Femoroacetabular impingement (FAI) syndrome is an increasingly recognized cause of hip pain in athletes. Up to 95% of elite athletes may exhibit at least 1 radiographic finding of cam or pincer morphology.1–3 Symptoms are due to abnormal joint morphology leading to aberrant contact between the proximal femur (cam) and acetabular rim (pincer).4–7 For symptomatic athletes, this can lead to decreased function and performance.7,8 For patients dissatisfied with their hip condition despite nonsurgical treatments, hip arthroscopy with correction of cam and/or pincer morphology and labral preservation is successful in reducing pain and permitting return to sport.9
Previous studies have examined the epidemiology and outcomes of corrective surgery for FAI syndrome in professional athletes, with only 1 study investigating postoperative performance in National Football League (NFL) players.10–13 However, this study was limited to a subset of patients from a single institution. Given this limited evidence and the increasing popularity of professional football, it is important to understand surgical outcomes in these patients.
The purpose of this study was to determine the (1) return-to-sport (RTS) rate of NFL players following FAI surgery, (2) postoperative career length and games per season, (3) pre- and postoperative performance, and (4) postoperative performance compared with control players matched by position, age, years of experience, and performance. The authors hypothesized that NFL players who underwent hip arthroscopy would have (1) an 85% RTS rate, (2) no significant differences in postoperative career length and games per season compared with preoperatively, (3) no significant differences in postoperative performance compared with preoperative, and (4) no significant differences in postoperative performance compared with matched controls.
Materials and Methods
National Football League players who underwent hip arthroscopy for FAI syndrome between 2000 and 2017 were identified through team websites, publicly available internet-based injury reports, player profiles and biographies, and press releases. The search was manually conducted by 2 orthopedic surgery residents (K.R.S., R.A.J.) in December 2017. Searches were performed for all professional teams. This method of data collection has been used successfully in multiple studies of professional athletes, including the NFL.14–20
All players identified were included in this study as it related to RTS rate. A player was deemed to have RTS if he played in any regular season game after surgery. A player did not RTS if he did not play in any game after surgery. Inclusion criteria were any player on an active roster prior to hip arthroscopy for FAI. Players were included if they were found to have undergone hip arthroscopy for FAI as reported by at least 2 separate sources. Data from these databases were verified against each other and through independent web-based searches of team press releases that confirmed the date of surgery for each player.14,15 If this information was unclear, unverified, or unobtainable, then the athlete was excluded. Athletes who were injured and underwent procedures before completing their first regular season were excluded because no preoperative data would be available for comparison. Players who underwent hip arthroscopy for FAI in the 2017 season were excluded from analysis because they had less than a 1-year opportunity to RTS and to have postoperative statistics.
Demographic variables, including a player's age, position, previous professional experience, and date of surgery, were recorded. Players were categorized by their positions, including quarterback, running back, tight end, wide receiver, offensive lineman, defensive lineman, line-backer, defensive back, kicker, or punter. Performance statistics before and after hip arthroscopy for FAI were collected from profootballreference.com for each player identified. Statistics were collected for regular season NFL games only, with preseason and playoff games excluded. There were no players for whom performance data could not be identified. Each performance data category was divided by the games played to account for discrepancies in the number of games played per season. A player's performance score was then calculated by using a previously published and standardized scoring system based on metrics important to the player's specific position.21
Because of the possible benefits or detriments of aging and/or experience in relation to player performance and number of games played, matched control players were selected to use for comparison with post-surgery performance in the surgically treated players. This control group of players was selected by matching the exact position, age (±1 year), years of experience (±1 year), body mass index (±2 kg/m2), and performance data prior to the case's surgery date. To compare postoperative or post-index performance, each control was given an index date that matched the case player's surgery date. For example, if a player had surgery 3 years into his career, the control's index date was 3 years into his career.
A Kaplan–Meier survivorship curve with “retirement” as the endpoint was constructed. The continuous variables of each cohort were compared using a 2-tailed paired samples Student's t test for normally distributed data. The chi-square test was used to analyze categorical data. A Bonferroni correction was used to control for multiple comparisons, with statistical significance set at P≤.007.
Eighty-nine NFL players who underwent hip arthroscopy from 2000 to 2017 were identified. Eighteen players were excluded because they did not undergo FAI surgery. Seven players were excluded because they had either no or less than 1 year of professional experience, and 9 players were excluded because they had less than 1-year follow-up. Fifty-five players (63 surgeries) were analyzed (Figure 1). The mean age was 27.5±3.4 years, and the mean professional experience was 4.7±2.9 years in the NFL at the time of surgery. Four players had staged bilateral procedures, 2 players had revisions, and 1 player had 3 surgeries (staged bilateral procedures followed by a unilateral revision). The largest proportion of players to undergo FAI surgery was offensive line-man at 22%. Fifty-six (88.9%) surgeries occurred outside of the regular season. There were no significant (P>.007) differences in demographic, performance, and games per season data between cases and matched controls pre-surgery and pre-index.
Flowchart illustrating application of exclusion criteria. Abbreviation: NFL, National Football League.
Return to Sport and Career Length
Forty-seven NFL players (53 surgeries, 84.1%) were able to RTS at a mean of 6.7±3.8 months following surgery (Table 1). The overall 1-year survival rate of continued play in the NFL of players undergoing hip arthroscopy for FAI was 79.4% (Figure 2). The mean career length of players in the control group (3.7±2.2 years) was similar (P>.007) to that of players who underwent hip arthroscopy for FAI (3.5±2.1 years) (Table 2).
Return to Sport Rate and Time by Player Position
Kaplan–Meier survival analysis for cases and controls. Zero (0) signifies year of surgery for cases and index year for controls.
Games Per Season and Career Lengths for Cases and Controls by Player Position
Games and Performance Outcomes After Surgery
There was no significant difference in games per season postoperatively compared with preoperatively (P>.007). Players in the control group played in a similar number of games per season post-index compared with players who underwent hip arthroscopy for FAI after surgery (12.5±3.1 vs 12.1±4.0 games per season) (P>.007) (Table 2). Postoperative performance scores were similar for all positions (P>.007) compared with preoperative scores (Table 3, Figure 3). Quarterbacks had significantly better postoperative performance scores when compared with post-index matched controls (P=.007) (Figure 3). There were no other significant differences in postoperative performance compared with post-index matched controls for all other position groups (P>.007).
Performance Scores for Cases Pre- and Postoperatively by Player Position
Performance scores by position before and after surgery compared with controls pre-and post-index. The ■ symbol signifies significant difference between post-surgery and post-index performance scores. Abbreviations: DB, defensive back; DL, defensive lineman; LB, linebacker; QB, quarterback; RB, running back; TE, tight end; WR, wide receiver.
The study hypotheses were partially confirmed. The authors' first hypothesis was not confirmed because of an 84.1% RTS rate vs the authors' hypothesis of 85%. The authors' second and third hypotheses were confirmed, as NFL athletes played in a similar number of games per season and had similar career lengths postoperatively as preoperatively and matched controls. The authors' fourth hypothesis was confirmed among all positions excluding quarterbacks, who had significantly better postoperative performance scores when compared with post-index matched controls.
Previous studies of professional football players have shown RTS rates ranging from 80% to 96% at an average of 6.0 months postoperatively.12,13 This is similar to the mean RTS rate in the current study of 84.1% at 6.8 months. The large variation in RTS rates is likely due to previous studies being limited to the outcomes of a single institution, while the current study investigated all NFL players undergoing hip arthroscopy for FAI. Additionally, RTS time is likely affected by surgeon preference and guidelines for RTS. According to a recent study by Domb et al,22 football was classified as a high-risk sport for hip injury and re-injury following hip arthroscopy, with 70% of surgeons recommending RTS at 3 to 5 months postoperatively. As such, returning too early or too late may have an effect on postoperative performance and/or career longevity in the NFL.
The multifactorial nature of hip arthroscopy for FAI also likely contributed to the varied RTS rates and times in previous studies. Surgeon experience, skill, and/or technique likely play a role in RTS rates, with higher-volume, more experienced surgeons having fewer complications and improved outcomes.23 Additionally, cam or pincer morphology may increase the incidence of soft tissue (labrum, capsule, musculotendinous) injuries around the hip as stress is transferred from the impingement to the surrounding area.24 A previous study examining RTS rates following sports hernia repair showed a significant decline in career length and games per season.25 This increased incidence of sports hernia among players with FAI also may have potentially confounded the RTS rates, times, and performance in this and previous studies.
National Football League athletes played in a similar number of games per season and had similar career lengths following surgery as preoperatively and matched controls. This same trend was seen in the study by Nwachukwu et al,12 with NFL athletes playing 9.5 games per season and having an average career length of 3.5 years following hip surgery. However, this differs from a previous study of NFL players undergoing anterior cruciate ligament reconstruction. These players had significantly shorter career lengths and played in significantly fewer games per season after surgery.21 This was believed to be due to the effect of high body mass index in those NFL athletes, which has been shown to place more stress on the reconstructed ligament and lead to associated intra-articular injuries at the time of anterior cruciate ligament injury.21,26 This same detrimental effect of body mass index on patient outcomes has not been found in patients following hip arthroscopy.27–29 Furthermore, reconstruction of an injured ligament typically requires a longer recovery period prior to RTS compared with hip arthroscopy for FAI. This was also seen in the previous study, with a mean RTS of 12.1 months following anterior cruciate ligament reconstruction among NFL athletes.21
Although not statistically significant, performance scores among linebackers and defensive linemen decreased postoperatively, which aligns with the previous study.12 However, declines in performance scores were also seen among the matched controls for linebackers and defensive linemen and thus are most likely attributable to natural career-based declines rather than a direct result of surgery. Quarterback performance improved postoperatively compared with preoperatively while the performance of the matched controls decreased, leading to a significant difference between cases and controls following arthroscopic FAI surgery. Although not statistically significant, this same trend was seen for running backs, wide receivers, and defensive backs. Interestingly, this is in contrast to the previous study that found both offensive and defensive performance to decrease in postoperative cases and post-index controls using data from 2014.12 The current study used data that are more recent with longer follow-up, providing NFL athletes a longer time to recover and improve their performance following surgery. This indicates that, particularly for these positions, hip arthroscopy for FAI may mitigate the career-based postoperative decline in performance that is typically seen in professional athletes. Studies using comparative trials with large samples are necessary to further investigate and confirm the mechanisms of this finding.
There are limitations to this study and other studies of similar methodology. The use of publicly available data to identify players who underwent hip arthroscopy for FAI may be prone to selection, reporting, and observer bias. However, this method of data acquisition has been used in multiple previous studies.14,15,25,30–37 By only including the highest level of professional players, these data may only apply to elite-level athletes. Professional players have a higher rate of return to play than non-professional players.38 This is believed to be because of the inherently high talent and determination present at this level with higher income potential.11 Additionally, players may retire for reasons not related to performance that cannot be accounted for in this type of study. The authors may not have been able to identify all previous hip surgeries for the included players, which has been shown to have an effect on the outcomes of hip arthroscopy for FAI.39,40 Also, career length and performance were not adjusted for “time missed” for players who underwent hip arthroscopy for FAI. Multiple unknown confounding variables, such as no direct physical contact, patient-reported outcomes, or medical records access to corroborate diagnosis and treatment, are inherent to this type of study. The use of public data limits the ability to determine the chronicity and severity of the injury. In addition, the surgeon who performed the operation or the exact operative procedure used in each hip arthroscopy (labral debridement vs repair vs reconstruction, degree of cam/pincer correction/under-correction/overcorrection, chondral treatments for variable degrees of articular cartilage pathology/arthritis, or capsular closure/repair/plication/shift; periarticular extra-articular peritrochanteric, deep gluteal space, or athletic pubalgia/core muscle injury) could not be reliably determined. Heterogeneity of surgeons or surgeons' experience was also a limitation. Other limitations included the absence of patient-reported outcomes and incomplete follow-up and career length for players still in their respective leagues.
The RTS rate for NFL athletes after hip arthroscopy for FAI is high. The NFL athletes had similar games per season and career lengths postoperatively as preoperatively and matched controls. Quarterbacks had significantly better postoperative performance scores when compared with post-index matched controls, with all other position groups having similar postoperative performance as preoperatively and matched controls.
- Kapron AL, Anderson AE, Aoki SK, et al. Radiographic prevalence of femoroacetabular impingement in collegiate football players: AAOS Exhibit Selection. J Bone Joint Surg Am. 2011;93(19):e111. doi:10.2106/JBJS.K.00544 [CrossRef]
- Nepple JJ, Brophy RH, Matava MJ, Wright RW, Clohisy JC. Radiographic findings of femoroacetabular impingement in National Football League Combine athletes undergoing radiographs for previous hip or groin pain. Arthroscopy. 2012;28(10):1396–1403. doi:10.1016/j.arthro.2012.03.005 [CrossRef]
- Frank JM, Harris JD, Erickson BJ, et al. Prevalence of femoroacetabular impingement imaging findings in asymptomatic volunteers: a systematic review. Arthroscopy. 2015;31(6):1199–1204. doi:10.1016/j.arthro.2014.11.042 [CrossRef]
- Banerjee P, McLean CR. Femoroacetabular impingement: a review of diagnosis and management. Curr Rev Musculoskelet Med. 2011;4(1):23–32. doi:10.1007/s12178-011-9073-z [CrossRef]
- Clohisy JC, Baca G, Beaulé PE, et al. ANCHOR Study Group. Descriptive epidemiology of femoroacetabular impingement: a North American cohort of patients undergoing surgery. Am J Sports Med. 2013;41(6):1348–1356. doi:10.1177/0363546513488861 [CrossRef]
- Clohisy JC, Knaus ER, Hunt DM, Lesher JM, Harris-Hayes M, Prather H. Clinical presentation of patients with symptomatic anterior hip impingement. Clin Orthop Relat Res. 2009;467(3):638–644. doi:10.1007/s11999-008-0680-y [CrossRef]
- Frank JS, Gambacorta PL, Eisner EA. Hip pathology in the adolescent athlete. J Am Acad Orthop Surg. 2013;21(11):665–674. doi:10.5435/JAAOS-21-11-665 [CrossRef]
- Hammoud S, Bedi A, Voos JE, Mauro CS, Kelly BT. The recognition and evaluation of patterns of compensatory injury in patients with mechanical hip pain. Sports Health. 2014;6(2):108–118. doi:10.1177/1941738114522201 [CrossRef]
- Menge TJ, Briggs KK, Dornan GJ, McNamara SC, Philippon MJ. Survivorship and outcomes 10 years following hip arthroscopy for femoroacetabular impingement: labral debridement compared with labral repair. J Bone Joint Surg Am. 2017;99(12):997–1004. doi:10.2106/JBJS.16.01060 [CrossRef]
- Locks R, Utsunomiya H, Briggs KK, Mc-Namara S, Chahla J, Philippon MJ. Return to play after hip arthroscopic surgery for femoroacetabular impingement in professional soccer players. Am J Sports Med. 2018;46(2):273–279. doi:10.1177/0363546517738741 [CrossRef]
- Menge TJ, Briggs KK, Philippon MJ. Predictors of length of career after hip arthroscopy for femoroacetabular impingement in professional hockey players. Am J Sports Med. 2016;44(9):2286–2291. doi:10.1177/0363546516650649 [CrossRef]
- Nwachukwu BU, Bedi A, Premkumar A, Draovitch P, Kelly BT. Characteristics and outcomes of arthroscopic femoroacetabular impingement surgery in the National Football League. Am J Sports Med. 2018;46(1):144–148. doi:10.1177/0363546517729163 [CrossRef]
- Philippon M, Schenker M, Briggs K, Kuppersmith D. Femoroacetabular impingement in 45 professional athletes: associated pathologies and return to sport following arthroscopic decompression. Knee Surg Sports Traumatol Arthrosc. 2007;15(7):908–914. doi:10.1007/s00167-007-0332-x [CrossRef]
- Erickson BJ, Gupta AK, Harris JD, et al. Rate of return to pitching and performance after Tommy John surgery in Major League Baseball pitchers. Am J Sports Med. 2014;42(3):536–543. doi:10.1177/0363546513510890 [CrossRef]
- Makhni EC, Lee RW, Morrow ZS, Gualtieri AP, Gorroochurn P, Ahmad CS. Performance, return to competition, and reinjury after Tommy John surgery in Major League Baseball pitchers: a review of 147 cases. Am J Sports Med. 2014;42(6):1323–1332. doi:10.1177/0363546514528864 [CrossRef]
- Jack RA II, Burn MB, Sochacki KR, McCulloch PC, Lintner DM, Harris JD. Performance and return to sport after Tommy John surgery among Major League Baseball position players. Am J Sports Med. 2018;46(7):1720–1726. doi:10.1177/0363546518762397 [CrossRef]
- Jack RA II, Sochacki KR, Gardner SS, et al. Performance and return to sport after Achilles tendon repair in National Football League players. Foot Ankle Int. 2017;38(10):1092–1099. doi:10.1177/1071100717718131 [CrossRef]
- Jack RA II, Sochacki KR, Navarro SM, Mc-Culloch PC, Lintner DM, Harris JD. Performance and return to sport after nonoperative treatment of clavicle fractures in National Football League players. Orthopedics. 2017;40(5):e836–e843. doi:10.3928/01477447-20170719-03 [CrossRef]
- Sochacki KR, Jack RA II, Hirase T, et al. Performance and return to sport after forearm fracture open reduction and internal fixation in National Football League players. Hand (N Y). 2018;13(6):682–688. doi:10.1177/1558944717726137 [CrossRef]
- Sochacki KR, Jack RA II, Nauert R, et al. Performance and return to sport after thumb ulnar collateral ligament surgery in National Football League players. Hand (N Y). 2018:1558944718760001.
- Mai HT, Chun DS, Schneider AD, et al. Performance-based outcomes after anterior cruciate ligament reconstruction in professional athletes differ between sports. Am J Sports Med. 2017;45(10):2226–2232. doi:10.1177/0363546517704834 [CrossRef]
- Domb BG, Stake CE, Finch NA, Cramer TL. Return to sport after hip arthroscopy: aggregate recommendations from high-volume hip arthroscopy centers. Orthopedics. 2014;37(10):e902–905. doi:10.3928/01477447-20140924-57 [CrossRef]
- Sochacki KR, Jack RA II, Safran MR, Nho SJ, Harris JD. There is a significant discrepancy between “big data” database and original research publications on hip arthroscopy outcomes: a systematic review. Arthroscopy. 2018;34(6):1998–2004. doi:10.1016/j.arthro.2018.01.018 [CrossRef]
- Birmingham PM, Kelly BT, Jacobs R, Mc-Grady L, Wang M. The effect of dynamic femoroacetabular impingement on pubic symphysis motion: a cadaveric study. Am J Sports Med. 2012;40(5):1113–1118. doi:10.1177/0363546512437723 [CrossRef]
- Jack RA, Evans DC, Echo A, et al. Performance and return to sport after sports hernia surgery in NFL players. Orthop J Sports Med. 2017;5(4):2325967117699590. doi:10.1177/2325967117699590 [CrossRef]
- Bowers AL, Spindler KP, McCarty EC, Arrigain S. Height, weight, and BMI predict intra-articular injuries observed during ACL reconstruction: evaluation of 456 cases from a prospective ACL database. Clin J Sport Med. 2005;15(1):9–13. doi:10.1097/00042752-200501000-00003 [CrossRef]
- Gupta A, Redmond JM, Hammarstedt JE, Lindner D, Stake CE, Domb BG. Does obesity affect outcomes after hip arthroscopy? A cohort analysis. J Bone Joint Surg Am. 2015;97(1):16–23. doi:10.2106/JBJS.N.00625 [CrossRef]
- Gupta A, Redmond JM, Hammarstedt JE, Stake CE, Domb BG. Does obesity affect outcomes in hip arthroscopy? A matched-pair controlled study with minimum 2-year follow-up. Am J Sports Med. 2015;43(4):965–971. doi:10.1177/0363546514565089 [CrossRef]
- Saltzman BM, Kuhns BD, Basques B, et al. The influence of body mass index on outcomes after hip arthroscopic surgery with capsular plication for the treatment of femoroacetabular impingement. Am J Sports Med. 2017;45(10):2303–2311. doi:10.1177/0363546517705617 [CrossRef]
- Jack RA, Sochacki KR, Hirase T, et al. Performance and return to sport after hip arthroscopic surgery in Major League Baseball players. Orthop J Sports Med. 2019;7(2):2325967119825835. doi:10.1177/2325967119825835 [CrossRef]
- Amin NH, Old AB, Tabb LP, Garg R, Toossi N, Cerynik DL. Performance outcomes after repair of complete Achilles tendon ruptures in National Basketball Association players. Am J Sports Med. 2013;41(8):1864–1868. doi:10.1177/0363546513490659 [CrossRef]
- Cerynik DL, Lewullis GE, Joves BC, Palmer MP, Tom JA. Outcomes of microfracture in professional basketball players. Knee Surg Sports Traumatol Arthrosc. 2009;17(9):1135–1139. doi:10.1007/s00167-009-0765-5 [CrossRef]
- Harris JD, Frank JM, Jordan MA, et al. Return to sport following shoulder surgery in the elite pitcher: a systematic review. Sports Health. 2013;5(4):367–376. doi:10.1177/1941738113482673 [CrossRef]
- Namdari S, Baldwin K, Anakwenze O, Park MJ, Huffman GR, Sennett BJ. Results and performance after microfracture in National Basketball Association athletes. Am J Sports Med. 2009;37(5):943–948. doi:10.1177/0363546508330150 [CrossRef]
- Namdari S, Scott K, Milby A, Baldwin K, Lee GC. Athletic performance after ACL reconstruction in the Women's National Basketball Association. Phys Sportsmed. 2011;39(1):36–41. doi:10.3810/psm.2011.02.1860 [CrossRef]
- Domb BG, Davis JT, Alberta FG, et al. Clinical follow-up of professional baseball players undergoing ulnar collateral ligament reconstruction using the new Kerlan-Jobe Orthopaedic Clinic overhead athlete shoulder and elbow score (KJOC Score). Am J Sports Med. 2010;38(8):1558–1563. doi:10.1177/0363546509359060 [CrossRef]
- Gibson BW, Webner D, Huffman GR, Sennett BJ. Ulnar collateral ligament reconstruction in Major League Baseball pitchers. Am J Sports Med. 2007;35(4):575–581. doi:10.1177/0363546506296737 [CrossRef]
- Nho SJ, Magennis EM, Singh CK, Kelly BT. Outcomes after the arthroscopic treatment of femoroacetabular impingement in a mixed group of high-level athletes. Am J Sports Med. 2011;(suppl 39):14S–19S. doi:10.1177/0363546511401900 [CrossRef]
- Domb BG, Martin TJ, Gui C, Chandrasekaran S, Suarez-Ahedo C, Lodhia P. Predictors of clinical outcomes after hip arthroscopy: a prospective analysis of 1038 patients with 2-year follow-up. Am J Sports Med. 2018;46(6):1324–1330. doi:10.1177/0363546518763362 [CrossRef]
- Sardana V, Philippon MJ, de Sa D, et al. Revision hip arthroscopy indications and outcomes: a systematic review. Arthroscopy. 2015;31(10):2047–2055. doi:10.1016/j.arthro.2015.03.039 [CrossRef]
Return to Sport Rate and Time by Player Position
|Position||No. of Surgeries||No. (%) to Return to Sport||Mean±SD Time to Return to Sport, mo|
|Running back||4||3 (75.0)||6.0±3.1|
|Tight end||6||6 (100.0)||10.1±7.1|
|Wide receiver||9||8 (88.9)||5.1±1.6|
|Defensive back||8||6 (75.0)||5.9±1.2|
|Defensive line||6||6 (100.0)||8.2±3.0|
|Offensive line||14||10 (71.4)||7.7±3.9|
Games Per Season and Career Lengths for Cases and Controls by Player Position
|Position||No. of Surgeries||Mean±SD Games per Season, No.||Mean±SD Career Length, y|
Performance Scores for Cases Pre- and Postoperatively by Player Position
|Position||Mean±SD Performance Score, points||P|
|Before Surgery||After Surgery|