WHAT IS A LIGAMENT INJURY/CHRONIC SPRAIN?
- Joints are surrounded by fibrous connective tissue (called ligaments) that attach bones to bones and help to stabilize the joint.
- A ligament sprain in the knee occurs when these ligaments are stretched beyond the normal range of motion. Ligament sprains can be minor, but in more severe cases the ligaments can be torn, leading to joint instability.
- Ligament sprains are classified into three grades based on severity: Grade 1 (mild stretching with microscopic tears), Grade 2 (partial tear), and Grade 3 (complete tear) [Logerstedt et al, 2017].
- Chronic sprains occur when the ligament is repeatedly overstretched, creating increased laxity.
WHAT IS A MEDIAL COLLATERAL LIGAMENT (MCL) SPRAIN OR TEAR?
- Medial Collateral Ligament (MCL) injuries typically result from a valgus force applied to the knee, such as a
direct blow to the outside (lateral aspect) of the knee. MCL injuries are common
in contact sports and often heal with conservative management, although
severe or combined injuries may require further intervention [Laprade et al, 2012; Reider, 1996].
WHAT IS A LATERAL COLLATERAL LIGAMENT (LCL) SPRAIN OR TEAR?
- Lateral Collateral Ligament (LCL) injuries typically result from a varus force, such as a blow to the inside (medial aspect) of the
knee. LCL injuries are less common and often occur with other ligament
injuries. LCL injuries may have a poorer healing response and they may require surgical repair, especially in cases of
multiligamentous injury [Grawe et al, 2018].
WHY DO LIGAMENT SPRAINS NOT HEAL?
- In some cases a ligament sprain may not heal. Following an injury, with the mix of collagen fibers the exra-cellular matrix changes. The new collagen fibers are smaller in diameter and less densely packed compromising the strength of the ligament and leading to weaker scar tissue [Achari et al, 2011].
- The collagen fibers also exhibit an abnormal cross-linked pattern and can exhibit “greater stress relaxation” making the ligament elongate more when stressed [Frank et al 1999; Thornton et al 2000]. This laxity can lead to extra stress on the joint and possibly early onset post-traumatic osteoarthritis [Øiestad et al 2009].
HOW DO YOU KNOW IF YOU HAVE A LIGAMENT SPRAIN?
- Symptoms can vary in intensity depending on the severity of the medial collateral ligament (MCL) or lateral collateral ligament (LCL) sprain, and can include:
- Pain: Knee pain typically localizes to the inner side of the knee for MCL sprains and on the outer side for LCL sprains. The pain is typically exacerbated by stress on the outside of the knee for MCL injuries and inside of the knee for LCL injuries [Laprade et al, 2012; Logerstedt et al, 2017].
- Swelling: Swelling around the knee joint can develop immediately or within a few hours after the injury [Laprade et al, 2012; Logerstedt et al, 2017].
- Tenderness: Tenderness typically occurs along the course of the ligament [Laprade et al, 2012; Logerstedt et al, 2017].
- Instability: A feeling of instability or the knee "giving way" can occur, particularly in more severe injuries such as Grade 2 or 3 sprains [Laprade et al, 2012; Logerstedt et al, 2017].
- Limited Range of Motion: Reduced range of motion can occur due to pain and swelling, making it difficult to fully extend or flex the knee [Laprade et al, 2012; Logerstedt et al, 2017].
- Bruising: Bruising around the knee may appear within a few days after the injury [Laprade et al, 2012; Logerstedt et al, 2017].
- In chronic ligament sprains or complete ligament injury the symptoms can vary, and patients can experience continued pain, increased laxity, joint instability and increased risk of further injury.
HOW ARE THESE INJURIES DIAGNOSED?
- Diagnosis of a ligament injury is based on detailed history, physical examination, and imaging. Certain physical tests may be utilized to reproduce symptoms and assess for joint laxity.
- The majority of ligaments are superficial and can be assessed with musculoskeletal ultrasound.
- X-ray imaging may also be utilized to determine presence of a bone injury in addition to ligament injury, but can not directly image soft tissue injuries.
- Diagnostic ultrasound
has been shown to be an effective imaging modality for diagnosing
lateral collateral ligament (LCL) and medial collateral ligament (MCL)
sprains.
- In one study, by Elshimy et al. ultrasound had a higher diagnostic accuracy for collateral ligament injuries when compared to MRI. For diagnosing collateral ligament injuries, ultrasound showed a sensitivity of 92.3%, specificity of 100%, positive predictive value (PPV) of 100%, negative predictive value (NPV) of 94.4%, and overall accuracy of 96.7% [Elshimy et al, 2023].
- In another study, ultrasound correctly diagnosed MCL injuries in 94% of cases [Lee et al, 1996].
- Sekiya et al. also highlighted the utility of dynamic ultrasound in evaluating posterolateral corner knee injuries, including the LCL. In this study, they reported that a dynamic ultrasound stress test with varus stress showed a sensitivity of 83% and specificity of 100% for LCL injuries, with a positive predictive value of 100% [Sekiya et al, 2010].
- Diagnostic ultrasound can be a cost-effective alternative compared to a MRI, and a rapid and dynamic imaging modality that can be used during your visit. Ultrasound's effectiveness can be operator-dependent and at Boston Sports & Biologics our clinic is AIUM accredited for musculoskeletal ultrasound and all of our providers are RMSK board certified in diagnostic ultrasound.
- Magnetic resonance imaging (MRI) is effective for diagnosing medial collateral ligament (MCL) and lateral collateral ligament (LCL) sprains and the presence of injury to the ligament.
- MRI has demonstrated high sensitivity and specificity for detecting MCL and LCL injuries.
For instance, MRI has shown a sensitivity of 79.1% for MCL and 55.6%
for LCL injuries, with moderate specificity (46.7% for MCL and 68.4% for
LCL) [Li et al, 2022].
- MRI is more sensitive in detecting MCL lesions compared
to clinical examination and can reliably diagnose MCL injuries, although
it may underestimate the grade of instability in some cases [Meyer et al, 2022].
HOW ARE CHRONIC LIGAMENT SPRAINS TREATED?
Nonoperative Treatment:
- For
chronic MCL and LCL sprains, nonoperative management is often the first
line of treatment, especially for lower-grade injuries. This approach includes:
- Physical Therapy: Focused on strengthening the surrounding musculature, improving range of motion, and proprioceptive training [Marchant et al, 2011; Reider, 1996; Laprade et al, 2012].
- Bracing: Functional bracing can provide stability and support during rehabilitation and daily activities [Reider, 1996; Laprade et al, 2012].
- Activity Modification: Avoiding activities that exacerbate symptoms and gradually returning to sports or high-demand activities as tolerated [Kim et al, 2016].
Orthobiologics Treatments:
- Platelet-Rich Plasma (PRP): PRP is a form of regenerative medicine that uses the patient’s own platelets to promote the healing of the injured ligament. PRP injections are prepared in the office by drawing a patient’s blood and concentrating the platelets before injecting them into the injured or diseased tissue.
- Clinical Case Reports:
Yoshida and Marumo reported successful treatment of chronic MCL
injuries in three patients using autologous leukocyte-reduced PRP
injections, with all patients returning to sport activities and showing
complete healing on MRI [Yoshida & Marumo, 2019].
- Animal Studies:
LaPrade et al. found that PRP did not improve ligament healing in an
acute MCL injury model in rabbits, and higher concentrations of PRP were
detrimental to ligament strength and histological characteristics.
Similarly, Amar et al. reported no significant improvement in MCL
healing with PRP in a rat model [LaPrade et al, 2018; Amar et al, 2015].
- Mesenchymal Stem Cells (MSCs):
- Animal Studies:
Saether et al. demonstrated that primed MSCs improved healing metrics
in a rat MCL injury model, suggesting enhanced anti-inflammatory effects
and better structural repair [Saether et al, 2016].
Prolotherapy Injections:
- Prolotherapy injections
have been explored as a treatment option for chronic medial collateral
ligament (MCL) and lateral collateral ligament (LCL) injuries in the
knee, but the evidence is limited and mixed. The mechanism of action behind prolotherapy is not completely understood, however, current theory holds that the injected irritating solution stimulates the natural healing process of the body by initiating a local inflammatory and then healing cascade.
- A case report by Ada and Yavuz documented the use of prolotherapy in a rugby player with a grade 2 MCL sprain, showing positive clinical and
radiological outcomes after a 3-week course of 15% dextrose combined with 0.2% lidocaine injections. The patient was pain-free with a full range of motion and able to perform rugby-specific movements at the end of the treatment period [Ada and Yavuz, 2015].
- In a controlled laboratory study by Jensen et al., prolotherapy with
dextrose injections in a rat model of MCL injury increased the cross-sectional area of the ligaments but did not significantly alter other mechanical properties or collagen fibril characteristics compared to controls. This suggests that while prolotherapy may induce some structural changes, its clinical benefits may not be directly related to improvements in ligament biomechanics [Jensen et al, 2008].
- A systematic review and network meta-analysis by Goh et al. compared
prolotherapy with other injection therapies for chronic soft tissue injuries. The review found that prolotherapy did not offer statistically significant pain benefits over other injection therapies for chronic soft tissue injuries, including corticosteroids, hyaluronic acid, and platelet-rich plasma (PRP), but showed some potential for functional improvement compared to non-injection therapies and corticosteroid injections at specific time points [Goh et al, 2021].
Operative Treatments:
- Minimally Invasive Percutaneous MCL surgery has been described with good results, including novel techniques described by Dr. Sussman with the Tenex device.
- Ultrasound Guided Debridement with Tenex: This technique involves using ultrasonic energy to debride the chronic degenerative MCL tissue. It has been described in a case report for the management of a chronic grade II MCL sprain, resulting in significant symptom relief and functional improvement [Park et al, 2022].
- Multiple Needle Puncturing/Percutaneous Release: Bellemans et al. described a technique where multiple punctures are made in the MCL using a 19-gauge needle to progressively stretch the ligament [Bellemans et al, 2010]. Fakioglu et al. reported on the percutaneous release of the MCL during arthroscopic medial meniscectomy in tight knees. This technique involves controlled release of the posterior portion of the MCL using a needle [Fakioglu et al, 2013].
- Open surgical
intervention is considered for patients with chronic instability,
high-grade injuries, or when nonoperative management fails:
- MCL Reconstruction:
Is typically indicated for high grade chronic LCL injuries (grade III) or when there is associated
multiligamentous injury. Surgical techniques involve anatomical reconstruction
using autografts or allografts to restore stability to the knee [Laprade et al, 2012[5-6]; Wijdicks et al, 2010; Miyamoto et al, 2009].
- LCL Reconstruction:
Similar to MCL sprains, chronic high-grade LCL injuries (grade III) or those with associated
posterolateral corner injuries may require surgical reconstruction.
This involves reattaching or reconstructing the ligament to restore stability [Krukhaug et al, 1998; Bushnell et al, 2010; Grawe et al, 2018].
