Potential prognostic factors
| Type/Mode | Psychometric properties/Clinimetrics | T1: Baseline 2–3 weeks pre RCR | T2: 12–14 weeks post RCR | T3: 12–14 months post RCR | |
| Potential prognostic factors | |||||
| Psychosocial factors | |||||
| 1 Catastrophic thinking | PCS | German PCS showed same factor structure like original version and acceptable to good reproducibility.53 Validated in patients with low back pain. | x | x | x |
| Description | The PCS assesses whether or not there is presence of catastrophic thinking about pain. Thirteen items entail aspects about different thoughts and feelings while experiencing pain. Items are scored on a 5-point Likert scale. Higher scores indicate more severe catastrophic thinking about pain. There is a total score and a score for three subscales (eg, helplessness, magnification and rumination).54 | ||||
| 2 Perceived distress | PSS | The German version showed good psychometric properties like validity and reliability in the general population.55 | x | x | x |
| The PSS-10 includes 10 questions and assesses the degree to which life has been experienced as unpredictable, uncontrollable and overloaded in the past months. The questions are answered by ‘yes’ (1) or ‘no’ (0). The questions are general in nature and therefore the usage for patients with shoulder pain undergoing RCR is reasonable. | |||||
| 3 Perceptions about injury | IPQ-R | The clinimetric properties for musculoskeletal pain are reported to be sufficient.56 For rotator cuff tears and rotator cuff repair, the word ‘injury’ seems to be more adequate, therefore we exchanged the word illness (German: Krankheit) with injury (German: Verletzung). | x | x | x |
| Description | Designed to assess the cognitive and emotional representations of illness/injury. The items are formed by experiences, provided information and interpretation of symptoms. The IPQ-R is not disease specific and may be used in any group of interest.57 The questionnaire has nine dimensions of injury perception: (1) Timeline (acute/chronic), (2) Consequences, (3) Personal control, (4) Treatment control, (5) Injury coherence, (6) Timeline cyclical, (7) Emotional representations as well as (8) Identity and (9) Causes. We amalgamated dimensions (1) and (6) into ‘timeline’ and dimensions (3) and (4) into ‘control’ and end up with six subscales for illness perceptions and one for causes. Further it includes three domains.58 59 The first domain is called illness identity, the second is called the beliefs domain and the third is labelled as the consequence domain.60 The authors adjusted the questionnaire to the cohort and exchanged illness with injury. The 32 injury perceptions and 18 causes answers are captured on a 5-point Likert scale from ‘strongly disagree’ (1) to ‘strongly agree’ (5). | ||||
| 4 Expectations | Study designed, 6 Questions about expectations | Lack of German-translated questionnaires in the field. Consequently, the research team formulated six questions based on literature including the study of the MODEMS.12 35 | x | – | – |
| Description | Patients’ expectations will be assessed using five questions: (1) expected shoulder function in percentage at 12 weeks post RCR, (2) expected shoulder function at 12 month postop, (3) expected symptom reduction in percentage at 12 weeks post RCR, (4) expected symptom reduction in percentage at 12 months post RCR, (5a) and (5b) open questions about driver for high (>80%) or low (<80%) expectations for shoulder function and symptom reduction. | ||||
| Sleep | |||||
| Study designed, 4 Questions about sleep | Due to study feasibility, we formulated four questions. Because sleep assessments were not validated in German language, or too long to integrate. | x | x | x | |
| Description | Four questions regarding 5) sleep quality, 6) sleep efficiency, 7) sleep disturbance, 8) number of awakenings per night. The first question is transformed from the PSQI, for sleep quality and is rated on a 4-point Likert Scale. The question 2 to 3 are formulated by suggestion from research61 and adapted to shoulder pain by the first author. | ||||
| Central Pain Processing | |||||
| 9 Self-reported symptoms of central Sensitisation | CSI | It is a high-quality measurement tool, with high construct validity and test-retest reliability. The defined cut-off point is at 40 points.62 German version is to be validated by the research group among Laekemann. Signed contract for the usage of this version. | x | x | x |
| Description | The original English questionnaire was developed in 201163 to assess key symptoms in relation to CSS. It consists of two parts: Part A with 25 items relating to pain, psychosocial aspects, cognitive and functional aspects; and Part B with seven different CSSs, like restless legs, irritable bowel and multiple chemical sensitivities and three disorders like neck pain (whiplash), depression and anxiety or panic attacks. | ||||
| 10 TS | Frey hair filament, 10 g calibrated | No factor analysis available for testing loading of TS for CPP. TS is a common method in research to measure CPP.64 | x | x | x |
| Description | Locations for applications will be at two local and one remote site: (1) Local painful site: the most painful site of the shoulder is marked on the skin with a pen, indicated on a body chart and noted in the assessors’ documents, to determine the site for repeated measures. (2) Local standardised site: at ipsilateral upper trapezius muscle at the midpoint between C7 spinous process and the acromion. (3) Remote site is standardised at the contralateral muscle belly of tibialis anterior at 5 cm distal to the tibial tuberosity and 2 cm laterally.65 The patient is asked to rate the first touch on an NRS from 0 (no pain at all) to 10 (worst imaginable pain). Then the measurement is repeated once per second (1 Hz) for 30 s on a surface of maximum 1 cm2,50 The standardisation of the frequency is important, as wind-up of the C-fibres only arrives if the stimulus is provided at least once every 3 s (<0.33 Hz).66 After the 30 s application, the patient is asked to rate the last touch on an NRS. The difference between the last and the first rating is calculated. Fifteen seconds after the test, patients need to rate any ongoing pain sensation on NRS again.67 Patients will be advised that the method does not aim to measure pain tolerance68 and a number should only be given if the sensation was burning, stabbing, pulling or gnawing. | ||||
| 11 CH | Ice pack | No factor analysis available for testing loading of CH for CPP. CH is a common method in research to measure CPP.64 | x | x | x |
| Description | CH is measured with a cold pack, kept in the deep freezer which is simulating ice cubes for the ice test.69 Locations for applications will be at two local and two remote sites: (1) Local painful site: the most painful site of the shoulder is marked on the skin with a pen, indicated on a body chart and noted in the assessors’ documents, to determine the site for repeated measures. (2) Local standardised site: at ipsilateral upper trapezius muscle at the midpoint between C7 spinous process and the acromion. (3) Remote site is standardised at the contralateral muscle belly of tibialis anterior at 5 cm distal to the tibial tuberosity and 2 cm laterally.65 The cold application is kept for 10 s, and the patients will rate the experienced pain on a NRS from 0 (no pain at all) to 10 (worst imaginable pain).69 Patients will be advised the measure does not aim for pain tolerance and their pain should be reported if a burning, stabbing, pulling or gnawing sensation is felt.68 | ||||
| 12 PPT | Wagner Instruments | No factor analysis available for testing loading of PPT for CPP. PPT is a common method in research to measure CPP.64 | x | x | x |
| Description | PPT represents a static psychophysical test, which measures the point of pressure evolving into pain. Its report of large to nearly perfect reliability in neck pain patients, demonstrates its great potential as measurement tool also for the present cohort.70 The measurements will be conducted by digital hand-held pressure algometer with a rubber tip of approximately 1 cm² (FPX 50, FORCE TEN by Wagner Instruments), increasing pressure will be given perpendicular to the skin.71 Measurements are taken at five standardised sites. 1. Two cm caudal from the acromion at the muscle belly of middle deltoid, bilaterally. 2. At the muscle belly in middle of the upper trapezius, bilaterally. 3. At the contralateral muscle belly of tibialis anterior at 5 cm distal to the tibial tuberosity and 2 cm laterally, as remote site.65 All measurements will be repeated once and the mean PPT in kilopascals per site will be calculated. | ||||
| 13 Neuropathic pain differential diagnosis | DN4 | The DN4 showed more sensitivity and specificity in preselected cohorts with respect of neuropathic pain detection, and it is strongly advised to obtain a thorough clinical assessment when diagnosing neuropathic pain.72 | x | x | x |
| Description | Short and easy to administer assessment, which consists of a subjective part, including seven symptoms (patient-rated) and an objective part including three signs (physician-rated). The cut-off point is 4 points, the total of points is 10, indicating that neuropathic pain mechanisms may be involved.72 | ||||
| 14 Pain surface/distribution | Body chart | x | x | x | |
| Description | Patients report their pain location and pain distribution. The assessor is painting the body chart at the same time as the patient reports it. Calculation of pain surface (in percentage) will be analysed using the Margolis Bodychart scoring system.73 | ||||
| Additional prognostic factors | |||||
| 15 Age | Date of birth | x | – | – | |
| 16 Sex | Female/male/other | x | – | – | |
| 17 Cause of tear | Traumatic vs non-traumatic | x | – | – | |
| 18 BMI | kg and cm | x | – | – | |
BMI, body mass index; CH, cold hyperalgesia; CPP, central pain processing; CSI, Central Sensitisation Inventory; CSSs, central sensitivity symptoms; DN4, Douleur Neuropathique 4; IPQ-R, Injury Perception Questionnaire-Revised; MODEMS, Musculoskeletal Outcomes Data Evaluation and Management System; NRS, Numeric Rating Scale; PCS, Pain Catastrophising Scale; PPT, pressure pain threshold; PSQI, Pittsburgh Sleep Quality Index; PSS, Perceived Stress Scale; RCR, rotator cuff repair; TS, temporal summation.