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NCT Number: NCT06981039

Comparison of Patella Plating Versus Tension Band Wiring for the Treatment of Unstable Patellar Fractures

This study aims to compare the efficacy and safety of patella anatomical locking plate fixation versus tension band wiring in the treatment of patellar fractures.

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Key information

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Queen Mary Hospital, The University of Hong Kong

Hong Kong

Location status: Recruiting

Location contact

Christian FANG

CONTACT

[email protected]

+852 22554581

Christian Fang

PRINCIPAL_INVESTIGATOR

About this study

Patellar fractures are a common injury that can cause significant pain and disability. Conventional treatment options frequently include tension band wiring (TBW) with or without axial K-Wires or through cannulated screws. However, tension band wiring does have its issues, including implant prominence and frequent reoperation rates, especially for comminuted patella fractures.

More recently, plate fixation has become increasingly more prevalent in the past decade. Initially, this began with small fragment or mini-fragment plates; which progressed to mesh locking plates and now, anatomical locking patella plates. Biomechanical studies have shown greater loads to failure, less fracture gapping or fracture displacement with locking plate fixation compared to TBW. Its low profile construct and round edges may be more tolerable to patients and less prominent than TBW. Furthermore, another possible advantage of plate fixation is the avoidance of quadricep and patellar tendon insertion scarring, as they do not need to be dissected or passed through for fixation as in TBW. This is the first randomized controlled trial comparing anatomical locking plate fixation and conventional tension band wiring for patella fractures to be performed. This study aims to compare the efficacy and safety of these two methods in the treatment of patellar fractures.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Aged 18 years or older
  • Diagnosed with an isolated closed injury, displaced, unstable fracture with displacement >2mm (AO/OTA Classification 34-B and C with surgical indication)
  • Able to give consent

Exclusion criteria

  • History of previous knee surgery
  • Poly trauma,
  • Ongoing malignancy
  • Pre-existing severe knee osteoarthritis (>KL stage 4)
  • Stroke
  • Other neurological conditions/injuries to the lower limb
  • Unfit for surgical anaesthesia
  • Non-ambulatory
  • Unable to consent or follow commands

Treatment and study plan

Patella Anatomical Locking Plate

Device

Patients in the patella anatomical locking plate group will undergo internal fixation with an anterior locking plate and screw construct using the 2.7mm variable angle (VA) locking patella plating system (DePuy Synthes, Zuchwil, Switzerland)

Tension Band Wiring

Device

Patients in the tension band wiring group will undergo open anatomical reduction and internal fixation with a tension band wire construct.

Primary outcomes

  1. Region specific patient reported functional outcome scores - Knee Injury and Osteoarthritis Outcome Score (KOOS)

    Time frame: At post-op 2 weeks, 6 weeks , 12 weeks and 6 months and 12 months

    The KOOS's five patient-relevant dimensions are scored separately: Pain (nine items); Symptoms (seven items); ADL Function (17 items); Sport and Recreation Function (five items); Quality of Life (four items). A Likert scale is used, and all items have five possible answer options scored from 0 (No problems) to 4 (Extreme problems), and each of the five scores is calculated as the sum of the items included. Scores are transformed to a 0-100 scale, with zero representing extreme knee problems and 100 representing no knee problems as common in orthopaedic scales and generic measures. Scores between 0 and 100 represent the percentage of total possible score achieved.

  2. Tegner Lysholm Knee Score

    Time frame: At post-op 2 weeks, 6 weeks , 12 weeks and 6 months and 12 months

    The Lysholm Knee Score calculates and grades an overall score from 0 to 100 based on 8 domains: squatting, locking, pain, stair climbing, support, instability, and edema. Scores between 95 and 100 are regarded as exceptional, 84 and 94 as acceptable, 65 to 83 as fair, and less than 65 as poor.

  3. Tegner Activity Scale

    Time frame: At post-op 2 weeks, 6 weeks , 12 weeks and 6 months and 12 months

    The Tegner Activity Scale is a one-item questionnaire that is scored on an 11-item scale (0 to 10) based on the patient's reported level of activity/work. A level of 0 represents maximum disability while a level of 10 represents elite sports athletes. Patients are asked to choose the highest level of activity they partake in at that moment.

Secondary outcomes

  1. Radiographic outcomes

    Time frame: At post-op 2 weeks, 6 weeks , 12 weeks and 6 months and 12 months

    Subjects' X-rays will be assessed for fracture healing progress.

  2. Incidence of Complications

    Time frame: At post-op 2 weeks, 6 weeks , 12 weeks and 6 months and 12 months

    Complications such as fracture site infection, implant failure, and re-operation will be assessed and recorded

  3. Subjective Implant Impingement Questionnaire

    Time frame: At post-op 2 weeks, 6 weeks , 12 weeks and 6 months and 12 months

    The questionnaire consists of 11 questions assessing the level of implant impingement reported by the patient, with a final score ranging from 0 (no impingement) to 20 (consistent impingement).

Study contacts

Contact information is provided by the study sponsor or research team.

Christian FANG

CONTACT

[email protected]

+852 22554581

Sponsors and collaborators

Lead sponsor

The University of Hong Kong

Other

Registry information

Official study title

The WASP Trial (Wiring Versus Anterior Star Plate): Comparison of Patella Plating Versus Tension Band Wiring for the Treatment of Unstable Patellar Fractures: A Randomized Controlled Trial

Acronym: WASP

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
May 20, 2025
Registry last updated
May 20, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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