Anterior cruciate ligament injuries, commonly known as ACL injuries, are among the most common knee injuries in athletes and active individuals. The ACL helps stabilize the knee during movement, especially when cutting, pivoting, jumping, or changing direction. When this ligament is torn, many patients require anterior cruciate ligament reconstruction, or ACLR, to restore knee stability and support a return to activity.
Although ACL reconstruction is a well-established surgical procedure, recovery can still take several months and may involve pain, swelling, limited mobility, muscle weakness, and a gradual return to sports or exercise. Because of this, researchers continue to study supportive therapies that may help improve healing and recovery after surgery.
One area of interest is platelet-rich plasma, also known as PRP. In this systematic review and meta-analysis published in Frontiers in Bioengineering and Biotechnology, researchers evaluated whether PRP injections may improve recovery, pain, knee function, graft healing, and rehabilitation outcomes after ACL reconstruction.
What Is Platelet-Rich Plasma?
Platelet-rich plasma is prepared from a patient’s own blood. A blood sample is collected and processed to concentrate the platelets, which are small blood components involved in clotting and tissue repair.
Platelets contain growth factors, cytokines, and other signaling molecules that may help support healing. Because of these properties, PRP is commonly studied in orthopedic and sports medicine settings, including tendon injuries, ligament injuries, joint conditions, and postsurgical recovery.
In ACL reconstruction, PRP may be applied during surgery or injected after surgery to support the healing environment around the reconstructed ligament and surrounding tissues.
Researchers are interested in PRP because it may help:
- Reduce early postoperative pain
- Support tissue healing
- Encourage graft integration
- Influence inflammation
- Assist with rehabilitation progress
- Improve short-term knee function
Study Overview
This review analyzed randomized controlled trials from the past 15 years that studied PRP use in ACL reconstruction. The researchers searched major scientific databases, including PubMed, Embase, and Web of Science, and ultimately included 24 randomized controlled trials in the meta-analysis.
The review compared patients who received PRP during or after ACL reconstruction with patients who received control treatments or standard surgical care without PRP.
The researchers looked at several outcomes, including:
- Pain levels
- IKDC knee function scores
- Lysholm knee scores
- Tegner activity scores
- Knee stability measurements
- Graft maturation
- Complications
- Rehabilitation-related outcomes
By reviewing multiple studies together, the authors aimed to better understand where PRP may be most helpful and where results are less consistent.
Key Findings From the Review
The review found that PRP showed its clearest benefit in short-term pain relief after ACL reconstruction. Patients who received PRP had significantly better pain scores at 3 months after surgery, with continued benefit seen at 6 months in some analyses.
This is meaningful because pain control is an important part of early recovery. Less pain may help patients move more comfortably, participate in rehabilitation, and regain confidence during the healing process.
The review also found some improvements in knee function scores. For example, PRP was associated with improved IKDC scores at 12 months and improved Lysholm scores at certain follow-up points. These scores are commonly used to assess knee symptoms, function, and recovery after injury or surgery.
However, the results were not equally strong across every outcome. Some measures, such as activity level, graft maturation, and certain knee stability findings, did not show consistent differences between the PRP and control groups.
Overall, the study suggests that PRP may provide the most noticeable benefits during the earlier stages of recovery, especially for pain relief and some functional measures.
PRP and Postoperative Pain Relief
One of the most important findings from this review was PRP’s effect on pain after ACL reconstruction. The researchers found that patients who received PRP had significantly lower pain scores at 3 months after surgery compared with control groups.
This may be because PRP contains growth factors and signaling molecules that can influence inflammation and tissue repair. By supporting the healing environment, PRP may help reduce discomfort during the early recovery period.
For patients recovering from ACL reconstruction, this matters because early pain can affect:
- Walking comfort
- Range of motion
- Physical therapy participation
- Muscle activation
- Confidence with movement
- Overall rehabilitation progress
While PRP is not a replacement for structured rehabilitation, the findings suggest it may be a helpful supportive tool in the early recovery phase.
Effects on Knee Function
The review also examined knee function using validated scoring systems, including the IKDC and Lysholm scores. These tools help measure symptoms, stability, pain, function, and ability to return to activity.
The PRP group showed improvement in IKDC scores at 12 months and improvements in Lysholm scores at certain earlier follow-up points. This suggests that PRP may support functional recovery in some patients following ACL reconstruction.
However, the authors noted that some improvements did not always reach the level considered clinically meaningful across all measures. In simpler terms, while PRP showed encouraging trends in knee function, the size and consistency of the benefit varied across studies.
This is likely because the included studies used different PRP preparation methods, injection timing, graft types, doses, and follow-up schedules. These differences can make it harder to compare results directly.
Graft Healing and Knee Stability
Another area of interest was whether PRP could improve graft healing after ACL reconstruction. During ACLR, the torn ligament is replaced with a graft, which must gradually incorporate into the body and become part of the knee’s support structure.
PRP is being studied because its growth factors may help support tendon-bone healing, tissue remodeling, and graft integration. In theory, this could help improve recovery and long-term knee stability.
In this review, however, graft maturation and knee stability findings were mixed. Some measures showed favorable findings, but others did not demonstrate a clear difference between PRP and control groups.
This does not mean PRP has no role in ACL recovery. Rather, it suggests that PRP’s strongest evidence in this review was related to short-term pain relief, while its effects on graft maturation and long-term stability need more standardized research.
Safety and Tolerability
The review also looked at complications reported across the included studies. Many studies reported no PRP-related postoperative complications, and others found no significant complications such as infection, vascular injury, nerve injury, joint stiffness, excessive fluid buildup, or allergic reactions.
In studies that reported side effects, they were generally mild and temporary. Examples included injection-site pain or knee swelling that resolved within a few days.
These findings suggest that PRP was generally well tolerated in the studies reviewed. As with any medical procedure, careful technique, proper preparation, and appropriate patient selection remain important.
Why Standardization Matters
One of the biggest takeaways from this review is the need for more standardized PRP protocols. PRP is not always prepared the same way from one study or clinic to another. Differences may include platelet concentration, centrifugation method, injection timing, number of injections, injection location, and whether PRP is used during or after surgery.
These differences can affect results and make it harder to know which PRP approach works best.
Future research may help clarify:
- Ideal PRP concentration
- Best timing for PRP application
- Whether one or multiple injections are more useful
- Which graft types respond best
- Which patients may benefit most
- How PRP affects long-term recovery
- Whether PRP improves return-to-sport outcomes
This kind of research will help refine how PRP is used in ACL reconstruction and orthopedic recovery.
Why This Research Matters
ACL reconstruction is often a major recovery process, especially for athletes and active individuals who want to return to sport or regular exercise. Any supportive therapy that may help reduce pain, improve comfort, and support rehabilitation is worth studying carefully.
This review suggests that PRP may offer benefits during the early recovery period, especially when it comes to pain relief. It may also support certain functional improvements, although long-term outcomes such as graft maturation and knee stability remain less consistent across studies.
For regenerative medicine and sports recovery, this study adds to the growing understanding of how PRP may be used as part of a broader healing strategy. PRP is not presented as a standalone solution, but as a potential supportive therapy that may complement surgery, rehabilitation, and proper recovery planning.
A Promising Supportive Tool in Orthopedic Recovery
Platelet-rich plasma continues to be an important area of research in orthopedic and regenerative medicine. Its ability to deliver concentrated growth factors and healing signals makes it especially interesting for ligament injuries and postsurgical recovery.
This systematic review found that PRP application during or after ACL reconstruction may help reduce short-term pain and support certain functional outcomes. While more research is needed to better define ideal treatment protocols, PRP remains a promising supportive tool in the recovery process.
As future studies continue to refine preparation methods, dosing, timing, and patient selection, PRP may become an increasingly useful part of personalized orthopedic and sports medicine care.
Source Zhang Y, Xiao Z, Fan Z, Zhang Y, Xu J, Wang K. The impact of platelet-rich plasma injection on anterior cruciate ligament reconstruction: a systematic review and meta-analysis. Front Bioeng Biotechnol. 2025 Oct 1;13:1625271. doi: 10.3389/fbioe.2025.1625271. Available from: https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2025.1625271/full