Will My Child Need Surgery for Bowed Legs in CHH?

The short answer is no—your child will not definitely need surgery. While bowed legs (genu varum) are one of the most common orthopedic issues in children with Cartilage-Hair Hypoplasia (CHH), the severity varies from child to child ^[1]. Some children have mild bowing that only requires careful monitoring, while others develop more significant bowing that needs surgical intervention to prevent joint damage and improve mobility ^[1][2]. In one major study, about 25% of individuals with CHH eventually required orthopedic surgery, most often to correct leg bowing ^[1].

Why Does CHH Cause Bowed Legs?

CHH involves a condition called metaphyseal dysplasia ^[3]. The metaphysis is the wide part of the bone near the joint where the growth plate is located. In CHH, genetic changes affect how cartilage cells develop in these growth plates ^[4]. Instead of growing straight and organized, the bone at the metaphysis can become disorganized, flared, and irregular (sometimes described as “fraying and splaying” on X-rays) ^[5][3]. Because the bone is not growing uniformly, the legs can gradually bow outward (genu varum) or, less commonly, inward (genu valgum) under the weight of the body ^[5][1].

Monitoring Mild Bowing

If your child’s bowing is mild and not causing pain or difficulty walking, the orthopedic team will likely recommend “watchful waiting.” This involves:

• Regular Clinical Exams: Checking your child’s gait (how they walk), joint laxity (looseness), and leg alignment, typically every 6 to 12 months ^[2].
• X-ray Monitoring: Periodic standing X-rays to measure the exact angle of the bones and see if the bowing is progressing ^[5].
• Symptom Tracking: Your doctor will look for signs of early wear-and-tear on the knee or ankle joints ^[1]. At home, you can watch for changes such as your child complaining of knee pain, starting to waddle or limp, or getting unusually tired when walking or playing.

Note on Bracing: Parents often ask if physical therapy or leg braces can fix the bowing without surgery. While bracing is used for some childhood conditions, it is generally not effective for bowing caused by structural skeletal dysplasias like CHH.

Surgical Options

If the bowing is severe, getting worse, or making it difficult for your child to walk, your doctor may recommend surgery. The goal of surgery is to straighten the legs, relieve pressure on the joints, and improve mobility ^[1][6]. There are two main approaches:

Guided Growth (8-Plates)

For growing children, surgeons often use a less invasive procedure called guided growth (or hemiepiphysiodesis) ^[1]. Small metal plates, sometimes called 8-plates because of their shape, are attached to one side of the growth plate ^[7].

• How it works: The plate temporarily acts like a tether, slowing down growth on the longer side of the bone while the shorter side continues to grow. Over time, the leg gradually straightens itself as the child grows ^[8].
• What to expect: This is usually an outpatient surgery with a rapid return to weight-bearing and normal activities. However, because children with skeletal dysplasias have abnormal growth plates, the results can be less predictable than in children without CHH ^[9]. Once the leg is straight, the plates are usually removed, but there is a risk that the bowing could return (rebound deformity) as the child continues to grow ^[7][10].

Corrective Osteotomy

If a child has very little growth remaining, or if the bowing is too severe for guided growth, a corrective osteotomy may be necessary ^[1][6].

• How it works: The surgeon carefully cuts the bone, straightens it into the correct alignment, and holds it in place while it heals. This is done using internal metal plates and screws, or sometimes an external fixator (a metal frame on the outside of the leg connected to the bone with pins) ^[11]. While external frames can look intimidating, children usually adapt to them surprisingly well during the healing process.
• What to expect: This is a more complex and invasive surgery than guided growth ^[11]. Recovery is longer, often requiring several weeks in a cast or frame with limited weight-bearing, followed by intensive physical therapy to regain strength and motion. However, it allows the surgeon to correct multiple deformities at once (such as bone twisting) and provides an immediate correction of the leg’s alignment ^[12].

Looking Ahead

Orthopedic management in CHH is highly individualized ^[2]. By establishing care with an experienced pediatric orthopedic surgeon—ideally one familiar with skeletal dysplasias—you can ensure your child gets the right intervention at the right time.