NaviFast 6D for Limb Length Measurement During Total Hip Arthroplasty (NaviFast6D)

Orthopedic Miniature Measuring Arm for Assessing Selected Parameters During Total Hip Arthroplasty

This multicenter clinical investigation evaluated the NaviFast 6D orthopedic miniature measuring arm during total hip arthroplasty. NaviFast 6D is an intraoperative measuring device intended to help orthopedic surgeons assess changes in lower limb length and hip offset during surgery.

The study was conducted in adult patients undergoing primary total hip arthroplasty. It included two phases. In the first phase, the device was used to verify functionality, usability, and measurement accuracy without influencing surgical decisions. In the second phase, surgeons could use the intraoperative measurements provided by NaviFast 6D when selecting trial and final implant components.

The main objectives were to compare NaviFast 6D measurements with radiographic measurements of limb length change and to compare postoperative leg length discrepancy between patients treated with NaviFast 6D and a control group treated using conventional clinical assessment. The study also assessed the impact of device use on surgical time and recorded device-related and procedure-related safety events.

Study Overview

• Status: Completed
• Conditions: Hip Osteoarthritis; Total Hip Arthroplasty (THA)
• Intervention / Treatment: Device: NaviFast 6D Measuring Arm; Procedure: Conventional Clinical Assessment During Total Hip Arthroplasty

Detailed Description

This was a multicenter, controlled, open-label, non-randomized clinical investigation of the NaviFast 6D orthopedic miniature measuring arm in patients undergoing primary total hip arthroplasty.

NaviFast 6D is an active, invasive surgical medical device with a measuring function. The device consists of pelvic and femoral fixation elements, an articulated measuring arm with motion sensors, and a microprocessor unit with a display. It is intended for professional use by orthopedic surgeons during total hip arthroplasty to provide intraoperative information on changes in lower limb length and hip offset relative to the pre-implantation state.

During the procedure, fixation elements were attached to the pelvis and femur using cannulated screws. The measuring arm connected the two fixation elements and recorded relative displacement in six degrees of freedom. A baseline measurement was taken before implantation. After preparation of the acetabulum and femur and placement of trial components, the measuring arm was used again to assess the change in limb length and offset. The surgeon could then consider these measurements before final implantation.

The clinical investigation was conducted in two phases. Phase I focused on verification of device functionality, safety, usability, optimization of the measurement procedure, and comparison of NaviFast 6D measurements with reference radiographic measurements. During Phase I, surgical decisions were based on standard clinical assessment rather than on the device measurements. Phase II evaluated use of the final device configuration in clinical practice, with surgeons allowed to use NaviFast 6D measurements when selecting implant components, unless clinical assessment contradicted the measurement.

The primary objective of Phase I was to determine the accuracy of NaviFast 6D measurements of limb length change and hip offset compared with radiographic reference measurements. The primary objective of Phase II was to compare postoperative leg length discrepancy in patients treated with NaviFast 6D with a control group treated using conventional clinical assessment only.

Secondary objectives included assessment of the accuracy of the radiographic reference measurement method using the LLDcalc.com software, estimation of the additional operative time associated with use of NaviFast 6D, and identification and classification of adverse events or device deficiencies associated with use of the measuring arm.

The study population consisted of adult patients undergoing primary total hip arthroplasty. Patients were enrolled at participating clinical centers in Poland. The overall study period covered recruitment, surgical procedures, and postoperative observation from May 9, 2023 to August 30, 2024.

• Study Type: Interventional
• Enrollment (Actual): 84
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Poland
  • Zakopane, Poland
    • University Orthopaedic and Rehabilitation Hospital
  • Greater Poland Voivodeship
    • Kalisz, Greater Poland Voivodeship, Poland
      • Wojewódzki Szpital Zespolony im. L. Perzyny
  • Lublin Voivodeship
    • Lublin, Lublin Voivodeship, Poland
      • Military Clinical Hospital in Lublin
  • Łódź Voivodeship
    • Pabianice, Łódź Voivodeship, Poland
      • Pabianice Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients scheduled for primary total hip arthroplasty.
• Male or female patients.
• Age 20 to 85 years.
• No previous surgical procedures in the affected hip joint.
• Ability and willingness to provide informed consent for participation in the clinical investigation.

Exclusion Criteria:

• Lack of informed consent to participate in the clinical investigation.
• Pregnancy.
• Femoral neck fracture.
• Pertrochanteric femoral fracture.
• Pseudarthrosis of the femoral neck.
• Traumatic or post-traumatic changes of the proximal femur or acetabular region.
• Bone neoplasm.
• Bone infection.
• Advanced osteoporosis.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: NaviFast 6D Measuring Arm; Patients undergoing primary total hip arthroplasty with intraoperative use of the NaviFast 6D orthopedic miniature measuring arm. The device was used to measure changes in lower limb length and hip offset during surgery. In Phase I, measurements were recorded but did not guide surgical decisions. In Phase II, surgeons could use NaviFast 6D measurements when selecting trial and final implant components.	Device: NaviFast 6D Measuring Arm; NaviFast 6D is an orthopedic miniature measuring arm used intraoperatively during total hip arthroplasty to measure changes in lower limb length and hip offset relative to the pre-implantation state. The device includes pelvic and femoral fixation elements, an articulated measuring arm with motion sensors, and a microprocessor unit with a display.
Active Comparator: Conventional Clinical Assessment; Patients undergoing primary total hip arthroplasty using conventional intraoperative clinical assessment only, without use of the NaviFast 6D measuring arm. This group served as the control group for comparison of postoperative leg length discrepancy.	Procedure: Conventional Clinical Assessment During Total Hip Arthroplasty; Standard intraoperative clinical assessment used during primary total hip arthroplasty without use of the NaviFast 6D measuring arm. Assessment of limb length and hip biomechanics was based on the surgeon's conventional visual, palpatory, and clinical judgment during the procedure.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Accuracy of NaviFast 6D Measurement of Lower Limb Length Change	Accuracy of intraoperative lower limb length change measurement performed with the NaviFast 6D measuring arm, assessed by comparing NaviFast 6D measurements with reference radiographic measurements obtained from preoperative and postoperative pelvic radiographs analyzed using LLDcalc.com software. The endpoint was expressed as the root mean square difference between NaviFast 6D and radiographic measurements in millimeters.	Preoperative pelvic radiograph, an average of 1 day before surgery; intraoperative NaviFast 6D measurement during surgery; and postoperative pelvic radiograph, an average of 1 day after surgery
Postoperative Leg Length Discrepancy Compared With Control Group	Postoperative leg length discrepancy was compared between patients undergoing total hip arthroplasty with intraoperative use of NaviFast 6D and patients undergoing total hip arthroplasty using conventional intraoperative clinical assessment only. Leg length discrepancy was assessed on postoperative radiographs and expressed in millimeters.	At postoperative pelvic radiographic assessment, an average of 1 day after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Accuracy of Radiographic Reference Measurement Using LLDcalc.com	Accuracy of the radiographic reference method for assessing leg length discrepancy and hip offset was evaluated using LLDcalc.com software. The analysis assessed the repeatability of measurements performed on radiographs obtained in the same clinical state and expressed results as root mean square differences in millimeters.	At radiographic image analysis of paired preoperative or paired postoperative pelvic radiographs obtained in the same clinical state within approximately 1 to 3 months
Additional Operative Time Associated With NaviFast 6D Use	Additional operative time associated with use of the NaviFast 6D measuring arm was estimated based on the time required for device fixation, intraoperative measurement procedures, and potential implant component adjustment based on device readings.	During the surgical procedure
Adverse Events and Device Deficiencies Associated With NaviFast 6D	Adverse events, serious adverse events, device deficiencies, and corrective actions associated with intraoperative use of the NaviFast 6D measuring arm were recorded and classified throughout the clinical investigation.	From the start of the surgical procedure through postoperative Day 2

Collaborators and Investigators

• Sponsor: Lodz University of Technology
• Investigators: Principal Investigator: Ireneusz Urbaniak, MD, PhD, Wojewódzki Szpital Zespolony im. L. Perzyny

Study record dates

Study Major Dates

• Study Start (Actual): May 9, 2023
• Primary Completion (Actual): August 30, 2024
• Study Completion (Actual): August 30, 2024

Study Registration Dates

• First Submitted: May 5, 2026
• First Submitted That Met QC Criteria: May 14, 2026
• First Posted (Actual): May 19, 2026

Study Record Updates

• Last Update Posted (Actual): May 19, 2026
• Last Update Submitted That Met QC Criteria: May 14, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Total Hip Arthroplasty; Leg Length Discrepancy; NaviFast 6D; Intraoperative Measurement; Radiographic Measurement; Hip Offset
• Additional Relevant MeSH Terms: Bone Diseases; Musculoskeletal Diseases; Pathological Conditions, Anatomical; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Bone Diseases, Developmental; Pathological Conditions, Signs and Symptoms; Osteoarthritis, Hip; Leg Length Inequality
• Other Study ID Numbers: PBK 1.3; POIR.01.01.01-00-0290/21 (Other Grant/Funding Number: National Centre for Research and Development)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared because the dataset contains sensitive clinical and radiographic information, and no formal individual participant data sharing plan or participant consent for such sharing was defined in the study protocol. Aggregate results will be reported in publications.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No