Kambiz Behzadi
November 24, 2025
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Surgeon Assembly Technique
Electronic Signature Sizing and force/torque sensors as method for quantitative sizing of bone in press fit arthroplasty
How an we make press fit arthroplasty more reliable?
The Electronic Signature Sizing of Bone (ESSOB) technology represents a transformative advancement in orthopedic surgery, addressing a critical gap in total hip replacement (THR) procedures. Currently, 50% of THR failures stem from improper bone sizing during press fit implant preparation—a procedure that relies entirely on surgeons’ subjective auditory, tactile, and visual assessment. With 800,000 of the 1 million annual THR surgeries worldwide performed by surgeons conducting fewer than 10 procedures per year, ESSOB offers a quantitative, standardized solution that can democratize surgical excellence and dramatically improve patient outcomes.
Current State of Press Fit Arthroplasty
Press fit arthroplasty remains fundamentally unchanged since its inception—surgeons prepare a bone cavity approximately 1mm smaller than the implant diameter and impact it into position. The success depends entirely on achieving optimal primary stability through interference fit, maintaining less than 50μm of micromotion at the implant-bone interface.
The Goldilocks Dilemma
Bone behaves as a stiff circular composite spring with distinct elastic properties:
Currently, surgeons navigate this critical balance using only qualitative sensory feedback—listening for pitch changes, feeling resistance, and observing bleeding bone. This subjective approach yields inconsistent results, particularly for less experienced surgeons who perform the vast majority of procedures globally.
Core Innovation
ESSOB transforms bone preparation from art to science by monitoring real-time electrical signatures of driving motors during reaming and broaching. The technology operates on a fundamental principle: the implant-bone interface acts as a variable rheostat, causing measurable changes in current and power consumption that directly correlate with bone elasticity and contact conditions.
Dual-Mode Sensing Architecture
Power Absorption Mode
Power Transmission Mode
Advanced Signal Processing
The system incorporates Kalman Filter algorithms (including Extended and Unscented variants) to:
Immediate Applications
Intraoperative Guidance System
Standardization Protocol
Extended Capabilities
Multi-Joint Applications
Modular Assembly Optimization
Clinical Benefits
Economic Value Proposition
Competitive Advantages
Phase 1: Clinical Validation (Months 1-12)
Phase 2: Regulatory Approval (Months 12-24)
Phase 3: Market Launch (Months 24-36)
Phase 4: Platform Expansion (Months 36+)
Technical Development Priorities
Commercial Strategy
Regulatory Approach
ESSOB represents more than incremental improvement—it fundamentally transforms how surgeons approach press fit arthroplasty. By providing objective, quantitative measurements of bone elasticity and contact conditions, ESSOB eliminates the guesswork that currently plagues orthopedic surgery.
The technology’s immediate impact will be measured in prevented fractures, reduced revisions, and billions in healthcare savings. However, its ultimate legacy lies in democratizing surgical excellence—ensuring that every patient, regardless of their surgeon’s experience level, receives optimal care.
As orthopedics advances toward personalized, data-driven medicine, ESSOB provides the foundational technology for this transformation. The question is not whether quantitative bone sizing will become standard of care, but how quickly the orthopedic community will embrace this paradigm shift.
The convergence of clinical need, technological readiness, and economic imperative creates an unprecedented opportunity. ESSOB is positioned to become the gold standard for press fit arthroplasty, establishing a new era of precision, consistency, and excellence in orthopedic surgery.
For more information on ESSOB technology and partnership opportunities, contact Autonomous Orthopedics.