Fred D. Cushner's research while affiliated with Hospital for Special Surgery and other places

Background Since the COVID-19 pandemic of 2020, there has been a marked rise in the use of telemedicine to evaluate patients after total knee arthroplasty (TKA). The purpose of our study was to assess a novel stem with an embedded sensor that can remotely and objectively monitor a patient’s mobility after TKA. Methods A single anatomically designed knee system was implanted in concert with an interconnected tibial stem extension containing 3D accelerometers, 3D gyroscopes, a power source, and a telemetry transmission capability in 3 cadaveric pelvis to toe specimens. The legs were moved by hand to preset tibial positions at full knee extension, midflexion, flexion, and back to midflexion and extension for a total of 16 trials across 6 knees. Results Sensor data were successfully transmitted with good quality of signal to an external base station. Good correlation to the range of motion of the tibia was found (mean error 0.1 degrees; root mean square error 3.8 degrees). The signal from the heel drop tests suggests the sensor could detect heel strike during activities of daily living in vivo and the potential for additional signal processing to analyze vibratory and motion patterns detected by the sensors. A frequency domain analysis of a properly cemented and poorly cemented implant during the heel drop test suggests a difference in accelerometer signal in these implant states. Conclusion The results confirm signals generated from an embedded TKA sensor can transmit through bone and cement, providing accurate range of motion data and may be capable of detecting changes in prosthesis fixation remotely.

As the number of total knee arthroplasty surgeries exponentially rise over the next decade, there will be a parallel rise in the complications observed. Patients who undergo total knee arthroplasties will be at an increased risk for postoperative anemia and allogenic blood transfusions (ABTs). The range of complications associated with perioperative anemia and ABTs include increased length of stay (LOS) in the hospital, increased surgical site infections/periprosthetic joint infections, and mortality. There are many perioperative blood conservation strategies that can be utilized to help optimize a patient, prevent excessive bleeding, and reduce the need for possible ABTs. Although there is extensive research on this topic, there is a lack of consensus on the best strategy to help prevent perioperative anemia and the complications associated with it. Surgeons should be able to recognize perioperative anemia and utilize the information in this section to prevent its unnecessary complications.

Despite the success of total knee arthroplasty (TKA), more than 20,000 revision TKA procedures are performed annually. In an effort to decrease failures due to loosening in the past, cementless fixation of TKA was suggested. The preliminary results of cementless fixation for TKA proved to be discouraging, with midterm results linking the use of uncemented components to early aseptic loosening. While cemented TKA has remained the gold standard fixation technique, the changing demographics of the average TKA patient have led some surgeons to revisit cementless fixation as an option.

Background: Wound complications associated with soft tissue defects following total knee arthroplasty present challenges for the orthopedic surgeon. The scale of early complications include less morbid problems, such as quickly resolving drainage and small superficial eschars, to persistent drainage and full-thickness tissue necrosis, which may require advanced soft tissue coverage. Methods: This review outlines current wound management strategies and provides an algorithm to help guide treatment and clinical decision-making. Conclusion: A surgeon's understanding of soft tissue coverage options is essential in protecting the knee prosthesis from a deep infection and to obtain an optimal functional outcome.

Total knee arthroplasty (TKA) is recognized as one of the most successful surgical procedures performed today. One of the most common and dreaded complications of TKA is postoperative infection. To prevent infections, it is critical to identify patients at high risk through analyzing their risk factors, and help in addressing them prior to surgery. The effort to prevent infection must be carried through every step of the surgical process, from preoperative counseling to intraoperative measures and postoperative protocols. Hair removal, the application of antiseptics, the utilization of antibiotics, barbed sutures, smart dressings, and antibacterial washes are some of the avenues surgeons may explore to help prevent infection.

Obesity has become a major problem for the treatment of arthritis of the knee. The patients have multiple comorbidities that contribute to the perioperative increase in complications, and the surgical exposure, itself, is far more difficult than the normal size knee joint. The preoperative evaluation must be thorough to expose any and all associated medical problems, and the patient should be optimized as thoroughly as possible. The surgical procedure demands proper exposure, and the choice of the implant may need to be modified to protect the prosthetic device from subsequent loosening.

The success of partial knee arthroplasty is well described in the literature. Both mobile-bearing knee and fixed-bearing knee designs have good long-term survivorship described in the literature. While long-term success is well described, there is still a certain amount of failures that are noted and revision of this partial knee is required. Because only a partial knee is performed, one could argue that there is inherent risk of revision for the unhappy patient. For example, a TKA patient with anterior knee pain may be sent to physical therapy, told to lose weight, and prescribed some activity modification. Given the nature of a full revision, it is often done only as a last resort. But if you take the same patient with anterior knee pain who had a partial knee arthroplasty at their indicated procedure, then it is often claimed that this patient is more likely to get revised. Perhaps it would be revised because of the unresurfaced patella or perhaps revised cause the patient is unhappy, but it often does appear to be a double standard when it comes to revision of partial knee arthroplasty.

It is not uncommon for patients to describe a stiff knee in the immediate postoperative period. While they believe their knee is “stiff,” often these stiff knees have ROM of greater than 120° flexion. For the sake of discussion, this discussion will focus on knees with less than 90° of flexion in the immediate postoperative period. Lotke et al. were a bit more restrictive in their definition of stiffness. They considered a knee stiff if there was greater than a15° flexion contracture and less than 75° of motion. With this definition, an overall incidence in over 1000 consecutive knees was 1.3%. As expected limited preoperative ROM was more likely to have postoperative limitations in this series.

Patellofemoral arthroplasty has become more common over the last decade. Perhaps this increase is related to advances in technology. It is now much easier to perform a successful patellofemoral arthroplasty.