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Chapter 6: Musculoskeletal Secondary Conditions
Chapter 6
Musculoskeletal Secondary Conditions
Musculoskeletal conditions are among the most common service-connected disabilities for veterans, and they frequently lead to a cascade of secondary conditions. The body’s musculoskeletal system functions as an interconnected chain, where dysfunction in one area inevitably affects other areas.
Key Concept
Musculoskeletal secondary conditions typically develop through these pathways:
- Biomechanical compensation (altered movement patterns)
- Referred pain and nerve impingement
- Muscle imbalances and atrophy
- Joint instability and accelerated degeneration
- Medication side effects from pain management
This chapter explores the most common musculoskeletal secondary conditions that develop from service-connected injuries and provides the medical evidence and strategies needed to successfully claim them.
The Biomechanical Chain Reaction
The human body functions as an integrated kinetic chain where movement and stress in one area influence other areas. Understanding this biomechanical chain reaction is crucial for identifying potential secondary conditions.
Compensation Patterns
When one joint or muscle is injured, the body naturally shifts load to other structures to avoid pain. Over time, these compensation patterns lead to excessive stress on secondary areas, resulting in new injuries or accelerated degeneration.
Example: A service-connected knee injury causes a veteran to shift weight to the opposite leg, resulting in hip pain and eventual osteoarthritis in the opposite hip.
Kinetic Chain Relationships
The musculoskeletal system has predictable relationships between its components. Injuries to certain areas commonly lead to specific secondary conditions in connected structures.
Example: Service-connected lumbar spine injuries frequently lead to sacroiliac joint dysfunction, as the altered spinal mechanics place abnormal stress on the sacroiliac joint.
(Click to enlarge)
As illustrated in the diagram, injuries to primary joints (highlighted in red) create a predictable pattern of stress and strain on connected structures, often leading to secondary conditions in these areas over time.
Lower Extremity Secondary Conditions
Service-connected injuries to the lower extremities—feet, ankles, knees, and hips—frequently lead to secondary conditions in other joints due to the body’s connected weight-bearing structure.
| Primary Service-Connected Condition | Common Secondary Conditions | Medical Mechanism |
|---|---|---|
| Knee Injury (e.g., meniscus tear, ACL injury, arthritis) |
|
Altered gait pattern shifts weight distribution; compensation causes abnormal stress on other joints; muscle imbalances develop from favoring the injured side |
| Ankle Injury (e.g., fracture, chronic instability, arthritis) |
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Restricted ankle motion forces compensatory movement in other joints; altered foot mechanics affect entire kinetic chain; reduced shock absorption increases stress on proximal joints |
| Hip Condition (e.g., arthritis, labral tear, impingement) |
|
Hip joint restrictions alter pelvic positioning; compensation creates abnormal spine mechanics; altered weight-bearing patterns increase stress on contralateral hip and ipsilateral knee |
| Foot Condition (e.g., plantar fasciitis, flat feet, stress fracture) |
|
Abnormal foot mechanics alter weight distribution through entire leg; improper shock absorption; muscle imbalances from altered movement patterns |
Case Example: Knee to Back Secondary Connection
A Marine Corps veteran with a service-connected right knee injury from a parachute jump developed chronic low back pain 8 years after service. His orthopedic specialist documented how his knee injury caused an antalgic gait (limping to avoid pain), which resulted in pelvic tilt and lumbar spine strain. Over time, this abnormal movement pattern led to accelerated disc degeneration in his lumbar spine. MRI imaging confirmed degenerative disc disease, and the specialist provided a nexus opinion stating the back condition was “at least as likely as not” caused by the altered biomechanics resulting from the service-connected knee condition. The VA granted service connection for the lumbar spine condition as secondary to the knee injury.
Upper Extremity Secondary Conditions
Service-connected injuries to the upper extremities can lead to a cascade of secondary conditions through altered movement patterns and compensatory mechanisms.
Shoulder Injuries
Primary Conditions: Rotator cuff tears, labral injuries, glenohumeral arthritis, impingement syndrome
Secondary Conditions:
- Cervical spine strain/degeneration
- Opposite shoulder overuse injuries
- Thoracic outlet syndrome
- Elbow tendinitis
Medical Mechanism: Shoulder injuries alter scapulothoracic mechanics, affecting neck posture and muscle balance. Compensation with the opposite arm leads to overuse injuries. Restricted shoulder motion places additional stress on the elbow joint.
Elbow and Wrist Injuries
Primary Conditions: Lateral/medial epicondylitis, cubital tunnel syndrome, wrist fractures, carpal tunnel syndrome
Secondary Conditions:
- Shoulder impingement or tendinitis
- Cervical radiculopathy
- Opposite limb overuse conditions
- Hand and finger joint degeneration
Medical Mechanism: Elbow and wrist injuries cause altered movement patterns that affect shoulder mechanics. Compensation leads to neck strain. Restricted motion in one joint transfers stress to adjacent joints.
Evidence Tip: Objective Documentation
For upper extremity secondary claims, the following objective evidence can significantly strengthen your case:
- Posture and movement assessments documenting altered mechanics
- Comparative imaging showing greater degeneration on the affected side or compensating side
- Electromyography (EMG) studies showing altered muscle activation patterns
- Range of motion measurements documenting limitations and their effects on adjacent joints
Spine-Related Secondary Conditions
The spine serves as the central support structure for the body, and service-connected spine conditions frequently lead to secondary conditions in connected structures and systems.
| Spine Region | Primary Condition | Common Secondary Conditions |
|---|---|---|
| Cervical Spine (Neck) |
|
|
| Thoracic Spine (Mid-back) |
|
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| Lumbar Spine (Low back) |
|
|
Radiculopathy Claims
Radiculopathy—nerve impingement causing pain, numbness, or weakness radiating into the extremities—is one of the most common and successfully claimed spine-related secondary conditions.
When claiming radiculopathy secondary to a spine condition, ensure your evidence includes:
- EMG/nerve conduction studies documenting the specific nerves affected
- MRI evidence showing disc herniation or foraminal narrowing affecting specific nerve roots
- Clinical documentation of sensory and motor deficits in the affected extremities
- A medical opinion connecting the radiculopathy to the service-connected spine condition
Contralateral Joint Conditions
One of the most significant categories of musculoskeletal secondary conditions involves injuries to corresponding joints on the opposite side of the body (contralateral joints). These conditions develop as veterans shift weight and stress to the uninjured side to compensate for pain and limitations on the service-connected side.
Medical Basis for Contralateral Claims
Medical research has established several mechanisms through which service-connected conditions lead to contralateral joint issues:
- Overload phenomenon: The uninjured limb bears more weight and stress, leading to accelerated wear and tear.
- Altered biomechanics: Changes in gait, posture, and movement patterns place abnormal stress on the contralateral limb.
- Muscle imbalances: Compensatory movement patterns create muscle imbalances that affect both sides of the body.
- Cross-education effect: Neurological changes affect muscle activation and coordination on both sides of the body.
Contralateral joint conditions can involve any paired structures, but the most common include opposite knee, hip, ankle, shoulder, and wrist conditions. The VA has recognized many such connections in precedential decisions, making these conditions viable secondary claims when properly documented.
Case Example: Right Knee Secondary to Left Knee
An Army veteran with a service-connected left knee condition (post-traumatic arthritis from an injury during training) developed right knee pain and degeneration approximately 10 years after service. His orthopedic specialist documented that the veteran’s altered gait from the left knee condition caused him to place increased weight and stress on his right knee for many years. This overload led to premature degeneration of the right knee joint. X-rays showed bilateral knee arthritis, but more advanced in the service-connected left knee. The specialist provided a medical opinion stating: “The development of right knee osteoarthritis is at least as likely as not the result of altered biomechanics and increased mechanical loading secondary to the veteran’s service-connected left knee condition.” The VA granted service connection for the right knee condition as secondary to the left knee disability.
Medication-Induced Musculoskeletal Conditions
Medications prescribed for service-connected musculoskeletal conditions can themselves cause secondary musculoskeletal issues, particularly with long-term use.
| Medication Class | Commonly Prescribed For | Potential Secondary Conditions |
|---|---|---|
| Corticosteroids (prednisone, cortisone injections) |
|
|
| NSAIDs (ibuprofen, naproxen, meloxicam) |
|
|
| Statins (often prescribed for veterans with limited mobility) |
|
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| Muscle Relaxants (cyclobenzaprine, baclofen) |
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|
Evidence Tip: Medication Documentation
When claiming a musculoskeletal condition secondary to medication effects, ensure your evidence includes:
- Complete VA pharmacy records documenting medication prescriptions, dosages, and duration
- Medical literature (references or excerpts) documenting the known association between the medication and the secondary condition
- Medical opinion addressing whether alternative medications were available or considered
- Temporal relationship documentation showing the onset of the secondary condition after starting the medication
Strategies for Musculoskeletal Secondary Claims
Successfully claiming secondary musculoskeletal conditions requires strategic documentation and evidence development. The following approaches can significantly strengthen your claim:
Document Biomechanical Changes
Have your healthcare provider document specific biomechanical changes caused by your service-connected condition. This might include altered gait patterns, postural changes, or compensation mechanisms. Video documentation can be particularly compelling for claims based on altered movement patterns.
Obtain Comparative Imaging
When claiming a contralateral joint condition, obtain imaging studies of both the service-connected joint and the secondary joint. Comparative analysis can demonstrate the relationship between the conditions and the progression of degeneration, especially when the non-service-connected side shows less age-appropriate degeneration than would be expected.
Track Progression Over Time
Document the progression of your symptoms and limitations over time, establishing a clear timeline showing how the secondary condition developed or worsened following the service-connected condition. Medical records showing consistent complaints about the secondary area strengthen the connection.
Secure a Detailed Medical Opinion
Obtain a comprehensive medical opinion from a specialist (orthopedist, physiatrist, rheumatologist) that specifically addresses the biomechanical relationship between your conditions. The opinion should reference medical literature supporting the connection and use the “at least as likely as not” standard required by the VA.
Sample Medical Opinion Language
Here’s an example of effective language for a medical opinion supporting a musculoskeletal secondary claim:
“Based on my examination of [Veteran’s Name], review of their medical records, and my professional expertise as an [orthopedic surgeon/physiatrist/etc.], it is my opinion that the veteran’s [secondary condition] is at least as likely as not (50% or greater probability) caused by their service-connected [primary condition]. The veteran’s [primary condition] has resulted in [specific biomechanical changes, e.g., ‘an antalgic gait with increased weight-bearing on the right lower extremity’], which has placed abnormal stress on the [secondary condition location]. This causal relationship is supported by medical literature, including [specific study or reference if available], which demonstrates that [brief summary of relevant medical principle]. The timing of the veteran’s symptoms, progression of imaging findings, and absence of other causative factors further support this connection.”
Chapter Summary
- Musculoskeletal conditions are among the most common service-connected disabilities, and they frequently lead to secondary conditions through biomechanical chain reactions.
- Lower extremity service-connected conditions often lead to secondary conditions in other weight-bearing joints, the spine, and contralateral limbs due to altered gait and compensation patterns.
- Upper extremity injuries can cause secondary conditions through altered movement patterns, muscular imbalances, and compensatory overuse of other structures.
- Spine conditions frequently lead to radiculopathy, sacroiliac joint dysfunction, and other secondary conditions due to altered biomechanics and nerve involvement.
- Contralateral joint conditions develop as veterans shift weight and stress to the uninjured side to compensate for pain and limitations on the service-connected side.
- Medications prescribed for service-connected musculoskeletal conditions can themselves cause secondary musculoskeletal issues, particularly with long-term use.
- Successful claims for musculoskeletal secondary conditions require documentation of biomechanical changes, comparative imaging, progression over time, and detailed medical opinions addressing the specific connection between conditions.