Julio J. Jauregui

Mechanical, Anatomical, and Kinematic Axis in TKA: Concepts and Practical Applications

Successful total knee arthroplasty (TKA) has often been based on the restoration of the knee to neutral alignment postoperatively. Numerous reports have linked malaligned TKA components to increased wear, poor functional outcomes, and failure. There have been many different alignment philosophies and surgical techniques that have been established to attain the goal of proper alignment, which includes such techniques as computerized navigation, and custom cutting guides. In addition, these methods could potentially have the added benefit of leading to improved functional outcomes following total knee arthroplasty. In this report, we have reviewed and analyzed recent reports concerning mechanical, anatomic, and kinematic axis/alignment schemes used in total knee arthroplasty.

Dual mobility cups: an effective prosthesis in revision total hip arthroplasties for preventing dislocations

Purpose Postoperative dislocation is one of the most common complications following total hip arthroplasty (THA), and dual mobility articulations have been designed to provide greater hip stability. However, there are few studies that have assessed outcomes of these designs in revision THAs. Our purpose was to evaluate differences in dislocation rates, aseptic survivorship, and patient outcomes between dual mobility articulations and conventional arthroplasties in the revision setting. Methods Patients who underwent revision THA with dual mobility articulations (n = 60) were matched (1:2) to patients who had conventional single articulation prostheses (n = 120). They were matched for body mass index, age, gender, and Paprosky acetabular defect classification, and were followed up for a mean of 30 months (range, 18 to 52 months). The outcomes were evaluated preoperatively and at final follow-up using Harris Hip Scores, the University of California Los Angeles activity scale, and the Short Form-36 questionnaires. Results The dual mobility group had lower dislocation (1.7% (1 out of 60) versus 5.8% (7 out of 120)) and aseptic loosening rates (1.7% (1 out of 60) versus 4.2% (5 out of 120)) compared to the control group. There were no significant differences in functional outcomes, activity level, or overall physical and mental health status between the 2 cohorts. Conclusions When used in the revision setting, dual mobility bearings had fewer dislocations. We believe that these designs may lead to clinically significant improvements in complications while also improving patient reported and functional outcomes, but larger cohort studies are necessary for evaluation.

Osteonecrosis of the knee: review

Osteonecrosis is a devastating disease that can lead to end-stage arthritis of various joint including the knee. There are three categories of osteonecrosis that affect the knee: spontaneous osteonecrosis of the knee (SONK), secondary, and post-arthroscopic. Regardless of osteonecrosis categories, the treatment of this disease aims to halt further progression or delay the onset of end-stage arthritis of the knee. However, once substantial joint surface collapse has occurred or there are sign of degenerative arthritis, joint arthroplasty is the most appropriate treatment option. Currently, the non-operative treatment options consist of observation, non-steroidal anti-inflammatory drugs (NSAIDs), protected weight bearing, and analgesia as needed. Operative interventions include joint preserving surgery, unilateral knee arthroplasty (UKA), or total knee arthroplasty (TKA) depending on the extent and type of disease. Joint preserving procedures (i.e., arthroscopy, core decompression, osteochondral autograft, and bone grafting) are usually attempted in pre-collapse and some post-collapse lesions, when the articular cartilage is generally intact with only the underlying subchondral bone being affected. Conversely, after severe subchondral collapse has occurred, procedures that attempt to salvage the joint are rarely successful and joint arthroplasty are necessary to relieve pain. The purpose of this article is to highlight the recent evidence concerning the treatment options across the spectrum of management of osteonecrosis of the knee including lesion observation, medications, joint preserving techniques, and total joint arthroplasties.

Cementless Total Knee Arthroplasty: A Review

There is ongoing debate over the use of cementless fixation in total knee arthroplasty (TKA). Previous generation prostheses resulted in less than optimal outcomes which was somewhat attributed to design issues. As the demand for TKA is continuously increasing and the current U.S. age population is getting younger, cemented fixation may not provide adequate long-term outcomes due to failure of fixation. Thus, there has been a reemergence of the development and use of cementless TKA. Recent short-term trials have demonstrated that modern cementless TKA has comparable survivorship and functional outcomes as cemented prostheses. However, more prospective, randomized trials are needed to clearly delineate any differences between these two fixation options.

Long-Term Survivorship and Clinical Outcomes Following Total Knee Arthroplasty

Total knee arthroplasty (TKA) is one of the most successful commonly performed orthopedic procedures; as such, the purpose was to assess the long-term outcomes and survivorship of primary TKAs with a dual-radius prosthesis. We evaluated 125-patients (145-knees), with a mean age of 63 years (37-90 years) for a mean 11-year follow-up (10-13 years). Outcomes were assessed with KSS, UCLA, SF-36, satisfaction scores, and aseptic survivorship analysis. At 10-year follow-up, the UCLA (6-points), KSS objective (84-points) and functional (73-points), SF-36 physical (41-points) and mental (51-points), and patient satisfaction (14-points) scores were reported to be good to excellent. The 10-year Kaplan-Meier survivorship rate was 99%; one TKA demonstrated radiographic loosening. At a minimum 10-year follow-up, this device demonstrated satisfactory outcomes and outstanding aseptic-survivorship rates.

Bicruciate-retaining total knee arthroplasty: a review.

Total knee arthroplasty (TKA) has been shown to have excellent long-term outcomes and survivorship in numerous studies, however, with changes in patient demographics, questions have arisen about the use of conventional arthroplasties and their functionality in highly active, young patients. The recent interest in bicruciate-retaining prostheses is aimed to address the need for an implant that can mimic a natural knee during high activity levels. Although there are currently few of these prostheses which are being utilized, results from prior studies have demonstrated similar results to that of anterior cruciate ligament-sacrificing TKA in terms of function and survivorship. In this review, we will describe the history, kinematics, clinical outcomes, concerns, and future outlook of bicruciate-retaining arthroplasty.

New and Common Perioperative Pain Management Techniques in Total Knee Arthroplasty

Optimal pain control in patients undergoing total knee arthroplasty (TKA) is imperative for good rehabilitation and functional outcomes. However, despite technological advancements, surgeons continue to struggle with adequate pain management in their patients. Current modalities in use, such as patient-controlled analgesia, opioids, and epidural anesthetics, provide good pain relief but can be associated with side effects and serious complications. As a result, newer pain control modalities have been used to try to reduce the use of opioids while providing adequate pain relief. Currently, there are no clear guidelines or evidence for an optimum postoperative TKA analgesic regimen. Our aim was to evaluate the recent literature and provide a summary of the newer perioperative analgesic modalities. Evidence suggests that analgesics, such as newer oral medications, peripheral nerve blocks, and periarticular injections, may improve pain management, rehabilitation, and patient satisfaction, as well as reduce opioid consumption. The literature has also highlighted that a multimodal approach to pain management may provide the best results. However, determining which modalities provide superior pain control is still being extensively studied, and further research is needed.

A Prospective, Longitudinal Study of Outcomes Following Total Knee Arthroplasty Stratified by Gender

This study aimed to compare temporal trends in outcomes between men and women following TKA. A database of 272 TKAs at 7 years follow-up were evaluated for survivorship, functional, activity, and quality of life outcomes. Evaluation of implant survivorship, KSS scores, and ROM showed no significance differences between men and women, but both functional KSS scores and LEAS showed that men had significantly higher functional scores. The SF-36 physical component was found to be significantly better in men at multiple time points, whereas, the mental component was significantly better in men at pre-operative and 2 years. Both men and women benefit from TKA, however, men have higher levels of function and activity both prior to and after TKA than women.

Does Preadmission Cutaneous Chlorhexidine Preparation Reduce Surgical Site Infections After Total Knee Arthroplasty

BackgroundMany preventive methodologies seek to reduce the risk of surgical site infections after total knee arthroplasty (TKA), including the use of preoperative chlorhexidine baths and cloths. Although we have demonstrated in previous studies that this may be an efficacious method for infection prevention, our study was underpowered and we therefore set out to evaluate this with a larger sample size.Questions/purposes(1) Does a preadmission chlorhexidine cloth skin preparation protocol decrease the risk of surgical site infection in patients undergoing TKA? (2) When stratified using the National Healthcare Safety Network (NHSN) risk categories, which categories are associated with risk reduction from the preadmission chlorhexidine preparation protocol?MethodsIn our study, all patients (3717 total) who had undergone primary or revision TKA at a single institution between January 1, 2007, and December 31, 2013, were identified, of whom 991 patients used the chlorhexidine cloths before surgery and 2726 patients did not. All patients were provided cloths with instructions before surgery; however, as a result of a lack of compliance, we were able to substratify patients into treatment and control cohorts. Additionally, we substratified patients by NHSN risk category to determine differences in infection between the two cohorts (cloth versus no cloth). Patient medical records and an infection-tracking database were reviewed to determine the development of periprosthetic infection (patients who had superficial infections were excluded from our study) in both groups after 1 year surveillance. We then calculated relative risk reductions with use of chlorhexidine gluconate and stratified results based on NHSN risk category.ResultsUse of a preoperative chlorhexidine cloth skin preparation protocol is associated with reduced relative risk of periprosthetic infection after TKA (infections with protocol: three of 991 [0.3%]; infections in control: 52 of 2726 [1.9%]; relative risk [RR]: 6.3 [95% confidence interval [CI], 1.9–20.1]; p = 0.002). When stratified by NHSN risk category, periprosthetic infection risk reduction was seen in the medium-risk category (protocol: one of 402 [0.3%]; control: 25 of 1218 [2.0%]; RR, 8.3 [CI, 1.1–60.7]; p = 0.038), but no significant difference was detected in the low- and medium-risk groups (RR, 2.1 [CI, 0.5–9.6; p = 0.33] and RR, 11.3 [CI, 0.7–186.7; p = 0.09]).ConclusionsA prehospital chlorhexidine gluconate wipe protocol appears to reduce the risk of periprosthetic infections after TKA, primarily in those patients with medium and high risk. Although future multicenter randomized trials will need to confirm these preliminary findings, the intervention is inexpensive and is unlikely to be risky and therefore might be considered on the basis of this retrospective, comparative study.Level of EvidenceLevel III, therapeutic study.

Robotic-assisted knee arthroplasty.

Robotics in total knee arthroplasty (TKA) has undergone vast improvements. Although some of the systems have fallen out of favor due to safety concerns, there has been recent increased interest for semi-active haptic robotic systems that provide intraoperative tactile feedback to the surgeon. The potential advantages include improvements in radiographic outcomes, reducing the incidence of mechanical axis malalignment of the lower extremity and better tissue balance. Proponents of robotic technology believe that these improvements may lead to superior functional outcomes and implant survivorship. We aim to discuss robotic technology development, outcomes of unicompartmental and total knee arthroplasty and the future outlook. Short-term follow-up studies on robotic-assisted knee arthroplasty suggest that, although some alignment objectives may have been achieved, more studies regarding functional outcomes are needed. Furthermore, studies evaluating the projected cost–benefit analyses of this new technology are needed before widespread adoption. Nevertheless, the short-term results warrant further evaluation.