Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Loose Bodies, Knee


Related Terms

  • Joint Mice

Differential Diagnosis

Specialists

  • Orthopedic (Orthopaedic) Surgeon
  • Physical Therapist
  • Radiologist

Comorbid Conditions

  • Musculoskeletal disorders
  • Rheumatologic disorders

Factors Influencing Duration

Factors include the number of loose bodies, location of the loose bodies within the knee, underlying cause, and type of treatment. Duration may be shorter for individuals with sedentary jobs.

Medical Codes

ICD-9-CM:
717.6 - Internal Derangement of Knee; Degeneration, Rupture (old), or Tear (old) of Articular Cartilage or Meniscus of Knee, Loose Body in Knee; Joint Mice, Knee; Rice Bodies, Knee (Joint)

Overview

Loose bodies are fragments of bone and/or cartilage that freely float in the joint space. They may occur singly or in groups and typically affect only one joint.

Loose bodies are classified as either stable or unstable. Stable loose bodies are in a fixed position and are generally well tolerated by the individual. Unstable loose bodies are free to move about the joint and cause symptoms.

Loose bodies are classified into three types: fibrinous, cartilaginous, and osteocartilaginous. Fibrinous loose bodies result from bleeding within the joint or from the death of the tissue lining of joints (synovial membrane) associated with tuberculosis, osteoarthritis, and rheumatoid arthritis. Cartilaginous loose bodies are fragments of cartilage and are caused by injury (trauma) to the joint and osteoarthritis. Osteocartilaginous loose bodies are fragments of cartilage and bone caused by fractures, bone and cartilage inflammation (osteochondritis dissecans), osteoarthritis, and benign tumors of the synovial membrane (synovial chondromatosis). Cartilage is nourished by the fluid within the joint (synovial fluid) so loose bodies often increase in size and become smoother over time.

Individuals with a degenerative joint disease (e.g., arthritis or osteochondritis dissecans) are more likely to develop loose bodies in the knee.

Incidence and Prevalence: Overall incidence and prevalence is unknown.

Source: Medical Disability Advisor



Causation and Known Risk Factors

Individuals who participate in sports are at risk of developing loose bodies in the knee. Loose bodies are common and affect men and women equally.

Source: Medical Disability Advisor



Diagnosis

History: The most common symptoms of loose bodies include knee pain and swelling, with intermittent locking or catching of the joint. The locking disappears spontaneously, only to recur. Individuals may report hearing a grating sound (crepitus) with joint movement. They may also report that the joint intermittently "gives way" or "goes out," causing them to fall. Any history of osteoarthritis or injury should be taken into consideration while making a diagnosis.

Physical exam: The exam may reveal tenderness, soft tissue swelling, or a grating sound in the affected joint. The affected joint may be locked (unable to fully extend). There may be evidence of fluid buildup (effusion) in the joint. Loose bodies are rarely felt by touch (palpation). A history of degenerative or post-traumatic arthritis may be significant and indicate further testing. The interior of the joint can be examined directly by arthroscopy, and if indicated, arthroscopic surgery may be performed at the same time.

Tests: Larger loose bodies are typically calcified and thus easily visible on a plain film x-ray of the affected joint. Loose bodies that are small or contain little or no bone may not be visible with an x-ray and are typically diagnosed using either CT or arthrography. MRI may be useful in determining whether associated bone changes have occurred. Ultrasound scans may be performed to determine the presence and location of loose bodies.

Source: Medical Disability Advisor



Treatment

To encourage the best possible management, whenever possible the underlying cause of loose bodies should be identified. For small loose bodies, treatment may be directed at relief of symptoms. If pain and swelling are present, analgesics or nonsteroidal anti-inflammatory medications (NSAIDs) may be prescribed. In general, any loose body that is causing symptoms should be removed.

Large loose bodies may require removal by use of an arthroscope (arthroscopy). A small suction tip may be used to help draw out the loose body, or it may be held in place by a small needle and grasped with a special tool. Some loose bodies may not be retrievable due to their position in the joint space, and an instrument (mechanical burr or resector) may be used to break the loose body apart. Once it is in small pieces, it can be easily reabsorbed through the body's normal means of elimination (enzyme degradation). Very large loose bodies and those located in the back of the knee need to be removed by open surgery (arthrotomy). Large osteocartilaginous loose bodies can be realigned (reduced) and secured using pins or screws. In some cases, such as synovial chondromatosis, part of the synovium may be removed (partial synovectomy).

Source: Medical Disability Advisor



Prognosis

This is a self-limited condition that can be successfully treated. The symptoms caused by small loose bodies can be effectively controlled by analgesics and NSAIDs, but more aggressive treatment (surgery) may be necessary. Most individuals who undergo a surgical procedure (arthroscopy, arthrotomy, synovectomy, or loose body pulverization) to treat loose bodies recover with good early results. Individuals with loose bodies in the knee are predisposed to developing osteoarthritis in the affected joint.

Source: Medical Disability Advisor



Rehabilitation

The focus of rehabilitation for loose bodies in the knee is to control pain and restore function. The rehabilitation program will depend on whether or not the individual has had surgery or has plans for surgery. The first goal is gait training with an assistive device as needed for independent ambulation, with weight bearing as indicated by the physician. Prolonged immobilization should be avoided for non-surgical cases (Miller).

Initially, if pain and edema are a problem, modalities such as heat and cold may be used (Braddom). After the initial injury or postoperative period, common clinical practice includes a heat treatment before exercise (to relax the tissues around the knee) and a cold treatment after exercise (to control the pain and swelling).

The next goal is to restore motion and strength to the involved knee. In a nonoperative knee, full range of motion may be difficult to achieve, and the joint may lock intermittently throughout the available range. Postoperatively, full range of motion should be expected. In both situations, exercise may be progressed based on the recommendations of the physician. Therapy should progress to strengthening exercises as tolerated. It may also be necessary to strengthen the muscles supporting the adjacent joints at the hip and ankle.

Therapy should include flexibility exercises throughout the period of strengthening. Although strong muscles around the joint are critical, flexibility of the same muscle groups must be considered. Generally, both open and closed kinetic chain exercises are emphasized (Hudgins).

When full, pain-free motion is regained and the individual has sufficient strength for all activities of daily living, therapy may progress to balance and proprioceptive exercises. The extent of these exercises will be determined by the physician, the individual, and the therapist. Individuals may also be instructed in a home exercise program to complement the supervised exercise regimen.

Prior to discharge from physical therapy, individuals may receive instruction emphasizing strength and flexibility exercises and joint-protective activities. The desired degree of knee loading must be considered prior to return to work and leisure activities, and these requirements should be discussed with the individual's physician. An ergonomic assessment may be indicated for those individuals whose job demands place the knees at risk for injury.

FREQUENCY OF REHABILITATION VISITS
Nonsurgical
SpecialistLoose Bodies, Knee
Physical TherapistUp to 12 visits within 8 weeks
Surgical
SpecialistLoose Bodies, Knee
Physical TherapistUp to 12 visits within 6 weeks
The table above represents a range of the usual acceptable number of visits for uncomplicated cases. It provides a framework based on the duration of tissue healing time and standard clinical practice.

Source: Medical Disability Advisor



Complications

Severe pain and swelling and potential damage to the surface of the joint (post-traumatic arthritis) or synovial lining of the joint cavity are possible complications. Long-term inflammation of the synovium (synovitis) can occur.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Before surgical treatment, the knee may abruptly give out, causing the individual to fall. Work in an area away from dangerous machinery or other hazards may be advisable. The individual may need crutches or a walking cane temporarily, so work site accessibility or relocation may be required. Standing, squatting, kneeling, crawling, and walking may need to be limited temporarily. Operating a motor vehicle or other machinery that requires use of the feet may be restricted temporarily. Company policy on medication usage should be reviewed to determine if pain medication use is compatible with job safety and function.

Source: Medical Disability Advisor



Failure to Recover

If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.

Regarding diagnosis:

  • Does individual have stable or unstable loose bodies in the knee?
  • Is individual active in sports?
  • Does individual have a history of degenerative joint disease?
  • Does individual have a history of knee pain following exercise, episodes of the knee giving way, and/or recurrent knee effusion?
  • Does individual report crepitus?
  • Has individual received adequate testing to establish the diagnosis?
  • Have conditions with similar symptoms been ruled out?

Regarding treatment:

  • Was symptomatic treatment effective?
  • Was it necessary to perform surgery?
  • Has physical therapy been prescribed?

Regarding prognosis:

  • How severe are symptoms? Are they incapacitating?
  • Are any conditions present that could affect recovery?
  • Has individual developed any complications?
  • Can individual perform normal activities of daily life?
  • Is individual active in physical therapy?

Source: Medical Disability Advisor



References

Cited

Braddom, Randolph L. Physical Medicine and Rehabilitation. 3rd ed. Philadelphia: W.B. Saunders, 2006.

Hudgins, Thomas, et al., eds. "Chapter 65 - Patellofemural Syndrome." Essentials of Physical Medicine and Rehabilitation. 2nd ed. Philadelphia: Saunders, Elsevier, 2008.

Miller, Robert H., and Frederick M. Azar. "Chapter 43 - Knee Injuries." Campbell's Operative Orthopaedics. Eds. S. Terry Canale and James H. Beaty. 11th ed. Philadelphia: Mosby Elsevier, 2008.

Source: Medical Disability Advisor






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