Comparison of Dynamic and Static Medial Patellofemoral Ligament Operation Technique for Recurrent Patellar Dislocation

Study Overview
=================
Brief Summary
-----------------
This study is to evaluate whether the dynamic Medial Patellofemoral Ligament (MPFL) reconstruction as described by Becher is a successful operation technique to prevent patella instability and restore quality of life. It is to assess and compare clinical and functional outcomes of dynamic and static medial patellofemoral ligament reconstruction

Detailed Description
-----------------
The recurrent dislocation rate of conservatively treated chronic patellar instability is high, therefore, it is recommended to manage it surgically. A frequently used surgical technique is static medial patellofemoral ligament (MPFL) reconstruction (e.g. Schöttle-technique). A novel dynamic surgical technique according to Becher was developed, addressing the most common complications occurring in static reconstruction, which are malpositioning and overtensioning of the graft. This study is to assess and compare clinical and functional outcomes of dynamic and static medial patellofemoral ligament reconstruction.

Official Title
-----------------
DynMPFL - Comparison of Dynamic and Static Medial Patellofemoral Ligament Operation Technique for Recurrent Patellar Dislocation

Conditions
-----------------
Patellar Instability

Intervention / Treatment
-----------------
* Procedure: Static reconstruction technique according to Schöttle
* Procedure: Dynamic reconstruction technique according to Becher


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients treated with isolated dynamic (operation procedure according to Becher et al.using the gracilis tendon) or static MPFL plastic (operation procedure according to Schöttle et al. using the gracilis tendon). MPFL reconstruction will be performed in patients with preceding patella dislocation with: 1) a Patella-Instability-Severity (PIS) score ≤ 3 with concomitant flake fracture or 2) a PIS score ≥ 4 with clinical asymptomatic trochlea dysplasia (patella stability between 30°-60° knee flexion) without other clinically relevant static risk factors. Closed growth plates Exclusion Criteria: Combined procedures with trochleoplasty (high grade trochlea dysplasia, type Dejour C,D with clinical instability between 30° and 60° of knee flexion) combined procedures with cartilage transplantation High grade patellofemoral arthritis (Kellgren Lawrence score ≥3) combined procedures with femoral or tibial osteotomy Clinically eminent valgus axis (>15° valgus) Femoral internal rotation >20°, tibial external rotation >40° Instability of the cruciate or collateral ligaments Known significant musculoskeletal disease Cognitive impairment

Ages Eligible for Study
-----------------
Minimum Age: 14 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Multicentre prospective longitudinal randomized clinical trial
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Static reconstruction technique according to Schöttle<br>Static reconstruction technique according to Schöttle | Procedure: Static reconstruction technique according to Schöttle<br>* In static MPFL reconstruction, a graft (harvested autologous gracilis tendon or allogen transplant) is attached to the femoral and patellar bones using tunnels, screws, and/or anchors.<br>|
| Active Comparator: Dynamic reconstruction technique according to Becher<br>Dynamic reconstruction technique according to Becher | Procedure: Dynamic reconstruction technique according to Becher<br>* Dynamic MPFL procedure by detaching and reinserting only the distal part of a hamstring muscle to the patella and leaving the proximal tendon attached to its muscle. This way the patella position can be adjusted dynamically by hamstring contraction.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Kujala score | Patient reported knee function and anterior knee pain as assessed with the Kujala score at preoperative screening, at the hospitalization time and four postoperative follow ups . The Kujala scale consists of 13 questions covering a range of physical symptoms and limitations that are presented in a multiple choice answer format, with a different point value assigned to each answer. The maximum score is 100, with higher scores indicating better function. | up to 24 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of recurrent patella dislocation | Surgical outcome: recurrent patella dislocation. | From MPFL surgery to occurring recurrent patella dislocation (up to 24 months) | 
| Number of revision surgery | Surgical outcome: revision surgery. | From MPFL surgery to occurring revision surgery (up to 24 months) | 
| Number of complications (other than revision surgery, e.g. infection, wound healing disorder) | Surgical outcome: complications (other than revision surgery, e.g. infection, wound healing disorder). | From MPFL surgery to occurring complication (up to 24 months) | 
| Change in Banff-II-score from preoperative screening, at the hospitalization time and four postoperative follow ups | The Banff Patella Instability Instrument (BPII) is a disease-specific health-related quality of life score. It is a patient-reported, disease-specific QOL score that consists of 23 questions across five domains covering symptoms/physical complains, work-related concerns, recreational activity and sport participation/competition, lifestyle, and social/emotional. Patients mark their answers on a visual analogue scale measuring 100 mm in length. Each item is equally weighted with the final score calculated as an average of the scores from all answered items. A higher score reflects a higher QOL. | up to 24 months | 
| Change in International Knee Documentation Committee (IKDC)-2000 from preoperative screening, at the hospitalization time and four postoperative follow ups | The IKDC includes 18 questions covering three domains: symptoms, physical activity, and function. The items are answered on Likert scales of varying values. IKDC scores are calculated by dividing the total score by the highest possible score for the items answered, and multiplying by 100, with higher scores indicating better function. | up to 24 months | 
| Change in EQ-5D-5L from preoperative screening, at the hospitalization time and four postoperative follow ups EQ-5D- EQ-5D-5L | The EQ-5D descriptive system comprises five dimensions: mobility, self-care, usual activities, pain and discomfort, and anxiety and depression. The five levels in each dimension are worded as (1) 'not /no problems', (2) 'slight problems', (3) 'moderate problems', (4) 'severe problems', and (5) 'unable to' (mobility, self-care, usual activities), 'extreme' (pain/depression), or 'extremely' (anxiety/depression). | up to 24 months | 
| Change in pain level using the numeric rating scale from preoperative screening, at the hospitalization time and four postoperative follow ups | It is usually presented as a 100-mm horizontal line on which the patient's pain intensity is represented by a point between the extremes of no pain at all and worst pain imaginable. | up to 24 months | 
| Operation time | Operation time | During MPFL surgery (up to 1 day) | 
| Hospitalization time | Length of hospital stay Length of hospital stay | During hospitalization (up to 1 month) | 
| Change in gait asymmetry | Instrumented gait analysis (by EMG) on a treadmill with an embedded plantar pressure plate and on an overground walkway with two embedded force plates. | Preoperatively and 1 year postoperative | 
| Change in isokinetic muscle strength | Muscle strength will be measured bilaterally using a dynamometer. | Preoperatively and 1 year postoperative | 
| Change in timing of muscle activity | Timing of the gracilis muscle will be assessed as on- and offset relative to the gait cycle. Gracilis onset will be determined as the time when the processed EMG signal exceeded a threshold of three standard deviations above a baseline mean and as offset, when the processed EMG signal falls below a threshold of three standard deviations above a baseline mean. | Preoperatively and 1 year postoperative | 
| Change in single legged drop test | Standing erect upon only the tested leg with the foot in neutral position, participants will step off a 30 cm high platform placed 11 cm from the edge of the force-plate. Participants will be instructed to land in the centre of the force-plate on the tested leg only. | Preoperatively and 1 year postoperative | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
patellofemoral ligament reconstruction, chronic patellar instability, static medial patellofemoral ligament (MPFL) reconstruction, static reconstruction technique according to Schöttle, dynamic medial patellofemoral ligament (MPFL) reconstruction, patella dislocation, Patella-Instability-Severity (PIS) score, dynamic reconstruction technique according to Becher