Chronic exertional compartment syndrome of the thenar musculature

Abstract

We present the case of a 44-year-old male with complaints of activity-induced, debilitating bilateral hand pain that had been undiagnosed for approximately six years. After extensive evaluation, intra-compartmental pressure monitoring confirmed the diagnosis of chronic exertional compartment syndrome of both the adductor pollicis and the thenar compartments (abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis). A two-incision decompressive fasciotomy was performed and post-operative intra-compartmental pressure measurements pre- and post-exercise were obtained confirming successful treatment of the condition.

1. Introduction

Compartment syndrome is defined by critical pressure increase within a confined compartmental space, causing a decline in the perfusion pressure to the compartment tissue.¹ Most commonly it occurs acutely as a result of high energy trauma in the setting of skeletal fracture but can also occur chronically when induced by exertion or activity. Chronic exertional compartment syndrome (CECS) is an overuse injury that was first described by Mavor in 1956² and is a well-known problem of the lower extremity, typically affecting athletes or military personnel.^{3, 4, 5} CECS of the upper extremity, however, is far less common with most cases described in the forearm.⁶ There have only been a few reports occurring in the adductor compartment,^{7, 8, 9, 10, 11} and we are unaware of reports of CECS in multiple compartments of the hand simultaneously. We present a rare case of a CECS of both the thenar and adductor compartments and describe our diagnostic process, surgical treatment, and clinical outcome. Informed consent was obtained from the patient, and all information has been de-identified.

2. Case report

A 44-year-old right hand dominant male mechanic presented with a six-year history of bilateral thenar eminence and first web space pain. The right was worse than the left and is the focus of this case study. There was no pain at rest. The patient reported that pain was induced with activity such as mechanical work and writing, which required repetitive or constant gripping and grasping. If activity continued the pain would escalate to debilitating 9/10 pain with significant swelling. At presentation, the patient was unable to work.

The patient had seen multiple physicians over the previous six years with provisional diagnoses including basilar thumb arthritis and trigger thumb. He had attempted conservative treatment with NSAIDs and massage, and had received multiple corticosteroid injections to the first carpal-metacarpal joint and A1 pulley without even transient resolution or improvement of symptoms. Prior EMG was negative for compression of the median nerve in the carpal tunnel and X-rays were unremarkable.

On physical exam, the patient's hands appeared bulky and muscular. Skin appeared thick and callused, consistent with his vocation as a mechanic. There were no palpable nodules at the region of the thumb A1 pulley, and no triggering was noted with range of motion of the thumb. A grind test of the thumb carpal-metacarpal joint was negative, and the patient had negative provocative tests for carpal tunnel syndrome. Neurovascular exam was unremarkable. He was able to reach the distal tip of the thumb to the small finger bilaterally.

Due to lack of symptoms at rest and the precipitation of pain by exertion on history, the patient was asked to engage in resisted thumb activity for 5 min. The patient was provided a resistance ball and asked to engage in a combination of key grip and thumb abduction. The patient developed moderate to severe pain. The thenar eminence and the first web space was tense to palpation and notable swelling became evident (Fig. 1).

Fig. 1.

Pre-exercise Fig. 1A and B and post-exercise Fig. 1C and D. Note swelling of thenar eminence and first dorsal web space.

The patient experienced significant pain with passive stretch of the thumb. The patient was unable to oppose the tip of the thumb to the tip of the small finger with a 2.5 cm gap present bilaterally. This clinically supported our suspicion for CESC, and the patient elected to proceed with compartment pressure monitoring before and after exertion.

Compartment pressure monitoring was performed by inserting a Stryker Intra-compartmental pressure monitor (Kalamazoo, MI) into the apex of the thenar eminence at 90° to the skin in the direction of the first metacarpal. It was advanced through skin and into the thenar compartment. The thenar compartment is entered once a “pop” is felt, indicating entrance through the thenar fascia, where a measurement was obtained and recorded. The device was then advanced posterior and ulnar to the first metacarpal through the separating fascia into the adductor compartment. Measurements were again recorded. Resting and exercise compartment pressure measurements were obtained from both the thenar and adductor compartments in the aforementioned fashion. The results are presented in Table 1.

Table 1.

Intracompartmental Pressure Results. For reference, resting diastolic pressure was 85 mmHg.

	Thenar Compartment		Adductor Compartment
	Pre Exercise	Post Exercise	Pre Exercise	Post Exercise
Before Decompressive Fasciotomy	21 mmHg	56 mmHg	27 mmHg	53 mmHg
After Decompressive Fasciotomy	2 mmHg	20 mmHg	7 mmHg	18 mmHg

As the resting compartment pressures were over 15 mm Hg and exercise-induced compartment pressures rose to over 30 mm Hg, the diagnosis of CECS was confirmed. Due to multiple years of pain and inability to perform his desired vocation, the patient elected to proceed with surgical management of his condition - decompressive fasciotomy of the thenar, adductor and first dorsal interossei compartments. Although the compartment pressures of the interossei were not obtained initially, the clinical scenario of swelling and pain in the first web space supported first dorsal interossei as a potential location of CECS, and therefore the decision was made to release the compartment to prevent residual symptoms.

The fasciotomy was performed with incisions over the radial border of the first metacarpal and a second incision dorsal to the second metacarpal allowing access to the thenar and adductor compartments, respectively. Through the dorsal second metacarpal incision the first and second dorsal interosseous compartments were released. To access the adductor compartment origin on the third metacarpal, it is necessary to release the overlying second interosseous compartment. The compartments were inspected for complete release and the skin was then closed leaving the underlying fascia open.

One week post-operatively, the patient was allowed to progress activity as tolerated. After six weeks (Fig. 2), he no longer complained of debilitating pain with activity. To evaluate for complete release, compartment pressure was measured before and after exercise. Pre-exercise compartment testing demonstrated compartment pressures of 2 mm Hg in the thenar compartment and 7 mm Hg in the adductor compartment. The patient again exercised the right hand with resisted pinch activity; after 5 min, a pain level of 3/10 was obtained and failed to increase in severity after an additional 10 min of resisted pinch activity. Measurements at this time were 20 mm Hg and 18 mm Hg in the thenar and adductor compartments, respectively.

Fig. 2.

Post-operative photos demonstrate well healed surgical locations and minimal incision necessary to preform decompressive fasciotomy.

3. Discussion

Chronic exertional compartment syndrome is a condition that results in increased intracompartmental pressure that arises with activity and subsides with rest. Activities which seem to provoke these episodes are typically repetitive or continuous use activities such as gripping or grasping. This increased pressure results in localized pain, decreased muscle function, and swelling. Increased pressure diminishes venous outflow, leading to an increased venous pressure, which in turn decreases the arteriovenous pressure gradient. This leads to diminished capillary flow resulting in insufficient oxygenation of the tissue relative to metabolic demands.¹² In the case presented, the patient developed compartment syndrome due to his repetitive gripping performing activities related to his job as a mechanic. His hypertrophied thenar musculature likely contributed to his decreased reserve for swelling within the fascial compartment.

In this case, the diagnosis was confirmed using pressure monitoring before and immediately after resisted exertion. The patient's elevated resting compartment pressures over 15 mm Hg and his exercise-induced compartment pressures over 30 mm Hg is consistent with the diagnostic criteria for CECS proposed by Pedowitz et al.¹³ After decompression, both resting and post-exercise compartment measurements improved, and he no longer experienced exertional symptoms. A minor increase in compartment pressure is expected with exertion as there is increased flow to the tissues based on oxygen demand, this is reflected in post exercise measurements after decompressive fasciotomy in all compartments measured.

Current literature explores other diagnostic modalities, including magnetic resonance imaging with T2-weighted signal hyper-intensity in the effected compartment and near-infrared spectroscopy that reveals deoxygenation of the muscle.^7,14 Both methods are noninvasive compared to the conventional pressure measurements. In the case of near-infrared spectroscopy, Van Den Brand found a clinical sensitivity equivalent to Intra-compartmental pressure monitoring. However, these methods are potentially associated with high costs, extensive protocols, and lack of widespread training in implementation and diagnosis. At institutions with the training and capabilities to perform these studies, they offer excellent non-invasive methods of diagnoses. The intra-compartmental pressure monitor is the preferred tool for diagnosis of compartment syndrome at our institution. It is also readily available and familiar to most orthopedic surgeons thus preventing further delay in diagnosis.

The described technique in this paper is use of a blind intra-compartmental pressure monitor. Inherent risks with this method are neurovascular injury. The nerves in potential danger are the recurrent branch of the median nerve and digital nerve branches in the first web space, along with the digital arteries. The digital neurovascular bundle is ulnar and deep to the thenar compartment and thus is at a decreased risk of injury with the described technique. Ultrasound could provide a more precise localization of the compartments and decreased risk of neurovascular injury. For those trained in use of ultrasound, this method provides a useful adjunct to compartment pressure monitoring.

The nonsurgical treatment options for CECS are limited to activity modification, physical therapy, and nonsteroidal anti-inflammatory medications. Since this patient's trade required him to use his hands with moderate intensity routinely and conservative approaches had failed, surgical treatment with decompressive fasciotomies were offered to alleviate his pain.

4. Conclusion

This patient suffered from years of chronic pain that resulted in social and economic struggle. Although CECS is a rare condition of the hand, this case demonstrates that CECS should be entertained when conventional testing fails to reveal a diagnosis and successful surgical treatment is available to patients who have failed conservative measures.

Declaration of competing interests

The Authors declare that there is no conflict of interest.

Appendix A. Supplementary data

The following is the Supplementary data to this article: