ABSTRACT
Objectives: A prospective observational cohort study was conducted to (1) determine the prevalence of Mechanical Diagnosis and Therapy (MDT) syndromes for patients with shoulder impairments and (2) report the interaction between MDT classification and clinical outcomes, including pain intensity and disability, at discharge.
Methods: Clinical outcome measures were completed at intake and discharge by 115 patients. A two-way mixed model analysis of variance with subsequent pairwise comparisons was done to examine differences in clinical outcomes between the following MDT classifications: Shoulder Derangement, Shoulder Dysfunction, and Other.
Results: The primary findings were that (1) 44.3 (35.3, 53.4), 40.0 (31.0, 48.9), and 15.6 (9.0, 22.3) percent of patients’ conditions were classified as Shoulder Derangement, Shoulder Dysfunction, and Other, respectively, (2) all groups managed via MDT methods made clinically significant improvements in disability and pain intensity at discharge, (3) a statistically significant difference in pain intensity at discharge was observed between the Shoulder Derangement and the Shoulder Dysfunction classifications (p = 0.01), and (4) patients with the Shoulder Derangement classification were discharged, on average, 35.3 days earlier than the Shoulder Dysfunction classification and 28.3 days earlier than the Other classification.
Discussion: This study confirms previous reports that the Shoulder Derangement and Shoulder Dysfunction classifications are common and represent distinct clinical trajectories when assessed and managed via MDT methods.
KEYWORDS: Shoulder pain, directional preference, McKenzie, orthopedic, musculoskeletal, classification
Introduction
Establishing a tissue-specific shoulder diagnosis is difficult at best. Numerous reports have shown unacceptable levels of reliability [1,2] and validity [3–6] for the clinical tests used to establish a pathoanatomical shoulder diagnosis. Furthermore, radiological studies of the shoulder are subject to a high prevalence of incidental findings, and structural abnormalities including rotator cuff pathology [7–10] and labral tears [11,12] commonly occur in asymptomatic individuals. Unreliable tests coupled with high rates of false positives has led to a misunderstanding of the cause of shoulder symptoms and, consequently, suboptimal clinical and economic outcomes.
A treatment-based approach to shoulder pain assessment and management known as Mechanical Diagnosis and Therapy (MDT) does not rely on radiography, orthopedic special tests, or tissue-specific diagnoses [13]. MDT utilizes a classification methodology centered on symptomatic and mechanical responses to end-range movements. Patients’ conditions are classified into one of four categories, which guide treatment and establish prognosis: Derangement, Dysfunction, Posture, and Other. Derangement is characterized by rapid and lasting improvement in symptoms, range of movement, and function. Dysfunction describes structurally impaired or shortened soft tissues due to scarring or adaptive shortening and, in the extremity, can be further sub-classified into Articular Dysfunction and Contractile Dysfunction. Articular Dysfunction is characterized by intermittent pain consistently produced only at a restricted end-range of motion with no rapid change of symptoms, range of motion, or function. Contractile Dysfunction displays intermittent pain consistently produced by loading the musculotendinous unit. Postural syndrome occurs in normal tissues subjected to abnormal stress during sustained positioning; otherwise, the physical examination is unremarkable. The Other subgroups are considered when none of the former syndrome patterns are present (Appendix).
The MDT approach has been long established [13] and recent studies have shown intriguing results supportive of the utility of the system. Reliability of the MDT approach has been widely studied in the spine [14–19] and newer evidence indicates that the MDT system is a reliable method to classify patients with extremity disorders [20]. ‘Very good’ agreement (k = 0.90) was found for classifying patients’ shoulder conditions via MDT methods [21]. A case study [22] and case series [23] showed remarkable clinical outcomes and presented the unique format to assess, diagnose, and treat shoulder challenges via MDT methods. Kidd [24] presented a case study of a patient with a Shoulder Derangement and the Hawkins-Kennedy, Liftoff, and Empty Can test were found positive indicating rotator cuff and sub-acromial impingement pathology; the tests changed from positive to negative in response to MDT procedures during the first session and remained negative until the patient rapidly and fully recovered within two weeks. A larger, prospective study confirmed these findings by showing that the overall agreement of commonly used orthopedic special tests was affected by the presence of Derangement [25]. The authors recommended that clinicians consider the presence of Derangement when using orthopedic special tests for the shoulder. Another prospective cohort study by Heidar Abady et al analyzed clinical outcomes of 93 patients with shoulder pain that were classified via MDT methods [26]. The findings of the investigation indicate that patients’ conditions responded as expected relative to their MDT operational definition in terms of pain, disability, and frequency of discharge; Derangement and Spinal classifications had statistically significant lower pain and disability outcomes relative to the Dysfunction classification. Furthermore, the frequency of discharge at four weeks was 83%, 82%, and 15% for the Derangement, Spinal, and Dysfunction classifications, respectively.
Previous research has shown the Derangement classification to be the most prevalent classification in patients with spinal symptoms; however, limited data are available for patients with shoulder impairments. Only two reports exist indicating the prevalence of Shoulder Derangement to be 42.5% [27] and 37.6% [26]. Furthermore, only one MDT prospective study of the shoulder exists which analyzed the interaction between classification and outcomes in patients with shoulder impairments [26]. However, this investigation focused its analysis on the Shoulder Derangement, Shoulder Dysfunction, and Spinal classification and excluded the Other classification; no prevalence or clinical outcome data exist regarding the Other classification for the shoulder. The aim of this investigation was to (1) determine the prevalence of MDT syndromes (i.e. Shoulder Derangement, Shoulder Dysfunction, Posture, and Other) for patients with shoulder impairments, and (2) report the interaction between classification and clinical outcomes. The hypotheses were that (1) the most prevalent classification would be Shoulder Derangement, (2) the Shoulder Derangement classification would demonstrate clinically significant differences in disability and pain intensity relative to the Shoulder Dysfunction, Posture, and Other classifications at discharge, and (3) the Shoulder Derangement classification would be discharged earlier and demonstrate statistically significant differences in duration of care relative to the Shoulder Dysfunction classification. This study adds to the growing amount of evidence for the classification of shoulder challenges via MDT methods and provides new insight into understanding the clinical profile of patients with shoulder pain classified via the MDT syndromes.
Methodology
A prospective observational cohort study was conducted and data were collected from 261 consecutive patients who met the inclusion criteria of the study. Patients were included in the study if they presented to any of the four orthopedic physical therapy clinics (i.e. Florida, Alabama, South Carolina, and Oklahoma) during 2014 with shoulder impairments. Patients were excluded from the study by the examining clinician if (1) their shoulder impairment was deemed to have cervical spine involvement (i.e. the MDT qualified examiner determined that the condition exhibited improvement in shoulder symptoms and/or range of motion during an MDT evaluation with cervical and/or thoracic spine intervention) and (2) they had shoulder surgery within the preceding 12 months. The Florida State University Institutional Review Board for Protection of Human Subjects and the Florida Agricultural and Mechanical Institutional Review Board for Protection of Human Subjects approved the project. Since the study did not include any change to typical physical therapy practice, patient informed consent was not required for the analysis and reporting of data.
Eight physical therapists and one chiropractor that worked in four Certified McKenzie Clinics participated in the study. All clinicians had a certification in MDT (Cert. MDT) and four clinicians had a diploma in MDT (Dip. MDT). Patients with non-specific shoulder pain were exclusively assessed, classified, and treated via MDT methods [13]. Physical examination procedures included repeated and sustained end-range movements while clinicians monitored symptomatic and mechanical (i.e. range of movement related constructs) responses. Patients’ shoulder challenges were classified into one of four classifications: Shoulder Derangement, Shoulder Dysfunction, Posture, and Other. The Shoulder Dysfunction category was further sub-classified into Shoulder Articular Dysfunction and Shoulder Contractile Dysfunction. The Other categories for the shoulder can be found in the Appendix. The operational definitions for the MDT classifications are described by McKenzie [13]. Acceptable levels of reliability (k = 0.90) for classifying patients’ shoulder conditions among trained clinicians via MDT methods have been demonstrated [21].
Treatments were not recorded; however, all patients received an MDT evaluation, and their non-specific shoulder pain was classified and subsequently treated with interventions matched to the MDT classification. MDT clinicians used unidirectional repeated and sustained movements to isolate cause and effect relationships. The treatment was augmented with the judicious use of manual therapy techniques and individualized education relative to classification [13].
Clinicians collected patient-reported and clinical examination responses at intake, regularly throughout the care episode, and at discharge. The managing clinicians were responsible for determining and reporting inclusion, exclusion, and discharge status. Two primary patient-reported outcomes were assessed: pain intensity and patient self-reported disability via the Numeric Pain Rating Scale (NPRS) and the shortened version of the Disabilities of the Arm, Shoulder, and Hand (DASH), the Quick DASH, respectively. Pain intensity reported by the patient within ‘the last few days’ was assessed using an 11-point NPRS ranging from 0 (‘No pain’) to 10 (‘Worst Pain Imaginable’) [28]. The NPRS is a reliable pain assessment tool and has excellent internal consistency [29]. The MCID for the NPRS for patients with shoulder pain has been shown to be 2.17 [30]. The QuickDASH is a self-report disability questionnaire that measures the degree of difficulty in performing various physical activities due to a shoulder, arm, or hand challenge. Scores range from 0 to 100, with higher scores indicating greater disability. The QuickDASH has been shown to have acceptable psychometric properties for clinical use and an MCID of 15.91 [31,32].
Patient-reported outcomes were collected by the managing clinician at intake, regularly throughout the care episode, and at discharge through patient self-report and clinician-reported methods. Patients were asked to complete self-report measures (i.e. the NPRS and the QuickDASH) immediately before intake, at regular intervals determined by the managing clinician immediately after follow-up examinations, and then at discharge. The managing clinicians were responsible for determining discharge from physical therapy and reported the duration of care (i.e. the total number of days from intake to discharge from physical therapy).
Patient characteristics were collected at intake by the managing clinicians through patient self-report methods. The following continuous variables were measured: age, number of medications taken for the condition, symptom acuity, pain intensity score at intake, disability score at intake, and the number of comorbid conditions. The following categorical variables were measured: gender.
The primary aim of this investigation was to (1) determine the prevalence of patients with shoulder impairments classified into the MDT syndromes (i.e. Shoulder Derangement, Shoulder Dysfunction, Posture, and Other) and (2) analyze the interaction between classification and outcomes. Descriptive statistics were calculated for patient characteristics including MDT classifications, patients with intake data only, and patients with intake and discharge data. Chi-square tests of independence (dichotomous and categorical data) or two-sample t-tests (continuous data) were performed to compare patient characteristics and determine equivalence between patients with first examination data only and patients with first examination and follow-up data. Constructs measured approximated a normal distribution, and the significance level for all tests was set at p < .05. Reasons for non-participation were recorded at each level of the study. Prevalence of MDT classification categories (95% CI) was reported for patients with a confirmed MDT classification. The interaction among MDT classification at intake and clinical outcomes (i.e. QuickDASH score, NPRS score, and duration of care) at discharge was analyzed using a two-way mixed model ANOVA and subsequent two-sample t-tests for significant interaction considering a normal distribution. A Bonferroni correction for significant p-values to avoid type 1 error was applied. Difference scores were calculated, or the difference between the clinical outcome measures (i.e. disability, pain intensity, or duration of care) at intake and discharge and referenced these values to the MCID. The average duration of care was calculated for patients with intake and discharge data and adjusted by MDT classification.
Results
During the study period, 261 consecutive patients entered four outpatient physical therapy clinics (Figure 1). In total, 38 patients did not complete intake data collection resulting in a participation rate of 85%. Reasons for not commencing data collection included: Late for Appointment (76.4%), Seen on a Single Occasion and Provided with a HEP Only (10.5%), Cognitive Deficits (5.3%), Reading Ability (5.3%), and Language Difficulties (2.5%). The characteristics of the patients are displayed in Table 1. For patients with intake and discharge data (n = 115; 52% completion rate), reasons for not completing discharge data collection were: Unable to Reschedule a Follow-up Appointment (60.0%) and Other (40.0%). Compared to patients with intake and discharge data, patients with intake data only did not significantly differ based on age (p = 0.15), disability at intake (p = 0.25), pain intensity at intake (p = 0.95), gender (x2 = 2.69; df = 1;p-value = 0.10), symptom duration (x2 = 2.73; df = 2;p-value = 0.26), medication use (x2 = 0.63; df = 1;p-value = 0.43), number of comorbidities (x2 = 7.16; df = 3;p-value = 0.07), and number of previous knee surgeries (x2 = 0.29; df = 1;p-value = 0.59).
Figure 1.
Flow of patients.
Table 1.
Patient characteristics.
| Characteristics | Intake Only (n = 108) | Intake and Discharge Data (n = 115) |
|---|---|---|
| Age (y) | 52.6 ± 14.4 (15–83) | 49.4 ± 17.6 (4–85) |
| Missing | 1.8% | 0.8% |
| Gender | ||
| Male | 41.7% | 53.0% |
| Female | 56.5% | 46.1% |
| Missing | 1.8% | 0.8% |
| Symptom Acuity | ||
| Acute (0–2 weeks) | 10.2% | 17.4% |
| Sub-Acute (3–11 weeks) | 28.7% | 29.6% |
| Chronic (≥12 weeks) | 60.2% | 52.2% |
| Missing | 0.9% | 0.8% |
| Surgical History | ||
| None | 98.1% | 96.5% |
| 1 or More | 0.9% | 1.7% |
| Missing | 0.9% | 1.7% |
| Medication for Condition | ||
| None | 62.9% | 61.7% |
| 1 or More | 29.6% | 36.5% |
| Missing | 7.4% | 1.7% |
| Number of Comorbid Conditions | ||
| None | 24.1% | 38.3% |
| 1 | 29.6% | 27.0% |
| 2 or 3 | 26.8% | 25.2% |
| 4 or more | 17.6% | 8.7% |
| Missing | 1.8% | 0.8% |
| Intake QuickDASH | 37.8 ± 23.2 (0–99) | 34.6 ± 16.9 (0–77) |
| Missing | 0.0% | 0.0% |
| Intake NPRS | 4.9 ± 2.7 (0–10) | 5.0 ± 2.3 (0–10) |
| Missing | 0.0% | 0.0% |
Notes: QuickDASH = shortened version of the DASH (Disabilities of the Arm, Shoulder, and Hand); NPRS = Numeric Pain Rating Scale
The following continuous variables were converted to categories: Age – <45 y, 45–65 y, and >65 y; Symptom Acuity – Acute (0–2 weeks), Sub-Acute (3–11 weeks), and Chronic (≥12 weeks); Medication for Condition – None, and 1 or More; Number of Comorbid Conditions – None, 1, 2 or 3, and 4 or More.
Patients’ conditions were recorded via MDT classification schema (95% CI). The provisional classification of 77.8% (66.7, 88.9), 78.0% (65.4, 90.7), and 55.0% (33.2, 76.8) of patients’ conditions did not change at follow-up for the Shoulder Derangement, Shoulder Dysfunction, and Other classifications, respectively. The Shoulder Derangement classification was most likely to change to Shoulder Dysfunction (18.5% of time; 8.2, 28.9), the Shoulder Dysfunction category was most likely to change to Other (12.2% of the time; 2.2, 22.2), and the Other group was most likely to change to Shoulder Derangement (25.0% of the time; 6.0, 43.9). Fewer patients were found in the Shoulder Articular Dysfunction and Shoulder Contractile Dysfunction classifications; consequently, these two subcategories were merged into the overall Shoulder Dysfunction classification. None of the patients’ conditions were classified as Posture. Totally, 44.3% (35.3, 53.4) of patients’ conditions were classified as Shoulder Derangement, 40.0% (31.0, 48.9) of patients’ conditions were classified as Shoulder Dysfunction, 0.0% of patients’ conditions were classified as Posture, and 15.6% (9.0, 22.3) of patients conditions were classified as Other (Table 2).
Table 2.
Prevalence of MDT Classifications (n = 115).
| MDT Classification | Count | Percent |
|---|---|---|
| Shoulder Derangement | 51 | 44.3 (35.3, 53.4) |
| Shoulder Dysfunction | 46 | 40.0 (31.0, 48.9) |
| Shoulder Articular Dysfunction | 26 | 22.6 (14.9,30.2) |
| Shoulder Contractile Dysfunction | 20 | 17.4 (10.4,24.3) |
| Posture | 0 | 0.0 (0) |
| Other | 18 | 15.6 (9.0, 22.3) |
MDT = Mechanical Diagnosis and Therapy; the overall Shoulder Dysfunction classification is comprised of two sub-classifications, Shoulder Contractile Dysfunction and Shoulder Articular Dysfunction
(95% confidence interval)
The interaction between MDT classification at intake and clinical outcomes (i.e. QuickDASH score, NPRS score, and duration of care) at discharge was analyzed. Posture was excluded from the analysis as no patients’ conditions were classified in this category. The primary analysis included Shoulder Derangement, Shoulder Dysfunction, and Other classifications. Difference scores were calculated, or the difference between the clinical outcome measures (i.e. disability or pain intensity) at intake and discharge (Table 3). For the NPRS analysis, all groups managed via MDT methods made clinically significant improvements in pain intensity at discharge. A statistically significant difference was observed between the Shoulder Derangement and Shoulder Dysfunction classifications (p = 0.01); the difference was also clinically significant based on an estimated between-group difference of 40% of the MCID (40% of 2.17 = 0.87; between-group difference score = 1.4) [33]. For the QuickDASH analysis, all groups managed via MDT methods made clinically significant improvements in disability at discharge. No statistically significant differences between the groups existed (p = 0.87). For the duration of care analysis, the average time to discharge for patients classified as Shoulder Derangement, Shoulder Dysfunction, and Other was 28.4 days (range = 1–85, SD = 20.9), 63.7 (range = 7– 180, SD = 40.6), and 56.7 (range = 8–158, SD = 46.7), respectively. A statistically significant difference was observed between the Shoulder Derangement and Shoulder Dysfunction (p = 0.00; between-group difference = 35.3 days) and Shoulder Derangement and Other subgroups (p = 0.00; between-group difference = 28.3 days).
Table 3.
Disability and pain comparison by MDT classification (n = 115).
| Shoulder Derangement | Shoulder Dysfunction | Other | p-value | |
|---|---|---|---|---|
| Mean QuickDASH at Intake | 29.1 | 36.6 | 45.0 | |
| Mean QuickDASH at Discharge | 10.7 | 17.9 | 28.8 | |
| Mean Difference Score | 18.4 | 18.7 | 16.2 | p = 0.87 |
| Mean NPRS at Intake | 4.8 | 4.6 | 6.5 | |
| Mean NPRS at Discharge | 1.0 | 2.2 | 2.6 | |
| Mean Difference Score | 3.8 | 2.4 | 3.9 | p = 0.03 |
MDT = Mechanical Diagnosis and Therapy; QuickDASH = shortened version of the DASH (Disabilities of the Arm, Shoulder, and Hand); NPRS = Numeric Pain Rating Scale
The Mean Difference Score was calculated by subtracting the mean change in the intake outcome measure (i.e. the QuickDASH or NPRS) from the mean change in the discharge measure (intake mean change minus discharge mean change = Mean Difference Score)
Discussion
The primary findings in this investigation were that (1) 44.3% (35.3, 53.4), 40.0% (31.0, 48.9), and 15.6% (9.0, 22.3) of patients’ conditions were classified as Shoulder Derangement, Shoulder Dysfunction, and Other, respectively, (2) all groups managed via MDT methods made clinically significant improvements in disability and pain intensity at discharge, (3) a statistically significant difference in pain intensity at discharge was observed between the Shoulder Derangement and the Shoulder Dysfunction classifications (p = 0.01), and (4) patients with the Shoulder Derangement classification were discharged, on average, 35.3 days earlier than the Shoulder Dysfunction classification and 28.3 days earlier than the Other classification.
Consistent with the first hypothesis, the most prevalent classification was Shoulder Derangement at 44.3% (35.3, 53.4). This finding is consistent with data presented by May and Rosedale (42.5% prevalence of Shoulder Derangement) [27] and is higher than data presented by Heidar Abady et al (37.6% prevalence of Shoulder Derangement) [26]. The slightly lower prevalence of Shoulder Derangement reported by Heidar Abady et al [26] may be explained by the methodological approach; the study included 93 patients with shoulder pain and 27 patients were classified as having a Spinal classification. Including patients with a Spinal classification may have diluted the sample resulting in an overall lower Shoulder Derangement prevalence. This investigation chose to exclude these patients from entering the study. Interestingly, the patients in the current investigation were slightly older and had a higher percentage of chronic symptoms compared to the study by Heidar Abady [26], which is contrary to MDT spine research findings; the prevalence of Derangement syndrome in the spine generally increases as symptom duration and age decrease [34]. Further studies across varying geographical locations and patient demographics are needed to confirm these data.
The Shoulder Derangement classification exhibited a statistically significant difference in pain intensity (p = 0.01) compared to the Shoulder Dysfunction classification. Clinically important group differences have been estimated to be 40% of the MCID [33], thus the difference was also considered clinically significant based on this reference standard (40% of the NPRS MCID = 0.87; between-group NPRS difference score = 1.4). No statistically or clinically significant differences were exhibited between any groups for disability outcomes. These findings could be explained by the theoretical cause of and subsequent management approaches for the Shoulder Derangement and Shoulder Dysfunction syndrome. The Shoulder Derangement syndrome is theorized to result from intra-articular inclusions which obstruct and make joint movement painful and limited. The Shoulder Dysfunction syndrome is thought to result from adaptively shortened scar tissue in the periarticular tissues (e.g. shoulder tendons, ligaments, and/or joint capsule) [13,35]. The inclusions associated with the Shoulder Derangement syndrome can release and manifest clinically as rapid improvements in symptoms and ROM upon application of movement strategies. The impaired periarticular tissue in the Shoulder Dysfunction syndrome causes intermittent pain that does not rapidly change upon loading of structurally impaired tissue. Based on these models, changes in pain and disability outcomes could be expected to occur relatively slowly and gradually in the Shoulder Dysfunction classification. The findings from the duration of care analysis further support this theoretical model and is also consistent with the third hypothesis; the Shoulder Derangement classification had the shortest duration of care (the Shoulder Derangement classification was discharged 35.3 days earlier than the Shoulder Dysfunction classification) and showed a statistically significant difference relative to the Shoulder Dysfunction classification (p = 0.00). Differences observed in the duration of care analysis could be explained by the practice patterns of MDT clinicians when managing patients affected by Shoulder Dysfunction. MDT clinicians tend to increase the amount of time between visits once the Shoulder Dysfunction classification has been confirmed because, ultimately, the intervention is entirely patient-driven and the shoulder improvements are expected to occur gradually with the application of regular home exercise. Follow-up appointments (generally every few weeks) are reserved for ensuring the condition is improving as expected or for altering the intervention in the event of any unintended consequences, such as the condition reaching a plateau or worsening. It is not uncommon to discharge a patient prior to complete resolution of the Shoulder Dysfunction if the patient has a good understanding of self-management, recovery of full function, and prophylaxis [13]. Further studies should consider measuring pain and disability outcomes over several periods, including less than 7 day, 14 day, discharge, and 6-month follow-up for patients with shoulder disorders classified via MDT syndromes. Detailed shoulder interventions should be recorded to help expose meaningful and generalizable differences in clinician practice patterns relative to MDT classification.
The Other classification (15.6% prevalence) had the highest pain and disability outcomes at discharge (Mean NPRS at Discharge = 2.6; Mean QuickDASH at Discharge = 28.8). Conditions included in this category are wide-ranging (Appendix) and may represent a spectrum of pathology that is more resistant to physical therapy intervention. The MDT interventions for this important classification are less well-defined relative to the Derangement, Dysfunction, and Posture classifications [13]. To the best of the author’s knowledge, this investigation is the first study to analyze outcomes relative to the Other classification for the shoulder. Further studies are needed to understand the clinical profiles and management strategies for patients affected by the conditions in these subgroups.
This study has several important limitations to consider. Detailed interventions during the study period were not recorded; however, clinicians were trained to deliver matched interventions according to the MDT classification. Individually tailored end-range, repeated, and/or sustained movements guided by symptomatic and mechanical responses have been associated with rapid improvement and superior outcomes compared to generic exercise programs [36], which could explain why all groups in this investigation exceeded the MCID for pain and disability outcomes. However, this study design precludes us from determining if differences in outcomes are attributed to the prognostic value of the system, the treatments performed, or a combination. Future studies are needed to determine whether classification via MDT relative to other orthopedic approaches results in superior clinical, humanistic, and economic outcomes for patients with shoulder challenges.
The results of this investigation may not be generalizable to clinicians without advanced training in MDT. Clinicians in this study had high levels of training in MDT (all clinicians were certified in MDT and four clinicians held their diploma in MDT). To become certified in MDT, one must complete 108 h of post-graduate coursework related to musculoskeletal care and MDT principles for spine and extremity condition management and the successful passing of a standardized written and practical examination. The highest level of training in the International McKenzie Institute, the diploma in MDT, requires the completion of 360 h of both a didactic and clinical component as well as the successful passing of an oral examination. It is unknown if the findings in this study would be comparable for clinicians with minimal or no training in MDT. Future studies need to be conducted in this regard and others are encouraged to replicate this type of investigation and test the external validity by examining shoulder outcomes amongst clinicians with varying levels of MDT training.
Conclusion
The findings of this prospective cohort study indicate that (1) 44.3% (35.3, 53.4), 40.0% (31.0, 48.9), and 15.6% (9.0, 22.3) of patients’ conditions were classified as Shoulder Derangement, Shoulder Dysfunction, and Other, respectively, (2) all groups managed via MDT methods made clinically significant improvements in disability and pain intensity at discharge, (3) a statistically significant difference in pain intensity at discharge was observed between the Shoulder Derangement and the Shoulder Dysfunction classifications (p = 0.01), and (4) patients with the Shoulder Derangement classification were discharged, on average, 35.3 days earlier than the Shoulder Dysfunction classification and 28.3 days earlier than the Other classification. This study helps verify previous work and adds further insight into the classification of shoulder challenges via MDT methods.
Biography
Richard Yarznbowicz obtained his doctor of physical therapy from the University of the Sciences in Philadelphia in 2010 before earning his diploma in Mechanical Diagnosis and Therapy in 2013. He is also a board certified Orthopedic Clinical Specialist. He has authored and co-authored several publications regarding the assessment and treatment of patients with musculoskeletal disorders.
Appendix
Appendix.
MDT extremity other subgroups.
| Serious pathology (list is not exhaustive) | |||
|---|---|---|---|
| Category | Clinical findings (Red Flags) | Clinical Examples | |
| Cancer | Age >55, history of cancer, unexplained weight loss, progressive, not relieved by rest | May be primary site or metastases | |
| Fracture | History of significant trauma (If osteoporosis present; minor trauma) Loss of function. All movements make worse. |
||
| Infection |
Fever, malaise, constant pain, all movements worsen |
|
|
|
Subgroup |
Definition |
Criteria |
Clinical Examples |
| Chronic Pain Syndrome | Pain-generating mechanism influenced by psychosocial factors or neurophysiological changes | Persistent widespread pain, aggravation with all activity, disproportionate pain response to mechanical stimuli, inappropriate beliefs and attitudes about pain | Regional pain syndromes |
| Inflammatory | Inflammatory arthropathy | Constant pain, morning stiffness, excessive movements exacerbate symptoms | RA, sero-negative arthritis, some stages of OA |
| Mechanically Inconclusive | Unknown musculoskeletal pathology | Derangement, Dysfunction, Postural and subgroups of OTHER excluded Symptoms affected by positions or movements BUT no recognizable pattern identified or inconsistent symptomatic and mechanical responses on loading |
|
| Peripheral Nerve Entrapment | Peripheral nerve entrapment | No spinal symptoms Local paresthesia/anesthesia May have local muscle weakness |
Carpal tunnel syndrome, meralgia paraesthetica, |
| Post-surgery | Presentation relates to recent surgery | Recent surgery and still in post-operative protocol period | |
| Soft Tissue Disease Process | A fibroblastic or degenerative disease process affecting inert soft tissue with unknown or disputed etiology | Each disease process has a unique clinical presentation, natural history and response to a variety of interventions | Frozen shoulder, Dupuytren’s, plantar fascia syndrome |
| Structurally Compromised | Soft tissue and/or bony changes compromising joint integrity | Mechanical symptoms (ROM restricted, clunking, locking, catching) May have sensation of instability Long history of symptoms or history of trauma Irreversible with conservative care |
Late stage OA, dislocation, labral tear, cruciate ligament rupture, irreducible meniscal tear |
| Trauma/Recovering Trauma | Recent trauma associated with onset of symptoms | Recent trauma associated with onset of constant symptoms/recent trauma associated with onset of symptoms, now improving and pain intermittent | |
| Vascular | Symptoms induced by poor blood supply due to pressure increase in a closed anatomical space | Below knee symptoms, predominantly in younger athletes Consistently induced by exercise or activity May have pain and/or paresthesia in field of local cutaneous nerve and local swelling |
Compartment syndrome |
Disclosure statement
No potential conflict of interest was reported by the author.
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