AAOS Sports Medicine MCQs (Set 2): Knee Ligament & Rotator Cuff Injuries | Board Review

Margin convergence refers to the phenomenon that occurs with side-to-side closure of large U- or L-shaped rotator cuff tears in which the free margin of the tear converges toward the greater tuberosity as the side-to-side tear progresses. The creation of the converged cuff margin creates decreased strain in the free margin of the repaired cuff, resulting in a decreased strain in the repair sutures. While the size of the humeral head defect is made smaller with side-to-side closure, biomechanically, this is less significant. The mild increase in thickness of the repair at the side-to-side margin is less important than a reduction in stress in the repaired tissue. Stress in the crescent cable region of the cuff actually increases and becomes more physiologic in transmitting force from the cuff to the greater tuberosity. Burkhart SS: A stepwise approach to arthroscopic rotator cuff repair based on biomechanical principles. Arthroscopy 2000;16:82-90.

The number one cause of sudden death in the young athlete is myocardial pathology, with hypertrophic cardiomyopathy being most common. Because of cardiac muscle hypertrophy, the ventricular capacity is diminished and can result in decreased cardiac output. During exertional activities, the increased demand may not be able to be met and leads to sudden death. While the other choices can be the cause of sudden death in an otherwise healthy young athlete, their incidence is even more rare. Van Camp SP, Bloor CM, Mueller FO, et al: Nontraumatic sports death in high school and college athletes. Med Sci Sports Exerc 1995;27:641-647. Maron BJ, Shirani J, Pollac LC, et al: Sudden death in young competitive athletes: Clinical, demographic, and pathological profiles. JAMA 1996;276:199-204.

The patient has myositis ossificans. Rest of the involved area is important to help limit the continued irritation of the muscle, but range-of-motion exercises are important to limit stiffness. While immobilization for 1 or 2 days following a muscle contusion is appropriate, longer periods of immobilization result in muscle atrophy and fibrosis. Injections and irradiation have not been found to be of benefit for myositis ossificans. Excision is rarely required, and if performed, it should not be performed prior to maturation of the lesion, which is a minimum of 6 months. Lipscomb AB, Thomas ED, Johnston RK: Treatment of myositis ossificans traumatica in athletes. Am J Sports Med 1976;4:111-120. Beiner JM, Jokl P: Muscle contusion injuries: Current treatment options. J Am Acad Orthop Surg 2001;9:227-237.

Dorsiflexion of the great toe will accentuate rigidity of the transverse tarsal articulation. Through the windlass mechanism, dorsiflexion of the great toe tightens the plantar fascia, stabilizing the longitudinal arch and placing the foot in supination. Supination makes the talonavicular and calcaneocuboid joints nonparallel, accentuating the rigidity of the transverse tarsal articulation. The heel also tends to go into varus, resulting in obligatory external tibial rotation. Mann RA: Biomechanics of the foot and ankle, in Mann RA, Coughlin MJ (eds): Surgery of the Foot and Ankle, ed 6. St Louis, MO, Mosby, 1993, pp 1-44.

While it is recommended that a patient gain full range of motion, pain-free function, and symmetric strength prior to returning to vigorous activities, it is absolutely essential that radiographs of the fracture site reveal a circumferential external bridging callus to prevent refracture. This is particularly important for comminuted femoral fractures with various sized fragments. It is also recommended that a return to rodeo riding be postponed for at least 1 year. Brumback RJ, Ellison TS: Intermedullary nailing of femoral stress fractures. J Bone Joint Surg Am 1992;74:106-112. Bucholz RW, Jones A: Fractures of the shaft of the femur. J Bone Joint Surg Am 1991;73:1561-1566.

Numerous clinical and basic science investigations have evaluated meniscal tear characteristics to identify factors that either promote or mitigate against meniscal healing. Complex tears have been noted to heal poorly, while longitudinal tears heal more predictably. Tear length, time from injury to repair, medial versus lateral meniscal tears, and the use of a fibrin clot have not been shown to consistently affect meniscal healing. However, rim width, the distance of the tear site from the peripheral meniscocapsular junction (vascular supply), has been shown to have a significant role in the ability of a meniscus repair to heal. DeHaven KE, Arnoczky SP: Meniscus repair: Basic science, indications for repair, and open repair. Instr Course Lect 1994;43:65-76.

All of the tissues noted above are stronger than native ACL. Although it is often thought that the bone-patellar tendon-bone graft is the strongest when selecting a graft source for ACL reconstruction, biomechanical studies show that the quadruple semitendinosus and gracilis tendons are the strongest of the tissues listed. Woo SL, Hollis JM, Adams DJ, et al: Tensile properties of the human femur-anterior cruciate ligament-tibia complex: The effects of specimen age and orientation. Am J Sports Med 1991;19:217-225. Staubli HU, Schatzmann L, Brunner P, et al: Quadriceps tendon and patellar ligament cryosectional anatomy and structural properties in young adults. Knee Surg Sports Traumatol Arthrosc 1996;4:100-110.

The patient has a bipartite patella. The line between the fragment and the main patella is smooth and sclerotic, indicating a chronic, not acute, entity. The location is classic for a bipartite patella, not a tumor. Schmidt DR, Henry JH: Stress injuries of the adolescent extensor mechanism. Clin Sports Med 1989;8:343-355.

The posterior medial approach through the semimembranosus/medial gastrocnemius interval is used in the inlay technique for PCL reconstruction. Exposure of the posterior capsule of the knee through this interval provides the greatest margin of safety to avoid injury to the tibial nerve, motor branch of the medial gastrocnemius, and the peroneal nerve. The direct posterior approach using the medial sural cutaneous nerve allows exposure of the popliteal neurovascular structures, but deep dissection through this interval places the motor branch of the medial gastrocnemius at risk. The interval between the semitendinosus and semimembranosus is used in accessory incisions with medial meniscus repairs but does not allow exposure of the PCL insertion. Berg EE: Posterior cruciate tibial inlay reconstruction. Arthroscopy 1995;11:69-76.

The MRI scan shows a rupture of the patellar tendon. This injury is most appropriately addressed with primary repair. For athletic individuals, the results of nonsurgical management are suboptimal. Reconstructive procedures are not necessary. Matava MJ: Patellar tendon ruptures. J Am Acad Orthop Surg 1996;4:287-296.

The patient has primary scapulotrapezius winging caused by surgical damage to the spinal accessory nerve during a lymph node biopsy. Other causes include blunt trauma, traction, and penetrating injuries. With spinal accessory palsy, the shoulder appears depressed and laterally translated because of unopposed serratus anterior muscle function. With primary serratus anterior winging that is the result of long thoracic nerve palsy, the scapula assumes a position of elevation and medial translation with the inferior angle rotated medially. The thoracodorsal nerve innervates the latissimus dorsi and is not associated with scapular winging. Kuhn JE, Plancher KD, Hawkins RJ: Scapular winging. J Am Acad Orthop Surg 1995;3:319-325.

A rib stress fracture, the most common injury to the thorax in rowing athletes, generally occurs during periods of intense training with a low stroke rate and heavy loads. It is characterized by the sudden onset of sharp, localized chest pain while rowing. The fifth through the ninth rib is generally affected, and the diagnosis is best established with a bone scan. An intercostal muscle strain generally has an insidious onset and may be poorly localized. Costochondritis affects the anterior costochondral junction. A pneumothorax and an empyema can cause nonlocalized chest pain but are associated with respiratory distress and systemic physical findings. Karlson KA: Rib stress fractures in elite rowers. Am J Sports Med 1998;26:516-520.

The anterior cruciate ligament is attached to a portion of the lateral femoral condyle. The posterior cruciate ligament attaches to the medial femoral condyle. The lateral collateral and oblique popliteal ligaments attach proximal to this fragment. The intermeniscal ligament attaches the anterior horns of the menisci. Jobe CM, Wright M: Anatomy of the knee, in Fu FH, Harner CD, Vince KG (eds): Knee Surgery. Baltimore, MD, Williams & Wilkins, 1994, pp 1-54.

Growth hormone is the most abundant substance produced by the pituitary gland. Growth hormone has a direct anabolic effect by accelerating the incorporation of amino acids into proteins. It is becoming an increasingly popular anabolic steroid substitute; however, it is expensive and difficult to obtain. Androstenedione is an androgen produced by the adrenal glands and gonads. It acts as a potent anabolic steroid and is converted in the liver directly to testosterone with a resultant increase in levels after administration. DHEA is a naturally occurring hormone made by the adrenal cortex. It is converted to androstenedione, which in turn is converted to testosterone. The beneficial and adverse effects of DHEA can be correlated directly with those of testosterone. Nandrolone is also a potent anabolic steroid. It is commonly taken as 19-norandrostenedione and may be more favored because of its potent anabolic effects with less androgenic effects (no conversion to estrogen compounds). Creatine sales have skyrocketed, and it is a popular nutritional supplement. There is an expectation that creatine can increase strength and power performance; however, direct anabolic effects have not been demonstrated. Creatine serves as a substrate for hydrogen ions and contributes to the resynthesis of ATP (adenosine triphosphate) during maximal exercise. By enhancing ATP production and buffering local pH in muscle, there may be improved tolerance of anaerobic activities. Increases in muscle mass may be related to increased perception of improved training ability or an increase in muscle water content. Silver M: Use of ergogenic aids by athletes. J Am Acad Orthop Surg 2001;9:61-70.

A superior labrum, when intact, stabilizes the shoulder by increasing its ability to withstand excessive external rotational forces by an additional 32%. The presence of a SLAP lesion decreases this restraint and increases the strain in the superior band of the inferior glenohumeral ligament by over 100%. Rodosky MW, Harner CD, Fu FH: The role of the long head of the biceps muscle and superior glenoid labrum in anterior stability of the shoulder. Am J Sports Med 1994;22:121-130.

The MRI scan shows a rupture of the Achilles tendon. The substantiated advantages of repair are less risk of re-rupture and greater plantar flexion strength. Dorsiflexion strength is not influenced. Motion, pain, and period of recovery are not specifically improved as a consequence of surgery. Bhandari M, Guyatt GH, Siddiqui F, et al: Treatment of acute Achilles tendon ruptures: A systematic overview and meta-analysis. Clin Orthop 2002;400:190-200.

Traumatic dislocation of the hip in sports injuries is uncommon, and 85% to 92% occur in a posterior direction. In dislocations without fractures, osteonecrosis is the most common complication occurring in 10% to 20% of patients. MRI should be performed at 3 months postreduction to rule out osteonecrosis. Nerve injuries are rare in this setting, and recurrent dislocations are unusual without acetabular fractures. Chondrolysis has been reported as a rare occurrence. Anderson K, Strickland S, Warren R: Hip and groin injures in athletes. Am J Sports Med 2001;29:521-533.

In the adolescent population, a lumbar herniated disk is characterized by a paucity of clinical findings, with a positive straight leg raising test the only consistently positive finding. This may result in a prolonged period of nonsurgical management that fails to provide relief. Activities that place a significant shear load on the lumbar spine, such as the dead lift, are associated with an increased risk of central disk herniation. An adolescent who lifts weights and has a history of back pain that fails to respond to a short period of active rest should undergo MRI evaluation for the diagnosis of a lumber herniated disk. Epstein JA, Epstein NE, Marc J, et al: Lumbar intervertebral disk herniation in teenage children: Recognition and management of associated anomalies. Spine 1984;9:427-432.

The patient has patellar tendinitis (jumper's knee). It is a common overuse condition seen in runners, volleyball players, soccer players, and jumpers but can be seen in any activity in which repeated extension of the knee is required. In the acute setting, the pain is well localized and there is tenderness and sometimes swelling of the tendon. MRI is recommended for evaluating chronic cases and for surgical planning. In the acute phases, ice, rest, and avoidance of the offending activity are recommended. Weakness of the quadriceps and hamstring muscle are thought to contribute to this problem; therefore, stretching and isometric exercise in a limited range of motion are important. Complete rest and intratendinous injections of steroids are detrimental to tendon physiology. Stanish WD, Rubinovich RM, Curwin S: Eccentric exercise in chronic tendinitis. Clin Orthop 1986;208:65-68.

Left ventricular hypertrophy by voltage is a nonspecific diagnosis, especially in athletes with an asthenic body habitus. High vagal tone in endurance athletes may result in first degree or even type I second degree (ie, Wenckebach) AV block in endurance athletes. High vagal tone results in resting sinus bradycardia in many trained athletes. A I-II/IV systolic ejection murmur is occasionally found in healthy athletes; however, when the murmur increases in intensity with maneuvers that decrease ventricular filling, such as standing or the Valsalva maneuver, dynamic obstruction that is the result of hypertrophic obstructive cardiomyopathy should be suspected. Nonspecific STT wave changes in the lateral leads on ECG are not uncommon in highly trained athletes; thus, they are nonspecific for ischemic heart disease. Pelliccia A, Maron BJ, Culasso F, DiPaolo FM, et al: Clinical significance of abnormal electrocardiographic patterns in trained athletes. Circulation 2000;102:278-284.

Mallet fingers without DIP joint subluxation can be treated with extension splinting. Surgical fixation may be necessary in bony mallet injuries when the joint is subluxated. Size of the bony fragment, while often correlating with stability, is not always an indication for fixation. Buddy taping allows motion; therefore, the fragment will not heal in the appropriate position. Intermittent splinting with range-of-motion exercises also will not allow the fragment to heal in the appropriate position. Crawford GP: The molded polyethylene splint for mallet finger deformities. J Hand Surg Am 1984;9:231-237.

With a full-thickness articular cartilage injury, a healing response is initiated with hematoma, stem cell migration, and vascular ingrowth. This response produces type I collagen and resultant fibrous cartilage rather than desired hyaline cartilage as produced by chondrocytes. This repair cartilage has diminished resiliency, stiffness, poor wear characteristics, and the predilection for arthritis. Type I collagen is also found in the annulus of intervertebral disks, tendon, bone, meniscus, and skin. Type II is found in articular cartilage and nucleus pulposus of intervertebral disks. Type III is found in skin and blood vessels, type IV is found in basement membranes, and type X is found in the calcified layer of cartilage. Arendt EA (ed): Orthopaedic Knowledge Update: Sports Medicine 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 19-28.

Anteromedial displacement of the tibial tubercle unloads the distal and lateral facets of the patella and shifts the forces to the proximal and medial facets. Therefore, if findings indicate arthrosis predominately in the medial and proximal areas of the patella, this is considered a relative contraindication because it may accentuate arthritic symptoms. Fulkerson JP: Anteromedialization of the tibial tuberosity for patellofemoral malalignment. Clin Orthop 1983;177:176-181. Bellemans J, Cauwenberghs F, Witvrouw E, et al: Anteromedial tibial tubercle transfer in patients with chronic anterior knee pain and a subluxation-type patellar malalignment. Am J Sports Med 1997;25:375-381.

Hamstring strains are common in athletes. Basic science research and clinical data indicate that the majority of these injuries occur at the myotendinous junction, not within the muscle belly. Avulsion of hamstring origin from the ischial tuberosity does occur but is less common. Complete tearing of all hamstring muscles is unlikely to occur. Griffin LY (ed): Orthopaedic Knowledge Update: Sports Medicine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1994, pp 17-33.

The injury mechanism involves a valgus load applied to the knee with the foot in external rotation. The primary stabilizer to valgus laxity is the medial collateral ligament. The secondary restraints to valgus rotation are the cruciate ligaments. Examination indicates disruption of the medial collateral and anterior cruciate ligaments. Valgus opening in extension should also arouse suspicion for an injury to the posterior cruciate ligament; however, in this patient, the valgus opening in extension is mild. The slight opening in extension and the increased anterior drawer, especially with external rotation, indicates disruption of the posteromedial capsule and posterior oblique ligament. Figure 21a shows complete disruption of the superficial and deep medial collateral ligaments involving the meniscofemoral ligament. Figure 21b shows a more posterior coronal section with a torn posterior oblique ligament. Figure 21c shows disruption of the anterior cruciate ligament, while the posterior cruciate ligament at the tibial insertion appears with a homogenous normal signal. Warren LA, Marshall JL, Girgis F: The prime static stabilizer of the medial side of the knee. J Bone Joint Surg Am 1974;56:665-674.