Paul H. Wright, M.D., FRCSC
Clinical Associate Professor
U.B.C.
Burnaby, BC

The use of the Patellar Tendon Autograft (PTA), or a four strand Hamstring Autograft (HA) results in a similar surgical outcome at five years¹. Both grafts are excellent choices for stability.  

Patient Morbidity
Having used both graft sources over 20 years of knee reconstruction, I now use the HA whenever possible for a single reason: decreased patient morbidity.

Comparison of Studies
Most studies fail to compare the grafts equally. It is only fair to compare the grafts using modern fixation techniques. This involves fixing both types of grafts to the bone at the intra-articular aperture. Grafts fixed externally to the bone tunnel, or by non anatomic suspension methods do not offer valid comparison². Beyonnon and Johnson found comparable results in terms of patient satisfaction, activity level and knee function at three years. This study in the JBJS found the PTA to be more stable at three years but compared a two-strand technique fixed externally. Fowler has shown that a doubled Semitendinosis graft is as strong as a four-strand graft, clinically. The difference was that a more stable fixation technique was employed³.

Pinczewski et al. offer the first five-year follow-up to accurately compare the two graft sources in a controlled fashion¹.

Incorporation into the Tunnels
Both grafts incorporate into the intended tunnels. The HA forms collagenous crosslinks with the host femoral bone^3,4. Both offer adequate fixation to allow an early rehabilitation programme⁵.

Donor Site Morbidity: Kneeling Problems
Kneeling is frequently not possible in the PTA group for sport or work. In contrast, the hamstring group is able to engage in prolonged kneeling activity. This is significant for many people and may guide you in your choice of grafts^1,6,7. Corey has reported that 6% of patients undergoing HA had pain on kneeling after two years. The PTA group reported a 31% rate of pain.

Disturbance of Sensitivity
Both graft choices can disturb the sensitivity of the knee region. This can be responsible for kneeling pain and knee walking difficulties.

The more distally located area of disturbed sensitivity with HA imparts less disability8.

Pain at Rest
If followed out to five years, 41% of the PTA group reported donor site symptoms at rest. This compares to 12% in the HA group¹. Early in rehabilitation, the HA group has less pain from the graft site, which can lead to a more rapid rehabilitation with less tendency to develop knee stiffness.

Hamstring Function
Numerous studies have shown excellent hamstring function 18 months after the use of the HA. It must be remembered that the primary function of the Hamstring complex is that of a Hip Extensor. Patients requiring specific hip extensor control should be counselled in the choice of grafts so they can weigh this deficiency against the increased morbidity of kneeling and donor site with the PTA. Specific hip extension deficits have not been well studied to date.

Pre-existing Patellar Pain
The risk of worsening pre-injury patellar pain and dysfunction is greater in the PTA group. Both groups can experience an increase in patellar symptoms after knee reconstruction; the risk to the patient is higher with PTA. This can lead to a condition worse than an unstable knee. Be aware of this problem. The patient often downplays the symptoms when overshadowed by a recent ligament injury. Variable reporting by the patients often confuses anterior knee pain with the feeling of "stiffness". This is very subjective, but is reported more often in the PTA group². Beynnon found a stiffness rate at two years of 55% in PTA and 27% in HA.

Knee Range of Motion and Osteoarthritis
Loss of motion with time in the PTA group may reflect the gradual onset of patellar arthritis. The radiological findings at five years support an increase in the appearance of arthritis in PTA group by IKDC criteria (B and C-PTA 18%, HA 4%)1. Pinczewski also has documented an increase in the presence of flexion contractures over time in the PTA group. This has not been observed in those receiving an HA.

Your Decision for Graft Choice
Long-term laxity trials are demonstrating equal laxity measurements at five-year follow-up. The use of the Hamstring Tendons offers fewer donor-site problems, making it the superior choice for your patients.

My biggest concern with the PTA is the increasing rate of osteoarthritis. I have long felt that it will be the "Putti-Platt" of the knee, offering long-term stability with increased osteoarthritis.

References

1. Pinczewski L., Deeham D, et al.: A Five Year Comparison of Patellar Tendon Versus Four Strand Hamstring Tendon Autograft for Arthroscopic Reconstruction of the Anterior Cruciate Ligament. Am J Sport Med 30: 523-536,2002.
   
   
2. Beynnon B., Johnson R., et al.: Anterior Cruciate Ligament Replacement: Comparison of Bon-Patellar Tendon-Bone Grafts with Two Stranded Hamstring Grafts. J Bone Joint Surg Am 84-A: 1503-1513, 2002.
   
   
3. Frank C., Jackson D.: The science of reconstruction of the Anterior Cruciate Ligament. J Bone Joint Surg Am 79A: 1556-1576, 1997.
   
   
4. Pinczewski L., Clingeleffer A., et al.: Integration of Hamstring tendon graft with bone in reconstruction of the anterior Cruciate ligament. Arthroscopy 13: 641-643, 1997.
   
   
5. Corry I., Webb J., et al.: Arthroscopic Reconstruction of the Anterior Cruciate Ligament. A comparison of Patellar Tendon Autograft and four-stranded hamstring tendon Autograft. Am J Sport Med 27: 444-454, 1999.
   
   
6. Aglietti P., Buzzi R., et al.: Patellofemoral problems after intraarticular anterior Cruciate ligament reconstruction. Clin Ortho 288: 195-203, 1993.
   
   
7. Kartus J., Movin T., et al.: Donor-Site Morbidity and Anterior Knee Problems after Anterior Cruciate Ligament Reconstruction Using Autografts. Arthroscopy17:971-980, 2001.
   
   
8. Eriksson K.: On the Semitendinosus in anterior Cruciate ligament reconstructive surgery. Thesis, Karolinska Institute, Stockholm, Sweden, 2001.