[Arthrolysis for chronic flexion deficits of the knee. An overview of indications and techniques of vastus intermedius muscle resection, transposition of the tibial tuberosity and z-plasty of the patellar tendon].

AIM AND
METHOD: Limitations to the range of motion of the knee reduce knee function and life quality. Flexion deficits inhibit using stairs and shoe closure, and may cause social deprivation. We present a pathophysiological concept of arthrolysis of the knee for flexion deficit. Our concept divides into intra- and extra-articular factors involving knee stiffness. Extra-articular problems can be located proximally in the quadriceps mechanism and distally in the patellar tendon.
RESULTS: The main proximal factor is fibrosis of the vastus intermedius muscle (MVI) which is treated by MVI-resection; the main distal factor is shortening of the patellar tendon which is treated by z-plasty of the this tendon or transposition of the tibial tuberosity. Intra-articular factors are adhesions and fat pad fibrosis. These conditions can be treated by arthroscopic or limited open arthrolysis and eventually z-plasty of the retinacula.
CONCLUSION: A strict postoperative protocol is obligatory for pain control and physiotherapy. In 19 cases treated with this algorithm there was a mean flexion gain of 26 degrees. The AOSSM subjective outcome score was excellent in ten and good in seven cases after a mean follow-up of 8.2 months. This treatment protocol allows improvement in flexion, even in difficult revision cases.