By Abby Sims
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Brook Lopez, the Brooklyn Nets' 7-foot center, is reportedly in a walking boot after undergoing his third foot surgery in two years, this time to replace the bent hardware stabilizing his right fifth metatarsal. Though this isn't another re-fracture, a period of rest and rehab will follow.
The initial injury, diagnosed as a non-displaced stress fracture, occurred in December of 2011 and was immediately followed by fixation surgery. After missing 32 games, Lopez played in only five games before re-injuring the foot and having another procedure. Rest and rehab claimed the balance of that season. This scenario is not that atypical: re-fracture of the proximal fifth metatarsal following surgical fixation has been reported in the literature to occur anywhere from 5 percent to 40 percent of the time depending on the study.
Lopez recovered sufficiently to put up All-Star numbers in the 2012-2013 campaign, missing action only in early December due to what was alternately reported as a foot sprain or an ankle issue (depending on the publication), either of which was deemed unrelated to his original metatarsal problem. Discovery of the bent screw evidently occurred with imaging studies in a routine post-season check-up rather than because the player complained of pain. The forces such a big man places on such a small area in the course of playing clearly make a vulnerable spot that much more susceptible to re-injury.
Explaining Stress Injuries
Bony stress injuries are fairly common amongst those whose activities entail running, jumping or marching (military personnel). They are considered overuse injuries and – unlike traumatic fractures – appear due to cumulative overload over a period of time. The small bones of the feet – the metatarsals (view image) – collectively suffer the majority of stress injuries. The heel bone (calcaneus), bones of the midfoot, and those of the lower leg (tibia and fibula) are also often victims of this injury. Sports putting a premium on leanness, such as long distance running, dancing and gymnastics all increase risk. Overuse and loading of the upper extremities can also result in upper body stress injuries.
Stress Reaction Versus Stress Fracture
Excessive and repetitive loading on weight-bearing bones can cause "fatigue damage". Stress reactions – the less severe of these diagnoses – are bony abnormalities that are evident with diagnostic testing but do not entail disruption of the cortex, the outer shell. In contrast, stress fractures progress from Stage 1 to Stage 3, and in each the degree of cortical cracking becomes more extensive leading ultimately to failure. Simple x-rays often do not reveal evidence of stress injuries until healing is well underway and the calcification "lights up" the area. That is why MRI's and bone scans are so helpful. Earlier diagnosis – as soon as symptoms appear – along with rest and treatment can prevent a stress reaction from progressing to a stress fracture.
Other Predisposing Factors:
Those with hormonal irregularities or low bone density (osteopenia or osteoporosis) are at higher risk of developing stress responses. Athletes suffering from disordered eating (preponderantly women), are particularly prone, even in the heavier bone of the thigh (femur). Runners or other athletes with these conditions are also more likely than others to develop pubic bone or sacral area (very low back) pain due to stress fractures in these bones.
Additionally, those with very flat (pronated) feet or with very high arches (cavus feet) may have an increased risk of exhibiting stress responses or stress fractures in the bones of the foot. Metabolic bone diseases as well as muscle weakness or imbalances can also predispose to stress injuries. Increased incidence has also been reported due to smoking and excessive alcohol consumption.
Two Major Types Of Fifth Metatarsal Fractures
Avulsion Fractures, which entail a chipping of bone, are common in dancers and occur at the base of the metatarsal. These generally occur with forced motion of the foot into inversion – twisted such as for an outer ankle sprain – while the foot is also a pointed (ankle plantar flexion).
Jones Fractures and Stress Fractures occur in a different area of the fifth metatarsal, above the base, or a bit closer to the toes. This area of the proximal shaft of the bone is called the metaphyseal-diaphyseal junction. These fractures are similar except that the Jones fracture is a simple fracture and does not show evidence bony stress on imaging. Both generally occur when the athlete's ankle is plantar flexed while the forefoot is on the ground and a lateral force is applied. In basketball, this might occur during a plant and pivot maneuver, when landing on one foot from a jump as is done following a lay-up, or when landing on another player's foot.
Conservative treatment for Type I - Jones Fracture – and Type II fractures is fairly common in the non-athlete population. This entails non-weight bearing in a cast or walking boot and using crutches for six to eight weeks. Patients progress to ambulation with increasing degrees of weight-bearing. The period of non-weight bearing may have to be extended if union of the bone has not been achieved. Delayed healing is not unusual. That is why conservative treatment of these fractures is not the treatment of choice for most athletes. Instead surgical fixation is recommended in an effort to improve fracture healing, decrease recovery time, and diminish the time away from competition.
Surgical intervention is required to address Type III nonunion fractures. This is primarily due to the poor blood supply to the fracture site – the metaphyseal-diaphyseal junction. In the athletic population – once again – this is the case regardless, because operative treatment is associated with more predictable healing. X-rays are repeated during the post-op period until union is achieved. Fortunately, in Brook Lopez's case, they were performed even afterward as a precaution.
Note: Those interested in information on rehab of an athlete following metatarsal fracture might want to consult this article by Dave Englehardt.
Additional reference: Wheeless' Textbook of Orthopaedics.
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