A 20-year-old man developed pain in right lower leg 3 days ago after playing soccer for 3 hours. He had no specific medical history. The symptom was watched over because he thought himself to have a muscle sprain then. From the next morning, ankle dorsiflexion and greater toe extension power started to get lost, and the patient visited the emergency room.

In physical examination, direct tenderness and soft tissue swelling were observed in the lateral side of the affected lower leg; motor grade of ankle dorsiflexion and greater toe extension was measured at 0/5, and hypoesthesia in the outer region of the right foot and 2nd and 3rd metatarsal bones region was found. Pulses from dorsalis pedis artery and posterior tibial artery were well-palpitated. Intracompartmental pressure (ICP) measurement was performed with a slit catheter and the ICP within the lateral compartment of the lower leg was 40 mmHg. Magnetic resonance imaging (MRI) was performed for the right lower leg and signal increase limited to peroneus longus muscle and peroneus brevis muscle was observed in T1 and T2 images (Fig. 1).

In the light of such clinical features and imaging examination results, isolated lateral compartment syndrome in the lower leg was diagnosed and fasciotomy was performed along the axis of the fibula. The aseptic dressing was done postoperatively with the surgical site opened and surgical loop tightening (Fig. 2). After 4∼5 days from the initial surgery, additional wound debridement and sequential wound suture were done. From 15 days after the first procedure, the surgical site came out to be clean and a secondary suture was conducted (Fig. 3).

In the electromyography conducted 20 days after injury, signal loss in deep peroneal nerve was observed and in physical examination, right ankle dorsiflexion and greater toe extension exercise were both measured at 1/5 and right ankle plantarflexion observed at 3/5, deep and superficial peroneal nerve sensation was measured up to 50% (Table 1).

Four months after the date of initial surgery, ankle dorsiflexion and greater toe extension motor improved to 4/5, and active ankle dorsiflexion and plantarflexion range of motion were measured to be 10° and 40°, each. The peroneal nerve sensation was still measured at 50%. At 6 months, peroneal nerve sensation recovered up to 60%, and range-of-motion was recovered as much as the same level compared with the unaffected side (Fig. 4, Table 2). At 1 year after initial surgery, superficial peroneal nerve sensation recovered up to 100% and deep peroneal nerve sensation remained 60%. In electromyography, improved patterns were observed in the lower leg muscles except for extensor digitorum brevis muscle (Table 3). In the telephone call done in twenty-one months postoperatively, all of his sensations were improved.

A 28-year-old man had pain in the right lower leg after having a motorcycle accident 4 weeks before hospitalization. He had no specific medical history. When he got injured, he had severe pain of visual analog scale 8 points, but the pain subsided and eventually disappeared so that he watched over the symptom at home. But starting from 1 week after the initial trauma, right foot dorsiflexion power started to weaken. The weakness showed timely aggravation and in 4 weeks after the initial trauma, the patient eventually showed right foot drop. At this point, the patient visited our center as an outpatient.

In the physical examination, direct tenderness or soft tissue swelling in right lower leg was not prominent; he complained of sensory loss in the entire region of the top of the foot in the front part; motor grade of foot invertor muscle was measured at 5/5 and foot evertor muscle at 4/5, but tibialis anterior muscle 2/5, extensor hallucis longus muscle 0/5, and extensor digitorum longus muscle 0/5. The pulses in dorsalis pedis artery and posterior tibial artery were well-felt. ICP measurement was performed with a slit catheter and the ICP within the lateral compartment of the lower leg was 30 mmHg. In the MRI taken right after the first visit, a signal increase in T2 images limited to peroneus longus muscle and peroneus brevis muscle was observed (Fig. 5). In electromyography, signal depression in the right deep and superficial peroneal nerve and posterior tibial nerve was observed (Table 4).

In light of such findings, isolated lateral compartment syndrome in a lower leg was diagnosed, but at the time when he was hospitalized, pain or edema in the lateral compartment of a right lower leg was mild. It was thought that he was under the improving phase and determined to perform conservative treatment which included initial non-weight bearing, anti-inflammatory drug medication, and gradual physical therapy.

Three months after the initial trauma, motor grade of foot invertor muscle 5/5, foot evertor muscle 5/5, tibialis anterior muscle 3/5, extensor hallucis longus muscle 0/5, and extensor digitorum longus muscle 0/5 were observed, and deep and superficial peroneal nerve sensation was measured at 50% or so. Six months after injury, motor grade of foot invertor muscle was improved to 5/5, foot evertor muscle 5/5, tibialis anterior muscle 4/5, extensor hallucis longus muscle 3/5, and extensor digitorum longus muscle 4/5 with deep and superficial peroneal nerve sensation at 60%. Nine months after injury, which was a final follow-up, all motor grade of foot invertor muscle, foot evertor muscle, tibialis anterior muscle, and extensor hallucis longus muscle improved to motor grade 4/5 (Table 4). In terms of range of motion, right ankle dorsiflexion was measured to be 20° and greater toe extension to be 70°. Superficial and deep peroneal nerve sensation improved up to 80%. In follow-up electromyography, posterior tibialis nerve was normal and the signal of deep and superficial peroneal nerve improved compared to the previous tests. In telephone call done in 2 years after injury, sensory and motor both were fully recovered.