Cath Lab Digest

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Index: Ostomy Wound Manage. 2008;54(9):18-32.

  Mobility impairment is an unintentional and largely unrecognized consequence of injection drug use (IDU). This impaired mobility in combination with other potential pathologic changes to the veins, muscles, and joints of the lower legs from IDU may lead to the development of chronic venous disorders (CVD). Chronic venous disorders of the lower extremities may cause swelling, varicose veins, skin damage, refractory ulcers, and pain¹ — progressive and debilitating sequelae. Injection drug users with CVD often complain of mobility problems such as difficulty with walking, stair climbing, and working.^2,3 Previous research4 found evidence of CVD in 87% of persons in a methadone maintenance treatment program; by contrast, additional research found CVD affects 7% to 9% of the general population and occurs late in life.^3,4

   The calf muscle pump is a critical component of the conceptual model describing the relationship between CVD and mobility impairments. In addition to its role in a functional venous system, the calf muscle pump is dependent on ankle joint flexion for the compression motion that leads to venous emptying by forcing venous return to the central circulation.⁵ Changes to the musculoskeletal system of the lower leg can adversely affect the dynamics of the calf muscle pump.

   The standing heel-rise test (the ability to perform consecutive heel rises) is an easily administered, noninvasive measure of the calf muscle pump’s strength and endurance. As an extension of their previous work,^6,7 the authors examined the heel-rise test as a measure of ankle mobility, test-retest reliability, and validity related to CVD and mobility in persons who injected in different sites. The test assesses the eccentric-concentric muscle action of plantar flexion.⁸ Ankle plantar flexion strength has an important role in standing balance, walking, and most activities of daily living.⁹ People with weak plantar flexors may have difficulty walking, running, and jumping and may exhibit fatigue – the inability to maintain the expected force and power output to perform consecutive heel rises.¹⁰ The heel-rise test may provide a method to explore potential muscular function and mobility problems in persons who inject drugs. The test has not been examined in persons who injected drugs; thus, this reliability/validity phase is important.

Literature Review

   Two studies address the heel-rise test in persons with a history of deep vein thrombosis (DVT) and CVD. Haber et al¹¹ examined test-retest reliability of the heel-rise test on one leg of 40 healthy persons (median age 24 years) and on the unaffected leg of 38 persons (median age 51 years) who were > 1 year post-DVT. The median number of heel lifts for the healthy group was 34 and the intraclass correlation coefficient (ICC) was 0.93 at both 30 minutes and 48 hours. Participants with a history of DVT performed slightly fewer heel rises (median of 27 heel rises) with a test-retest ICC for a minimum of 7 days of 0.88. The authors neither reported statistical testing on the heel-rise difference between the healthy and DVT groups nor gave an explanation for why the unaffected leg was used.

   van Uden et al12 examined heel rise and gait in 19 healthy volunteers (M age = 51.4 years) and 15 persons with current or healed venous ulcers (M age = 59.9 years). Participants with venous disease performed significantly fewer heel rises (14.6±7.34) than the healthy controls (23.5±6.54).