Safety of Hamstring Harvest: Wheeless' Textbook of Orthopaedics

The semitendinosis and gracilis tendons are often used in orthopaedics for reconstruction of ACL deficient knees as well as being used for reconstructions of the shoulder, elbow, ankle, and foot. The question arises for this research study (hamstring arthroplasty) is specifically, what are the risks and long term morbidity of hamstring harvest?

Specific risks and morbidity of hamstring harvest include saphenous nerve damage (1,12,13) and weakness (2-11). In terms of hamstring harvest, the avoidance of saphenous nerve damage depends on experience and careful technique. The issue of weakness is more complicated. In general, it can be demonstrated that there is a 7-21% weakness of knee flexion strength when measured with specialized equipment. (4,10) More important, however, it is also demonstrated that over time, the hamstring tendons regenerate (14,15) and strength improves over time (3), and the knee flexion weakness does not appear to interfere with activities of daily living and sports, as determined by objective research studies. (2,3,6,8).

In terms of objective weakness using specific testing equipment it is clear that there is some residual weakness following hamstring harvest.
In the study by Burks et al (Arthroscopy 2005)⁴, the authors utilized isokinetic testing on hamstring harvest patients and determined that "at 12 months the mean 60 degrees/second deficit was 21% and the deficit at 180 degrees/second was 13%. (4) In another study by Condouret et al (Rev Chir Orthop Reparatrice Appar Mot., 2008)¹⁰, the authors noted that an "average deficit of 14 to 18%" in hamstring harvest patients. (10)

It is well documented, however, that the hamstring tendons regenerate (14,15), postoperative weakness improves, and that the residual weakness demonstrated on isokinetic testing machines does not appear to be clinically significant. In the study by Simonian et al (Arthroscopy 1997)⁶, the authors evaluated patients that had had hamstring harvest and noted that "the average percent quadriceps and hamstring strength of the operated compared with the non operated extremities were 93.7% and 95.3%". They concluded "that tendon harvest of the semitendinosus and gracilis muscles does not significantly compromise function and strength despite a more proximal insertion of the retracted tendons." (6)
In another recent study (Ardern, Arthroscopy 2010)², the authors conclude that "these findings show that the choice of hamstring tendon graft-that is, semitendinosus alone or semitendinosus and gracilis-is unlikely to significantly influence postoperative hamstring strength outcomes in athletes returning to sports postoperatively." (2)
In the report by Samuelsson et al (Arthroscopy 2009) ³ the authors attempted "summarize and assess current evidence from randomized controlled trials (RCTs) on anterior cruciate ligament injuries, with special reference to graft type and surgical technique." They noted that
"semitendinosus and gracilis tendon harvesting probably reduces hamstring muscle strength for approximately 1 year."
In the study by Takeda et al (Am J Sports Med, 2006)⁸, the authors used an MRI study to evaluate function after hamstring harvest. They concluded that "the semitendinosus and gracilis muscles are able to restore or maintain their contractile capability after harvest of their tendons for anterior cruciate ligament reconstruction, regardless of the degree of regeneration."(8)

Finally, what is most important in the middle aged patient (which are the most likely to undergo autologous hamstring resurfacing), is that hamstring harvest is safe and does not impair function after harvest when used for ACL reconstruction. (16-18). Because the totality of the evidence points to minimal risk and minimal morbidity from hamstring harvest, it is not unexpected that this tendon has been used not only for ACL reconstruction but also for a variety of other types of reconstructive procedures. A medline search has demonstrated the following clinical articles on use of hamstring harvest/reconstruction other than ACL surgery: 9 article for foot and ankle surgery (19-27), 6 articles for shoulder surgery (28-33), 4 articles for elbow surgery (34-37), and 12 articles for knee medial femoral ligament reconstruction (38-49).

In conclusion, there is abundant clinical evidence that hamstring harvest is safe not only for ACL surgery, but also for use in a wide variety of situations in which joint reconstruction is required. There is every reason to expect that hamstring harvest for the purposes of this research study will pose no additional risks than have already been documented in the literature.