AGT should be performed with caution in cases of 90° bending contracture. All surgical techniques used during TKA to treat preoperative flexion contracture were performed in this case, including adequate bone resection, ligament releases, removal of posterior osteophytes, and postorioral capsule releases . It is customary to perform an additional resection of the distal femur in the treatment of severe flexion contracture. One study showed that for each 10° bending contracture, an additional 2 mm of bone resection would be required . Therefore, a patient with an 80° bending contracture would need an 8 mm distal bone resection. This is somehow consistent with the current case where an additional 6 mm of bone has been resected for a 90° bending contracture. Some authors have reported that a flap implant may be required for preoperative bending contractures greater than 30° . Our patient did not need an articulated implant that would result in a greater amount of bone ablation than a posterior stabilized implant. Second, serial watering was used after surgery to treat the remaining bending contracture for four weeks. Serial watering has been shown to result in significant improvements in joint contracture in patients with hemophilia arthropathy . In this case, the objective of series casting according to TKA was to achieve a gradual and controlled extension as soon as possible, and then maintain the complete extension for one to two weeks before the casting was removed.
These changes are thought to be the result of significant improvements in the tightening of the posterior capsule, femoral biceps, gatrocnemian muscles and tendons, and collateral ligament . Although the application of series casting took some time, the costs were comparatively low. Thermal injuries should also be avoided when using series casting. In addition, casting should not be performed continuously for more than five weeks to avoid the complication of knee stiffness. In the past, various orthotics have been used, including stretch splints, to keep the joint extendable after TKA [13, 14]. However, these splints can cost more than $2,000 and require longer treatment (p.B four to 55 weeks) . In this case, our patient reached full extension in five weeks. In most cases, the bending contracture is corrected with these simple maneuvers. The type of knee prosthesis, i.e. cross-preservation or cross-sacrifice, depends on the surgeon`s choice for a light bending contracture. Laskin  described a test for the intraoperative evaluation of the correction of bending deformities.
The operated limb is lifted from the table and the foot is dorsiflexed at the ankle, then axial pressure is applied along the longitudinal axis of the limb. Sudden bending on the knee indicates a residual bending deformity. If there is no curvature on the knee due to axial pressure, this indicates sufficient correction in the knee joint. In patients with inflammatory arthritis, there is little or no osteophyte formation associated with fixed bending deformity, so preoperative manipulation is sometimes useful in some cases. In the case of bilateral hip and knee deformity, preoperative manipulation after hip replacement is performed using a series molding on the knee with maximum stretching . The plaster should be sufficiently padded to avoid pressure sores on the front appearance of the knee. Epidural anesthesia can be very useful in these cases, since serial watering becomes relatively painless and fertile. The complexity of the surgical intervention increases with the increase in the flexion deformity of the knee. Less complex deformities correct themselves with the usual bone resections and removal of osteophytes. Particular attention should be paid to the preparation of the posterior capsule. Bone resection, especially the distal femur, should be reserved in cases where the release of soft tissues does not reach sufficient flexion-extension-gap agreement.
After the operation, patients should be closely monitored to prevent recurrence of the deformity. Patients need monitoring of neurovascular status to miss an unwanted complication. Osteochondrodysplasia is a variable group of genetic bone diseases or genetic skeletal dysplasia that occur with generalized bone deformities that affect all extremities and the spine. Genu valgum or knock knees is one of the known skeletal manifestations of osteochondrodysplasia. A complete radiographic examination of the bones is mandatory to obtain a definitive diagnosis.  Arthritic and non-arthritic joints can develop “arthrofibrosis.” In this state, the knee can not stretch completely. This is called inflection contracture. People with this disease walk with the knee bent to varying degrees. The photo below shows a patient with a large flexion contracture in the right leg.
Although they can stretch their left leg so that it rests flat on the table, this is a straight line as the right leg can become. The angle that the knee makes can be measured and is called the degree of bending contracture. The higher the number, the more bent the knee. Al-Oraibi S, Tariah HA, Alanazi A. Serial casting versus stretching technique for the treatment of squat contracture in children with spina bifida: a comparative study. J Pediatr Rehabil Med. 2013;6:147-53. Nutritional rickets is an important cause of genu valgum or knees in childhood in some parts of the world.
Nutritional rickets comes from unhealthy lifestyle habits like insufficient sun exposure, which is the main source of vitamin D. Insufficient dietary intake of calcium is another contributing factor.   Genu valgum may stem from rickets caused by genetic abnormalities called vitamin D-resistant rickets or X-linked hypophosphatemia. Campbell TM, Trudel G, Laneuville O. Knee flexion contractures in patients with osteoarthritis: clinical features and histological characterization of the posterior capsule. PMR. 2015;7:466–73. Patients are encouraged to perform quadriceps exercises at regular intervals. In case of slight residual bending deformity, patients are recommended to wear night splints. Stretching exercises play an important role in the rehabilitation of these cases. It is recommended to avoid the pillow below the knee and sit for a long time on sun loungers, as there is a tendency to bend.
Patients should be closely monitored in the postoperative period for recurrence of the deformity. Sometimes patients need manipulation under anesthesia to achieve a range of motion similar to that of the immediate postoperative period. Excessive force should be avoided when handling, as this can lead to rupture of the distal femur. Walking with a bent knee is an abnormal posture. It causes increased pressure and “wear” on the knee when walking, especially on the patella. The end result is pain and disability. The worse the bending contracture, the faster the symptoms appear. But even slight bending contractures can lead to disabilities if left untreated. A study by Riddle found that over three years, for every degree of bending contracture present, the risk of having knee replacement increased by 6%. 1. Recurrence of bending contracture and loss of movement In the present study, a new protocol for the treatment of severe knee flexion contractures greater than 80° has been developed. .