Osteoarthritis - Disordered joint mechanics Factor
RMA Definition
Disordered joint mechanics means "maldistribution of loading forces on that joint resulting from:
- a rotation or angulation deformity of the long bones of the affected limb; or
- a rotation or angulation deformity of the hip, knee, or ankle joint of the affected limb."
Important information
The most important part of this definition is the requirement for maldistribution of loading forces. This does not mean simply an increase in loading forces. It means the forces through the affected joint (ie the joint which is the subject of the claim) must be distributed in an abnormal way. Thus the common argument that a bad knee/ankle/hip on one side caused a limp, leading to added strain on a knee/ankle/hip on the other side is not valid where there is simply an increase in loading forces on the other side – there must be maldistribution of loading forces on that side.
Note: There is now a separate factor for leg amputation or asymmetric gait. You should also consider this factor if the person is contending that the disordered joint mechanics is due to either of these reasons.
In general, there should be medical evidence of disordered joint mechanics.
The following are examples of circumstances which may meet the SOP definition:
- a fracture of the tibia or fibula that has healed in a twisted or bent position (a rotation or angulation deformity) may cause maldistribution of loading forces in the knee or ankle of the same limb;
- a significant ankle or foot deformity can cause disordered action and loading forces in the knee or even the hip on the same side;
- maldistribution of forces through the hip joint could arise from pelvic tilting resulting from conditions such as scoliosis (lateral curvature of the spine), kyphosis (abnormally increased convexity in the curvature of the thoracic spine), spondylolisthesis (a condition causing forward displacement of a lower lumbar vertebra), spina bifida (a defect in the development of the vertebral column), Paget's disease of the spine ( also called osteitis deformans - a disorder of bone structure).
NOTE:
In general, pathology outside the affected limb ( ie outside the limb which is the subject of the claim), is not going to cause maldistribution of loading forces through the knee or ankle joint in that limb. If a person can weight bear on the foot of the affected limb in a relatively normal fashion with the foot pointing forward and vertically in line with the knee and hip, then, in general, it can be said that pathology outside that limb is not resulting in the necessary maldistribution of loading forces in the knee or ankle joint.
Last reviewed for CCPS 10 June 2012.
Investigative Documents
| Type | Title | PDF Format | Word Format |
|---|---|---|---|
| Medical Report | Disordered Joint Mechanics |
Preliminary questions [8631]
31383 there is some evidence that disordered joint mechanics may be a factor in the development or worsening of the condition under consideration.
31384 the veteran has had disordered joint mechanics affecting side and site of the body at some time.
31385 the veteran had disordered joint mechanics affecting side and site of the body as a consequence of an illness or injury which is identifiable.
25521 the veteran has established the causal connection between the disordered joint mechanics affecting side and site of the body and VEA service for the condition under consideration.
31388 the veteran has established the causal connection between the disordered joint mechanics affecting side and site of the body and VEA service for the clinical onset of the condition under consideration.
31390 the veteran has established the causal connection between the disordered joint mechanics affecting side and site of the body and operational service for the clinical onset of the condition under consideration.
or
31392 the veteran has established the causal connection between the disordered joint mechanics affecting side and site of the body and eligible service for the clinical onset of the condition under consideration.
or
7334 the clinical onset of the condition under consideration occurred after the end of the veteran's last period of VEA service.
7335 the condition under consideration permanently worsened.
31389 the veteran has established the causal connection between the disordered joint mechanics affecting side and site of the body and VEA service for the clinical worsening of the condition under consideration.
31391 the veteran has established the causal connection between the disordered joint mechanics affecting side and site of the body and operational service for the clinical worsening of the condition under consideration.
or
31393 the veteran has established the causal connection between the disordered joint mechanics affecting side and site of the body and eligible service for the clinical worsening of the condition under consideration.
Clinical onset and operational service [31390]
41605 the veteran had the disordered joint mechanics affecting side and site of the body, as a consequence of the identified illness or injury, for at least three years before the clinical onset of the condition under consideration.
31395 the identified illness or injury, which caused the disordered joint mechanics affecting side and site of the body, is causally related to operational service.
Clinical onset and eligible service [31392]
41606 the veteran had the disordered joint mechanics affecting side and site of the body, as a consequence of the identified illness or injury, for at least five years before the clinical onset of the condition under consideration.
31396 the identified illness or injury, which caused the disordered joint mechanics affecting side and site of the body, is causally related to eligible service.
Clinical worsening and operational service [31391]
41603 the veteran had the disordered joint mechanics affecting side and site of the body, as a consequence of the identified illness or injury, for at least three years before the clinical worsening of the condition under consideration.
31395 the identified illness or injury, which caused the disordered joint mechanics affecting side and site of the body, is causally related to operational service.
31397 the clinical onset of the condition under consideration occurred prior to that part of operational service to which the identified illness or injury, which caused the disordered joint mechanics affecting side and site of the body, is causally related.
Clinical worsening and eligible service [31393]
41604 the veteran had the disordered joint mechanics affecting side and site of the body, as a consequence of the identified illness or injury, for at least five years before the clinical worsening of the condition under consideration.
31396 the identified illness or injury, which caused the disordered joint mechanics affecting side and site of the body, is causally related to eligible service.
31398 the clinical onset of the condition under consideration occurred prior to that part of eligible service to which the identified illness or injury, which caused the disordered joint mechanics affecting side and site of the body, is causally related.