Long-term trends in carpal tunnel syndrome

Abstract

Objective: To assess temporal trends in carpal tunnel syndrome (CTS) incidence, surgical treatment, and work-related lost time.

Methods: Incident CTS and first-time carpal tunnel release among Olmsted County, Minnesota, residents were identified using the medical records linkage system of the Rochester Epidemiology Project; 80% of a sample were confirmed by medical record review. Work-related CTS was identified from the Minnesota Department of Labor and Industry.

Results: Altogether, 10,069 Olmsted County residents were initially diagnosed with CTS in 1981-2005. Overall incidence (adjusted to the 2000 US population) was 491 and 258 per 100,000 person-years for women vs men (p < 0.0001) and 376 per 100,000 for both sexes combined. Adjusted annual rates increased from 258 per 100,000 in 1981-1985 to 424 in 2000-2005 (p < 0.0001). The average annual incidence of carpal tunnel release surgery was 109 per 100,000, while that for work-related CTS was 11 per 100,000. An increase in young, working-age individuals seeking medical attention for symptoms of less severe CTS in the early to mid-1980s was followed in the 1990s by an increasing incidence in elderly people.

Conclusions: The incidence of medically diagnosed carpal tunnel syndrome (CTS) accelerated in the 1980s. The cause of the increase is unclear, but it corresponds to an epidemic of CTS cases resulting in lost work days that began in the mid-1980s and lasted through the mid-1990s. The elderly present with more severe disease and are more likely to have carpal tunnel surgery, which may have significant health policy implications given the aging population.

Figure 1 Symptom characteristics and EMG results of 156 patients with classic/probable or possible carpal tunnel syndrome (CTS) from review of a random sample of 194 charts Thirty-eight of the charts did not reference finger location of symptoms and were excluded. Criteria for a positive nerve conduction study (NCS) include median palmar distal latency more than 2.3 msec, median-to-ulnar palmar latency difference exceeding 0.3 msec when the palmar latency was 2.2 msec or less, or a median antidromic sensory latency more than 3.6 msec with a normal ulnar antidromic sensory latency.

Figure 2 Age-adjusted (women, men) and age- and sex-adjusted (both sexes combined) incidence per 100,000 person-years for carpal tunnel syndrome diagnosis (A), carpal tunnel release surgery (B), and work-related carpal tunnel syndrome with lost work days (C), among Olmsted County, Minnesota, residents, 1981–2005 For details on the process of submitting a First Report of Injury form for work-related injuries, see www.doli.state.mn.us/fr01info.html.