Scott R D, Turoff N, Ewald F C
Clin Orthop Relat Res. 1982 Oct(170):147-51.
Stress fracture of the patella can occur with significant frequency following patellar replacement with the duopatellar knee prosthesis. In the first 372 knees with patellar resurfacing, the incidence was 0.7% in rheumatoid arthritis (2 fractures in 286 knees) and 3.5% in osteoarthritis (3 fractures in 86 knees). The incidence may be greater in osteoarthritic patients because they have more function and are generating greater force across the patellofemoral joint. There was an association with osteonecrosis of the patella in at least three cases in which a lateral retinacular release had been performed and the lateral superior genicular artery sacrificed. This vessel should be preserved during a lateral release to save its contribution to the blood supply of both the patella and the lateral skin flap. Initial treatment of the stress fractures can be nonoperative, with surgery necessary only if the patellar prosthesis has become dislodged, or if pain or inadequate active extension persists. If the fracture can not be repaired, patellectomy can yield a good result. To avoid stress fracture, a minimal amount of patellar articular surface should be resected and the peripheral cortex of both the medial and lateral facets preserved. Fewer stress fractures may occur if a smaller fixation lug is used, thereby preserving more patellar bone stock.
采用双髌骨膝关节假体进行髌骨置换后，髌骨应力性骨折可能会频繁发生。在最初的372例行髌骨表面置换的膝关节中，类风湿性关节炎患者的发生率为0.7%（286例膝关节中有2例骨折），骨关节炎患者的发生率为3.5%（86例膝关节中有3例骨折）。骨关节炎患者的发生率可能更高，因为他们的功能更多，髌股关节承受的力量更大。至少有3例与髌骨坏死有关，这些病例均进行了外侧支持带松解并牺牲了膝上外侧动脉。在进行外侧松解时应保留该血管，以保护其对髌骨和外侧皮瓣血供的贡献。应力性骨折的初始治疗可以是非手术治疗，只有在髌骨假体移位、疼痛持续或主动伸直不足时才需要手术。如果骨折无法修复，髌骨切除术可能会取得良好效果。为避免应力性骨折，应尽量减少髌骨关节面的切除，并保留内外侧小面的周边皮质。使用较小的固定凸耳可能会减少应力性骨折的发生，从而保留更多的髌骨骨量。
