The advent of direct access to physical therapy services in many countries1–4 has largely contributed to the recognition of the physical therapist (PT) as a front-line health-care provider, meaning the PT must make a conclusion about the patient's condition based on findings from their assessment before establishing and carrying out an intervention plan. In Canada, for example, this has lead to making a diagnosis as being one of the essential entry-level PT competencies.5,6

However, there is no consensus across all PT practice domains and contexts regarding the diagnostic concept, i.e., the process, classification system with labels and diagnostic format that should be used. In fact, there has been long standing debate in this area.7–10 The Diagnostic Dialog initiative, which brought together expert clinicians, researchers and educators from the American Physical Therapy Association (APTA) between 2006 and 20167 did advance the discussion somewhat. In the end, the consensus of the expert group was that a pathoanatomical diagnosis is insufficient to guide physical therapy interventions and that PTs should use diagnostic classifications with terms (labels) that reflect their expertise in the movement system.7,11,12 The APTA then created a Movement System Task Force and held a Movement System Summit.7 From that summit arose criteria for naming movement-related conditions that formed the basis of the APTA recommendations for any PT group who wished to develop a diagnostic concept.13

Because these recommendations do not necessarily lead to standardisation of the diagnostic concept that can be applied to all patients in all PT practice domains and contexts, what a PT communicates as their diagnosis remains the clinician's choice. This lack of standardization can lead to a lack of diagnostic clarity and subsequent confusion for the other health care professionals, patients, families, and other stakeholders who are relying on the PT's diagnosis for the patient follow-up and clinical management. In addition, the lack of standardization can make it difficult to evaluate the diagnostic competency of a PT student or candidate applying for licensure to practice. To address these issues, the physical therapy licensing body in Quebec, the Ordre professionnel de la physiothérapie du Québec (OPPQ), tasked Professor Luc J Hébert, to chair a committee whose objective was to propose a standardized physical therapy diagnostic concept (PT-Dx-C) that would consider the APTA criteria, respect the legislation under which Quebec PTs practice and be universally applicable to all patients, across all PT practice domains and contexts. This paper describes the PT-Dx-C developed by the committee.

The committee members were nine licenced PTs with clinical, academic and research experience in various area of physical therapy practice.

A scoping type review of the white and grey literature (1986–2022) identified existing diagnostic concepts, including classification systems, used within and outside the physical therapy profession. Details on the review strategies are presented in the supplementary material.

Because a significant number of published papers regarding the diagnosis made by PTs that we retrieved were in the form of an invited commentary, conceptual paper or expert group consensus, it was not possible to use a known rating system that would allow one to meaningfully distinguish the quality of the information in one document from another. Therefore, from a first reading, the committee systematically categorized the retrieved documents, into four categories according to the criteria described below using a consensus approach:

• Category 1 –highly contributive to the development of the PT-Dx-C and relevant to all conditions or populations seen by a PT. The documents assigned to this category were those that specifically discussed diagnosis in the context of physical therapy practice with applicability to all conditions or populations seen by a PT. In addition, they were deemed highly contributive to the development of the Pt-Dx-C by all the committee members (9/9) i.e. the documents had to contain original concepts or ideas that were supported by scientific data or strong arguments. These documents were systematically read and analysed by all committee members (9/9).

• Category 2 –moderately contributive to the development of the PT-Dx-C and relevant to all conditions or populations seen by a PT. The criteria for assignment in this category were the same as for category 1 with one exception. Documents assigned to category 2 were those that were not considered highly contributive to the development of the PT-Dx-C by all committee members (<9/9). These documents were systematically read and analysed by two members of the committee.

• Category 3 –highly contributive to the development of the PT-Dx-C but only relevant to a specific condition or subpopulation seen by a PT. The documents assigned to this category were those that specifically discussed a diagnosis in the context of physical therapy practice, but their content was relevant to only a sub-set of conditions or populations seen by a PT. Assignment in this category was decided by a consensus of the committee members. These documents were systematically read and analysed by two committee content experts.

• Category 4 –supplemental documents: The documents assigned to this category were those whose content either did not target any specific condition or population seen by a PT, or whose content was very general with respect to diagnostic classifications. For example, documents in this category might discuss diagnostic concepts not specific to the field of physical therapy. These documents were read and analysed by at least two members of the committee.

Retrieved documents were rejected if they did not meet any of the criteria listed above, that is: they did not contain new ideas or concepts, were not well supported by scientific data or strong arguments, simply replicated or synthetized the content of original papers, did not specifically discuss diagnosis in health professions or were abstracts only.

To facilitate further analyses, each committee member extracted the relevant citations of their respective readings in a standard table and organized them according to specific pre-determined objectives detailed in the supplementary material. Results were summarized during face-to-face meetings with the aim of reaching a common understanding, synthetizing the information, and responding to the objectives of the committee.

The committee held 17 meetings over 40 months. The final report was submitted to the OPPQ in December 2009.14 From 8506 documents found in the two searches, 194 were read in full and categorized by the committee members (category 1, n = 45; category 2, n = 51; category 3, n = 36; category 4, n = 62).

The retained documents typically described classification systems, labels or formats applicable to a subgroup of patients seen by PTs, commonly from the neurological11,15–18 or musculoskeletal19–23 practice domains. Other previously published diagnostic concepts attempted to be universally applicable but had marked limitations. The APTA proposed a classification system of “Preferred Practice Patterns”24 while Gedda25 proposed a classification and labelling system based on impairments of structures and function. However, these concepts have not been adopted because they were complex to assimilate and did not correspond to the way PT manage and treat their patients.

In the majority of documents we reviewed, diagnoses were based on results from standardized assessment of specific movements/tasks15,17,18,20,21,23 and in some cases, from the examination of associated impairments.15,17,23 Diagnostic classification and labels often referred to the movement or associated impairments15,17,21,23 and sometimes to interventions.20,26 The pathoanatomical component, however, was rarely included.22

After reviewing and synthesizing the content of the retained documents, the committee concluded that they could not identify a published diagnostic concept that was applicable to all patients in all physical therapy practice domains and contexts. The committee therefore decided to use the information from the documents to develop the criteria of a new universal PT-Dx-C, which are formulated as follows:

• 1.

  The PT-Dx-C is a process with a classification and labelling structure that uses a specific format: making a diagnosis involves rigorous data collection (structured interview and physical examination), analysis and synthesis that culminates with specific diagnostic labelling in a consistent format.10,24,27–29 The labelling must be in keeping with the commonly accepted meaning of the term diagnosis that is, a statement or conclusion from the assessment30 that identifies the presumed causes or consequences associated with the health problem. Whenever possible, the diagnostic labelling should include the identified health problem and its severity10,29,31,32;

• 2.

  The terms of the PT-Dx-C must be understandable by the healthcare team to facilitate collaborative practice: the diagnostic classification and labelling must use recognizable and operationally defined terms that are mutually exclusive and do not overlap9,10,17,18,29,33,34;

• 3.

  The PT-Dx-C must be flexible enough to evolve according to the advancement of science, the physical therapy profession and society10,34,35;

• 4.

  The PT-Dx-C must be applicable to all patients in all physical therapy practice domains and contexts24,36,37;

• 5.

  The PT-Dx-C must be consistent with evidence-based and best practice9,10,34,38; notably, the patient data that are analysed and synthesized to establish the diagnosis must be collected using tests and measures with appropriate measurement properties;

• 6.

  The PT-Dx-C must include the information needed to determine precautions or contraindications, establish the prognosis, and guide the selection of physical therapy interventions9,17,18,24,25,27,34,35,39–42;

• 7.

  The PT-Dx-C must reflect the whole person at the organic, individual and social level as well as contextual factors and the interaction between these different elements.43 Taking this information into account could substantially modify the diagnostic labelling and therefore, the choice of interventions and establishment of the prognosis.27–29,34,41,44

The diagnosis made by the PT stems from a rigorous process in which the PT organizes, analyses, and synthesizes patient data and then establishes a diagnosis using a standardized classification and labelling format. The diagnosis made by the PT must therefore indicate the patient's health problem and its impacts on functioning as relevant to physical therapy practice in the context of the individual and their contextual factors.

As to the format of the diagnosis made by the PT, the committee proposed the following three distinct components for the PT-Dx-C in the following order:

The health problem is the condition, or illness of the patient labelled using the latest version of the International Classification of Diseases (ICD-11).45 To further describe the health problem, the PT-Dx-C can also include one or more classifications, such as severity (e.g., ligament sprain grade), type (e.g., fracture classification) or stage (ex. stage of osteoporosis). In some contexts, such as in the early stage of a health condition, specificity may not be possible. In this case, it is recommended that the PT categorize using more general terms and proceed accordingly.46A more specific diagnosis may be established later, depending on the course of the condition, which reflects the fact that the diagnosis is really an evolving working hypothesis. The PT can identify certain health problems included in the ICD if the tests required to confirm the health problem are within their scope of practice as defined by the legislation under which they practice. When the tests required to identify and describe the health problem are not within the PT scope of practice, the physician's contribution to the identification of the health problem should be acknowledged in the labelling.

The primary impairment is labelled according to the International Classification of Functioning, Disability and Health (ICF).43 This is a problem with an anatomical structure or an organic function that, according to the PT's clinical reasoning, is the main contributor to the patient's primary activity limitations and participation restrictions. For more specificity, the PT may indicate the level of a given impairment by using the results of a test for which the measurement properties (e.g., metrological qualities) are known and appropriate for this function. The primary impairment should ideally be a treatment-effect mediator,47 which is known to improve in response to an intervention and to correlate with a change in the patient's limitation.

The primary activity limitation or participation restriction, also labelled according to the ICF,43 are, respectively, the main difficulty or difficulties in performing a task or in being involved in a real-life situation that best account for the patient's disability. For more specificity, the PT may indicate the level of a given limitation or restriction by using the results of appropriate tests. It is the PT's decision as to whether to include one or more activity limitations or participation restrictions. This is patient-centred by taking into consideration the patient's values, needs, contextual factors and the relevant results from the PT's assessment.

The committee chose to use the ICD45 and the ICF43 for diagnostic classification and labelling as they use mutually exclusive and jointly exhaustive classification components and labelling which are fundamental properties of a diagnostic classification.34 They are also complementary, and together, sufficient to describe the patient condition and guide physical therapy interventions. The ICD and ICF are also meant to be shared by all health professions to facilitate collaborative practice. Thus, the PT is advised to use ICF terms that correspond to their own scope of practice, as defined in the legislation under which they practice.

The present paper describes the PT-Dx-C, a diagnostic concept that could apply to all patients in all physical therapy practice domains and contexts, as well as the process used to develop it. The choice of a standardized format for the PT-Dx-C as well as ICD and ICF classifications and labelling help to ensure that application of the PT-Dx-C will facilitate communication amongst healthcare professions and other key stakeholders. The process employed to develop the PT-Dx-C as well as the criteria that the PT must use to establish their diagnosis is likely to produce a label that is clinically meaningful and that reflects most accurately the patient's health condition and functioning and therefore, that can guide the PT in the establishment of a prognosis and intervention plan.

The PT-Dx-C is in keeping with APTA recommendations on a diagnosis that emerged after years of discussions.13 The PT-Dx-C uses recognized, movement-related terms (and similar terms for similar movements) and it can be applied to all patients regardless of their health condition, age or context. Moreover, the PT-Dx-C advances the work of Jiandani and Mhatre48 who suggested using the ICD and the ICF for different but complementary diagnostic purposes. They emphasized the importance of knowing the pathoanatomical source of symptoms, as they believed this is necessary to guide the PT to hypothesize the expected impairments and plan the assessment with due precautions or contraindications for diagnosing movement dysfunctions. Finally, they also recommended using the ICF to allow for a clear description of the functional status of the patient in terms of impairments of body structures and function, activity limitations and participation restrictions.30 The PT-Dx-C, however, goes further than the proposition of Jiandani and Mhatre by imposing seven criteria and a standardized format to the diagnostic classifications and labelling, thus helping to ensure that the relevant components of the diagnosis are always in place.

The use of the ICF and ICD labels achieves the primary function of diagnosis, which is to communicate to others the conclusions of the PT's assessment. The use of the ICF provides a universal language and terminology for communication and classification purposes across the health care professions.49 In a few papers published recently,49–51 some have raised concerns about numerous repercussions of creating and using profession-specific diagnostic labels. PT-Dx-C addresses this concern by including the commonly employed interdisciplinary diagnostic labels from the ICD and simply adding movement expertise from the PT's assessment to communicate more information to others as well as to guide the intervention process.

Similar to the PT-Dx-C, previously published diagnostic concepts include the assessment of standardized tasks and underlying impairments. Some movement system-based diagnostic concepts, for example, describe a process in which the diagnosis is established from the observation of specific clusters of movement impairments during the execution of core tasks.11,15,16 Task observation may then generate hypotheses on underlying impairments that once confirmed may guide the intervention plan. The PT-Dx-C also involves a rigorous examination process that includes a systematic observation of tasks. However, in line with the seventh criterion of the PT-Dx-C, the tasks observed are determined primarily according to the patient's specific needs. Additionally, the PT-Dx-C labelling identifies the primary impairment as the major contributor to the patient's primary limitations or restrictions. Thus the PT-Dx-C format and logic can help to facilitate the identification of treatment priorities,52 whether they be aimed at impairments, limitations, restrictions or a combination of these factors.

Movement system-based diagnostic concepts focus on the movement pattern impairments without explicitly noting relationships between the impairments and the patients’ limitations or restrictions.11,15,16,21,23 This is an important shortcoming because not all movement pattern impairments result in important limitations or restrictions and therefore not all movement pattern impairments warrant intervention. One example is the recent evidence-based recommendations for children with cerebral palsy practicing walking on a treadmill to improve walking capacity.53 By focusing on the whole task of walking, movement pattern impairment due to a loss of integrity of certain body function(s) and compensations are acceptable and the walking intervention is manipulated by the PT to ensure that compensations do no harm.

Our concept leaves room for the PT's judgement in establishing their diagnosis, that is, in prioritizing which impairments, activity limitations and participation restrictions are most relevant to the patient's situation at a given point in time. Thus, the PT-Dx-C supports the PT using their expertise in a more holistic manner. With the PT-Dx-C, the PT is not simply an expert in the movement system12,13 but they are an expert in establishing the relationships amongst movement-related impairments, activity limitations and participation restrictions.

The PT-Dx-C is a universal physical therapy diagnostic concept and thus addresses limitations of condition-based (e.g., balance problem, back pain) or practice domain-based (e.g. neurological, musculoskeletal) concepts which can have several terms that describe the same condition depending on the concept used by the PT. For example, for the same health condition, in this case a low back problem, the PT could establish their diagnosis as derangement syndrome using the McKenzie method of Mechanical Diagnosis and Therapy (MDT),20 as symptom modulation approach using the treatment-based classification (TBC)26 or as lumbar flexion syndrome using Movement System Impairment (MSI) syndromes classification.21 This disparity in conceptual models and in the terminology used in each classification makes it difficult to interpret the conclusion of the evaluation made by PTs for people not familiar with the specific concept the PT used.

The PT-Dx-C is a proposed framework that would benefit from further study. One limitation of the PT-Dx-C is that its reliability has not yet been quantitatively evaluated. Furthermore, we do not know if the diagnostic label as established by the PT brings sufficient and relevant information to describe what it purports to describe, that is the patient functioning, which refers to the validity of the PT-Dx-C. Thirdly, further information is needed on how it is used in practice, including barriers and facilitators to its implementation and the extent to which use of the PT-Dx-C facilitates communication and optimal outcomes, be they client- or service-based. The diagnosis that emerges from the PT-Dx-C could also be considered long because it includes the ICD terms to name the pathology or condition. As front-line health-care providers, PTs need to name the patient's health condition because this information dictates precautions and contraindications and facilitates establishing the prognosis and the intervention plan. Movement system-based diagnostic concepts, however, do not necessarily include this information. Alternatively, the diagnostic label can be left as is, without including the health problem component, if this information is known from the PT and accessible in the medical record. The PT-Dx-C is thus a concept that promotes both collaboration between healthcare professionals and the added value that the PT brings to healthcare service provision with their unique expertise and skill beyond identification of the health condition. The supplementary material shows some examples of diagnostic labelling according to the proposed PT-Dx-C.

To provide appropriate physical therapy services, the PT must make a diagnosis. This step is an essential competency for entry into practice, especially given the existence of direct access to physical therapy. The PT-Dx-C is applicable to all patients in all physical therapy practice domains and contexts. While it has a standardized format, it is a pragmatic, flexible, holistic, and collaborative concept that promotes and supports clinical reasoning and judgement. The diagnostic labelling of the PT-Dx-C clearly reflects the PT's expertise in the human movement system and allows for clear communication of the PT's conclusions in a way that can be understood by others.