Description
IS RADIOGRAPHIC ASSESSMENT OF IM ALIGNMENT ON THE FIRST POSTOPERATIVE DAY OF ROBOTIC TKA RELIABLE?
F. LACAZE, ORTHOSUD, St Jean de Vedas, France
Topic: Knee - Joint Replacement
Objectives: Restoration of the native anatomy after TKA represents the grail for any MI surgeon. With this in mind, pre-operative planning, adjustment of implant positioning according to ligament balance, and respect for the height and orientation of the joint space all contribute to our decision-making algorithm. Post-operative alignment in the frontal plane allows us to assess whether the initial objectives have been met. Bipodal telemetric imaging under load is part of this assessment.
Can these images be taken the day after the operation? Are they reproducible?
We hypothesised that these large radiographic images could be taken under load and that they were reliable.
Methods: 110 successive TKAs performed using the Mako robotic assistance system. This series concerned primary gonarthrosis, excluding revision, osteotomy or previous fractures. 95 complete files (quality radiographs available on D1 and D90). Single centre, single operator, Oct 2021-June 2022. Composition of the study group (95): 65 women, 30 men, age 70±8 (49, 87), BMI 28.7±5.1 (19.5, 40.3)
Pre-op HKA 177.1±6.2(165.0, 190.3). Pre-op MPTA 87.9±3.3(80.4, 96.4). Pre-op DLFA 88.5±2.8(83.3, 98.2). JLCA pre-op 2.0±3.9 (-6.5, 9.8). JLOA pre-op 0.8±3.1 (-6.4, 9.6).
Triathlon/Stryker type TKA, CR, uncemented. Reverse kinematic alignment (iKA), no ligament release in this series. Triple anaesthetic modality: local by intraoperative injection, locoregional by femoral catheter to the adductor canal and IPACK and finally general or spinal anaesthesia. Systematic uprighting and walking before radiographic imaging to ensure the feasibility of the radiographic procedure and limit patient apprehension.
Evaluation criteria: HKA, PMTA, DLFA, JLCA, JLOA assessed by loaded bipodal telemetric films at D1 and D90. Prospective data collection and retrospective analysis.
Results: HKA D1 178.6±2.5 HKA D90 178.5±2.6 tTest p=0.82
PMTA J1 87.2±2.1 PMTA J90 87.3±2.1 tTest p=0.64
DLFA J1 88.6±2.0 DLFA J90 88.9±1.9 tTest p=0.82
JLCA J1 0.1±0.7 JLCA J90 0.0±0.8 tTest p=0.60
JLOA J1 -2.0±2.8 JLOA J90 -0.2±2.7 tTest p=0.00005*
7 radiographic examinations not feasible, 6 not interpretable and 2 patients lost to follow-up.
In a context of optimised anaesthesia and adapted physiotherapy management, the feasibility of large radiographic images under load is proven. Only 13 examinations (12%) could not be finalised, performed or interpreted under satisfactory conditions the day after the operation. The reproducibility of the measurements was satisfactory, apart from the obliquity of the joint space in this series.
Conclusions: Post-operative telemetric imaging on Day 1 is feasible in most cases. Their reliability is proven in this series in comparison with measurements taken at D90 to characterise the alignment obtained in the frontal plane outside the obliquity of the joint space (JLOA).
