Perspective

Survival, return-to-play rates after microfracture varied among sports

Outcomes differed for microfracture surgery and ACL reconstruction among athletes.

After microfracture surgery, National Basketball Association athletes had a higher-than-average probability of return to play, but there was a decline in their performance and a reduced number of games played 1 season after surgery, according to presented results. However, by seasons two to three post-surgery, the reduction in games played was recoverable to baseline.

National Football League (NFL) players had the lowest probability of return to play, based on the results.

“The data from this study suggest that knee microfracture surgery has the potential to negatively impact postoperative performance and career longevity for professional athletes,” Michael S. Schallmo, BS, said. “We found that return rates, return times and performance-based outcomes following microfracture varied significantly depending on sport.”

Return to play after microfracture

Schallmo, Wellington K. Hsu, MD, and their colleagues identified 131 athletes who underwent primary, unilateral microfracture of the knee while on the active roster of the NFL, National Basketball Association (NBA), National Hockey League (NHL) or Major League Baseball (MLB). They calculated performance scores by sport using previously established scoring systems and compared players across different sports by adjusting for season and career length differences between sports, as well as by calculating percent change in performance.

“Successful return to play was defined as returning for at least one professional regular season game after surgery,” Schallmo said. “Return to play time was defined as the number of days elapsed between the date of surgery and date of first professional game back.”

Schallmo noted the average time to return to play was 293 days and a successful return to play occurred in 78.6% cases, which varied according to sport.

“Baseball players returned at a significantly higher rate than all other sports, and football players returned at a lower rate than all other sports,” he said during a presentation.

Players with a higher ratio of preoperative games started to games played were seven-times more likely to return to sport. Results among basketball players showed a significant reduction in adjusted games played in 1 season after surgery vs. the index season, according to Schallmo.

Survivorship, roster retention

“Survivorship analysis found 67% of players who successfully returned were expected to still be on professional rosters 1 season after surgery and 43% after 3 years with no significant differences between sports,” Schallmo said.

There was an overall median survival of 2.8 years after surgery with a significantly longer median survival among baseball players and a shorter mean survival among football players, he said.

A significant decrease in performance during postoperative season one was found among baseball and basketball players, according to Schallmo, who said there was a continued decrease in performance during postoperative seasons two and three seen for basketball players.

“Notably, football players, who comprised the greatest proportion of athletes in this study, did not show a significant reduction in performance after returning,” Schallmo said.

Schallmo noted these findings contrast with findings of ACL reconstruction in athletes in which football players had significantly reduced performance up to 3 years after ACL reconstruction compared with basketball players who recovered to baseline 2 years after ACL reconstruction.

“These differences highlight the potential impact of sport on postoperative expectations after different operations of the knee,” he said. “The daily collisions of American football players may place greater stress on an ACL-reconstructed knee compared to one with microfracture, while running on grass or turf may lead to a lower risk of symptoms from an osteochondral defect,” Schallmo said. – by Casey Tingle

Disclosures: Hsu and Schallmo report no relevant financial disclosures.

After microfracture surgery, National Basketball Association athletes had a higher-than-average probability of return to play, but there was a decline in their performance and a reduced number of games played 1 season after surgery, according to presented results. However, by seasons two to three post-surgery, the reduction in games played was recoverable to baseline.

National Football League (NFL) players had the lowest probability of return to play, based on the results.

“The data from this study suggest that knee microfracture surgery has the potential to negatively impact postoperative performance and career longevity for professional athletes,” Michael S. Schallmo, BS, said. “We found that return rates, return times and performance-based outcomes following microfracture varied significantly depending on sport.”

Return to play after microfracture

Schallmo, Wellington K. Hsu, MD, and their colleagues identified 131 athletes who underwent primary, unilateral microfracture of the knee while on the active roster of the NFL, National Basketball Association (NBA), National Hockey League (NHL) or Major League Baseball (MLB). They calculated performance scores by sport using previously established scoring systems and compared players across different sports by adjusting for season and career length differences between sports, as well as by calculating percent change in performance.

“Successful return to play was defined as returning for at least one professional regular season game after surgery,” Schallmo said. “Return to play time was defined as the number of days elapsed between the date of surgery and date of first professional game back.”

Schallmo noted the average time to return to play was 293 days and a successful return to play occurred in 78.6% cases, which varied according to sport.

“Baseball players returned at a significantly higher rate than all other sports, and football players returned at a lower rate than all other sports,” he said during a presentation.

Players with a higher ratio of preoperative games started to games played were seven-times more likely to return to sport. Results among basketball players showed a significant reduction in adjusted games played in 1 season after surgery vs. the index season, according to Schallmo.

Survivorship, roster retention

“Survivorship analysis found 67% of players who successfully returned were expected to still be on professional rosters 1 season after surgery and 43% after 3 years with no significant differences between sports,” Schallmo said.

There was an overall median survival of 2.8 years after surgery with a significantly longer median survival among baseball players and a shorter mean survival among football players, he said.

A significant decrease in performance during postoperative season one was found among baseball and basketball players, according to Schallmo, who said there was a continued decrease in performance during postoperative seasons two and three seen for basketball players.

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“Notably, football players, who comprised the greatest proportion of athletes in this study, did not show a significant reduction in performance after returning,” Schallmo said.

Schallmo noted these findings contrast with findings of ACL reconstruction in athletes in which football players had significantly reduced performance up to 3 years after ACL reconstruction compared with basketball players who recovered to baseline 2 years after ACL reconstruction.

“These differences highlight the potential impact of sport on postoperative expectations after different operations of the knee,” he said. “The daily collisions of American football players may place greater stress on an ACL-reconstructed knee compared to one with microfracture, while running on grass or turf may lead to a lower risk of symptoms from an osteochondral defect,” Schallmo said. – by Casey Tingle

Disclosures: Hsu and Schallmo report no relevant financial disclosures.

    Perspective
    Brian R. Waterman

    Brian R. Waterman

    Surface chondral defects are frequently found among active patient subsets with reported rates of up to 63% in patients undergoing knee arthroscopy in large-scale series. Despite more favorable return to sport rates with other restoration techniques, such as osteochondral autograft transfer, chondroplasty and marrow stimulation techniques continue to be embraced as the most common interventions. However, concerns exist about the performance and midterm to long-term viability of microfracture-induced fibrocartilage, particularly among high-impact athletes. Schallmo and colleagues identified that 79% of 131 professional athletes in MLB and the NBA, NFL and NHL were able to successfully return to play after microfracture, although performance metrics demonstrated comparatively worse outcomes than their premorbid, baseline state. Average time to return to play was 0.8 years, and a ratio of total career games started to games played correlated positively with the likelihood of return to play. Pertinent study limitations include the potential for significant selection bias due to reliance on public reporting, lack of statistical power, indeterminate longer-term outcomes and absence of patient-reported outcomes. Although microfracture and other palliative techniques continue to predominate, we must critically evaluate the functional and subjective patient outcomes after these interventions.

    References:

    Curl WW, et al. Arthroscopy. 1997;doi:10.1016/S0749-8063(97)90124-9.

    McCormick F, et al. Arthroscopy. 2014;doi:10.1016/j.arthro.2013.11.001.

    Widuchowski W, et al. Knee. 2007;doi:10.1016/j.knee.2007.02.001.

    • Brian R. Waterman, MD
    • Associate professor, department of orthopedic surgery Assistant fellowship director, sports medicine Wake Forest University School of Medicine Winston-Salem, North Carolina

    Disclosures: Waterman reports no relevant financial disclosures.

    Perspective
    Jason L. Dragoo

    Jason L. Dragoo

    The study by Schallmo and his colleagues is instructive because it adds much-needed data to the observed variability of return to play after microfracture surgery in the elite athlete. There is definitely a trend to avoid microfracture in treatment algorithms, as it appears to injure the subchondral bone and lead to a variable healing response. The bone can heal normally, but may also heal with cysts and hypertrophic changes leading to continued symptoms after returning to play.

    The study may overestimate the true return to play as it uses participation in only one game to qualify as full return after surgery. Further tracking of the number of games played after return will reveal the true participation status and longevity of returning to play.

    • Jason L. Dragoo, MD
    • Associate professor Head team physician, Stanford football program Stanford University Redwood City, California

    Disclosures: Dragoo reports no relevant financial disclosures.