TKA is one of the most successful surgeries performed with excellent 15-20-year survivorships routinely reported in large series by multiple surgeons. It is widely used in the treatment of severe knee osteoarthritis, Inflammatory arthritis, rheumatoid arthritis, gout and other general arthritic conditions. When the medical treatments antalgic and anti-inflammatory medications, heel wedges, off-loading knee braces, weight reduction, activity modification, the use of ambulatory aids , intra-articular corticosteroid or viscosupplementation injections, physiotherapy have failed, time is coming to implant a prosthesis to relieve pain and to restore knee function.
The devices are composed of :
The patellar surface is not always damaged and in that case the surgeon doesn't resurface it.
One successful design concept that has evolved over the last 3 decades is the use of mobile-bearing TKA : it allows unimpeded freedom of the polyethylene inserted between the femur and tibia to rotate around a central post on a highly polished, cobalt-chrome tibial surface.
Kinematically, the native knee joint is much more complicated than a simple "hinge" joint. TKA attempts to recreate the complicated sagittal and rotational plane kinematic motions that occur during range of motion in the normal knee.
The mobile-bearing TKA allows increasing implant conformity and substantially increases contact area, reduces contact stresses, and lowers polyethylene wear. This is supported by in vitro testing and the excellent long-term clinical results with minimal loosening reported in numerous studies.
It improves control of anteroposterior translation with reduced paradoxical anterior femoral translation and self- aligning behavior to maintain large, centrally located surface contact areas at the femorotibial articulation during both flexion extension and axial rotation of the knee which is much more difficult to achieve in fixed-bearing TKA designs.
The rotational freedom provided by rotating-platform TKA designs assists in maintaining self-alignment of both the patellofemoral and femorotibial articulations throughout knee flexion, lessens polyethylene surface stresses, and reduces polyethylene wear by decoupling multidirectional motions to more unidirectional motion patterns at 2 differing interfaces, thus reducing cross-shear stresses and wear.
In order to detect vital risk for anesthesiology, and to assess a potential risk of post-operative complication in a short or long term follow-up, a medical questionnaire checking list is needed to be accepted by the surgeon and his team.
Risk factors influencing complications are :
Factors increasing risk of infection
Factors increasing risks for medical complications
One of the advanced technique is minimally invasive TKR : It allows less blood loss, less pain, a shorter length of hospitalisation stay and an earlier return to function.
This technique of MIS knee surgery involves many different steps :
Approach is performed by incising the vastus medialis or along the border of the quadriceps tendon (green line 1, 2 or 3 ). These approaches are more limited in their trauma to the extensor mechanism and have lower instances of Once the bone cuts have been made, and the prosthetic trials have been implanted, final soft-tissue balancing must be carefully completed and trial reductions are done to ensure adequate positioning, tacking and soft-tissue tension, stability and good patella tracking. The definitive devices are then implanted generally with cementless components. Wound closure is achieved with absorbable "vicryl" sutures and a suction drainage and skin closure with staples. A light gauze, cotton wool, and crepe dressing is applied during operation blood is aspirated through a blood filtration system (CELL-SAVER), this is continued during the next two post-operative hours so that to retransfuse the autologous blood (preventing any risk of blood disease transmission)
Surgical technique is an only one part of the success of TKA ; The role of superior pain management, better soft-tissue techniques, more advanced anesthetic techniques, more aggressive physiotherapy and perhaps, most importantly, improved patient education and enhanced rehabilitations are as important components in improving stability, function, component longevity, and patient satisfaction. You will stay 7 days in the surgical department of orthopaedics and then 14 days in the rehabilitation center.
Day of operation
The patients is mobilised at approximately 4 h post-op, under physiotherapist supervision. Straight leg raising exercises are encouraged, from a flexed position of the leg put on a pillow placed under the knee of the operated leg to allow the knee to rest in a fully flexed position. Analgesia shedule plan systems are adapted.
First postoperative day
Tensuring that pain level is well controlled, the patients undergoes further range of motion, quadriceps, and hamstrings exercises twice a day under control of the physiotherapist. Sitting and walking are started. CPM is used twice a day.
Second , third, fourth postoperative day
The dressing was reduced to a light non-adherent dressing, and the drainage removed. Walking with a 2 sticks is started. The patients continued to walk with the assistance of walking sticks. CPM is used twice a day. Active exercises are encouraged
Fifth and subsequent postoperative days
The patients is encouraged to climb steps, to roll skate while sitting, and to walk safely with two sticks and climb stairs independently.
Transfer to the rehabilitatin center where exercises of muscles reinforcement, and stability are performed. NB : a full physiological and functional recovery usually requires more than 2 months.
Even with a careful act performed by perfectly trained team, any complications may happen the same as in every surgical act. These are exceptional; The list below is not exhaustive.