Gait Recovery Following ORIF for a Unilateral Comminuted Intra-Articular Calcaneal Fracture: Objective Longitudinal Assessment Using Smartphone-Based MediaPipe Gait Analysis

Technical Summary: Gait Recovery Following ORIF for a Unilateral Comminuted Intra-Articular Calcaneal Fracture

Problem Statement
Unilateral comminuted intra-articular calcaneal fractures, often resulting from high-energy axial loading, present significant challenges in treatment and rehabilitation. Despite successful Open Reduction and Internal Fixation (ORIF), patients frequently suffer from persistent pain, restricted hindfoot motion, and long-term gait abnormalities. A critical barrier to effective rehabilitation is the limited access to objective, quantitative outcome assessments in routine clinical settings. Traditional laboratory-based three-dimensional (3D) gait analysis, while accurate, is often cost-prohibitive and technically demanding, restricting its use for longitudinal monitoring. This case report addresses the need for an accessible, objective method to track gait recovery in a patient with a complex calcaneal fracture who presented for physiotherapy eight months post-surgery with severe functional limitations, including an antalgic gait, absent heel strike, and an inability to perform daily activities such as prayer prostration.

Methodology
The study employed a single-case, longitudinal observational design involving a 28-year-old female patient. The methodology centered on the use of smartphone-based markerless motion capture using MediaPipe BlazePose to quantify gait kinematics over an 81-day rehabilitation period, with a follow-up at Day 108.

• Data Acquisition: Video-based gait analysis was conducted at four distinct timepoints: Day 1 (baseline), Day 69 (walking reassessment), Day 81 (running assessment), and Day 108 (follow-up). All recordings utilized the same smartphone, camera position, frame rate, and walking distance to minimize measurement variability.
• Kinematic Calculation: Joint angles were derived from MediaPipe landmark coordinates using the arctan2 method. Metrics included mean ankle, knee, and hip angles during walking, as well as pelvic drop, trunk sway, and shoulder tilt during running (derived from posterior-view analysis in normalized lateral-offset units).
• Intervention: The patient underwent a structured, supervised physiotherapy program three times weekly. The protocol progressed from muscle activation and strengthening (Days 1–14) to progressive resistance and proximal stability training (Days 15–56), and finally to dynamic balance, agility, and running retraining (Days 57–81).
• Limitations of Method: The study explicitly notes that the MediaPipe-derived measurements were used to document longitudinal within-patient changes rather than to establish diagnostic validity against a reference standard, as no concurrent laboratory 3D motion capture was performed.

Key Results
The objective data documented substantial functional recovery and kinematic normalization over the course of the intervention:

• Restoration of Heel Strike: By Day 69, the patient achieved a complete restoration of heel strike, a critical functional milestone previously absent.
• Kinematic Improvements:
  • Knee Angle: Improved from a mean of 161.3° (Day 1) to 145.0° (Day 69), indicating increased flexion and a less protective gait pattern.
  • Hip Angle: Decreased from a mean of 158.3° (Day 1) to 139.7° (Day 69).
  • Stability Metrics: By Day 81, during independent running, the patient demonstrated a pelvic drop of 0.003, trunk sway of 0.008, and shoulder tilt of 0.004.
• Functional Outcomes: The patient progressed from a severe antalgic gait with a walking tolerance of less than five minutes to independent running without assistive devices. At the Day 108 follow-up, gait symmetry metrics remained improved and stable, with multi-view analysis confirming consistent heel strike patterns and coordinated lower-limb trajectories.
• Clinical Correlation: These objective improvements correlated with the patient's ability to perform daily prayer prostration without pain and the resolution of functional limitations.

Significance and Claims
The paper positions this work as a proof-of-concept longitudinal observation rather than a definitive establishment of treatment efficacy. The author claims that:

1. Feasibility: Smartphone-based MediaPipe gait analysis is a feasible and clinically informative tool for documenting longitudinal gait changes in rehabilitation settings where laboratory-based systems are unavailable.
2. Delayed Recovery Potential: Substantial functional recovery is possible even when physiotherapy is initiated eight months post-ORIF, challenging the notion that late intervention yields poor outcomes.
3. Objective Monitoring: The study demonstrates that markerless pose estimation can capture meaningful within-patient kinematic changes (such as the restoration of heel strike and joint angle normalization) over time.

The author maintains a modest tone, explicitly stating that the findings cannot be generalized to the wider population due to the single-case nature of the study. They emphasize that the gait symmetry categories and normalized metrics used are derived from the specific video analysis and are not validated normative thresholds. The paper concludes that while the approach shows promise as an accessible adjunct to routine physiotherapy, future prospective studies with larger cohorts and validation against laboratory-based 3D motion capture are necessary to determine clinical equivalence and diagnostic accuracy.