Equalizing leg length by “lengthening the shorter leg” by surgery: a case report

S. Chockalingam*, Alagumalai

Department of Orthopedics, Kauvery Hospital, Trichy, India

Background

Limbs can be unequal in length due to many reasons. Common causes are trauma leaving one leg shorter, infection of bone affecting growth in a child and congenital deficiency of growth of one limb. Congenital deficiency of growth of one limb has different sub types. We will limit to “congenital lower limb discrepancy” in this article.

One leg can be shorter than the other either in the thigh bone, or tibia bone or a combination of both. Specific conditions go by different names. They are proximal focal femoral deficiency, tibia hemimelia and fibular hemimelia. Fibular hemimelia is a common condition with partial or complete deficiency of fibular growth associated with tibial shortening. They can be associated with deformities of foot, knee or hip or combination of these.

Case Presentation

We describe a 10-year-old boy who presented with shortening of 4.5 cm. He had limping and had started developing back pain due to imbalance in the spine due to this leg length difference. His clinical assessment and x rays are shown here.

They confirm his difference to be in the leg segment with shortening of tibia.

Leg length difference can either be static or progressive. The difference will usually be progressive in congenital limb length discrepancy. This means that his 4.5cm shorter leg will get worse with growth. Hence, we counselled the family with different treatment options. As the shortening is 4.5cm, shoe raise was prescribed to balance his spine and walking. It was however unacceptable in the long run as the shortening will increase with his growth. Normal leg shortening either by acute shortening or by growth arrest procedure, though are options, are not advisable in this age. These normal leg procedures are usually done after and around the age of 14 years.

Lengthening of the affected leg by gradual distraction was advised. Child and parents were explained in detail and surgery was performed. Anesthesia was regional with spinal epidural analgesia. The surgery involved the following steps:

Division of fibula and excision of small segment.
Application of external fixator frame with pins passing through tibia and fibula.
Division of tibia, called corticotomy.
Closure of surgical wounds and dressing of pin sites.

The patient had adequate pain relief post operatively. His leg was elevated to prevent swelling and to facilitate wound healing.

Gradual distraction of the bone at the corticotomy site was commenced on day 4. The two parts of tibia were distracted apart at a rate of 1mm per day. The distraction was done in four increments in a day six hours apart which equated to 0.25mm per distraction maneuver. This was tough to the parents and the child. This distraction was done by the child and his parents and they were taught the method. He tolerated these maneuvers well. He was discharged on day 7th post op day.

He had regular review with repeated x rays to monitor continuation of distraction. These are shown in the follow up x rays with gradual increase in the gap between the two ends of tibia

The new bone gradually forms as a soft callus and fills the gap.

He achieved the intended distraction of 4.5 cm in 45 days. Then the distraction was stopped. The frame was kept to support the growing bone to consolidate for another 90 days. This equates to 30 days per cm of bone grown. During the entire period, the boy did exercises for the knee, foot and ankle. He was also mobilizing with a frame and was independent walker with assistance of the frame.

The x ray dated 25.06.2021 shows the bone to consolidated well enough to remove the frame. The removal of frame was done with short anaesthesia.

He subsequently mobilized with a walker and exercises his knee and foot and ankle.

Discussion

Congenital leg length discrepancy is not an uncommon condition in the general population. Due to the varying severity of this condition, children may not come to treatment depending on the symptoms or absence thereof. Fibular hemimelia is a common condition causing this discrepancy.

Fibular hemimelia may result in difference of leg length ranging from 1.5 cm to as much as 6 to 7 cm. Depending on the magnitude, a simple shoe raise to equalize the difference is advised. In our patient, the difference was significant enough to warrant surgery.

Leg lengthening by distraction is called distraction osteogenesis. Though this surgery has been reported in the literature originally back in ———–, advances in external fixation and internal lengthening procedures in the past three decades, have standardized this procedure.

External fixation devices are two types, monoliteral fixators and ring fixators. We used ring fixator, concepts and design by the Russian Surgeon, Gavrii abramovich llizarov. This device helps in good control of the bones during distraction, with minimal morbidity. Due to multiple pins, involved in fixing the bones as compared to mono lateral fixators, the patient compliance is essential for the successful outcome.

Conclusion

We have demonstrated with our case report that the difference in leg length can be managed by biological process of growing bones with gradual distraction. We feel that sharing this case report will improve awareness among the doctors at large of this surgical procedure and successful outcome.

Dr. S. Chockalingam

Senior Consultant – Orthopaedic Surgeon

Equalizing leg length by “lengthening the shorter leg” by surgery: a case report

Equalizing leg length by “lengthening the shorter leg” by surgery: a case report

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