Patella fracture

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Patella fracture
Other namesBroken kneecap
Fracpetella.PNG
A fracture of the patella seen on a lateral view
Specialty Orthopedics
Symptoms Pain, swelling, bruising to front of the knee [1]
Complications Injury to the tibia, femur, or knee ligaments [2]
TypesStable, displaced, comminuted, open [1]
CausesTrauma to the front of the knee [1]
Diagnostic method Based on symptom, confirmed with X-rays. [3]
Differential diagnosis Bipartite patella [3]
Treatment Casting, splinting, surgery [2]
Prognosis Generally good with treatment [2]
Frequency~ 1% of fractures [3]

A patella fracture is a break of the kneecap. [1] Symptoms include pain, swelling, and bruising to the front of the knee. [1] A person may also be unable to walk. [1] Complications may include injury to the tibia, femur, or knee ligaments. [2]

Contents

It typically results from a hard blow to the front of the knee or falling on the knee. [1] Occasionally it may occur from a strong contraction of the thigh muscles. [1] Diagnosis is based on symptoms and confirmed with X-rays. [3] In children an MRI may be required. [3]

Treatment may be with or without surgery, depending on the type of fracture. [2] Undisplaced fracture can usually be treated by casting. [2] Even some displaced fractures can be treated with casting as long as a person can straighten their leg without help. [2] Typically the leg is immobilized in a straight position for the first three weeks and then increasing degrees of bending are allowed. [2] Other types of fractures generally require surgery. [2] [4]

Patella fractures make up about 1% of all broken bones. [3] Males are affected more often than females. [3] Those of middle age are most often affected. [3] Outcomes with treatment are generally good. [2]

Signs and symptoms

Also known as a broken kneecap, a patella fracture usually follows a history of trauma and commonly presents with swelling, pain, bruising and inability to both bend and straighten the knee. [5] The pain is worse when trying to stand and the person may be unable to walk. The pain can also be aggravated by prolonged periods of sitting. [1] [5] A painful defect may be felt in the knee and there may be blood in the joint. [6]

Complications

Complications may include injury to the tibia, femur, or knee ligaments. [2] In the longer term, the knee may not regain full movement, pain may persist and there is an increased likelihood of osteoarthritis of the knee. [7] If there is an associated open wound as in an open fracture, complications also include risk of infection, inability of the broken bones to reunite and osteonecrosis. [7]

Diagnosis

A vertical patella fracture with the fracture line marked by a black arrow Patella fracture.JPG
A vertical patella fracture with the fracture line marked by a black arrow

Diagnosis is based on symptoms and confirmed with X-rays. [3] In children an MRI may be required. [3]

Differential diagnosis

Bipartite patella Patella bipartita.jpg
Bipartite patella

Some people have a normal bipartite patella or two-part patella which can appear as a fracture. The fragment is usually seen in the top outer corner of the patella and can be distinguished from a fracture by being present in both knees. [6]

Types

The patella can break in various ways depending on the way it is injured, and into two or more pieces. [1] Types include transverse, with one fracture line and is the most common type, [5] marginal, osteochondral and the rare vertical type, or stellate, where a direct compression force gives rise to a comminuted pattern. [5] [7] Patella fractures can be further classified as displaced, where the broken ends of bone do not line up correctly and separate by more than 2mm, or undisplaced and stable where pieces of bone remain in contact with each other. [1] [7] If fragments of patella bone stick out from the skin it is known as an open patella fracture, and closed if the overlying skin is intact. [1]

Treatment

Treatment may be with or without surgery, depending on the type of fracture and whether the overlying skin is intact or broken. [2]

Conservative

Undisplaced fractures can usually be treated by casting. [2] Even some displaced fractures can be treated with casting as long as the person can straighten their leg without help, thus confirming that the quadriceps mechanism of the leg is intact. [2] [8] In this case the leg is immobilized in a straight position for the first three weeks and then increasing degrees of bending are allowed as healing occurs. [2]

Surgery

Tension band wiring: front and side view Zuggurtungs-Osteosynthese bei Patella-Querfraktur.png
Tension band wiring: front and side view

Most patella fractures are transverse or comminuted, hence the quadriceps mechanism is disrupted and they are treated by a combination of wires in a tension band construct. This unites the fractured bones, reconstructing the straightening mechanism of the leg. [5] [6]

If the patella is broken in several places, that is comminuted, then traditionally a patellectomy (removal of the whole patella) is performed in order to reconstruct the extensor mechanism and prevent the onset of an extension lag at the knee joint, resulting in instability. [5] [8] [9] Some surgeons however would rather opt for internal fixation. [8] A partial patellectomy is removal of only a portion of the patella, and may be carried out if at least 60% of the patella can be maintained. [6] [8]

Open fractures of the patella require emergency treatment with irrigation, debridement and fixation. [6]

Rehabilitation

Irrespective of surgical or non-surgical resolution to the fracture, a physical therapist can advise on progressive weight-bearing exercises and help with strengthening muscles of the leg, improving range of motion of the knee and in reducing stiffness. [1] [5]

Prognosis

Outcomes with treatment are generally good, [2] unless there is involvement of the articular surface or the quadriceps mechanism. There is an increased risk of developing osteoarthritis in people who have broken their patella. [8]

There is limited evidence supporting the different surgical interventions for treating fractures of the patella in adults. [10] There is also no evidence of trials that could evaluate the effects of surgical treatment compared with the conservative treatment or other different types of conservative interventions. [10]

Epidemiology

Patella fractures make up about 1% of all broken bones. [6] Males are affected more often than females. [3] Those of middle age are most often affected. [3] 6% to 9% of patellar fractures are of the open type. [11] An ageing population and global increase in the number of TKAs has led to an increasing number of periprosthetic fractures of which a patella fracture is one type. [11]

History

Prior to the 19th century most patella fractures were treated non-surgically with extension splinting, frequently resulting in poorly joined fragments of bone and long-term pain and disability. [6] Incomplete understanding of the importance of the patella led to the trend of removing the whole patella, also resulting in pain, disability and dissatisfaction. [6] The first open reduction and internal fixation for a patella fracture was performed in 1877 by Scottish surgeon Sir Hector Cameron. [6] Several techniques followed and materials used included metal loops, pins, kangaroo tendons and screws. Significant advances in surgery occurred in the 1950s with the development of banding after Herbert A. Haxton and others demonstrated that the patella was not just to protect the knee but important for straightening the leg. [6] Subsequently, the three surgical treatments for displaced patella fractures became tension banding, partial patellectomy and total patellectomy, the decision of which to use tailored to the individual. [6]

Related Research Articles

Knee Region around the kneecap

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.

Patella 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.

Attenuated patella alta Medical condition

Attenuated patella alta is an extremely rare condition affecting mobility and leg strength. It is characterized by an unusually small knee cap (patella) that develops out of and above the joint. Typically, as the knee cap sits in the joint, it is stimulated to growth by abrasion from the opposing bones. When not situated properly in the joint, the knee cap does not experience such stimulation and remains small and undeveloped. Note that the cartilage under and around the kneecap is eight times smoother than ice, so "abrasion" may not be the best term.

Maisonneuve fracture Medical condition

The Maisonneuve fracture is a spiral fracture of the proximal third of the fibula associated with a tear of the distal tibiofibular syndesmosis and the interosseous membrane. There is an associated fracture of the medial malleolus or rupture of the deep deltoid ligament of the ankle. This type of injury can be difficult to detect.

Distal radius fracture Fracture of the radius bone near the wrist

A distal radius fracture, also known as wrist fracture, is a break of the part of the radius bone which is close to the wrist. Symptoms include pain, bruising, and rapid-onset swelling. The wrist may be broken for life. The ulna bone may also be broken.

Osgood–Schlatter disease Inflammation of the patellar ligament

Osgood–Schlatter disease (OSD) is inflammation of the patellar ligament at the tibial tuberosity (apophysitis). It is characterized by a painful bump just below the knee that is worse with activity and better with rest. Episodes of pain typically last a few weeks to months. One or both knees may be affected and flares may recur.

Anterior cruciate ligament reconstruction 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 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.

Patellar tendinitis Human disease

Patellar tendinitis, also known as jumper's knee, is an overuse injury of the tendon that straightens the knee. Symptoms include pain in the front of the knee. Typically the pain and tenderness is at the lower part of the kneecap, though the upper part may also be affected. Generally there is no pain when the person is at rest. Complications may include patellar tendon rupture.

Knee replacement Surgical procedure

Knee replacement, also known as knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve pain and disability, most commonly offered when joint pain is not diminished by conservative sources and also for other knee diseases such as rheumatoid arthritis and psoriatic arthritis. In patients with severe deformity from advanced rheumatoid arthritis, trauma, or long-standing osteoarthritis, the surgery may be more complicated and carry higher risk. Osteoporosis does not typically cause knee pain, deformity, or inflammation and is not a reason to perform knee replacement.

Ankle fracture Medical condition

An ankle fracture is a break of one or more of the bones that make up the ankle joint. Symptoms may include pain, swelling, bruising, and an inability to walk on the injured leg. Complications may include an associated high ankle sprain, compartment syndrome, stiffness, malunion, and post-traumatic arthritis.

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.

Patellar tendon rupture Medical condition

Patellar tendon rupture is a tear of the tendon that connects the knee cap (patella) to the tibia. Often there is sudden onset of pain and walking is difficult. In a complete rupture, the ability to extend that knee is decreased. A pop may be felt when it occurs.

Tuberosity of the tibia Slight protrusion at the top front end

The tuberosity of the tibia or tibial tuberosity or tibial tubercle is an elevation on the proximal, anterior aspect of the tibia, just below where the anterior surfaces of the lateral and medial tibial condyles end.

Quadriceps tendon

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.

Scaphoid fracture Fracture of the scaphoid bone in the wrist

A scaphoid fracture is a break of the scaphoid bone in the wrist. Symptoms generally includes pain at the base of the thumb which is worse with use of the hand. The anatomic snuffbox is generally tender and swelling may occur. Complications may include nonunion of the fracture, avascular necrosis of the proximal part of the bone, and arthritis.

Patellofemoral pain syndrome 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, excessive use, or climbing and descending stairs.

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.

Patellar dislocation 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.

Olecranon fracture Medical condition

Olecranon fracture is a fracture of the bony portion of the elbow. The injury is fairly common and often occurs following a fall or direct trauma to the elbow. The olecranon is the proximal extremity of the ulna which is articulated with the humerus bone and constitutes a part of the elbow articulation. Its location makes it vulnerable to direct trauma.

Herbert Alexander Haxton FRCS FRSE was a Scottish surgeon to the Royal Manchester Children's Hospital and the Manchester North Hospital and Crumpsall Hospital. He contributed to surgical techniques of suturing and investigated the function of the sympathetic nervous system in the sweating conditions hyperhidrosis and gustatory hyperhidrosis.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 "Patellar (Kneecap) Fractures". OrthoInfo - AAOS. January 2017. Archived from the original on 16 October 2017. Retrieved 16 October 2017.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Kakazu R, Archdeacon MT (January 2016). "Surgical Management of Patellar Fractures". The Orthopedic Clinics of North America. 47 (1): 77–83. doi:10.1016/j.ocl.2015.08.010. PMID   26614923.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 Abbasi D. "Patella Fracture - Trauma". Orthobullets.com. Archived from the original on 17 October 2017. Retrieved 16 October 2017.
  4. ↑ Melvin JS, Mehta S (April 2011). "Patellar fractures in adults". The Journal of the American Academy of Orthopaedic Surgeons. 19 (4): 198–207. doi:10.5435/00124635-201104000-00004. PMID   21464213. S2CID   34028631.
  5. 1 2 3 4 5 6 7 Lee D, Li B, Grannis S (2010). "Chapter 11: Knee". In Sueki D, Brechter J (eds.). Orthopedic Rehabilitation Clinical Advisor. Mosby Elsevier. p. 592. ISBN   978-0-323-05710-3.
  6. 1 2 3 4 5 6 7 8 9 10 11 Bedi A, Karunakar MA (2010). "52. Patella fractures and extensor mechanism injuries". In Rockwood CA, Bucholz RW, Court-Brown CM, Heckman JD, Tornetta P (eds.). Rockwood and Green's Fractures in Adults (7th ed.). Philadelphia: Lippincott Williams & Wilkins. pp. 1752–1765. ISBN   978-1-60547-677-3.
  7. 1 2 3 4 "Patella Fractures". Emergency Care Institute (ECI). Emergency Care Institute new South Wales. 1 September 2016. Retrieved 14 February 2021.
  8. 1 2 3 4 5 Wilde PG (2010). "Chapter 12: The Knee". In Foy MA, Fagg PS (eds.). Medicolegal Reporting in Orthopaedic Trauma E-Book (4th ed.). Churchill Livingstone Elsevier. pp. 279–281. ISBN   978-0-443-06833-1.
  9. ↑ Günal I, Karatosun V (August 2001). "Patellectomy: an overview with reconstructive procedures". Clinical Orthopaedics and Related Research. 389 (389): 74–78. doi:10.1097/00003086-200108000-00012. PMID   11501826.
  10. 1 2 Sayum Filho J, Lenza M, Tamaoki MJ, Matsunaga FT, Belloti JC (February 2021). "Interventions for treating fractures of the patella in adults". The Cochrane Database of Systematic Reviews. 2021 (2): CD009651. doi:10.1002/14651858.cd009651.pub3. PMC   8095054 . PMID   33625743.
  11. 1 2 Luo TD, Marino DV, Pilson H (2020). "Patella Fractures". StatPearls. Treasure Island (FL): StatPearls Publishing. Retrieved 14 February 2021.
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