Predicting Outcome of Total Knee Replacement Surgery in Patients With Knee Osteoarthritis

Osteoarthritis, Knee Clinical Trial

Official title:

Predicting Outcome of Total Knee Replacement Surgery in Patients With Knee Osteoarthritis: a Prospective Study on the Role of Altered Central Pain Processing and Structural, Functional, Metabolic, Inflammatory and Psychological Factors

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT05380648
• Other study ID #: 13/47/472
• Status: Completed
• Start date: March 8, 2018
• Est. completion date: July 14, 2023

Study information

• Verified date: December 2023
• Source: Universiteit Antwerpen
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational [Patient Registry]

Clinical Trial Summary

Osteoarthritis (OA) is the main cause of pain and disability in elderly. For knee OA, a total knee replacement (TKR) is an effective surgical treatment, and the majority of patients report substantial pain relief and functional improvement following surgery. However, 20-40% of patients undergoing TKR are dissatisfied with postsurgical outcome. Even after revision, some patients keep complaining of persisting pain.

In this study, the investigators will examine putative prognostic factors on the basis of the biopsychosocial model. Besides several psychological factors (measured with questionnaires), the investigators will assess structural impairments (such as radiographic severity of OA), functional impairments (muscle weakness and proprioceptive deficits), anesthetic procedures, immediate postoperative pain management, metabolic factors (body composition and hemoglobin A1c), inflammatory factors (C-Reactive Protein) and the investigators also will examine the role of altered central pain processing (CPP) (primary and secondary mechanical hyperalgesia, mechanical temporal summation, thermal primary and secondary hyperalgesia, endogenous pain modulation).

With a longitudinal study design, this study will explore which factors are predictive of poor outcome in knee OA patients after TKR. Moreover, the interrelationship between CPP, structural, functional, metabolic, inflammatory and psychological factors, and the clinical expression of knee OA (pain, symptoms, physical performance and quality of life) will be investigated.

Further research on the role of the aforementioned putative prognostic factors on postsurgical outcome could contribute to better management of these patients, since these factors may be particularly important for patient-tailored treatment.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 223
• Est. completion date: July 14, 2023
• Est. primary completion date: July 14, 2023
• Accepts healthy volunteers: No
• Gender: All
• Age group: 40 Years and older

Eligibility

Inclusion Criteria:

• Knee OA patients >40 years awaiting TKR surgery. Both men and women of all ethnical backgrounds are included.

Exclusion Criteria:

• Patients with diagnosis of neurological/ systemic diseases, possibly impacting pain

• Patients who are not capable of understanding and speaking Dutch

• Revision surgery

Related Conditions & MeSH terms

• Arthroplasty, Replacement, Knee
• Osteoarthritis
• Osteoarthritis, Knee

Intervention

Procedure:
• Total knee arthroplasty
Total knee arthroplasty surgery will be performed by different orthopedist.

Locations

Country	Name	City	State
Belgium	University of Antwerp	Antwerp

Sponsors (1)

Lead Sponsor	Collaborator
Universiteit Antwerpen

Country where clinical trial is conducted

Belgium, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Pain intensity	The subscale 'Pain' of the Knee injury and Osteoarthritis Outcome Score (KOOS) will be used as primary outcome measure. Minimum score is 0, maximum score is 36. Scores are always transformed to a 0-100 scale. The higher the score, the higher the pain intensity.	Change from baseline pain intensity at 3 months postoperative
Primary	Pain intensity	The subscale 'Pain' of the Knee injury and Osteoarthritis Outcome Score (KOOS) will be used as primary outcome measure. Minimum score is 0, maximum score is 36. Scores are always transformed to a 0-100 scale. The higher the score, the higher the pain intensity.	Change from baseline pain intensity at 1 year postoperative
Primary	Pain intensity	The subscale 'Pain' of the Knee injury and Osteoarthritis Outcome Score (KOOS) will be used as primary outcome measure. Minimum score is 0, maximum score is 36. Scores are always transformed to a 0-100 scale. The higher the score, the higher the pain intensity.	Change from 3 months postoperative at 1 year postoperative
Primary	Pain intensity	The subscale 'Pain' of the Knee injury and Osteoarthritis Outcome Score (KOOS) will be used as primary outcome measure. Minimum score is 0, maximum score is 36. Scores are always transformed to a 0-100 scale. The higher the score, the higher the pain intensity.	Baseline (preoperative)
Primary	Pain intensity	The subscale 'Pain' of the Knee injury and Osteoarthritis Outcome Score (KOOS) will be used as primary outcome measure. Minimum score is 0, maximum score is 36. Scores are always transformed to a 0-100 scale. The higher the score, the higher the pain intensity.	3 months postoperative
Primary	Pain intensity	The subscale 'Pain' of the Knee injury and Osteoarthritis Outcome Score (KOOS) will be used as primary outcome measure. Minimum score is 0, maximum score is 36. Scores are always transformed to a 0-100 scale. The higher the score, the higher the pain intensity.	1 year postoperative
Secondary	Central pain processing: mechanical local and widespread hyperalgesia allodynia	Measured with quantitative sensory testing (QST): mechanical pain pressure threshold measured with digital algometer at the medial knee joint line, lateral knee joint line and m. Tibialis anterior of affected leg, m. extensor carpi radialis of non-dominant arm and forehead.	Change from baseline (preoperative) to 3 months postoperative
Secondary	Central pain processing: mechanical local and widespread hyperalgesia allodynia	Measured with quantitative sensory testing (QST): mechanical pain pressure threshold measured with digital algometer at the medial knee joint line, lateral knee joint line and m. Tibialis anterior of affected leg, m. extensor carpi radialis of non-dominant arm and forehead.	Change from baseline (preoperative) to 1 year postoperative
Secondary	Central pain processing: mechanical local and widespread hyperalgesia allodynia	Measured with quantitative sensory testing (QST): mechanical pain pressure threshold measured with digital algometer at the medial knee joint line, lateral knee joint line and m. Tibialis anterior of affected leg, m. extensor carpi radialis of non-dominant arm and forehead.	Change from 3 months postoperative to 1 year postoperative
Secondary	Central pain processing: mechanical local and widespread hyperalgesia allodynia	Measured with quantitative sensory testing (QST): mechanical pain pressure threshold measured with digital algometer at the medial knee joint line, lateral knee joint line and m. Tibialis anterior of affected leg, m. extensor carpi radialis of non-dominant arm and forehead.	Baseline (preoperative)
Secondary	Central pain processing: mechanical local and widespread hyperalgesia allodynia	Measured with quantitative sensory testing (QST): mechanical pain pressure threshold measured with digital algometer at the medial knee joint line, lateral knee joint line and m. Tibialis anterior of affected leg, m. extensor carpi radialis of non-dominant arm and forehead.	3 months postoperative
Secondary	Central pain processing: mechanical local and widespread hyperalgesia allodynia	Measured with quantitative sensory testing (QST): mechanical pain pressure threshold measured with digital algometer at the medial knee joint line, lateral knee joint line and m. Tibialis anterior of affected leg, m. extensor carpi radialis of non-dominant arm and forehead.	1 year postoperative
Secondary	Central pain processing: bottom-up sensitization	Measured with quantitative sensory testing (QST): temporal summation measured with a 60g Von Frey monofilament at the medial knee and lateral knee of affected leg, dorsal wrist of affected side	Change from baseline (preoperative) to 3 months postoperative
Secondary	Central pain processing: bottom-up sensitization	Measured with quantitative sensory testing (QST): temporal summation measured with a 60g Von Frey monofilament at the medial knee and lateral knee of affected leg, dorsal wrist of affected side	Change from baseline (preoperative) to 1 year postoperative
Secondary	Central pain processing: bottom-up sensitization	Measured with quantitative sensory testing (QST): temporal summation measured with a 60g Von Frey monofilament at the medial knee and lateral knee of affected leg, dorsal wrist of affected side	Change from 3 months postoperative to 1 year postoperative
Secondary	Central pain processing: bottom-up sensitization	Measured with quantitative sensory testing (QST): temporal summation measured with a 60g Von Frey monofilament at the medial knee and lateral knee of affected leg, dorsal wrist of affected side	Baseline (preoperative)
Secondary	Central pain processing: bottom-up sensitization	Measured with quantitative sensory testing (QST): temporal summation measured with a 60g Von Frey monofilament at the medial knee and lateral knee of affected leg, dorsal wrist of affected side	3 months postoperative
Secondary	Central pain processing: bottom-up sensitization	Measured with quantitative sensory testing (QST): temporal summation measured with a 60g Von Frey monofilament at the medial knee and lateral knee of affected leg, dorsal wrist of affected side	1 year postoperative
Secondary	Central pain processing: Thermal hyperalgesia	Measured with quantitative sensory testing (QST): thermal pain sensitivity measured with thermal rollers (Rolltemp II somedic senselab) at the medial knee and lateral knee of affected leg and m. extensor carpi radialis of non-dominant arm.	Change from baseline (preoperative) to 3 months postoperative
Secondary	Central pain processing: Thermal hyperalgesia	Measured with quantitative sensory testing (QST): thermal pain sensitivity measured with thermal rollers (Rolltemp II somedic senselab) at the medial knee and lateral knee of affected leg and m. extensor carpi radialis of non-dominant arm.	Change from baseline (preoperative) to 1 year postoperative
Secondary	Central pain processing: Thermal hyperalgesia	Measured with quantitative sensory testing (QST): thermal pain sensitivity measured with thermal rollers (Rolltemp II somedic senselab) at the medial knee and lateral knee of affected leg and m. extensor carpi radialis of non-dominant arm.	Change from 3 months postoperative to 1 year postoperative
Secondary	Central pain processing: Thermal hyperalgesia	Measured with quantitative sensory testing (QST): thermal pain sensitivity measured with thermal rollers (Rolltemp II somedic senselab) at the medial knee and lateral knee of affected leg and m. extensor carpi radialis of non-dominant arm.	Baseline (preoperative)
Secondary	Central pain processing: Thermal hyperalgesia	Measured with quantitative sensory testing (QST): thermal pain sensitivity measured with thermal rollers (Rolltemp II somedic senselab) at the medial knee and lateral knee of affected leg and m. extensor carpi radialis of non-dominant arm.	3 months postoperative
Secondary	Central pain processing: Thermal hyperalgesia	Measured with quantitative sensory testing (QST): thermal pain sensitivity measured with thermal rollers (Rolltemp II somedic senselab) at the medial knee and lateral knee of affected leg and m. extensor carpi radialis of non-dominant arm.	1 year postoperative
Secondary	Central pain processing: dysfunctional endogenous pain analgesia	Measured with quantitative sensory testing (QST): conditioned pain modulation measured Medoc at both wrists	Change from baseline (preoperative) to 3 months postoperative
Secondary	Central pain processing: dysfunctional endogenous pain analgesia	Measured with quantitative sensory testing (QST): conditioned pain modulation measured Medoc at both wrists	Change from baseline (preoperative) to 1 year postoperative
Secondary	Central pain processing: dysfunctional endogenous pain analgesia	Measured with quantitative sensory testing (QST): conditioned pain modulation measured Medoc at both wrists	Change from 3 months postoperative to 1 year postoperative
Secondary	Central pain processing: dysfunctional endogenous pain analgesia	Measured with quantitative sensory testing (QST): conditioned pain modulation measured Medoc at both wrists	Baseline (preoperative)
Secondary	Central pain processing: dysfunctional endogenous pain analgesia	Measured with quantitative sensory testing (QST): conditioned pain modulation measured Medoc at both wrists	3 months postoperative
Secondary	Central pain processing: dysfunctional endogenous pain analgesia	Measured with quantitative sensory testing (QST): conditioned pain modulation measured Medoc at both wrists	1 year postoperative
Secondary	Central pain processing: somatic and emotional symptoms	Questionnaire: the Central sensitization Inventory (CSI). Minimum score is 0, maximum score is 100. The higher the score, the higher the chance for the presence of central sensitization.	Change from baseline (preoperative) to 3 months postoperative
Secondary	Central pain processing: somatic and emotional symptoms	Questionnaire: the Central sensitization Inventory (CSI). Minimum score is 0, maximum score is 100. The higher the score, the higher the chance for the presence of central sensitization.	Change from baseline (preoperative) to 1 year postoperative
Secondary	Central pain processing: somatic and emotional symptoms	Questionnaire: the Central sensitization Inventory (CSI). Minimum score is 0, maximum score is 100. The higher the score, the higher the chance for the presence of central sensitization.	Change from 3 months postoperative to 1 year postoperative
Secondary	Central pain processing: somatic and emotional symptoms	Questionnaire: the Central sensitization Inventory (CSI). Minimum score is 0, maximum score is 100. The higher the score, the higher the chance for the presence of central sensitization.	Baseline (preoperative)
Secondary	Central pain processing: somatic and emotional symptoms	Questionnaire: the Central sensitization Inventory (CSI). Minimum score is 0, maximum score is 100. The higher the score, the higher the chance for the presence of central sensitization.	3 months postoperative
Secondary	Central pain processing: somatic and emotional symptoms	Questionnaire: the Central sensitization Inventory (CSI). Minimum score is 0, maximum score is 100. The higher the score, the higher the chance for the presence of central sensitization.	1 year postoperative
Secondary	Central pain processing: areas of pain	Body chart: Expanded distribution of Pain (EDP). The more pain locations, the more chance for the presence of central sensitization	Change from baseline (preoperative) to 3 months postoperative
Secondary	Central pain processing: areas of pain	Body chart: Expanded distribution of Pain (EDP). The more pain locations, the more chance for the presence of central sensitization	Change from baseline (preoperative) to 1 year postoperative
Secondary	Central pain processing: areas of pain	Body chart: Expanded distribution of Pain (EDP). The more pain locations, the more chance for the presence of central sensitization	Change from 3 months postoperative to 1 year postoperative
Secondary	Central pain processing: areas of pain	Body chart: Expanded distribution of Pain (EDP). The more pain locations, the more chance for the presence of central sensitization	Baseline (preoperative)
Secondary	Central pain processing: areas of pain	Body chart: Expanded distribution of Pain (EDP). The more pain locations, the more chance for the presence of central sensitization	3 months postoperative
Secondary	Central pain processing: areas of pain	Body chart: Expanded distribution of Pain (EDP). The more pain locations, the more chance for the presence of central sensitization	1 year postoperative
Secondary	Psychosocial factors: pain catastrophizing	Measured with Pain Catastrophizing Scale (PCS). Minimum score is 0, maximum score is 52. The higher the score, the higher the pain catastrophizing.	Change from baseline (preoperative) to 3 months postoperative
Secondary	Psychosocial factors: pain catastrophizing	Measured with Pain Catastrophizing Scale (PCS). Minimum score is 0, maximum score is 52. The higher the score, the higher the pain catastrophizing.	Change from baseline (preoperative) to 1 year postoperative
Secondary	Psychosocial factors: pain catastrophizing	Measured with Pain Catastrophizing Scale (PCS). Minimum score is 0, maximum score is 52. The higher the score, the higher the pain catastrophizing.	Change from 3 months postoperative to 1 year postoperative
Secondary	Psychosocial factors: pain catastrophizing	Measured with Pain Catastrophizing Scale (PCS). Minimum score is 0, maximum score is 52. The higher the score, the higher the pain catastrophizing.	Baseline (preoperative)
Secondary	Psychosocial factors: pain catastrophizing	Measured with Pain Catastrophizing Scale (PCS). Minimum score is 0, maximum score is 52. The higher the score, the higher the pain catastrophizing.	3 months postoperative
Secondary	Psychosocial factors: pain catastrophizing	Measured with Pain Catastrophizing Scale (PCS). Minimum score is 0, maximum score is 52. The higher the score, the higher the pain catastrophizing.	1 year postoperative
Secondary	Psychosocial factors: illness perceptions	Illness perception questionnaire-revised (IPQ-R); Identity dimension: yes = 1; no = 0 min score= 0, max score= 18; Other dimensions: min score= 38, max score= 190 strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5; Causal dimension: strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5 min score= 18, max score= 90; High scores on the identity, timeline, consequences, and cyclical dimensions represent strongly held beliefs about the number of symptoms attributed to the illness, the chronicity of the condition, the negative consequences of the illness, and the cyclical nature of the condition.; High scores on the personal control, treatment control and coherence dimensions, represent positive beliefs about the controllability of the illness and a personal understanding of the condition.	Change from baseline (preoperative) to 3 months postoperative
Secondary	Psychosocial factors: illness perceptions	Illness perception questionnaire-revised (IPQ-R); Identity dimension: yes = 1; no = 0 min score= 0, max score= 18; Other dimensions: min score= 38, max score= 190 strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5; Causal dimension: strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5 min score= 18, max score= 90; High scores on the identity, timeline, consequences, and cyclical dimensions represent strongly held beliefs about the number of symptoms attributed to the illness, the chronicity of the condition, the negative consequences of the illness, and the cyclical nature of the condition.; High scores on the personal control, treatment control and coherence dimensions, represent positive beliefs about the controllability of the illness and a personal understanding of the condition.	Change from baseline (preoperative) to 1 year postoperative
Secondary	Psychosocial factors: illness perceptions	Illness perception questionnaire-revised (IPQ-R); Identity dimension: yes = 1; no = 0 min score= 0, max score= 18; Other dimensions: min score= 38, max score= 190 strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5; Causal dimension: strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5 min score= 18, max score= 90; High scores on the identity, timeline, consequences, and cyclical dimensions represent strongly held beliefs about the number of symptoms attributed to the illness, the chronicity of the condition, the negative consequences of the illness, and the cyclical nature of the condition.; High scores on the personal control, treatment control and coherence dimensions, represent positive beliefs about the controllability of the illness and a personal understanding of the condition.	Change from 3 months postoperative to 1 year postoperative
Secondary	Psychosocial factors: illness perceptions	Illness perception questionnaire-revised (IPQ-R); Identity dimension: yes = 1; no = 0 min score= 0, max score= 18; Other dimensions: min score= 38, max score= 190 strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5; Causal dimension: strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5 min score= 18, max score= 90; High scores on the identity, timeline, consequences, and cyclical dimensions represent strongly held beliefs about the number of symptoms attributed to the illness, the chronicity of the condition, the negative consequences of the illness, and the cyclical nature of the condition.; High scores on the personal control, treatment control and coherence dimensions, represent positive beliefs about the controllability of the illness and a personal understanding of the condition.	Baseline (preoperative)
Secondary	Psychosocial factors: illness perceptions	Illness perception questionnaire-revised (IPQ-R); Identity dimension: yes = 1; no = 0 min score= 0, max score= 18; Other dimensions: min score= 38, max score= 190 strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5; Causal dimension: strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5 min score= 18, max score= 90; High scores on the identity, timeline, consequences, and cyclical dimensions represent strongly held beliefs about the number of symptoms attributed to the illness, the chronicity of the condition, the negative consequences of the illness, and the cyclical nature of the condition.; High scores on the personal control, treatment control and coherence dimensions, represent positive beliefs about the controllability of the illness and a personal understanding of the condition.	3 months postoperative
Secondary	Psychosocial factors: illness perceptions	Illness perception questionnaire-revised (IPQ-R); Identity dimension: yes = 1; no = 0 min score= 0, max score= 18; Other dimensions: min score= 38, max score= 190 strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5; Causal dimension: strongly disagree =1, disagree =2, neither agree or disagree = 3, agree = 4, strongly agree = 5 min score= 18, max score= 90; High scores on the identity, timeline, consequences, and cyclical dimensions represent strongly held beliefs about the number of symptoms attributed to the illness, the chronicity of the condition, the negative consequences of the illness, and the cyclical nature of the condition.; High scores on the personal control, treatment control and coherence dimensions, represent positive beliefs about the controllability of the illness and a personal understanding of the condition.	1 year postoperative
Secondary	Psychosocial factors: anxiety	Measured with Hospital Anxiety and Depression Scale (HADS), subscale anxiety. Minimum score is 0, maximum score is 21. The higher the score, the higher the anxiety.	Change from baseline (preoperative) to 3 months postoperative
Secondary	Psychosocial factors: anxiety	Measured with Hospital Anxiety and Depression Scale (HADS), subscale anxiety. Minimum score is 0, maximum score is 21. The higher the score, the higher the anxiety.	Change from baseline (preoperative) to 1 year postoperative
Secondary	Psychosocial factors: anxiety	Measured with Hospital Anxiety and Depression Scale (HADS), subscale anxiety. Minimum score is 0, maximum score is 21. The higher the score, the higher the anxiety.	Change from 3 months postoperative to 1 year postoperative
Secondary	Psychosocial factors: anxiety	Measured with Hospital Anxiety and Depression Scale (HADS), subscale anxiety. Minimum score is 0, maximum score is 21. The higher the score, the higher the anxiety.	Baseline (preoperative)
Secondary	Psychosocial factors: anxiety	Measured with Hospital Anxiety and Depression Scale (HADS), subscale anxiety. Minimum score is 0, maximum score is 21. The higher the score, the higher the anxiety.	3 months postoperative
Secondary	Psychosocial factors: anxiety	Measured with Hospital Anxiety and Depression Scale (HADS), subscale anxiety. Minimum score is 0, maximum score is 21. The higher the score, the higher the anxiety.	1 year postoperative
Secondary	Psychosocial factors: depression	Measured with Hospital Anxiety and Depression Scale (HADS), subscale depression. Minimum score is 0, maximum score is 21. The higher the score, the higher the depression.	Change from baseline (preoperative) to 3 months postoperative
Secondary	Psychosocial factors: depression	Measured with Hospital Anxiety and Depression Scale (HADS), subscale depression. Minimum score is 0, maximum score is 21. The higher the score, the higher the depression.	Change from baseline (preoperative) to 1 year postoperative
Secondary	Psychosocial factors: depression	Measured with Hospital Anxiety and Depression Scale (HADS), subscale depression. Minimum score is 0, maximum score is 21. The higher the score, the higher the depression.	Change from 3 months postoperative to 1 year postoperative
Secondary	Psychosocial factors: depression	Measured with Hospital Anxiety and Depression Scale (HADS), subscale depression. Minimum score is 0, maximum score is 21. The higher the score, the higher the depression.	Baseline (preoperative)
Secondary	Psychosocial factors: depression	Measured with Hospital Anxiety and Depression Scale (HADS), subscale depression. Minimum score is 0, maximum score is 21. The higher the score, the higher the depression.	3 months postoperative
Secondary	Psychosocial factors: depression	Measured with Hospital Anxiety and Depression Scale (HADS), subscale depression. Minimum score is 0, maximum score is 21. The higher the score, the higher the depression.	1 year postoperative
Secondary	Functional factors: Maximal voluntary muscle strength m. Hamstrings	Strength m. Hamstrings of both legs, measured with Biodex System 4 pro - dynamometer	Change from baseline (preoperative) to 3 months postoperative
Secondary	Functional factors: Maximal voluntary muscle strength m. Hamstrings	Strength m. Hamstrings of both legs, measured with Biodex System 4 pro - dynamometer	Change from baseline (preoperative) to 1 year postoperative
Secondary	Functional factors: Maximal voluntary muscle strength m. Hamstrings	Strength m. Hamstrings of both legs, measured with Biodex System 4 pro - dynamometer	Change from 3 months postoperative to 1 year postoperative
Secondary	Functional factors: Maximal voluntary muscle strength m. Hamstrings	Strength m. Hamstrings of both legs, measured with Biodex System 4 pro - dynamometer	3 months postoperative
Secondary	Functional factors: Maximal voluntary muscle strength m. Hamstrings	Strength m. Hamstrings of both legs, measured with Biodex System 4 pro - dynamometer	Baseline (preoperative)
Secondary	Functional factors: Maximal voluntary muscle strength m. Hamstrings	Strength m. Hamstrings of both legs, measured with Biodex System 4 pro - dynamometer	1 year postoperative
Secondary	Functional factors: Maximal voluntary muscle strength m. Quadriceps	Strength m. Quadriceps of both legs, measured with Biodex System 4 pro - dynamometer	Change from baseline (preoperative) to 3 months postoperative
Secondary	Functional factors: Maximal voluntary muscle strength m. Quadriceps	Strength m. Quadriceps of both legs, measured with Biodex System 4 pro - dynamometer	Change from baseline (preoperative) to 1 year postoperative
Secondary	Functional factors: Maximal voluntary muscle strength m. Quadriceps	Strength m. Quadriceps of both legs, measured with Biodex System 4 pro - dynamometer	Change from 3 months postoperative to 1 year postoperative
Secondary	Functional factors: Maximal voluntary muscle strength m. Quadriceps	Strength m. Quadriceps of both legs, measured with Biodex System 4 pro - dynamometer	Baseline (preoperative)
Secondary	Functional factors: Maximal voluntary muscle strength m. Quadriceps	Strength m. Quadriceps of both legs, measured with Biodex System 4 pro - dynamometer	3 months postoperative
Secondary	Functional factors: Maximal voluntary muscle strength m. Quadriceps	Strength m. Quadriceps of both legs, measured with Biodex System 4 pro - dynamometer	1 year postoperative
Secondary	Functional factors: proprioceptive accuracy	Proprioception of the knee of both legs, measured with inclinometer	Change from baseline (preoperative) to 3 months postoperative
Secondary	Functional factors: proprioceptive accuracy	Proprioception of the knee of both legs, measured with inclinometer	Change from baseline (preoperative) to 1 year postoperative
Secondary	Functional factors: proprioceptive accuracy	Proprioception of the knee of both legs, measured with inclinometer	Change from 3 months postoperative to 1 year postoperative
Secondary	Functional factors: proprioceptive accuracy	Proprioception of the knee of both legs, measured with inclinometer	Baseline (preoperative)
Secondary	Functional factors: proprioceptive accuracy	Proprioception of the knee of both legs, measured with inclinometer	3 months postoperative
Secondary	Functional factors: proprioceptive accuracy	Proprioception of the knee of both legs, measured with inclinometer	1 year postoperative
Secondary	Functional factors: leg strength and endurance	Measured with 30 seconds Timed Chair-Stand-Test	Change from baseline (preoperative) to 3 months postoperative
Secondary	Functional factors: leg strength and endurance	Measured with 30 seconds Timed Chair-Stand-Test	Change from baseline (preoperative) to 1 year postoperative
Secondary	Functional factors: leg strength and endurance	Measured with 30 seconds Timed Chair-Stand-Test	Change from 3 months postoperative to 1 year postoperative
Secondary	Functional factors: leg strength and endurance	Measured with 30 seconds Timed Chair-Stand-Test	Baseline (preoperative)
Secondary	Functional factors: leg strength and endurance	Measured with 30 seconds Timed Chair-Stand-Test	3 months postoperative
Secondary	Functional factors: leg strength and endurance	Measured with 30 seconds Timed Chair-Stand-Test	1 year postoperative
Secondary	Patient demographics	measured with Knee Society Scoring System (KSS): subscale patient demographics (nominal)	Baseline (preoperative)
Secondary	Alignment	measured with Knee Society Scoring System (KSS): subscale objective knee score 'alignment': weight-bearing anterior-posterior radiograph measuring the femoral-tibial (Anatomic) axis. Minimum is 0, maximum is 25. The higher the score, the better the alignment.	Baseline (preoperative)
Secondary	Instability	measured with Knee Society Scoring System (KSS): subscale objective knee score 'instability'. Minimum is 0, maximum is 25. The higher the score, the better the stability.	Baseline (preoperative)
Secondary	Joint motion	measured with Knee Society Scoring System (KSS): subscale objective knee score 'joint motion'. Minimum is 0, maximum can be higher than 25. One point for every joint motion of 5 degrees. The higher the score, the better the joint motion.	Baseline (preoperative)
Secondary	Pain symptoms	measured with Knee Society Scoring System (KSS): subscale symptoms. Minimum score is 0, maximum score is 25. The higher the score, the worse the pain symptoms.	Change from baseline (preoperative) to 3 months postoperative
Secondary	Pain symptoms	measured with Knee Society Scoring System (KSS): subscale symptoms. Minimum score is 0, maximum score is 25. The higher the score, the worse the pain symptoms.	Change from baseline (preoperative) to 1 year postoperative
Secondary	Pain symptoms	measured with Knee Society Scoring System (KSS): subscale symptoms. Minimum score is 0, maximum score is 25. The higher the score, the worse the pain symptoms.	Change from 3 months postoperative to 1 year postoperative
Secondary	Pain symptoms	measured with Knee Society Scoring System (KSS): subscale symptoms. Minimum score is 0, maximum score is 25. The higher the score, the worse the pain symptoms.	Baseline (preoperative)
Secondary	Pain symptoms	measured with Knee Society Scoring System (KSS): subscale symptoms. Minimum score is 0, maximum score is 25. The higher the score, the worse the pain symptoms.	3 months postoperative
Secondary	Pain symptoms	measured with Knee Society Scoring System (KSS): subscale symptoms. Minimum score is 0, maximum score is 25. The higher the score, the worse the pain symptoms.	1 year postoperative
Secondary	Patient expectations	measured with Knee Society Scoring System (KSS): subscale patient expectations. Minimum score is 0, maximum score is 15. The higher the score, the higher the patient's opinion on the extent to which the patient expects that the operation will improve their knee pain, and their ability to perform their activities of daily living and recreational activities	Baseline (preoperative)
Secondary	Patient expectations fulfillment	measured with Knee Society Scoring System (KSS): subscale patient expectations. Minimum score is 0, maximum score is 15. The higher the score, the higher the patient's opinion on the extent to which the outcome after the operation has met the patient's pre-operative expectations with respect to pain and function	3 months postoperative
Secondary	Patient expectations fulfillment	measured with Knee Society Scoring System (KSS): subscale patient expectations. Minimum score is 0, maximum score is 15. The higher the score, the higher the patient's opinion on the extent to which the outcome after the operation has met the patient's pre-operative expectations with respect to pain and function	1 year postoperative
Secondary	Patient expectations fulfillment	measured with Knee Society Scoring System (KSS): subscale patient expectations. Minimum score is 0, maximum score is 15. The higher the score, the higher the patient's opinion on the extent to which the outcome after the operation has met the patient's pre-operative expectations with respect to pain and function	Change from 3 months postoperative to 1 year postoperative
Secondary	Patient satisfaction	measured with Knee Society Scoring System (KSS): subscale patient satisfaction. Minimum score is 0, maximum score is 40. The higher the score, the more satisfied the patient feels with their knee.	Change from baseline (preoperative) to 3 months postoperative
Secondary	Patient satisfaction	measured with Knee Society Scoring System (KSS): subscale patient satisfaction. Minimum score is 0, maximum score is 40. The higher the score, the more satisfied the patient feels with their knee.	Change from baseline (preoperative) to 1 year postoperative
Secondary	Patient satisfaction	measured with Knee Society Scoring System (KSS): subscale patient satisfaction. Minimum score is 0, maximum score is 40. The higher the score, the more satisfied the patient feels with their knee.	Change from 3 months postoperative to 1 year postoperative
Secondary	Patient satisfaction	measured with Knee Society Scoring System (KSS): subscale patient satisfaction. Minimum score is 0, maximum score is 40. The higher the score, the more satisfied the patient feels with their knee.	Baseline (preoperative)
Secondary	Patient satisfaction	measured with Knee Society Scoring System (KSS): subscale patient satisfaction. Minimum score is 0, maximum score is 40. The higher the score, the more satisfied the patient feels with their knee.	3 months postoperative
Secondary	Patient satisfaction	measured with Knee Society Scoring System (KSS): subscale patient satisfaction. Minimum score is 0, maximum score is 40. The higher the score, the more satisfied the patient feels with their knee.	1 year postoperative
Secondary	Functional score	measured with Knee Society Scoring System (KSS): subscale functional score. Minimum score is 0, maximum score is 100. The higher the score, the better the functionality of the patient	Change from baseline (preoperative) to 3 months postoperative
Secondary	Functional score	measured with Knee Society Scoring System (KSS): subscale functional score. Minimum score is 0, maximum score is 100. The higher the score, the better the functionality of the patient	Change from baseline (preoperative) to 1 year postoperative
Secondary	Functional score	measured with Knee Society Scoring System (KSS): subscale functional score. Minimum score is 0, maximum score is 100. The higher the score, the better the functionality of the patient	Change from 3 months postoperative to 1 year postoperative
Secondary	Functional score	measured with Knee Society Scoring System (KSS): subscale functional score. Minimum score is 0, maximum score is 100. The higher the score, the better the functionality of the patient	Baseline (preoperative)
Secondary	Functional score	measured with Knee Society Scoring System (KSS): subscale functional score. Minimum score is 0, maximum score is 100. The higher the score, the better the functionality of the patient	3 months postoperative
Secondary	Functional score	measured with Knee Society Scoring System (KSS): subscale functional score. Minimum score is 0, maximum score is 100. The higher the score, the better the functionality of the patient	1 year postoperative
Secondary	Metabolic factors: Fat mass	Measured with Bio-electrical Impedance Analyses (BIA)	Change from baseline (preoperative) to 3 months postoperative
Secondary	Metabolic factors: Fat mass	Measured with Bio-electrical Impedance Analyses (BIA)	Change from baseline (preoperative) to 1 year postoperative
Secondary	Metabolic factors: Fat mass	Measured with Bio-electrical Impedance Analyses (BIA)	Change from 3 months postoperative to 1 year postoperative
Secondary	Metabolic factors: Fat mass	Measured with Bio-electrical Impedance Analyses (BIA)	Baseline (preoperative)
Secondary	Metabolic factors: Fat mass	Measured with Bio-electrical Impedance Analyses (BIA)	3 months postoperative
Secondary	Metabolic factors: Fat mass	Measured with Bio-electrical Impedance Analyses (BIA)	1 year postoperative
Secondary	Metabolic factors: Lean mass	Measured with Bio-electrical Impedance Analyses (BIA)	Change from baseline (preoperative) to 3 months postoperative
Secondary	Metabolic factors: Lean mass	Measured with Bio-electrical Impedance Analyses (BIA)	Change from baseline (preoperative) to 1 year postoperative
Secondary	Metabolic factors: Lean mass	Measured with Bio-electrical Impedance Analyses (BIA)	Change from 3 months postoperative to 1 year postoperative
Secondary	Metabolic factors: Lean mass	Measured with Bio-electrical Impedance Analyses (BIA)	Baseline (preoperative)
Secondary	Metabolic factors: Lean mass	Measured with Bio-electrical Impedance Analyses (BIA)	3 months postoperative
Secondary	Metabolic factors: Lean mass	Measured with Bio-electrical Impedance Analyses (BIA)	1 year postoperative
Secondary	Metabolic factors: Body mass index (BMI)	Measured with length of patient (cm) and weight of patient (kg)	Change from baseline (preoperative) to 3 months postoperative
Secondary	Metabolic factors: Body mass index (BMI)	Measured with length of patient (cm) and weight of patient (kg)	Change from baseline (preoperative) to 1 year postoperative
Secondary	Metabolic factors: Body mass index (BMI)	Measured with length of patient (cm) and weight of patient (kg)	Change from 3 months postoperative to 1 year postoperative
Secondary	Metabolic factors: Body mass index (BMI)	Measured with length of patient (cm) and weight of patient (kg)	Baseline (preoperative)
Secondary	Metabolic factors: Body mass index (BMI)	Measured with length of patient (cm) and weight of patient (kg)	3 months postoperative
Secondary	Metabolic factors: Body mass index (BMI)	Measured with length of patient (cm) and weight of patient (kg)	1 year postoperative
Secondary	Metabolic factors: body composition	Measured with Bioelectrical Impedance Analysis (BIA)	Baseline (preoperative), 3 months postoperative, 1 year postoperative.
Secondary	Metabolic factors: venous blood sample	Measured with A1C test or glycohemoglobin test	Change from baseline (preoperative) to 3 months postoperative
Secondary	Metabolic factors: venous blood sample	Measured with A1C test or glycohemoglobin test	Change from baseline (preoperative) to 1 year postoperative
Secondary	Metabolic factors: venous blood sample	Measured with A1C test or glycohemoglobin test	Change from 3 months postoperative to 1 year postoperative
Secondary	Metabolic factors: venous blood sample	Measured with A1C test or glycohemoglobin test	Baseline (preoperative)
Secondary	Metabolic factors: venous blood sample	Measured with A1C test or glycohemoglobin test	3 months postoperative
Secondary	Metabolic factors: venous blood sample	Measured with A1C test or glycohemoglobin test	1 year postoperative.
Secondary	Structural factors	Measured with Kellgren and Lawrence scale on radiography	Baseline (preoperative)
Secondary	Inflammatory factors: signs of inflammation	Measured with the C-reactive protein levels in blood sample (collected from patient record)	Baseline (preoperative)
Secondary	Anesthetic procedure	General anesthesia, spinal anesthesia or combination with peripheral block	During surgery
Secondary	Clinical pain score	Measured with numeric rating pain scale	day 1 and 2 postoperative