acl graft trends in nfl athletes cover

Acl injury and graft trends in NFL players

introduction

Anterior cruciate ligament (ACL) injury is one of the most common sports-related injuries and its incidence has been increasing in all levels of competition.  In a 12-year period in the United States alone, rates of anterior cruciate ligament reconstruction (ACLR) increased significantly from 10.36 to 18.06 and from 22.58 to 25.42 per 100 000 person-years for women and men, respectively [1].  In the National Football League (NFL), there were 219 ACL injuries in just a 3-year period, also with an increased injury rate per year [2]. 

Almost all individuals who watch sports are aware of ACL injuries, mostly due to the stigma around them and recovery time.  Acute knee injuries are a part of any sports medicine practice and it is important for providers to be aware of recent trends.  Due to the popularity of the NFL, many patients and families may have questions about the most recent trends.  This post is not designed to argue superiority of any choice.

A recent systematic review of the literature after ACLR in elite athletes demonstrated that 83% returned to a similar level of sport and that 5.2% sustained a subsequent graft rupture [3].   In the NFL, only 61% of defensive players who underwent ACLR successfully returned to play at least half a season.  They also tended to retire sooner and to have fewer appearances and a decreased number of solo tackles.  Other sports and studies have shown that statistics worsen and athletes are most likely to retire early [4].

Despite the popularity of BPTB autograft use in elite athletes in the USA, it should be noted that this is not the most popular graft choice in the world among a diverse patient population. In an international survey on ACLR reconstruction practices of 261 surgeons from 57 countries, HS autograft was the most popular graft choice (63%), followed by BPTB (26%) and then allograft (11%).  Hamstring autografts were the preferred graft choice for the majority of European surgeons and surgeons from other countries (72% and 66%), whereas it was the preferred graft choice for only 42% of North American surgeons [9].

There are regional differences regarding graft choice for ACLR in elite soccer players. Hamstring (HS) autografts are used more often in Sweden than in Europe (67% vs 34%), with no apparent differences in time to return to play after ACLR [5].  In the USA, 68% of MLS physicians prefer bone–patellar tendon–bone (BPTB) autograft for ACLR in elite soccer players [6].  Similar trends exist with other sports in the USA as BPTB autograft is the preferred graft of choice for NHL,  NFL and NCAA American Football athletes [7-8].

Recent studies and meta-analyses have found that BPTB autografts have lower failure rates [20-21] and less residual anterior knee laxity and instability compared with HS autografts [22].  Proponents of BPTB cite the advantages of bone-to-bone healing compared with soft-tissue allografts since bone-to-bone healing is similar to fracture healing and it is faster and stronger than soft-tissue healing [23].  It has also been shown that bone grafts can be healed to the host bone within 6 weeks, whereas soft-tissue grafts take 8–12 weeks to fully incorporate [24]. 

Trevon Diggs ACL

Image 1.  Trevon Diggs of the Dallas Cowboys was one of the high profile NFL players that sustained an ACL injury while in practice.

However, there is an increased incidence of anterior knee pain following ACLR.  In a meta-analysis of 21 studies, BPTB autografts had an incidence of anterior knee pain of 17.4% vs 11.5% in HS autografts [25].  It has been suggested that anterior knee pain after ACL surgery may be related to loss of motion and poor rehabilitation rather than graft choice.

Besides graft choice, there is also significant variability in the tunnel drilling preferences of physicians performing ACLR in elite athletes.  There is debate on whether or not transtibial drillings place the tunnel within the native ACL footprint [10-11].  Additional studies challenge that non-anatomical tunnel placement results in inferior restoration of joint kinematics compared with anatomical ACLR achieved by independent, transportal drilling [12].  A study evaluating ACLR practice patterns in elite athletes in the USA showed that 44.7% of surgeons drilled the femoral tunnel through a transtibial portal, 36.2% through an anteromedial (AM) portal and 12.8% by a two-incision technique [13].  Interestingly, on an international survey performed in 2011, 68% of surgeons performed AM portal drilling over the traditional transtibial portal (31%) [9].

More recently, treatment patterns for NCAA division I football athletes seems to be evolving.  One study over a 10-year period showed that the preference for BPTB reconstruction for primary ACLR increased from 67% in 2008 to 83% in 2016 (p<0.0001) among orthopedic team physicians [14].  Most recently, quadriceps tendon (QT) autograft is being increasingly used as an autograft option in many athletes, including elite athletes [15]. The QT autograft has gained popularity as an alternative graft option for primary or revision ACLR due to its versatility. It can be harvested as a full or partial thickness graft with or without a bone block (BB) [27].  More studies are underway to compare the BPB and QT outcomes and return to play.

Nick Chubb injury

Figure 1.  Nick Chubb of the Cleveland Browns recently suffered an ACL injury in an NFL game.

The percentage of NCAA American Football physicians who allowed RTS within 6 months or less after ACLR was significantly higher than that of NFL surgeons when compared to NHL and NCAA athletes [16].  In addition, there are differing opinions regarding postoperative bracing among surgeons of professional athletes. In Erickson et al’s study, 70.2% of surgeons did not recommend bracing during play on RTS. In NFL and NCAA American football, most surgeons do not recommend a brace on RTS in running backs [13].  Interestingly however, prophylactic knee bracing was used at a significantly higher rate by NCAA teams versus NFL teams (89% vs 28%) [17].

Some providers have proposed an anatomical, individualized ACLR in the elite athlete.  This requires an understanding of the variation that exists among individuals regarding the size and shape of the native ACL and its femoral and tibial insertion sites [18-19].  This requires more presurgical planning and the ability to alter technique.  Anatomical, individualized ACLR aims to restore the function of the native ACL by customizing ACLR to best match the patient’s native ACL insertion, knee bony anatomy and particular athletic needs.  

Individualized ACL planning

Figure 3.  Examples of measurements over ACL origin and insertion .  Adopted from [28].

The percentage of NCAA American Football physicians who allowed RTS within 6 months or less after ACLR was significantly higher than that of NFL surgeons when compared to NHL and NCAA athletes [16].  In addition, there are differing opinions regarding postoperative bracing among surgeons of professional athletes. In Erickson et al’s study, 70.2% of surgeons did not recommend bracing during play on RTS. In NFL and NCAA American football, most surgeons do not recommend a brace on RTS in running backs [13].  Interestingly however, prophylactic knee bracing was used at a significantly higher rate by NCAA teams versus NFL teams (89% vs 28%) [17].

Some providers have proposed an anatomical, individualized ACLR in the elite athlete.  This requires an understanding of the variation that exists among individuals regarding the size and shape of the native ACL and its femoral and tibial insertion sites [18-19].  This requires more presurgical planning and the ability to alter technique.  Anatomical, individualized ACLR aims to restore the function of the native ACL by customizing ACLR to best match the patient’s native ACL insertion, knee bony anatomy and particular athletic needs.  

Summary

In conclusion, the management of ACL injury in the elite athlete is challenging, given its implications on the athletes’ longevity, contractual or scholastic obligations and revenue-generating-potential. The trend for NFL players and treating orthopedic physicians has been the BPTB graft, although the QT has become more popular with NCAA football players.

– More Knee Pain: https://www.sportsmedreview.com/by-joint/knee/

– More ACL info at Wiki Sports Medicine: https://wikism.org/ACL_Tear

References

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  3. Lai, Courtney CH, et al. “Eighty-three per cent of elite athletes return to preinjury sport after anterior cruciate ligament reconstruction: a systematic review with meta-analysis of return to sport rates, graft rupture rates and performance outcomes.” British journal of sports medicine 52.2 (2018): 128-138.
  4. Read CR, Aune KT, Cain EL, Fleisig GS. Return to Play and Decreased Performance After Anterior Cruciate Ligament Reconstruction in National 
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