Patellar Tendon Autograft

Monika Volesky, M.D., FRCSC
Montreal, Quebec

Use of the patellar tendon autograft in ACL reconstruction became prevalent over three decades ago. It has remained the most popular graft choice because of its strength characteristics, rigid initial fixation and favourable clinical outcomes. As recently as 2000, over 80% of members of the American Academy of Orthopaedic Surgeons still preferred using the central third bone-patellar tendon-bone graft in ACL reconstruction and it remains the gold-standard to which all other graft choices are compared1.

Central third patellar tendon autografts require harvesting of a tibial tubercle and patellar bone plug, through either a longitudinal midline incision or two small transverse incisions over the bony insertions of the patellar tendon. The overall width of the patellar tendon determines the size of the graft, which usually consists of the central 10 mm, to a maximum of 40% of the total width. A circular or straight-blade oscillating saw is then used to harvest the bone plugs, with care taken not to notch the patella transversely to prevent fracture. The total length of a typical bone-patellar tendon-bone graft is 90 to 105 mm, which allows for a 25 mm femoral tunnel, 30 mm of intra-articular tendon, and a tibial tunnel of approximately 45 to 50 mm. Some authors routinely harvest the contralateral tendon, allowing faster rehabilitation with no long-term adverse effects2, 3.

From a biologic standpoint, the advantage of a patellar tendon graft is that the graft bone heals to host bone in six weeks, which is faster than the 8 to 12 weeks it takes for soft tissue healing4. Graft fixation is also crucial in the early postoperative period, and interference screw fixation for bone block patellar tendon grafts has demonstrated excellent strength if care is taken not to diverge the screw from the bone block in the tunnels5. Consistent size and shape of the graft, as well as ease of harvest are arguments in favour of the patellar tendon autograft.

Although infrequent, complications with patellar tendon autograft include patellar fractures, patellar tendon ruptures, kneeling pain, tendonitis, and numbness from injury to the infrapatellar branch of the saphenous nerve6. Anterior knee pain has long been thought to be associated with harvest of the patellar tendon, but some authors have suggested that it may be more related to loss of motion and poor rehabilitation techniques rather than graft choice7-9.

Despite the vast amount of literature on graft selection and outcomes in ACL reconstruction, there are few randomized controlled studies comparing the graft choices using contemporary fixation methods. Patellar tendon autograft has long been considered the gold standard, and no conclusive data is currently available to support this claim10. Recently, several systematic reviews were published suggesting that there is no significant evidence to indicate that any one graft is superior with respect to stability, failure rates and clinical scores.11-13 Graft site morbidity, specifically hamstring weakness in the 4-bundle hamstring autograft and increased kneeling pain in the patellar tendon group was seen consistently in the studies evaluated. Authors of meta-analyses fail to agree on subjective differences in anterior knee pain or return-to-activity level10, 14-16.

Obtaining an adequate graft specimen while minimizing donor site morbidity is the goal of graft harvest. Successful ACL reconstruction depends on a number of factors including meticulous tunnel placement, surgical technique and aggressive rehabilitation. Patellar tendon autograft may have some comparative advantages for high-demand athletes who desire a rapid return to play, but certain lifestyle activities such as kneeling for work or prayer are relative contraindications. Since most comparative studies show that outcome is similar regardless of graft choice, the surgeons philosophy and experience as well as patient issues such as activity level, comorbidities and preference should ultimately guide the graft selection.

References

1. Johnson D.H. ACL Made Simple. New York: Springer-Verlag, 2004.

2. Uribe J.W., Hechtman K.S., Zvijac J.E., Tjin A.TEW. Revision anterior cruciate ligament surgery: experience from Miami. Clin Orthop Relat Res 1996:91-9.

3. Shelbourne K.D., Urch S.E. Primary anterior cruciate ligament reconstruction using the contralateral autogenous patellar tendon. Am J Sports Med 2000; 28:651-8.

4. Rodeo S.A., Arnoczky S.P., Torzilli P.A., Hidaka C., Warren R.F. Tendon-healing in a bone tunnel. A biomechanical and histological study in the dog. J Bone Joint Surg Am 1993; 75:1795-803.

5. Caborn D.N., Urban W.P., Jr., Johnson D.L., Nyland J., Pienkowski D. Biomechanical comparison between BioScrew and titanium alloy interference screws for bone-patellar tendon-bone graft fixation in anterior cruciate ligament reconstruction. Arthroscopy 1997; 13:229-32.

6. West R.V., Harner C.D. Graft selection in anterior cruciate ligament reconstruction. J Am Acad Orthop Surg 2005; 13:197-207.

7. Sachs R.A., Daniel D.M., Stone M.L., Garfein R.F. Patellofemoral problems after anterior cruciate ligament reconstruction. Am J Sports Med 1989; 17:760-5.

8. Shelbourne K.D., Trumper R.V. Preventing anterior knee pain after anterior cruciate ligament reconstruction. Am J Sports Med 1997; 25:41-7.

9. Rubinstein R.A., Jr., Shelbourne K.D., VanMeter C.D., McCarroll J.C., Rettig A.C. Isolated autogenous bone-patellar tendon-bone graft site morbidity. Am J Sports Med 1994; 22:324-7.

10. Sherman O.H., Banffy M.B. Anterior cruciate ligament reconstruction: which graft is best? Arthroscopy 2004; 20:974-80.

11. Herrington L., Wrapson C., Matthews M., Matthews H. Anterior cruciate ligament reconstruction, hamstring versus bone-patella tendon-bone grafts: a systematic literature review of outcome from surgery. Knee 2005; 12:41-50.

12. Forster M.C., Forster I.W. Patellar tendon or four-strand hamstring? A systematic review of autografts for anterior cruciate ligament reconstruction. Knee 2005; 12:225-30.

13. Biau D.J., Tournoux C., Katsahian S., Schranz P.J., Nizard R.S. Bone-patellar tendon-bone autografts versus hamstring autografts for reconstruction of anterior cruciate ligament: meta-analysis. Bmj 2006; 332:995-1001.

14. Yunes M., Richmond J.C., Engels E.A., Pinczewski L.A. Patellar versus hamstring tendons in anterior cruciate ligament reconstruction: A meta-analysis. Arthroscopy 2001; 17:248-257.

15. Goldblatt J.P., Fitzsimmons S.E., Balk E., Richmond J.C. Reconstruction of the anterior cruciate ligament: meta-analysis of patellar tendon versus hamstring tendon autograft. Arthroscopy 2005; 21:791-803.

16. Prodromos C.C., Joyce B.T., Shi K., Keller B.L. A meta-analysis of stability after anterior cruciate ligament reconstruction as a function of hamstring versus patellar tendon graft and fixation type. Arthroscopy 2005; 21:1202.

 

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