Choosing the right graft is an important part of ACL reconstruction. Two of the most established options are the bone-patellar tendon-bone (BPTB) graft, commonly called a patellar tendon graft, and the hamstring tendon graft.
Both have been used extensively and can provide good outcomes, but they differ in how the graft is obtained and the potential effects on the area from which it is taken.
There is no single graft that is automatically right for everyone. Your activity level, sporting goals, previous injuries or surgeries, knee characteristics, and concerns about donor-site symptoms can all influence the choice.
What Is the Difference Between the Two Grafts?
The main difference is where the replacement tissue comes from.
- Patellar tendon graft: Uses the central portion of the patellar tendon along with small bone plugs from the kneecap and shinbone. It is also known as a bone-patellar tendon-bone or BPTB graft.
- Hamstring graft: Uses one or more of the hamstring tendons from the back of the thigh. The tendon is prepared and folded to create the ACL graft.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Patellar Tendon Graft: What to Know
A BPTB graft has been a long-established option for ACL reconstruction. Because it contains bone plugs at each end, the graft can be secured within the bone tunnels created during reconstruction.
Potential advantages
- Extensive clinical experience with its use in ACL reconstruction.
- Bone-to-bone healing occurs at the graft fixation sites.
- It can provide reliable knee stability following reconstruction.
- It may be considered for people with high physical or sporting demands.
Potential drawbacks
The main consideration is the area from which the graft is harvested. Some patients experience pain at the front of the knee or discomfort when kneeling after surgery. This can be particularly relevant if your occupation, sport, or daily activities require frequent kneeling.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
A systematic review of long-term randomized studies found no significant difference in overall clinical outcomes or graft failure between patellar tendon and hamstring grafts, but kneeling pain was reported more often in some studies among patients with patellar tendon grafts.
Hamstring Graft: What to Know
A hamstring graft is obtained from tendons at the back of the thigh. The harvested tendon is prepared to create a graft suitable for ACL reconstruction.
Potential advantages
- Does not involve harvesting tissue from the patellar tendon.
- May result in less anterior knee and kneeling pain than a patellar tendon graft.
- Provides an established option for ACL reconstruction with extensive clinical experience.
Potential drawbacks
Because the graft is taken from the hamstring region, some patients may experience temporary weakness in the hamstring muscles. Rehabilitation therefore includes restoring strength and function in the harvested muscle group.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
The available tendon size can also vary between individuals, which is one of the factors considered when planning the reconstruction.
Patellar Tendon vs Hamstring Graft: Key Differences
| Factor | Patellar Tendon (BPTB) | Hamstring |
|---|---|---|
| Harvest site | Central portion of the patellar tendon | Tendons at the back of the thigh |
| Graft structure | Tendon with bone plugs | Soft-tissue tendon |
| Main donor-site concern | Anterior knee or kneeling pain | Hamstring weakness or discomfort |
| Knee stability | Good clinical outcomes reported | Good clinical outcomes reported |
| Graft failure | Generally low; evidence does not consistently show a major difference from hamstring grafts | Generally low; evidence does not consistently show a major difference from patellar tendon grafts |
| Kneeling discomfort | More likely to be a concern | Generally less of a concern |
Which Graft Has a Lower Risk of Failure?
Research has produced somewhat different findings depending on the population and study design. Some large analyses have found a small difference in graft rupture rates favoring BPTB grafts, while other systematic reviews have found no significant difference between BPTB and hamstring grafts.
More recent evidence focusing on athletes found no significant difference between the two graft types in return to sport, return to pre-injury activity level, or graft re-rupture rates.
Therefore, graft failure risk should not be considered in isolation. The overall clinical picture and the potential effects of graft harvesting also matter when choosing between the two.
What About Return to Sports?
Both graft types can be used in patients who want to return to sports. Research comparing BPTB and hamstring autografts has not consistently demonstrated a meaningful difference in overall return-to-sport rates or return to pre-injury activity levels.
However, returning to sport depends on much more than graft selection. Rehabilitation, restoration of strength, knee stability, movement quality, psychological readiness, and the demands of the particular sport all play important roles.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Which Graft Causes More Pain?
The type of pain matters when comparing these grafts. Patellar tendon grafts are particularly associated with donor-site symptoms around the front of the knee and discomfort while kneeling.
A systematic review of randomized studies reported a wide range of anterior knee and kneeling pain after BPTB ACL reconstruction, highlighting that the experience varies considerably between patients.
Hamstring grafts avoid harvesting tissue from the patellar tendon, so anterior knee and kneeling symptoms may be less of a concern. However, hamstring weakness or discomfort can occur and should be addressed during rehabilitation.
Who Might Prefer One Graft Over the Other?
Graft selection is individualized, but certain considerations may make one option more relevant than another.
A patellar tendon graft may be considered when:
- Strong fixation and the established BPTB technique are important considerations.
- You participate in activities involving substantial physical demands.
- You do not have significant concerns about kneeling discomfort.
- Your surgeon considers the patellar tendon an appropriate graft source for your knee.
A hamstring graft may be considered when:
- Avoiding patellar tendon harvesting is a priority.
- Your work or activities involve frequent kneeling.
- You have concerns about anterior knee pain.
- The hamstring tendons provide an appropriate graft for your reconstruction.
These are general considerations rather than rules. The same graft may be appropriate for one patient and less suitable for another.
The Bottom Line
Patellar tendon and hamstring grafts are both well-established choices for ACL reconstruction. Evidence suggests that both can provide good knee stability and functional outcomes, while differences are more noticeable in some donor-site effects.
A patellar tendon graft may be associated with a greater risk of anterior knee or kneeling pain, while a hamstring graft may involve more consideration of hamstring strength. Differences in graft failure and return to sport are generally not large or consistently demonstrated across studies.
The most appropriate graft is therefore the one that fits your individual knee, activity requirements, recovery priorities, and overall treatment plan.
