SLR - November 2014 - Zeno Pfau

Medial Malleolar Screw Versus Tension-band Plate Hemiepiphysiodesis for Ankle Valgus in the Skeletally Immature

References: Matthew D. Driscoll, Judith Linton, Elroy Sullivan, Allison Scott. Medial Malleolar Screw Versus Tension-band Plate Hemiepiphysiodesis for Ankle Valgus in the Skeletally Immature. J Pediatr Orthop.  2014 June;34(4): 441-6.

Scientific Literature Review

Reviewed By:
Zeno Pfau, DPM
Residency Program: North Colorado Podiatric Medicine and Surgery Residency,  Greeley, CO

Podiatric Relevance: Pediatric ankle valgus may progress with growth and lead to early ankle arthritis. A common approach to surgically correct the deformity in this population is guided growth obtained through medial hemi-epiphysiodesis. Successful results have been reported with both medial malleolar transphyseal screw (MMS) and the tension-band plate (TBP) hemi-epiphysiodesis techniques. However, the two techniques have not been directly compared. This study was designed to compare MMS and TBP outcomes in respects to the rate of deformity correction and frequency of complications.

Methods: In this retrospective study, 60 ankles (42 patients) in valgus alignment were compared between surgical correction through MMS and surgical correction through TBP hemi-epiphysiodesis. Rate of deformity correction and the frequency of complications between the two groups were analyzed. The data was collected from January 1, 2005 to November 1, 2010 from a pediatric orthopaedic specialty hospital. Documentation obtained included age at surgery, sex, underlying diagnosis, date of surgery and subsequent hardware removal, concurrent surgical procedures, surgical and postoperative complications, and presence or absence of symptomatic hardware complaints. All patients were treated with a single cannulated 4.5mm transphyseal MMS or a 2-hole TBP. Radiographic analysis consisted of the tibiotalar angle being documented at baseline, treatment completion and final follow-up. Statistical analysis was performed using Microsoft Excel 2010 and SPSS version 19.0. The Student t test was used to compare tibiotalar angle. Complication rates were compared with the use of the Fisher exact test.

Results: The 35 ankles treated with MMS had a mean rate correction that was 50 percent faster with a rate of  0.55 degrees per month. The 25 ankles treated with TBP had a mean rate correction of 0.36 degrees per month. Surgical complications for the MMS group was 23 percent (8/35) which consisted of four cases of screw migration or bony overgrowth, two cases of hardware breakage, two cases of symptomatic hardware. Surgical complications were seen in 4 percent (1/25) of the TBP group with the case complicated by infection/hardware removal.

Conclusion: This study demonstrated that both the MMS and TBP hemi-epiphysiodesis techniques can achieve successful correction of ankle valgus. MMS was also shown to have a higher rate of deformity correction, while TBP had a lower rate of complications. Keeping this information in mind, it is important that clinical judgment is used when selecting the proper procedure for each individual patient.

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