2015 ISAKOS Biennial Congress ePoster #1710

Conventional Plate Fixation vs. PEEK Intraosseous Implants in Proximal Tibial Osteotomy

Mario Hevesi, MD, Rochester, MN UNITED STATES
Elizabeth A. Arendt, MD, Minneapolis, MN UNITED STATES
Jeffrey A. Macalena, MD, Minneapolis, MN UNITED STATES

University of Minnesota, Minneapolis, Minnesota, USA

FDA Status Cleared

Summary: Proximal tibial osteotomy (PTO) via conventional plate fixation was compared to PTO via PEEK intraosseous implant in order to evaluate and compare respective complication rates, efficacy of correction, effect on patellar height, and patient implant tolerance and retention in this retrospective cohort study.

Rate:

Abstract:

Background

Proximal tibial osteotomy (PTO) has been shown to be effective for varus correction of medial compartment degenerative disease and is also used in cartilage and ligament surgery with concurrent malalignment. Multiple PTO implants have been developed – conventional plate and screw (CPS) was popular initially whereas PEEK intraosseous implants (PII) have gained recent popularity.

Hypothesis

CPS and PII will be equivalent at correcting varus deformity.

STUDY DESIGN
Retrospective cohort study.

Methods

44 PTO cases—22 CPS, 22 PII—were reviewed from a preoperative baseline to a mean of 12 months radiographically (range: 4-37) and 20 months clinically (range: 13-33). Seven imaging measurements (limb mechanical axis, weight bearing line location along the tibial plateau (WBL), femoral axis-femoral condyle angle (FAFC), tibial plateau-tibial shaft angle (TPTS), tibial slope, Insall-Salvati ratio (ISR), Caton Deschamps index (CDI)) where recorded alongside complications, including those involving implant removal.

Results

At 0-6 months, both cohorts showed significant WBL, TPTS, and axial deformity improvements. CPS corrected from a mean axial deformity of 5.5° to -0.5° (p<0.0001) whereas PII corrected from 6.6° to -1.6° (p<0.0001).

CPS did not alter ISR and CDI at 0-6 months but affected both measures at 6-12 and 12-26 months (p<0.01). PII affected ISR throughout followup (p<0.05 at 0-12 months) without significantly perturbing CDI. Neither implant affected FAFC or tibial slope. At 12-26 months, remaining patients had deformities of 1.45° (CPS) and -1.60° (PII). At 24 months, 8 CPS implants had been removed (4 pain +/- instability, 4 subsequent reconstructive surgery) whereas all PII implants were in place, suggesting better PII implant tolerance by patients. Of note, PII implants are drillable, allowing for subsequent reconstruction without removal.

Conclusion

PII was found to be effective at maintaining axial correction with concurrent decreased patellar height perturbation and increased implant retention compared to CPS.