmed that none of the IMN 25mm YMPs, none of the ORIF 40mm YMPs, and two of four ORIF 25mm YMPs were healed. A third ORIF 25mm specimen was nearly healed on CT scanning. Inter-rater and intra-rater reliability interclass coefficients using the mRUST scale were 0.81 and 0.80, respectively. CONCLUSIONS: YMPs that had a 40 mm segment of bone removed from their tibia and were treated with dual plating did not heal and could be used to investigate interventions that accelerate bone healing. In contrast, a 25 mm SBD treated with dual plating demonstrated delayed but successful healing, indicating it can potentially be used to investigate bone healing adjuncts or conversely how concomitant injuries may impair bone healing. Pigs treated with IMN failed to heal and developed consistent delayed wound breakdown presumably secondary to chronic limb instability. The porcine YMP SBD model has the potential to be an effective translational tool to investigate bone healing under physiologically relevant injury conditions.

Comparison of submuscular and open plating of pediatric femur fractures: a retrospective review.

BACKGROUND: Plate osteosynthesis is an accepted method of treatment of pediatric femur fractures. Historically, open plating has been used. Submuscular bridge plating has gained recent popularity due to the theoretical advantages of decreased operative time, decreased blood loss, and decreased risk for infection. The purpose of this study was to compare submuscular bridge plating to open plating of pediatric femur fractures. METHODS: We retrospectively reviewed 79 patients (80 treated femur fractures) between 1999 and 2011 that underwent either open plating (58 femur fractures) or submuscular bridge plating (22 femur fractures). The outcome measures evaluated were operative time, estimated blood loss, malunion, leg length discrepancy, time to union, infection, unplanned return to the operating room, and length of hospital stay after surgery. RESULTS: Among our outcome measures, there was no difference between the 2 groups in terms of operative time, leg length discrepancy, time to union, infection, or length of hospital stay after surgery. There was greater estimated blood loss in the open plating group (P≤0.0001) and greater rotational asymmetry in the submuscular bridge plating group (P=0.005). There was a trend of increased unplanned return to the operating room in the open plating group (5/58 vs. 0/22) although not statistically significant (P=0.32). CONCLUSIONS: Submuscular bridge plating and open plating seem to be equally viable options for the management of pediatric diaphyseal femur fractures. In this study, open plating had an increase in estimated blood loss and a trend of more unplanned returns to the operating room, whereas submuscular bridge plating had an increase in asymptomatic rotational asymmetry. Further larger, prospective, randomized studies are necessary to further evaluate these operative techniques. LEVEL OF EVIDENCE: Therapeutic Level III.

Heterotopic ossification in orthopaedic trauma.

Heterotopic ossification (HO) can be defined as the pathologic formation of bone in extraskeletal tissues. There has been a substantial amount of recent research on the pathophysiology, prophylaxis, and treatment of HO and traumatic conditions associated with the development of HO. This research has advanced our understanding of this disease and helped to clarify evidence-based approaches to both the prophylaxis and treatment of HO. This article reviews the literature on these topics with a focus on their application in orthopaedic trauma.

Incisional negative pressure wound therapy after high-risk lower extremity fractures.

OBJECTIVES: To investigate negative pressure wound therapy (NPWT) to prevent wound dehiscence and infection after high-risk lower extremity trauma. DESIGN: Prospective randomized multicenter clinical trial. SETTING: Four Level I trauma centers. PATIENTS/PARTICIPANTS: Blunt trauma patients with one of three high-risk fracture types (tibial plateau, pilon, calcaneus) requiring surgical stabilization. INTERVENTION: Incisional NPWT (Group B) was applied to the closed surgical incisions of patients randomized to the study arm of this trial, whereas standard postoperative dressings (Group A) were applied to the control patients. MAIN OUTCOME MEASURES: Acute and chronic wound dehiscence and infection. RESULTS: Two hundred forty-nine patients with 263 fractures have enrolled in this study with 122 randomized to Group A (controls) and 141 to Group B (NPWT). There was no difference between the groups in the distribution of calcaneus (39%), pilon (17%), or tibial plateau (44%) fractures. There were a total of 23 infections in Group A and 14 in Group B, which represented a significant difference in favor of NPWT (P = 0.049). The relative risk of developing an infection was 1.9 times higher in control patients than in patients treated with NPWT (95% confidence interval, 1.03-3.55). CONCLUSIONS: There have been no studies evaluating incisional NPWT as a prophylactic treatment to prevent infection and wound dehiscence of high-risk surgical incisions. Our data demonstrate that there is a decreased incidence of wound dehiscence and total infections after high-risk fractures when patients have NPWT applied to their surgical incisions after closure. There is also a strong trend for decreases in acute infections after NPWT. Based on our data in this multicenter prospective randomized clinical trial, NPWT should be considered for high-risk wounds after severe skeletal trauma.

Nonunion of a pertrochanteric femur fracture due to a low-velocity gunshot.

The treatment of nonunions often can be a complex and challenging venture. This case report details the treatment of a young patient's pertrochanteric femoral nonunion due to a low-velocity gunshot. Fracture fixation and union were attempted with various implants, including a sliding hip screw, blade plate, and proximal femoral locking plate; however, all eventually failed. Successful union ultimately was obtained only after use of a cephalomedullary nail. There have been few reports in the literature on the failure of proximal femoral locking plates in the treatment of pertrochanteric femur fractures, though much has been published regarding the sliding hip screw and blade plate. Multiple options for use in nonunion surgery were used and discussed in this case, such as autogenous bone graft, bone morphogenic protein, and implantable bone stimulators.

The role of débridement in low-velocity civilian gunshot injuries resulting in pelvis fractures: a retrospective review of acute infection and inpatient mortality.

OBJECTIVES: To determine the use of surgical débridement in the management of low-velocity gunshot injuries (GSIs) resulting in pelvis fractures. DESIGN: : Retrospective chart review. SETTING: Level I trauma center in a major metropolitan area. PATIENTS: Fifty-six patients from 1991 to 2007 treated for pelvis GSIs with resulting pelvis fractures with six acute mortalities and 40 patients with at least 1-year follow-up. INTERVENTION: Patient data were reviewed for incidence of infection related to pelvis GSIs. Information regarding surgical débridement of pelvis GSI wounds, retained foreign bodies, and/or concomitant gastrointestinal (GI) injury was analyzed for relationships of such events to infection rate. MAIN OUTCOME MEASUREMENTS: Incidence of infection related to pelvis GSIs at least 1 year after GSI date. RESULTS: Three patients (6%) developed a deep infection related to their pelvis GSIs. There were no cases of osteomyelitis. The rate of concomitant GI injuries was 36% and the overall infection rate among those with GI injuries was 12% versus 3% for those without a GI injury (P = 0.34). There were infection rates of 7% and 6% among patients who underwent surgical débridement and those who did not, respectively. Of those with GI injuries, 41% underwent primary surgical débridement and none developed infection. In the group of remaining patients with GI injuries who did not undergo débridement of their GSI wounds, two (20%) developed an infection. The mortality rate of low-energy GSIs to the pelvis was six of 53 (11%). CONCLUSION: There was no increased incidence of infection in the absence of aggressive surgical débridement of pelvis GSI wounds. The study also demonstrated that retained bullets and bullet fragments did not increase the risk of infection, even after penetrating the GI tract organs. Finally, this study suggests there may be an increased risk of infection related to pelvis GSIs compared with reported infection rates related to GSIs of the extremities, likely secondary to a high rate of concomitant GI injuries associated with pelvis GSIs; however, there was no incidence of osteomyelitis.

Adult trauma: getting through the night.

It is now recognized that the treatment of many orthopaedic injuries can be, and in many cases should be, deferred until a later date. For example, surgical repair of most fractures of the proximal and distal tibia is now delayed until soft-tissue healing has occurred. Acute treatment involves only provisionally reducing and stabilizing such fractures using a joint-spanning external fixator. However, situations occur in the emergency department in which emergency treatment, even if it is just temporizing in nature, must be done immediately. Often, such treatment is outside the comfort zone of the responsible orthopaedic surgeon, even physicians with training and experience in orthopaedic trauma. Orthopaedic surgeons will benefit from updated information on current methods for the emergency management of limb- and/or life-threatening injuries in adults. Such treatment is often provisional in nature, treating only the urgent component of the injury (such as a compartment syndrome associated with a complex tibial plateau fracture). It is important for orthopaedic surgeons to understand how to get "through the night" so that later appropriate definitive care is facilitated to optimize patient outcomes.

The use of implantable bone stimulators in nonunion treatment.

Delayed or failure of bone healing in fracture, osteotomy, and arthrodesis patients continues to be a clinical dilemma. Electromagnetic stimulation is 1 modality demonstrated in many studies to aid bone healing; however, relatively few studies depict the use and complications associated with direct current implantable bone stimulators. Over a 9-year period, we studied a consecutive series of 120 adult patients who underwent implantation of a direct current bone stimulator. The goals of this study were to determine the time until healing, the presence of infection, and the need for additional nonunion surgery or salvage procedure following internal bone stimulator placement for nonunion treatment. Of the factors affecting the time until healing, tobacco smoking was a significant factor associated with increased time until healing. Tobacco smoking and duration of nonunion prior to implantable bone stimulator placement were both significant factors in the need for revision nonunion surgery or salvage procedure after implantable bone stimulator placement. Deep soft tissue infection or osteomyelitis was a significant factor predicting prolonged time to healing, subsequent infection following implantable bone stimulator placement, and the need for revision or salvage surgery. With the relative lack of complications directly attributable to electromagnetic implantable bone stimulators, their use may be an effective adjuvant to stable internal fixation and autogenous bone grafting in healing nonunions. However, the use of implantable bone stimulators in patients with nonunion prior to deep soft tissue infection or osteomyelitis exhibited an increased rate of postoperative infection in this study.

An analysis of gait changes and functional outcome in patients surgically treated for displaced acetabular fractures.

OBJECTIVES: To determine the relationship between gait, muscle strength, and functional outcome in patients who underwent Open Reduction Internal Fixation (ORIF) of a displaced acetabular fracture using an anterior ilioinguinal approach and to compare gait and functional outcome in patients who have undergone ORIF via an anterior approach with a similar group of patients who have undergone ORIF of a displaced acetabular fracture via a posterior approach and a group of able-bodied cohorts and to investigate relationships between gait, strength, and functional outcome within the entire group of patients. DESIGN: Case series. SETTING: University Medical Center. PATIENTS: Thirty patients were studied, each with an isolated displaced acetabular fracture who were surgically treated; 15 patients were treated using an anterior ilioinguinal approach, and 15 were treated using a posterior Kocher-Langenbeck approach. MAIN OUTCOME MEASURES: Primary outcome measures included gait analysis (speed and kinematics), hip muscle strength, and functional outcome as assessed with the Musculoskeletal Function Assessment (MFA) questionnaire. RESULTS: Several of the limb kinematics for the affected and the unaffected limbs was different when patients treated by an anterior surgical approach were compared with those treated from a posterior approach and able-bodied cohorts. Maximum ankle dorsiflexion was greater in the unaffected limb of the anterior group versus the posterior approach group but was equal to the able-bodied cohorts (AB). Both the affected and the unaffected limbs of the anterior group had larger angles for knee flexion at the time of initial contact compared with the posterior group and AB. Both limbs of the anterior group had significantly more knee flexion and less hip rotation than the posterior group but not from AB. There were no differences in trunk inclination between the surgical groups, but the combined group had greater inclination compared with AB. Average MFA score was 17 +/- 12 (range, 0-47) for the anterior group and 22 +/- 17 (range, 0-57) for the posterior group, respectively. MFA scores did not differ significantly based on surgical approach, fracture pattern, or sex. When gait was compared with MFA scores, an inverse relationship was discovered for the group as a whole. That is, worsening function (increased MFA) correlated with decreased kinematics and stride length. Additionally, greater hip strength was associated with additional hip rotation and increased gait speed. A multivariate regression analysis indicated that both hip rotation (which was associated with hip strength) and hip adductor work strength were important predictors of final MFA scores. CONCLUSIONS: Detailed gait analysis and functional outcome determination indicate that patients treated surgically for a displaced acetabular fracture, either via an anterior or posterior approach, have alterations in their gait, muscle strength, and functional outcome. Maximizing hip muscle strength may improve gait, and improvement in hip muscle strength and gait is likely to improve functional outcome as measured by the MFA. Finally, because both surgical approaches seem to produce the same gait outcomes, it suggests that gait changes after injury and treatment are related to factors other than surgical approach.

Avoiding complications in the treatment of humeral fractures.

Three of the most common complications that may occur after the treatment of humeral fractures are nonunion, loss of fixation, and nerve injury. Nonunion may occur in up to 15% of patients who have been treated surgically. Loss of fixation often is caused by poor quality bone in the osteopenic humeral head. Nerve injury can occur as a result of trauma or from treatment.

Prevention of complications after treatment of proximal femoral fractures.

Two factors are primarily responsible for complications after treatment of proximal femoral fractures. First, the strong deforming forces across the hip joint and proximal femur can make fracture reduction difficult. Second, the placement of the implant affects fracture healing and outcome more dramatically than in other areas of the body. In subtrochanteric fractures, the use of appropriate reduction and stabilization techniques can prevent varus malreduction and subsequent failure of the fixation device. In intertrochanteric fractures, lag screw cutout can be prevented by correct implant positioning. In femoral neck fractures, nonunion can be avoided by careful attention to reduction and hardware positioning.

Prevention of complications after treatment of femoral shaft and distal femoral fractures.

The need for surgical treatment of femoral shaft and distal femoral fractures is undisputed. The treatment options are varied, and often the choice is based on the surgeon's preference rather than orthopaedic science. The decision should be determined by the predicted functional outcome rather than by the type of implant to be used. The entry point for intramedullary femoral nailing is of no consequence, if the nailing is performed correctly and the patient has a good functional outcome. The primary goal of treatment for a supracondylar femoral fracture is to restore limb alignment while preventing angular deformity. Proper technique, not the choice of a nail or plate, is key to recovery.

Avoiding complications in the care of fractures of the tibia.

Tibial fractures are the most common long-bone fractures. Orthopaedic surgeons, regardless of their subspecialty, often must treat these injuries, which range from low-energy, minimally displaced fractures to limb-threatening injuries with neurologic and vascular damage and significant damage to the soft-tissue envelope. Tibial shaft fractures are often prone to complications, such as apex-anterior and valgus malalignments after nailing of the fractures in the proximal one third of the tibia, infection after open fractures, and aseptic nonunions. Understanding the common complications will aid in preventing them and will allow recognition and provide treatment strategies when such problems occur.

Avoiding complications in the treatment of pronation-external rotation ankle fractures, syndesmotic injuries, and talar neck fractures.

Fractures of the foot and ankle are common injuries that often are successfully treated nonsurgically; however, some injuries require surgical intervention. To restore anatomy and avoid the need for additional surgery, surgeons must pay attention to detail and understand common, avoidable complications. The surgeon should have an understanding of the pathologic characteristics of three common injuries of the foot and ankle as well as the potential complications and their prevention.

The management of complications associated with tibial fractures.

Tibial fractures are common and frequently require surgical stabilization. These two factors mean that complications when treating this difficult injury are to be expected. The objectives in the treatment of open tibial shaft fractures are to prevent sepsis, achieve union, and restore function of the limb. However, these goals are often compromised by infection, compartment syndromes, and bone loss associated with many tibial shaft fractures. Recent studies provide a better understanding of the factors involved in the initial care of patients with open tibial fractures and have challenged prior dogmas and practices. An example is studies that define the relationship between the time to débridement of open fractures and subsequent infection. The diagnosis of compartment syndromes continues to be challenging. Careful review of clinical criteria will assist physicians in the early recognition and the management of compartment syndromes. Despite uncomplicated initial care, infections will occur. However, improved knowledge in the basic science of infections, specifically infections about orthopaedic implants, has led to the development of protocols for treatment and obtaining union. Bone loss, a result of either infection or trauma, is one of the most difficult complications to manage. Research regarding bone morphogenesis and the synthesis of multiple compounds has created new options for treating tibial fractures with bone loss.

Fractures of the distal part of the radius. The evolution of practice over time. Where's the evidence?

BACKGROUND: During the administration of the oral (Part II) examinations for the American Board of Orthopaedic Surgery over the past nine years, it has been observed that orthopaedic surgeons are opting more often for open treatment as opposed to percutaneous fixation of distal radial fractures. Evidence to support this change in treatment is thought to be deficient. The present study was designed to identify changes in practice patterns regarding operative fixation of distal radial fractures between 1999 and 2007 and to assess the results of those treatments over time. METHODS: As a part of the certification process, Part II candidates submit a six-month case list to the American Board of Orthopaedic Surgery. In the present study, we searched the American Board of Orthopaedic Surgery Part II database to evaluate changes in treatment over time and to identify available outcomes and associated complications of open and percutaneous fixation of distal radial fractures. All distal radial fractures that had been treated surgically over a nine-year period (1999 to 2007) were reviewed. The fractures were categorized according to fixation method with use of surgeon self-reported surgical procedure codes. Comparisons of percentage treatment type by year were made. Utilization was analyzed by geographic region, and open and percutaneous fixation were compared with regard to complications and outcomes as self-reported by candidates during the online application process. RESULTS: The proportion of fractures that were stabilized with open surgical treatment increased from 42% in 1999 to 81% in 2007 (p < 0.0001). Although the differences were small, surgeon-reported outcomes revealed that a higher percentage of patients who had been managed with percutaneous fixation had no pain and normal function but some deformity as compared with patients who had had open treatment. Patients who had been managed with percutaneous fixation had a higher overall complication rate (14.0% compared with 12.3%; p < 0.006) and a higher rate of infection (5.0% compared with 2.6%; p < 0.0001) than those who had been managed with open treatment. Patients who had had open treatment had a higher rate of nerve palsy and/or injury (2.0% compared with 1.2%; p = 0.001). No other differences in the reported complication rates were found between the two techniques. CONCLUSIONS: A striking shift in fixation strategy for distal radial fractures occurred over the past decade among younger orthopaedic surgeons in the United States. These changes occurred despite a lack of improvement in surgeon-perceived functional outcomes.