Orthopedics

21 Orthopedics



Children with musculoskeletal injuries and afflictions are brought for care because of pain, deformity, or loss of function. Often the clinical challenge lies not so much in recognizing the impaired or injured part, which in most cases is readily accessible to inspection and examination, but in making an accurate diagnosis in order to plan and initiate appropriate treatment. Because of their rapid physical growth and the special properties of their developing bones, children often pose special problems for the clinician.


Musculoskeletal problems in children fall into several general categories.



This chapter focuses on primary musculoskeletal problems, and the discussion is divided into eight sections: (1) development of the skeletal system, (2) physical assessment, (3) musculoskeletal trauma, (4) disorders of the neck and spine, (5) disorders of the upper extremity, (6) disorders of the lower extremity, (7) generalized musculoskeletal disorders, and (8) sports medicine.



Development of The Skeletal System


The assessment, diagnosis, and management of pediatric orthopedic problems necessitate a clear understanding of the physiology of the growing musculoskeletal system and especially of the unique properties of growing bone. The process of growth begins in utero and continues until the end of puberty. Linear growth occurs as the result of multiplication of chondrocytes in the epiphyses, which align themselves vertically, forming a transitional zone of endochondral ossification in the metaphyses. The shafts of long bones widen, and flat bones enlarge through the deposition and mineralization of osteoid by the periosteum. Hence genetic and congenital disorders that affect connective tissue (and thus the skeleton) tend to cause abnormal growth. Most commonly this results in dwarfism, with varying degrees of deformity. However, in some conditions such as Marfan syndrome, excessive linear growth occurs, resulting in an abnormally tall stature and unusually long fingers and toes.


The terminal arterial loops and sinusoidal veins that form the vascular bed of growing metaphyses have sluggish blood flow, which increases the risk of thrombosis and of the deposition of bacteria during periods of bacteremia. As a result, there is a greater risk of developing hematogenous osteomyelitis in pediatric patients than in adults. Furthermore, the epiphyseal plates, which are incompletely formed in infancy, are a less effective barrier to extension of infection into adjacent joints, and the relatively thin diaphyseal cortices tend to permit rupture outward under the overlying periosteum. Similarly, penetration of vascular channels through the vertebral end plates into the intervertebral disks makes diskitis more likely than vertebral osteomyelitis in early childhood (see Chapter 12).


A thorough understanding of musculoskeletal development and of the radiographic findings at differing stages is particularly important in the diagnosis and management of orthopedic injuries. At birth only a few epiphyses have begun to ossify; the remainder are cartilaginous and thus are invisible radiographically. With development, other epiphyses begin to ossify, enlarge, and mature in such an orderly fashion that one can estimate a child’s age from the number and configuration of ossification centers (Figs. 21-1 and 21-2). The epiphyseal plates (physes), which are sites of cartilaginous proliferation and growth, do not begin to ossify and thereby close until puberty (Fig. 21-3). This process starts and ends earlier in girls than in boys. When skeletal injuries involve sites where ossification has not begun or is incomplete, radiographic findings may appear normal or may not reflect the full extent of the injury. This necessitates greater reliance on clinical findings. Magnetic resonance imaging (MRI) can be of assistance in defining unossified or incompletely ossified structures.





Before closure of the physis during puberty, the growth plate is actually weaker than nearby ligaments. As a result, injuries that occur near joints are more likely to result in physeal disruption than in ligamentous tearing (i.e., sprains and dislocations are seen less commonly in prepubescent children than in adolescents and adults). Similarly, avulsion fractures at sites where strong muscular attachments join secondary ossification centers are unique to children and adolescents. When there is displacement of an epiphyseal fracture and the fragments are not anatomically reduced, growth disturbances may occur. Because the epiphysis may not be ossified, radiographs often fail to reveal the injury, and for this reason children with injuries at or near joints must be examined with meticulous care so that epiphyseal fractures are not missed. Clinically, pain and swelling may be detected over the epiphyseal plate region and, less notably, over the joint itself.


The periosteum of a child is much thicker than that of an adult, strips more easily from the bone, and is rarely disrupted completely when the underlying bone is fractured. Because of the immature elements in the rapidly growing skeleton of the child, the bone has more viscoelasticity and can sustain plastic deformation more easily than the adult skeleton. Consequently, a given compressive force that would produce a comminuted fracture in an adult tends to be dissipated in a child in part by the bending that occurs in the more flexible bone of the child. Such a force is thus more likely to result in plastic deformation or to produce an incomplete fracture, such as a torus fracture or a greenstick fracture, in a child.


Thus fracture patterns in children often differ from those in adults. Their fractures can be considerably more difficult to detect clinically and radiographically, and because the growing cells in the epiphyseal plate may be injured, growth disturbances may occur. Children do have advantages, however, in that their actively growing bones heal more rapidly and have a remarkable capacity for remodeling.


Finally, numerous genetic, metabolic, endocrine, renal, and inflammatory processes can affect not only growth and ultimate height but also skeletal maturation—in some cases delaying it and in others accelerating it. Comparison of the patient’s actual bone age, as determined by the number of radiographically visible ossification centers, with his or her chronologic age can help in the diagnosis of these underlying disorders.



Physical Assessment



History


Key historical points in the evaluation of problems not resulting from trauma include the following:



This information helps considerably in narrowing the list of differential diagnostic possibilities.


When the patient’s problem is the result of trauma, it is important to obtain the following historical points:



This information helps localize the site or sites of injury and potential injury severity, points to the risk of possible associated injuries, gives clues to the possible existence of underlying disorders that may predispose to injury, and may occasionally raise a suspicion of abuse.



Physical Examination


The orthopedic examination involves a systematic assessment of posture, stance, and gait; the symmetry or asymmetry of paired musculoskeletal structures and their motion; muscle strength and tone; and neurovascular status. In pediatrics, the patient’s developmental level is a major consideration, not only in terms of the interpretation of findings, but also in terms of the manner in which the examination is conducted. Patience and often some degree of creativity are required on the part of the examiner if the patient is very young. Often, much information can be gleaned from an initial period of observation of the child’s demeanor and spontaneous activity. This can be assisted by providing age-appropriate toys for him or her to play with while the history is being taken and by engaging the patient in play (if circumstances permit) before starting the more formal physical examination. This also helps to alleviate anxiety and gain the child’s trust, enhancing his or her cooperation. As in all examinations of infants and children, taking time to establish the child’s trust in the examiner is helpful. After spontaneous activity is observed, the relevant parts of the orthopedic examination are typically done by region.


A complete orthopedic examination that assesses each bone, muscle, joint, tendon, and ligament is lengthy, detailed, and rarely indicated. Even in multiple-trauma victims and patients whose symptoms point toward an underlying systemic disorder, each region is screened and a full assessment done only of those regions where local musculoskeletal abnormalities are found. Similarly, in patients with focal injuries or deformities, the examination can generally be focused on the region involved, with the clinician bearing in mind referral patterns for pain and the maxim that all extremities “begin at the back.” Finally, in performing routine physical examinations on healthy children, after a general screening examination of spontaneous movement, posture, gait, station, and stance, the assessment of the musculoskeletal system is focused on areas at risk for the child’s age (e.g., the hip for dislocation in the neonate, the spine for scoliosis in the preadolescent and adolescent).



Regional Musculoskeletal Examination


In the regional examination the area of concern is inspected visually for spontaneous movement, guarding, size, swelling, deformity, and the appearance of overlying skin, and the findings are compared with those for its paired structure. After this, the normal side and then the affected side are gently palpated for warmth, induration, and tenderness. Muscle mass, tone, and reflexes on the affected side are compared with those on the normal side, and the presence or absence of spasm is noted. If asymmetry in muscle mass is detected, the circumference is measured bilaterally at a point equidistant from a fixed bony landmark. The child is then asked to move the extremity or is handed objects to get him or her to do so, and active motion is observed. If this appears limited, passive range of motion is tested first on the normal and then on the affected side, taking care not to cause severe pain. Strength is tested against gravity and then against resistance (Table 21-1), being careful to stay within the limits of pain. Then sensation and vascular status are also evaluated.


Table 21-1 Grading of Muscle Strength
























Grade Physical Finding
0/5 No movement seen
1/5 Muscle can move joint with gravity eliminated
2/5 Muscle can move joint against gravity but not against added resistance
3/5 Muscle can move joint against slight resistance
4/5 Muscle can move joint against moderate added resistance
5/5 Normal strength

Joints are further inspected to determine whether there is erythema, obliteration of landmarks that may indicate the presence of effusion, evidence of deformity, and position of comfort. Further evaluation to detect joint effusion is done by pressing on one side of a visible joint while feeling for the protrusion of fluid on the other. The joints are palpated to check for evidence of heat and tenderness, range of motion is assessed, and evidence of pain on motion is determined.


Assessment of ligamentous stability around joints is discussed under specific sections of the regional examination. However, it is important to remember that in cases of acute trauma, especially when deformity or hemarthrosis is evident on initial assessment, tests of ligamentous stability should be deferred, the extremity splinted, and radiographs obtained to check for possible underlying fracture.



Axial Skeleton and Upper Extremity Examination



Trunk and Neck

With the examiner in front and the patient standing, the sternocleidomastoid muscles, the bony prominences of the clavicles, and the respective heights of the acromioclavicular joints, nipples, and anterior iliac crests and sides of the chest wall are inspected for symmetry. The patient is then turned and viewed from behind, and the shoulder and scapular height, the muscle bulk of the trapezius muscles, and the height of the posterior iliac crests and of the depressions over the sacroiliac joints are checked for symmetry. Trapezius strength is determined by having the patient shrug his or her shoulders, first against gravity and then against resistance, as the examiner presses down on the shoulders. The muscles supplying the scapula are tested by having the patient press his or her outstretched arms against a wall. Winging of the scapula during this maneuver is suggestive of weakness of the serratus anterior muscle. The line of the spinous processes of the vertebrae is observed for straightness, and the position of the head over the trunk is noted. Normally the head is aligned over the midline of the sacrum.


Next, the sternocleidomastoid and paraspinous muscles of the neck are palpated to assess for bulk, tone, tenderness, and spasm, and the spinous processes of the cervical vertebrae are palpated to assess for tenderness and step-off. In the immobilized trauma patient these observations are made largely with the patient supine on a backboard and then log-rolled onto his or her side. Importantly, in checking for neck injury, the cervical spine can be cleared clinically if the patient is awake and alert and has no complaint of neck pain, no evidence of tenderness or paraspinous muscle spasm, and no extremely painful injury elsewhere. If the patient’s level of consciousness is not normal or there is a major distracting injury, the cervical spine cannot be cleared, even if radiographic findings are normal, because spinal cord injury can be present in the absence of bony abnormalities.


Range of neck motion is assessed by having the patient move his or her head. A normal child can touch his or her chin to the chest, extend the neck to look directly above, and bend laterally to 45 degrees. He or she is also capable of symmetrical lateral rotation when turning the head from side to side. Strength is tested by applying pressure to the forehead while the patient flexes his or her neck and to the occiput as the patient extends, and by applying resistance to the opposite side of the head as the patient bends and rotates laterally.



Thoracolumbar Spine

Viewed from the side, the normal child has a lordotic curve in the cervical area with a bony prominence at C7, a mild thoracic kyphosis, a lumbar lordosis, and a sacral kyphosis. Each patient is checked for the presence, absence, or accentuation of these curves. The midline of the back is inspected for evidence of abnormal pigmentation and the presence of hemangiomas, nevi, hairy tufts, dimples, masses, or defects, which may be associated with underlying bony or neural anomalies (see Chapter 15).


Flexion, extension, rotation, and lateral bending of the thoracolumbar spine are primarily motions of the thoracolumbar junction and the lumbar area. Most children can bend forward to touch their toes, bend laterally 20 to 30 degrees (with the pelvis held stable by the examiner’s hands on the iliac crests), and rotate 20 to 30 degrees in either direction.


Examination of the back for spinal deformity is assisted by the use of the Adams forward bend test (Fig. 21-4). For this, the examiner stands behind the patient, who is then asked to bend forward with arms extended and the palms of the hands together. The surface of the back in the lumbar and thoracic regions is examined for asymmetrical elevation of the paravertebral spinous area, thus indicating a structural rotation of the spine and the possibility of scoliosis (Fig. 21-4, B). The examiner should also note any evidence of missing spinous processes (step-off) or their deviation from the midline and palpate the paravertebral muscles for spasm and tenderness. Increased kyphosis, especially in the thoracic region, may be detected when viewing the patient from the side (Fig. 21-4, C), as can lack of reversal of the lumbar lordosis, which may indicate muscle spasm or abnormality of the lumbar spine. Leg length inequality may be evaluated during the upright standing portion of this test (see Lower Extremity Examination, later) and, if present, should be corrected with appropriate lifts under the short side in order not to cause a false forward bend test.



Any examination of the spine must include a neurologic assessment of strength, tone, reflexes, and sensation. The straight leg raising test (Fig. 21-5) can be helpful in demonstrating nerve root pathology in patients with slipped disks, spinal or paraspinal masses, or inflammatory processes. The test is performed with the patient lying supine on the examining table. The limb to be tested is grasped behind the ankle and elevated passively into hip flexion with the knee fully extended. This maneuver stretches the sciatic nerve as it passes behind the hip joint, and if one of its several roots has been irritated by a protruded disk, mass, or inflammatory process, pain will be felt with only 15 to 30 degrees of hip flexion. Normally the straight leg can be brought to 90 degrees of hip flexion without difficulty.




Shoulder

When examining the shoulder, first the position of the upper limbs is observed, at the same time noting whether there is any swelling, asymmetry of height, or visible landmarks and looking for any difference in spontaneous movement. Prominent landmarks that are easily palpable include the acromion process lying laterally and subcutaneously, the clavicle, the spine of the scapula, the coracoid process, and the bicipital groove. Any displacement or tenderness of these structures should be noted. Swelling of the glenohumeral joint capsule and atrophy of the shoulder muscles are best appreciated by viewing from above with the patient seated and by comparison with the normal side.


Assessing range of motion is important because many shoulder problems are manifested by a loss of normal motion. The shoulder is a ball-and-socket joint with six components of movement. Abduction, a function of the deltoid muscle, is tested by having the patient raise the extended, supinated arm up so that the hand is directly above the shoulder (180-degree abduction). To test adduction, the patient is asked to flex his or her shoulder to 20 to 30 degrees and then draw the upper arm diagonally across his or her body (75 degrees is normal). Flexion is assessed by having him or her raise the extended pronated arm up and forward until it is parallel to the floor; extension is tested by having him or her return the arm to the neutral position and then lift the arm up and backward (45 to 60 degrees is normal). To check rotation, the upper arm is held to the side with the elbow flexed to 90 degrees and the child is asked to turn the forearm toward the body (medial) and then out to the side (lateral) (60 to 90 degrees is normal).




Wrist and Hand

During examination of the wrist and hand, one should observe skin color, check capillary refill, and palpate the radial and ulnar pulses to assess circulation. Any swelling or edema should be noted, as well as any abnormal posture or position. The presence of intraarticular fluid in the wrist is manifested by swelling and tenderness, especially evident dorsally, and by restriction of wrist motion. Wrist motion has four components: flexion with the hand held down (normally 70 to 80 degrees); extension with the hand held up (normally 70 degrees); and ulnar and radial deviation (normally 25 degrees and 15 to 20 degrees, respectively).


Examination of hand function can be particularly challenging in young children because of lack of cooperation and developmental limitations. Observation of the position at rest (normally a loose fist with all the fingers pointing in the same direction and with the same degree of flexion) and of use during play is often helpful. Having the parent perform various hand and finger motions while trying to get the child to imitate these can be helpful in some cases. Handing the child a small object such as a key or a thin piece of paper such as a dollar bill may suffice for assessing opposition of thumb to fingers, which in the older child is tested by having him or her touch the tip of the thumb to the tip of the little finger. Normal ranges of motion in the hand are 90 degrees of flexion and 45 degrees of extension for the metacarpophalangeal joints, full extension and 100 degrees of flexion for the proximal interphalangeal (PIP) joints, and full extension and 90 degrees of flexion for the distal interphalangeal joints.


Because the bones of the hand are subcutaneous, displaced fractures and dislocations are readily evident on inspection. Laceration or rupture of the tendons is common because of their superficial location. Those involving flexor tendons result in extensor tendon overpull (Fig. 21-7), with the affected digit lying in greater extension than its neighbors at rest. Conversely, extensor tendon lacerations result in flexor muscle overpull, with the opposite result.



Functional testing of the tendons and intrinsic muscles of the hand is generally possible in older children. They can be asked to extend the fingers at the metacarpophalangeal joints and each interphalangeal joint. Function of the flexor digitorum profundus muscle is tested by holding the PIP joint extended while the patient flexes the tip of the finger. To test the superficialis flexor tendon, adjacent distal interphalangeal joints are held in extension and the patient is asked to flex the finger being tested at the PIP joint. The intrinsic muscles of the hand are evaluated by having the child adduct and abduct the fingers toward and away from the middle finger. Sensation is best tested using two-point discrimination and pinprick in older children and by touch in very young children.


Muscle strength in the upper extremity is largely tested during assessment of range of motion of the joints, with and without resistance. Signs of neural dysfunction with injury of the upper extremity are listed in Table 21-2.


Table 21-2 Signs of Neural Dysfunction with Injury of the Upper Extremity




































Nerve Sign
Radial ↓ Strength of wrist and finger extensors
  ↓ Sensation in web space between thumb and index finger, dorsum of hand to proximal interphalangeal joints, and radial aspect of ring finger
Ulnar ↓ Strength of wrist flexion and adduction
  ↓ Strength of finger spread
  ↓ Sensation over ulnar aspect of palm and dorsum of hand, little finger, and ulnar aspect of ring finger
Median ↓ Strength of wrist flexion and abduction
  ↓ Strength of flexion of proximal interphalangeal joints
  ↓ Strength of opposition of thumb to base of little finger
  ↓ Sensation over radial aspect of palm, thumb, index, and long fingers
Anterior interosseous ↓ Strength of flexion of the distal interphalangeal joints of the index finger and thumb


Lower Extremity Examination



Hip

Examination of the hip begins by assessing gait (see later discussion) and stance, checking the latter to see if the anterior superior and posterior superior iliac spines and the greater trochanters are level. If not, a leg-length discrepancy should be suspected and leg length measured. Total length is measured from the bottom of the anterior superior iliac spine to the medial malleolus of the ankle with the patient supine. If inequality is found, the knees are flexed to 90 degrees with the feet flat on the examination table. If, as the examiner looks from the foot of the examination table, one knee appears higher than the other, the tibias are unequal in length; if one knee is anterior to the other when viewed from the side, the discrepancy involves the femurs. If total leg lengths are equal, the inequality apparent when the patient is standing may be due to pelvic obliquity or flexion contracture of the hip. The latter may also be associated with a compensatory accentuation of lumbar lordosis.


The thighs are checked next for symmetry and signs of atrophy. If atrophy is found, circumference should be measured and compared at a fixed point below the greater trochanters.


Because the hip lies deep and is surrounded by muscles, direct inspection is impossible and palpation is of limited value (although the femoral triangle, greater trochanter, and posterior aspect should be palpated to check for tenderness). As a result, assessment of the position of comfort (abduction and external rotation are seen with effusion, hemarthrosis, and fracture; see Figs. 21-15, C and 21-91, B), weight bearing, range of motion, and pain on motion are particularly important (for hip examination in the neonate, see Developmental Dislocation of the Hip, later).


In evaluating range of motion of the hip, care must be taken to distinguish true hip motion from that occurring in combination with pelvic rotation or trunk flexion. The range of hip flexion is normally about 120 degrees. It is tested with the child lying supine. The hip to be tested is passively flexed while the contralateral hip and pelvis are observed or stabilized by one hand. The limit of flexion is reached when movement of the contralateral pelvis is noted. Alternatively, both hips can be flexed simultaneously to stabilize the pelvis and eliminate truncal flexion. The Thomas test is performed by flexing both hips so that the thighs touch the abdomen. Then one is held in place, thereby eliminating lumbar lordosis and movement of the lumbosacral joint, and the patient is asked to extend the hip to be tested. Normally he or she should be able to extend the hip to 0 degrees of flexion (Fig. 21-8, A). Failure to do this indicates the presence of a hip flexion contracture, which is a positive result on the Thomas test (Fig. 21-8, B). Next, the knee and thigh are held with the hip and knee flexed to 90 degrees and internal and external rotation are tested and recorded in degrees. Abduction and adduction are also checked with the hip flexed to 90 degrees. While the examiner places the thumb and index finger of one hand over the patient’s pelvis, attempting to span the distance between the anterior superior iliac spines, the hip to be tested is abducted and then adducted. The limit is determined by the point at which the pelvis begins to move (normally 45 degrees of abduction and 30 degrees of adduction). Extension is tested with the patient prone by having him or her lift the leg up from the table (normal, 20 to 30 degrees). Internal and external rotation are also tested with the patient prone and the hip and leg in extension.



When hip abductor weakness is suspected on the basis of the finding of a gait abnormality, the Trendelenburg test (Fig. 21-9) is performed. This involves having the child stand and asking him or her to lift one leg up. Normally the pelvis should rise slightly on the side of the leg that is lifted. If instead it drops, abductor weakness is present on the opposite side, and the Trendelenburg test is positive.




Knee

Importantly, knee pain is a common reason for seeking orthopedic care and it is often referred from the hip; thus any patient presenting with knee pain should always be examined for possible limitation of hip motion or pain on motion of the hip.


The knee examination begins with the examiner viewing the joint from the front, side, and back, looking for differences in contour, swelling or masses, and changes in overlying skin. From the front, the knee is inspected for valgus (lower leg points away from the midline) or varus (lower leg deviates toward the midline) deformity and for evidence of effusion, manifested by obliteration of the normal depressions around the patella or by generalized swelling. In viewing the knee from its lateral aspect, the examiner looks for incomplete extension resulting from flexion contracture or excess hyperextension (recurvatum deformity), as well as for symmetry of the tibial tuberosities. From the rear, the popliteal fossae are checked for symmetry and evidence of swelling. The thighs are also observed for comparative size and contour.


The knees are palpated to assess warmth and check for tenderness along the medial and lateral joint lines, the medial and collateral ligaments, the patella and its supporting ligaments, the femoral and tibial condyles, and the tibial tubercles. Palpation is easier with the knee flexed because the skeletal landmarks are more readily seen and felt, and the muscles, tendons, and ligaments are relaxed in this position.


When there is evidence of a marked effusion, landmarks are obscured and the patella is readily ballotable. This is seen with intraarticular hemorrhage, arthritis, and synovitis, and range of motion is usually significantly limited. If landmarks are only mildly obscured (suggestive of a mild joint effusion or fluid collection in the bursae), pressure should be applied over the suprapatellar pouch with the thumb and index finger of one hand, milking down any fluid present while simultaneously pushing the patella up toward the femoral condyles with the other hand (Fig. 21-10). If fluid is present, the patella is ballotable and a palpable click is noted as the patella strikes the front of the femur.



The knee is primarily a hinge joint and is normally capable of 130 to 140 degrees of flexion and 5 degrees of hyperextension. However, it can also rotate approximately 10 degrees internally and externally, and this involves rotation of the tibia on the femur. Flexion is tested with the patient either sitting or lying prone. To test extension, the examiner can have the patient either sit and try to straighten the leg to 0 degrees of flexion or try to lift the straightened leg from the examination table while lying supine. Rotation is assessed by turning the foot medially and then laterally with the knee flexed.


With the knees flexed to 80 to 90 degrees, the patellas should face forward when viewed from the front and be located squarely at the ends of the femurs when seen from the side. The apprehension test (Fig. 21-11) is performed to check for a subluxating or dislocating patella. With the patient sitting, the examiner supports the lower leg and holds the knee flexed to 30 degrees. The patella is then gently pushed laterally. Any abnormal amount of lateral displacement, pain, or apprehension in response to this maneuver indicates a positive test.



Ligamentous stability of the knee should be assessed in the mediolateral and anteroposterior planes. In patients with acute injuries, especially those involving significant pain and swelling, this should be deferred until radiographs have been obtained to check for associated fractures.


The abduction/adduction stress test is used to determine the degree of stability of the medial and lateral collateral ligaments. With the supine patient’s thigh moved to the side of the examination table and the knee flexed to 30 degrees, the examiner holds the distal thigh in one hand while grasping the inside of the lower leg with the other. To test the medial collaterals, the examiner applies valgus stress by pressing medially against the distal thigh with the upper hand while gently abducting the lower leg. To check the lateral collaterals, the examiner applies varus stress by pressing laterally on the inside of the distal thigh while gently adducting the lower leg. Normally the joint line should open no more than 1 cm on either side.


Anteroposterior ligamentous stability is provided by the anterior and posterior cruciate ligaments of the knee. They are tested by the anterior and posterior drawer and Lachman tests. The former are performed with the patient supine; the hip and knee flexed to 45 and 90 degrees, respectively; and the foot planted on the examining table, stabilized by the examiner’s thigh or buttock. The examiner then grasps the proximal tibia with his or her fingers behind the knee and the thumbs over the anterior joint line and gently pulls and pushes (Fig. 21-12). In a positive anterior drawer test, the tibia moves forward more than 0.5 to 1 cm, indicating instability of the anterior cruciate ligament. Movement backward more than 0.5 to 1 cm indicates instability of the posterior cruciate ligament. In the Lachman test (Fig. 21-13) for anterior cruciate tears, the knee is flexed to 15 degrees. The examiner grasps the distal femur with one hand and the proximal tibia with the other. The thumb of the lower hand is placed on the joint line, and the femur is pushed backward as the tibia is pulled forward. Abnormal anterior displacement of the tibia on the femur can be seen and felt if instability is present. The amount of excursion is estimated in millimeters, and the end point is recorded as soft or firm.





Ankle

Examination of the ankle begins with inspection for evidence of deformity, swelling, change in color of overlying skin, and abnormal position (especially with weight bearing). Palpation is performed to detect warmth and to localize tenderness. In the neutral position the long axis of the foot should be at 90 degrees to the long axis of the tibia. Normally a child can dorsiflex 20 degrees and plantar flex 30 to 50 degrees from the neutral position, as well as invert and evert approximately 5 degrees. Dorsiflexion and plantar flexion can be checked by observing passive and active motion (with and without resistance) but are perhaps most easily tested by having the ambulating child walk on his or her heels and toes, respectively. Similarly, inversion is tested by having him or her walk on the outside of the feet and eversion by having him or her walk on the medial sides.


Tests for ligamentous instability can be important after severe ankle sprains. The anterior drawer test is used to assess the stability of the anterior talofibular ligament. With the patient’s legs dangling over the side of the examination table and the foot in a few degrees of plantar flexion, the examiner grasps the anterior aspect of the distal tibia with one hand while holding the calcaneus cupped in the palm of the other. The calcaneus is then drawn anteriorly while the tibia is pushed posteriorly. Normally there should be no movement, but with instability of the anterior talofibular ligament, the talus slides anteriorly. Lateral instability is seen only with major tears of the anterior talofibular and calcaneofibular ligaments, occasionally accompanied by tears of the posterior talofibular ligament, and is tested by inverting the calcaneus with one hand while grasping the distal tibia with the other. When instability is present, the talus gaps and rocks in the ankle mortise. Medial instability is exceptionally rare because of the strength of the fan-shaped deltoid ligament. To test for medial instability, the tibia and calcaneus are held in the same manner as they are in testing lateral instability, but the foot is everted instead. Gross gaping of the ankle mortise is felt when there is a major tear.



Gait and Gait Disturbances


Between the onset of walking and 3 years of age, children tend to have a wide-based gait and toddlers often hold their arms out to the side to assist balance. By 3 years of age, children achieve a normal smooth and rhythmic heel-to-toe gait, consisting of two main phases: stance and swing. The stance phase begins when the heel strikes the ground, bears all the weight, and progresses to foot flat, midstance, and push-off as weight is transferred from the heel to the metatarsal heads. The swing phase starts with acceleration after push-off and progresses through midswing to deceleration just before heel strike. During the swing phase, as the leg moves forward, so does the opposite arm. Because stance occupies 60% of the time and weight is borne in this phase, most gait disorders are more evident during the stance phase than during the swing phase. Normally the distance between the two heels (width of the base) is between 5 and 10 cm, the pelvis and trunk shift laterally about 2.5 cm from stance to stance, the center of gravity rises and falls no more than 5 cm, and the pelvis rotates forward about 40 degrees during swing.


Gait is best observed by having the patient walk back and forth in a hall or in a room with a mirror at one end. As the patient walks, the examiner focuses first on overall movement and then on the motion of the pelvis, hips, thighs, knees, lower legs, ankles, and feet in succession, both coming and going. In doing so, he or she looks for the pattern of heel-to-toe motion, for shortening of the stance phase, for evidence of limitation of joint motion or weakness, and for positional changes of the extremities. Checking the patient’s shoes for signs of abnormal wear is also helpful.


Most acute and many chronic disturbances of gait in childhood are caused by pain. Others stem from weakness or spasticity caused by neurologic or muscular disorders, from leg length inequality, or from deformity. Important historical points are the time of onset of the abnormal gait and the circumstances surrounding it; the duration; whether the abnormal gait is constant or intermittent and, if intermittent, the time of day it is most apparent (a.m., juvenile rheumatoid arthritis; p.m., neuromuscular disorders—symptoms becoming more apparent with fatigue); and its relation to activity or exercise including its effect on running or climbing stairs. The examiner should note any associated pain and its location, bearing in mind referral patterns (low back to buttocks and lateral thigh; hip to groin, medial thigh, knee, and sometimes buttock) and attempting to determine whether the pain is constant (suggestive of tumor or infection) or intermittent.




Gait Disturbances Resulting from Weakness or Spasticity


Patients with weakness of the hip abductors (gluteus medius muscle) have a Trendelenburg gait. Because they are unable to maintain a level pelvis and linear progression of their center of gravity, their pelvis tilts toward the unsupported side and their shoulder lurches toward the weak side during stance phase to maintain their center of gravity over the foot. Patients with weakness of the gluteus maximus (seen most commonly in children with Duchenne muscular dystrophy) have to hyperextend their trunk and pelvis to maintain their center of gravity posterior to the hip joint (see Chapter 15). Proximal muscle weakness may also be demonstrated by observing a child getting up from the floor unassisted. A Gower sign indicates weak hip extensors and abductors, necessitating that the patient use his arms to assist in standing by placing his hands on his anterior thighs and pushing up, progressively moving his hands upward along the thighs until erect posture is achieved (see Chapter 15). Children with weakness of the quadriceps femoris muscle may have a relatively normal gait on level ground but difficulty climbing stairs. Weakness of the dorsiflexors of the foot results in foot drop and a steppage gait. Because the foot hangs down during the swing phase, the patient must lift the knee higher than usual to help the foot clear the floor and the forefoot tends to slap the floor on impact because smooth deceleration of the foot cannot be controlled. When the plantar flexors are weak, the patient is unable to push off at the end of the stance phase and so the heel and forefoot come off the floor at the same time.


An equine gait, characterized by toe-walking or a toe-to-heel sequence during the stance phase, is seen in children with heel cord contracture and limited dorsiflexion. It is usually indicative of an underlying neurologic problem with spasticity. Patients with spastic cerebral palsy who are able to ambulate often manifest a stiff-legged scissors gait, in which one foot crosses over the other during the swing phase. Vestibular or cerebellar dysfunction or generalized weakness tends to result in a wide-based ataxic gait because of abnormal balance. Absence of the normal arm swing with walking is seen in patients with paresis or cerebellar disease.



Intoeing and Out-toeing

The angular difference between the long axis of the foot and the forward line of progression during walking is called the foot progression angle. A minus value is assigned to intoeing, a plus value to out-toeing. The normal range varies from 5 to 10 degrees to 10 to 20 degrees, respectively. The remaining rotational profile of the lower extremities can be examined with the patient in the prone position (Fig. 21-14). The foot axis can be determined by a line marked from the middle of the heel on the plantar surface to the lateral side of the second toe (Fig. 21-14, A). The hip excursion is the difference between the angular measure of the maximal prone internal rotation (Fig. 21-14, B) and that for external rotation (Fig. 21-14, C), and in the young child is usually negative, representing more internal rotation than external rotation. In the adolescent and adult, usually there is more external rotation, or a positive hip excursion angle. Finally, the axis of the tibia and fibula can be determined by looking down the lower extremity in the prone knee-flexed position and comparing the axis of the plane of motion of the knee (Fig. 21-14, D) with the transmalleolar axis (Fig. 21-14, E) estimated by palpating the malleoli. The normal axis is 15 to 25 degrees externally rotated.



Femoral anteversion, internal tibial torsion, and metatarsus adductus are common causes of excessive intoeing, or pigeon toe, and femoral eversion and external tibial torsion are common causes of out-toeing, or slew foot (see Disorders of the Lower Extremity, later).



Musculoskeletal Trauma


The normal impulsiveness and inquisitiveness of children combined with their lack of caution and love of energetic activities place them at a relatively high risk for accidental injury. The incidence of trauma is further increased by the prevalence of child abuse (see Chapter 6). In fact, beyond infancy, trauma is the leading cause of death in children and adolescents and is a source of significant morbidity. Musculoskeletal injuries are common, whether seen in isolation or as part of multisystem trauma. Although the management of life-threatening injuries to the airway, circulation, and central nervous system (CNS) must take precedence over treatment of accompanying musculoskeletal injuries in cases of multiple trauma, it must be kept in mind that fractures can result in significant blood loss. This is particularly true of pelvic and femoral fractures. Furthermore, prompt attention must be given to assessment of the status of neurovascular structures distal to obvious fractures because failure to recognize compromise may result in permanent loss of function. Finally, traumatic hip dislocations must be reduced within 6 to 12 hours if the risk of aseptic necrosis and long-term morbidity is to be minimized.



Fractures



Diagnosis


One of the many variables that complicate the diagnosis of the skeletally injured child is that the child, already in pain, is frightened by his or her recent experience and by the strangeness of the hospital or emergency department setting. Many children are too young to give a firsthand history, and the cooperation of toddlers is often limited. The parents are likely to be anxious as well. A calm, empathetic manner is necessary to allay their fears. Taking a thorough history before making any attempt to perform a physical assessment helps the examiner establish rapport with the patient and the family. This should include questions concerning the type and direction of the injuring force, the position of the involved extremity at the time of the accident, and the events immediately following the injury such as measures taken at the scene of the accident. The presence of underlying disorders and the possibility of contamination of an open wound should be determined as well. Physicians also should be alert to signs suggestive of inflicted injury or child abuse. These include a history in which the mechanism of injury does not fit the type and/or severity of the fracture found, an unusual delay in presentation, and/or radiographic evidence of old healing fractures for which no medical attention was ever sought.


In cases of suspected fracture, splinting, elevation, and topical application of ice may help reduce discomfort and local swelling. Splinting is particularly important for displaced and unstable fractures because it prevents further soft tissue injuries and reduces the risk of fat embolization. When pain is moderate to severe and there are no cardiovascular or CNS contraindications, analgesia should be administered promptly. Contrary to the opinion of many physicians, this does not obscure physical findings. Tenderness is not reduced significantly, swelling remains, and patient cooperation during the examination may be considerably greater.


Before beginning the physical examination, it is wise for the examiner to talk with the child to further gain his or her trust. Older infants and toddlers are often more comfortable when allowed to sit on a parent’s lap, and use of puppets or toys can reduce fear and help gain their cooperation. Because comparison of paired extremities is an integral part of orthopedic assessment, it is best to begin by examining the uninjured side and it is wise to defer palpation of the most likely site of the injury on the affected side until last. If young children are highly anxious, it can be useful to instruct the parent in how to perform passive range of motion and palpation.


The first step in the physical examination is visual inspection of the injured area. The gross position of the extremity should be noted, and attention given to the presence or absence of deformity, distortion or abnormal angulation, and longitudinal shortening (Fig. 21-15). The overlying skin and soft tissues are examined for evidence of swelling, ecchymoses, abrasions, punctures, and lacerations. Comparison with the opposite extremity and measurement of circumference can be helpful when findings are subtle.



The location of open wounds is important in ascertaining whether an underlying fracture is open or closed and in assessing the risk of joint penetration. Small puncture wounds or lacerations overlying bony structures from which a bloody, fatty exudate is oozing usually reflect communication with the medullary cavity of a fractured bone. Similarly, punctures or tears over joints that weep serous or serosanguineous fluid, especially when drainage is increased on moving the joint, must be assumed to communicate with the joint capsule (Fig. 21-16, A). In patients with penetrating joint injuries, radiographs may demonstrate air in the joint, but absence of this does not rule out capsular penetration (Fig. 21-16, B). Probing of open wounds that are highly likely to communicate with a fracture or joint is contraindicated. The wound should be cleaned and covered with a sterile dressing until its extent can be determined under sterile conditions in the operating room.



After inspection of the most obviously injured area, palpation and assessment of active and passive motion can be performed. It is crucial to remember that in examining an injured limb the entire extremity must be evaluated in order to detect less obvious associated injuries. Localized swelling and tenderness on palpation are significant findings and should alert the examiner to the high likelihood of an underlying fracture. Pain on motion and limitation of motion signal the need for careful scrutiny as well. Assessment of motion involves observation of spontaneous movement, attempts to get the patient to voluntarily move the involved part through its expected range, and passive movement. Particular attention should be paid to the adjacent proximal and distal joints to avoid missing associated injuries. It can be difficult, however, to determine whether motion is limited because of pain, an associated injury, or fear and lack of cooperation.


Clinical findings vary depending on the nature of the fracture. Undisplaced growth plate fractures typically present with mild, localized swelling and point tenderness at the level of the epiphysis (Fig. 21-17). Because ligamentous injury is relatively uncommon in a child, the finding of point tenderness should suffice to prompt treating the injury as a fracture until proven otherwise. Often initial radiographs appear normal and the fracture is confirmed only on follow-up when repeat radiographs disclose evidence of healing. Swelling is typically mild and occasionally imperceptible in cases of torus or buckle fractures and of undisplaced transverse and spiral fractures. Careful palpation should disclose focal tenderness, however. Usually, the patient also experiences some degree of discomfort on motion in some planes or on weight bearing, but it must be remembered that limitation of movement or function can be minimal in patients with such incomplete fractures. In contrast, fractures that completely disrupt the bone and displaced fractures are accompanied by more prominent swelling; more diffuse tenderness; and severe pain, which is markedly increased on motion (Fig. 21-18; see also Fig. 21-15, A and B). Crepitus may also be evident on gentle palpation. In examining children with these findings, manipulation must be kept to a minimum to prevent further injury.




Assessment of neurovascular function distal to the injury is essential in evaluating any child with a potential fracture. This includes checking the integrity of pulses and speed of capillary refill, as well as testing sensory and motor function. Strength and sensation should be compared with those of the contralateral extremity. Assessment of two-point discrimination is probably the best test of sensory function. Evidence of neurovascular compromise necessitates urgent, often operative, orthopedic treatment. In addition, this assessment is crucial before and after reduction of displaced fractures to determine whether the procedure itself has impaired function in any way. Persistence of intense pain after fracture reduction should provoke suspicion of ischemia.


Supracondylar fractures of the humerus, fractures of the distal femoral shaft and proximal tibia, fracture–dislocations of the elbow and knee, and severely displaced ankle fractures are particularly likely to be associated with neurovascular injury.


Even relatively minor fractures of the tibia, forearm bones, metatarsals, and femur can result in compartment syndrome, in which bleeding and edema collection within a closed fascial compartment produce increased pressure that causes neurovascular compromise and muscle ischemia. This should be strongly suspected in patients who complain of intense pain that is aggravated by passive stretching of the muscles. On palpation the area is noted to be swollen and tense, at times even hard. The patient may complain of paresthesias and show pallor and decreased pulses. However, it is important also to be aware of the fact that vascular compromise can be present in a patient who has normal distal pulses and good peripheral perfusion (see Compartment Syndromes, later).


In all cases of suspected extremity fractures the injured part should be properly splinted and elevated, an ice pack applied, and analgesia administered while the patient awaits transport to the radiography suite. However, to obtain high-quality radiographs, obstructing splints must be removed temporarily. This presents no major problem in patients with partial or nondisplaced fractures but can create difficulties in patients with severe displaced fractures. To ensure that manipulation is minimal in these patients, splint removal, positioning for radiographs, and splint reapplication should be supervised by a physician and not done merely at the discretion of the x-ray technician.


At a minimum, two radiographs taken at 90-degree angles are obtained, anteroposterior (AP) and lateral views being the most common. Oblique views are helpful in fully disclosing the nature and extent of many fracture patterns, especially when the injury involves the ankle, elbow, hand, or foot. They can also prove useful in detecting subtle spiral fractures and in cases in which the AP and lateral views are normal, yet a fracture is strongly suspected. Radiographs should include the joints immediately proximal and distal to a fractured long bone, because there may be associated bony or soft tissue injuries in these areas as well. Such associated injuries easily can be missed on clinical examination when assessment of motion is limited by pain or when patient cooperation is limited. It is necessary to obtain comparison views of the opposite side, especially when evaluating patients with suspected physeal injuries who may have very subtle radiographic abnormalities. These views can also prove invaluable in detecting cortical disruptions. In some cases of displaced or angulated fractures, potentially complex intraarticular fractures, and vertebral and pelvic fractures, a computed tomography (CT) scan can be useful. A bone scan may be necessary to detect subtle stress fractures.


Particular care should be taken in interpreting pediatric radiographs because of the high incidence of subtle or even normal findings in patients with fractures. If the clinical picture strongly suggests a fracture, appropriate treatment should be initiated, even if the radiograph appears normal. Reassessment in 1 to 2 weeks can then clarify the exact nature of the injury.



Fracture Patterns


Fractures should be described in terms of anatomic location, direction of the fracture line, type of fracture, and degree of angulation and of displacement. When the growth plate is involved, use of the Salter-Harris classification system is recommended.


Any specific mechanism of injury results in a readily definable pattern of force application, which tends to produce a typical fracture pattern. Because of this, it is often possible to infer the likely mechanism of injury once the fracture pattern is documented radiographically. If the vector of the direct force is perpendicular to the bone, a transverse fracture is most likely to result, whereas direct force applied at any angle to the bone produces an oblique fracture pattern. Examples of situations resulting in transverse and short oblique fractures include falls in which an extremity strikes the edge of a table, counter, or chair; direct blows with an object such as a stick; and karate chops. These fractures are commonly seen as a result of accidents or fights and in the battered child syndrome. Comminuted fractures generally result from high-velocity, direct forces such as those characteristic of vehicular accidents, falls from heights, or gunshot wounds. Impacted fractures are produced by forces oriented in a direction parallel to the long axis of the bone. Application of indirect force commonly results in spiral, greenstick, or torus fractures in children.


A common example of a nondisplaced spiral fracture is the toddler’s fracture (see Fig. 21-43), which results from a fall with a twist. Typically, the child was either running, turned, and then fell; jumped and fell with a twist; or got his or her foot caught and fell while twisting to extricate himself or herself. If a child’s arm or leg is forcibly pulled and twisted, a similar fracture pattern may be seen. Greenstick and torus fractures of the radius or ulna are incurred usually when the child falls on an outstretched arm with the wrist dorsiflexed. Vigorous repetitive shaking while holding a child by the hands, feet, or chest results in small metaphyseal chip or bucket-handle fractures, a major feature of the shaken-baby syndrome (see Chapter 6). Table 21-3 summarizes the major features of these various fracture patterns, which are illustrated in Figures 21-19 through 21-27.


Table 21-3 Patterns of Fractures











































Fracture Pattern Major Feature Radiographic Appearance
Longitudinal Fracture line is parallel to the axis of a long bone Fig. 21-19
Transverse Fracture line is perpendicular to the axis of a long bone Fig. 21-20; and see Fig. 21-28
Oblique Fracture line is at an angle relative to the axis of a bone Fig. 21-21
Spiral Fracture line takes a curvilinear course around the axis of a bone Fig. 21-22; and see Fig. 21-43
Impacted Bone ends are crushed together, producing an indistinct fracture line Fig. 21-23
Comminuted Fracturing forces produce more than two separate fragments Fig. 21-24
Bowing Bone bends to the point of plastic deformation without fracturing Fig. 21-25
Greenstick Fracture is complete except for a portion of the cortex on the compression side of the fracture, which is only plastically deformed Fig. 21-26; and see Fig. 21-25, B
Torus Bone buckles and bends rather than breaks Fig. 21-27; and see Fig. 21-29










The anatomic location of the fracture line simply refers to that portion of the bone to which the injury force was applied. Table 21-4 presents types of fractures classified by anatomic location. These fractures are illustrated in Figures 21-28 through 21-36. There is some degree of overlap in this method of categorization, however.


Table 21-4 Classification of Fractures by Anatomic Location















































Type Site Radiographic Appearance
Diaphyseal Fracture involves the central shaft of a long bone Fig. 21-28; and see Figs. 21-21, 21-22, and 21-25
Metaphyseal Fracture involves the widened end of a long bone Fig. 21-29; and see Fig. 21-26 and Chapter 6
Epiphyseal Fracture involves the chondro-osseous end of a long bone. Such fractures can also be classified as Salter-Harris fractures Fig. 21-30
Articular Fracture involves the cartilaginous joint surface Fig. 21-31; see also Figs. 21-40 and 21-41
Intercondylar Fracture is located between the condyles of a joint. This is one variant of articular fracture and could also be subclassified as a Salter-Harris fracture Fig. 21-31, A
Physeal Fracture involves the growth center of long bone. These are subclassified according to the Salter-Harris system Fig. 21-32
Condylar Fracture traverses the condyle of a joint Fig. 21-33
Supracondylar Fracture line is located just proximal to the condyles of a joint Fig. 21-34
Epicondylar Fracture involves an area juxtaposed to the condylar surface of a joint Fig. 21-35
Subcapital Fracture is located just below the epiphyseal head of certain bones Fig. 21-36

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Jul 11, 2016 | Posted by in PEDIATRICS | Comments Off on Orthopedics
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