The South Dakota Supreme Court issued an opinion Wednesday upholding circuit court and Department of Labor decisions not to require an employer and its insurer to compensate a Hutchinson County man for a 2016 knee replacement.

The court held that Alan Armstrong's fall while working at Longview Farm was not the only or major contributing cause of his need for knee replacement surgery, citing years of existing osteoarthritis and other medical history.

The opinion, written by Justice Mark Salter, stated that Armstrong worked for Longview Farm for more than six years, with the primary responsibility of raising female pigs until they weighed about 300 pounds and were ready to be bred. Armstrong sustained two prior knee injuries in the mid-1990s and in 2005, both while employed at other agricultural facilities.

On March 31, 2016, Armstrong, then 51, was scraping the floor of Longview Farm's hog confinement building when the curved blade he was using caught on the floor, causing him to trip and land on his left leg. Armstrong went to a clinic in Scotland and then to see Sioux Falls, where he was told he had degenerative injuries to his knee and would need to either conservatively treat the knee or have a full knee replacement.

On April 27, 2016, Travelers Property and Casualty, which provided workers' compensation for Longview Farm, sent Armstrong a letter saying it had been determined his knee's condition was due to a chronic and preexisting condition, not directly caused by his fall. Armstrong had both knees replaced on May 2, 2016. One of his artificial knees became infected and required additional surgeries and treatment.

Longview Farm terminated Armstrong on Dec. 5, 2016, and on July 17, 2017, Armstrong filed a complaint alleging that Longview Farm and Travelers had "denied medical and compensation benefits without any reasonable basis."

Orthopedic surgeon Benjamin Bissell was deposed at an administrative hearing before the Department of Labor and said Armstrong had preexisting, severe osteoarthritis before his fall, and he didn't believe the fall was a major contributing factor in his needing knee surgery.

Michael Adler, the surgeon who did Armstrong's knee replacement, was also deposed and disagreed with parts of the other doctor's opinion, saying that although Armstrong would have been eligible for a knee replacement already and his arthritis wasn't made worse by the fall, the March 31, 2016, fall "was bad enough to put him over the edge" and opt for surgery, rather than continuing with other, more conservative forms of treatment.

The Department of Labor found that Bissell's opinion was more persuasive than Adler's. Salter wrote in the Supreme Court's opinion that Bissell's testimony that Armstrong had been a candidate for knee replacement for years and the fact that Armstrong opted to have both knees replaced at once, rather than only the knee he had fallen on at Longview Farm, supported the department's conclusion that there wasn't enough evidence to prove the 2016 injury contributed independently to Armstrong's need for a knee replacement.

"The fact that the March 31 injury may have been the unfortunate tipping point of Armstrong's knee symptoms does not mean that it displaced the degenerative effects of his preexisting condition," Salter wrote.

The Supreme Court considered Armstrong's case in April 2019. Chief Justice David Gilbertson, Justices Janine Kern and Steven Jensen and retired Justice Lori Wilbur concurred with Salter's opinion, which confirmed the circuit court's ruling that upheld the Department of Labor's decision.