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.

Malunion and Nonunion of Fracture


Related Terms

  • Fracture Deformity
  • Nonjoining Fracture

Differential Diagnosis

Specialists

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

Comorbid Conditions

Factors Influencing Duration

Functional difficulty and duration of disability depend on the site and severity of fracture and whether the fracture is a malunion or nonunion.

Medical Codes

ICD-9-CM:
733.81 - Malunion of Fracture
733.82 - Nonunion of Fracture, Psedoarthrosis (Bone)

Overview

© Reed Group
A malunion is a broken (fractured) bone that has healed in an unacceptable position that causes significant impairment. A nonunion is a fracture that has failed to heal after several months.

In malunion, the bone may have healed at a bent angle (angulated), may be rotated out of position, or the fractured ends may be overlapped causing bone shortening. Malunion may be caused by inadequate immobilization of the fracture, misalignment at the time of immobilization, or premature removal of the cast or other immobilizer.

Nonunion has several causes. The broken ends of bone may be separated too much (overdistraction), which can occur if excess traction was applied. There could have been excessive motion at the fracture site, either from inadequate immobilization after the injury or from having a cast removed prematurely. Muscle or other tissue caught between the fracture fragments also can prevent healing, as can the presence of infection or inadequate blood supply to the fracture site. Bone disease (e.g., bone cancer) also can prevent healing.

There are two types of nonunions: fibrous nonunion and false joint (pseudarthrosis). Fibrous nonunion refers to fractures that have healed by forming fibrous tissue rather than new bone. Pseudarthrosis refers to nonunions in which continuous movement of the fracture fragments has led to the development of a false joint. Certain types of fractures are associated with a high risk of nonunion, such as fractures of the wrist (carpus), including scaphoid bone; certain fractures of the foot, including navicular fractures and Jones (diaphyseal) fractures of the fifth metatarsal; shoulder long bone fractures (proximal humerus fractures); and some shin bone (tibial) fractures.

The severity of the injury is a strong factor in the healing process. Individuals who have had a severe traumatic fracture, large displacement between fracture fragments, and fractures where the bone was broken into many pieces (comminuted fracture) are at an increased risk of nonunion. Open or compound fractures also are at risk of malunion or nonunion. A condition called compartment syndrome can occur when severe trauma leads to such a degree of swelling that the blood supply is compromised. The result is muscle death around the fracture site and inadequate bone repair.

Incidence and Prevalence: Scaphoid fractures are the most common hand fracture and heal with a nonunion in 10% to 15% of individuals (Boles). Fractures of the fingers (phalanges) that undergo surgical correction proceed to malunion in 9% of individuals and to nonunion in 6% (Van Oosterom 108).

Nearly 8% of tibial shaft fractures heal with malunion that results in limb deformity (Milner 971). Between 2% and 10% of fractures of the tibia result in nonunion (Patel).

Following surgery (open reduction with internal fixation, ORIF) to repair displaced hip fractures of the femoral neck, 10% of individuals develop a nonunion (Stannard 560).

More than 6% of fractures of the collar bone (clavicle) that are treated nonoperatively result in a nonunion (Robinson 1359).

In general, nonunions occur in 1.1% of shoulder joint fractures of the proximal humerus, although if there is slippage of the bone ends while healing, prevalence may reach 33% to 100% (Court-Brown 1517).

Source: Medical Disability Advisor



Causation and Known Risk Factors

Certain lifestyle and health factors may interfere with bone healing. These include smoking, excessive alcohol use, poor nutritional status, poor general health, fitness deficits, and diabetes. Other factors contribute to loss of bone strength and make healing more difficult. These include use of nonsteroidal anti-inflammatory drugs (NSAIDs), use of corticosteroid drugs, other drugs such as anticonvulsants, and the thyroid hormone replacement, thyroxine. Individuals of European or Asian ancestry who have increased risk for osteoporosis and elderly individuals are at increased risk for poor bone healing. Women who have experienced early menopause, late menarche, or the loss of their ovaries, are at increased risk for bone weakness.

Source: Medical Disability Advisor



Diagnosis

History: History is of a fracture that may or may not have been treated by a physician. The individual may report pain, swelling (edema), instability, or deformity at the site of a previously broken bone. If the fracture was in a lower extremity, the individual may report difficulty bearing weight through the limb.

Physical exam: The exam reveals the deformity of a malunion or the instability of a nonunion. Touching with the hands (palpation) may reveal tenderness.

Tests: Plain x-rays demonstrate the fracture malunion or nonunion. CT scan, MRI, or bone scan may help further define the condition.

Source: Medical Disability Advisor



Treatment

Most malunions and nonunions require open surgery to realign the fracture fragments into their normal anatomical position (open reduction) and stabilize the fracture by use of metal plates, rods, screws, and / or wires (internal fixation). Bone graft material may be placed in the surgical site to stimulate fracture healing. Some cases, whether treated surgically or with noninvasive techniques (closed reduction), benefit from the use of electrical, electromagnetic, or ultrasonic stimulation to promote fracture healing and bone growth. Electrical stimulation may be administered by a self-contained device surgically implanted internally at the fracture site or by multiple electrodes placed over the skin near the fracture site. In some studies of fractures of the radius, lateral malleolus, and tibia, low-intensity pulsed ultrasound treatments administered through the skin adjacent to the fracture site have been shown to speed healing (Mundi 132).

Malunion is treated by surgically breaking the malunion (osteotomy), followed by ORIF. Infection requires surgical removal of any infected bone or tissue (débridement), followed by intensive antibiotic treatment.

Treatment of nonunion may be complemented with a synthetic bone graft or one that is obtained from the individual (autograft, autogenous graft), from another individual (allograft, homogeneous graft), or from an animal (xenograft, heterogeneous graft). Newer approaches are using recombinant bone morphogenic protein and bone marrow aspirates. Bone marrow may be harvested from the individual's hip bone (iliac crest) and injected directly into the fracture site guided by external imaging (fluoroscopy). Treatment of pseudarthrosis involves removal (resection) of the false joint tissue before placement of the bone graft. Treatment of delayed unions and nonunions may also include functional bracing of the fracture site.

In some instances (e.g., some fractures of scaphoid), nonunion causes only slight problems, and the condition is left untreated. Likewise, malunion may be left untreated if it causes little or no functional deficit. For example, clavicle fractures may be allowed to heal in an imperfect but acceptable alignment (“bayonet” apposition) without resulting functional loss. Similarly, mild angulation of a humerus fracture does not impair use of the upper extremity.

Source: Medical Disability Advisor



Prognosis

Treatment of malunion by ORIF usually has a good outcome. Osteotomy can reduce deformity and relieve functional impairment, but this places the bone at risk of fracture. Minor degrees of malunion are common and may not have a significant effect on function or appearance.

Bone grafting usually is a successful treatment for nonunion, especially in the long bones of the body. Electrical and electromagnetic bone growth stimulators continue to progress and are especially advantageous in management of infected nonunions and in situations where surgery is not advisable. Low-frequency ultrasound therapy may decrease fracture-healing time in lower extremity nonunions by as much as two months (Patel). Bone marrow injection into the site of nonunion may resolve the nonunion without need for further surgery (Patel).

Source: Medical Disability Advisor



Complications

A malunion can result in a functional impairment with limited mobility. Any malunion can put increased stress on other joints causing pain and / or accelerated wear. Major degrees of malunion can cause impairment in function and significant deformity and can lead to degenerative arthritis. Malunion in a finger can interfere with the use of other fingers. Nerve damage can occur, especially with an elbow fracture. A malunion in a leg can result in an abnormal gait.

A nonunion may be painless, but the fracture will be unstable and the bone less strong. Nonunions in a lower extremity may result in reliance upon assistive devices (e.g., crutches, wheelchairs) for mobility.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

The restrictions and accommodations are determined by the specific fracture, the severity of the malunion or nonunion, and job requirements. See specific fracture topics for more information. If surgical correction is necessary, work duties may need to be modified temporarily to avoid use of the affected limb. 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 a malunion or a nonunion?
  • Does individual report pain, instability, or deformity at the site of a previous fracture?
  • Has malunion or nonunion been confirmed by x-rays, bone scan, or other imaging studies?
  • Have conditions with similar symptoms been ruled out?

Regarding treatment:

  • Was adequate time allowed for bone to heal?
  • Did individual require functional bracing of the limb?
  • Did individual require ORIF?
  • Was bone graft done? Bone marrow injection?
  • Did individual use low-intensity ultrasound? Electrical bone stimulation?
  • Was rehabilitation program prescribed? Was individual compliant?

Regarding prognosis:

  • Does individual continue to have risk factors for delay of fracture healing (e.g., corticosteroid use, smoking, malnutrition)?
  • What are individual's functional limitations as a result of the malunion/nonunion?
  • Is individual active in physical therapy or rehabilitation program?
  • Does individual have any comorbid conditions that could influence length of disability (e.g., diabetes, bone cancer, osteoporosis)?
  • Has individual experienced any complications, such as nerve damage, abnormal gait, or degenerative arthritis?
  • Is individual's employer able to accommodate necessary restrictions and work modifications?

Source: Medical Disability Advisor



References

Cited

Boles, C. A. "Wrist, Scaphoid Fractures, and Complications." eMedicine. Eds. Bernard D. Coombs, et al. 16 Nov. 2007. Medscape. 29 Jun. 2009 <http://emedicine.medscape.com/article/397230-overview>.

Cleveland, Kevin B. "Delayed Union and Nonunion of Fractures." Campbell's Operative Orthopaedics. Eds. S. Terry Canale and James H. Beaty. 11th ed. Philadelphia: Mosby Elsevier, 2008.

Court-Brown, C. M., and M. M. McQueen. "Nonunions of the Proximal Humerus: Their Prevalence and Functional Outcome." Journal of Trauma, Injury, Infection and Critical Care 64 6 (2008): 1517-1521.

Milner, S. A., et al. "Long-term Outcome after Tibial Shaft Fracture: Is Malunion Important?" Journal of Bone and Joint Surgery 84 (2002): 971-980.

Mundi, R., et al. "Low-intensity Pulsed Ultrasound: Fracture Healing." Indian Journal of Orthopaedics 43 (3009): 132-140.

Patel, Minoo, James J. McCarthy, and John Herzenberg. "Tibial Nonunions." eMedicine. Eds. Charles T. Mehlman, et al. 22 Apr. 2009. Medscape. 29 Jun. 2009 <http://emedicine.medscape.com/article/1252306-overview>.

Robinson, C. M., et al. "Estimating the Risk of Nonunion Following Nonoperative Treatment of a Clavicular Fracture." Journal of Bone and Joint Surgery 89 (2004): 1359-1365.

Stannard, J. P., A. H. Schmidt, and P. J. Kregor, eds. "Chapter 22: Outcomes. Intracapsular Hip Fractures." Surgical Treatment of Orthopaedic Trauma. New York: Thieme Medical Publishers, 2007.

Van Oosterom, F. J. T., et al. "Treatment of Phalangeal Fractures in Severely Injured Hands." The Journal of Hand Surgery: Journal of the British Society for Surgery of the Hand 26 2 (2001): 108-111.

Source: Medical Disability Advisor






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