Use of a Core Reamer for the Resection of a Central Distal Femoral Physeal Bone Bridge: A Novel Technique with 3-Year Follow-up

May 10, 2018|Surgery

Zachary K. Pharr, MD;John D. Roaten, MD;Alice Moisan, BSN, RN, CCRP;Derek M. Kelly, MD;Jeffrey R. Sawyer, MD

TAKE-HOME POINTS

Central physeal arrest of the distal femur is challenging, but this surgical technique provides an option for treatment.
Partial bone bridges can be resected, but advanced imaging with MRI or CT, or both, is helpful in preoperative planning.
Regardless of the type of physeal bar resection that is chosen, it is unlikely that complete, normal bone growth will be restored and closed follow up will be needed.

ABSTRACT

A central distal femoral physeal bone bridge in a boy aged 5 years and 7 months was resected with a fluoroscopically guided core reamer placed through a lateral parapatellar approach. At 3-year follow-up, the boy’s leg-length discrepancy was 3.0 cm (3.9 cm preoperatively), and the physeal bone bridge did not recur. The patient had full function and no pain or other patellofemoral complaints. This technique provided direct access to the physeal bone bridge, and complete resection was performed without injury to the adjacent physeal cartilage in the medial and lateral columns of the distal femur, which is expected to grow normally in the absence of the bridge.

A physeal bone bridge is an osseous connection that forms across a physis. It may cause partial premature physeal arrest. Angular deformity and limb-length discrepancy are the main complications caused by physeal bone bridges.^1-4 The indications for the treatment of physeal bridges are well documented.^1-5 Trauma and infection are common causes of distal femoral physeal bone bridges. Arkader and colleagues⁶ showed that among different types of physeal bridges, the Salter-Harris type is significantly associated with complications, among which growth arrest is the most common and occurs in 27.4% of all patients.

The treatment of distal femoral physeal bone bridges is technically difficult and provides variable results. Poor results are reported in 13% to 40% of patients.^7-10 Procedure failure has been attributed to incomplete resection with the persistent tethering and dislodgement of the graft.¹¹ Methods with improved efficacy for the removal of central physeal bridges will help prevent reformation after treatment. We have used a novel technique that allows the direct resection of a central physeal bone bridge in the distal femur through the use of a fluoroscopically guided core reamer. This technique enables the complete removal of the bone bridge and the direct visual assessment of the remaining physis. The patient’s parents provided written informed consent for print and electronic publication of this case report.

CASE

A 3-year-old boy with a history of hemifacial microsomia presented for the evaluation of genu valgum and leg-length discrepancy. His intermalleolar distance at that time was 8 cm. A standing radiograph of his lower extremities demonstrated changes consistent with physiologic genu valgum. He had no history of knee trauma, infection, or pain.

At the age of 5 years and 7 months, the patient returned for a repeat evaluation and was noted to exhibit the progressive valgus deformity of the right leg and a leg-length discrepancy of 3.9 cm (Figure 1).

Radiographs also showed the presence of a bone bridge of unknown etiology in the boy’s distal femoral physis. Computed tomography and magnetic resonance imaging (MRI) were used to characterize the size and location of the bone bridge, which was found to involve approximately 30% of the physis (Figures 2A-2C).

Using the multiplier method described by Paley and colleagues,¹² the patient’s projected leg-length discrepancy, assuming complete growth arrest, was approximately 10.2 cm. The risks and benefits of physeal bone bridge resection, including the high rate of recurrence, were discussed with the patient’s family, who wished to proceed with resection.

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References