# Intra-Articular Bone Marrow Aspirate Concentrate Injection in Patients with Knee Osteoarthritis
## 3 Results
### Secondary Outcome Measures  
The mean IKDC score improved from \(28.5\pm 4.3\) preoperatively to \(68.2\pm 6.0\) at the 5-year follow-up (\(p=0.02\)). The improvements in IKDC scores showed no significant differences in terms of age distribution (patients aged \(<60\) vs. those aged \(\geq 60\) years) and sex. However, the severity of knee OA was significantly associated with IKDC scores observed during the follow-up. Patients with high grades of knee OA (K-L Grade III or IV vs. K-L Grade I or II) showed low IKDC scores at the final follow-up visit, and this difference was statistically significant (Post hoc analysis, \(p<0.001\), Figure 3). \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Parameters**} & \multicolumn{5}{c}{**Mean VAS**} & \multirow{2}{*}{\(p\) *} \\ \cline{3-6}  & & **Preoperative** & **6 Months** & **12 Months** & **36 Months** & **60 Months** \\ \hline Overall & & 8.0 & 6.7 & 5.4 & 5.1 & 4.9 & - \\ \hline \multirow{2}{*}{Sex} & M & 7.6 & 6.4 & 4.8 & 4.3 & 4.2 & 0.43 \\  & F & 8.2 & 6.9 & 5.6 & 5.4 & 5.2 & 0.43 \\ \hline \multirow{2}{*}{Age} & \(<\)60 & 7.5 & 6.3 & 4.7 & 4.6 & 4.8 & \\  & \(\geq\)60 & 8.3 & 6.9 & 5.8 & 5.4 & 4.9 & 0.19 \\ \hline \multirow{2}{*}{K-L grade} & 1 & 6.0 & 3.0 & 2.0 & 2.0 & 2.0 & \\  & 2 & 6.9 & 5.8 & 4.2 & 4.0 & 3.9 & \\ \multirow{2}{*}{K-L grade} & 3 & 8.5 & 7.0 & 6.0 & 5.8 & 6.0 & \\  & 4 & 9.1 & 7.3 & 5.8 & 6.2 & 6.9 & \\ \hline \end{tabular} Note: * \(p\)-values indicate the time point between the preoperative and 60-month follow-up period. Values are presented as mean values. VAS, visual analogue scale; K-L grade, Kellgren–Lawrence grade.  
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Table 2: Pain intensity. Figure 2: Visual analogue scale (VAS) score according to the K-L grade. The mean SF-36 score also improved from \(26.8\pm 4.3\) preoperatively to \(48.2\pm 6.0\) at the 5-year follow-up (\(p<0.001\)). However, this improvement did not significantly differ in terms of age and sex. The severity of OA was significantly associated with the outcomes of the SF-36; the improvement in patients with knee OA of K-L Grade I, II, and III was significantly greater than that in patients with K-L Grade IV (ANOVA, \(p=0.02\), Figure 4). The KOOS and LKQ scores showed similar trends as the IKDC scores; the mean preoperative KOOS and LKQ scores improved significantly at the final follow-up visit (\(p<0.001\)). Similarly, high grades of knee OA were associated with poor scores at the final follow-up visit (Post hoc analysis, \(p=0.001\), and \(0.002\), respectively, Figures 5 and 6). Figure 4: 36-Item Short Form Health Survey (SF-36) score according to the K-L grade. Figure 3: International Knee Documentation Committee (IKDC) score according to the K-L grade. Secondary operations were performed in 12 patients (23 knees). Among them, 10 (19 knees) underwent TKA owing to arthritis progression and two patients (four knees) underwent a high tibial osteotomy (HTO) for progressed pain and varus alignment. The mean period for secondary operations after the BMAC injection was 28.7 months (8.5-68.5 months). The rate of secondary operations in patients with K-L Grade III or IV was significantly higher than that in patients with K-L Grade I or II (\(p\) = 0.02, Table 3). Figure 5: Knee injury and Osteoarthritis Outcome Score (KOOS) according to the K-L grade. Figure 6: Lysholm Knee Questionnaire/Tegner Activity (LKQ) according to the K-L grade. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**OA Severity (by K-L Grade)** & **Secondary Operation \({}^{*}\)** & **No Treatment** & \(p\) \\ \hline K-L Grade 1 (n = 1) & 0 (0\%) & 1 & \\ K-L Grade 2 (n = 33) & 6 (18\%) & 27 & \\ K-L Grade 3 (n = 20) & 8 (40\%) & 12 & 0.02 \\ K-L Grade 4 (n = 16) & 9 (56\%) & 7 & \\ Total (70 knees) & 23 knees & 47 knees & \\ \hline \hline \end{tabular} Note: Values are presented as the mean \(\pm\) standard deviation. K-L grade, Kellgren–Lawrence grade. \({}^{*}\) Patients underwent secondary operation during the follow-up (total knee arthroplasty in 19 knees and high- tibial osteotomy in four knees).  
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