Patellar tendinosis, frequently included in the contemporary spectrum of patellar tendinopathy, constitutes a musculoskeletal condition of high clinical relevance, especially in athletes subjected to repetitive loads of jumping, deceleration, and changes in direction. Although historically described in association with “jumper’s knee,” the current understanding goes beyond an exclusively sports-related perspective and recognizes a more complex biological, mechanical, and functional picture.

In this context, diagnostic systematization through classifications has come to play a central role, especially when seeking to correlate symptoms, structural changes, and therapeutic options. Among these proposals, the Popkin-Goldman Classification has gained prominence for linking clinical and imaging findings to practical management decisions (POPKIN; GOLDMAN, 2016; GOLMAN et al., 2020; THEODOROU; KOMNOS; HANTES, 2023; MILLAR et al., 2021).

The modern understanding of tendinopathy is based on the idea that pain and tendon dysfunction do not result solely from acute inflammation, but from progressive changes in the extracellular matrix, collagen turnover, cellular response, and tissue mechanics. This conceptual shift was essential for clinical classifications to move beyond being merely descriptive and to begin guiding prognosis and management.

Thus, the relevance of the Popkin-Golman Classification lies precisely in its ability to translate the biological and structural heterogeneity of patellar lesions into categories useful for clinical practice. This perspective aligns with advances in the contemporary pathophysiology of tendinopathy and the need for individualized interventions (SCOTT; BACKMAN; SPEED, 2015; MILLAR; MURRELL; MCINNES, 2017; LOIACONO et al., 2019; MILLAR et al., 2021).

From an epidemiological perspective, patellar tendinopathy has a high prevalence in sports that involve excessive knee extension, such as basketball, volleyball, and soccer. However, the frequency of the condition in non-athletic populations, or in individuals exposed to repetitive occupational and recreational loads, reinforces that this is a broader clinical problem than traditionally assumed. This wide population distribution makes the existence of classification systems capable of distinguishing severity, extent, and likely response to therapeutic intervention even more important. In this context, the Popkin-Golman model emerges as a clinically promising stratification tool (NUTARELLI et al., 2023; ALBERS et al., 2016; RIEL et al., 2019; THEODOROU; KOMNOS; HANTES, 2023).

Historically, the study of anterior knee pain associated with the patellar tendon has been marked by classifications based predominantly on symptoms, sports limitation, and the presence of pain during or after physical activity. As knowledge in sports medicine has matured, it has become evident that exclusively symptomatic systems did not adequately capture the complexity of intratendinous changes and partial ruptures. It was within this environment of conceptual transition that Popkin and Goldman’s proposal gained relevance, emphasizing the need for an integrated approach combining clinical assessment, physical examination, and imaging methods. Subsequently, the reformulation presented by Goldman and colleagues further developed this classification logic, particularly in the field of partial patellar tendon injuries (POPKIN; GOLDMAN, 2016; GOLMAN et al., 2020; FIGUEROA; FIGUEROA; CALVO, 2016; CHALLOUMAS et al., 2021).

The definition of the Popkin-Golman Classification (TABLE 1) can be understood as an attempt to organize patellar tendinopathy and partial ruptures of the patellar tendon into categories with anatomical and therapeutic significance.

Table 1 – Popkin-Golman Classification based on magnetic resonance imaging

Source: GOLMAN et al. (2020).

Figure 1 presents an MRI evaluation of the patellar tendon, along with the standardization of the morphometric measurements used in the analysis of lesions. Panels A–C show examples of structural changes in the tendon, evidenced by areas of increased signal intensity and fiber discontinuity, consistent with varying degrees of tendinosis and partial rupture. Panels D–F, on the other hand, illustrate the main parameters used in measuring lesions, including tendon length, width, and thickness, as well as the dimensions of the injured area and its anatomical location (anterior/posterior and medial/lateral). This integrated approach combining imaging findings and quantitative analysis allows for a more precise assessment of the extent of the injury, directly contributing to the stratification of severity and the clinical application of the Popkin- Golman classification.

Figure 1 – Magnetic resonance imaging evaluation and morphometric parameters of patellar tendon injury

Legend: The Popkin-Golman classification system. Representative MRI image of the patellar tendon with the proposed classification for PPTT. A partial tear was defined by two criteria:

(1) signal change on fluid-sensitive sequences, with a signal in the tendon of intensity equivalent to that of synovial fluid, and (2) morphological defect with evidence of rupture or discontinuity of the fibers on (A) sagittal axial MRI or (B, C) axial MRI. The arrows and long dashed line indicate PPTT, and the short dashed line indicates the cross-section of the tendon. (D: 1, 4). Length dimensions were measured using sagittal MRI images that maximally displayed each dimension. (E: 2, 3, 5, 6) Width and thickness dimensions were measured in the axial view. (F) The exact location of the partial rupture was determined by dividing the axial view (from anterior to posterior) into 9 sections. MRI, magnetic resonance imaging; PPTT, partial patellar tendon tear. Source: GOLMAN et al. (2020)

Unlike older models, this proposal is not limited to pain intensity but emphasizes the topography of the injury, structural compromise, and correlation with imaging, particularly magnetic resonance imaging. This approach facilitates the distinction between cases of reactive overload, focal degeneration, and situations of more advanced partial damage, with a direct impact on the treatment algorithm. It is, therefore, a classification with a translational focus, that is, designed for clinical practice ( ; GOLDMAN, 2016; GOLMAN et al., 2020; DOCKING; OOI; CONNELL, 2015; DESAI et al., 2022).

When discussing the clinical applicability of the Popkin-Golman Classification, it is essential to recognize that the treatment of patellar tendinosis increasingly depends on stratification. In many patients, the same complaint of pain localized at the inferior pole of the patella may correspond to quite distinct biological and structural stages. Therefore, the classification helps reduce diagnostic uncertainty, allowing the clinician to better differentiate cases with the potential to respond to conservative treatment from those in which extensive or refractory partial lesions require therapeutic escalation.

This clinical utility has been reinforced by recent reviews on the diagnosis, therapeutic exercise, and surgery of patellar tendinopathy (POPKIN; GOLDMAN, 2016; MUELLER et al., 2025; LIM;  WONG, 2018;NÚÑEZ-MARTÍNEZ; GUILLEN, 2021).

The historical trajectory culminating in the Popkin-Golman Classification also parallels the shift in terminology within the field of tendon injuries. The gradual replacement of the term “tendinitis” with “tendinopathy” or “tendinosis” reflects the recognition that the degenerative component, fibrillar disorganization, and matrix alterations often outweigh the classic inflammatory component. In this sense, classifying the condition now requires more refined criteria than the simple presence of pain on palpation. The Popkin- Golman proposal directly addresses this epistemological shift, offering a framework more compatible with current knowledge about the diseased tendon (SCOTT; BACKMAN; SPEED, 2015; DAKIN et al., 2015; MILLAR; MURRELL; MCINNES, 2017; LOIACONO et al., 2019).

Figure 2 presents the Popkin-Golman + Blazina classification applied to patellar tendinopathy, integrating MRI findings in axial and magnified views with the stratification of lesion severity. Progression is observed from Grade 1, characterized by the absence of rupture and the presence of tendinosis with preserved thickness, to Grade 4, in which there is an extensive partial rupture exceeding 50% of the tendon’s thickness. The enlarged images allow for detailed visualization of areas of degeneration and fibrillar discontinuity. Furthermore, the figure establishes a correlation with the Blazina classification and presents progressive therapeutic options according to severity, ranging from conservative measures such as physical therapy with eccentric strengthening and the use of anti-inflammatory medications to interventional and surgical approaches in more advanced cases. Thus, the figure provides an integrated summary of the diagnostic and therapeutic aspects of contributing to evidence-based clinical decision-making.

Figure 2 – Popkin-Golman + Blazina classification for patellar tendinopathy: correlation with magnetic resonance imaging and therapeutic options

Legend:Popkin-Golman classification system. Representative magnetic resonance imaging of the patellar tendon with the proposed PPTT classification scheme. The middle column is an enlarged axial section, with the patellar tendon highlighted in white and the PPTT highlighted in yellow. The final column shows the Blazina classification correspondence, with the possible treatment options currently available for each Popkin-Golman grade. AP, anteroposterior; MRI, magnetic resonance imaging; PPTT, partial patellar tendon tear. Source: GOLMAN et al. (2020).

The relationship between symptoms and structure, however, is not linear in patellar tendinopathy, and this is one of the main challenges that justify more robust classifications. There are individuals with significant changes on MRI who present with mild pain, while others have significant functional limitation with less pronounced morphological changes. The Popkin-Golman Classification is useful precisely because it seeks to bridge this gap between anatomy and clinical presentation by incorporating structural severity into therapeutic reasoning. In this way, it helps prevent both undertreatment and excessive interventions in less complex situations (DOCKING; OOI; CONNELL, 2015; ARAÚJO, 2020; ARAÚJO et al., 2025; GOLMAN et al., 2020).

Objectives General Objective

To analyze, through a systematic review of the scientific literature, the Popkin-Golman classification applied to patellar tendinosis, evaluating its clinical applicability, conceptual foundations, and therapeutic implications, as well as its utility in stratifying the severity of the injury, guiding clinical management, and informing therapeutic decision-making in patients with patellar tendinopathy. Specific Objectives

• To describe the conceptual foundations and historical development of the Popkin-Golman classification, contextualizing its creation within the advancement of knowledge regarding patellar tendinopathy.
• To identify and analyze studies in the scientific literature that address the Popkin-Golman classification, highlighting its use in clinical research, reviews, and observational studies.
• To evaluate the clinical applicability of the Popkin-Golman classification, particularly in the stratification of the severity of patellar tendon injuries and the correlation between clinical, structural, and imaging findings.
• To investigate the relationship between the stages of the Popkin-Golman classification and the therapeutic strategies employed, including conservative treatment, physical therapy rehabilitation, and surgical interventions.
• To compare the Popkin-Golman classification with other classification systems for patellar tendinopathy, such as symptom-based clinical models and image-based structural classifications.
• To analyze the therapeutic implications arising from the stratification proposed by the classification, particularly in guiding clinical management and determining prognosis.
• To identify gaps in scientific knowledge related to the use of the Popkin-Golman classification, highlighting methodological limitations and opportunities for future research.

Methodology Study Design

This study consists of a systematic literature review conducted to analyze the clinical applicability and therapeutic implications of the Popkin-Golman Classification in patellar tendinosis.

The process of searching for, selecting, and synthesizing studies was carried out following the methodological recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), widely used to ensure transparency and reproducibility in systematic reviews.

The review was developed through sequential steps that included defining the research question, designing the search strategy, selecting studies, extracting data, and conducting a qualitative analysis of the evidence available in the scientific literature.

PICOS Strategy

The research question was structured using the PICOS strategy (Population, Intervention, Comparison, Outcomes, Study design), as described below:

Population (P):

• Patients diagnosed with patellar tendinopathy or tendinosis, including athletes and the general population.

Intervention (I):

• Application or use of the Popkin-Golman Classification for clinical evaluation, diagnosis, or therapeutic decision-making.

Comparison (C):

• Other classification systems for patellar tendinopathy or the absence of a structured classification.

Outcomes (O):

• Clinical applicability of the classification, correlation with clinical and imaging findings, therapeutic guidance, and impact on conservative or surgical management.

Study design (S):

Observational studies, systematic reviews, clinical trials, cohort studies, cross-sectional studies, and descriptive studies related to patellar tendinopathy and its classification.

Search strategy

The literature search was conducted in widely recognized international scientific databases in the health field:

• PubMed/MEDLINE
• Scopus
• Web of Science
• Embase
• Cochrane Library
• Google Scholar (for supplementary literature) Controlled descriptors and free-text terms were used in combination with Boolean operators.

Main descriptors used

In English

• Patellar tendinopathy
• Patellar tendinosis
• Jumper's knee
• Patellar tendon injury
• Popkin-Golman classification
• Patellar tendon classification
• Patellar tendon tear
• Patellar tendon rupture

2. Screening:

Titles and abstracts were analyzed to verify thematic relevance.

3. Eligibility:

The selected articles were evaluated in full to confirm the inclusion criteria.

4. Inclusion:

Only studies that fully met the methodological criteria were included in the final analysis.

Example search strategy (PubMed)

("patellar tendinopathy" OR "patellar tendinosis" OR "jumper's knee")

AND

("patellar tendon classification" OR "Popkin-Golman classification" OR "patellar tendon tear classification") AND

("clinical management" OR "treatment" OR "diagnosis")

Search period

Studies published between January 2015 and March 2025 were included; this period was chosen because it encompasses contemporary literature related to the pathophysiology of tendinopathy and advances in clinical and therapeutic classifications.

Inclusion criteria

Studies that met the following criteria were included in the review:

• Scientific articles published between 2015 and 2025
• Studies published in English, Portuguese, or Spanish
• Studies involving patellar tendinopathy or tendinosis
• Studies addressing the classification of patellar tendon injuries
• Studies discussing clinical applicability or therapeutic implications
• Relevant systematic reviews, clinical trials, observational studies, or narrative reviews

Exclusion criteria

The following were excluded from the review:

• Duplicate articles across databases
• Studies published before 2015
• Articles without full text available
• Studies addressing knee ligament injuries unrelated to the patellar tendon, other injuries of the extensor mechanism that are not exclusively isolated patellar tendon injuries: Quadriceps injuries; Retinaculum injuries; Patellar injuries (including fracture)
• Isolated case reports without relevant clinical discussion
• Articles not directly related to the classification or management of patellar tendinopathy

Study selection process

The selection of articles took place in three sequential stages, in accordance with the PRISMA guidelines:

1.  Identification:

Studies were identified in the databases using the search strategy.

The selection was performed independently by the reviewers, with any discrepancies resolved by consensus.

Data extraction

For each included study, the following information was collected:

• • Author and year of publication
  • Study type
  • Study population
  • Study objective
  • Classification system used
  • Main clinical findings
  • Therapeutic    implications related  to the classification

This information was organized into summary tables, allowing for comparative analysis among the included studies.

Figure 1 presents the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flowchart, used to systematically and transparently describe the process of identification, screening, eligibility, and inclusion of the studies selected for this systematic review. This methodological model highlights the stages of article selection, ensuring reproducibility and scientific rigor in the conduct of the research on the clinical applicability of the Popkin-Golman Classification in patellar tendinosis.

Figure 1. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flowchart. SOURCE: AUTHORS.

Description and Analysis of the Flowchart Results

Initially, 273 records were identified in the consulted databases. After removing 21 duplicates, 252 studies remained for the screening stage. During the analysis of titles and abstracts, 37 records were excluded for failing to meet the established relevance criteria, resulting in 215 articles eligible for full-text reading.

In the eligibility phase, all 215 articles were evaluated in full text, of which 112 were excluded with justification, mainly for failing to meet the previously defined inclusion criteria, such as methodological inadequacy, failure to apply the classification under study, or lack of relevant clinical data.

At the end of the process, 113 studies were included in the qualitative synthesis, forming the evidence base of this systematic review. These results demonstrate a rigorous selection process, ensuring the methodological quality and scientific relevance of the analyzed studies.

Assessment of methodological quality

The methodological quality of the included studies was assessed using instruments appropriate to the study type:

• PRISMA checklist for systematic reviews
• AQUA Tool (Anatomical Quality Assessment Tool) for anatomical studies
• Critical appraisal tools for observational studies

The purpose of this assessment was to identify potential risks of bias and methodological limitations in the selected studies.

Data synthesis and analysis

The extracted data were analyzed using a qualitative narrative synthesis, considering:

• definition and evolution of the Popkin-Golman Classification
• clinical applicability
• correlation with diagnostic methods
• therapeutic implications
• limitations and gaps in the literature

Due to the methodological heterogeneity of the studies identified, no statistical meta-analysis was performed.

Ethical considerations

As this is a systematic and integrative review based exclusively on secondary data in the public domain, this study did not involve direct experimentation with human subjects or the collection of individual information. Therefore, it does not require review or approval by a Research Ethics Committee.

All included studies were properly cited and referenced, ensuring respect for copyright and the integrity of the scientific information used. The analyses and interpretations were conducted in an impartial, transparent, and responsible manner, ensuring the reliability and ethical conduct of the research.

Results

Based on the objective of this systematic review, Table 1 organizes the main findings from the literature regarding the Popkin-Golman classification applied to patellar tendinosis, with an emphasis on its conceptual basis, clinical applicability, and therapeutic implications. The synthesis was structured around thematic axes that encompass the contemporary understanding of patellar tendinopathy, the role of the classification in severity stratification, the correlation between clinical and imaging findings, and the practical implications for conservative, interventional, and surgical treatment.

In line with the model of systematic reviews focused on clinical practice, the table relates each finding to the most representative references, allowing one to visualize how the classification proposed by Popkin and Goldman fits into a broader field of evidence regarding pathophysiology, functional assessment, imaging, and therapeutic management. This type of organization facilitates the critical interpretation of studies and contributes to the rational use of the classification as a decision-making tool for patients with patellar tendinopathy.

Table 1. Key findings from the literature regarding the Popkin-Goldman classification applied to patellar tendinosis

Source: author’s own work, based on Popkin and Goldman (2016), Goldman et al. (2020), and the other references included in this systematic review.

The results summarized in Table 1 demonstrate that the Popkin-Golman classification fits into a contemporary framework in which patellar tendinosis is understood as a heterogeneous condition, determined by the interaction between mechanical overload, structural changes in the tendon, low-grade inflammatory mechanisms, and functional factors. In this context, the classification stands out for offering a proposal for the clinical organization of lesions, especially by differentiating between tendinopathy and partial ruptures of the patellar tendon, contributing to the stratification of severity and to communication among different professionals involved in care.

Analysis of the references indicates that the clinical utility of the classification is not limited to descriptive diagnosis. Its main strength lies in supporting therapeutic decision-making and management. In less advanced stages, the literature supports prioritizing conservative treatment, with an emphasis on progressive exercise programs, load control, and functional rehabilitation. In contrast, in more extensive, refractory cases, or those with greater structural compromise, the classification can aid in identifying patients who require adjuvant therapies, interventional procedures, or even surgical treatment.

Another relevant aspect is that the reviewed studies reinforce the need to integrate the classification with clinical and functional findings, avoiding decisions based solely on imaging. Pain, disability, duration of the condition, athletic demands, and response to conservative measures are fundamental variables for correctly interpreting the severity of the injury. Thus, the Popkin- Golman classification proves most useful when applied as a tool for integrated clinical reasoning, rather than as an isolated structural marker.

Overall, the findings suggest that the classification holds promise for clinical practice and for the development of therapeutic protocols in patellar tendinopathy. Although the literature points to the need for further external validation studies and prognostic correlation, the proposal has the potential to improve severity stratification, individualize treatment, and provide greater consistency in therapeutic decision-making for patients with distinct injury profiles.

Based on the specific objectives (TABLE 2) outlined in this systematic review, an in-depth analysis of the scientific literature was conducted to comprehensively understand the conceptual foundations, clinical applicability, and therapeutic implications of the Popkin-Golman Classification in patellar tendinosis. Organizing the findings into thematic categories allows for a structured and critical approach, highlighting the role of this classification in the contemporary context of sports medicine, particularly in stratifying injury severity and in the clinical and imaging correlation guiding therapeutic management. The table aims to identify gaps in scientific knowledge, contributing to the direction of future research.

Table 2. Analytical Summary of the Popkin-Golman Classification in Patellar Tendinosis

Source: Prepared by the author (2026), based on selected scientific literature.

The findings summarized in TABLE 2 demonstratethat the Popkin-Golman Classification represents a            significant advancement in the management of patellar tendinosis by integrating clinical, structural, and functional dimensions into a unified model. This feature enhances the robustness of lesion severity stratification, enabling a more precise and individualized approach to clinical management.

It is observed that its main contribution lies in the ability to correlate clinical and imaging findings, overcoming the limitations of traditional models that consider only symptoms or isolated structural changes. This integration facilitates evidence-based therapeutic decision-making, especially in determining the choice between conservative treatment and more invasive interventions. The literature reinforces that the use of the classification significantly contributes to the organization of clinical reasoning, optimization of prognosis, and better rehabilitation planning, particularly in athletes. However, despite its clinical potential, important gaps persist, especially regarding the need for prospective validation, methodological standardization, and expansion of multicenter studies.

Thus, the Popkin-Golman Classification establishes itself as a promising tool, though still in the process of scientific maturation, with the potential to become a reference in clinical practice and research on patellar tendinopathy.

Discussion

The findings of this systematic review reinforce that patellar tendinosis should be understood as a complex, multifactorial, and dynamic condition, the interpretation of which can no longer be restricted to solely mechanical or purely degenerative models. The ESSKA consensus statements presented by Abat et al. (2017, 2018) and the reviews by Scott, Backman, and Speed (2015), as well as those by Millar et al. (2017, 2021), demonstrate that tendinopathy results from the interaction between biomechanical overload, changes in the extracellular matrix, a low-intensity inflammatory response, failures in tissue repair, and insufficient structural adaptation. In this context, the Popkin-Golman Classification gains relevance precisely because it proposes a more integrated clinical interpretation of the injury, bringing structural assessment closer to therapeutic reasoning.

From a conceptual standpoint, the proposal by Popkin and Goldman (2016) and its subsequent expansion by Golman et al. (2020) represent an important step toward refining the classification of patellar tendinopathy. Unlike broader models, such as the continuum proposed by Cook, Rio, Purdam, and Docking (2016), the Popkin-Golman classification was designed to specifically address patellar tendinopathy and partial ruptures of the patellar tendon, seeking to relate the structural severity of the injury to more objective therapeutic approaches.

This characteristic was one of the most evident points in Tables 1 and 2, in which the classification stood out not only as a descriptive instrument but as a tool for clinical stratification. In other words, its utility seems to lie less in “labeling” the disease and more in organizing decision-making. This observation is particularly relevant because contemporary literature has questioned the isolated utility of classifications based solely on pain or solely on imaging. Docking, Ooi, and Connell (2015) had already demonstrated that imaging findings, while important, do not alone explain the patient’s clinical experience, and Cook et al. (2016) emphasized that tendon pathology does not necessarily follow a simple linear progression. Complementarily, Zhang et al. (2017) showed that structural changes can be detected by advanced methods, such as son elastography, but this does not imply a direct and proportional correspondence with symptom intensity.

Thus, the main contribution of the Popkin-Golman Classification appears to be precisely the attempt to overcome this dichotomy between structure and symptom, integrating clinical, functional, and imaging elements into a single interpretive model.

The clinical applicability of the classification has also proven consistent with the contemporary need for therapeutic personalization. The synthesized data indicate that stratification of lesion severity can aid in determining conservative management, progressive rehabilitation, or surgical indication, which is in line with the review by Figueroa, Figueroa, and Calvo (2016) and with the practical approach proposed by Theodorou, Komnos, and Hantes (2023).

In early or intermediate stages, treatment based on progressive loading remains the central strategy. In this regard, Breda et al. (2021) demonstrated the effectiveness of exercise therapy with progressive tendon loading, while Lim and Wong (2018), Niering and Muehlbauer (2021), Núñez-Martínez and Hernández-Guillén (2021), Pavlova et al. (2023), and de Oliveira Lemos et al. (2022) emphasized that protocols involving isometric, eccentric, and heavy slow resistance exercises promote improvements in pain and function. Rio et al. (2015, 2016) add that exercise acts not only on the tissue but also on pain modulation mechanisms and neuromuscular adaptation, broadening the understanding of treatment beyond structural repair.

Tables 1 and 2 also showed that the Popkin-Golman Classification can be particularly useful in the transition between conservative treatment and complementary or invasive therapies. The reviews by Challoumas et al. (2021, 2023) indicate that exercise remains a pillar of treatment, but adjunctive approaches may be considered in selected cases, especially when there is clinical refractoriness. In this field, percutaneous electrolysis has gained prominence. Abat et al. (2016) demonstrated the efficacy of the ultrasound- guided technique compared to conventional electrophysiotherapy, while Asensio-Olea et al. (2023) reported promising results in a meta-analysis.

The proposed biological mechanisms for this therapeutic response were reinforced by Peñin-Franch et al. (2022), who demonstrated activation of the NLRP3 inflammasome and stimulation of type I collagen production, in addition to the experimental studies by Valera-Garrido et al. (2013) and Abat et al. (2015). Nevertheless, the methodological heterogeneity of these studies calls for caution, which limits absolute generalizations.

Other adjunctive modalities, such as platelet-rich plasma, hyaluronic acid, and shockwave therapy, also emerge as complementary options, although with still variable evidence. Filardo et al. (2018) and Zhou and Wang (2016) highlighted the potential biological benefit of PRP, but without definitive consensus on protocols, indications, and magnitude of effect.

Regarding hyaluronic acid, Kaux, Samson, and Crielaard (2015), Fogli, Giordan, and Mazzoni (2017), Frizziero et al. (2019), and Gervasi et al. (2021) suggest symptomatic and functional improvement in tendinopathies, including plausibility for the patellar tendon.

With regard to shock waves, Korakakis et al. (2018), Liao et al. (2018), Waugh et al. (2015), and Sukubo et al. (2015) have demonstrated that this modality can influence pain, remodeling, and cellular response, but the results depend on the clinical context, the associated burden, and the stage of the injury. Thus, the contribution of classification, in this regard, would be to better identify which patient profiles are likely to benefit from these interventions.