Science of Health Orthopaedic Department, Molise University, Campobasso, Italy.
Knee Surg Sports Traumatol Arthrosc. 2011 Apr;19(4):663-70. doi: 10.1007/s00167-010-1329-4. Epub 2010 Dec 11.
Predisposing factors to objective patellar instability include trochlear dysplasia, patella alta, patellar tilt and elevated tibial tuberosity-femoral groove distance. The shape of the patella is classically not considered a predisposing factor. Anomalies of dynamic and static factors, including excessive patellar height, tibial tubercle lateralisation or trochlear dysplasia, may influence the development of the patella.
One hundred and five patients (140 knees) with objective patellar instability were retrospectively reviewed to identify a possible association between the above-mentioned predisposing factors and patellar shape. All patients were evaluated with static and dynamic CT scans, and plain lateral and antero-posterior radiographs, and skyline patellar views.
Evidence of a significant association emerged between patellar shape and patellar tilt in static (r(s) = 0.20, P = 0.019) or dynamic conditions (r(s) = 0.18, P = 0.031) and a significant association between Wiberg patellar shape type C and trochlear dysplasia grade 3 (χ(2) = 4.5, P = 0.035). Also, we found a significant association between trochlear dysplasia stage 3 and tibial tuberosity-trochlear groove (TT-TG) and patellar tilt relaxed (P < 0.01 and P < 0.05, respectively). There is an association between patellar shape and patellar tilt.
Increased lateral stresses may produce a Wiberg type C patella, with a hypoplastic medial facet and a more developed lateral facet. Unbalance between dynamic medial and lateral stabilisers may act as an additional factor. A rehabilitation program aiming to reduce this unbalance may decrease the incidence of type C patella in young patients.
客观髌骨不稳定的诱发因素包括滑车发育不良、高位髌骨、髌骨倾斜和胫骨结节-股骨滑车沟距离升高。髌骨的形状通常不被认为是一个诱发因素。动态和静态因素的异常，包括髌骨高度过高、胫骨结节外侧化或滑车发育不良，可能会影响髌骨的发育。
回顾性分析 105 例（140 膝）客观髌骨不稳定患者，以确定上述诱发因素与髌骨形状之间是否存在关联。所有患者均接受静态和动态 CT 扫描、常规侧位和前后位 X 线片以及髌骨关节切线位片检查。
在静态（r(s) = 0.20，P = 0.019）或动态条件下（r(s) = 0.18，P = 0.031），髌骨形状与髌骨倾斜之间存在显著相关性，Wiberg 髌骨形状 C 型与滑车发育不良 3 级之间存在显著相关性（χ(2) = 4.5，P = 0.035）。此外，我们发现 3 级滑车发育不良与胫骨结节-滑车沟（TT-TG）和髌骨松弛倾斜之间存在显著相关性（P < 0.01 和 P < 0.05）。髌骨形状与髌骨倾斜之间存在相关性。
外侧压力增加可能导致 Wiberg 型 C 髌骨，即内侧关节面发育不良，外侧关节面更发达。内侧和外侧动态稳定器之间的不平衡可能是一个额外的因素。旨在减少这种不平衡的康复计划可能会降低年轻患者 C 型髌骨的发生率。
