Beyond Achondroplasia

Growing together with Clara

Clinical outcome of lower limb lengthening


This recent publication : “The etiology of short stature affects the clinical outcome of lower limb lengthening using external fixation“, by  S.Kim et al, Department of Orthopaedics, New Jersey Medical School, published in March 2014, the authors made a systematic review of the literature of 18 trials involving 547 patients.

They performed a systematic review of the literature pertaining to lower limb lengthening using external fixation for short stature. The most interesting point of this review was the authors assessed whether different underlying diagnoses are associated with varied clinical outcomes in these patients.

The documented clinical outcomes included:

1. Amount of lengthening

2. Healing index (HI),

3. Complications based on the underlying diagnosis for the short stature

The results for the review of 18 clinical studies, with 547 patients who underwent 1,581 lower limb segment lengthening procedures were the following:

a) Mean follow-up was 4.3 years.

b) The average age at lengthening was less for individuals with achondroplasia/hypochondroplasia (A/H) (14.5 years) than for those with Turner’s syndrome (TS) (18.2 years) or with constitutional short stature (CSS) (21.7 years).

c) Mean height gained was greater in patients with A/H (9.5 cm) than in those with TS (7.7 cm) or CSS (6.1 cm) group.

d) The Healing index was better in A/H (30.8 days/cm) and CSS (32 days/cm) than in TS (45.1 days/cm).

e) The reported complication rate per segment was lower for A/H (0.68) and TS (0.71) than for CSS (1.06).

After this review, authors concluded that patients with Achondroplasia/Hypochondroplasia tolerated larger amounts of lengthening with fewer complications than those with other diagnoses.

This report is not a comparison of which condition is best. It’s a report for the confirmation of good outcomes for limb lengthening in achondroplasia. At this point, the authors did a review for external fixators.

The following is an excerpt of the excellent extensive review : “Progress in and from Limb Lengthening“, Dror Paley, March 2014

“While the history of limb lengthening goes back more than one century, its biggest advances have all occurred in the past 25 years. Its foundations were set by the pioneering, landmark original work, and ideas of Gavril Abramovich Ilizarov. Ilizarov’s original ideas have been corroborated and reproduced by surgeons all over the globe.
Ilizarov deserves the credit for bringing science to this field. The past 25 years are also bountiful in new ideas, new devices, and new therapeutics. Distraction histogenesis is still a young field of study. There is still a lot of room for innovation and advances.
While the first 100 years was the story of external fixation and distraction osteogenesis, the next 100 years will be the story of implantable distraction devices, biofeedback controls for internal and external fixation, and the modulation of molecular biology, and regenerative biology to orthopedicsMany of the genetic conditions currently being treated will have medical instead of surgical solutions and new applications of distraction biology will be found.”

For a next post, I will write about different methods of internal fixators used for limb lengthening:

a. Betzbone
b. LON (lengthening over nail)
d. Fitbone

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