Genu valgum, commonly known as knock knees, is a condition where the knees angle inward, touching or nearly touching, while the ankles remain separated when a person stands with their legs straight. While this alignment is a normal part of development in many young children, its persistence or late onset in adulthood presents a significant challenge. For adults, this misalignment is not merely a cosmetic concern; it is a biomechanical issue that can lead to chronic pain and progressive joint degradation over time. The goal of intervention is to restore a healthier mechanical axis to the leg, exploring a spectrum of options from non-invasive therapies to surgical correction.
Understanding Adult Genu Valgum
Genu valgum in adults often results from a condition that persisted from childhood, but it can also develop later in life. Acquired causes include trauma or injury to the knee, metabolic bone diseases like rickets, or secondary effects of advanced arthritis. Obesity is also a contributing factor, as excess weight places a greater load on the knee joints, potentially accelerating the inward collapse.
The biomechanical consequence of this inward angulation is a shift in the distribution of weight across the knee joint. The mechanical axis of the leg, which should pass through the center of the knee, is displaced toward the outside. This uneven loading increases the likelihood of developing lateral compartment osteoarthritis, which is often accompanied by pain, instability, and an altered walking pattern.
Non-Surgical Correction Strategies
For adults with mild to moderate knock-knee alignment or those experiencing early symptoms, initial management focuses on non-invasive strategies to manage pain and improve joint mechanics. A personalized physical therapy program is a frequent starting point for non-surgical treatment.
Physical Therapy and Exercise
Physical therapy is designed to address muscle imbalances that contribute to poor knee alignment and stability. A primary focus is strengthening the muscles that control the hip and thigh, particularly the hip abductors, such as the gluteus medius. Strengthening these muscles helps to better stabilize the pelvis and reduce the inward rotation and collapse of the knee during walking and standing.
Specific exercises often include side-lying leg raises, clamshells, and various squatting techniques that emphasize proper form and alignment. Strengthening the quadriceps and core muscles provides additional support to the knee joint, improving overall stability and function.
Orthotics and Bracing
Custom-made foot orthotics are often prescribed to address underlying issues in foot mechanics that can worsen knee alignment. Many individuals with genu valgum also exhibit overpronation, where the arch of the foot collapses inward. The orthotics work to support the arch and correct the foot’s posture, which in turn reduces rotational stress that travels up the leg to the knee.
For knee pain associated with lateral compartment wear, an unloader knee brace may be beneficial. This specialized brace is designed to apply pressure that subtly shifts the weight-bearing load away from the damaged outer compartment of the knee toward the healthier inner compartment. This shift in loading can provide pain relief and potentially slow the rate of cartilage deterioration.
Lifestyle Modifications
Weight management is a practical strategy for reducing the overall mechanical stress placed on the knee joints. Excess body weight exacerbates the compressive forces on the stressed lateral compartment of the knee, accelerating the progression of symptoms. Modifying high-impact activities, such as running or jumping, in favor of lower-impact exercises like swimming or cycling, can also help preserve joint health by reducing repetitive impact forces.
When Surgery Becomes Necessary
When non-surgical treatments fail to manage pain, or if the angular deformity is severe, surgical correction becomes a consideration. Surgery is typically reserved for cases involving significant pain, advanced arthritis, or a pronounced angular misalignment. The two main surgical options are a bone-realigning procedure or a joint replacement.
Distal Femoral Osteotomy
For correcting adult genu valgum, the preferred realignment procedure is often a Distal Femoral Osteotomy (DFO), which targets the thigh bone. This procedure involves cutting the femur near the knee joint and then reshaping the bone to reposition the mechanical axis of the leg. The goal is to shift the weight-bearing load away from the damaged outer compartment of the knee toward the healthier inner compartment.
The surgeon either removes a wedge of bone or opens a wedge, fixing the new alignment with a plate and screws. This structural change aims to preserve the patient’s own knee joint and is generally recommended for younger, active individuals with localized arthritis. Recovery is lengthy, often involving several weeks on crutches to allow the bone to heal in its newly corrected position.
Total Knee Arthroplasty
Total Knee Arthroplasty (TKA), or total knee replacement, is the treatment option for patients with severe, widespread damage across the knee joint. If arthritis is advanced, a realignment procedure alone may not be sufficient to relieve symptoms. TKA involves removing the damaged bone and cartilage and replacing the joint surfaces with metal and plastic components.
While TKA is a more extensive procedure than an osteotomy, it offers predictable correction of the leg alignment and reliable pain relief in cases of advanced joint degeneration. It is generally considered for older patients or those with severe, end-stage arthritis, where the priority is joint replacement rather than preservation. The decision between an osteotomy and a replacement depends on the patient’s age, activity level, and the extent of their joint damage.