Mako Orthopedic Systems (Stryker)

What This Technology Is

Mako is a robotic-arm assisted surgical system manufactured by Stryker Corporation, used primarily for orthopedic procedures including total knee replacement, partial knee replacement, and total hip replacement. The system combines preoperative CT-based planning with intraoperative robotic guidance to help surgeons position implants according to patient-specific anatomy.

The Mako system works differently from soft-tissue surgical robots:

• Preoperative planning: A CT scan of the patient's joint is used to create a 3D model and surgical plan before the procedure
• Haptic boundaries: During surgery, the robotic arm provides tactile feedback that resists movement outside planned bone resection zones
• Bone preparation: The surgeon uses the robot-assisted arm to prepare bone surfaces for implant placement

The surgeon maintains control of the instrument throughout the procedure. The robotic system does not cut autonomously but constrains and guides the surgeon's movements within planned parameters.

Where It Is Deployed

Mako systems are installed in hospitals and orthopedic specialty centers across North America, Europe, Asia, and other markets. Stryker reports over 2,500 systems installed globally as of 2024, with more than 2 million Mako procedures performed.

Primary applications:

• Total knee arthroplasty (TKA)
• Partial knee arthroplasty (PKA) / unicompartmental knee replacement
• Total hip arthroplasty (THA)

Robotic-assisted joint replacement has grown substantially in the U.S. market, with Mako representing a significant share of orthopedic robotic procedures.

Known and Documented Failure Modes

FDA MAUDE reports and orthopedic literature have documented failure patterns in Mako and similar systems:

Planning and registration errors

• Misalignment between preoperative CT-based plan and actual patient anatomy during surgery
• Registration failures requiring re-registration or conversion to manual technique
• Errors in bone landmark identification affecting plan accuracy

Hardware and mechanical issues

• Robotic arm calibration errors
• Haptic boundary function failures
• System crashes or freezes during bone preparation
• Instrument tip wear affecting cutting precision

Clinical consequences documented in adverse event reports

• Bone cuts outside planned parameters
• Implant malpositioning despite robotic assistance
• Soft tissue damage during robotic bone preparation
• Procedures converted to conventional technique due to system failures
• Extended operative times for troubleshooting

Outcome considerations

• Studies comparing Mako-assisted to conventional joint replacement show mixed results regarding functional outcomes, complication rates, and implant longevity
• Radiographic accuracy (implant position on imaging) may differ from clinical outcomes (pain, function, patient satisfaction)

Oversight and Regulatory Context

Mako received FDA 510(k) clearance as a surgical robot system. Subsequent applications and expanded indications have followed the same pathway.

Oversight factors:

• No mandatory joint replacement registry in the U.S.: Unlike some countries (UK, Australia, Sweden), the U.S. lacks a comprehensive national registry tracking implant performance by device and surgical approach
• Limited comparative effectiveness requirements: FDA clearance does not require demonstrating superiority to conventional technique
• Cost considerations: Mako procedures involve capital equipment costs, per-procedure fees, and required CT imaging, affecting institutional economics and potentially patient access

The American Joint Replacement Registry (AJRR) collects voluntary data from participating institutions but does not have universal coverage.

Why This Matters

Joint replacement is among the most common elective surgeries performed worldwide, with volumes expected to increase as populations age. The promise of robotic assistance is more consistent implant positioning, potentially leading to better function and longer implant survival.

Whether this promise is realized in practice depends on:

• Quality of preoperative imaging and planning
• Accuracy of intraoperative registration
• Surgeon skill in using the system effectively
• Whether positioning precision translates to meaningful clinical benefit

For patients, relevant questions include:

• Does their surgeon have sufficient experience with the robotic system?
• What are outcomes at their specific institution?
• Is robotic assistance supported by evidence for their specific condition and implant choice?
• What happens if the system malfunctions mid-procedure?

External Resources

• FDA MAUDE Database — Searchable adverse event reports
• American Joint Replacement Registry — Voluntary outcome tracking

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