An Unusual Failure of TKA: Surgical Considerations and Pain Management in the Revision Setting
Alexander Sah, MD
A pleasant 61-year-old female presents with a 2 year history of left knee pain. She had previously undergone uncomplicated left total knee replacement at an outside institution. She reports that she was doing well until she fell and broke her left hip in 2012, which was treated locally to her. She feels she has not walked well since that injury, and that her left knee symptoms worsened two years prior to presentation. She does not recall specific trauma. Her orthopaedic surgeon evaluated her, but no diagnosis was made. Overall, the pain has worsened in the past 3 months.
On a pain scale, the knee is rated an 8/10 and is constant. The pain is particularly bad with standing, walking, going up or down stairs, and twisting. The pain is located on the inside and front of the knee. The pain is described as sharp and she also complains of swelling, instability, and limping. She requires Tramadol for pain and other conservative treatment has included activity modification and knee bracing. She uses a walker for ambulation and is mostly housebound. She denies fevers, chills, or signs of infection.
Her past medical history is significant for depression, fibromyalgia, atrial fibrillation, kidney disease, and coronary artery disease. She takes eliquis for anticoagulation.
Patient is 5’3” and 235lbs, BMI of 41.6, in no acute distress. She is in a wheelchair and is unable to walk without a walker. She has a well-healed midline knee incision. The leg alignment is valgus, with moderate laxity to valgus/varus stress. There is a trace effusion with tenderness to palpation at the medial and lateral joint lines. Her passive knee range of motion is from 0-110 degrees, but there is a 15 degree active extension lag. Due to the size of the leg, it is difficult to assess anterior and posterior knee stability. Her motor, sensory, and vascular exams are intact distally.
Radiographs reveal an absence of space between the components on the AP view.
Her patella is tracking centrally.
A lateral knee X-ray shows a femoral component in an extended position with the anterior flange underneath the anterior femoral cortex.
There is more cement present adjacent to the femoral prosthesis than expected, suggesting a prior bone defect. The liner is seen disassociated from the tibial tray and dislocated anteriorly. The need for revision surgery was discussed with the patient. She understands that the dislocated liner requires revision. We discussed that while it is tempting to replace the liner only, there is a possibility that it may fail again if nothing else is revised. In addition, the malpositioned femoral component places her at risk for continued knee failure, or possible periprosthetic fracture. Furthermore, the suspected bone defects filled with prior cement may require additional stems or augments at time of revision. We also discussed the challenge of managing her postoperative pain given her history of fibromyalgia, pain medication use, and limitations due to existing kidney disease.
Preoperative workup was negative for infection by ESR and CRP, and intraoperative synovial fluid analysis, frozen section, and cultures were also negative. Upon exposure of the knee joint, the liner was protruding anteriorly. The liner was severely worn posteriorly. The suprapatellar pouch and medial and lateral gutters were re-established and debrided of inflamed synovium from poly debris. The femoral component was then exposed and its placement in extension was confirmed. The component was removed with care to preserve as much host bone as possible, but there was a large defect anteriorly from the notching of the index procedure and after removal of the prior cement. The tibia was then exposed and removed. There was significant lysis and loss of metaphyseal bone, which was more than expected based on the preop films. The cortex of the tibia was mostly intact and reasonably supportive.
The tibia was prepared for an intramedullary stem with hand reaming. A proximal tibial resection was then performed to establish proximal bone support. Because of the extent of metaphyseal bone loss, the tibia was prepared for a trabecular metal coupled tibial cone augment.
This provided improved proximal support of the component, maximizing contact to host bone. The femur was then prepared for a stemmed constrained component to bypass the anterior bone defect. Trial reductions were performed and there was appropriate knee motion and stability. A hybrid technique was used that cemented the components into place and a press-fit was used for the stems.
The tibial cone can be placed with or without cement, but was cemented in this case because of the quality of the host bone.
For pain management, intravenous Tylenol was used preoperatively. No NSAIDs were used because of her kidney and anticoagulation contraindications. A periarticular injection of Marcaine with epinephrine was performed for short-acting pain relief, and to possibly minimize bleeding. Liposomal bupivacaine was first injected throughout the posterior capsule, medial and lateral gutters, and periosteum. Because of the size of the patient and the revision exposure, 100ml of diluted injection was used; a large volume allows optimization to create as large of a field block as possible. A 22-guage needle was used to maximize infiltration so that the injection stays within the tissue. Finally, the remaining injection was used in the soft tissues and skin prior to closure.
The patient tolerated the surgery well. Her pain was well controlled and she was able to ambulate the day of surgery. She had an unremarkable hospital course. She was discharged home the second day after surgery. At her two week appointment her incision was healing well, her pain was much improved compared to the pain she felt pre-surgery, and she was ambulating with a cane. At her 6 week appointment she was taking no pain medications and was walking without an assist device.