2015 ISAKOS Biennial Congress ePoster #208

Resolution Rate and Improving Rate of Subjective Knee Condition in Japanese Community Dwelling Populations From 5-Year Cohort Study

Eiji Sasaki, MD, PhD, Hirosaki, Aomori JAPAN
Eiichi Tsuda, Prof., Hirosaki, Aomori JAPAN
Yuji Yamamoto, MD, Hirosaki, Aomori JAPAN
Shugo Maeda, MD, Hachinohe, Aomori JAPAN
Takuya Naraoka, MD, Fujinomiya, Shizuoka JAPAN
Yuka Kimura, MD, Hirosaki, Aomori JAPAN
Daisuke Chiba, MD, PhD, Hirosaki, Aomori JAPAN
Yasuyuki Ishibashi, MD, Hirosaki, Aomori JAPAN

Hirosaki University Graduate School of Medicine, Hirosaki, JAPAN

FDA Status Not Applicable

Summary: Five-year longitudinal study, examined resolution rate and improving rate of knee condition, revealed that knee function only slightly got less severe naturally, while approximately a quarter to one half of knee pain and QOL improved.



Objectives: Symptoms with knee osteoarthritis vary widely, and change with time or activities. The correlation of symptoms with radiographic severity of knee OA is controversial. This confuses the criteria of diagnosis of knee osteoarthritis and indication for surgery. Furthermore, it is unclear how long symptoms last and change with time. The purpose of this study was to examine the change of knee symptoms by a valid subjective scale in individuals followed for 5 years.


We prospectively enrolled 448 community dowelling individuals (158 males and 284 females) and followed them for 5 years. Their mean age was 57.2 ± 10.9 years old. Anterior-posterior weight bearing knee radiographs were obtained at baseline and endpoint. Appearances of OA were graded according to Kellgren–Lawrence (KL) grade, and they were classified into three groups: Normal (KL grade 0 or 1), Moderate (grade 2) and Severe (grade 3 or 4). Joint space width was measured using the Knee Osteoarthritis Computer-Aided Diagnosis (KOACAD) system. The degree of knee condition was quantified by Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline and endpoint. Resolution rate and improving rate of knee condition was calculated and their related factors were estimated by linear regression analysis taking into account age, gender, body mass index, and lifestyle habits.


At the baseline, the normal group included 321 participants, while 91 were in the moderate, and 30 in the severe group. Osteoarthritis developed from normal in 129 of 321 knees, and progressed from moderate in 47 of 91 knees. Six participants received total knee arthroplasty. Joint space narrowing over 5 years was 0.23 ± 0.55 mm, 0.15 ± 0.48 mm in the normal, 0.30 ± 0.49mm in the moderate, and 0.97 ± 0.75mm in the severe group (ANOVA: p<0.001). Resolusion rate of KOOS-Pain was 12.2%, KOOS-Symptom was 13.3%, KOOS-ADL was 9.0%, KOOS-Sports/Recreation was 14.0%, and KOOS-QOL was 11.5%. Improving rate of KOOS-Pain with severity was 24.5, 42.2, and 40.0%, KOOS-Symptom was 29.2, 35.6, and 50.0%, KOOS-ADL was 14.3, 25.6, and 26.7%, KOOS-Sports/Recreation was 25.2, 41.1, 30.0%, and KOOS-QOL was 27.6, 40.0, 43.3%, respectively. Regression analysis showed that there was correlation between joint space narrowing and decreasing KOOS-ADL score (p=0.041) in normal knees. And, lower frequency of fitness was correlated to decreasing KOOS-total score in the moderate group (p=0.030). There was no related factor in the severe group.


The present longitudinal study revealed resolution rate and improving rate of knee condition. The knee function scored by KOOS-ADL and KOOS-Sports/Recreation only slightly got less severe naturally, while approximately a quarter to one half of knee pain and QOL improved. Few individuals with radiographic knee osteoarthritis continued to suffer from knee pain, disability, or decreasing QOL, even those with severe knee osteoarthritis. These results supplied important information to understand clinical presentation of knee osteoarthritis.