Clinical and Functional Outcome After Lateral Trochlear Lengthening Osteotomy Lateral Trochlear Lengthening Osteotomy

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the functional and clinical outcome of this new lengthening osteotomy of the lateral trochlea in patients with patella instability, trochlear dysplasia Dejour type A or B, short lateral articular trochlea quantified by the lateral condyle index and presence of a lateral trochlear bump.

Detailed Description
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A short lateral articular trochlea leads to failure in stabilizing the patella close to full Extension of the knee. To address this type of pathology, a trochlear lengthening osteotomy was described. To date only case reports describing the clinical outcome of this new osteotomy exist and information on functional outcome regarding muscle strength and electromyography (EMG) data is lacking. The purpose of this study is to evaluate the functional and clinical outcome of this new lengthening osteotomy of the lateral trochlea in patients with patella instability, trochlear dysplasia Dejour type A or B, short lateral articular trochlea quantified by the lateral condyle index and presence of a lateral trochlear bump.

Official Title
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Tro_Le_Tomy - Clinical and Functional Outcome After Lateral Trochlear Lengthening Osteotomy

Conditions
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Patellar Instability

Intervention / Treatment
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* Other: Collection of clinical measurements
* Other: Collection of data for muscle strength
* Other: Collection of EMG Data
* Other: Collection of Clinical Scores
* Other: Collection of Imaging Data - Radiological measurements


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 2 years (as of September 2019) since conducting a lateral trochlear lengthening osteotomy Exclusion Criteria: Inability to provide informed consent Neurological disorders potentially affecting lower extremity muscle strength. Surgery involving the patellofemoral joint prior to the lateral trochlear lengthening osteotomy

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Collection of clinical measurements|Collection of clinical measurements: Active and passive range of motion (ROM) of the knee, hip and ankle Joint bilaterally. Passive patellar translation in 30° of flexion billaterally in quadrants of translation. Patellar apprehension test (Fairbank's Test) and the Moving Patellar Apprehension (MPAT) test for the diagnosis of patellar instability. The Fairbank's Test is performed in 30° of Flexion while the MPAT is performed while flexing the knee from 0° to 90°.|
|Other: Collection of data for muscle strength|Collection of data for muscle strength: Muscle strength will be measured bilaterally using a dynamometer (Biodex System 4 Pro: Biodex Medical Systems, Shirley, NY, USA). For the knee, maximum isokinetic Flexion and extension torques will be collected between full extension and full flexion at a movement speed of 60°/s (3 x 5 repetitions) Maximum joint torques in each movement direction will be recorded for each joint and normalized to body weight|
|Other: Collection of EMG Data|Collection of EMG Data: Surface electrodes will be placed bilaterally on the vastus medialis and lateralis rectus femoris, biceps femoris and semitendinosus muscles following the guidelines of the SENIAM project (Surface ElectroMyoGraphy for the Non-Invasive Assessment of Muscles). Simultaneously with the muscle strength measurements, EMG data will be collected using a 12-channel EMG system (myon AG, Schwarzenberg, Switzerland, sampling rate 2400 Hz).|
|Other: Collection of Clinical Scores|Collection of Clinical Scores: patient's pain, range of motion and ability to perform daily living activities will be assessed using the Kujala Anterior Knee Pain Scale, Lysholm Knee Score, visual analog scale score (VAS) and the Tegner Activity Score|
|Other: Collection of Imaging Data - Radiological measurements|Collection of Imaging Data - Radiological measurements: Xrays and MRIs which were already performed as part of the original diagnostic and follow-up procedures pre- and postoperative will be reviewed and analysed.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| presence of a recurrent patellar dislocation/ radiological reduction of the trochlear bump postoperative by plain radiograph of the knee/ lateral view | presence of a recurrent patellar dislocation postoperative by plain radiograph of the knee/ lateral view: crossing sign: The sign is positive when the trochlear groove lies in same plane as anterior border of lateral condyle. It represents a flattened trochlear groove double contour sign: The sign is positive when the anterior border of lateral condyle lies anterior to anterior border of medial condyle. It represents a convex trochlear groove/hypoplastic medial condyle presence of a lateral trochlear bump prominence the patellar height will be evaluated according to Insall-Salvati method (normal between 0.8 and 1.2) and Caton Deschamps method (normal between 0.6 and 1.3) | at Baseline | 
| presence of a recurrent patellar dislocation/ radiological reduction of the trochlear bump postoperative by Skyline patellar view | The trochlea form will be assessed, the existence of trochlear dysplasia will be confirmed and classified according to Dejour | at Baseline | 
| (Change in) Lateral condyle index assessed by MRI of the knee | Lateral condyle index assessed by MRI of the knee (preoperative (always conducted) and in the cases where they are available postoperative MRIs). The lateral condyle index was designed to measure the lateral trochlea by comparing the anterior cartilaginous trochlea (a) and the posterior aspect (p) [(a:p)× 100]. | at Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Subjective Evaluation of the outcome of the operation | The patients will be asked to subjectively evaluate the outcome of the operation according to the following options: Excellent: Patient is fully recovered and has resumed all activity without restrictions Somewhat Improved: Patient is mostly recovered and has resumed a majority of activities Unchanged: Patient outcome is equivalent to pre-operative complaints Somewhat Worse: Patient is experiencing symptoms worse than pre-operative complaints Significantly Worse: Patient outcome is worse than pre-operative complaints with significantly worse symptoms | at Baseline | 
| Kujala Anterior Knee Pain Scale (AKPS) | The Kujala AKPS is a 13-item screening instrument designed to assess patellofemoral pain in adolescents and young adults, with a variable ordinal response format. For example, a 'Limp' score would be scored as follows: none (5), slight/periodic (3), constant (0). Total scores range from 0 to 100. | at Baseline | 
| Lysholm Knee Score | The Lysholm Knee Score consists of eight items that measure: pain (25 points), instability (25 points), locking (15 points), swelling (10 points), limp (5 points), stair climbing (10 points), squatting (5 points), and need for support (5 points). Every question response has been assigned an arbitrary score on an increasing scale. The total score is the sum of each response to the eight questions, and may range from 0-100. Higher scores indicate a better outcome with fewer symptoms or disability. | at Baseline | 
| Visual analog scale score (VAS) | The visual analogue scale (VAS) is 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. | at Baseline | 
| Tegner activity scale | The Tegner activity scale is a one-item score that graded activity based on work and sports activities on a scale of 0 to 10. Zero represents disability because of knee problems and 10 represents national or international level soccer. | at Baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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lengthening osteotomy of the lateral trochlea, Lateral trochlear lengthening osteotomy, trochlear dysplasia Dejour type A or B, short lateral articular trochlea