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.

Patella Chondromalacia

patella chondromalacia in Deutsch (Deutschland)

Related Terms

  • Anterior Knee Pain
  • Chondromalacia Patellae
  • Patellofemoral Syndrome

Differential Diagnosis

Specialists

  • Orthopedic (Orthopaedic) Surgeon
  • Physiatrist (Physical Medicine and Rehabilitation Specialist)
  • Physical Therapist
  • Sports Medicine Physician

Comorbid Conditions

Factors Influencing Duration

Severity of symptoms and severity of cartilage damage are the main factors influencing length of disability. In milder cases, the ability to modify work requirements and compliance with a physical therapy program should serve to shorten the length of disability. More severe cartilage damage and symptoms that do not respond to conservative treatment are indications for surgery, leading to longer periods of disability.

Medical Codes

ICD-9-CM:
717.7 - Internal Derangement of Knee; Degeneration, Rupture (old), or Tear (old) of Articular Cartilage or Meniscus of Knee, Patella Chondromalacia; Degeneration [Softening] of Articular Cartilage of Patella

Overview

© Reed Group
Chondromalacia of the patella is a condition in which the cartilage of the kneecap (patella) becomes worn from age or is damaged from injury. In a healthy knee, the undersurface of the patella is covered with articular cartilage that is smooth and slick. This surface allows the patella to slide easily in the groove of the femur as the knee bends and straightens (flexes, extends). With chondromalacia patella, the undersurface of the patella becomes rough and then wears away (thins). This loss or damage of articular cartilage is an early finding in osteoarthritis. Chondromalacia patella is thus an arthritis involvement of the patella.

Some individuals are born with natural anatomic variations that make them more prone to developing chondromalacia patella. Chondromalacia may also be caused by trauma, such as a twisting injury in which the patella is pulled out of the femoral groove and the cartilage surface is bruised, scratched, or chipped. Individuals who have previously had a fracture or dislocation of the patella are more prone to develop chondromalacia patella. Most cases of chondromalacia patella develop from our upright posture that stresses the patellofemoral joint. It is most often a wear and tear condition rather than a specific injury.

Incidence and Prevalence: Knee pain is reported by about 20% of adult Americans and accounts for nearly 3 million outpatient and emergency room visits in the US annually (Levy). Chondromalacia patella may be the source of the knee pain, but it more frequently is seen concomitantly with other conditions.

Source: Medical Disability Advisor



Causation and Known Risk Factors

Chondromalacia patella is a condition that tends to affect teenagers (especially females) and individuals over 40 years of age (Tidy). Certain sports (e.g., football, soccer, running, sailing, fencing) are also commonly associated with this disorder.

Source: Medical Disability Advisor



Diagnosis

History: Individuals may complain of knee pain with walking, running, squatting, and ascending or descending stairs. However, knee pain is not always present, and is not an indicator of the severity of chondromalacia patella. The individual may report a feeling of grating, catching, or locking of the knee with motion. Some individuals will have a sensation that the knee is giving out. Many individuals report pain after sitting with the knee bent for long periods (e.g., during movies, car rides, plane trips).

Physical exam: Chondromalacia patella may be evaluated by placing manual pressure on the patella while the individual contracts the quadriceps muscle. Pain during this maneuver is suggestive of chondromalacia patella. A crackling sound in the knee (crepitus) is often noticeable with passive range of motion (PROM). Active range of motion (AROM) against resistance is usually painful. Alignment of the patella may be evaluated by measuring the quadriceps angle (Q-angle) although this is difficult to interpret.

Tests: Routine knee x-rays will include special views of the patella (Merchant view) to evaluate its position in the femoral groove. MRI or CT scans can be used to evaluate the articular surface.

Source: Medical Disability Advisor



Treatment

Nonsurgical (conservative) treatment involves rest and decreasing the frequency of activities that aggravate the condition, such as squatting, ascending or descending stairs, kneeling, lunging, and sitting with bent knees. Use of oral and topical nonsteroidal anti-inflammatory medications (NSAIDs) and cold therapy (cryotherapy) followed by heat packs (thermotherapy) may provide relief of pain and swelling. In some cases, shoe orthotics or a brace to stabilize the patella may be recommended as both treatment and prevention. Taping or bandaging of the affected knee may provide some pain relief.

Physical therapy to increase quadriceps strength and decrease swelling and pain may be helpful. Patient education is an important part of treatment because chondromalacia patella is a chronic condition.

For severe cases in which symptoms do not respond to conservative treatment, arthroscopic surgery may be recommended to smooth (débride) the undersurface of the patella. This procedure involves removing (shaving) the damaged cartilage down to the less damaged cartilage underneath. In more severe cases, the damaged cartilage may be removed entirely (chondrectomy); however, these procedures on the damaged cartilage rarely produce lasting beneficial results. If the problem is aggravated by malalignment of the patella, various surgical procedures can be performed to realign the patella and relieve pressure on the cartilage surface. These include tightening of the medial capsule of the knee and lateral capsular release to relieve excessive tightness of the lateral capsule. In very severe cases patellectomy, patella arthroplasty with patella replacement, total knee replacement, or tibial osteotomy to displace the patella anteriorly (Maquet or Fulkerson procedure) may be indicated.

Source: Medical Disability Advisor



ACOEM

ACOEM's Practice Guidelines, the gold standard in effective medical treatment of occupational injuries and illnesses, are provided in this section to complement the disability duration guidelines.*
 
Knee Disorders
 
* The relationship between the MDGuidelines (MDA) content and ACOEM's guidelines is approximate and does not always link identical diagnoses. The user should consult the diagnostic codes in both guidelines, as well as the clinical descriptions, before assuming an equivalence.

Source: ACOEM Practice Guidelines



Prognosis

Acute, painful episodes usually resolve with rest and a period of avoidance of aggravating activities. Complete resolution of symptoms is rare.

In severe cases in which surgery is required, outcome depends on the severity of the cartilage damage and the type of surgery performed. Individuals who undergo a full patellectomy usually experience persistent weakness of the knee. Individuals who undergo insertion of a patellar prosthesis may eventually experience wearing of the opposing articular surface of the femur, causing further symptoms. This procedure is still being refined and final results are not known. Total knee replacement is more aggressive but gives satisfactory results in more than 80% of cases (Palmer). The outcomes for the Maquet and Fulkerson procedures are variable.

Source: Medical Disability Advisor



Rehabilitation

The aim of rehabilitation for patellar chondromalacia is to control symptoms and increase function. Rehabilitation of the knee will vary depending on the underlying origins and causes (etiology) of the excess pressure on the undersurface of the patella.

In general, rehabilitation of patellar chondromalacia focuses on stretching tight structures, strengthening the knee musculature, and on proprioceptive exercises. If knee mobility is limited by pain, the physical therapist may initially use modalities, such as electrical stimulation and cold, for pain control.

Once pain has decreased, the individual may progress with an exercise program. Quadriceps stretches become a vital part of the recovery program because of the force this muscle group exerts on the patella (Hudgins); stretches for hip flexors, hamstrings, calf muscles, and iliotibial bands may also help reduce abnormal forces on the patellofemoral joint, if tight (Hudgins). Strengthening exercises should be included, including open and closed chain activities, which appear to be equally effective and may provide pain relief (Hudgins; Heintjes). However, closed chain exercises are less stressful to the patellofemoral joint between 0 to 45 degrees of knee flexion, and thus may be more commonly used during the acute phase of rehabilitation (Hudgins). Patellar bracing or taping is frequently included (Fulkerson). Foot orthotics may also be used although there is no evidence regarding which type may be more beneficial (Collins; D’hondt).

Individuals should be instructed in a home exercise program to complement the supervised rehabilitation program and to be continued after discharge from therapy.

FREQUENCY OF REHABILITATION VISITS
Nonsurgical
SpecialistPatella Chondromalacia
Physical TherapistUp to 12 visits within 6 weeks
Surgical
SpecialistPatella Chondromalacia
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

The most common complication is continued discomfort; this may persist with or without surgical intervention.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Individuals whose job requirements include frequent or prolonged periods of walking, lifting or carrying heavy items, ascending and descending stairs or ramps, or squatting may need to restrict or eliminate these activities until symptoms subside. Until pain subsides, individuals should be allowed frequent rest breaks to avoid prolonged standing. The work environment may need to be modified to permit sitting with the knee in extension rather than in flexion. Depending upon the type of surgery performed, the individual may be treated as an outpatient and may return to work within a few days, or, with more involved surgeries, the individual may require 1 to 2 nights in the hospital and a more extended break from work.

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:

  • Has diagnosis of patella chondromalacia been confirmed?
  • Has an x-ray or CT scan been done to assess patellar alignment?
  • Has a bone scan been done to rule out other diagnoses?
  • Has individual experienced any aggravating conditions such as patella malalignment, recurrent patella subluxation, dislocation, or osteoarthritis?
  • Does individual have an underlying condition that may affect recovery?

Regarding treatment:

  • Were conservative methods effective in resolving symptoms?
  • Did the individual receive sufficient physical therapy?
  • Is the individual compliant in following an exercise program to strengthen the quadriceps muscle?
  • Has a 6-month period of conservative therapy been unsuccessful?
  • Was surgical intervention required? If so, what procedure was performed?

Regarding prognosis:

  • If a 6-month period of conservative therapy been unsuccessful, could symptoms be expected to resolve with additional time and therapy?
  • If surgical intervention was required, did procedure achieve expected results?
  • Have symptoms recurred?
  • Have other problems occurred as a result of the procedure?
  • What further treatment options are available?

Source: Medical Disability Advisor



References

Cited

Collins, N., et al., eds. "Foot orthoses and physiotherapy in the treatment of patello femoral pain syndrome: randomized clinical trial." BMJ Clinical Evidence Handbook: Musculoskeletal disorders. BMJ Publishing Group, 2007. 1-8.

D'hondt, N. E., et al. "Orthotic Devices for Treating Patellofemoral Pain Syndrome." Cochrane Database of Systematic Reviews 2 (2002): CD002267. National Center for Biotechnology Information. National Library of Medicine. 21 Jan. 2009 <PMID: 12076444>.

Fulkerson, J., ed. "Diagnosis and treatment of patients with patellorfemoral pain." American Journal of Sports Medicine 30 3 447-456.

Heintjes, E., et al. "Exercise Therapy for Patellofemoral Pain Syndrome." Cochrane Database of Systematic Reviews 4 (2003): CD003472. National Center for Biotechnology Information. National Library of Medicine. 21 Jan. 2009 <PMID: 14583980>.

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

Levy, David, Howard Dickey-White, and June Sanson. "Knee Injury, Soft Tissue." eMedicine. Eds. Eric Kardon, et al. 12 Dec. 2008. Medscape. 18 Feb. 2009 <http://emedicine.medscape.com/article/826792-overview>.

Palmer, Simon H., and Mervyn J. Cross. "Total Knee Arthroplasty." eMedicine. Eds. Francisco Talavera, et al. 30 Jan. 2008. Medscape. 18 Feb. 2009 <http://emedicine.medscape.com/article/1250275-overview>.

Servi, Jane T. "Patellofemoral Joint Syndromes." eMedicine. Eds. Andrew L. Sherman, et al. 22 May. 2008. Medscape. 18 Feb. 2009 <http://emedicine.medscape.com/article/90286-overview>.

Tidy, Colin. "Chondromalacia Patellae." PatientUK. 3 Oct. 2008. 18 Feb. 2009 <http://www.patient.co.uk/showdoc/40024870/>.

Source: Medical Disability Advisor






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