Medial patellofemoral ligament

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Medial patellofemoral ligament
Medial view of a flexed knee is shown. Medial-view-of-a-flexed-knee-is-shown-Anatomy-of-the-MPFL-AMT-adductor-magnus-tendon.png
Medial view of a flexed knee is shown.
Fig 1. Medial view of a flexed knee is shown. Anatomy of the MPFL. (AMT, adductor magnus tendon; ATT, adductor tendon tubercle; GTT, gastrocnemius tendon tubercle; MPFL, medial patellofemoral ligament; MQTFL, medial quadriceps tendonefemoral ligament.)

The medial patellofemoral ligament (MPFL) is one of several ligaments on the medial aspect of the knee. It originates in the superomedial aspect of the patella and inserts in the space between the adductor tubercle and the medial femoral epicondyle. The ligament itself extends from the femur to the superomedial patella, and its shape is similar to a trapezoid. It keeps the patella in place, but its main function is to prevent lateral displacement of the patella. [1]

Contents

Structure

The MPFL is located in the second soft tissue layer in the knee; this layer also includes the medial collateral ligament. The middle layer has the most consequential role in the patella's stabilization. The MPFL's origin is on the femur between the medial femoral epicondyle and the adductor tubercle, while being superior to the superficial medial collateral ligament. From the origin, it moves anteriorly, and combines with the deep portion of the vastus medialus oblique, inserting to the superomedial side of the patella, creating greater stability in the joint. [1]

Function

The purpose of the MPFL is to keep the patella stabilized; the ligament itself is responsible for 50–80% of the stability that is needed to prevent lateral patellar dislocation. [2] The ligament is able to gain this stability by keeping the patella stable in the trochlear groove. The addition of two other ligaments: the medial patellotibial ligament (MPTL) and the medial patellomeniscal ligament (MPML) aide the MPFL to maintain stabilization [1]

Clinical significance

The MPFL is the primary stabilizer to lateral displacement of the patella providing approximately 50–60% of restraining force. [3] Injury to the MPFL is most common during a non-contact twisting action. The most likely time for the patella to shift laterally is during the first 20–30 degrees of flexion as the quadriceps tighten simultaneously and pull the patella laterally. Beyond 30 degrees, the quadriceps tendon and patellar ligament pull the patella posterior into the groove of the knee joint making lateral dislocation of the patella unlikely.

Dislocation recurs in about 15–44% of cases, [4] and symptoms continue in about half. Recurrence of a laterally displaced patella is more common as the incidence of dislocation continues in the affected individual. Repairing the MPFL can be done surgically through an MPFL reconstruction. Indications for surgical incisions are two documented patellar dislocations and exam findings of excessive lateral patellar mobility.

MPFL reconstruction involves attaching two connections to the patella and one to the femur. This reconstruction holds the femur and patella in place.

Injury

Injuries to the MPFL are rare, and mostly occur in athletes. With lateral patellar dislocation, the MPFL is ruptured 90% of the time. [1] The patella rests in the trochlear, which is found in the distal part of the femur. The patella can dislocate from the groove because of trauma or an unnatural twisting of the knee. [5] When dislocated, the soft tissue layer that the patella rests in is damaged; the patella is forced out of its groove and back into place. The knee dislocates towards the outside of the leg, leaving the MPFL torn. If the injury to the ligament is left untreated, it may be able to heal on its own, but likely in a loosened or lengthened position. This leaves the patella vulnerable to repeated dislocation in the future. In turn, repeated dislocations can lead to tearing cartilage in the knee. Once damaged, there is increased risk of patellofemoral arthritis, which is significantly more difficult to treat than the initial tear. [6]

Nonsurgical treatment

For nonsurgical treatment of the MPFL, the knee must not have any loose pieces of soft tissue, cartilage, or bone within it. Initially, patients have their knees immobilized for the ligament to heal. Physical therapy is often prescribed as a nonsurgical treatment of a tear, in which functional rehabilitation and range of motion exercises that focus primarily on the hips, gluteal muscles, and quadriceps are used to strengthen the muscles surrounding the knee. During the recovery phase, heat and ice are often applied as pain managers before and after treatment. [7]

Surgical treatment

Patients may be restricted from eating and drinking on the day of the surgery. [7] During surgery, patients are given regional anesthesia and a nerve block in the spinal cord that numbs the lower half of the body, and an IV for sedation. An orthopedic surgeon replaces the injured ligament with either a hamstring tendon from the patient [6] or from a allograft tendon from a cadaver [8] The surgeon uses an arthroscope to view the interior of the knee, and the reconstruction itself is performed with two small incisions. Initial surgery takes approximately one hour, and the patient is usually released on the day of the surgery. [6]

Most MPFL surgeries are successful without any complications. MPFL surgeries have a 95% success rate. [9] Complications may include fractures, infections, or blood clots. In children, this surgery can be safely performed in open growth plates. Formerly, children were placed in a brace after the procedure, but this practice increased the risk of more dislocations before skeletal maturity and is no longer used. [6]

Rehabilitation for an MPFL repair usually involves physical therapy, with the initial recovery time being 4–7 months. [6] During the immediate post-operation phase, the knee is protected at all times. Patients do not bear weight on the knee for the first two weeks after surgery, with no range of motion. Typically, after six weeks, the patient starts physical therapy. If the patient is an athlete, their doctor and physical therapist must approve their return to sports. [10]

Related Research Articles

<span class="mw-page-title-main">Knee</span> Leg joint in primates

In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia, and one between the femur and patella. It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis.

<span class="mw-page-title-main">Patella</span> Kneecap, bone covering knee joint

The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as mice, cats, birds and dogs, but not in whales, or most reptiles.

<span class="mw-page-title-main">Anterior cruciate ligament</span> Type of cruciate ligament in the human knee

The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments in the human knee. The two ligaments are also called "cruciform" ligaments, as they are arranged in a crossed formation. In the quadruped stifle joint, based on its anatomical position, it is also referred to as the cranial cruciate ligament. The term cruciate translates to cross. This name is fitting because the ACL crosses the posterior cruciate ligament to form an "X". It is composed of strong, fibrous material and assists in controlling excessive motion. This is done by limiting mobility of the joint. The anterior cruciate ligament is one of the four main ligaments of the knee, providing 85% of the restraining force to anterior tibial displacement at 30 and 90° of knee flexion. The ACL is the most injured ligament of the four located in the knee.

<span class="mw-page-title-main">Luxating patella</span> Medical condition

A luxating patella, sometimes called a trick knee, is a condition in which the patella, or kneecap, dislocates or moves out of its normal location. It can be associated with damage to the anterior cruciate ligament.

<span class="mw-page-title-main">Anterior cruciate ligament reconstruction</span> Surgical process

Anterior cruciate ligament reconstruction is a surgical tissue graft replacement of the anterior cruciate ligament, located in the knee, to restore its function after an injury. The torn ligament can either be removed from the knee, or preserved before reconstruction through an arthroscopic procedure. ACL repair is also a surgical option. This involves repairing the ACL by re-attaching it, instead of performing a reconstruction. Theoretical advantages of repair include faster recovery and a lack of donor site morbidity, but randomised controlled trials and long-term data regarding re-rupture rates using contemporary surgical techniques are lacking.

<span class="mw-page-title-main">Vastus medialis</span> Extensor muscle located medially in the thigh that extends the knee

The vastus medialis is an extensor muscle located medially in the thigh that extends the knee. The vastus medialis is part of the quadriceps muscle group.

The knee examination, in medicine and physiotherapy, is performed as part of a physical examination, or when a patient presents with knee pain or a history that suggests a pathology of the knee joint.

<span class="mw-page-title-main">Lower extremity of femur</span>

The lower extremity of femur is the lower end of the femur in human and other animals, closer to the knee. It is larger than the upper extremity of femur, is somewhat cuboid in form, but its transverse diameter is greater than its antero-posterior; it consists of two oblong eminences known as the lateral condyle and medial condyle.

<span class="mw-page-title-main">Fibular collateral ligament</span> Collateral fibular ligament

The lateral collateral ligament is an extrinsic ligament of the knee located on the lateral side of the knee. Its superior attachment is at the lateral epicondyle of the femur ; its inferior attachment is at the lateral aspect of the head of fibula. The LCL is not fused with the joint capsule. Inferiorly, the LCL splits the tendon of insertion of the biceps femoris muscle.

<span class="mw-page-title-main">Anterior cruciate ligament injury</span> Ligament injury near the knee

An anterior cruciate ligament injury occurs when the anterior cruciate ligament (ACL) is either stretched, partially torn, or completely torn. The most common injury is a complete tear. Symptoms include pain, an audible cracking sound during injury, instability of the knee, and joint swelling. Swelling generally appears within a couple of hours. In approximately 50% of cases, other structures of the knee such as surrounding ligaments, cartilage, or meniscus are damaged.

<span class="mw-page-title-main">Patellar tendon</span> Tendon in the human knee

The patellar tendon is the distal portion of the common tendon of the quadriceps femoris, which is continued from the patella to the tibial tuberosity. It is also sometimes called the patellar ligament as it forms a bone to bone connection when the patella is fully ossified.

<span class="mw-page-title-main">Unhappy triad</span> Medical condition of the knee

The unhappy triad, also known as a blown knee among other names, is an injury to the anterior cruciate ligament, medial collateral ligament, and meniscus. Analysis during the 1990s indicated that this 'classic' O'Donoghue triad is actually an unusual clinical entity among athletes with knee injuries. Some authors mistakenly believe that in this type of injury, "combined anterior cruciate and medial collateral ligament disruptions that were incurred during athletic endeavors" always present with concomitant medial meniscus injury. However, the 1990 analysis showed that lateral meniscus tears are more common than medial meniscus tears in conjunction with sprains of the ACL.

<span class="mw-page-title-main">Quadriceps tendon</span>

In human anatomy, the quadriceps tendon works with the quadriceps muscle to extend the leg. All four parts of the quadriceps muscle attach to the shin via the patella, where the quadriceps tendon becomes the patellar ligament. It attaches the quadriceps to the top of the patella, which in turn is connected to the shin from its bottom by the patellar ligament. A tendon connects muscle to bone, while a ligament connects bone to bone.

<span class="mw-page-title-main">Patellofemoral pain syndrome</span> Medical condition

Patellofemoral pain syndrome is knee pain as a result of problems between the kneecap and the femur. The pain is generally in the front of the knee and comes on gradually. Pain may worsen with sitting down with a bent knee for long periods of time, excessive use, or climbing and descending stairs.

<span class="mw-page-title-main">Intercondylar fossa of femur</span> Extension of the thigh bone that secures the knee

The intercondylar fossa of femur is a deep notch between the rear surfaces of the medial and lateral epicondyle of the femur, two protrusions on the distal end of the femur that joins the knee. On the front of the femur, the condyles are but much less prominent and are separated from one another by a smooth shallow articular depression called the patellar surface because it articulates with the posterior surface of the patella (kneecap).

Patellar subluxation syndrome, is an injury that is concerned with the kneecap. Patellar subluxation is more common than patellar dislocation and is just as disabling.

<span class="mw-page-title-main">Patellar dislocation</span> Medical condition

A patellar dislocation is a knee injury in which the patella (kneecap) slips out of its normal position. Often the knee is partly bent, painful and swollen. The patella is also often felt and seen out of place. Complications may include a patella fracture or arthritis.

<span class="mw-page-title-main">Knee pain</span> Medical condition

Knee pain is pain in or around the knee.

<span class="mw-page-title-main">Medial knee injuries</span> Medical condition

Medial knee injuries are the most common type of knee injury. The medial ligament complex of the knee consists of:

Blumensaat's line is a line which corresponds to the roof of the intercondylar fossa of femur as seen on a lateral radiograph of the knee joint. The angle at which this line appears on the radiograph can be used to determine the position of the patella or diagnose an ACL injury.

References

  1. 1 2 3 4 Luxenburg, Dylan; Rizzo, Michael G. (2024), "Anatomy, Bony Pelvis and Lower Limb: Medial Patellofemoral Ligament", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   35593802 , retrieved 2024-03-12
  2. ↑ Guerrero, Patrick; Li, Xinning; Patel, Ketan; Brown, Michael; Busconi, Brian (2009-07-30). "Medial patellofemoral ligament injury patterns and associated pathology in lateral patella dislocation: an MRI study". Sports Medicine, Arthroscopy, Rehabilitation, Therapy, and Technology. 1 (1): 17. doi: 10.1186/1758-2555-1-17 . ISSN   1758-2555. PMC   2732599 . PMID   19643022.
  3. ↑ Krebs, Collin; Tranovich, Meaghan; Andrews, Kyle; Ebraheim, Nabil (June 2018). "The medial patellofemoral ligament: Review of the literature". Journal of Orthopaedics. 15 (2): 596–599. doi:10.1016/j.jor.2018.05.004. PMC   5990246 . PMID   29881201.
  4. ↑ Ercan, Niyazi (2024-01-12). Management of the First Patellar Dislocation. IntechOpen. ISBN   978-0-85466-229-6.
  5. ↑ MD, Riley Williams (2020-12-01). "Medial Patellofemoral Ligament Injury | MPFL Tear | MPFL Insufficiency | Orthopedic Knee Specialist | Manhattan, Brooklyn, New York City NY". Riley J. Williams III, MD - Orthopedic Surgeon. Retrieved 2024-03-18.
  6. 1 2 3 4 5 "Medial Patellofemoral Ligament (MPFL) Reconstruction | HSS". Hospital for Special Surgery. Retrieved 2024-03-18.
  7. 1 2 "MPFL Injury & Reconstruction". Alexander Orthopaedics. Retrieved 2024-03-18.
  8. ↑ McNeilan, Ryan; Everhart, Joshua; Mescher, Patrick; Abouljoud, Moneer; Magnussen, Robert; Flanigan, David (April 26, 2024). "Graft Choice in Isolated Medial Patellofemoral Ligament Reconstruction: A Systematic Review With Meta-analysis of Rates of Recurrent Instability and Patient-Reported Outcomes for Autograft, Allograft, and Synthetic Options". Arthroscopy: The Journal of Arthroscopic and Related Surgery. 34 (4): 1340–1354. doi:10.1016/j.arthro.2017.11.027. PMID   29366741 – via PubMed.
  9. ↑ Smith, Marvin K.; Werner, Brian C.; Diduch, David R. (June 2018). "Avoiding Complications with MPFL Reconstruction". Current Reviews in Musculoskelet Medicine. 11 (2). National Library of Medicine: 241–252. doi:10.1007/s12178-018-9479-y. PMC   5970114 . PMID   29752638.
  10. ↑ "Medial Patellofemoral Ligament (MPFL) Reconstruction Rehabilitation Protocol | Stony Brook Medicine". www.stonybrookmedicine.edu. Retrieved 2024-03-19.
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