2. Trauma MCQs

DISCUSSION: Contracture of the intrinsic flexor muscles of the foot can be the result of unrecognized foot compartment syndrome. Foot compartment syndrome is a known complication of calcaneus fractures. Myerson reported 3/43 patients in his series had chronic foot compartment syndrome. There are 9 compartments in the foot: (1) medial, (2) superficial, (3) lateral, (4) adductor, (5-8) four interossei, and (9) calcaneal. The plantar fascia limits the space available for hematoma and swelling, causing damage to the intrinsic flexors of the foot (particularly the lumbricals and interossei), resulting in clawtoes.

The Investigators Randomized Trial of Reamed versus Non-Reamed Intramedullary Nailing of Tibial Shaft Fractures (SPRINT) study, a large, randomized, controlled trial, has shown a benefit of reamed intramedullary (IM) nailing versus unreamed IM nailing for closed tibial shaft fractures with regard to reoperation rates. No such association exists for open tibial fractures; ie, union rates are the same for open fractures. The infection rates are the same, as is functional outcome, and surgical time is potentially shorter for unreamed nails. The potential pulmonary benefits from unreamed nailing have never been clinically proven.

Pin track infections and sensory injuries are among the most common complications of external fixation for distal radius fractures. The proximal pins of most distal radius external fixators are placed in the “bare area” of the distal radius, about four finger-breadths above the radial styloid. This corresponds to the area where the dorsal sensory branch of the radial nerve penetrates the fascia dorsal to the brachioradialis tendon to become a subcutaneous structure. Injury to the superficial radial nerve may produce painful dysesthesias and neuromas.(SBQ12TR.106) A 67-year-old female sustains the injury shown in Figure A after a trip and fall. When discussing the outcomes of surgery with the patient, which of the following statements is true?Post-surgical mortality rates are significantly lower after total hip arthroplasty compared to hemiarthroplastyInternal fixation shows better outcomes (reoperation rate, functional status, and/or complication rates) compared to arthroplastyBipolar hemiarthroplasty shows better outcomes (reoperation rate, functional status, and/or complication rates) compared to unipolar hemiarthroplastyA delay in surgery greater than 48 hours is recommended if the patient has multiple medical comorbiditiesm which are not fully optimizedDislocation rates are equivalent between total hip arthroplasty and hemiarthroplastyModerate evidence supports that hip fracture surgery within 48 hours of admission is associated with better outcomes. However, patients with significant medical comorbidity should be fully optimized before surgery.Although several studies have shown a benefit to surgery within 48 hours, no definitive time frame has been elucidated. The majority of literature has shown improved outcomes in regards to pain, complications, and length of stay with early surgery. Patients with significant medical comorbidities have been shown to have the highest mortality rates.Moran et al. aimed to determine whether a delay in surgery for hip fractures had an affect on postoperative mortality among elderly patients. In an observational study of 2660 patients, they showed that mortality following hip fracture surgery was 9% at 30-days, 19% at 90-days, and 30% at 12-months. Patients with medical comorbidities had 2.5 times the risk of death within 30-days of surgery. In addition, individuals who had surgery delayed beyond 4 days had increased mortality at 90-days and 12-months.Papakostidis et al. examined the timing of internal fixation of intracapsular fractures of the neck of femur on the development of late complications, particularly osteonecrosis of femoral head (ONFH) and non-union. They showed no benefit ofearly surgery on incidence of AVN. However, delay of internal fixation of more than24 hours showed increased rates of non-union.Figure A shows a displaced right femoral neck fracture. Incorrect Answers:

Bhandari and associates, in a meta-analysis, concluded that sufficient evidence exists to suggest that reamed intramedullary nailing of lower extremity long bone fractures significantly reduces rates of nonunion and implant failure in comparison with nonreamed nailing. Tornetta and Tiburzi, in a prospective randomized study, determined that reamed canal preparation led to faster healing of distal fractures treated with statically locked intramedullary nails. Blood loss was greater in the reamed group, but this did not translate into increased transfusion requirements. In this series, there was no advantage to nail insertion without reaming. In a prospective randomized multicenter study, the overall incidence of acute respiratory distress syndrome (ARDS) was found to be low with primary stabilization of femoral shaft fractures with intramedullary nailing. There was no difference in the incidence of ARDS between the reamed and unreamed groups. In a retrospective study performed by Handolin and associates, intramedullary nailing of long bone fractures in patients with multiple injuries and with a coexisting pulmonary contusion did not impair pulmonary function or outcome. No study has convincingly demonstrated an increased trend toward infection with reamed femoral intramedullary nailing.

In the direct anterior approach, achieving adequate femoral exposure requires displacing the femur anteriorly and laterally. As the femur is externally rotated and elevated, the greater trochanter moves posteriorly towards the ilium/posterior acetabulum. Without adequate release of the superior/posterior capsule and short external rotators (like the piriformis), excessive force with the femoral hook causes the greater trochanter to impinge, leading to a fracture of the greater trochanter.

The finding described is the Hawkins sign. It is a subchondral radiolucency in the talar dome that typically appears 6 to 8 weeks after injury. It represents subchondral osteopenia secondary to disuse and active hyperemia, which requires intact vascularity. Thus, a positive Hawkins sign is a highly reliable indicator that the talar body is viable and that widespread avascular necrosis (AVN) will not occur.

A true Jones fracture (Zone 2) occurs at the metaphyseal-diaphyseal junction of the fifth metatarsal. This specific region is a vascular watershed area. The tuberosity (Zone 1) is richly supplied by metaphyseal arteries, and the diaphysis (Zone 3) is supplied by the nutrient artery (which enters medially and branches proximally and distally). Zone 2 lies at the tenuous junction of these two blood supplies, making it highly susceptible to delayed union or nonunion.

Pelvic discontinuity is defined as a complete transverse separation of the superior hemipelvis (ilium) from the inferior hemipelvis (ischium and pubis) resulting from an ununited fracture or severe bone loss directly through the acetabulum. Treatment usually requires complex reconstruction such as custom triflange implants, cup-cage constructs, or distraction osteogenesis to bridge the defect.

The best method of evaluating the acuity of osteoporotic compression fractures is to look for edema in the vertebral body. This is best accomplished with a STIR-weighted MRI scan. Bone scans can show increased uptake at the site of fracture for many months after the fracture. T1-weighted MRI scans show loss of normal marrow fat that may not necessarily correspond with acuity of the fracture. CT scans and radiographs show fracture deformity but cannot be used to judge acuity.

This child's radiograph shows an acceptably reduced fracture of both the radius and ulna. Generally accepted limits of shaft angulation for cast treatment for girls 8 years of age or younger and boys age 10 or younger are 20 degrees for distal-third, 15 degrees for middle-third, and 10 degrees for proximal-third fractures. Remodeling decreases as one goes from distal to proximal in the forearm. Unless the child's fracture deviates from these criteria, surgical treatment is not necessary. Because of the risk of displacement, however, close follow-up is recommended.

Unlike compression-side stress fractures, tension-side stress fractures on the superior side of the femoral neck are at a very high risk of displacement, even if the patient is not bearing weight. It is highly recommended to treat these fractures like acute fractures and to proceed with internal fixation emergently. Once the fracture has displaced, the prognosis is poor in terms of returning to sports, even when reduced and internally fixed. Nonsurgical management, such as limited weight bearing and low-impact activities, works very well for other lower extremity stress fractures. A training program evaluation (shoes, tracks, schedule) is always indicated for all patients with stress fractures.

Fractures of the proximal tibial shaft are associated with high rates of valgus and apex anterior (procurvatum) malalignment.Proximal third tibial shaft fractures are often difficult to reduce anatomically due to the tendency for both valgus and flexion deformity at the fracture site. Many different techniques have been devised to overcome the deforming forces. These include (1) Poller blocking screws posterior and lateral to the intramedullary nail (IMN), (2) utilizing a semiextended knee position during IMN of proximal tibia fractures (3) use of a suprapatellar approach for IMN, (4) usage of a slightly more lateral starting point during conventional IMN, and (5) application of unicortical plate.Ricci et al. describe the technique and results of using blocking screws and intramedullary nails to treat patients with fractures of the proximal third of the tibia. Post-operatively, all patients in their series had less than 5 degrees of angular deformity in the planes in which blocking screws were used to control alignment. At 6 months follow-up, 10/11 patients maintained this alignment.Illustration A shows intra-operative sagittal radiographs of the proximal tibia. Note the use of Poller blocking screws in the posterior and lateral aspects of the proximal tibia.Incorrect Answers:

DISCUSSION: The ASA classification (detailed in Illustration A) was initially developed in 1963 and has been shown to be predictive of post-surgical mortality in hip fracture patients. Basic categories are as follows: 1= normal, healthy; 2= mild systemic disease; 3= severe systemic disease, not incapacitating; 4= severe incapacitating systemic condition, constant threat to life; 5= moribund patient; 6 = brain dead, organs being donated. The study by Richmond et al looked at 836 patients treated for a hip fracture and found that this injury is not associated with significant excess mortality amongst patients older than age 85. However, in younger patients, those with ASA classifications of 3 or 4 have significant excess mortality following hip fracture that persists up to 2 years after injury.

PHASE V: the crescent sign and articular collapse. The supporting bony architecture may become sufficiently weakened by continued resorption of trabecular bone and subchondral bone plate along the reactive interface that the stress of weight-bearing can result in subchondral bone plate fracture with focal articular cartilage buckling and eventual collapse. This is best seen in the frog-lateral radiograph.

DISCUSSION: When substantial lengthening of a dysplastic hip will occur because a high dislocation is relocated into a considerably lower acetabulum, a femoral shortening may be necessary to reduce the hip and avoid a stretch injury to the sciatic nerve. No other choice specifically addresses the need for femoral shortening, and high offset stems and lateralized liners may exacerbate the problem if used alone and without femoral shortening.

DISCUSSION: The radiograph shows an avulsion fracture, or “sleeve fracture,” of the distal pole of the patella. The distal fragment is much larger than it appears on the radiograph because it largely consists of cartilage; therefore, excision of the fragment is contraindicated. The treatment of choice is open reduction and tension band fixation to correct patella alta and restore the extensor mechanism. REFERENCES: Maguire JK, Canale ST: Fractures of the patella in children and adolescents. J Pediatr Orthop 1993;13:567-571. Grogan DP, Carey TP, Leffers D, et al: Avulsion fractures of the patella. J Pediatr Orthop 1990;10:721-730.

DISCUSSION: Fractures above and below the elbow constitute floating elbow injuries and are best treated with internal fixation to allow early range of motion and to prevent elbow stiffness. Use of a long arm cast would promote elbow stiffness. External fixation is indicated primarily for open injuries. REFERENCES: Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 271-286. Bell MJ, Beachamp CG, Kellam JK, McMurtry RY: The results of plating humeral shaft fractures in patients with multiple injuries: The Sunnybrook experience. J Bone Joint Surg Br 1985;67:293-296.

The diagnostic criteria for chronic exertional compartment syndrome is pressure >15 mm Hg at rest, or>30 mm Hg at 1 minute post exercise, or >20 mm Hg at 5 minutes post-exercise. The anterior and lateral compartments are the only ones that meet strict diagnostic criteria for chronic exertional compartment syndrome. The superficial posterior compartment, although close to meeting criteria, is not responsiblefor the patient's symptoms and falls below current thresholds for diagnosis.

DISCUSSION: A delta P (diastolic blood pressure minus compartment pressure measurement) of < 30 mmHg is an indication for fasciotomies with the caveat that the diastolic pressure is measured either pre- or postoperatively. Given the poor outcomes associated with missed compartment syndromes, it is important to obtain both clinical and objective data when determining if a patient needs fasciotomies. Determining if a patient needs fasciotomies in the operating room while a patient is under anesthesia is complicated by the fact that obtaining a clinical exam is impossible, and that the diastolic blood pressure may be falsely decreased compared to normal pre- or postoperative measurements. Currently, it is recommended that intraoperative compartment pressures be compared to preoperative diastolic blood pressures, with delta p < 30 indicating the need for fasciotomies. Kakar et al. review the preoperative, intraoperative, and postoperative diastolic blood pressure (DBP) in 242 patients with a tibia fracture treated operatively. They found the mean DBP was 18 points lower in the operating room compared to the preoperative measurement. In addition, they found the difference between preoperative and postoperative diastolic blood pressures to be within 2 points, indicating the decrease seen intraoperatively is likely a spurious value induced by anesthetic. McQueen and Court-Brown prospectively review 116 patients with tibia fractures that had continuous monitoring of their anterior compartment for 24 hours. They found that using an absolute pressure of 30 mmHg would have resulted in 50 patients (43%) treated with unnecessary fasciotomies. They conclude using a differential pressure of 30 mmHg is a more reliable indicator of compartment syndrome.

EXPLANATION: This is a transverse proximal phalanx fracture with apex volar angulation. The fracture displaces into an apex volar angulated position under the pull of the central slip on the distal fragment and the interossei insertions at the base of proximal phalanx. Although it is possible to lose motion in flexion or extension of the MP or PIP joints, the biomechanics will not allow full extension of the PIP joint. If allowed to heal in apex palmar malunion, the predicted corresponding extensor lags are for a 10-degree lag at 16 degrees of angular deformity, a 24-degree lag at 27 degrees of deformity, and a 66-degree lag at 46 degrees of deformity. These fractures usually can be treated with closed reduction with or without percutaneous pinning. With surgical treatment, there may be loss of motion both at the MP and PIP joints.