Sex may play a role in patient outcomes after acute Achilles tendon rupture, according to data presented at the 2014 American Orthopaedic Society for Sports Medicine annual meeting. The study found that, overall, male patients had better functional outcomes at 1 year compared to females, regardless of treatment method. In addition, males treated surgically had better outcomes at 6 and 12 months than females who were treated surgically.

“A few studies have reported differences in outcomes in males versus females after treatment for Achilles tendon rupture, but there have been conflicting results,” noted Karin Gravare Silbernagel, PT, ATC, PhD, of the University of the Sciences in Philadelphia, explaining the impetus for the study. “Women account for only 20 percent of patients with Achilles tendon ruptures; therefore, studies rarely have adequate power to perform comparisons between men and women regarding treatment methods and outcomes.”

Obtaining data
The researchers conducted two large, randomized, controlled trials that used identical outcome measures. In these consecutive studies, patients were divided into two groups, receiving either surgical or conservative treatment. In total, 184 patients (154 males, 30 females), with a mean age of 40 years, participated in the studies. A total of 96 patients (78 males, 18 females) received surgical treatment, while 88 patients (76 males, 12 females) underwent conservative treatment.

Investigators used the Achilles Tendon Total Rupture Score (ATRS) to obtain patient-reported outcomes. In addition, at 6 months and 12 months after injury, they measured functional outcomes using the single-leg standing heel-rise test, which measures muscular endurance and heel-rise height.

Analyzing results
Based on the ATRS data obtained at 6 months and 12 months after injury, no significant differences in outcomes were found between those who received surgical treatment and those who received conservative treatment. However, the surgical group had significantly better outcomes than the nonsurgical group in heel-rise endurance at 6 months and 12 months, and in heel-rise height recovery at 6 months (P < 0.03).>

When comparing patient outcomes based on sex, the researchers found no significant differences in outcomes, regardless of treatment method, except at 12 months, at which time males had a greater improvement in heel-rise height (P = 0.004).

Among surgical patients, females had significantly more symptoms (P < 0.04) than males at 6 months and 12 months after treatment, based on atrs data. researchers did not find a similar difference when comparing male and female patients who received conservative treatment.>

“It was surprising that the difference we found when comparing male and female outcomes in the surgical group was not present in the nonsurgical group,” noted Dr. Silbernagel.

“The other finding—that women had a greater degree of deficit in heel-rise height compared to men, regardless of treatment method—was not as surprising,” she said. “We do not know whether this difference is permanent or whether women are just not fully recovered at 12 months.”

Drawing conclusions
“In a way, I think the study poses more questions than answers,” acknowledged Dr. Silbernagel.

In her view, however, the study’s most important clinical takeaway is that “women may respond differently than men to treatment for acute Achilles tendon rupture.”

Some reports have indicated, said Dr. Silbernagel, that a tendon’s response to exercise differs, depending on a patient’s sex.

“Proposed reasons for these differences include hormonal, neuromuscular, and biomechanical factors,” she said.

Thus, basing treatment on results of studies that have included mostly male participants may not be appropriate, Dr. Silbernagel asserted.

“Further research is needed to determine if women might benefit more from nonsurgical treatment than men do,” she added.

Dr. Silbernagel’s coauthors for “Gender Differences in Outcomes after an Acute Achilles Tendon Rupture” included Katarina Nilsson-Helander, MD, PhD; Nicklas Olsson, MD; Annelie Brorsson, PT; Bengt I. Eriksson, MD, PhD; and Jon Karlsson, MD, PhD.

Disclosure information: Dr. Olsson and Ms. Brorsson—no information available; Drs. Silbernagel, Nilsson-Helander, and Karlsson—no conflicts; Dr. Eriksson—Astellas, Bayer Healthcare, Boehringer Ingelheim, Bristol-Myers Squibb, Takeda.

Jennie McKee is a senior science writer for AAOS Now. She can be reached at mckee@aaos.org

Bottom Line

• Data from two large, randomized, controlled studies suggest that sex may affect outcomes after acute Achilles tendon rupture.
• Study findings indicated that, overall, male patients in both treatment groups had better outcomes at 1 year compared to female patients, regardless of treatment method.
• At 6 months and 12 months after injury, females treated surgically had more symptoms than males who were treated surgically.
• More research is needed to determine whether women may benefit more from nonsurgical treatment than men do.