Hemiepiphyseal procedures that permanently or temporarily arrest half of the epiphysis are useful in correcting angulatory deformity in the growing child. Staples across the epiphysis provide temporary arrest and allow growth once removed. Hemiepiphysiodesis is permanent and requires careful timing to avoid over- or undercorrection.
Hemiepiphysiodesis requires careful timing and follow-up. The advantages are a small scar and a single procedure.
Technique Under imaging visualization, use a K wire to identify the medial or lateral margin of the epiphyseal plate. Make a stab incision. Place a 6-mm drill through the stab wound and just enter the growth plate. Inspect the drilling for cartilage to confirm physeal entry. Through this drill hole, place a small curette into the margin and perform a shallow curettage to remove the cortex and about a centimeter of underlying epiphysis.
Postoperative care Place a compressive dressing. Inject local anesthetic. The patient usually is discharged the same day. Follow clinically about every 3–4 months. If correction occurs before skeletal maturity, complete the epiphysis to avoid overcorrection.
Stapling requires less accurate timing but a larger incision and a second procedure for staple removal. The procedure is ideal for correcting deformities such as idiopathic genu valgum. Note the deformity before stapling and just before the staples were removed.
Technique Under imaging, using a K wire, mark the level of the physis. Make a 3–4-cm longitudinal incision to expose the periosteum over the site of the physis. Being careful not to damage or penetrate the periosteum, and using an image intensifier, place a reinforced staple across the physis at the midportion of the bone, following the slope of the physis. Leave the base of the staple extraperiostal. Place a second and possibly a third staple spaced about 2–3 cm apart across the plate, again avoiding a deep penetration. Document the position of the staples with AP and lateral radiographs. Close the wound with subcuticular skin sutures. Place a compressive dressing.
Postoperative care Follow the patient at 3–4 month intervals. When correction has occurred, remove the staples. Correction usually occurs at a rate of about 1° per month. Although staples rarely cause physeal closure, follow for this complication. If physeal arrest occurs, consider physeal bar resection and fat graft interposition or completion of the epiphysiodesis.
Hematoma Reduce risk by a compressive dressing following surgery.
Overcorrection Avoid by proper timing of staple removal or completing the epiphysiodesis in the hemiepiphysiodesis.
Undercorrection The procedure is performed too late.
Staple back-out If this occurs, reinsert.