Correlation among Radiographic, Arthroscopic and Pain Criteria for the Diagnosis of Knee Osteoarthritis

Abstract

Introduction: Osteoarthritis (OA) is the most common degenerative joint disorder leading to functional impairment and dependency in older adults. Early detection and intervention is of paramount importance in decreasing the morbidity. Radiography is the first investigation of choice for OA patients presenting with knee pain. But, there is a high degree of discordance between clinical and radiographic findings. Arthroscopy aids in accurate diagnosis of OA knee.

Aim: In view of the conflicting reports in the literature the present study was undertaken to report the correlation among radiographic, arthroscopic and pain findings in knee OA patients to facilitate early and precise diagnosis.

Materials and methods: Twenty eight cases (14 males and 14 females) of primary OA knee (7 each from radiographic grade 1 to 4) were screened and selected for the study. Spearman's rank correlation coefficients (Rho/r estimate) were calculated to determine the relationship between pain, radiographic and arthroscopic grades in patients with knee OA.

Results: Among 28 patients, 10.71% had grade 1, 14.28% had grade 2, 25% had grade 3 and 50% had grade 4 arthroscopic findings. Overall Spearman's correlation coefficient (r) for radiographic and arthroscopic grades was 0.8077, 0.8212 for radiographic and pain grades and 0.7634 for arthroscopic and pain grades. Correlation coefficient could not be calculated for individual grades in isolation which would otherwise represent the factual correlation. The Mean arthroscopic grade for radiographic grades 1 to 4 were 1.57, 3.42, 3.57,4.0 respectively and the Mean pain grades for radiographic grades 1 to 4 were1.57, 2.57,3.28, 3.57 respectively. Radiological findings were found to lag behind the arthroscopic findings significantly.

Conclusion: Arthroscopic findings represent the exact extent and degree of the pathology of OA knee. Kellgren-Lawrence grading read with conventional Antero-posterior standing radiographs of knee underscores the arthroscopic findings significantly in grades 1, 2 and 3. Radiological and clinical findings (Apley's pain grading) in combination should be considered in concluding the final diagnosis and treatment of OA knee. Improvised criteria for precise diagnosis have to be evolved.

Keywords: Apley’s pain score; Arthroscopy; Kellgren Lawrence; Outerbridge.

[Table/Fig-1]:

Original photos- Antero-posterior radiographs representing each grade of osteoarthritis in ascending order

[Table/Fig-2]:

Original photos-Depiction of arthroscopic findings in the ascending order of severity of articular cartilage damage

[Table/Fig-4]:

Bar diagram depicting the number of patients in each grade

[Table/Fig-5]:

Spearman’s correlation coefficient graph for radiographic and arthroscopic grades (overall)

[Table/Fig-6]:

Spearman’s correlation coefficient graph for pain and radiographic grades (overall)

[Table/Fig-7]:

Spearman’s correlation coefficient graph for arthroscopic and pain grades (overall) RG- Radiographic grade, PG-Pain grade, AG-Arthroscopic grade

[Table/Fig-10]:

(a) Arthroscopic Grade 1. (b) Arthroscopic Grade 2. (c) Arthroscopic Grade 3. (d) Arthroscopic Grade 4 Scatter plots for correlation of radiographic, pain grade and percentage of patients with different arthroscopic grades (1to 4)