After ACL Reconstruction: Complication and post-surgery treatment options: Do you need revision surgery?

Ross Hauser, MD, Danielle R. Steilen-Matias, MMS, PA-C

In this article, we will discuss problems of knee instability following anterior cruciate ligament reconstruction surgery and review various non-surgical or revision treatment suggestions to stabilize the unstable post-ACL surgical knee.

ACL reconstructive surgery works for many patients. But how do we define the definition of “works?” Was the surgery successful but does your knee still feel like it could give way? Maybe your knee bends backward a little further than you think it should. If so, was your surgery then really that successful?

  • Maybe you did have a successful surgery, however, as you are reading this article you are likely researching problems of an unstable knee that is preventing you from doing sports, work, or other daily routines.
  • For some of you, it is likely that if you are reading this article, you had a less than successful surgery, your knee is very unstable and you are looking for answers that go beyond buying one knee brace after another.

Many patients that we see following an anterior cruciate ligament reconstruction surgery are confused. They thought for sure once they had the ACL surgery that they would be back to doing what they were doing with the same, if not better, knee than they had before the surgery. This is despite the fact that their surgeon probably advised them of possible post-surgery problems, such as instability and the need for extensive rehabilitation.

Other patients recognized immediately that their surgery did not go that well. In immediate post-op rehabilitation, they suffered and may continue to suffer from post-surgical complications. They too are looking for answers beyond knee braces, extended physical therapy, painkillers, and the constant reminders from their health care providers that knee replacement will likely be the ultimate solution down the road.

Discussion points of this article

  • When the other knee ligaments are too weak to support the new ACL, this causes ACL surgery failure.
  • The appeal and enthusiasm for ACL reconstruction surgery, is this misguided?
    • A patient will say: “What other choice did I have, BUT to get the surgery?”
  • I had a successful ACL surgery, but I gave up my sports anyway.
  • Ten years later – still looking for explanations as to why many people need a second ACL reconstruction surgery.
  • The second ACL surgery or “revision surgery” is a very popular procedure. It is also much less “successful.” Especially for the adolescent athlete.
  • Patients can expect a 70% return-to-sport within seven years after ACL Reconstruction.
  • The younger hamstring graft is too stiff – Younger patients have worse surgical outcomes.
  • Why do doctors want to avoid a revision surgery – for one it’s the inferior results.
  • The more revision surgeries, the fewer sports.
  • Now let’s talk about the meniscus – “Meniscus tears seen at the time of anterior cruciate ligament reconstruction are usually asymptomatic.”
  • Avoiding “Revision – Revision” – the Third ACL surgery – Back in the tunnels.
  • Multiple studies have shown that the rate of return to the pre-injury level of sport is significantly lower following revision ACLR than following primary ACLR procedures.
    • The young athlete’s knee is not the same after ACL reconstruction.
  • Ten years later, my knee is still not the same.
  • Does ACL reconstruction prevent posttraumatic osteoarthritis?
    • ACL reconstruction and the development of posttraumatic osteoarthritis.
    • The fact that your knee is moving towards inevitable knee replacement should tell you that every day your knee is getting weaker.
  • Many people have issues with knee instability and function after anterior cruciate ligament reconstruction, it is not just you.
  • What if I buy a really good brace? Study: Knee bracing does not appear to improve the clinical outcomes on the function and stability of ACL-reconstructed knees.
  • Does hyaluronic acid injections help with swelling and joint stiffness after ACL reconstruction?
  • It is time to talk about the other ligaments of the knee – When the other knee ligaments are too weak to support the new ACL, this causes ACL surgery failure.
  • Study: “Generalized Hypermobility, Knee Hyperextension, and Outcomes After Anterior Cruciate Ligament Reconstruction”
  • “Preoperative laxity of the knee” and “Excessive graft laxity” as a cause of ACL surgery failure.
  • The prevalence of knee hyperextension (knee instability) in ACL revision surgery patients.
  • “Revision anterior cruciate ligament reconstruction restores knee laxity but shows inferior functional knee outcome.
  • “Preoperative medial knee instability is an underestimated risk factor for revision ACLR failure.”
  • “In spite of supposedly successful surgery, slight residual knee laxity may be found at follow-up evaluations after anterior cruciate ligament reconstruction (ACLR), and its clinical effect is undetermined.”
  • The road to preventing ACL revision surgery – ligament strengthening.
  • The regenerative approach to Knee ligament weakness and degenerative injury.

I had a successful ACL surgery, but I gave up my sports anyway

Later in this article, we will discuss making ACL surgery outcomes more successful with various non-surgical options.

One of the problems we see in many people who reach out to us is unrealistic expectations of what the surgery will do for them. Watching professional athletes return from “career-threatening,” ACL injuries is somewhat normal. So is that what a non-professional athlete should expect?

In 2014 surgeons wrote in the journal International Orthopaedics: (1) “the revision ACL reconstruction procedure offers improvement in subjective and objective outcomes. Lack of improvement in sports participation was noted in non-professional athletes and patients who downgraded their sports participation opting for non-contact sports.”

You may think that that study was in 2014, things must have improved by now. In a sense, you may think they went backward.

ACL reconstruction surgery

Ten years later – still looking for explanations as to why many people need a second ACL reconstruction surgery

A May 2020 study in The Journal of Knee Surgery (2) which was then updated in print in September 2021 went looking for answers by way of what doctors and researchers were looking up in the National Institutes of Health’s Library at PubMed.gov to explain why: “The rate of anterior cruciate ligament re-tear remains high and revision ACL reconstruction has worse outcomes compared with primaries.

What paper did the surgeons overwhelmingly refer to? A 2010 study titled: “Biomechanical Measures During Landing and Postural Stability Predict Second Anterior Cruciate Ligament Injury After Anterior Cruciate Ligament Reconstruction and Return to Sport“(3) What did this paper say?

“The findings of the current study support the tested hypothesis that altered neuromuscular control patterns during landing and deficits in postural stability predict subsequent ACL injuries in a sample of athletes at the time of return to sport after initial ACLR. Specifically, transverse plane net moment impulse at the hip, dynamic frontal plane knee range of motion, side-to-side differences in sagittal plane knee moment at initial contact, and deficits in postural stability predicted a second ACL injury with both high sensitivity and specificity.”

In other words, knee instability that impacted everything from hip to foot, when present, is a high risk for a second ACL rupture. Preventing this knee instability, as we will discuss below, is paramount to preventing the second ACL rupture.

The second ACL surgery or “revision surgery” is a very popular procedure. It is also much less “successful.” Especially for the adolescent athlete

You are a young athlete, you are the parent of a young athlete, the clock is always ticking because a young athlete’s career is finite in years. There is a great sense of urgency to get the knee repaired ASAP. So the appeal to revision surgery is very strong.

We are going to take a little research journey. The purpose is to demonstrate how surgeons for the last 10 years have struggled with ACL revision surgery.

2012:

  • Doctors writing in the American Journal of Sports Medicine (4) suggest that younger patients had a higher risk of revision ACL reconstruction than older patients and that subjective clinical outcome was worse after revision ACL reconstruction compared to primary ACL reconstruction.
    • Even though the second surgery was performed to fix the first surgery. You still had a high risk of being worse off after the second surgery.
    • They report that nearly 9% of patients under 20 need a second anterior cruciate ligament (ACL) Reconstruction Therapy.
  • Doctors reporting in the journal Clinical Orthopaedics and Related Research (5) also suggest that young, active, skeletally mature patients have higher failure rates after various surgical procedures, including primary ACL reconstruction.
    • While a single-stage transosseous revision (ACL tunnel repair surgery) restores knee stability, only 52% of these patients return to their prior level of activity or sport.

2020:

Surgeons at the University of California San Francisco issued these observations in the journal Current Reviews in Musculoskeletal Medicine. (6)

  • With an increase in high-demand sporting activity, the rate of pediatric and adolescent ACL reconstruction is increasing. Yet, the failure rates after reconstruction are much higher than the adult population.
  • An understanding of the ACL surgery failure should begin with:
    • an assessment of post-operative patient compliance and sporting activity. (Is the patient getting apportionment rehab following the surgery to begin competing again?)
    • Is it poor tunnel placement and poor graft size/type?
    • Concurrent bony deformity must also be addressed including lower extremity valgus alignment and tibial slope abnormalities. (Was the anatomical alignment of the ACL reconstruction correct or did the surgery itself create a misalignment?)
    • Meniscus and chondral injury must be aggressively treated.
    • Furthermore, imaging must be examined to look for missed posterolateral corner injuries. (There is much more damage to the knee beyond the ACL tear in the posterolateral corner of the knee. This includes:
      • lateral collateral ligament (LCL)
      • popliteus tendon
      • popliteofibular ligament
      • meniscofemoral and meniscotibial ligaments
      • the biceps femoris
      • the iliotibial band (ITB)
      • among other structures.

Tunnel placement complications

ACL tunnel complications
Image: Erickson B, et al. ORTHOPEDICS. 2016; 39: e456-e464.

If you had ACL surgery, you likely know all about tunnels. This is a significant complication of ACL reconstruction. As we are looking for solutions to your problem in this article we will only touch on this briefly. Tunnel problems are one of the problems where revision surgery is most likely warranted.

  • Tunnel widening (the hole gets bigger),
    • tunnel misplacement (the tunnel was put in the wrong place),
    • and fracture (the tunnel hole was too wide and caused a fracture of the bone) are the more common complications.

During the ACL reconstruction surgery, a hole is drilled in the thigh bone and the shin bone, the donor tendon that is being used as the graft is then threaded through the holes, through the knee, and fixed or screwed into place.

A March 2022 study from the Department of Orthopaedic Surgery, Division of Sports Medicine, Midwest Orthopaedics at Rush, Rush University Medical Center was published in the journal Arthroscopy (34) What this study suggested was that patients follow three different rate of Anterior Cruciate Ligament Reconstruction recovery patterns.

  • In this study, 245 patients who underwent primary or revision ACLR were divided into classes.
    • Class 1, were patients who had improvement from preoperative to one-year follow-up, with sustained improvement from one-to-two-years postoperatively. This class consisted of 77.1% of the study population (189 patients),
    • Class 2, were patients who demonstrated functional improvement between 1-and 2-year follow-up, and consisted of 10.2% (25 patients), and
    • Class 3, demonstrated slight improvement at 1-year follow-up with a subsequent decline in International Knee Documentation Committee (IKDC Questionnaire) scores between 1-and 2-year follow-up, consisted of 12.7% (31 patients) of the study population.

Patients can expect a 70% return-to-sport within seven years after ACL Reconstruction

A January 2022 study (27) in The American Journal of Sports Medicine discussed long-term patient-reported rates of return to sport and revision risk after ACL reconstruction.

There were 1045  reported patient outcomes in this study:

  • Autografts were used in 76% of the patients (patellar tendon, 62%; hamstring grafts, 38%).
  • Allografts were used in 24% of patients.
  • Patients were surveyed on average 7.2 years after their ACL reconstruction surgery.
  • Improvements were recorded in most patients’ knees.
  • The strongest predictor for lesser improvement was cartilage damage identified during the ACL reconstruction surgery. Meniscal lesions did not predict failure or complication of surgery
  • A total of 69% of patients had returned to the sport after 8.1 years (range, 6.7-9.8 years).
  • The main reason for not returning to sport was fear of reinjury.
  • The revision rate was 7.2% after 9 years (range, 8-11 years), 13% of patients needed subsequent ipsilateral (same side) non-ACL surgery, and 6% underwent contralateral (other side) ACL reconstruction surgery.
  • The absence of a meniscal tear, younger age, and male sex were predictors for (greater chance) for revision.
  • Graft choice did not predict patient-reported outcome results or revision risk.
  • Conclusion: There is a 26% chance of subsequent knee surgery within 9 years, including a revision rate of 7%, subsequent non-ACL surgery to the operated knee in 13%, and a 6% chance of contralateral ACL reconstruction surgery.

Why do doctors want to avoid a revision surgery – for one its the inferior results

2013: Why doctors want to avoid a revision was pointed out in a study out of Norway in the journal Knee Surgery, Sports Traumatology, Arthroscopy: (7)

  • Researchers compared 56 patients undergoing a revision reconstruction (the surgery after the first ACL surgery) to 52 patients undergoing primary reconstruction surgery, (the first surgery),
  • The results showed that the patients who had the second surgery had inferior results in almost every category of observation, including greater laxity, less muscle strength, and more severe radiological osteoarthritis.

August 2020: In the medical journal Orthopaedic Surgery (8), orthopedic surgeons published their findings and observations on possible inferior results achieved in revision or second ACL reconstruction surgery. Here are the summary learning points:

  • “More revisionary reconstruction procedures are required following failing anterior cruciate ligament (ACL) reconstructions, which are often regarded as a technical challenge with very limited goals.”
  • “Revision ACL reconstruction  could provide patients with excellent restoration of knee outcomes compared to the status before revision.” Comment: It is possible the second surgery can improve the knee function after the first attempt failed
  • “Also, while knee function in the revision group was inferior to the primary group, knee stability was equivalent between the two groups at the final follow-up.’ Comment: The first failed surgery and the revision surgery provided equal knee stability, despite the second surgery being inferior in helping function.

The more revision surgeries, the fewer sports

The Department of Orthopedic Surgery at the Mayo Clinic published findings in the American Journal of Sports Medicine. (9) Here they write: “Continuously increasing numbers of primary anterior cruciate ligament reconstructions invites a parallel increase in graft failures and need for revision ACL reconstruction surgery. High failure rates have previously stigmatized the revision surgery. . . Good outcomes of revision ACL reconstruction surgery are achievable. The use of different graft types did not affect the outcome of the procedure. Most of the patients opted for less aggressive sports participation after the revision procedure.”

The appeal and enthusiasm for ACL reconstruction surgery, is this misguided?
A patient will say: “What other choice did I have, BUT to get the surgery?”

Many times we will see a patient following anterior cruciate ligament reconstruction. To these patients we ask a simple question:

  • “Why did you have the surgery?”

Many times the patient will give an equally simple answer:

  • What other choice did I have?”

There are options to the ACL surgery and revision surgery as we will discuss below:

My ACL was fixed great, but now it is my meniscus

Here is a situation we often hear. It may be a problem affecting you. The ACL surgery went great but now the meniscus “is shot.”

I had ACL reconstruction surgery on my right knee more than 5 years ago. The surgeons congratulated me on having such a successful surgery. As I started rehab and soon afterward my knee really started to hurt. So I went for an x-ray to see if there was a problem with the tunnels or screws. When that showed everything was okay I went for an MRI. The MRI revealed that I developed a bucket handle meniscus tear. The tear was so bad there was nothing that could be repaired, my meniscus was in a state of disintegration.

My doctors still congratulate me on my ACL having healed so well. But now my knee is in a constant state of swelling and they are considering a meniscus transplant.

Now let’s talk about the meniscus – “Meniscus tears seen at the time of anterior cruciate ligament reconstruction are usually asymptomatic.”

Seen frequently in ACL rupture is the meniscus injury. There is a debate as to whether this meniscus injury should be treated or not depending on the extent of the damage to the meniscus. In December 2021 in the medical journal Arthroscopy (10), Orthopedic surgeon K. Donald Shelbourne wrote: “Meniscus tears seen at the time of anterior cruciate ligament reconstruction are usually asymptomatic, and treatment varies greatly between surgeons, with meniscus repair being used for tears that could be left in situ (or alone). Recent outcome studies of most types of lateral meniscus tears show that leaving the tears in situ can give equal or superior results. Meniscus repair being performed for degenerative medial meniscus tears does not give better results than removing the tears. As an alternative to repair, trephination (poking it with a needle) through the meniscus into the peripheral capsule can create many bloody channels to promote healing. Long-term follow-up of meniscus treatment with anterior cruciate ligament reconstruction can help us understand outcomes and prevent us from overtreating tears.”

Avoiding “Revision – Revision” – the Third ACL surgery – Back in the tunnels


Multiple studies have shown that the rate of return to the pre-injury level of sport is significantly lower following revision ACLR than following primary ACLR procedures.

In 2017, doctors writing in The Journal of Bone and Joint Surgery (11) suggest that it is important for orthopedic surgeons to attempt to restore proper anatomy and biomechanics during revision (the second ACL surgery) ACLR to minimize the rate of re-revision. (The third ACL surgery). Here is the surgeon’s checklist of guidelines.

  • They write that: Technical errors such as non-anatomic tunnel placement are some of the most common causes of graft failure after primary anterior cruciate ligament reconstruction.
  • When considering a revision ACLR in a patient with ACL graft failure, it is crucial to perform preoperative imaging, which should include an initial radiographic series, magnetic resonance imaging, and possibly computed tomography for further assessment of tunnel locations.
  • Revision ACLR may be performed in a 1 or 2-stage procedure depending on the size and location of the existing tunnels, bone stock, existing hardware, and infection status.
  • Use of autograft (patient) ligament tissue for revision ACLR has been shown to correlate with higher patient-reported outcomes and a significantly lower risk of subsequent graft rupture in comparison with allograft (donor) use.
  • Multiple studies have shown that the rate of return to the pre-injury level of sport is significantly lower following revision ACLR than following primary ACLR procedures.

It is important to consider that the findings above are considered excellent ACL reconstruction patient results. We ask, do these findings really merit an excellent? Here is more research to review:

  • ACL Reconstruction and the Meniscus: In the medical journal Arthroscopy, (12) doctors wrote: “Meniscectomy was performed in 65% of ACL tear procedures. This is concerning because studies have shown that, regardless of knee stability obtained after ACL reconstruction, meniscectomy accelerates degenerative joint changes.
  • ACL Reconstruction and Patellofemoral pain syndrome: Doctors writing in the journal Arthritis Care & Research, (13) note that Patellofemoral osteoarthritis is common following anterior cruciate ligament reconstruction and that post-surgical lack of knee rotation may be sufficient to initiate or accelerate patellofemoral cartilage degeneration.

The young athlete’s knee is not the same after ACL reconstruction

A January 2022 study in the Orthopaedic Journal of Sports Medicine (26) suggests that athletes display persistent muscle deficits (weakness) and altered limb-loading mechanics at the time of return to sport after anterior cruciate ligament reconstruction. How much deficit and altered mechanics? To find out the researchers compared adolescent athletes’ function and playing ability when they returned to sports following ACL reconstruction to adolescent athletes who never had ACL reconstruction.

  • There were 124 participants in this study; 62 patients who underwent ACL reconstruction (average age about 15.5 years old) and 62 healthy controls (average age about 15.3 years old).
  • Tests were done to capture joint motions during jump landing and single-limb squat tasks.
  • For jump landing, patients who underwent ACL reconstruction utilized significantly greater hip and significantly less knee power on the surgical limb compared with controls.
  • During single-limb squat, patients who underwent ACL reconstruction utilized significantly greater hip and significantly less knee power on the surgical limb compared with controls.
  • The ACL reconstruction group demonstrated lower pain and function scores and significantly lower quadriceps strength on the surgical limb than controls. There were no differences in surgical limb hamstring strength between the ACL reconstruction group and healthy controls.

Conclusion: “Compared with matched healthy controls, the participants who underwent ACL reconstruction in this study demonstrated an inferior objective profile (less strength and function) at a return to sport, consisting of deficits in surgical limb loading, self-reported outcomes, and strength.”

The younger hamstring graft is too stiff – Younger patients have worse surgical outcomes

A January 2022 study in the International Orthopaedics (31) by researchers at the University of Auckland. In this study, they examined if a younger patient’s hamstring tendon was “too stiff.” Here are the learning points of their study:

  •  “The hamstring tendon is the most commonly used autograft material in reconstructive surgeries of anterior cruciate ligament (ACL) tears. Younger patients have worse surgical outcomes, with a higher risk of re-rupture. (The researchers) hypothesized that age-related changes in hamstring tendon properties affect the tendon’s propensity to rupture when used as an autograft in ACL reconstructions.”

The researchers then compared hamstring tendon samples obtained from people aged 20 years or younger to samples obtained from older people.

  • The researchers found that tendon samples from the older group (stretched more easily) than the younger group, whereas the stress to failure was similar in the two groups.
  • The hamstring tendon from younger people has higher stiffness than tendon from older people, and the profile of gene expression (the ability to make proteins and signal or communicate with other cells in the knee)  in (the) tendon varies with age. These differences may negatively affect the performance of the hamstring tendon in ACL reconstructions in younger people.

Knee function deficits following ACL reconstruction measured by loss of vertical jump distance

An international team of researchers published their May 2022 study (32) in the British journal of sports medicine in which they suggested that male athletes perform a single leg vertical jump test to help identify performance and knee function deficits (weakness) at return to sport after ACL reconstruction. From the study: “Vertical jump performance (the power, acceleration and height the athlete can achieve in the jump) is a more representative metric (test) for knee function than horizontal hop performance (jump height and distance) in healthy individuals.”

The purpose of this study was more to determine if the vertical test accurately portrayed knee strength in the ACL reconstruction athlete, as the researchers noted: “It is not known what the biomechanical status of athletes after anterior cruciate ligament (ACL) reconstruction (ACLR) is at the time they are cleared to return to sport or whether vertical performance metrics better evaluate knee function.”

In determining the effectiveness of the vertical test to portray knee deficits in the ACL reconstruction patient, the researchers found: Jump performance, assessed by jump height and Reactive Strength Index (a test that may be best described as “explosiveness” with a main factor of this test vertical jumping height), was significantly lower in the ACL reconstructed knee than the non reconstructed knee and compared against controls (people who did not have surgery), with large effect sizes.

The conclusion of this study was: “During vertical jumps, male athletes after ACL reconstruction at return to sport still exhibit knee biomechanical deficits, despite symmetry in horizontal functional performance and strength tests. Vertical performance metrics like jump height and Reactive Strength Index can better identify interlimb asymmetries than the more commonly used hop distance and should be included in the testing battery for the return to sport.” In other words, jumping is a problem and it is better assessed with tests that can evaluate jumping height and explosiveness.

Ten years later, my knee is still not the same

In some patients, their knee is not the same. In some patients, ten years later their knee is not the same. Some people do very well with ACL reconstruction surgery, some do very well with second or revision ACL surgery. Some do well with the third ACL reconstruction/revision surgery. These are typically not the people we see in our office. We see the people who may have had a successful surgery, but their knee is not the same. They tell us stories like this one:

When I had the ACL reconstruction I had a difficult rehab. Maybe because I was pushing myself too hard. My knee just did not feel right. Almost a year after the surgery, the graft gave way and it pretty much wiped out my meniscus. In the revision surgery a tendon graft was used and most of my meniscus, which I was told was beyond repair, was removed. The surgery was a great success but my knee was never the same. I never really recovered. Here I am 10 years later now being managed along until I can get a knee replacement.


Does ACL reconstruction prevent posttraumatic osteoarthritis?

A September 2021 German study in the journal (translated into English) Sports Injury – Sports Damage (29) wrote: “The treatment of an anterior cruciate ligament rupture is still controversial. In particular, this applies to the question of conservative versus surgical treatment. The answer to this question is often based on consequential damage such as the development of posttraumatic osteoarthritis, secondary damage to the meniscus or cartilage, and participation in sports. ”

To answer this question, the researchers reviewed previously published studies and found: “Patients with an anterior cruciate ligament rupture are likely to be at a greater risk of developing progressive joint degeneration. A protective effect of cruciate ligament surgery has not been found in the evaluated studies. A general argument in favor of cruciate ligament surgery aiming to achieve a protective effect on hyaline articular cartilage seems obsolete based on the results and should therefore not be used in patient education in the future.”

Simply anterior cruciate ligament reconstruction does not appear to prevent posttraumatic osteoarthritis.

This was also suggested by a September 2021 paper in The Bone & Joint Journal (30) which also simply states: “Anterior cruciate ligament (ACL) rupture commonly leads to post-traumatic osteoarthritis, regardless of surgical reconstruction.”

ACL reconstruction and the development of posttraumatic osteoarthritis in more active people

A February 2021 study in The American journal of sports medicine (28) assessed the association between activity level after ACL reconstruction (ACLR) and the development of posttraumatic osteoarthritis. The focus of this study was to investigate the relationship between patient-reported outcomes and progressive cartilage degenerative changes at three years after ACL reconstruction.

  • Sixteen patients (45.7%) showed evidence of cartilage degeneration at 3 years, most frequently in the medial compartment (the inside knee 34%).
  • Increased activity at 3 years after ACL reconstruction was significantly associated with increased risk of medial compartment posttraumatic osteoarthritis.

In this study, the researchers used the MARX scale to determine a consistent level of activity. Patients who reported greater amounts of running, deceleration, cutting, and pivoting were more likely to develop posttraumatic osteoarthritis.

The fact that your knee is moving towards inevitable knee replacement should tell you that every day your knee is getting weaker.

By this time you can see that we are building an argument that instability in the ACL Reconstructed knee leads to a more accelerated breakdown of the knee. This does not have to be solely an osteoarthritis knee replacement someday in the future, it is a problem you have today. But knee replacement is the general direction you are moving in. The fact that your knee is moving towards inevitable knee replacement should tell you that every day your knee is getting weaker.

  • Researchers writing in the British Journal of Sports Medicine (14) found that if you had to have a revision or secondary ACL reconstruction surgery you were at advanced risk for osteoarthritis, ligament damage and weakness, and loss of knee function.
  • In fact, doctors writing in the Journal of Bone and Joint Surgery (15) wrote: “Despite the success of restoring joint stability and improving early functional outcomes after anterior cruciate ligament reconstruction, the long-term risk of developing symptomatic osteoarthritis requiring total knee replacement is higher than that in the uninjured population.”

Many people have issues with knee instability and function after anterior cruciate ligament reconstruction, it is not just you.

We have just presented a lot of research on the problems some patients have following ACL reconstruction surgery. But in reality, how often do ACL reconstruction complications and post-surgical concerns occur? If you are reading this article because you are considering ACL surgery, you may think to yourself, how many people does this really affect?

For you who had the surgery, it has happened one time too many because you have a lot of knee problems. While you may be led to believe that this is a problem you suffer from a small minority of patients, it is NOT just you, it is a lot of patients. How big a problem is this in the medical community? Consider this:

In 2015, a paper appeared in the journal Clinical Orthopedic Sports Medicine, (16) it came from researchers at Johns Hopkins University. The researchers looked at all the medical studies published in the field of clinical sports medicine with the goal of finding the top 100 most cited medical articles. This was not just a study in statistics, the subject matter of the top 100 articles would tell doctors and other health professionals what some of the biggest challenges in medicine were and how researchers were moving toward possible solutions.

  • 15 of the 100 ( a very heavy influence) dealt with an injury to the ACL. 

In 2017, European researchers looked solely at the top ACL 50 articles. They published their results in the journal International Orthopaedics. (17)

The top three articles cited were articles that were related to defining a scoring system to help clinicians understand the severity of symptoms related to knee ligament problems. The number 1 article was the 1985 “Rating systems in the evaluation of knee ligament injuries”(18)  that lead to the “Tegner Lysholm Knee Scoring Scale.” A questionnaire to grade and assess the patient’s knee problems.

Now if you had an ACL reconstruction and you are experiencing continued problems, you may have been given the questionnaire or were asked questions that pertain to these following problems broken up into these sections.

  • Section 1 – Do you Limp?
  • Section 2 – Do you need help with walking? Do you use a cane, a crutch, can you support your own weight without assistance?
  • Section 3 – How much pain do you have? How much pain do you have after certain levels of exertion?
  • Section 4 – Instability – when does your knee “give out”? Always? Never? At certain amounts of exertion?
  • Section 5 – To what extent does your knee lock up?
  • Section 6 – To what extent does your knee swell? Is swelling constant?
  • Section 7 – Can you climb stairs?
  • Section 8 – Can you squat?

Based on the amount of time clinicians spend researching and citing articles on “Knee scoring systems, one could suggest that the biggest problem facing the clinician is how do you determine how bad off a patient’s knee is? Second what is causing these problems?

What if I buy a really good brace? Study: Knee bracing does not appear to improve the clinical outcomes on the function and stability of ACL-reconstructed knees

An October 2019 study in the journal Orthopaedics and Traumatology, Surgery and Research (19) suggests that “knee braces could not provide superior clinical outcomes on knee functional scores and stability evaluations.”

Here is what they said:

  • “Knee brace has been commonly used as a device to protect the graft after reconstruction of anterior cruciate ligament (ACL). Studies have focused on the effects of braces after ACL reconstruction, and controversial results were reported.”

In this study, the researchers combined data from seven studies with 440 participants. After examining the patient outcomes following ACL reconstruction outcomes, the research team found:

  • “Knee bracing does not appear to improve the clinical outcomes on the function and stability for ACL-reconstructed knees. Thus, bracing for patients treated with ACL reconstruction should not be recommended routinely.

Does hyaluronic acid injections help with swelling and joint stiffness after ACL reconstruction?

A March 2022 paper in the Journal of clinical orthopaedics and trauma (33) sought to examine the effectiveness of hyaluronic acid injections in helping post ACL reconstruction patients with their problems of pain, swelling and joint stiffness. The study notes: “The patients often receive prolonged analgesic medications to control the inflammatory response and resume the pre-injury activities.”

This review study examined data from four previously published studies. In total 303 patients were assessed, 182 patients in the intraarticular hyaluronic acid injection group and 121 patients in the control group. The study analysis revealed: “Although the individual study demonstrated a short-term positive response regarding pain control and swelling reduction, the pooled analysis did not find any clinical benefit of intraarticular hyaluronic acid injection following ACLR surgery.”

It is time to talk about the other ligaments of the knee –
When the other knee ligaments are too weak to support the new ACL, this causes ACL surgery failure.

The ACL ligament does not sit in isolation. Your problem may be a knee ligament problem and it is not just the ACL, it is the other ligaments.

The ACL ligament does not sit in isolation. Your problem may be a knee ligament problem and it is not just the ACL, it is the other ligaments.
The ACL ligament does not sit in isolation. Your problem may be a knee ligament problem beyond the ACL. This illustration demonstrates the interaction of the knee ligaments.

The four major ligaments of the knee are:

Study: “Generalized Hypermobility, Knee Hyperextension, and Outcomes After Anterior Cruciate Ligament Reconstruction”


Let’s examine an October 2017 study in the medical journal Arthroscopy (20) led by the Minnesota Orthopedic Sports Medicine Institute and Department of Orthopedics, University of Michigan MedSport.

The title of the paper should say it all: Generalized Hypermobility, Knee Hyperextension, and Outcomes After Anterior Cruciate Ligament Reconstruction.

Here are the summary findings:

  • Doctors looked at 183  (knees) patients two years removed from ACL reconstruction
  • Patients underwent ACLR with either bone-patellar-tendon autograft, quadrupled hamstring autograft, or allograft tissue.

Knee Hypermobility – instability

  • Of the 183 patients:
    • Forty-one of 183 consecutive patients were categorized as hypermobile.
    • The remaining 142 were categorized as non-hypermobile.
  • ACL reconstruction failure was higher in the Hypermobile group (24.4% failure rate) compared with the Non-hypermobile group (7.7% failure rate)
  • The overall ACL injury rate (ACL graft injury, excessive graft laxity, plus contralateral (the other knee) ACL tear) was higher in the Hypermobile group (34.1%) compared with the Non-hypermobile group (12.0%)

In this above study, the focus is put on the ACL graft being too loose or lax. The new ACL is not holding the knee together as it should and this is causing whole knee instability.

  • BUT, what if the ACL graft was put into a knee that was already suffering from ligament laxity from the other ligaments?

“Preoperative laxity of the knee” and “Excessive graft laxity” as a cause of ACL surgery failure

Let’s go back to 2001 and a well-documented summary of ACL complications that can be found in the abstract of a classic lecture presentation from the Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh. This lecture was delivered in 2001. (21)

From 2001: “Many factors influence the overall success or failure of anterior cruciate ligament reconstruction, including the integrity of the secondary restraints (that is the supporting structures of the knee), the collateral ligaments, the mid-third capsular ligaments, the meniscus, and the iliotibial band), the preoperative laxity of the knee, the status of the articular and meniscal cartilage. . . “

As we noted in the research above untreated associated ligaments insufficiencies, in other words, the other knee ligaments were too weak to support the new ACL, which caused the failure.

The prevalence of knee hyperextension (knee instability) in ACL revision surgery patients
Research 2018-2021

We are now going to move forward to October 2018 in the American Journal of Sports Medicine. (22)

This is a huge study listing dozens of authors. The study’s abstract lists that the investigation was performed at The Carrell Clinic, Dallas, the Department of Orthopaedics, Washington University School of Medicine, St Louis, the Department of Orthopaedics and Rehabilitation, Vanderbilt University Medical Center, and Reedsburg Area Medical Center, Reedsburg, Wisconsin.

The researchers in this study presented a hypothesis about the impact of knee hyperextension in revision ACL reconstruction surgery. Knee hyperextension is defined as a 5-degree ability to bend the knee backward.

So the researchers went about examining ACL reconstruction patients for two years.

  • The average age of the patient was 26 years old
  • 42% of patients were female
  • There were 50% autografts, 48% allografts, and 2% that had a combination of autograft plus allografts.
  • Graft rupture was more prevalent in:
    • Younger patients
    • Those patients who used allograft
    • and patients who had hyperextension of greater than 5 degrees.

Conclusion of the study? 

  • This study revealed that preoperative physiologic passive knee hyperextension of greater than 5 degrees is present in one-third of patients who undergo revision ACLR.
  • Knee hyperextension of greater than 5 degrees is an independent significant predictor of graft failure after revision ACLR with a more than 2-fold risk of subsequent graft rupture in revision ACL surgery.

“Revision anterior cruciate ligament reconstruction restores knee laxity but shows inferior functional knee outcome”

Here is a 2019 study from the Stockholm Sports Trauma Research Center, Karolinska Institutet, Stockholm, Sweden published in the journal Knee surgery, sports traumatology, arthroscopy (23). What the researchers found was that a revision ACL reconstruction laxity problem can be surgically fixed, but it could not fix problems with knee function in many patients.

The researchers wrote “the final postoperative functional outcome is inferior”

“The findings of this study showed that anterior knee laxity is restored with revision bone-patellar tendon-bone autograft ACLR after failed primary hamstring tendons autograft ACLR, in the same cohort of patients. However, revision ACLR showed a significantly inferior functional knee outcome compared with primary ACLR. It is important for clinicians to inform and set realistic expectations for patients undergoing revision ACLR. Patients must be aware of the fact that having revision ACLR their knee function will not improve as much as with primary ACLR and the final postoperative functional outcome is inferior.”

 “Preoperative medial knee instability is an underestimated risk factor for revision ACLR failure”

University medical researchers in Germany published a July 2020 study in the journal Knee Surgery, Sports Traumatology, Arthroscopy (24) that warned their colleagues that a loose knee after ACL reconstruction is a leading cause for ACL reconstruction failure.

The researchers wrote: “The most important finding of this study was that preoperative medial knee instability is a risk factor for revision ACLR”

“The most important finding of this study was that preoperative medial knee instability is a risk factor for revision ACL reconstruction and should be adequately addressed at the time of revision ACL reconstruction. This study demonstrates the largest revision ACL reconstruction patient group with pre-and postoperative clinical examination data and a follow-up of 2 years published to date and it indicates that preoperative knee instability is an important factor for the treatment strategy of revision ACL reconstruction. Medial knee instability, high-grade anterior knee instability, and increased posterior tibial slope are risk factors for failure of revision ACL reconstruction and should be addressed at the time of revision surgery.”

“In spite of supposedly successful surgery, slight residual knee laxity may be found at follow-up evaluations after anterior cruciate ligament reconstruction (ACLR), and its clinical effect is undetermined”

Finally, a March 2021 study in The American Journal of Sports Medicine (25) wrote: “In spite of supposedly successful surgery, slight residual knee laxity may be found at follow-up evaluations after anterior cruciate ligament reconstruction, and its clinical effect is undetermined. . . In spite of supposedly successful surgery, slight residual knee laxity may be found at follow-up evaluations after anterior cruciate ligament reconstruction, and its clinical effect is undetermined

Conclusion: “A slightly loose graft at 6 months after anterior cruciate ligament reconstruction increased the risk of later ACL revision surgery and/or graft failure, reduced the length of the athlete’s sports career, caused permanent increased anterior laxity, and led to an inferior Lysholm (pain, disability, function) score.”

The road to preventing ACL revision surgery – ligament strengthening

In this video Ross Hauser, MD explains a simple injection technique – Prolotherapy for strengthening the ACL

Video transcript summary:

  • For Grade 1 and Grade 2 tear of ACL, Prolotherapy injections can be an effective non-surgical option
  • If somebody has a complete anterior cruciate ligament tear they should get surgery to repair it but then after surgery Prolotherapy should be considered because Prolotherapy will stimulate the healing and strengthening of the attachments of the transplanted ACL. There are two attachments of the anterior cruciate ligament – at the tibial tubercle and at the lateral femoral condyle. Prolotherapy strengthens these attachment points.
  • Prolotherapy is very effective at decreasing the pain, knee instability and the inability to exercise that occurs with ACL weakness or injury.
  • Athletes and non-athletes – people with physically demanding work can continue to train or work during treatment – there is typically no reason for immobilization.

The regenerative approach to Knee ligament weakness and degenerative injury

Throughout this article, we demonstrated research from the surgical community that discusses the problems of knee instability following an ACL reconstruction surgery. These problems can be severe enough that a second or even third surgery may be suggested. We have also demonstrated that these revision surgeries are, for the most part, less successful than the patient expects.

The problem of knee instability is a problem of damaged, untreated degenerative structures. This includes the three other main stabilizing ligaments in the knee the MCL, PLC, and LCL.

In the case of an overstretched or partially torn ligament, a treatment approach to strengthen and heal the injured ligament should be utilized. The treatment that stimulates ligament healing and regeneration is Prolotherapy.

In this video, Danielle R. Steilen-Matias, MMS, PA-C, of Caring Medical demonstrates how we treat a patient with a primary complaint of knee osteoarthritis.

  • The person in this video is being treated for knee osteoarthritis as the primary complaint. The treatment takes a few minutes. The person in this video is not sedated and tolerates the treatment very well. For some patients, we do provide IV or oral medications to lessen treatment anxiety and pain.
  • The first injection is given to the knee joint. The Prolotherapy solution is given here to stimulate repair of the knee cartilage, meniscal tissue, and the ACL as well.
  • The injections continue over the medial joint line making sure that all the tendons and ligaments such as the medial collateral ligament are treated.
  • This patient-reported the greatest amount of pain along the medial joint line. This is why a greater concentration of injections is given here.
  • The injections continue on the lateral side of the knee, treating the lateral joint line all the tendon and ligament attachments there such as the LCL or lateral collateral ligament.

Summary and Questions about our treatments?

Surgical outcomes for ACL tears have their own fair share of disappointing results, including as high failure rates as demonstrated in the research above. Second ACL tears or the need for later revision surgery will all but end a young athlete’s career. Using tissue from cadavers (allograft) or from a patient’s own tissue (autograft) is used for ACL reconstruction, as well as for many other areas of the body because it sounds promising to a patient in pain who is looking for repair, and is necessary in the instance of grade III (complete) tears. Despite the reconstructive surgery, the instability of the knee remains and that knee is in jeopardy for future injury.

ACL reconstruction can provide remarkable short-term pain relief. Temporarily they provide more stability to the joint. Unfortunately, the stability doesn’t last because the “new” ACL can not simulate exactly the same biology of the original ACL. If someone has a complete, grade 3 ligament tear, surgery is indicated. The cadaver or tendon graft that is replacing the torn ligament, however, will not function long-term like the original ACL. Once it starts becoming lax or weak, Knee instability occurs.

ACL grafts do not have the same pliability as nascent tissue. In other words, ligaments are pliable, they can stretch. Surgerized ACL no longer has the pliability and for the active person will cause long-term problems.

If you have questions about your knee pain and how we may be able to help you, please contact us and get help and information from our Caring Medical staff.

 

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References: 

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This article was updated April 14, 2022

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