Background <p>Thrombosis is a common postoperative complication after unicompartmental knee arthroplasty (UKA), and the ability to squat is an important functional outcome reflecting recovery of knee function. This study aimed to investigate the factors influencing postoperative thrombosis as well as the ability to squat within 1 year after UKA.</p> Methods <p>Data from UKA patients were retrospectively analyzed and grouped based on the occurrence of thrombosis (including deep vein thrombosis and superficial vein thrombosis) and the ability to squat within 1 year. Factors affecting thrombosis and squatting were compared and analyzed using multifactorial logistic regression.</p> Results <p>Univariate analysis revealed that age (<i>P</i> = 0.014), pre-operative haemoglobin (<i>P</i> = 0.044), and gender (<i>P</i> = 0.047) were associated with thrombosis, while multifactorial analysis found age (<i>P</i> = 0.024) as the key factor. Regarding squatting ability, univariate analysis identified age (<i>P</i> = 0.018), body weight (<i>P</i> = 0.001), BMI (<i>P</i> = 0.001), waist circumference (<i>P</i> &lt; 0.001), pre-operative VAS score (<i>P</i> = 0.002), and family living conditions (<i>P</i> = 0.019) as influencing factors, with multifactorial analysis identifying waist circumference (<i>P</i> = 0.002) as a significant factor.</p> Conclusions <p>Older age increases the likelihood of thrombosis after UKA. Additionally, a larger waist circumference decreases the likelihood of squatting within 1 year after surgery.</p>