Outcomes of Ipsilateral Versus Contralateral Bone–Patellar Tendon–Bone (BPTB) Autografts in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis
This systematic review and meta-analysis of 6,631 participants indicates that while contralateral bone–patellar tendon–bone autografts for primary ACL reconstruction do not significantly differ from ipsilateral grafts in clinical, strength, or morbidity outcomes, they are associated with a significantly earlier return to sport.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
When a runner tears the ligament that stabilizes the knee, the path back to the field usually involves surgery to replace the torn tissue with a graft. Surgeons often choose a piece of the patient's own tendon from the kneecap area, known as a bone–patellar tendon–bone graft, because it is strong and heals reliably. However, taking this tissue creates a new injury at the harvest site, often causing pain when kneeling or weakness in the thigh muscles. For decades, the standard practice has been to take this graft from the same injured knee that needs fixing. This approach keeps the surgery focused on one leg, but it also means the patient must heal from two major injuries—the torn ligament and the harvested tendon—on the same limb simultaneously. This dual burden can slow down the critical early stages of rehabilitation, where rebuilding strength is essential. A different strategy has been proposed: taking the graft from the healthy, uninjured knee instead. The theory is that this spreads the recovery work across both legs, allowing the injured knee to focus entirely on regaining motion and stability while the healthy knee handles the healing of the donor site.
A team of researchers set out to determine if this alternative approach actually helps athletes return to their sports faster without causing new problems. They gathered and analyzed data from seven different studies involving more than 6,600 people who had undergone this specific type of knee reconstruction. The researchers compared patients who received their graft from the injured knee against those who received it from the opposite, healthy knee. They looked at how well the knees felt, how stable they were, how strong the leg muscles became, and how long it took for the athletes to get back to their games. They also carefully checked for complications, such as infections, re-tears of the new ligament, or pain in the knee where the tendon was taken.
The analysis revealed a clear advantage for the group that had the graft taken from the healthy knee. These athletes returned to their sports significantly sooner, with the data showing they were back on the field nearly one month earlier on average than those who had the graft taken from their injured leg. This finding suggests that splitting the recovery between two legs allows for a more efficient rehabilitation process. However, the study also found that this speed came without a trade-off in safety or long-term function. The researchers observed no meaningful difference between the two groups regarding how stable the knee felt, how well the patients rated their own pain and function, or how strong their leg muscles became in the long run. Both groups achieved similar levels of knee stability and strength recovery over time.
Regarding the risks, the study found that taking the graft from the healthy knee did not increase the likelihood of the new ligament failing or the knee becoming infected. The rates of these serious complications were nearly identical for both groups. The researchers also examined the pain and discomfort at the site where the tendon was harvested. While taking the tendon does cause some temporary pain and weakness, the data showed that the level of long-term trouble was comparable whether the graft came from the injured leg or the healthy one. The healthy knee did not suffer more severe or lasting damage than the injured knee did when it served as the donor.
These findings suggest that for high-demand athletes, harvesting the graft from the opposite, uninjured knee is a viable and effective option. It appears to offer a tangible benefit in the speed of recovery, allowing players to return to competition sooner, while maintaining the same high standards of knee stability and safety as the traditional method. The study does not claim this approach is perfect for every single patient, and it notes that more large-scale research is needed to confirm these results across different surgical centers. However, the evidence gathered so far indicates that surgeons can confidently offer this alternative to patients who prioritize a faster return to sport, knowing that it does not compromise the final outcome of the surgery.
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