Recently, Golden State Warriors superstar, Kevin Durant, suffered a potential career-ending lower extremity injury during the NBA finals. Several podiatric online newsletters have posted commentary on this event. Many question whether this athlete should have been cleared to play after suffering a previous injury to his calf muscle. This prior issue affected the same leg on which he subsequently ruptured his Achilles tendon. Rather than second-guessing a decision made by a well-qualified medical team, one can learn a lesson about the complicated effects of multiple injuries on the optimal function of a high-level athlete.
On May 9th, one month prior to his right Achilles tendon rupture, Durant suffered a non-contact injury to the same lower leg in a playoff game against the Houston Rockets. Video shows him grabbing the lower calf area just above the Achilles tendon.The next day, magnetic resonance imaging (MRI) confirmed a “right calf strain.”1 After four weeks of rest and rehabilitation, on June 10th, Durant was cleared to practice.
That same day, with the Warriors in a three to one deficit to the Toronto Raptors, Durant was cleared to play in Game 5 of the NBA Finals. In his first 12 minutes of action, Durant showed no evidence of impairment, scoring 11 points and hitting on all three of his three–point attempts. Then, in the second quarter, Durant fell to the ground as he pushed off of his right foot in a plantarflexed ankle position. In severe pain, he had to be helped off the court. The next day, a new MRI confirmed a complete rupture of his right Achilles tendon. Durant has undergone surgical repair of his Achilles and faces a long and questionable road to recovery.
Several ex-NBA athletes immediately blamed the Golden State Warriors medical team for allowing Kevin Durant to play in Game 5. However, Mr. Durant himself indicated it was he who wanted to get back on the court, feeling ready to play.2,3 Others have defended the doctors who made the return-to-play decision.4
How can a calf strain create risk for an Achilles rupture? Common sense would dictate that a strained calf, most likely the medial head of the gastrocnemius muscle, would be weaker than healthy muscle and could not generate enough tension to rupture its own tendon. An excellent systematic review of causative factors for acute Achilles tendon ruptures does not even mention a preexisting calf strain as a risk factor.5
Let me clarify that I have no additional details regarding the specific nature of the initial calf muscle injury sustained by Kevin Durant. The MRI findings of that injury have been kept confidential by the Warriors. It is possible that the MRI results did show some involvement of the Achilles in the initial injury or perhaps involvement at the myotendinous junction. Let’s assume that the injury was purely a “calf strain” as reported in the press. Could there be any link between that injury and the subsequent Achilles rupture?
I have given many lectures over the years on the subject of chronic ankle instability. In these presentations,I have shown a YouTube video of Kobe Bryant suffering a severe left ankle sprain against the Dallas Mavericks in March 2011.6 He had suffered a severe sprain in the same ankle five days prior in a game against the Atlanta Hawks. In March 2013, he suffered another severe left ankle sprain, again against the Atlanta Hawks. Finally, one month later, in April 2013, he ruptured his left Achilles tendon.
What has been overlooked, with respect to Kevin Durant, is reporting of a similar history of ankle sprains prior to his Achilles tendon rupture. On March 2ndof this year, he sprained his right ankle and had to be taken out of a game against the Philadelphia 76ers. Eight days later, he resprained the same right ankle and suffered a bone contusion, resulting in several missed games.
The significant effects of a single ankle sprain on neuromuscular control over the entire lower extremity are well known.7,8 With multiple ankle sprains, as suffered by both Bryant and Durant, there is a neurologic “disconnect” that occurs at all levels of the sensorimotor system. This can render the athlete vulnerable to further injury.9,10 Multiple studies have demonstrated that after recurrent ankle sprain, athletes have altered hip biomechanics during dynamic balance testing, altered ankle biomechanics during gait and abnormalities during jump landings.11-14 The calf muscle is a critical part of the somatosensory system in that it provides proprioception tothe ankle joint via the muscle spindles.7 It appears that Kevin Durant could have been impaired by previous ankle sprains as well as a recent calf muscle injury.
Push-off during a jump shot and other basketball moves require complex stabilization of the lower extremity joints. Coordinated cocontraction of agonist and antagonist muscles ensures proper stiffness and stability of these joints.15-18 With the impairment of ankle joint motor control that occurs with chronic ankle instability,it is possible that an athlete can place abnormal torque upon the Achilles tendon during a push-off maneuver. Moller and coworkers determined that lack of coordinated activation of the gastrocnemius and soleus muscles establishes a shearing force in the Achilles.19
Unfortunately, we can not always detect subtle levels of sensorimotor impairment in athletes after ankle injury. In order to make a return-to-play decision, we can perform clinical tests but there are many factors we cannot measure.20 When a subsequent injury occurs after a return to play, we do not always know if this was mere coincidence or whether there was impairment we should have identified.
While there is always security in holding the athlete back, there are many external factors as well as pressures placed on the medical staff during NBA Finals or similar series that influence decision making. A compelling factor is the athlete himself or herself who insists he or she is ready to play. Often times, it is the obligation of the physician to override the athlete based upon superior knowledge and training. It is clear that release of a professional-level athlete to play after any injury is a complex decision-making process. It is important, however, to consider both logical and evidence-based factors when asserting our professional medical opinions.
Dr. Richie is an Adjunct Associate Professor within the Department of Applied Biomechanics at the California School of Podiatric Medicine at Samuel Merritt University in Oakland, Calif. He is a Fellow and Past President of the American Academy of Podiatric Sports Medicine. Dr. Richie is a Fellow of the American College of Foot and Ankle Surgeons.
- McCauley J. MRI confirms strained right calf for Kevin Durant. National Basketball Association website. https://www.nba.com/article/2019/05/09/kevin-durant-goes-locker-room-leg-injury. Published May 9, 2019. Accessed June 18, 2019.
- Gleeson S. Charles Barkley thinks Warriors should shoulder all the blame for Kevin Durant’s injury. USA Today. June 11, 2019. https://www.usatoday.com/story/sports/nba/warriors/2019/06/11/charles-barkley-warriors-should-shoulder-blame-on-kevin-durant-injury/1421485001/ . Published June 11, 2019. Accessed June 18, 2019.
- Thomas E. Kevin Durant should not have been playing, period. Athletes need their own doctors. The Guardian. https://www.theguardian.com/sport/2019/jun/13/kevin-durant-shouldnt-have-been-playing-period-athletes-need-their-own-doctors?CMP=share_btn_tw. Published June 13, 2019. Accessed June 18, 2019.
- Doctor slams Kevin Durant, Warriors surgery narrative. The Science Articles website. https://thesciencearticles.com/doctor-slams-kevin-durant-warriors-surgery-narrative/. Accessed June 18, 2019.
- Claessen FM, de Vos RJ,Reijman M, Meuffels DE. Predictors of primary achilles tendon ruptures. Sports Med. 2014;44(9):1241–1259.
- Kobe Bryant sprains left ankle. YouTube website. https://www.youtube.com/watch?v=_unNYpNfb2c . Accessed June 18, 2019.
- Richie DH. Functional instability of the ankle and the role of neuromuscular control: a comprehensive review. J Foot Ankle Surg. 2001;40(4):240-251.
- Beckman SM, Buchanan TS. Ankle inversion injury and hypermobility: effect on hip and ankle muscle electromyography onset latency. Arch Phys Med Rehabil. 1995;76(12):1138–1143.
- Munn J, Sullivan SJ, Schneiders AG. Evidence of sensorimotor deficits in functional ankle instability: a systematic review with meta-analysis. J Sci Med Sport. 2010;13(1):2–12.
- Sefton JM, Hicks-Little CA, Hubbard TJ, et al. Segmental spinal reflex adaptations associated with chronic ankle instability. Arch Phys Med Rehabil. 2008;89(10):1991–1995.
- Gribble PA, Hertel J, Denegar CR. Chronic ankle instability and fatigue create proximal joint alterations during performance of the Star Excursion Balance Test. Int J Sports Med. 2007;28(3):236–242.
- Delahunt E, Monaghan K, Caulfield B. Altered neuromuscular control and ankle joint kinematics during walking in subjects with functional instability of the ankle joint. Am J Sports Med. 2006;34(12):1970–1976.
- Caulfield B, Crammond T, O’Sullivan A, Reynolds S, Ward T. Altered ankle muscle activation during jump landing in participants with functional instability of the ankle joint. J Sport Rehabil. 2004;13(3):189–200.
- Caulfield B, Garrett M. Functional instability of the ankle: differences in patterns of ankle and knee movement prior to and post landing in a single leg jump. Int J Sports Med. 2002;23(1):64–68.
- Louie JK, Mote CD Jr. Contribution of the musculature to rotatory laxity and torsional stiffness at the knee. J Biomech. 1987;20(3):281–300.
- Sinkjaer T, Toft E, Andreassen S, Hornemann BC. Muscle stiffness in human ankle dorsiflexors: instrinsic and reflex components. J Neurophysiol. 1988;60(3):1110–1121.
- Rack PM, Ross HF, Thilmann AF, Walters DK. Reflex responses at the human ankle: the importance of tendon compliance. J Physiol. 1983;344:503–524.
- Beckman SM, Buchanan TS. Ankle inversion injury and hypermobility: effect on hip and ankle muscle electromyography onset latency. Arch Phys Med Rehabil. 1995;76(12):1138–43.
- Moller JB, Hansen P, Aagaard P, Svantesson U, Kjaer M, Magnusson PS. Differential displacement of the human soleus and medial gastrocnemius aponeuroses during isometric plantar flexor contractions in vivo. J Applied Physiol. 2004;97(5):1908-1914.
- Richie DH, Izadi FE. Return to play after an ankle sprain: guidelines for the podiatric physician. Clin Podiatr Med Surg. 2015;32(2):195-215.