Genu Valgum: A Closer Look at Knock Knees
Knock knees, known medically as genu valgum, is a condition in which the knees bend inward, causing them to touch or "knock" against each other when a person stands with their ankles apart. While many associate this with childhood development—a phase most children outgrow by age seven or eight—it can also develop or worsen in adulthood. In adults, this is not a benign developmental stage but rather a pathological condition that can cause pain, gait issues, and progressive joint damage over time.
The Role of Aging in Knee Alignment
As we age, our joints undergo several natural changes. The cartilage that cushions our bones thins, bones lose density, and connective tissues become less flexible. While these changes don't automatically cause knock knees, they make the knee joint more susceptible to conditions that can lead to misalignment. The balance between catabolic and anabolic activity in joint tissues can be disrupted, increasing the risk of damage. For individuals predisposed to joint problems, the accumulation of these age-related factors can trigger a valgus deformity that was not present in youth.
Leading Causes of Adult-Onset Knock Knees
For adults, knock knees are most often the result of an underlying condition or past trauma. These causes place imbalanced stress on the knee, leading to gradual or rapid deformation. Some of the most common reasons include:
Osteoarthritis and Rheumatoid Arthritis
Arthritis is a primary driver of knock knees in seniors. Both osteoarthritis (OA) and rheumatoid arthritis (RA) can cause a progressive degradation of the joint. With OA, or "wear-and-tear" arthritis, the cartilage wears away, leading to bone-on-bone contact. This uneven wearing, especially on the outer (lateral) side of the knee, can cause the joint to collapse and twist inward, worsening the valgus deformity over time.
Prior Trauma or Injury
Past injuries to the leg or knee can lead to a gradual misalignment. A fracture that heals improperly (a malunion), damage to the growth plate during childhood, or trauma to the meniscus can all affect the mechanical axis of the leg. Over many years, this pre-existing condition can worsen, eventually leading to a noticeable knock-kneed appearance.
Weight Gain and Obesity
Carrying excess body weight puts additional strain on the knee joints, accelerating the breakdown of cartilage and other tissues. This increased load can exacerbate any pre-existing joint instability or alignment issues, causing the knees to move inward over time. Weight management is therefore a crucial component of prevention and treatment.
Muscle Weakness and Connective Tissue Disorders
Long-term muscle weakness, particularly in the hips, can contribute to knee misalignment. Weak gluteus maximus muscles can cause the knee to collapse inward during walking. Less commonly, connective tissue disorders like Ehlers-Danlos syndrome can cause joint hypermobility and instability, contributing to knock knees.
Diagnosis and Symptoms in Older Adults
For an older adult, knock knees are typically diagnosed through a physical examination and imaging studies like a standing alignment X-ray. This provides a clear picture of the mechanical axis of the leg and the degree of deformity. Symptoms often accompany the condition and can include:
- Pain in the knees, hips, or ankles
- Instability or a feeling that the knee may "give way"
- A limp or an altered walking gait (sometimes described as a "scissor walk")
- Stiffness or soreness in the joints
- Difficulty walking or running
Treatment Options for Adult Genu Valgum
Treatment for knock knees in older adults depends on the severity and underlying cause. Unlike in children, where the issue often self-corrects, adult cases tend to worsen without intervention and require a more active management approach.
Non-Surgical Treatments
- Weight management: Reducing excess body weight is one of the most impactful ways to decrease stress on the knees and slow the progression of degeneration.
- Physical therapy: Targeted exercises can help strengthen the muscles that support the knee and improve gait. This can include strengthening the quadriceps and abductor muscles.
- Orthotics and bracing: Custom shoe inserts (orthotics) can help correct foot alignment and posture. An unloader knee brace can reduce pressure on the damaged side of the joint.
- Medication: Over-the-counter pain relievers or anti-inflammatory drugs can help manage pain and inflammation associated with arthritis.
Surgical Treatments
- Osteotomy: For significant deformities not yet advanced to end-stage arthritis, an osteotomy may be performed. This surgery involves cutting and realigning the thigh bone (femoral osteotomy) or shin bone (high tibial osteotomy) to restore proper alignment and redistribute weight more evenly across the knee.
- Total Knee Replacement: In older patients with severe arthritis and significant deformity, a total knee replacement may be the most suitable option. This procedure replaces the damaged joint surfaces and offers an excellent option for correcting the deformity and relieving arthritic pain.
Physiological vs. Pathological Knee Changes: A Comparison
| Feature | Normal Age-Related Knee Changes | Pathological Genu Valgum (Knock Knees) |
|---|---|---|
| Symptom Onset | Gradual, often minor stiffness or reduced flexibility | Often sudden, progressive pain, instability, and gait changes |
| Underlying Cause | Natural wear and tear of cartilage, thinning synovial fluid, connective tissue stiffening | Secondary to arthritis, trauma, or other medical conditions |
| Effect on Joint | General reduction in cartilage thickness and flexibility | Uneven cartilage wear, particularly on the outer compartment, leading to bone deformity |
| Progression | Slow and steady decline in flexibility and range of motion | Can worsen rapidly, especially with advanced arthritis |
| Gait Changes | Possible subtle changes due to stiffness | Distinctive inward angling of knees and possible limp |
Conclusion
Yes, it is possible to become knock-kneed as you get older, though this is not a standard part of the aging process. It is typically the result of underlying conditions like osteoarthritis, past trauma, or obesity that are exacerbated by age-related joint changes. Addressing these contributing factors early is key to managing symptoms and slowing progression. If you notice a change in your knee alignment, seeking evaluation from an orthopedic specialist can help determine the best course of action, from physical therapy to surgical correction. For more in-depth information, you can read more about joint health at Physiopedia.
