Drew J, Glyde M, Hosgood G, Newman M
College of Veterinary and Life Sciences, Murdoch University Nyarrie Drive, Murdoch, Western Australia 6150, Australia.
Small Animal Surgery, Murdoch, WA, Australia.
Aust Vet J. 2018 Nov;96(11):428-432. doi: 10.1111/avj.12761.
Patella alta is the proximal displacement of the patella within the femoral trochlea. Previous studies have identified an association between patella alta and patella luxation. Distalisation of the tibial tuberosity has been recommended to establish proximodistal alignment of the stifle extensor mechanism with the underlying femur in dogs affected by patella alta. However, a recent canine ex vivo study found stifle extensor mechanism load increased significantly following tibial tuberosity distalisation. Generation of excessive load within the stifle extensor mechanism was avoidable by performing a combined transverse femoral ostectomy and tibial tuberosity distalisation.
Two dogs presented with acute onset left hindlimb lameness and medial patella luxation. The left patellar ligament length to patella length ratio was 2.37 and 2.39 in each dog (reference range 1.33-2.06), consistent with patella alta. No other stifle abnormalities were identified. Proximodistal stifle extensor mechanism alignment was corrected with a combined transverse femoral ostectomy and tibial tuberosity distalisation. The postoperative ratio of the distance between the proximal pole of the patella and femoral condyle to patella length ratio (A : P) fell within the corrected reference range (1.52-2.44). Follow-up orthopaedic examination and postoperative radiographs at 10-12 weeks demonstrated clinical bone union of the femoral ostectomy and tibial tuberosity distalisation sites. No evidence of medial patella luxation or lameness could be detected.
A combined transverse femoral ostectomy and tibial tuberosity distalisation technique resolved medial patella luxation with patella alta in two dogs. Additionally, the normal A : P reference interval should be corrected to 1.52-2.44.
高位髌骨是指髌骨在股骨滑车内向近端移位。既往研究已证实高位髌骨与髌骨脱位之间存在关联。对于患有高位髌骨的犬，建议通过胫骨结节远移术来建立膝关节伸肌机制与股骨之间的近远侧对线关系。然而，最近一项犬离体研究发现，胫骨结节远移术后膝关节伸肌机制负荷显著增加。通过联合进行股骨横向截骨术和胫骨结节远移术可避免膝关节伸肌机制内产生过大负荷。
两只犬出现急性左后肢跛行及内侧髌骨脱位。每只犬的左髌韧带长度与髌骨长度之比分别为2.37和2.39（参考范围为1.33 - 2.06），符合高位髌骨表现。未发现其他膝关节异常。通过联合股骨横向截骨术和胫骨结节远移术纠正了膝关节伸肌机制的近远侧对线关系。术后髌骨近端极点与股骨髁之间的距离与髌骨长度之比（A : P）落在校正后的参考范围内（1.52 - 2.44）。术后10 - 12周的随访骨科检查及X线片显示股骨截骨术和胫骨结节远移术部位临床骨愈合。未检测到内侧髌骨脱位或跛行的迹象。
联合股骨横向截骨术和胫骨结节远移术技术解决了两只犬因高位髌骨导致的内侧髌骨脱位问题。此外，正常的A : P参考区间应校正为1.52 - 2.44。
