Rethinking Patellar Tendinopathy and Partial Patellar Tendon Tears: A Novel Classification System

Abstract

Background: Patellar tendinopathy is an overuse injury of the patellar tendon frequently affecting athletes involved in jumping sports. The tendinopathy may progress to partial patellar tendon tears (PPTTs). Current classifications of patellar tendinopathy are based on symptoms and do not provide satisfactory evidence-based treatment guidelines. Purpose: To define the relationship between PPTT characteristics and treatment guidelines, as well as to develop a magnetic resonance imaging (MRI)–based classification system for partial patellar tendon injuries. Study Design: Cohort study (prognosis); Level of evidence, 2. Methods: MRI characteristics and clinical treatment outcomes were retrospectively reviewed for 85 patients with patellar tendinopathy, as well as 86 physically active control participants who underwent MRI of the knee for other conditions. A total of 56 patients had a PPTT and underwent further evaluation for tear size and location. The relationship between tear characteristics and clinical outcome was defined with use of statistical comparisons and univariate and logistic regression models. Results: Of the 85 patients, 56 had partial-thickness patellar tendon tears. Of these tears, 91% involved the posterior and posteromedial regions of the proximal tendon. On axial MRI views, patients with a partial tear had a mean tendon thickness of 10 mm, as compared with 6.2 mm for those without ( P < .001). Eleven patients underwent surgery for their partial-thickness tear. All of these patients had a tear >50% of tendon thickness (median thickness of tear, 10.3 mm) on axial views. Logistic regression showed that tendon thickness >8.8 mm correlated with the presence of a partial tear, while tendon thickness >11.45 mm and tear thickness >55.7% predicted surgical management. Conclusion: Partial-thickness tears are located posterior or posteromedially in the proximal patellar tendon. The most sensitive predictor for detecting the presence of a partial tear was patellar tendon thickness, in which thickness >8.8 mm was strongly correlated with a tear of the tendon. Tracking thickness changes on axial MRI may predict the effectiveness of nonoperative therapy: athletes with patellar tendon thickness >11.5 mm and/or >50% tear thickness on axial MRI were less likely to improve with nonoperative treatment. A novel proposed classification system for partial tears, the Popkin-Golman classification, can be used to guide treatment decisions for these patients.

Expanded adipose derived mesenchymal stromal cells are effective in treating chronic insertional patellar tendinopathy: clinical and MRI evaluations of a pilot study

“…The most sensitive predictor for the presence of a partial tendon tear in their study was the thickness of the tendon, in which thickness > 8.8 mm was strongly correlated with the presence of a tear. In the present study patients' mean thickness was 12.8 ± 1.1 mm, and in agreement to the latter study we found in all the patients a tendon tear [15]. On MRI images we also found that there was an apparent delay between the observed clinical improvement and the structural repair as shown in the 6 months post-injection.…”

“…The evaluation included the extent of tendinosis and tendon tear. The radiological interpretation was performed by two experienced sports trauma radiologists [15]. Images were reviewed on our institutional picture archiving and communication system (PACS).…”

An Objective Measure of Patellar Tendon Thickness Based on Ultrasonography and MRI in University Athletes

“…Johnson et al reported the MRI findings of patellar tendon thickness in young athletes as being 5.5 mm in asymptomatic individuals and 8.5 mm in patients with patellar tendinosis [ 15 ]. A recent study by Golman et al, which included athletes with or without a partial patellar tendon tear (PPTT) on MRI, showed an average patellar tendon thickness of 5.6 mm in asymptomatic individuals and 10.0 mm in patellar tendinopathy patients with PPTT [ 17 ]. This study also showed similar tendencies for both US and MRI; thus, it is almost certain that tendon thickness is significantly increased in patellar tendinopathy.…”

“…However, these imaging assessments currently lack evidence-based quantitative criteria or classification [ 17 ]. In particular, “thickening of the patellar tendon” is one of the indicators, but there are few articles that have quantitatively defined the thickness at which a tendon should be considered pathological.…”

Single-cell transcriptomic profiling reveals distinct mechanical responses between normal and diseased tendon progenitor cells

“…Two of the diseased subjects (D1 and D3) had (Popkin-Golman [PG]) grade 3 tendinopathy and one subject (D2) had grade 4 (Table S1). 10 Cells extracted from patients were cultured to passage 2 and subjected to flow cytometry to measure expression of common TPC markers. TPC markers of both healthy and diseased cohorts showed expression of the expected antigen profile CD31 À CD34 À CD45 À CD73 + CD90 + CD105 + (Figure S1B; Table S2), as reported previously.…”