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Patient-Specific Cutting Guides for Alignment-Correcting Osteotomy About the Knee: A Study of Accuracy, Cost, and
Ian Savage-Elliott1, Zachary I Li1, Naina Rao1
1Department of Orthopedic Surgery, New York University Langone Health, New York, New York, USA.
Background:
The utility and safety of patient-specific cutting guides (PSCGs) in osteotomies about the knee is uncertain.
Purpose:
To compare the cost, accuracy of radiographic correction, and safety of PSCG versus standard cutting guide (SCG) corrective osteotomies about the knee.
Study Design:
Cohort study; Level of evidence, 3.
Methods:
Patients undergoing high tibial osteotomy (HTO) or distal femoral osteotomy (DFO) were retrospectively reviewed from 2017 to 2022. Those who underwent 3-dimensional PSCG osteotomy were propensity matched to patients undergoing traditional osteotomies. Procedure time and fluoroscopic details were extracted from operative notes. Hip-knee-ankle (HKA) angle, posterior tibial slope (PTS), and mechanical axis deviation were measured on pre- and postoperative radiographs. Intraclass correlation coefficients were calculated to determine the reliability between the intended and resultant correction of HKA. Time-driven activity-based costing (TDABC) analysis was performed to compare procedure costs.
Results:
A total of 42 patients were included, with 11 HTOs and 10 DFOs in each group. Between the SCG and PSCG groups, respectively, final HKA (2.7° vs 1.9°; P = .36), PTS (9.6° vs 9.0°; P = .79), and mechanical axis deviation (10.2 vs 5.8 mm; P = .21) were similar. The intraclass correlation coefficient between the intended and measured HKA correction was 0.841 (good) in the PSCG group and 0.623 (moderate) in the SCG group. PSCG osteotomies had a mean procedure time that was 18.5 minutes shorter than SCG osteotomies (P = .39). Fluoroscopy time (43 vs 99 seconds; P < .001), tourniquet time (99.9 vs 116.6; P = .12), and radiation dose (2.9 vs 7.8 mGy; P = .01) were lower in the PSCG group. TDABC analysis demonstrated a total cost of $27,026 for PSCG and $27,100 for SCG. The rate of hinge fractures (9.5% vs 33.3%) and return to the operating room (4.8% vs 19.0%) were lower in the PSCG group, although these differences were nonsignificant.
Conclusion:
Both traditionally guided osteotomies and PSCG-guided osteotomies accurately corrected lower extremity malalignment. Utilization of PSCG resulted in similar procedure times and cost, as well as less fluoroscopy and lower tourniquet time, compared with conventional osteotomy. PSCG trended toward a decreased rate of postoperative complications.
