Steven A. Olson

Post‐traumatic osteoarthritis: Improved understanding and opportunities for early intervention

Even with current treatments of acute joint injuries, more than 40% of people who suffer significant ligament or meniscus tears, or articular surface injuries, will develop osteoarthritis (OA). Correspondingly, 12% or more of all patients with lower extremity OA have a history of joint injury. Recent research suggests that acute joint damage that occurs at the time of an injury initiates a sequence of events that can lead to progressive articular surface damage. New molecular interventions, combined with evolving surgical methods, aim to minimize or prevent progressive tissue damage triggered by joint injury. Seizing the potential for progress in the treatment of joint injuries to forestall OA will depend on advances in (1) quantitative methods of assessing the injury severity, including both structural damage and biologic responses, (2) understanding of the pathogenesis of post‐traumatic OA, taking into account potential interactions among the different tissues and the role of post‐traumatic incongruity and instability, and (3) application of engineering and molecular research to develop new methods of treating injured joints. This paper highlights recent advances in understanding of the structural damage and the acute biological response following joint injury, and it identifies important directions for future research.

Diagnosis and management of closed internal degloving injuries associated with pelvic and acetabular fractures: the Morel-Lavallée lesion.

Closed internal degloving is a significant soft-tissue injury associated with a pelvic trauma in which the subcutaneous tissue is torn away from the underlying fascia, creating a cavity filled with hematoma and liquefied fat. It commonly occurs over the greater trochanter but may also occur in the flank and lumbodorsal region. When this closed internal degloving occurs over the greater trochanter, it is known as a Morel-Lavallée lesion. We reviewed 24 patients who sustained a closed internal degloving injury. Cultures from the closed internal degloving injury were positive in 46% (11 of 24 cases). The incidence of positive cultures was not dependent on the time from injury to debridement. All wounds were treated by thorough debridement before or during pelvic or acetabular surgery. Three patients subsequently developed deep-bone infections, only one of whom had a positive culture at the initial debridement. One patient whose wound was primarily closed over suction drains developed a chronic deep soft-tissue infection requiring multiple debridements. The development of hematoma in the zone of operation reduces the safety of early operative intervention by increasing the risk of infection. An expanding hematoma in a closed internal degloving injury may further compromise the skin vascularity if not promptly drained. The injured soft tissues should be debrided early, either before or at the time of fracture fixation. The wound should be left open, and repeated surgical debridement of the injured tissue is recommended.

Acute Compartment Syndrome in Lower Extremity Musculoskeletal Trauma

Abstract Acute compartment syndrome is a potentially devastating condition in which the pressure within an osseofascial compartment rises to a level that decreases the perfusion gradient across tissue capillary beds, leading to cellular anoxia, muscle ischemia, and death. A variety of injuries and medical conditions may initiate acute compartment syndrome, including fractures, contusions, bleeding disorders, burns, trauma, postischemic swelling, and gunshot wounds. Diagnosis is primarily clinical, supplemented by compartment pressure measurements. Certain anesthetic techniques, such as nerve blocks and other forms of regional and epidural anesthesia, reportedly contribute to a delay in diagnosis. Basic science data suggest that the ischemic threshold of normal muscle is reached when pressure within the compartment is elevated to 20 mm Hg below the diastolic pressure or 30 mm Hg below the mean arterial blood pressure. On diagnosis of impending or true compartment syndrome, immediate measures must be taken. Complete fasciotomy of all compartments involved is required to reliably normalize compartment pressures and restore perfusion to the affected tissues. Recognizing compartment syndromes requires having and maintaining a high index of suspicion, performing serial examinations in patients at risk, and carefully documenting changes over time.

Biomechanical comparison of posterior pelvic ring fixation.

Objective To determine relative stiffness of various methods of posterior pelvic ring internal fixation. Design Simulated single leg stance loading of OTA 61-Cl.2, a2 fracture model (unilateral sacroiliac joint disruption and pubic symphysis diastasis). Setting Orthopaedic biomechanic laboratory. Outcome Variables Pubic symphysis gapping, sacroiliac joint gapping, hemipelvis coronal plane rotation. Methods Nine different posterior pelvic ring fixation methods were tested on each of six hard plastic pelvic models. Pubic symphysis was plated. The pelvic ring was loaded to 1000N. Results All data were normalized to values obtained with posterior fixation with a single iliosacral screw. The types of fixation could be grouped into three categories based on relative stiffness of fixation: For sacroiliac joint gapping, group 1—fixation stiffness 0.8 and above (least stiff) includes a single iliosacral screw (conditions A and J), an isolated tension band plate (condition F), and two sacral bars (condition H); group 2—fixation stiffness 0.6 to 0.8 (intermediate stiffness) includes a tension band plate and an iliosacral screw (condition E), one or two sacral bars in combination with an iliosacral screw (conditions G and I); group 3—fixation stiffness 0.6 and below (greatest stiffness) includes two anterior sacroiliac plates (condition D), two iliosacral screws (condition B), and two anterior sacroiliac plates and an iliosacral screw (condition C). For sacroiliac joint rotation, group 1—fixation stiffness 0.8 and above includes a single iliosacral screw (conditions A and J), two anterior sacroiliac plates (condition D), a tension band plate in isolation or in combination with an iliosacral screw (conditions E and F), and two sacral bars (condition H); group 2—fixation stiffness 0.6 to 0.8 (intermediate level of instability) includes either one or two sacral bars in combination with an iliosacral screw (conditions G and I); group 3—fixation stiffness 0.6 and below (stiffest fixation) consists of two iliosacral screws (condition B) and two anterior sacroiliac plates and an iliosacral screw (condition C). Discussion Under conditions of maximal instability with similar material properties between specimens, differences in stiffness of posterior pelvic ring fixation can be demonstrated. The choice of which method to use is multifactorial.

Timing of fracture fixation in multitrauma patients: the role of early total care and damage control surgery.

&NA; The optimal timing of surgical stabilization of fractures in the multitrauma patient is controversial. There are advantages to early definitive surgery for most patients. Early temporary fixation using external fixators, followed by definitive fixation (ie, the damage control approach), may increase the chance for survival in a subset of patients with severe multisystem injuries. Improved understanding of the pathophysiology of trauma has led to a greater ability to identify patients who would benefit from damage control surgery. A patient is classified as physiologically stable, unstable, borderline, or in extremis. The stable patient can undergo fracture surgery as necessary. An unstable patient should be resuscitated and adequately stabilized before receiving definitive orthopaedic care. The decision whether to perform initial temporary or definitive fixation in the borderline patient is individualized based on the clinical condition. In patients presenting in extremis, lifesaving measures are pivotal, followed by a damage control approach to their injuries.

Comparison of antibiotic beads and intravenous antibiotics in open fractures.

This study compared the efficacy of antibiotic impregnated beads with conventional intravenous antibiotics in the treatment of open fractures. A randomized prospective study was designed and conducted during a 29-month period. Sixty-seven patients with 75 open fractures were treated similarly, with the exception of the method of antibiotic administration, and were followed up for at least 1 year after injury. Infection occurred in two of 24 (8.3%) fractures treated with antibiotic beads alone and in two of 38 (5.3%) fractures treated with conventional intravenous antibiotics. In an unanticipated nonrandomized third cohort group, patients received antibiotic beads and intravenous antibiotics administered for nonorthopaedic reasons or limb threatening injury, or both. Two of 13 (15.4%) fractures in this high risk group became infected. Infection ultimately resolved in all fractures treated with antibiotic beads alone or antibiotic beads in conjunction with conventional intravenous antibiotics. This study was unable to achieve statistical significance; however, the data suggest antibiotic beads may be useful in preventing infection in open fractures. Thus, a larger multicenter randomized prospective study of isolated open fractures, eliminating other variables, is justified.

The development of posttraumatic arthritis after articular fracture

Summary: Posttraumatic arthritis (PTA) is one of the most frequent causes of disability after trauma involving weight-bearing joints and is estimated to be responsible for approximately 10% of the 21 million Americans who have osteoarthritis. Despite a number of similarities in the pathology and end-stage disease of PTA with primary osteoarthritis, the mechanisms involved in the onset and progression of joint degeneration after articular fracture are poorly understood. The largest area of study regarding articular fractures and the development of arthritic changes has focused on the role of adequate surgical reduction of the articular surfaces. However, it is now apparent that a number of complex and interacting biomechanical, biochemical, and, possibly, genetic factors contribute to the development of osteoarthritic changes in the joint after joint trauma, ranging from the cell and molecular level to the joint and systemic level. In this paper, we discuss the potential roles of the initial impact and fracture as well as the subsequent alterations in joint loading, biomechanical and metabolic properties of the cartilage, local and systemic inflammatory cytokines, and viability of chondrocytes in the progression of PTA. An improved understanding of the mechanisms involved in the development of PTA will hopefully lead to the improvement of surgical and nonsurgical therapies for this disease.

Internal fixation of displaced fractures of the sacrum

The results of internal fixation in 30 patients with displaced fractures of the sacrum were retrospectively reviewed. All fractures were displaced at least 1 cm. Neurologic injuries occurred in 40% (12 of 30) patients. In 17 patients who underwent open reduction, the preoperative displacement averaged 24 mm and the postoperative displacement averaged 4 mm. In the 13 patients in whom percutaneous fixation was done, the preoperative displacement averaged 15 mm and the postoperative displacement averaged 5 mm. All 30 fractures united. This review of 30 patients with displaced sacral fractures suggests that open reduction and iliosacral screw fixation leads to better reduction of the fracture site than does closed reduction and percutaneous fixation. Functional assessment indicated that the presence of a neurologic injury is the most important predictor of compromised outcome in patients with displaced sacral fractures.

The computerized tomography subchondral arc: a new method of assessing acetabular articular continuity after fracture (a preliminary report).

Summary: The criteria to treat acetabular fractures operatively versus nonoperatively continue to evolve. The technique of roof arc measurements was developed to identify the extent of superior acetabulum left intact after fracture. Computerized tomography (CT) of the superior 10 mm of the acetabular articular surface evaluates the area equivalent to roof arc measurements of 45°. CT provides increased detail of the superior acetabulum involved with the fracture. Our current criteria for selecting cases for nonoperative treatment are as follows: 1. The acetabular articular surface is intact in the superior 10 mm of the joint on CT evaluation. (Fractures that enter the acetabular fossa, but not the articular surface in the superior 10 mm are included in this group.) 2. The femoral head remains congruent with the superior acetabulum out of traction on the anteroposterior and 45° oblique radiographic views of the pelvis. 3. When a posterior wall fracture is part of the injury pattern, a minimum of 50% of the posterior wall articular surface is intact at the most involved level as determined by CT.

Biomechanical consequences of fracture and repair of the posterior wall of the acetabulum.

We measured the distribution of contact area and pressure between the acetabulum and the femoral head of cadaveric pelves in three different conditions: intact, with an operatively created fracture of the posterior wall, and after anatomical reduction and fixation of the fracture with a buttress plate and interfragmentary screws. The study involved eight cadaveric hip joints from five pelves loaded to 2000 newtons in simulated single-limb stance. Measurements were made with pressure-sensitive film. The acetabulum was divided into three areas--the anterior wall, the superior aspect, and the posterior wall--for the analysis of the data. Creation of a fracture of the posterior wall was followed by an increase in contact area, maximum pressure, and contact force in the superior aspect of the acetabulum. A concomitant decrease in these parameters was observed in the anterior and posterior walls. Anatomical reduction and fixation of the fracture with a plate and screws did not restore the pattern of loading to pre-injury levels.