Flexion contractures are not uncommon before total knee arthroplasty (TKA), occurring in patients with varus and valgus gonarthrosis.

A flexion contracture of greater than 5° to 10° requires complete surgical correction, as residual contractures after TKA can lead to reduced function and walking ability.

The etiology can be multifactorial; however, it is more common with more severe knee deformities, posttraumatic and inflammatory arthritis, prior surgery (i.e., knee arthroscopy, high tibial osteotomy), and neuromuscular disorders.

The sagittal plane deformity is typically corrected first through bone resection and removal of osteophytes and releasing shortened soft tissue.

It is important to perform maneuvers that preferentially open the extension gap and do not affect the flexion gap, as this can lead to a flexion-extension gap mismatch.

Supine

A midline incision with a medial parapatellar arthrotomy is performed in almost every instance.

Rarely, a lateral arthrotomy may be considered for severe valgus gonarthrosis.

A full complement of knee radiographs is recommended, including a long-leg hip-knee-ankle radiograph (Figure 55.1), standing anteroposterior (AP) radiograph (Figure 55.2), standing posteroanterior (PA) flexion radiograph (Figure 55.3), lateral radiograph (Figure 55.4), and patellar views (Figure 55.5).

The radiographs are used to anticipate areas of the knee that will require releases to improve the flexion contracture (i.e., posterior osteophytes [Figure 55.6]/loose bodies [Figure 55.7]) or bone deformities that will have to be addressed (i.e., tibial slope, intra-articular posttraumatic deformities) (Figure 55.8).

A physical examination should document the degree of passive correction of the flexion deformity to anticipate the degree of surgical correction/releases required.