目的：描述護理之家住民兩個月下肢被動關節角度的改變情形，並找出可能影響其改變之危險因子。方法：共徵召48位平均年齡為75.0歲，年齡範圍在41～93歲之間之28位男性和20位女性護理之家住民參與本研究。由同一位施測者收集住民基本資料、活動情形、物理檢查及物理治療介入與下肢關節被動關節角度（包括髖屈曲與伸直、膝屈曲與伸直、踝關節背曲與蹠屈），並於兩個月後再測量其下肢關節被動關節角度，以描述兩個月下肢被動關節角度的改變情形並分析可能影響其改變之危險因子。結果：在兩個月當中，護理之家住民的髖屈曲、髖伸直、膝屈曲及踝背屈等被動關節角度隨著時間達統計上顯著惡化(p<0.05)。可能影響下肢被動關節角度改變之危險因子在各關節動作有所不同。在髖屈曲，屬於健肢、兩個月前之髖屈曲角度愈大者愈易惡化；在膝屈曲，中風病人姿勢評估量表分數愈高者愈易惡化；在膝伸直，進行被動膝伸直角度測量時之力矩愈大、屬於發病時間未超過一年者愈易惡化；在踝背屈，踝蹠屈肌有張力者愈易惡化；在踝蹠屈，兩個月前之踝蹠屈角度愈大愈易惡化。結論：護理之家住民之下肢被動關節角度在兩個月期間就會發生明顯的惡化，對於關節角度較佳的健肢、活動能力較佳的個案、進行被動運動時阻力較大的關節以及發病一年內的住民應特別加强其關節運動以避免角度的惡化，造成未來照顧上的困難。

Purpose: The aims of this study were to describe the changes of passive range of motion (PROM) over 2-month period for lower extremity joints and to identify potential risk factors in nursing home residents. Methods: Forty-eight nursing home residents who were able to participate in at least two evaluation sessions within 2 months were recruited (mean age=70.5 years old; 28 males, 20 females). The following data were collected from each resident: demographic characteristics; mobility status(Postural Assessment Scale for Stroke patients); physical examination(pain status, muscle tone, strength, timed up and go test, BarthelIndex, etc.); duration of physical therapy interventions (min); passive joint ranges (degree) of bilateral hip, knee and ankle flexion and extension. The passive ranges of motion were measured again two months later. Results: The PROMs of the hip flexion, hip extension, knee extension and ankle dorsiflexion decreased significantly over two months (p<0.05). The occurrence of hip flexion range deterioration is higher if it was the sound side (odds ratio=1.057;95%CI 1.012 to 1.104) and had a higher baseline PROM (odds ratio=2.678;95%CI 1.063 to 6.744). The occurrence of hip extension range deterioration is higher if the subject had higher scores in PASS (odds ratio=1.090;95%CI 1.021 to 1.163). The occurrence of knee extension range deterioration is higher if it had higher resistance to passive joint motion (odds ratio=1.357;95%CI 1.091 to 1.689) and the subject had length of disease onset less than one year (odds ratio=0.191;95%CI 0.049 to 0.740). The occurrence of ankle dorsiflexion range deterioration is higher if it had abnormal muscle tone over ankle plantarflexor (odds ratio=3.619; 95%CI 1.025 to 12.770). The occurrence of ankle plantarflexion range deterioration is higher if it had a higher baseline PROM (odds ratio=1.083; 95%CI 1.023 to 1.147). Conclusions: Nursing home residents demonstrated significant deteriorations in lower extremity joints PROM in as short as 2 months duration. Being the sound side, having a better baseline range of motion, having better bed mobility, having increased resistance to PROM, or onset of major diseases within 1 year are main risk factors for joint range deteriorations.