Injuries can affect skeletal maturation and performance

November 1, 2006

MRI is providing valuable clinical information that is enabling injured Olympic divers to get their careers back on track.

MRI is providing valuable clinical information that is enabling injured Olympic divers to get their careers back on track.

Recognition of the patterns of injury is important, according to research conducted in the U.K. Injuries to platform and springboard divers occur most often in the hand and wrist during entry and in the foot and ankle during take-off. They can also occur in the spine due to hyperextension and rotation during backward rotational dives from higher platforms and in the shoulder due to hyperextension and abduction.

"The literature about injuries sustained through diving is limited, although gymnastic and other injuries have been well documented," said Dr. Sripriya Suresh of the department of radiology at Derriford Hospital in Plymouth. "Injuries in divers are uncommon, but can have a serious impact on skeletal maturation, performance, and training. Occasionally, they can curtail a diving career."

Along with Dr. Laurie Baxter of the British Diving Association and Dr. D. Gay from the Plymouth Hospitals Trust, Suresh reviewed the MR examinations of injuries sustained by 33 elite divers between 2000 and 2005. The group presented its findings at the 2006 U.K. Radiological Congress in Birmingham.

A total of 12 divers required investigation for spinal injuries. The spine is subjected to extremes of loading at entry and constant flexion, extension, and rotational forces during dives and simulated training exercises, Suresh said.

Most of these patients complained of chronic low back pain, while five complained of acute pain. The MRI findings of chronic low back pain were mainly disk degeneration, but two patients demonstrated pars defects. There was one case of a stress reaction in the pedicle rather than the pars. STIR or fat-suppressed sequences are indispensable for acute and chronic presentations and identifying marrow edema in stress reactions and fractures or soft-tissue ligamentous injury, the researchers found.

One 18-year-old female diver experienced acute low back pain after a reverse high-platform dive, requiring aggressive hyperextension to avoid an under-rotated entry. Axial STIR MRI revealed marrow edema in the spinous process breaching the cortex. A fracture of the spinous process was confirmed on CT. The diver returned to competitive action after six weeks by executing the same dive responsible for her injury: a triple-back off a high platform with pike.

In another case, an initial MR examination on a 16-year-old female with chronic low back pain demonstrated a high signal on a STIR image in the pedicle of L5. This was less evident on the T2-weighted turbo spin echo, Suresh said. CT showed sclerosis at the site. A stress reaction was diagnosed, and a follow-up MRI at 18 months confirmed resolution of the marrow abnormality.

Five divers underwent shoulder MRI. Three examinations were performed to investigate for chronic pain conditions and two were conducted for acute injuries, one of which was an acute rotator cuff tear.

In one case, a 17-year-old female developed shoulder pain with no acute precipitating event. An initial MRI demonstrated bone marrow edema, and her diving program was modified. The symptoms recurred eight months later, and an MR examination showed extensive acromial edema and a clearly defined defect (an evolving stress fracture through a congenital weakness at the site of apophyseal fusion) not seen on the previous scan.

"It would have been tempting, without the initial scan, to diagnose an unstable os acromiale," Suresh said. "This case demonstrates that such lesions may evolve. The patient was also considered on clinical grounds to have glenohumeral internal rotation deficit."

In the study, wrist injuries accounted for 10 of the 33 cases. Most of these were skeletally immature injuries resulting from relative weaknesses of the physis. In one diver who suffered an acute injury due to an incorrect entry, MRI revealed a small perforation of the triangular fibrocartilage complex, but most divers present with a low-grade wrist pain usually of two to three months duration, according to the researchers. These divers' injuries were mainly due to stress responses in bone, and five injuries affected the unfused growth plates.

One diver had edema in the trapezoid and capitate, and another had only subcutaneous bruising. The sigmoid shape of the growth plate is typical of chronic axial overloading in this group. Thickening and deformity of the growth plate are more common on the extensor aspect of the plate due to the hyperextended position of the wrist at entry. The sigmoid configuration of the physis indicates a rocking action of the epiphysis under excessive axial loading. This loading can be reduced using wrist supports.

Three divers were investigated for foot and ankle pain. Two had experienced acute inversion injuries, one having an occult fifth metatarsal fracture, the other anterior capsular injury. A third diver had posterior talar impingement, possibly provoked by extreme ankle extension.

"Such injuries will also be encountered in other aspiring divers," Suresh said. "T2 gradient-echo images often underestimate or miss marrow and soft-tissue edema indicative of injury. Also, STIR sequences in at least one plane are essential to the diagnosis of low-grade stress injuries in bone and soft tissues."

In the shoulder, the team advocates the inclusion of high axial images to identify stress fractures of the acromion. Posterior labral tears and greater tuborosity may indicate posterior impingement. In the spine, sagittal and axial STIR should be included because this increases the yield of stress fractures in the pedicles and pars, as well as acute soft-tissue injuries.

In the wrist, coronal and sagittal STIR images are considered most important, supplemented by coronal and sagittal T1-SE images. The distal radial growth plate must be carefully reviewed for stress changes. In older divers, postphyseal fusion and marrow edema indicates a stress fracture or reaction. In the ankle, injuries are less sport-specific in pattern than other sites, and posterior impingement may be due to ankle hyperextension.