Short-term outcomes of trochlear recession surgery combined with “Watermelon” autograft for treatment of canine medial patellar luxation: a case series

ABSTRACT The aim of this study was to present a novel surgical method for correction of medial patellar luxation in small-breed dogs with trochlear dysplasia and marked hypoplasia of the medial femoral condyle. The “Watermelon” approach was applied together with trochlear wedge recession or trochlear block recession and consisted in increasing the height of the medial condyle with an osteochondral autograft resembling a watermelon slice, placed into an additional slot in the medial femoral condyle to prevent the postoperative reluxation of the patella. The study cohort included 19 dogs (25 joints) from small breeds (Pinscher, Pomeranian, and Chihuahua) with second-grade medial patellar luxation. Fourteen joints were submitted to wedge recession surgery combined with “Watermelon” grafting, and 11 joints: to block recession surgery with “Watermelon” grafting. The sulcus-deepening trochleoplasty combined with “Watermelon” grafting was clinically successful and with low percentage of minor postoperative complications. The mean duration of anesthesia was significantly longer for block recession combined with “Watermelon” (P<0.001), but the recovery period was shorter (P<0.05).摘要 本研究旨在提出一种全新的手术方法，用于治疗患有滑车发育不良（trochlear dysplasia）且股骨内侧髁（medial femoral condyle）显著发育不全的小型犬的内侧髌骨脱位（medial patellar luxation）。本研究采用"西瓜"术式（"Watermelon" approach）联合滑车楔形凹陷成形术（trochlear wedge recession）或滑车块状凹陷成形术（trochlear block recession）：通过截取形状类似西瓜片的自体骨软骨移植物（osteochondral autograft），植入股骨内侧髁的额外槽道中以增高内侧髁高度，从而防止术后髌骨再脱位。本研究的研究队列（study cohort）共纳入19只小型犬（共25个关节），均患有二级内侧髌骨脱位（second-grade medial patellar luxation），涉及品种包括平舍犬、博美犬与吉娃娃。其中14个关节接受了滑车楔形凹陷成形术联合"西瓜"移植物植入术，剩余11个关节则接受滑车块状凹陷成形术联合"西瓜"移植物植入术。联合"西瓜"移植物植入的加深滑车沟成形术（sulcus-deepening trochleoplasty）临床效果良好，且术后轻微并发症发生率较低。接受滑车块状凹陷成形术联合"西瓜"术式的病例平均麻醉时长（mean duration of anesthesia）显著更长（P<0.001），但术后恢复周期（recovery period）更短（P<0.05）。