KNEE

Overview:

The knee is a hinge joint. It is the femur’s meeting point (thigh bone) with the tibia (shin bone). With minimal bony approximation, the knee joint is heavily reliant on soft tissue structures for stability. These include ligaments, the meniscus, and tendons. Soft tissues include ligaments, meniscus, and tendons. An additional joint in the knee is the articulation of the patella (kneecap) with the femur. Numerous injuries can occur, some acute and some chronic, and many surgical procedures are used to address knee injuries and pain. A Foothills physical therapist will complete a comprehensive evaluation to determine the musculoskeletal causes of your knee or lower-body injury.

Common Knee Injuries

Ligament Tears:

There are four ligaments in the knee – two cruciate ligaments (ACL, PCL) and two collateral ligaments (MCL, LCL). Ligaments connect bone to bone, and these four ligaments serve to provide stability to the knee joint. The knee ligaments can be injured in a multitude of ways. Since they check the knee’s movement in specific directions, injury usually occurs when the knee is twisted or torqued abnormally.

Anterior Cruciate Ligament (ACL):

Probably the most ‘famous’ of the four knee ligaments, the ACL is most commonly injured by high torque within the knee causing a shift, tearing the ACL. Injury may be associated with an audible “pop” and immediate joint effusion (swelling within the joint). Injuries can be related to a direct blow to the knee. However, ACL injuries often occur with no contact at all. They can be isolated or associated with related injuries to other structures, including the meniscus, articular cartilage, or the other knee ligaments (MCL).

ACL reconstruction: An arthroscopic surgical procedure performed to restore the normal function of the ACL using a tissue graft. The surgeon will remove the original ACL tissue, drill new tunnels into the femur and tibia, and use a tissue graft to reconstruct the ACL. Surgeon preferences on graft type and surgical technique vary.

Post-op rehabilitation is essential in protecting the repair, restoring normal range of motion (ROM), reducing post-op swelling, and recovering normal muscle function. As restoration progresses, your physical therapist will begin to include additional exercises to maximize strength, endurance, power, and coordination to prepare for a return to normal activities.

Typically, rehabilitation following an ACL reconstruction can take up to and beyond 4-6 months, depending on associated injuries and goals following surgery. Your surgeon and therapist will work together to determine your readiness to return to sport.

Posterior Cruciate Ligament (PCL):

Less commonly injured than the ACL, the PCL also provides stability to the knee. The PCL checks the excessive motion of the tibia posterior on the femur and rotatory torque in the knee. Isolated PCL injuries aren’t common but do occur, often due to a direct blow to the tibia while the knee is bent (such as during a car accident or landing on the knee). The PCL is more commonly injured in combination with other ligaments and structures in the knee due to a high velocity, high torque injury. Suspected PCL injuries should also include evaluation of neurovascular structures.

PCL Reconstruction: Like an ACL reconstruction, the PCL is also repaired using a tissue graft to restore normal position and function. Repair is complicated due to the knee and vessels’ anatomy and nerves close to the PCL. Post-operative rehabilitation is similar to post-op ACL reconstruction with some differences. Most importantly, protecting the repair while restoring ROM, increasing strength, and reducing swelling are your physical therapist’s primary goals. As rehabilitation progresses, your therapist will work with you on restoring function and preparing you for a full return to activity.

Medial Collateral Ligament (MCL):

Another commonly injured ligament, complete tears of the MCL, are uncommon. Typically graded in degrees, an MCL sprain can be extremely painful (more so than ACL/PCL injuries). Often the MCL is injured because of a direct blow to the outside of the knee, causing excessive medial gapping. It can also be damaged due to high velocity, high torque activities such as pivoting or twisting.

MCL Reconstruction: Surgical reconstruction of the MCL is uncommon. Depending on other injured structures in the knee, an MCL sprain/tear will usually be treated conservatively with physical therapy. Because of the MCL’s anatomy and its proximity to the knee joint capsule, treatment is geared towards scarring down and allowing it to heal gradually. Your physical therapy will be focused on reducing pain, the gradual restoration of ROM, strengthening, and progressing to return to activity/sports.

Lateral Collateral Ligament (LCL):

The LCL is also not commonly injured. Its primary function is to prevent “gapping” of the knee joint’s lateral (outside) knee joint. Typically, the LCL is injured in combination with other knee structures (PCL, ACL, posterior joint capsule) due to high velocity, high torque injuries resulting in dislocation of the tibia on the femur.

LCL Reconstruction: Surgical repair involves using graft tissue to reconstruct the LCL. Other structures damaged will also be repaired depending on the injury and surgeon preference. Rehabilitation will focus on protecting the repair, restoration of ROM/Strength, and gradual return to normal activities. Other concomitant injuries to adjacent structures typically complicate physical therapy. Physical therapist/surgeon communication is essential.

Meniscal Tears:

The medial and lateral meniscus are circular, cartilaginous, wedged-shaped structures that sit on the tibia and serve to 1) provide shock absorption and 2) deepen the socket for the femoral condyles. The medial meniscus is more commonly torn than the lateral meniscus due to its relative immobility. Tears in the meniscus can occur in multiple areas (or zones) and can be of various shapes and sizes (radial, bucket-handle, etc.).

Meniscectomy: An arthroscopic surgical procedure where the damaged area of the meniscus is trimmed and removed. Advances in arthroscopic technology have made this procedure relatively simple as compared to the past. Physical therapy following a meniscectomy is focused on restoring ROM, strength, balance, and returning to normal activities. Typically, treatment can start immediately following surgery, and full recovery can be attained within 6-8 weeks, depending on the procedure’s scope.
Meniscus Repair: An arthroscopic surgical procedure in which the torn meniscus is repaired. Multiple factors determine whether or not the meniscus will be repaired, including age, type of tear, location of the tear, and tear size. The surgeon will use a suture to repair the torn meniscus, being careful to retain its original structure/shape. Physical therapy following a meniscal repair is more complicated than following a meniscectomy because of the healing time required for the repair. In rehab, your therapist will follow ROM and activity guidelines and work with your physician to ensure that the repair isn’t stressed. The meniscus will take up to 6-8 weeks to heal, at which point rehab can progress more quickly.
Meniscus Replacement: The least common procedure for meniscal injuries, a replacement is usually reserved for young, active patients with a severe meniscal injury. A meniscal graft will be surgically introduced into the joint and sutured into place. Post-operative rehabilitation will be slower and will follow specific pathways to allow for healing. Good surgeon/physical therapist communication and teamwork are critical.

Patellofemoral Pain/Dysfunction:

The patella (knee cap) is a sesamoid bone that articulates with the distal femur and serves to increase the quadriceps’ leverage during knee extension. It also helps to provide some protection to the anterior knee joint. Because of the patellofemoral joint’s dynamic nature, there are many causes of dysfunction resulting in anterior knee pain. While some causes are related to anatomical variances, many patellofemoral pain causes are dynamic and can be addressed through a comprehensive, individual physical therapy treatment plan. Your physical therapist should assess the entire kinetic chain (from foot to hip/core) when evaluating you. They should consider many factors, including walking/running biomechanics, standing posture, muscle length and strength throughout the lower extremity, and hip/core strength. Typically patellofemoral pain/dysfunction is treated non-operatively. However, in certain instances, surgery may occur. Procedures may include:

Arthroscopic Debridement – a debridement of the underside of the patella
MPFL Reconstruction – a reconstruction of the medial patellofemoral ligament (MPFL)
Lateral Release – the surgical release of the lateral retinaculum
Fulkerson Procedure – a surgical shift of the tibial tubercle
HTO (High Tibial Osteotomy) – a surgical realignment of the lower extremity

Patellar Tendonosis vs. Patellar Tendonitis:

Tendons connect muscle to bone. Therefore tendons serve to transfer energy from a contracting muscle to move the body part. The quadriceps (thigh) muscle is a large, powerful muscle on the front of the leg. When it contracts, energy is transferred through the quadriceps tendon, patella, and patellar tendon to extend the knee. If there is excessive force, overuse, and/or a muscle imbalance, micro-trauma in the tendon can occur. Tendonitis refers to active inflammation in the tendon tissue. Tendonosis refers to degenerative changes in the tendon. Both conditions are related, although tendinosis is more common due to ongoing micro-trauma, with or without inflammation. Over time, this condition results in pain and loss of function.

Physical therapy treatment will focus on unloading the affected tendon through activity modification, exercises focused on strengthening the entire kinetic chain, and improving technique and biomechanics during activity. Additionally, instrument-assisted soft tissue mobilization can be used to kick-start the healing process in the degenerative tissue. This technique can assist in tissue remodeling in combination with ongoing activity prescribed by your therapist.

Cartilage Defects:

At its articulation with the tibia, the femur’s distal end is covered by protective hyaline cartilage. Injuries and lesions to the hyaline cartilage are common in traumatic knee injuries. An osteochondral defect (OCD) can occur, leaving a “hole” or “crater” in the hyaline cartilage, which may or may not leave that section of bone exposed. There are several categorizations and grades of cartilage lesions within the knee, so the prognosis depends on multiple medical factors. Surgical treatment is usually the only option, although physical therapy can assist with activity modification, patient education, and strengthening.

Surgical Intervention: From arthroscopic fixation (“nailing”) of the lesion to more advanced techniques such as OATS, ACI, Carticel, or an osteochondral bone graft, there are multiple medical options to discuss with your surgeon. Physical therapy following any of these procedures is complicated by protecting the repair and healing time. Many patients will be restricted in weight-bearing and ROM for some time. Your physical therapist will work with your surgeon to develop the best pathway for your recovery.

Osteoarthritis:

Chronic trauma and breakdown of the hyaline cartilage in the knee is also referred to as Osteoarthritis (OA) or “wear and tear” arthritis. Osteoarthritis occurs when the cushioning and protective hyaline cartilage breaks down, resulting in decreased joint space and degenerative changes in the cartilage. This can become quite painful, especially during weight-bearing activities.

Conservative treatment for OA includes physical therapy. Your physical therapist will educate you on weight-management and activity modification, as well as prescribing exercises to strengthen and stretch the muscles surrounding the affected joint. Remaining active is an integral part of OA treatment, and your physical therapist can help you find activities that reduce the load on your joints.

Total Joint Replacement: Usually the last resort option for patients with severe OA and pain resulting in loss of function, a total knee arthroplasty (TKA) is a major surgical procedure that generally results in a brief hospital stay. The surgeon will remove the femur and tibia end, replacing them with prostheses that will serve as your new knee joint. Physical therapy following TKA is geared towards promoting safe mobility initially. As you gain confidence and the ability to bear weight, your physical therapist will work on regaining ROM, strength, and, most importantly, function.

Common Lower Body Injuries:

Several injuries can occur in the lower extremity that may or may not be associated with a particular joint. These typically present as muscle strains (or pulls) that can limit one’s abilities and become nagging and chronic.