MAKO Robotic Systems (Stryker)

What is the MAKO Robotic Arm-Assisted System?

MAKO is an advanced robotic-arm platform that operates under the direct control of the surgeon while acting as a fail-safe to prevent intraoperative technical errors. It utilizes pre-operative Computed Tomography (CT) scans to reconstruct an exact 3D volumetric model of the patient’s knee or hip joint and integrates haptic feedback (tactile guidance) technology to ensure maximum surgical precision.

Clinical Efficacy: What Does MAKO Do?

• Patient-Specific Pre-Operative Planning: Utilizing the pre-operative CT scan, the software allows the surgeon to virtually simulate and calculate the ideal alignment, rotation, and orientation of the implant based on the patient’s unique bone morphology.
• Virtual Boundaries (Safe Zone): The system establishes a digital “boundary wall” around the designated bone resection area. If the surgeon attempts to move the cutting tool outside this pre-mapped safety zone, the robotic arm immediately resists or locks.
• Soft Tissue Preservation: Bone preparation is strictly confined to the pathological areas, ensuring maximum protection of adjacent collateral ligaments, neurovascular structures, and healthy soft tissue.

Step-by-Step Clinical Workflow: How is MAKO Utilized?

The deployment of the MAKO system is a highly structured, three-phase technological process that begins days before the actual surgery. The surgeon directs the robot through an integrated master-assistant relationship.

Phase 1: Pre-Operative Patient-Specific Architectural Planning

Before the patient enters the operating room, the software completely maps the native joint anatomy.

• CT Acquisition: High-resolution Computed Tomography scans of the target joint (knee or hip) are acquired.
• 3D Volumetric Modeling: The DICOM data from the CT scan is processed by the MAKO software to reconstruct a 1:1, patient-specific 3-dimensional virtual model of the bony anatomy.
• Virtual Rehearsal: The surgeon positions the virtual components onto this 3D model, planning the exact implant sizing and calculating the precise depth of bone cuts in millimeters. Essentially, the geometry of the surgery is finalized digitally.

Phase 2: Intraoperative Registration and Navigation

Once the procedure begins, the surgeon must synchronize the virtual pre-operative plan with the physical anatomy of the patient on the operating table.

• Anatomical Registration: Using a specialized electronic registration probe, the surgeon samples specific reference points on the surface of the patient’s bone.
• Optical Tracking: Near-infrared (NIR) tracking cameras in the operating room continuously monitor optical arrays attached to the patient’s bone and the robotic arm with sub-millimeter accuracy. This confirms that the digital model and the physical bone are perfectly aligned in space.
• Ligamentous Laxity and Gap Balancing: The surgeon manipulates the joint through its range of motion to measure ligament tension. If subtle real-time modifications are required, the plan can be dynamically updated on the console.

Phase 3: Resection via Robotic Arm and Haptic Constraints

This phase represents the core technological advantage of the MAKO system.

• Robotic-Arm Control: The surgeon manually guides the surgical instrument attached to the distal end of the robotic arm. The robot does not perform autonomous movements; it moves strictly in tandem with the surgeon’s hand.
• Haptic Feedback: As the bone cuts are executed, the robotic arm provides smooth tactile movement exclusively within the pre-planned “green zone” shown on the display.
• Automated Safety Cut-Off: If the tool inadvertently approaches the boundaries of the safe zone (toward critical ligaments or neurovascular bundles), the robotic arm creates physical resistance—resembling a solid wall—and instantaneously deactivates the cutting burr or saw tip.

Comparative Modality Matrix