Patella fracture is a frequently observed knee traumatization. It is either a result of force directly exerted on the patella itself or occurs when quadriceps forcefully contract.
Presentation
The predominant symptom manifesting after a patella fracture is knee pain [7]; the patient's medical history will illustrate the way in which the traumatization was sustained: direct force, indirect force or a combination of those.
Displaced fractures usually present with abnormal appearance of the knee and the dislocated pieces may as well be palpable. Medial and lateral retinacula disruption may also be present, accompanied by hemarthrosis.
Entire Body System
- Pain
Chronic Pain Long-term pain in the front of the knee is common with patellar fractures. While the cause of this pain is not completely understood, it is likely that it is related to posttraumatic arthritis, stiffness, and muscle weakness. [orthoinfo.aaos.org]
The patient presented peripatellar pain in full knee flexion and kneeling position. We resected the ossification, and the patient was immediately relieved from pain and was mobilised under full weight bearing with no limitation of knee flexion. [ncbi.nlm.nih.gov]
Patients present with marked swelling and pain over the patella with point tenderness and marked reduction in extension strength. Usually, there is a large joint effusion or hemarthrosis. [radiopaedia.org]
- Falling
They happen during falls, eg. falls from the bicycle or motorcycle, falls after slipping on ice, but they are also common after car accidents. [videoreha.com]
These three types of patella fractures are commonly caused by the following: A Fall. Falling directly on the knee can cause a patella fracture. Falls may occur will walking, running, or participating in exercise programs or sports. [totalorthosportsmed.com]
Cause of fracture: Direct trauma: Due to its position under the skin in front of the knee, it is vulnerable to fracture with direct trauma e.g. falling directly on the knee or being hit by a car. [hip-knee.com]
One fall or continued lack of compliance with bracing can pull the bone ends apart and result in the need for surgery. Knees treated in long term braces often become quite stiff. [renoortho.com]
Complications stiffness weak extensor mechanism degenerative disease of the patellofemoral joint Etiology There are different causes of patella fracture: direct blow to patella, e.g. dashboard injury (high energy) or fall onto the patella (low energy) [radiopaedia.org]
- Swelling
Patients present with marked swelling and pain over the patella with point tenderness and marked reduction in extension strength. Usually, there is a large joint effusion or hemarthrosis. [radiopaedia.org]
Raise your knee above the level of your hips to reduce swelling. [fracturecare.co.uk]
Swelling: Swelling and bruising around the front of the knee is typical of a patella fracture. Often, as days go by, the swelling extends down the leg and even into the foot. [orthopedics.about.com]
Medicine will be needed to ease swelling and pain. Other options are: Without Surgery A mild fracture may be treated with a cast to keep the knee from moving as it heals. A brace, cane, or crutches may be needed after the cast comes off. [winchesterhospital.org]
- Weakness
Muscle Weakness Some patients may have permanent weakness of the quadriceps muscle in the front of the thigh after a fracture. Some loss of motion in the knee, including both straightening (extension) and bending (flexion), is also common. [orthoinfo.aaos.org]
Patellar fractures can lead to stiffness, extension weakness, and patellofemoral arthritis. Nonsurgical management is indicated for nondisplaced fractures with an intact extensor mechanism. [ncbi.nlm.nih.gov]
Complications stiffness weak extensor mechanism degenerative disease of the patellofemoral joint Etiology There are different causes of patella fracture: direct blow to patella, e.g. dashboard injury (high energy) or fall onto the patella (low energy) [radiopaedia.org]
- Severe Pain
Degenerative arthritis often develops after severely comminuted fractures. [aci.health.nsw.gov.au]
Signs of a Patella Fracture Patella fractures can cause severe pain and difficulty walking. Some of the more common symptoms of this injury include: Pain: Patella fractures are generally quite uncomfortable. [orthopedics.about.com]
Patella Fracture Signs & Symptoms Severe pain is instantly felt on the knee area. The condition will also cause the knee to immediately swell, which in turn will make it unlikely for the footballer to bend the injured knee. [footballrescue.com]
Symptoms may include: Severe pain in and around the kneecap Swelling Pain when moving the knee in both directions Difficulty extending the leg or doing a straight-leg raise A deformed appearance of the knee due to the fractured pieces Tenderness when [cedars-sinai.edu]
Respiratoric
- Aspiration
If there is an effusion at the knee and aspiration reveals hematoma with fat droplets inside, suspicion should rise about an osteochondral fracture even if nothing is detected on the radiographs in AP and lateral projections. [casesjournal.biomedcentral.com]
A potentially impaired joint can be aspirated, which will help diagnose hemarthrosis or a joint effusion; the latter leads to the aspiration of fluid containing fat globules. [symptoma.com]
[…] pt's ability to maintain knee extended against gravity; - there should be minimal displacement of fragments (2-3 mm) - minimal disruption of the articular surface (2-3 mm) - transverse undisplaced fracture of the patella is an avulsion frx; - should aspirate [wheelessonline.com]
Aspiration of the hemarthrosis and instillation of local anesthetic will the diagnostic usefulness of this test. A thorough examination of the ipsilateral extremity should ensue to evaluate for associated injury. [orthopaedicsone.com]
Gastrointestinal
- Nausea
Patients from the two groups showed no significant difference in visible analog scales at rest and during movement, fentanyl consumption, nausea, and vomiting. [ncbi.nlm.nih.gov]
Following the order will assist to overcome any nausea and vomiting. Although you may find a cold therapy unit as an optional choice, it can further help to lessen the pain involved and as well as swelling. [hydroactive.ca]
Cardiovascular
- Thrombosis
Post-operative care will include standard-of-care antibiotics and deep vein thrombosis (DVT) prophylaxis, both prescribed at the discretion of the attending surgeon. [clinicaltrials.gov]
A prospective randomized controlled trial ... 514 Tradeoff between bleeding and stent thrombosis in different dual antiplatelet therapy regimes: ... Jeger Raban V RV University Hospital Basel, Basel, Switzerland. [biomedsearch.com]
[…] blood vessels of the knee Abnormal pressure build-up within the muscles of the knee that reduces blood flow, preventing oxygen and nourishment from reaching the nerve and muscle cells (termed as compartment syndrome) Formation of blood clots (deep vein thrombosis [dovemed.com]
Eyes
- Visual Impairment
ELDERLY, NOT FEEBLE IN BEVERLY HILLS DEAR NOT FEEBLE: Your question applies not only to older people, but also to people who are visually impaired. [newspapers.com]
I slipped on ADA truncated dome tactile tile (nobby inset tiles that are used in public places so that the visually impaired will know they are approaching traffic). http://www.armor-tile.com/articles_docs4/Tactile-tile-visually-impaired.html My patella [kneeguru.co.uk]
Electronic address: - - 2014 Optic neuritis is an important pediatric disorder causing visual impairment. [biomedsearch.com]
Skin
- Ulcer
Also talk with your provider if you’ve had a stomach ulcer or gastrointestinal bleeding. Your healthcare provider may tell you to do strengthening exercises once you can put weight on the injured leg. The exercises will limit bone and muscle loss. [fairview.org]
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Talk with your provider before using these medicines if you have heart disease, high blood pressure, kidney disease, liver disease, or have had stomach ulcers or internal bleeding in the past. [nlm.nih.gov]
Also, plaster of Paris casts can result in cutaneous complications including macerations, ulcerations, infections, rashes, itching, burns, and allergic contact dermatitis, which may also be due to the presence of formaldehyde within the plaster bandages [en.wikipedia.org]
Musculoskeletal
- Fracture
fracture of mid patella (most common) comminuted fracture vertical fracture (rare) osteochondral defect usually from medial facet patellar sleeve fracture in children Some fractures are more subtle and need to be differentiated from normal variants. [radiopaedia.org]
Using a novel Arthrex ® technique, the Patella Fracture System is utilized in repairing a patella fracture. [arthrex.com]
Discussion Patients who sustain inferior pole patella fractures have limited options for fracture fixation. [ncbi.nlm.nih.gov]
This involves drilling the wires through the fracture site prior to reduction. Once the wires are passed through the fracture, the wire end nearest the fracture surface is made flush with the fracture. [emedicine.medscape.com]
- Knee Pain
In this confusing presentation, a high index of suspicion for patella fracture should be maintained for patients with knee pain and osteoporosis on x-ray with a dysplastic syndrome. [ncbi.nlm.nih.gov]
Patellofemoral syndrome; Chondromalacia patella; Runner's knee; Patellar tendinitis; Jumper's knee Anterior knee pain is pain that occurs at the front and center of the knee. [mountsinai.org]
A 9-year-old girl presented with knee pain and inability to extend her leg after landing on her flexed right knee while jumping on a trampoline. [nejm.org]
Knee pain following a Patella fracture is quite common, even after the fracture has healed. Many people find that a Knee Brace or Support helps to provide warmth and alleviates their knee pain symptoms. [physioroom.com]
- Anterior Knee Pain
Patellofemoral syndrome; Chondromalacia patella; Runner's knee; Patellar tendinitis; Jumper's knee Anterior knee pain is pain that occurs at the front and center of the knee. [mountsinai.org]
Pain, swelling and knee deformity. [radiopaedia.org]
From the time of the original fixation she had experienced mild persistent anterior knee pain, with a reduced range of motion and grinding. She had been discharged from further follow up. [bjmp.org]
- Joint Effusion
Usually, there is a large joint effusion or hemarthrosis. [radiopaedia.org]
effusion (haemarthrosis or lipohaemarthrosis) in the context of trauma is a helpful indicator of a fracture Knee - Patellar dislocation - AP Hover on/off image to show/hide findings Tap on/off image to show/hide findings Knee - Patellar dislocation - [radiologymasterclass.co.uk]
- Contusion
DOCTOR EXAMINATION deformity swelling contusion 8. INVESTIGATIONS 9. [slideshare.net]
[…] avulsion of the inferior pole of the patella If the x-ray beam is oriented horizontally and image is obtained cross-table, a fat-fluid level ( lipohemarthrosis ) may be present CT is used when a fracture is suspected but not visible MRI can show bone contusions [learningradiology.com]
Traumatic dislocation of the patella (seen in the image below) may result in patellar fracture, medial retinaculum damage, lateral femoral condyle contusion, and effusion. [emedicine.medscape.com]
A MRI may be used to show bone contusions and injuries to nearby muscles and tendons. Causes of Patella Fractures The most common cause of a patella fracture is a fall onto the kneecap, often in a slip and fall accident or staircase fall. [ebtrialattorneys.com]
Abrasions, contusion over the anterior aspect of the knee, or both may be present Examination reveals effusion of knee in a closed fracture. [boneandspine.com]
Neurologic
- Confusion
In this confusing presentation, a high index of suspicion for patella fracture should be maintained for patients with knee pain and osteoporosis on x-ray with a dysplastic syndrome. [ncbi.nlm.nih.gov]
Oblique view AP view Sunrise view Fractures of the patella can be confused with bipartite or multipartite patella. The radiographs below show bipartite patella. Compare the images below with those shown above. [med-ed.virginia.edu]
Differential Diagnosis 3.1 Knee diagnoses 3.1.1 Acute knee injury 3.1.2 Nontraumatic/Subacute 4 Evaluation 4.1 Imaging 5 Management 6 Disposition 7 See Also 8 References Background Occurs via direct blow or forceful contraction of quadriceps muscle Do not confuse [wikem.org]
[…] associated injuries: - PCL tear: - ref: Concomitant posterior cruciate ligament injuries with direct injury-related patellar fractures - Radiographs: - AP view: - patella may be difficult to see on AP view; - peripheral fractures (osteochondral frx) may be confused [wheelessonline.com]
Inferior pole fractures can be confused with Sinding Larsen Johanson disorder. (Grogen 1990) Classification Sleeve fractures can be classified by the direction of force acting on the patella into medial, lateral, superior and inferior. [posna.org]
- Unable to Walk
Diagnosis: The patient is usually unable to extend the knee fully against resistance and is unable to walk. Bruising and swelling occurs on the front of the knee. [hip-knee.com]
[…] to walk.[1] Complications may include injury to the tibia, femur, or knee ligaments.[2] 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 [en.wikipedia.org]
The patient will be unable to walk with a broken knee cap or put weight on or lift the knee area, although the ankle and toes can normally be moved as usual, except if there is injury to the neuro-vascular system in addition to the knee cap. [ctikneebraces.co.uk]
- Excitement
[Full Text HTML] [Full Text PDF] [XML] [rate_this_page] Dear Reader, We are very excited about New Features in JOCR. [jocr.co.in]
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But to be honest I am very excited about my progress thus far. My surgery was on December 22 of 2008. I, actually, drove 10 days later but now know I shouldn't have. [kneeguru.co.uk]
- Stroke
However, there are no ... 516 Clinically significant fatigue after stroke: A longitudinal cohort study. Duncan Fiona F Geriatric Medicine, University of Edinburgh, - - 2014 Fatigue is often distressing for stroke survivors. [biomedsearch.com]
[…] variety of diagnoses and treatment needs related to brain injury, cancer, cardiac and pulmonary conditions, chronic neurological conditions, limb loss, orthopedic and musculoskeletal conditions, pediatric conditions and injuries, spinal cord injury, and stroke [nyulmc-rehab.med.nyu.edu]
Workup
A patella fracture usually manifests with intense knee pain and a medical history involving a direct blow to the kneecap, an indirect strain, such as the one sustained by a fall, or a combination of these forces. Dislodged bone may be observable with a bare eye, especially in the cases of open fractures.
The first step towards evaluating a potential patella fracture is radiographic imaging. X-rays obtained from a lateral, anteroposterior and axial perspective are widely used to provide critical information about the skeletal structures underneath tissue. Radiographic depiction assesses the direction of the fracture, its type, possible comminution and other important features. Magnetic Resonance Imaging helps to evaluate osteochondral fractures, sleeve fractures [8] and generally fractures that prove difficult to characterize with other than MRI examinations.
A patient also needs to be evaluated for the presence of hemarthrosis and damage to the extensor mechanism, namely the medial and lateral retinacula. A potentially impaired joint can be aspirated, which will help diagnose hemarthrosis or a joint effusion; the latter leads to the aspiration of fluid containing fat globules. Lidocaine can be administered intra-articularly, in order to reduce the pain and allow for a more extensive examination of the patient's ability to extend the knee against gravity.
Treatment
Fractures that do not involve displacement respond to conservative treatment at a rate of nearly 90%. The patient does not benefit from any surgical intervention and is treated with a cylinder cast that is kept for 4 to six weeks, depending on the specific characteristics of the fracture. An assessment is carried out after the initial period has passed and is sign of healing are evident, the cast is removed and the patient is required to use a removable brace. the decision of cast discontinuation is based on the results of the clinical examination (painless knee, even when palpated) and radiologic findings which are compatible with union.
Gradual strengthening of the arthrosis should be attempted alongside physiotherapy to restore the range of movement. A patient can stop using a removable brace when they are able to flex their knee joint over 90 degrees and raise their leg freely against gravity.
Fractures that involve displacement do not benefit from conservative treatment and require surgical intervention instead. The precise technique is decided depending on the particular characteristics of each fracture and greatly depends on whether it is an open fracture, if arthrotomy has been sustained and if ligaments will have to be repaired as well. At any case, a thorough examination and detection of the damage is mandatory before deciding upon the best surgical treatment. A widely used surgical technique generally involves the conversion of tensile force into a compressive one, with the use of a tension band, thereby helping the patella to regain continuity faster [9] [10]. Open fractures are operated as an emergency condition.
Antimicrobial treatment is also administered prophylactically before a patella reconstructive surgery. In a case of open wound, further antibiotics are introduced into the therapeutic scheme. Tetanus shots are also mandatory if a wound is open. An orthopedic surgeon should always consider the possibility of infection before proceeding to surgery and treat it appropriately.
Prognosis
Surgical intervention is expected to result in a successful repair of patella continuity and functionality. The more extensive the damage sustained by the structure, the more time it will require to reach a stage of complete recovery; even less severe traumatizations can result in significant complications, such as patellofemoral arthrosis [5]. 10-20% of the patients who undergo open reduction internal fixation also experience displacement of the patella segments following surgery, which is believed to be the case when the separated parts are not fixed together properly by a surgeon [6]. Hardware prominence is also possible in some cases.
Etiology
In general, the patella is an anatomical structure that is susceptible to injuries, due to the fact that it is located subcutaneously and is therefore not as protected from extreme forces as other structures are. There are three possible causes of a patella fracture:
- Direct force
- Abrupt tensile force
- A combination of the above
Direct force exerted on the patella usually produces a comminuted fracture, as the regional anatomical structures are obliged to absorb the force. This may result in the traumatization not only of the patella, but of the cartilage and femoral condyles as well.
Should the patella sustain tensile-type force, such as the type sustained when the quadriceps contact violently in hyperflexion, the most common fracture acquired is a nondisplaced fracture. Lastly, if the traumatization is a result of the two forces combined, fractures of various types can occur, i.e. tansverse, displaced fractures that become comminuted at a later stage.
Epidemiology
Patella fractures represent 1% of all traumatizations sustained by the skeleton.
Pathophysiology
The patella is a small triangular bone which covers the joint between the femoral bone and tibia. The conjoined tendons of the four quadriceps muscles, known as the quadriceps tendon encases the structure and assumes the function of the patella tendon. The forces sustained by the patella when the quadriceps muscles contact are able to strain the former at such an extent that an indirect fracture can occur.
The vastus medialis is one of the four quadriceps muscles of the thigh, which function in unison. Its tendon is extended to form the medial patellar retinaculum, which is itself linked to the upper-and-towards-the-midline part of the patella. Respectively, the lateral patellar retinaculum is formed by the last part of the vastus lateralis and is also attached to the patella. The lateral and medial retinacula are responsible for a person's ability to flex the knee, an ability that is preserved if both structures are unharmed after an injury.
Patella fractures are a result of direct forces exerted on the patella or indirect forces induced by the surrounding tendons. Typically, indirect fractures are a result of abnormal or excessive knee flexion. If a major fall occurs for example, the joint is forced to absorb great pressure, which will result either in the rupture of the tendons or in a transverse patella fracture [2]. Displacement is a frequent finding is these types of fractures, whereas direct traumatization induces a comminuted fracture, articular traumatization and, most likely, open fractures [3]. Both types of forces may be exerted, which cause bone displacement alongside tissue traumas.
Regarding the regional perfusion, the three largest branches of the geniculate artery are responsible for providing the knee with the required volume of blood. Since the superior and inferior medial geniculate arteries penetrate the knee joint, a patella fracture may severely compromise the knee blood supply, leading to an avascular necrosis [4].
Prevention
In order to prevent a patella fracture, one should regularly exercise, giving emphasis to the strengthening of the knees: surrounding muscles are able to protect the patella if a person maintains good physical status. Suitable protection like kneepads are required, if one participated in a sport likely to cause knee injuries.
Summary
The patella bone is otherwise known as the "kneecap" bone. It is a structure located in the front part of the joint of the knee, at the point where the femoral bone and the tibia are joined together. The joint itself alongside the part of the patella that lies above it are enclosed by the articular cartilage, which lubricates the structures in order to allow for smoother motion, minimal friction and damage to the bones.
The patella can sustain various types of fractures. Depending on their morphology, primary patella fractures are divided in transverse, vertical, osteochondral, sleeve and marginal [1], with the fracture located at the top, lower part or center of the patella.
Depending on the severity of the fracture, it can be stable, displaced, comminuted or open. Stable fractures are those whereby the two separated parts remain in place and correct alignment. In a displaced fracture, alignment is impaired and surgical intervention is necessary before the bone starts to heal. On the other hand, comminuted fractures involve shattering of the patella into 3 pieces or more. Finally, open fractures are the severer type: the bone has torn out of the skin and adjacent structures have also sustained massive damage.
Patient Information
A patella fracture is an injury to the patella, commonly known as the kneecap. A fracture can have various degrees of severity and may also be accompanied by damage to the surrounding ligaments, muscles and tendons.
Patellar fractures are sustained in three different ways. the first one involves a direct blow to the patella, usually forceful. the second one is an indirect mechanism, whereby the patella is injured when the thigh muscles contract very violently; the quadriceps (thigh muscles) are connected to the kneecap, so their abrupt and violent contraction strains the patella to such an extent, that a fracture can occur. This can happen when falling from a considerable height. The third mechanism involves a combination of the two aforementioned ways.
Typical symptoms include knee pain, regional tenderness and swelling, knee bruises, inability to extend ones knee, defects visible with a bare eye (bone protruding, dislodged patellar pieces) and numbness. A patella fracture is diagnosed with the help of an x-ray obtained at different angles, possibly an MRI and a thorough physical examination.
Patella fractures may be treated both surgically and non-surgically, depending on the case. Generally, fractures where the patella has broken but all the damage is minimal and the segments still remain in their original place does not need surgery. The patient initially wears a cast for 1-1.5 month and then, if recovery is proceeding, discontinues the cast use and starts to wear a removable brace. Gradually, a person regains their ability to flex the knee and perform a fully-ranged knee motion. Fractures where the bone segments are out of place need to be operated on, in order to reconstruct the patella or remove some of the pieces that cannot be placed in their right position.
Antibiotic treatment is administered before and shortly after surgery, in cases of bone exposed through the skin, or, generally, when infection is clinically evident.
References
- Moretti B, Speciale D, Garofalo R, et al. Spontaneous bilateral fracture of patella. Geriatr Gerontol Int. 2008 Mar; 8(1):55-8.
- Harris RM. Fractures of the patella and injuries to the extensor mechanism. In: Bucholz, RW, Heckman, JD, Court-Brown CM, eds. Fractures in Adults. Ed 6. Philadelphia, PA: Lippincott Williams and Wilkins; 2006; 1969–1998.
- Carpenter JE, Kasman R, Matthews LS. Fractures of the patella. Instr Course Lect. 1994; 43:97–108.
- Harris, RM. Fracture of the patella. In: Rockwood and Green's Fractures in Adults, Bucholz, RW, Heckman, JD (Eds), Lippincott Williams & Wilkins, Philadelphia 2002; p.1775.
- Sorensen KH. The late prognosis after fracture of the patella. Acta Orthop Scand. 1964; 34:198–212.
- Nummi J. Fracture of the patella: a clinical study of 707 patellar fractures. Ann Chir Gynaecol Fenn Suppl. 1971; 179:1–85.
- Goldberg VM, Figgie HE, Inglis AE, et al. Patellar fracture type and prognosis in condylar total knee arthroplasty. Clin Orthop Relat Res. 1988 Nov; (236):115-22.
- von Engelhardt LV, Raddatz M, Bouillon B, et al. How reliable is MRI in diagnosing cartilaginous lesions in patients with first and recurrent lateral patellar dislocations?. BMC Musculoskelet Disord. 2010 Jul 5; 11:149.
- Berg EE. Open reduction internal fixation of displaced transverse patella fractures with figure-eight wiring through parallel cannulated compression screws. J Orthop Trauma. 1997 Nov; 11(8):573-6.
- Fortis AP, Milis Z, Kostopoulos V, et al. Experimental investigation of the tension band in fractures of the patella. Injury. 2002 Jul; 33(6):489-93.