February 09, 2026
9 min read
Key takeaways:
Table of Contents
- Historically, combined ACL and MCL injuries were often treated with open surgical approaches with much resultant stiffness.
- Today, surgeons have better operative and nonoperative options at their disposal.
In the 1970s and 1980s, combined ACL and grade 3 medial collateral ligament injuries were primarily treated with big, open surgical procedures.
“It was terrible,” Andy Williams, MBBS, FRCS(Ortho), FFSEM(UK), consultant knee surgeon at Fortius Clinic in London, told Healio. “Because we did not understand the anatomy, we cobbled it all together and, therefore, the structures we had repaired were not at the right length. You tended to end up with a knee that would not straighten and would not bend, but the MCL remained loose. It was the worst of all worlds.”
Source: Jelle P. van der List, MD, PhD, MBA
However, as technology improved, surgeons began to move away from open approaches to fix the ligaments, according to Gregory S. DiFelice, MD, orthopedic surgeon at Hospital for Special Surgery.
Gregory S. DiFelice
“MRI came around, which allowed us to take a look and see not only if the ligament was torn, but also how the ligament was torn,” DiFelice said. “Before we had MRIs, the only way we could tell how the ligament was torn was to open up the knee. Whereas now, we have this diagnostic tool that assists us in understanding the injury patterns and damage to the anatomic structures we are trying to restore.”
In addition, DiFelice said the introduction of arthroscopy allowed surgeons to make small incisions and use the arthroscope to look inside the knee and assess the damage before deciding how to proceed.
By the 1990s, given the stiffness that results from open procedures, Williams said the pendulum had swung to nonoperative treatment of the MCL.
Andy Williams
“It became clear that it would be better not to touch the MCL,” Williams said. “The dogma was to treat in a brace for 6 weeks, with or without the ACL injury, and then you would go to surgery from 6 weeks for the ACL. That held sway for a long time, and that led to the notion that the MCL takes care of itself.”
Modern day
Today, the treatment of combined ACL and MCL injuries is more complicated and less dogmatic, according to Jelle P. van der ListMDPhD, MBA, clinical assistant professor of orthopedic surgery at The Ohio State University Wexner Medical Center.
Source: van der List JP, et al. Am J Sports Med. 2026;doi:10.1177/03635465251371330.
A systematic review published by van der List and colleagues in Arthroscopy showed that nonoperative ACL-MCL treatment and acute MCL repair with nonoperative ACL treatment yielded low rates of valgus stability at 30° of knee flexion when compared with acute ACL reconstruction with either nonoperative MCL, acute MCL repair or acute MCL reconstruction.
“The problem is, if you have a combined ACL-MCL injury and you try to let the MCL heal in a brace, the tibia still keeps moving forward,” van der List told Healio. “Because of that, there is no isometry of the MCL to heal. Even though you put the knee in a hinged brace and the MCL cannot stretch sideways, it can still not heal isometrically because of the anterior-posterior translation. That is the biggest problem of treating ACL-MCL injuries nonoperatively first because the MCL does not heal with satisfaction. There is residual laxity. We are now starting to understand that this treatment algorithm of initial nonoperative treatment with delayed ACL reconstruction has disadvantages.”
Technical advances have driven the procedure forward and given modern orthopedic surgeons a plethora of tools at their disposal, according to Matthew T. ProvencherMDMBA, professor of orthopedics and orthopedic surgeon at The Steadman Clinic.
Matthew T. Provencher
“With better understanding of the anatomy, better repair techniques, better anchor techniques, better sutures, better ways to anatomically augment collagen and better ways to use the internal brace, we have been able to minimize arthrofibrosis, yet restore the mechanics of the knee, especially with the MCL,” Provencher said. “That helps with preventing excessive internal and external rotation, which will put a lot of force across the ACL graft.”
Acute simultaneous treatment
With modern advances in technology and techniques, many surgeons now perform acute simultaneous surgery of both the ACL and MCL when indications allow, according to DiFelice. He said patients with significant laxity in both the ACL and MCL may benefit from a repair procedure on both ligaments.
In a retrospective analysis, DiFelice and colleagues found 90% of 20 patients with a grade 3 superficial MCL injury and additional cruciate or bicruciate ligament injury who underwent acute superficial MCL repair and an early range of motion rehabilitation protocol experienced negative valgus laxity stress testing in 0° and 30° of flexion and low rates of reoperation due to stiffness.
“With this less invasive, thoughtful, pragmatic and logical approach, we can help people to recover in a fraction of the time with a fraction of the morbidity and the complications that they would experience if they do it the old-fashioned way,” DiFelice said.
However, Williams said surgeons “have to be sensible” when it comes to treating ACL-MCL injuries. For most combined ACL-MCL injuries in an average patient, Williams said he would have the patient wear a brace for 4 to 6 weeks, making sure the knee can be made fully straight as well as perform a full bend. After 12 weeks, the knee is reexamined and patients who need surgery for their ACL will also undergo surgery of the MCL if they have grade 2 or 3 valgus laxity or a positive dial or Slocum test, according to Williams.
But high-level or professional athletes require a different set of expectations and treatment considerations, Williams said.
“Professional soccer players do not tolerate MCL laxity well because they are changing direction a lot and cutting off that leg, and the MCL is really important,” Williams said. “They are not going to wait 12 weeks for surgery, so I have to make a call straight away. I am so confident in modern surgery, and I am lucky that I have a bunch of very tough people who get the best physiotherapy, that I fix them all. I do not accept any laxity. Even if I get a grade 1 MCL, I go for it. And that does mean I am possibly overtreating, but the stakes are very high in pro sport.”
Tear location
A major factor in the decision to perform acute simultaneous treatment is often tear location, according to R. Alexander CreightonMD, Yeargan Professor and chief of sports medicine at UNC Orthopedics. For example, Creighton said proximal injuries may heal better than distal injuries. A distal MCL injury may also have a Stener-like lesion, which Creighton said involves displacement of the MCL superficial to the Pes Anserine hamstring tendons. He said this type of injury will not heal on its own and needs a more aggressive repair.
However, it is not only the location that can be a problem, but also the timing.
R. Alexander Creighton
“The problem with [performing ACL reconstruction] 3 weeks out is sometimes the patient’s motion is not very good,” Creighton said. “You must get their motion back before you do a big surgery on them. I was taught you come out of that surgery as you go into it. If you can get to them acutely, you can sometimes do both. But if it is in that gray area of 2 to 3 weeks, you are probably better off waiting until you get to 4 to 6 weeks and get their motion back.”
For that reason, operating on the ACL both acutely and early is paramount, according to van der List.
In a systematic review and meta-analysis published in the American Journal of Sports Medicinevan der List and colleagues found that a shorter time from injury to ACL reconstruction was associated with a decreased incidence of long-term osteoarthritis. According to the study, the reduced risk was most pronounced when surgery was performed within 6 and 12 months, but this effect was already seen when performing ACL surgery within 1 month compared with later than 1 month.
“When you treat the ACL in the more acute setting, it does not matter what you do to the MCL,” van der List said. “You can even consider treating the MCL nonoperatively by immobilizing it postoperatively in a hinged knee brace, and it will heal. This is because there is no isometry and you have converted a combined ACL-MCL into an isolated MCL injury, of which we know heal well without surgery and without residual laxity. Once you are there, treating the ACL early and repairing the MCL allows them to do range of motion a little bit earlier. They do not need a knee hinge brace. But I do not think it matters that much if you repair some of the MCLs vs. treat it nonoperatively as long as you treat the ACL early.”
He added, “There are always nuances. Tear location is really important… and, of course, sport and other activity timelines. But, in general, I do not think that we need to treat the MCL acutely. I think we need to treat the ACL acutely. We now see that with recent NFL injuries in which multiligamentous knee injuries are treated within 24 hours.”
Risks
But acute simultaneous treatment of combined ACL and grade 3 MCL injuries does not come without its own risks and complications, according to van der List.
“The biggest risk is stiffness,” van der List said. “If you talk about who is at risk for getting stiff, studies show it is patients with proximal MCL tears in combination with ACL tears in people who are fearful.”
To avoid knee stiffness, Provencher said it is important for surgeons to remember not to “do too much” to treat an ACL-MCL injury.
“We have to be cognizant of what was taught to us for many years and be careful not to overdo this but to thread the needle, in a way,” Provencher said. “We know that we need these ligaments to act in synergy together because they are additive, but we have to be careful not to get knee stiffness because that is a tough complication to deal with.”
Augmentation
During surgical treatment of ACL-MCL injuries, some surgeons have also started to augment their repairs with collagen-based implants, suture augmentation or grafts, according to DiFelice.
However, van der List said the indications of biologic augmentation have not “been clear on when it is beneficial.” While biologics can be beneficial in meniscus injuries, he said there is a lot of healing in ACL reconstructions and MCL reconstruction and repair without augmentation that “there are not a lot of reasons to do it.”
“I do not think there is a lot of evidence to adding biology to a standard ACL reconstruction or that an MCL repair or MCL reconstruction will really benefit,” van der List said. “There are no studies looking at just treating these injuries with biologics and seeing if they heal right. This is different for augmentation with grafts or suture augmentation. Evidence is increasingly showing a benefit for those.”
However, Creighton said the use of augments to treat ACL-MCL injuries sometimes provides the surgeon with comfort and reassurance.
“You want it to heal, so sometimes it makes you feel better to put an augment on top of the repair if their tendon is beat up,” Creighton said. “But that is also one where maybe you should consider reconstruction, and I am not sure we know the true answer to that.”
Future
The best way to improve level of evidence recommendations for different tear types in and treatments for ACL-MCL injuries is by obtaining more patient numbers in clinical outcomes, according to Provencher.
“The only way we are going to be able to do that is with a multicenter study looking at the ACL and MCL together and how these are treated and how they turn out so we can continue to improve this important topic,” Provencher said. “At the end of the day, you want to get it right for the patient the first time so they have a stable, well-functioning knee.”
In addition to more clinical follow-up, Williams said it is important to test the various reconstruction strategies that are published in a cadaver lab.
“There are limitations to lab testing because it is time zero when you put something in the lab and test it, and the human body will stretch out and things happen with healing,” Williams said. “But it is a good place to start.”
As researchers and surgeons continue to refine techniques and discover nuances to treatment options, Williams said they “have a strong duty to educate the general surgeon population.”
Not only should surgeons educate surgeons, but they should also educate patients on the pros and cons of undergoing surgery early vs. late, according to Creighton.
“Losing range of motion after surgery is a big deal and tough to get back,” Creighton said. “I have traditionally erred on the side of being a little more conservative and trying to get their motion back before we do a surgery, but, again, that distal MCL does not heal as well. I am more aggressive with treating those patients. It is important to educate the patient that not all MCL injuries are the same.”
For more information:
R. Alexander CreightonMD, can be contacted at alex_creighton@med.unc.edu.
Gregory S. DiFelice, MD, wishes to be contacted through mediarelations@hss.edu.
Matthew T. ProvencherMDMBA, can be contacted at mprovencher@thesteadmanclinic.com.
Jelle P. van der ListMDPhD, MBA, can be contacted at jelle.vanderlist@osumc.edu.
Andy Williams, MBBS, FRCS(Ortho), FFSEM(UK), can be contacted at williams@fortiusclinic.com.
Sources/Disclosures
Source:
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References:
Disclosures:
DiFelice reports receiving support from Miach Orthopedics, Osteo Remedies and Zimmer Biomet; and having stock or stock options in Zimmer Biomet. Provencher reports receiving consulting fees from Arthrex and JRF Ortho. Williams reports having stock or stock options in Innovate Orthopaedics; being an editorial board member for the American Journal of Sports Medicine; receiving research funding from Smith & Nephew; and running fellowships with Smith & Nephew. Creighton and van der List report no relevant financial disclosures.
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