May 2017

Growth-plate injuries: a diagnostic challenge

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Physeal trauma can be hard to spot, and mismanagement can disturb normal development and lead to lower extremity issues,  such as limb-length discrepancy and  abnormal biomechanics. A thorough clinical exam, including details of the moment of injury, is often key to accurate diagnosis.

By Shalmali Pal

In pediatric patients, two things have a high degree of certainty: They will grow, and they will injure themselves. These two inevitabilities often overlap in the form of physeal, or growth-plate, injuries.  Involvement in sports, or other organized physical activities, may be a primary reason for physeal injuries—it’s estimated that 25% of all childhood injuries occur during sports, and young athletes (aged 5-18 years) account for 40% all sports-related injuries that turn up at the emergency department (ED).1

And that’s where physeal injuries can get complicated, as recognizing and managing them may not be as forthright as in adult patients, explained Nailah Coleman, MD, a pediatric sports medicine specialist at the Children’s National Health System in Washington, DC, and a spokesperson for the American College of Sports Medicine.

“If the child presents to an adult-intensive ED, those physicians may not be as knowledgeable about physeal injuries, especially if they don’t see [the injury] that day on an x-ray,” she said. “They may suspect that it’s a fracture, but not treat it as one initially. The child may return home thinking that it’s just a sprain, but then they have continued pain, possibly for months.”

The growth plate is the weakest link in immature skeletons and when injured, can exhibit complete growth arrest, be impaired partially, or develop normally.

“Sometimes, it’s an issue with the family,” added Coleman, who also serves on the leadership board of the National Youth Sports Health & Safety Institute. “They come to the ED right after the injury occurs, but they want to believe that it’s just a sprain because they don’t want to deal with a broken bone and the longer recovery time that will take.”

Whatever the reason, missing or misdiagnosing physeal injuries can have long-term effects for a child’s growth and development. Mismanaged physeal injuries can lead to long-term complications, including growth disturbance and abnormalities such as limb-length discrepancy, angular deformity, and altered joint mechanics.

Physeal vs apophyseal

First, some basic definitions: The physis is located at the distal portion of long bones. It’s composed of cartilage that allows the bones to expand, lengthen, and ultimately ossify when skeletal maturity is reached.

“Physeal centers close from distal to proximal, with the last being the clavicle, which may remain open into a person’s early twenties. Prior to closure, while in the cartilaginous state, the physis is prone to failure with abnormal traumatic or chronic stress. The growth plate is the weakest link in the immature skeleton and when injured, can exhibit complete growth arrest, be impaired partially, or develop normally. The potential for growth disturbance makes identifying and appropriately managing a physeal injury a high priority,” wrote Donna Merkel, PT, and Joseph T. Molony Jr, PT, in a review article.1

The Salter-Harris system classifies five types of fractures localized to the growth plate of a bone. (Image courtesy of the American Academy of Orthopaedic Surgeons.)

Although the term “growth-plate injury” is used in a global sense, there are two types of these injuries. True physeal injuries are fractures localized to the growth plate of a bone. These injuries are further classified by the Salter-Harris classification system. There are five types of Salter-Harris fractures:2

Type I: through the physis, or growth plate

Type II: involve the physis and metaphysis

Type III: involve the physis and epiphysis

Type IV: involve the physis, metaphysis, and the epiphysis

Type V: compression injury of the physis

Then there are apophyseal injuries that occur at a secondary ossification center and the site where tendons attach to bone. In children, muscles and tendons tend to grow slower than bone, creating tension at the apophysis. As a result, force or trauma can lead to an avulsion of the apophysis from the attachment site to the bone.

The most common areas for apophyseal injuries are the hip and pelvis, as the hamstring muscles of the posterior thigh attach to the ischial tuberosities, and the rectus femoris muscle attaches to the anterior inferior iliac spine.

Other areas of apophyseal avulsion fractures are the anterior superior iliac spine, greater and lesser trochanter of the femur, the tibial tubercle, and the base of the fifth metatarsal in the foot.2 For instance, tuberosity avulsion fractures can cause pain, tenderness, local bruising, and swelling at the base of the fifth metatarsal. Although nondisplaced tuberosity fractures are usually treated conservatively—a posterior splint followed by a molded, nonweight­bearing, short leg cast—orthopedic referral will be necessary for fractures that are comminuted or displaced; fractures that involve more than 30% of the cubometatarsal articulation surface; and fractures with delayed union.3,4 Although most fractures of the proximal portion of the fifth metatarsal do respond well to appropriate management, long-term complications of these untreated fractures include delayed union, muscle atrophy, and chronic pain.3,4

True physeal injuries are more likely to result from trauma, but they can happen either through contact or noncontact in a sport, explained Molony, a pediatric rehabilitation specialist at the Hospital for Special Surgery (HSS) in New York, NY.

An example of a traumatic injury would be “when a player goes to cut, twists their ankle, and sustains a Salter Harris type I of the distal fibula,” said Molony, the coordinator for the HSS Young Athlete Program. Alternatively, a player could take a hit to the knee and the fracture can occur. Pain and discomfort from a physeal injury will most likely be felt immediately.

On the other hand, an apophyseal “nontraumatic [injury] would be from continuous, low-load accumulation over time that is generally going to lead to a Salter I, as well, but it’s going to gap the physis/apophysis a bit, or create irritation across it,” Molony explained, adding that a Salter II and above in the overuse category is not likely.

That irritation may take some time to build up and cause problems for the player. Molony gave the example of a midfielder in soccer, a position that involves a great deal of running relative to other positions on the pitch. “So, day in and day out, that load can then start to generate a little bit of discomfort in and around the physis or apophysis. But they may keep playing through it, which can lead to the overuse injury.”

Sports-specific issues

Coleman said she generally sees more apophyseal injuries versus physeal injuries, especially in kids who specialize in a single sport, as their training is geared toward the same mechanics year-round.

“They often overuse [growth] areas that shouldn’t have so much continuous stress on them at that time,” she explained. “The apophyseal injuries tend to be overuse injuries because they are repeating the same actions in a single sport.” Indeed, the American Academy of Pediatric Medicine recommends against sports specialization for young athletes, citing potential adverse health effects, including musculoskeletal ones.5 (See “Early athletic specialization: Misconceptions and hazards,” February 2017, page 15.)

In terms of which sports carry a higher risk for either type of lower extremity growth-plate injury, those that involve kicking top the list—soccer, martial arts, football, even dancing, according to Jennifer M. Weiss, MD, an orthopedic surgeon at Kaiser Permanente in Los Angeles, and a spokesperson for the American Academy of Orthopaedic Surgeons.

Sports that require pivoting, jumping, and running also pose a higher risk, particularly for acute physeal injuries, Coleman noted. “Any sport where a person is competing against others to obtain one object, there’s a risk for injury, whether it’s because of an athlete’s own poor biomechanics or a collision with another player,” she explained.

A literature review pointed out that “the tolerance limits of the physis may be exceeded by the mechanical stresses of sports such as football . . . American football is the sport most often connected with acute physeal fractures,” for example, a place kicker who sustains a stress injury of the distal femoral physis, or a “clipping injury” fracture of the epiphysis.6 Clipping injuries occur when a player is blocked or tackled from the lateral side at knee level with the foot firmly planted.7

The repetitive physical loading required in baseball, gymnastics, and distance running may lead to apophyseal injuries, which are usually related to overuse.

“I see more of the chronic overuse injuries, but that may be because I do primary care sports. The true growth-plate injuries, the physeal injuries, they go to the ED first, and then they are more likely to be sent to orthopedics, especially the more severe types of growth-plate fractures,” Coleman noted.

Molony pointed out that overuse injuries in kids will manifest differently than in adults, even if they participate in the same sport. He cited Sever disease as an overuse injury that looks different based on the patient’s age and stage in life. In a child, “the apophy­sis exists where the tendon attaches to the bone; the Achilles tendon attaching to the heel. So, an adult runner may develop Achilles tendinitis. In the skeletally immature population, the Achilles tendon is generally going to be fine. It’s the growth center at the calcaneus where it attaches that gets irritated.”

As for Osgood-Schlatter disease, Molony noted overuse that would cause infrapatellar tendinitis in the lower extremities of an adult would be more apt to cause apophysitis at the tibial tubercle in the skeletally immature athlete.

Spotting physeal injuries

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Pinpointing physeal injuries is vital, as kids will continue to mature physically so “that timing is important—the younger a child is, the sooner that bone starts to try to heal [on its own],” Weiss stated. “In a four-year-old, you probably have a week to ten days to really recognize that injury and move the growth plate back into place. With an eighteen-year-old, you might have up to two weeks because the bone is not trying to heal itself as quickly.”

But, as Coleman noted earlier, most young patients who sustain an acute injury will first present to the ED or a trauma center, and it’s at this first line of medical care where physeal injuries can be misdiagnosed.

A study that looked at four years of diagnostic errors in the ED of a general hospital in England found that, of 108 ankle fractures missed on x-rays, eight were later diagnosed as epiphyseal avulsion fractures.9

X-rays may not tell the whole story when it comes to diagnosing suspected physeal fractures. Molony gave the example of a young athlete presenting at urgent care or the ED with a physeal injury. “They may get plain films, but that Salter Harris Type I fracture may be missed because that fracture line goes through the physis. On plain films, the physis is ‘clear,’ so there’s no crack to see, so to speak. Also, it may not be gapped at all.”

Without definitive imaging information, a thorough clinical exam is paramount. Practitioners should start with asking the patient, “What happened?”

“I ask for a very detailed description from the child as to the circumstances of the injury,” Weiss said. “Even a four-year-old can describe what happened. I’ve found that if the circumstances of the injury are something they can’t really remember, then the chances of it being a break are fairly low. People tend to remember whatever happened that caused a broken bone. Then I ask the parents to weigh in after I’ve spoken to the child.”

Molony recommended the practitioner ask the patient to point to the area of maximal pain with just one finger. “Often, they will point to the bone rather than the soft tissue, but you have to pay close attention to that,” he said. “Don’t rely just on verbal explanation of where the pain is; ask the person to point to it directly with one finger because that helps with the accuracy. Then confirm that point of maximal tenderness through the [clinical] exam.”

Coleman emphasized that practitioners need to conduct what she called a secondary survey. “Make sure to evaluate above and below the injury so you can determine if there could be another injury that isn’t hurting as much as the one the patient is complaining about at the time,” she noted. “Let’s say the patient is complaining about knee pain—we also look at the hip, the ankle, the skin, and the general area around the injury.”

Another option is to ask if the family has any footage of the incident. “At least once a week, I have a parent with an injured child who comes in and shows me the video of what happened, which is great,” Weiss said. “I think it’s safe to say that dancers and gymnasts always have video.”

Experts also agreed it’s important not to give into bias and go for the easiest or most extreme diagnosis.

“You may suspect that it’s a sprain, but don’t base your [clinical] evaluation on that suspicion,” Coleman warned. “Just because you don’t see an obvious injury on the x-ray doesn’t automatically mean the child only has a sprain.”

On the other hand, “the physis isn’t always injured,” Molony said. “It may well be an ankle sprain or a soft tissue injury. But you want to take the time to rule out any possible physeal injuries before making a definitive diagnosis. Assume a physeal injury until you have evidence that shows otherwise.”

Even if the x-ray has limited value, it’s still worth obtaining, Weiss said. “If a kid comes in complaining of hip, groin, or buttock pain, I get an x-ray. I don’t just chalk that up to a groin sprain or a hamstring pull because if there is avulsion fracture and it is missed, even if the treatment is not going to change, then we need to acknowledge that there is a piece of bone broken.”

One way to identify a Salter Harris Type I is through a widening of the physis, Molony said, but to a practitioner who isn’t familiar with a potential widening, “it can be difficult to tell on plain film whether it’s widened or not.”

How to handle this lack of definitive imaging data? One option would be to obtain a bilateral x-ray and compare the affected and unaffected sides, Molony suggested, though that still requires a certain degree of familiarity with the appearance of a healthy physis.

Weiss said she does not send patients with suspected physeal injuries, but inconclusive x-ray results, for MRI scans because “the MRI isn’t going to change my management. If I have a child who has a nondisplaced break through the growth plate of the ankle, I’m going to treat them with a cast or a walking boot, and I’m going to do the same if it’s a sprain.”

Shalmali Pal is a freelance writer in Tucson, AZ.

This is the first part of a two-part series on physeal injuries. Look for part two, which will cover management and physeal issues in anterior cruciate ligament reconstruction (a procedure that itself can lead to growth disturbance) in our July issue.

REFERENCES
  1. Merkel DL, Molony JR JT. Recognition and management of traumatic sports injuries in skeletally immature athlete. Int J Sports Phys Ther 2012;7(6):691-704.
  2. Pediatric Entities in Sports Medicine: Most Common Sports Injuries for Children. SportsmedMD website. http://www.sportsmd.com/youth-sports/common-sports-injuries-children/. Accessed May 12, 2017.
  3. Strayer SM, Reece SG, Petrizzi MJ. Fractures of the proximal fifth metatarsal. Am Fam Physician 1999;59(9):2516-2522.
  4. Hatch RL, Alsobrook JA, Clugston JR. Diagnosis and management of metatarsal fractures. Am Fam Physician 2007;76(6):817-826.
  5. DiFiori JP, Benjamin HJ, Brenner JS, et al. Overuse injuries and burnout in youth sports: a position statement from the American Medical Society for Sports Medicine. Br J Sports Med 2014;48(4):287-288.
  6. Caine D, DiFiori J, Maffulli N. Physeal injuries in children’s and youth sports: reasons for concern? Br J Sports Med 2006;40(9):749-760.
  7. Rogers LF, Jones S, Davis AR, et al. “Clipping injury” fracture of the epiphysis in the adolescent football player: an occult lesion of the knee. Am J Roentgenol Radium Ther Nucl Med 1974;121(1):69-78.
  8. Moore MN. Orthopedic pitfalls in emergency medicine. South Med J 1998;81(3):271-318.
  9. Guly HR. Diagnostic errors in an accident and emergency department. Emerg Med J 2001;18(4):263-269.
  10. Gidwani S, Jagiello J, Bircher M. Avulsion fracture of the ischial tuberosity in adolescents – an easily missed diagnosis. BMJ 2004;329(7457):99-100.
  11. Kennedy JE, Irwin GJ, Huntley JS. Growth arrest lines and intra-epiphyseal silhouettes: a case series. BMC Res Notes 2017;7:27.

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