Coexistence of Low Back Pain and Lumbar Kyphosis and the Association With Increased Functional Disability in Knee Osteoarthritis: Results From a Population‐Based Cohort

Abstract

Objective To examine the association of low back pain (LBP) and lumbar kyphosis with functional disabilities and knee symptoms in patients with knee osteoarthritis (OA). Methods We analyzed 586 participants (80.1% female; mean ± SD age 68.8 ± 5.2 years) from the Nagahama Study who were age ≥60 years and had radiographically confirmed knee OA. The Knee Society Knee Scoring System (KSS) was used to assess functional disabilities and knee symptoms. LBP was defined as the presence of any persistent back pain for more than 3 months. Lumbar kyphosis was determined by skin‐surface methods using a computer‐aided electronic device called the Spinal Mouse. Multiple linear regression analysis was used for assessing the association of LBP and lumbar kyphosis with the KSS scores. Subgroup analyses based on sex were also performed. Results LBP and lumbar kyphosis were independently associated with a lower KSS function score after adjustment for covariates (mean difference −4.96 [95% confidence interval (95% CI) –7.56, –2.36] points for LBP alone, mean difference –4.47 [95% CI –8.51, –0.43] points for lumbar kyphosis alone, and mean difference –13.86 [95% CI –18.86, –8.86] points for the coexistence of LBP and lumbar kyphosis, respectively). The coexistence of LBP and lumbar kyphosis in women was associated with a lower KSS symptom score (mean difference –4.49 [95% CI –6.42, –2.55] points). Conclusion These findings suggest that both LBP and lumbar kyphosis are useful clinical signals indicating functional disability and knee symptoms in patients with knee OA.

Biomechanical and clinical relationships between lower back pain and knee osteoarthritis: a systematic review

“…A further 75 studies were excluded at the second stage of screening (full text), mainly because the studies were not assessing any causation or relationship, not both the interested conditions were explored, or because of non-peer-reviewed publications such as conference proceedings, commentaries, and research notes. Thirteen studies [ 6 – 9 , 12 , 16 – 23 ] were therefore included into the final analysis of the current review (Table 1 ) (Fig. 1 ).…”

“…Outcome measures assessed were related to the knee were pain, disability, knee range of motion (ROM), and KOA severity grades. There were seven studies assessing biomechanical associations [ 9 , 16 , 18 – 20 , 22 , 23 ] and 10 of studies assessing clinical outcomes [ 6 – 8 , 12 , 16 – 18 , 21 – 23 ]. There were six studies evaluating the outcomes related to knee pain and disability [ 7 , 8 , 17 , 18 , 20 , 23 ] (Table 2 ), six studies evaluating the outcomes related to back pain and disability [ 6 , 8 , 17 , 18 , 21 , 22 ], one study measuring the knee flexion angle [ 20 ], the spinal ROM [ 18 ], and one study evaluating the knee OA severity [ 22 ] (Table 2 ).…”

“…Thus, sagittal lumbo-pelvic malalignment, especially pelvic retroversion, could lead to the progression of KOA. Furthermore, lumbar kyphosis in women was found to be associated with a lower Knee Society Knee Scoring System (KSS) symptom score [ 23 ].…”

“…Both LBP and lumbar kyphosis are useful clinical signals and indicate functional disability and knee symptoms in patients with knee OA [ 23 ]. LBP and lumbar kyphosis were independently associated with a lower KSS function score [ 23 ]. The coexistence of LBP and lumbar kyphosis in women was associated with a lower KSS symptom score [ 23 ].…”

“…LBP and lumbar kyphosis were independently associated with a lower KSS function score [ 23 ]. The coexistence of LBP and lumbar kyphosis in women was associated with a lower KSS symptom score [ 23 ].…”