Introduction
Tibial bowing is a clinical condition seen as the bowing of the bone in the lower leg (tibial bone), in the growing end away from the joint (diaphyseal end). This bowing of the bone occurs in three different patterns due to three other causes. However, the real cause of this condition is unknown, and its prevalence is usually uncommon. It is commonly seen in infants and babies. The tibial bowing is generally fixed within the skeletal maturation age, during or before adolescence.
What Are the Types of Tibial Bowing?
Tibial bowing is classified into three different types as it is directed in three directions, each occurring due to various causes. The direction of these deformities are:
- Anteromedial Tibial bowing - Bowing is seen in the front and medial aspects of the bone. It is caused due to absence of the fibula and intensive hyperplasia (cell growth) of the fibula. Associated symptoms of this condition include decreased cell growth of the tartar bone (bones of the foot), fusion or shortening of the ipsilateral side of the femur bone, and deformity of the foot facing upward or downward.
- Anterolateral Tibial bowing - Bowing is seen in the front and off-side aspects of the bone. The causes are Melnick-Needles Syndrome and Blount’s disease, and the associated symptoms include a small face, narrow thorax, and growth disturbances. These conditions become prominently evident at the age of 8 to 12 years.
- Posteromedial Tibial Bowing - Bowing is seen in the backside and medial aspect of the bone and is caused by congenital or intra-uterine developmental disturbances, and the associated symptoms seen are high-arched feet.
What Causes Tibial Bowing?
Though the exact causes of tibial bowing are unknown, there are factors assumed to be the primary cause of these conditions.
- Anteromedial Tibial Bowing - It is caused due to congenital shortening of the leg length or missing bone (fibular hemimelia).
- Anterolateral Tibial Bowing - It occurs as a congenital bowing of the bone due to genetic disorders of the nerve tissue called neurofibromatosis.
- Posteromedial Tibial Bowing - It occurs due to the baby's position in the intrauterine life, presenting with bowing of the leg with a discrepancy in the length.
The other causes include:
- Habitual or physiological bowing.
- Malnutrition, like rickets.
- The trauma of fractures.
- The abnormal growth pattern of cells (dysplasia).
- Conditions like Blount disease (a condition affecting the growth pattern of the bones around the knee in children).
- Fibrous dysplasia (a state of the bone with an abnormal scar-like bone tissue growth).
- Abnormal embryonic developmental patterns.
How Is Tibial Bowing Seen Clinically?
Tibial bowing is observed due to its apparent clinical pattern present at the time of birth. The legs are seen tilted upwards, almost touching the front surface of the foot, while the pattern in posterior deformity is less prominent and can be found by examining the leg. The conditions present at birth are:
-
The upward tilt of the foot.
-
Curved or high-arched feet.
-
Shortened leg length.
-
Bent or twisted ankle.
-
Skin dimple.
How Is Tibial Bowing Investigated?
Both clinical and radiographic methods investigate tibial bowing:
Clinical Investigation:
In cases of tibial bowing, the lower limb appears to be bent upward, sideways, or backward. The deformation pattern indicates the bowing and the treatment modalities to be followed. One of the methods used for examining tibial bowing is the Galeazzi test which is primarily used for assessing hip function and dislocation and is also used for differentiating the disorders seen at the time of birth that results in limb length discrepancies.
Radiographic Investigation:
Radiographic investigations are done using X-rays to study the length of the bone, curvature deformity, direction and thickness, and shape of hip development. These changes are assessed from the age of 6 to 12 weeks.
Laboratory Investigation:
Although clinical and radiographic imaging is done, it is essential to run lab tests to rule out or find any deficiency leading to malnourishment-triggered tibial deformity. The metabolic tests are done to diagnose rickets (vitamin D deficiency) and to check serum calcium levels.
How Is Tibial Bowing Treated?
The treatment of tibial bowing includes the following:
Conservative Management:
Tibial bowing is conservatively or non-surgically managed when mild to minimal deformity is around two to three percent. The conservative treatments provided are:
-
Splinting.
-
Serial casting- A treatment where the patient is provided with a few sets of casts which the patient wears at the interval of three to seven days, set until the desired outcome is achieved.
Tibial bowing shows a good prognosis and gets corrected primarily on conservative management. However, persistent deformity remains, with the maximum correction within two years. If the deformity is persistently more than ten years of age, then it is indicated for surgical management.
Surgical Management:
Surgical correction is indicated in cases with more than five percent deformities, visible leg length discrepancies, and patients older than ten with persistent, prominent deformities. The surgical management is done by lengthening the deformed limb or shortening the longer limb. Equalizing limb height shows a drastic improvement in movements and appearances.
Rehabilitative Management:
The rehabilitation of tibial bowing is done by providing the patient with sole shoe inserts, healed shoes, and strengthening exercises collateral with conservative management methods. Continued monitoring is required every six months to achieve deformation as minimal as one centimeter during skeletal maturity.
What Are the Complications of Tibial Bowing?
Some complications related to tibial bowing are:
-
Compromised Gait - People with tibial bowing show a very unstable or strained walking pattern due to curvature of the bone.
-
Postural Instability - Because of the bowing of the bone, there is a compromise in the posture to stand erect as there is incompetence in the length of the legs.
-
Visible Height Discrepancy - It is seen because of the uneven limb length between both legs.
What Are the Other Conditions Similar to Tibial Bowing?
Tibial bowing is often confused with fibular bowing, intrauterine fractures, and osteogenesis imperfecta (a clinical condition due to genetic disorders characterized by limb bending).
Conclusion
Tibial bowing is a clinical condition seen predominantly in children due to congenital deformity or associated syndromes. The treatment aims to provide a minimum deformation achieved by both conservative and surgical treatment. Although fixing the leg length deformity cannot be entirely resolved, the maximum equalization of the length is achieved without any visible discrepancies. All the treatments and rehabilitation methods help improve the patient's quality of life.
