**8. Clinical results and complications**

The clinical results of TKA in SKNs are inferior in comparison with non-stiff knees with higher complication rates [21, 30]. The rate of complications ranges from 21–35% [31, 32]. The common complications are patellar tendon avulsion, partial or complete tear of MCL, bone fracture or avulsion (epicondyle (s), patella), stiffness after TKA, wound dehiscence, ligamentous imbalance between extension, and flexion gap. Gentle knee flexion and progressive subperiosteal soft tissue releases with the electrocautery can prevent intraoperative bone fracture. It is not uncommon a painful TKA in SKNs that can be a challenging situation to achieve a better functional outcome. Extension lag is associated with V-Y quadricepsplasty [32]. Aseptic loosening in the tibial component has been described in some SKNs [32, 33]. Osteoporotic bone can be considered as a risk factor for fractures around the knee.
