Effect of Adding McKenzie Syndrome, Centralization, Directional Preference, and Psychosocial Classification Variables to a Risk-Adjusted Model Predicting Functional Status Outcomes for Patients With Lumbar Impairments.

Study Design Retrospective cohort. Background Patient-classification subgroupings may be important prognostic factors explaining outcomes. Objectives To determine effects of adding classification variables (McKenzie syndrome and pain patterns, including centralization and directional preference; Symptom Checklist Back Pain Prediction Model [SCL BPPM]; and the Fear-Avoidance Beliefs Questionnaire subscales of work and physical activity) to a baseline risk-adjusted model predicting functional status (FS) outcomes. Methods Consecutive patients completed a battery of questionnaires that gathered information on 11 risk-adjustment variables. Physical therapists trained in Mechanical Diagnosis and Therapy methods classified each patient by McKenzie syndromes and pain pattern. Functional status was assessed at discharge by patient-reported outcomes. Only patients with complete data were included. Risk of selection bias was assessed. Prediction of discharge FS was assessed using linear stepwise regression models, allowing 13 variables to enter the model. Significant variables were retained in subsequent models. Model power (R(2)) and beta coefficients for model variables were estimated. Results Two thousand sixty-six patients with lumbar impairments were evaluated. Of those, 994 (48%), 10 (<1%), and 601 (29%) were excluded due to incomplete psychosocial data, McKenzie classification data, and missing FS at discharge, respectively. The final sample for analyses was 723 (35%). Overall R(2) for the baseline prediction FS model was 0.40. Adding classification variables to the baseline model did not result in significant increases in R(2). McKenzie syndrome or pain pattern explained 2.8% and 3.0% of the variance, respectively. When pain pattern and SCL BPPM were added simultaneously, overall model R(2) increased to 0.44. Although none of these increases in R(2) were significant, some classification variables were stronger predictors compared with some other variables included in the baseline model. Conclusion The small added prognostic capabilities identified when combining McKenzie or pain-pattern classifications with the SCL BPPM classification did not significantly improve prediction of FS outcomes in this study. Additional research is warranted to investigate the importance of classification variables compared with those used in the baseline model to maximize predictive power. Level of Evidence Prognosis, level 4. J Orthop Sports Phys Ther 2016;46(9):726-741. Epub 31 Jul 2016. doi:10.2519/jospt.2016.6266.

McKenzie lumbar classification: inter-rater agreement by physical therapists with different levels of formal McKenzie postgraduate training.

STUDY DESIGN: Inter-rater chance-corrected agreement study. OBJECTIVE: The aim was to examine the association between therapists' level of formal precredential McKenzie postgraduate training and agreement on the following McKenzie classification variables for patients with low back pain: main McKenzie syndromes, presence of lateral shift, derangement reducibility, directional preference, and centralization. SUMMARY OF BACKGROUND DATA: Minimal level of McKenzie postgraduate training needed to achieve acceptable agreement of McKenzie classification system is unknown. METHODS: Raters (N = 47) completed multiple sets of 2 independent successive examinations at 3 different stages of McKenzie postgraduate training (levels parts A and B, part C, and part D). Agreement was assessed with κ coefficients and associated 95% confidence intervals. A minimum κ threshold of 0.60 was used as a predetermined criterion for level of agreement acceptable for clinical use. RESULTS: Raters examined 1662 patients (mean age = 51 ± 15; range, 18-91; females, 57%). Data distributions were not even and were highly skewed for all classification variables. No training level studied had acceptable agreement for any McKenzie classification variable. Agreements for all levels of McKenzie postgraduate training were higher than expected by chance for most of the classification variables except parts A and B training level for judging lateral shift and centralization and part D training level for judging reducibility. Agreement between training levels parts A and B, part C, and part D were similar with overlapping 95% confidence intervals. CONCLUSION: Results indicate that level of inter-rater chance-corrected agreement of McKenzie classification system was not acceptable for therapists at any level of formal McKenzie postgraduate training. This finding raises concerns about the clinical utility of the McKenzie classification system at these training levels. Additional studies are needed to assess agreement levels for therapists who receive additional training or experience at the McKenzie credentialed or diploma levels. LEVEL OF EVIDENCE: 2.

Association between centralization and directional preference and functional and pain outcomes in patients with neck pain.

STUDY DESIGN: Retrospective cohort. OBJECTIVES: In subjects with neck pain, the present study aimed (1) to describe the prevalence of centralization (CEN), noncentralization (non-CEN), directional preference (DP), and no directional preference (no DP); (2) to determine if age, sex, fear-avoidance beliefs about physical activity, number of comorbid conditions, or symptom duration varies among subjects who demonstrate CEN versus non-CEN and DP versus no DP; and (3) to determine if CEN and/or DP are associated with changes in function and pain. BACKGROUND: CEN and DP are prevalent among patients with low back pain and should be considered when determining treatment strategies and predicting outcomes; however, these findings are not well investigated in patients with neck pain. METHODS: Three hundred four subjects contributed data. CEN and DP prevalence were calculated, as was the association between CEN and DP, and age, sex, number of comorbid conditions, fear-avoidance beliefs, and symptom duration. Multivariate models assessed whether CEN and DP predicted change in function and pain. RESULTS: CEN and DP prevalence were 0.4 and 0.7, respectively. Younger subjects and those with fewer comorbid conditions were more likely to centralize; however, subjects who demonstrated DP were more likely to have acute symptoms. Subjects who centralized experienced, on average, a 3.6-point (95% confidence interval: -0.3, 7.4) improvement in function scores, whereas subjects with a DP averaged a 5.4-point (95% confidence interval: 0.8, 10.0) improvement. Neither CEN nor DP was associated with pain outcomes. CONCLUSION: DP and, to a lesser extent, CEN represent evaluation categories that are associated with improvements in functional outcomes.

Association between directional preference and centralization in patients with low back pain.

STUDY DESIGN: Prospective, longitudinal, observational cohort. OBJECTIVES: Primary aims were to determine (1) baseline prevalence of directional preference (DP) or no directional preference (no-DP) observed for patients with low back pain whose symptoms centralized (CEN), did not centralize (non-CEN), or could not be classified (NC), and (2) to determine if classifying patients at intake by DP or no-DP combined with CEN, non-CEN, or NC predicted functional status and pain intensity at discharge from rehabilitation. BACKGROUND: Although evidence suggests that patient response classification criteria DP or CEN improve outcomes, previous studies did not delineate relations between DP and CEN findings and outcomes. METHODS: Eight therapists classified patients using standardized definitions for DP and CEN. Prevalence rates for DP and no-DP and CEN,non-CEN, and NC were calculated. Ordinary least-squares multivariate regression models assessed whether multilevel classification combining DP and CEN (DP/CEN, DP/non-CEN, DP/NC, no-DP/non-CEN, and no-DP/NC categories) predicted discharge functional status (scale range, 0 to 100, with higher values representing better function) or pain intensity (scale range, 0 to 10, with higher values representing more pain). RESULTS: Overall prevalence of DP and CEN was 60% and 41%, respectively. For those with DP, prevalence rates for DP/CEN, DP/non-CEN, and DP/NC were 65%, 27%, and 8%, respectively. The amount of variance explained (R2 values) for function and pain models was 0.50 and 0.39, respectively. Compared to patients classified as DP/CEN, patients classified as DP/non-CEN or no-DP/non-CEN reported 7.7 and 11.6 functional status units less at discharge (P<.001), respectively, and patients classified as no-DP/non-CEN reported 1.7 pain units more at discharge (P<.001). CONCLUSIONS: Findings suggest that classification by pain pattern and DP can improve a therapist's ability to provide a short-term prognosis for function and pain outcomes. LEVEL OF EVIDENCE: Prognosis, level 1b-.

Prevalence of classification methods for patients with lumbar impairments using the McKenzie syndromes, pain pattern, manipulation, and stabilization clinical prediction rules.

OBJECTIVES: Aims were (1) to determine the proportion of patients with lumbar impairments who could be classified at intake by McKenzie syndromes (McK) and pain pattern classification (PPCs) using Mechanical Diagnosis and Therapy (MDT) assessment methods, manipulation, and stabilization clinical prediction rules (CPRs) and (2) for each Man CPR or Stab CPR category, determine classification prevalence rates using McK and PPC. METHODS: Eight physical therapists practicing in eight diverse clinical settings classified patients typically referred to rehabilitation by McKenzie syndromes (i.e. derangement, dysfunction, posture, or other), pain pattern classification [i.e. centralization (CEN), not centralization (Non CEN), and not classified (NC)], Manipulation CPR (positive, negative), and stabilization CPR (positive, negative). Prevalence rates with 95% confidence intervals (CI) were calculated for each classification category by McK, PPC, and manipulation and stabilization CPRs. Prevalence rates (95% CIs) for McK and PPC were calculated for each CPR category separately. RESULTS: Data from 628 adults [mean age: 52±17 years, 56% female] were analyzed. Prevalence rates were: McK - derangement 67%, dysfunction 5%, posture 0%, other 28%; PPC - CEN 43%, Non CEN 39%, NC 18%; manipulation CPR - positive 13%; Stab CPR - positive 7%. For patients positive for manipulation CPR (n = 79), prevalence rates for derangement were 89% and CEN 68%. For patients positive for stabilization CPR (n = 41), prevalence rates for derangement were 83% and CEN 80%. DISCUSSION: The majority of patients classified based on initial clinical presentation by manipulation and stabilization CPRs were also classified as derangements whose symptoms centralized. Manipulation and stabilization CPRs may not represent a mutually exclusive treatment subgroup but may include patients who can be initially treated using a different classification method.