Controversies in Knee Replacement: Techniques
At the ICJR South/RLO Course, expert faculty addressed total knee arthroplasty techniques that continue to elicit spirited debate and discussion among orthopaedic surgeons, including patella resurfacing, use of a tourniquet, and alignment.
Aaron G. Rosenberg, MD
Rush University Medical Center, Chicago, Illinois
Some areas of orthopaedic surgery do not have a standard of care, and according to Dr. Aaron Rosenberg, patella resurfacing during total knee arthroplasty (TKA) appears to be one of them.
He said there are several current issues regarding patella resurfacing:
- Should it be done?
- If it is done, when and how should it be done?
- Are there adjuncts to make resurfacing more effective?
- What are the sequelae of not resurfacing the patella?
International registry data do not show a consistent standard for resurfacing the patella, with a low of 2% of TKA procedures involving patella resurfacing in Norway to a high of 72% of the procedures done in Denmark.
The literature is mixed as well. Some studies show no difference in parameters such as functional outcomes, reoperation rates, revision rates, complications, and patient satisfaction between resurfaced and non-resurfaced patella groups. Others demonstrate an advantage to the resurfaced group for these parameters.
Click the image above to watch Dr. Rosenberg’s presentation.
Raymond H. Kim, MD
Colorado Joint Replacement, Denver
Finding limited research on the effects of tourniquet use in postoperative rehabilitation and functional recovery, Dr. Raymond Kim and his surgeon and physical therapy colleagues at the University of Colorado in Denver undertook a survey comparing recovery of quadriceps strength and lower extremity function in patients who underwent TKA with and without a tourniquet. Secondarily, they examined blood loss, postoperative pain, and lower extremity edema between groups.
To avoid between-group differences in demographics and medical comorbidities, Dr. Kim and his colleagues implemented the study in 28 patients undergoing simultaneous bilateral TKA, with one leg having a tourniquet in place for the entire procedure and the other leg having either no tourniquet or the tourniquet up only for cementing the implant.
The following outcome measures were assessed on POD2 and at 3 weeks and 3 months after surgery:
- Isometric quadriceps tourque
- Quadriceps activation test
- Unilateral balance test
- Active range of motion
- Lower extremity edema (thigh, knee, calf)
- Postoperative pain
- Intraoperative and postoperative blood loss
No statistically significant differences were seen between groups in most parameters, with the exception of quadriceps strength and pain – quadriceps strength was superior at 3 weeks and 3 months after surgery in the non-tourniquet group, and pain was decreased at 3 weeks in the non-tourniquet group.
There was also a trend favoring the non-tourniquet group for the quadriceps activation and unilateral balance tests, but follow-up was not long enough to determine if these would eventually be significant.
Click the image above to watch Dr. Kim’s presentation.
Gwo Chin-Lee, MD
University of Pennsylvania, Philadelphia
What is alignment in TKA? Dr. Gwo-Chin Lee said it’s a “loaded” term, complicated by traditional dogma based – perhaps erroneously – on short length radiographs and a procedure that cannot restore an anatomic, physiologically normal knee.
The good news is that despite these limitations, TKA is generally a successful, reproducible, and durable procedure that provides pain relief and restoration of function in most patients.
But TKA is not a perfect operation for every patient – about 20% are dissatisfied with the results, leaving surgeons wondering what they could do better.
Dr. Lee said that over the past few years, some surgeons have championed kinematic alignment over neutral mechanical alignment, with the goal of moving toward a more anatomic position of the implant and less kinematic mismatch. Short-term research has shown positive results with kinematic alignment.
This may solve the issues of the unhappy patients, but in reality, the long-term effects of this relatively new technique – such as contact stress and implant wear from joint line obliquity – are still unknown.
Dr. Lee has these takeaway points on alignment:
- The optimal alignment of the TKA remains unidentified.
- The concept of kinematic alignment merits further study.
- Small deviations from the conventional mechanical axis are safe.
- Refining the range/tolerance for long-term survivorship is needed.
Ultimately, he said, we don’t really know what makes a “perfect” TKA for an individual patient. He suspects alignment is only part of the equation.
Click the image above to watch Dr. Lee’s presentation.