Fatigue fracture often occurs in inexperienced hikers and in recruits at the beginning of their military service. Therefore, the fatigue fracture at the metatarsal bone is also called march fracture. Typical stabbing or dull pain in the area of the metatarsus (metatarsalgia) is characteristic. The load-bearing capacity of the foot is reduced, walking hurts without any outwardly recognizable cause.
The foot is a complexly structured part of the human musculoskeletal system with numerous bony, ligamentous, tendinous and muscular structures. They are connected by several joints and capsules. In evolution, the original gripping and climbing foot was transformed into a stance and running foot with corresponding changes in biomechanical requirements [3]. Homo sapiens today achieves a walking performance in his lifetime that is equivalent to walking around the earth 2 to 3 times and taking around 160 million steps. The complexity of the skeletal structure also makes the foot a site of frequent overuse injuries and damage. In Germany, about 1 million ankle injuries are counted each year. With age, stress and degeneration lead to flattening of the arch of the foot, reduction of the plantar fat pad and coordinative mobility. As a result, about one in three adults complains of local discomfort.
Several pathologic changes in the heel have been discussed in previous articles. In this article, the fatigue fracture of the calcaneus is addressed.
Fatigue fractures of the ankle and metatarsus originally became known because of “marching fractures” in recruits. Due to sports overuse, the number of pathological fractures is also progressive in the civilian population. These can occur on several skeletal parts of the ankle and foot region. Occasionally, spontaneous fractures are also found in ribs in patients with chronic cough, and quite commonly in the spine or pelvic skeleton in elderly patients with osteoporosis or other diseases of bone metabolism [4,5]. Here, the age of women with osteoporotic fracture of the calcaneus is on average 6 years higher than that of men [7], and the measured bone density is in each case lower than the average value of men of comparable age groups with fatigue fracture. Also, inflammatory bony or structural changes, such as osteomyelitis or aneurysmal cysts of the corpus calcanei may reduce osseous resistance and predispose to pathologic fracture [1,2]. Therefore, even in younger patients with heel pain after weight bearing, the morphologic changes should be considered and a fracture should be excluded.
Radiographs may show intraosseous compression about 10 days after the onset of pain if a fatigue fracture is clinically suspected [6], but this is nonspecific. If, with appropriate history and clinic, radiographs do not show any change suspicious of fracture, further workup should be performed by MRI [4].
Computed tomographic examinations are somewhat inferior to MRI in fracture detection, but may better visualize the fragment situation if fragmentation occurs. Quantification of bone density on qCT is exemplary.
Magnetic resonance imaging is the method of choice in imaging occult fractures, especially march fractures. Bone marrow edema is visualized very well, tender fissures can be delineated, and accompanying soft tissue edema can be detected very well.
Case studies
Case report 1 shows the CT and MRI images (Fig. 1A and B) of a 79-year-old patient with a calcaneus fracture. There were many years of cortisone therapy for rheumatism. 3 years prior to imaging, trauma had resulted in distal tibial fracture, which is residually still evident on MRI in addition to arthritis of the ankle and tarsal regions. The small dorsal calcaneal spur can be seen better on CT.
Case report 2 shows a central calcaneus fracture without adequate trauma and a small fracture line in the processus anterior calcanei in a follow-up of a 90-year-old female patient with osteoarthritis in the ankle and tarsus (Fig. 2A and B).
Case report 3 demonstrates a fatigue fracture of metatarsal 3 (Fig. 3A and B) in a sports-obsessed 52-year-old lady who went hiking for “relief” as an alternative to jogging despite pain symptoms in the metatarsal region.
Case report 4 shows in a 60-year-old female patient osteodensitometrically (Fig. 4) a far advanced osteoporosis with a calcium salt content of 26.8 mg/cc, corresponding to 25% of the age average value with a significantly increased fracture risk (related to the age group 100%).
Literature:
- Babazadeh S, et al: Pathologic fracture of a calcaneal aneurysmal bone cyst. J Foot Ankle Surg 2011; 50(6): 727-732.
- Brucato MP, Wachtler MF, Nasser EM: Osteomyelitis of the Calcaneus with Pathologic Fracture. J Foot Ankle Surg 2019; 58(3): 591-595.
- Gabel J: Functional analysis of the foot, Trauma and Occupational Disease 2015; 17: 4-9.
- Ito K, et al: Insufficiency fracture of the body ot the calcaneus in elderly patients with osteoporosis: a case report of two cases. Clin Orthop Relat Res 2004; 422: 190-194.
- Morris JM: Fatigue fractures. Calif Med 1968; 108(4): 268-274.
- Rückert KF, Brinkmann ER: Fatigue fractures of the calcaneus in soldiers of the Federal Forces. Munch Med Wochenschr 1975; 117(16): 681-684.
- Rupprecht M, et al: The calcaneus as the site of manifestation for osteoporosis-associated fractures: age- and sex-specific changes in calcaneal morphology correlate with the incidence and severity of intra-articular calcaneal fractures. Trauma Surgeon 2007; 110(3): 197-204.
HAUSARZT PRAXIS 2021; 16(9): 48-49
