Baker Cyst aspiration and intra-articular knee joint injection
Lu Mao (lmao@biostat.wisc.edu)
2023-02-20
Descriptive analysis
Descriptive statistics for key variables are summarized below by “Baker Cyst aspiration and corticosteroid injection” vs “Baker Cyst aspiration and intra-articular knee joint injection”.
| No knee joint (N=50) | Knee joint (N=24) | p-value | |
|---|---|---|---|
| Age (years) | 64 (52.2, 68) | 61.5 (50, 73.2) | 0.724 |
| Sex - F | 38 (76%) | 12 (50%) | 0.035 |
| Sex - M | 12 (24%) | 12 (50%) | |
| Laterality - L | 28 (56%) | 8 (33.3%) | 0.085 |
| Laterality - R | 22 (44%) | 16 (66.7%) | |
| Size (cm^3) | 18.9 (8.5, 44) | 20.2 (11.2, 35) | 0.799 |
| Aspiration volume | 6 (2, 16.5) | 6.5 (2, 13.2) | 0.94 |
| Baker cyst - Simple | 34 (68%) | 14 (58.3%) | 0.445 |
| Baker cyst - Complex | 16 (32%) | 10 (41.7%) | |
| Osteoarthritis - 0 | 12 (26.7%) | 5 (21.7%) | 0.776 |
| Osteoarthritis - 1 | 12 (26.7%) | 8 (34.8%) | |
| Osteoarthritis - 2 | 11 (24.4%) | 6 (26.1%) | |
| Osteoarthritis - 3 | 8 (17.8%) | 2 (8.7%) | |
| Osteoarthritis - 4 | 2 (4.4%) | 2 (8.7%) | |
| Pain score pre | 4.2 (2.5, 7) | 5 (3.9, 7.1) | 0.168 |
| Change score immed. post | -3 (-5, -2) | -3.2 (-5, -2) | 0.749 |
| Change score 14d. post | -3 (-5.9, -1.6) | -3 (-5.2, -1.9) | 0.912 |
Categorical variables are summarized by N (%) and quantitative variables by median (IQR). p-value is based on Wilcoxon rank sum test for quantitative variables and Fisher’s exact test for categorical variables.
Comparison of pain score changes
From the last three lines of Table 1 and the boxplots below, there appears to be no systematic difference in pain score changes from pre- to post-intervention (both immediately and 14 days after) between “knee joint injection” and “no knee joint injection”.
Factors impacting pain score changes
The follow graphs examine the impact of sex, age, degree of osteoarthritis, volume aspirated, and complex versus simple fluid collection on changes in pain score, both immediately and 14 days post-intervention. In particular, older age is significantly associated with greater immediate reduction in pain score (p=0.015).
Factors impacting pain score changes (for the group with knee joint injection)
Factors impacting pain score changes (for the group with no knee joint injection)
