Brittle Bone Disease: Osteogenesis Imperfecta Surgery and Care

Osteogenesis imperfecta (OI), widely known as brittle bone disease, is an inherited connective tissue disorder that makes bones unusually fragile. In a child with OI, a bone may break after a minor fall, an awkward twist or even an everyday task such as a nappy change. Care is long-term and shared between several specialists, combining fracture management, medical treatment to strengthen bone, physiotherapy and, when needed, osteogenesis imperfecta surgery to straighten and support bowed bones.

OI is one of the rare bone diseases of childhood, affecting roughly one in every 15,000 to 20,000 births. Its severity varies enormously, from mild forms that may go unrecognised until adulthood to severe forms with multiple fractures and marked bowing from birth. This article explains what causes OI, how it is diagnosed and, in particular, what orthopaedic treatment involves.

What is osteogenesis imperfecta and what causes it?

Bone strength depends not only on minerals such as calcium but also on collagen, the protein framework that gives bone its toughness. In most people with OI there is a change in one of the genes that make type 1 collagen (COL1A1 or COL1A2). As a result, the body either produces too little collagen or produces collagen with a faulty structure. Rather like a building with weak steel reinforcement, the bone breaks more easily under load and can gradually bend.

OI is usually inherited in an autosomal dominant pattern, which means that a parent with OI has a one-in-two chance of passing it on in each pregnancy. Many children, however, are the first in their family to be affected because of a new (de novo) genetic change. Some rarer types are recessive. For this reason, families are encouraged to see a clinical geneticist, whose advice is also helpful when planning future pregnancies.

Types of osteogenesis imperfecta

The classic Sillence classification describes four main types, and further types have since been defined on the basis of genetic findings. The type gives a general idea of how the condition is likely to behave, but two children with the same type can still be affected quite differently.

Signs and diagnosis

Which signs suggest OI?

• Fractures after minor injury: breaks caused by far less force than would be expected for the child's age, or repeated fractures.
• Bowing of the long bones: particularly the thigh bone (femur) and shin bone (tibia).
• Blue-grey sclerae: the whites of the eyes are thin, so the colour of the tissue beneath shows through.
• Dental problems: discoloured teeth that wear down or chip easily (dentinogenesis imperfecta).
• Joint laxity and muscle weakness: unusually flexible joints and delays in sitting or walking.
• Short stature and scoliosis: especially in moderate and severe forms.
• Hearing loss: usually starting in adolescence or adulthood.

How is OI diagnosed?

The diagnosis is based on the child's history, family history, examination and X-ray findings taken together. X-rays may show thin bones, old and new fractures, bowing and small extra bones in the skull (Wormian bones). Bone density scans (DXA) are useful for monitoring. Genetic testing is increasingly used to confirm the diagnosis and identify the type, although the clinical picture remains central.

There is one sensitive point that parents should be aware of. When a baby has several unexplained fractures, doctors have a duty to consider every possible cause in order to keep the child safe. This is a standard part of medical assessment, not an accusation. Reaching the correct diagnosis allows the child to receive the right care and brings an end to a very stressful period of uncertainty for the family.

What does orthopaedic care for OI involve?

There is currently no treatment that reverses the underlying genetic change. The aims of care are to reduce the number of fractures, control pain, correct deformity and help the child move as independently as possible. Treatment is therefore planned by a multidisciplinary team spanning paediatric orthopaedics, paediatric endocrinology, clinical genetics, physiotherapy, dentistry and ear, nose and throat care.

Treating fractures

Most fractures in children with OI are treated in the same way as other childhood fractures, with casts, splints or lightweight supports. The key difference is that long periods of immobilisation weaken bone further, so immobilisation is kept as short as possible, light protective splints are preferred and the child is encouraged to move again as soon as it is appropriate.

Medical treatment

In moderate and severe forms, medicines that increase bone density and reduce fracture frequency (for example, the bisphosphonate group) may be used. Which child receives which medicine, when and for how long is decided by a paediatric endocrinologist or metabolic bone specialist, and any orthopaedic surgery is timed to fit around this treatment.

Physiotherapy and daily life

Physiotherapy that builds muscle strength, maintains joint movement and teaches safe ways of moving is a cornerstone of care. Water-based exercise works the muscles without placing heavy loads on the bones, so it suits many children. Walking frames, orthoses or a wheelchair may be used when needed to support independence.

When is osteogenesis imperfecta surgery considered? Telescopic rods explained

Surgery is considered when the same bone keeps breaking, or when bowing makes it hard for the child to sit, stand or walk. During the operation the bowed bone is divided at one or more points (osteotomy) and realigned, and a rod is passed down the hollow centre of the bone. The rod acts as an internal splint, helping to hold the corrected alignment and limiting the effect of any future fractures.

In growing children, telescopic rods are often used. These consist of two parts that slide inside each other, so the rod lengthens as the bone grows. Compared with fixed-length rods, the aim is to reduce the chance of the child outgrowing the rod and needing a further operation to replace it. Even so, a rod may need to be exchanged or revised as the child grows, and this is an expected part of the treatment plan.

The timing of surgery depends on the child's age, the width of the bone, the stage of medical treatment and goals such as standing. As with other rare childhood limb deformities, this surgery requires careful planning. Children who develop scoliosis are followed jointly with a spinal surgery team.

Handling and safety at home

• When lifting a baby, place one hand under the bottom and the other under the back and head; never lift by the arms or legs.
• During nappy changes, support the baby under the bottom rather than lifting by the ankles.
• When dressing, ease clothing over the limb instead of pulling the arm or leg through.
• Use soft padding in car seats and pushchairs, and reduce fall hazards such as slippery floors at home.
• Ask your physiotherapist about suitable activities such as swimming; being overprotective can also lead to muscle weakness and bone loss.
• Agree a plan with the school and carers for what to do if a fracture is suspected.

When should you see a doctor?

In a child already diagnosed with OI, the following warrant an orthopaedic review:

• new pain, swelling or a change in shape of an arm or leg, or the child refusing to use a limb
• bowing that is clearly increasing or making standing harder
• a newly noticed curve in the back, or uneven shoulders or waist
• new neurological symptoms such as headache or neck pain, tingling in the hands or difficulty swallowing
• reduced hearing

In a child without a diagnosis, fractures from minor injuries, repeated fractures or a family history of similar problems are reasons to be assessed for OI. Prof. Dr. Halil İbrahim Balcı worked as a research fellow at the Paley Institute in the United States, focusing on deformity surgery, congenital bone anomalies and paediatric orthopaedics; treatment options are discussed with each family on the basis of the child's own findings.

Key points

• Osteogenesis imperfecta is a genetic condition, usually caused by changes in the type 1 collagen genes, that makes bones fragile.
• Severity ranges from mild to very severe; diagnosis relies on examination, X-rays and, where needed, genetic testing.
• Care is multidisciplinary, combining fracture management, medical treatment, physiotherapy and surgery when appropriate.
• For repeated fractures or bowing that limits function, osteotomy with telescopic rodding is an option in suitable patients.
• The right treatment is decided individually after examination and imaging, and the course varies from child to child.