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.

Bone Graft


Related Terms

  • Bone Transplant
  • Donor bone

Specialists

  • Neurosurgeon
  • Orthopedic (Orthopaedic) Surgeon
  • Otolaryngologist
  • Plastic Surgeon

Comorbid Conditions

Factors Influencing Duration

Factors related to length of disability include the type of graft (autograft vs. allograft), the site of the graft (weight-bearing versus non-weight-bearing), the amount of blood loss, the extent of the graft, and subsequent infection.

Medical Codes

ICD-9-CM:
02.04 - Cranioplasty; Bone Graft to Skull; Pericranial Graft (Autogenous) (Heterogenous)
76.39 - Partial Ostectomy of Other Facial Bone; Hemimaxillectomy (with Bone Graft or Prosthesis)
76.91 - Bone Graft to Facial Bone; Autogenous Graft to Facial Bone; Bone Bank Graft to Facial Bone; Heterogenous Graft to Facial Bone

Overview

A bone graft is the placement of a piece of bone onto or into a damaged or defective bone to help its repair or to replace a missing portion. Eventually most of the graft is reabsorbed and is then replaced by new bone; in the meantime, the graft provides a scaffold on which new bone will grow. The mechanisms operative in successful grafts are osteoconduction (providing a scaffold for the reparative growth of natural bone), osteoinduction (induction of undifferentiated cells to become active osteoblasts), osteopromotion (enhancement of osteoinduction without having osteoinductive properties), and osteogenesis (contribution to new bone growth and bone remodeling by the living bone cells in the graft material, occurring only in autografts).

Some bone grafts are needed for structural support. A hard bone (cortical bone), such as the tibia or a rib, is used for this purpose. This type of bone is slow to incorporate. It will last a long time, even years, before it is replaced by new bone growth.

Some bone grafts are needed for osteogenesis. This type of graft requires a spongy bone (cancellous bone), which triggers new bone growth more quickly and is often obtained from the iliac crest. While it possesses no structural integrity, this bone material obtains growth either by supplying living cells or by chemically triggering the growth of new cells by the host.

Sometimes bone is needed that already contains vessels (vascularized bone graft). This type of graft is needed in areas where blood supply is low or absent and where large defects must be repaired. Portions of the fibula (fibularis graft) are often used for vascularized bone grafts. These grafts remain and are replaced by new bone growth only at the end where it touches the recipient's bone. In the hand, the most common indications for vascularized bone grafts are scaphoid nonunion, lunatomalacia, and osteonecrosis of the scaphoid.

Bone for the graft may be supplied from another site on the individual (autograft or autogeneic graft) or from another person or a cadaver (allograft or allogeneic graft). Bone grafts from other species (xenograft) have been attempted but are not recommended due to poor outcomes.

Autograft is the best way in which to transplant living bone cells that will grow into new bone. The bones most commonly used for autografts are the tibia (used for cortical graft), the fibula (used for cancellous or whole bone transplant), and the iliac crest (used for cancellous graft).

An allograft is the best choice when more bone is needed than can be physically or safely removed from the patient. Allografts typically provide more structural support and less osteogenesis. They do, however, trigger the growth of new bone in the host, even though they do not provide living cells. Sometimes, for a problem that requires both structural support and osteogenesis, a graft will contain both autogeneic and allogeneic material.

Ceramic materials can be used as cancellous bone substitutes. Hydroxyapatite and tricalcium phosphate create scaffolding on which new bone can grow. Their structure allows easy access for blood vessels and bone-forming cells (osteogenic cells). They are used in areas where bulk, rather than strength, is needed. A mixture of hydroxyapatite/tricalcium phosphate, ceramic beads, fibrillar collagen, and added autogenous bone marrow elements has also been used as a substitute for cancellous grafts.

Biochemical substances such as bone morphogenic protein (BMP), demineralized bone matrix (BMG), fibroblast growth factor (FGF), and platelet-derived growth factor (PDGF) show promise in encouraging new bone growth (Laurencin).

Source: Medical Disability Advisor



Reason for Procedure

Bone grafts are used to promote healing (union) of fresh fractures, and fill in areas left vacant after the removal of cysts, tumors, or bone that is necrotic due to, for example, trauma or infection. They are also used to fuse joints (arthrodesis) such as in the spine (spinal fusion), as well as to limit joint motion by placing a bone block (arthrorisis).

Source: Medical Disability Advisor



How Procedure is Performed

Bone grafts are performed in a hospital under general or regional anesthesia. In an autograft, the bone is removed and implanted during the same surgery. In an allograft, the surgery includes only placing the bone graft.

The damaged portions of the bone are cut away, and the graft is shaped to fit. The graft is either placed on top of the bone surface (overlay graft), as in a fracture repair, or inserted into an empty cavity within the bone (inlay graft), such as after a tumor or cyst has been removed.

Multiple cancellous chip grafts make use of pieces of cancellous bone. These pieces are packed into crevasses and holes created by the removal of a cyst or tumor. They are also packed around an artificial joint to stabilize it. A portion of an individual's own bone marrow (autologous bone marrow) is sometimes added to grafts to increase the potential of growing new bone.

Hemicylindrical graft is an extensive surgical procedure in which a large hemicylindrical cortical graft is removed from the affected bone. This graft, plus additional cancellous bone from the iliac, is placed across the defect. This procedure is used to prevent amputation following the removal of certain bone tumors.

Whole bone transplant, using primarily the fibula, replaces large pieces of bone in the arms that have typically been damaged by removal of a large tumor or where other major bone loss has occurred.

Removing and implanting a vascularized graft is a type of microvascular surgery. It is more complicated than a nonvascularized graft. Vascularized bone grafts may be either free or pedicled grafts.

Bone used in an allograft is obtained from a bone bank and is usually processed. If used fresh, it would, like other transplanted tissue, soon trigger an inflammatory reaction. Processing (sterilization, followed by freezing or freeze-drying) reduces the graft's ability to trigger this reaction. Like any tissue donor, donors of bone grafts are screened for a number of conditions that would be hazardous to the recipient: bacterial, fungal, and viral (HIV, hepatitis B, and hepatitis C) infection; malignancy; collagen vascular disease; metabolic bone disease; and the presence of toxins.

Source: Medical Disability Advisor



Prognosis

The individual may have difficulty bearing weight for some time following the surgery. Although not all grafts generate the new bone growth or stability hoped for, both autogeneic and allogeneic bone grafts are typically successful. Dynamic exercise may be unsuitable for up to 3 months (Vorvick). Use of nicotine may delay incorporation of a graft and may delay wound/injury healing.

Source: Medical Disability Advisor



Rehabilitation

Individuals who undergo bone graft will most likely require physical therapy. The type and duration is related to the type and site of surgery (for example, hip replacement) and the site of autologous graft removal, if applicable. Individuals will learn range of motion and strengthening exercises for the muscles that surround the graft site and graft removal site (if applicable). Finally, individuals will learn mobility techniques for walking and transferring if the graft site is located on the low back or leg.

Source: Medical Disability Advisor



Complications

In an autograft, the individual faces complications of both bone removal and bone placement. The surgery is longer and more complicated, with a greater risk of sufficient blood loss to require transfusion. The normal limb or iliac crest from which the graft is taken is at risk of damage and instability. Adjacent nerves and muscles may also sustain damage. Both the donor and the recipient site take longer to heal. The donor site is at risk of injury, such as fracture. After removal of a portion of the iliac crest, there is risk of hernia, nerve and/or arterial injury, and cosmetic deformity. Donor sites may be reported as painful based on similar criteria.

Despite screening, in an allograft there is the possibility of contracting a bloodborne disease from the donated tissue. Also, despite processing, the risk of an inflammatory reaction remains, albeit slight. No antirejection drugs are given in an allograft.

As in all surgeries, postsurgical infections are a risk in both allograft and autograft procedures. Anesthesia always carries the risks of breathing problems and reaction to the anesthetics used.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

The surgical site must be protected until the physician deems it strong. The site from which an autograft was removed may be protected by work restrictions for up to 12 months from injury such as fracture. The type and site of surgery will dictate specific restrictions.

Accommodations: Physical limitations as a result of the bone graft procedure may result in the need for accommodations. Each individual is unique as is each employer. By working together, they can often return an individual to modified work at an early date.

Source: Medical Disability Advisor



Maximum Medical Improvement

Depending on size and location, MMI can vary from 45 days to 180 days.

Source: Medical Disability Advisor



References

Cited

Laurencin, Cato T., et al. "Bone Graft Substitute Materials." eMedicine. Eds. Jonathan Black, et al. 16 Feb. 2012. Medscape. 10 Oct. 2013 <http://emedicine.com/orthoped/topic611.htm>.

Vorvick, Linda J. "Bone Graft." MedlinePlus. 11 Aug. 2012. National Library of Medicine. 2 Oct. 2013 <http://www.nlm.nih.gov/medlineplus/ency/article/002963.htm>.

Source: Medical Disability Advisor






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