Abstract
Background
Discrepancies in patient outcomes after total knee arthroplasty have encouraged the development of different treatment options including early preventive interventions. In addition, improvements in surgical techniques and instrumentation have increased the accuracy of the surgeries. In this case study, we review the first robotic-arm assisted modular tricompartmental knee arthroplasty in which bone and soft tissues are conserved by employing a precise planning and execution technique.
Materials and Methods
A 63 year old Caucasian female with a Body Mass Index (BMI) of 27 presented to the surgeon (SK) with knee pain and a varus mechanical alignment. The patient received modular tri-unicompartmental arthroplasty performed with robotic-arm assistance; (see figure 1 for post-op radiograph). Range of Motion (ROM), Knee Society Score (KSS) and Knee Injury and Osteoarthritis Outcomes Score (KOOS) were measured pre-operatively and post-operatively at 6, 16, and 23 months. At 6 months post-op an in-depth in vivo kinematic analysis was conducted by using a validated fluoroscopic assessment technique [1]. The patient simulated stair climbing, kneeling activity, and deep lunge while under single plane fluoroscopy. Three dimensional models were created from CT scans and were matched to 2D fluoroscopic images for kinematic assessment.
Results
ROM, KSS, KOOS improved post-operatively, see Table 1. Patient displayed tibial internal rotation and screw home mechanism like that of normal knees, (Figure 2). Anterior-posterior translation of medial and lateral compartments was observed (Figure 3). The patient demonstrated a maximum flexion of 115 and 114.9 in kneeling and lunge activity, respectively. Tibial external rotation was seen in both kneeling and lunging, although rotation was greater during the lunge activity (3.1 versus 11.5 degrees). Both medial and lateral compartments showed posterior translation during these activities (Table 2).
Conclusion
Clinical, radiographic and functional outcomes were achieved for this patient. This case report was the first case of robotically assisted, modular, ACL and PCL sparing tricompartmental arthroplasty. It was anticipated that preserving more soft tissues, particularly the ACL would contribute to improved kinematic function of the knee following arthroplasty, which was the primary differentiating factor between a bicompartmental design and a traditional tricompartmental knee design. The use of robotic techonlogy as described herein has not yet been approved by the FDA.
