Symposium: Papers Presented at the Annual Meetings of the Knee Society 149 articles
The 2012 Chitranjan Ranawat Award: Intraarticular Analgesia After TKA Reduces Pain: A Randomized, Double-blinded, Placebo-controlled, Prospective Study
Postoperative pain after total knee arthroplasty remains one of the most important challenges facing patients undergoing this surgery. Providing a balance of adequate analgesia while limiting the functional impact of regional anesthesia and minimizing opioid side effects is critical to minimize adverse events and improve patient satisfaction.
Knee stiffness or limited range of motion (ROM) after total knee arthroplasty (TKA) may compromise patient function. Patients with stiffness are usually managed with manipulation under anesthesia (MUA) to improve ROM. However, the final ROM obtained is multifactorial and may depend on factors such as comorbidities, implant type, or the timing of MUA.
Patient-specific instrumentation potentially improves surgical precision and decreases operative time in total knee arthroplasty (TKA) but there is little supporting data to confirm this presumption.
Fresh osteochondral allograft transplantation is an increasingly common treatment option for chondral and osteochondral lesions in the knee, but the long-term outcome is unknown.
Patient satisfaction has increasingly been recognized as an important measure after total knee arthroplasty (TKA). However, we do not know yet how and why the patients are satisfied or dissatisfied with TKA.
Surgical Technique: Vastus Medialis and Vastus Lateralis as Flap Transfer for Knee Extensor Mechanism Deficiency
Loss of the quadriceps tendon, patella, and patellar tendon leaves a major anterior defect that is difficult to close and compromises knee extension strength. Gastrocnemius muscle transfer does not sufficiently cover such major defects. This paper describes a new surgical technique that addresses these defects and the results of eight cases of revision TKA managed with this new technique.
Rotating-platform TKA, although purported to have superior kinematics, has shown no clinical advantages over those of fixed-bearing TKA. Our design-matched retrieval study aimed to investigate if differences in bearing wear damage exist between fixed- and mobile-bearing TKAs with similar condylar geometry.
Computer-assisted Total Knee Arthroplasty Is Currently of No Proven Clinical Benefit: A Systematic Review
Navigated total knee arthroplasty (TKA) may improve coronal alignment outliers; however, it is unclear whether navigated TKA improves the long-term clinical results of TKA.
Unicompartmental knee arthroplasty (UKA) has long been a treatment option for patients with disease limited primarily to one compartment with small, correctable deformities. However, some surgeons presume that normal kinematics of a lateral compartment UKA are difficult to achieve. Furthermore, it is unclear whether UKA restores normal knee kinematics and interlimb symmetry.
Computer-aided surgery aims to improve implant alignment in TKA but has only been adopted by a minority for routine use. A novel approach, navigated freehand bone cutting (NFC), is intended to achieve wider acceptance by eliminating the need for cumbersome, implant-specific mechanical jigs and avoiding the expense of navigation.
Computer navigation has improved accuracy and reduced the percentage of alignment outliers in TKA. However, the characteristics of outliers and the risk factors for limb malalignment after TKA are still unclear.
In a previously reported series of 51 patients with 62 cemented, fixed-bearing unicompartmental knee arthroplasties, we reported a 10-year, 98% survival rate with an average knee score of 92 points. The survivorship and modes of failure past 10 years are incompletely understood.
Can Microcomputed Tomography Measure Retrieved Polyethylene Wear? Comparing Fixed-bearing and Rotating-platform Knees
Wear of total knee polyethylene has been quantified gravimetrically with thickness measurements and evaluation of surface wear modes. However, these techniques do not localize volumetric wear.
TKA procedures are increasing rapidly, with substantial cost implications. Determining cost drivers in TKA is essential for care improvement and informing future payment models.
The ACL in the Arthritic Knee: How Often Is It Present and Can Preoperative Tests Predict Its Presence?
TKA with retention of the anterior cruciate ligament (ACL) may improve kinematics and function. However, conflicting reports exist concerning the prevalence of intact ACLs at the time of TKA.
Excessive alcohol consumption has been associated with adverse measures of health after elective surgery. However, associations of low/moderate consumption remain uncertain.
Despite the importance of complications in evaluating patient outcomes after TKA, definitions of TKA complications are not standardized. Different investigators report different complications with different definitions when reporting outcomes of TKA.
Low Risk of Thromboembolic Complications With Tranexamic Acid After Primary Total Hip and Knee Arthroplasty
The use of antifibrinolytic medications in hip and knee arthroplasty reduces intraoperative blood loss and decreases transfusion rates postoperatively. Tranexamic acid (TXA) specifically has not been associated with increased thromboembolic (TE) complications, but concerns remain about the risk of symptomatic TE events, particularly when less aggressive chemical prophylaxis methods such as aspirin alone are chosen.
The John Insall Award: No Benefit of Minimally Invasive TKA on Gait and Strength Outcomes: A Randomized Controlled Trial
While some clinical reports suggest minimally invasive surgical (MIS) techniques improve recovery and reduce pain in the first months after TKA, it is unclear whether it improves gait and thigh muscle strength.
Aligning patient and surgeon expectations preoperatively may lead to better postoperative medical and rehabilitation compliance and therefore improve outcomes and increase satisfaction.
High Infection Control Rate and Function After Routine One-stage Exchange for Chronically Infected TKA
Many surgeons consider two-stage exchange the gold standard for treating chronic infection after TKA. One-stage exchange is an alternative for infection control and might provide better knee function, but the rates of infection control and levels of function are unclear.
Prophylactic antibiotics reduce the risk of deep infection after primary TKA. However, conventional systemic dosing may not provide adequate tissue concentrations against more resistant organisms such as coagulase-negative staphylococci. Regional intravenous administration of antibiotics after tourniquet inflation achieves far higher tissue concentrations but requires foot vein cannulation. The intraosseous route may offer a rapid and reliable method of regional administration.
We observed isolated tibial component debonding from the cement in one modern primary TKA design (NexGen LPS 3° tibial tray; Zimmer, Warsaw, IN, USA). This failure mechanism is sparsely reported in the literature.
There is growing evidence to suggest many patients experience pain and dissatisfaction after TKA. The relationship between preoperative osteoarthritis (OA) severity and postoperative pain and dissatisfaction after TKA has not been established.
Local delivery of antifungals is an important modality in managing orthopaedic fungal infection. Voriconazole is a powder antifungal suitable for addition to bone cement that is released from bone cement but the mechanical properties of antimicrobial-loaded bone cement (ALBC) made with voriconazole are unknown.
Robotic-assisted TKA Reduces Postoperative Alignment Outliers and Improves Gap Balance Compared to Conventional TKA
Several studies have shown mechanical alignment influences the outcome of TKA. Robotic systems have been developed to improve the precision and accuracy of achieving component position and mechanical alignment.
Modular tibial trays have been utilized in TKA for more than 20 years. However, concerns have been raised about modular implants and it is unclear whether these devices are durable in the long term.
The 2012 Mark Coventry Award: A Retrieval Analysis of High Flexion versus Posterior-stabilized Tibial Inserts
High flexion (HF) implants were introduced to increase ROM and patient satisfaction, but design changes to the implant potentially have deleterious effects on polyethylene wear. It is unclear whether the HF implants affect wear.
Irrigation and débridement (I&D) of periprosthetic infection (PPI) is associated with infection control ranging from 16% to 47%. Mitigating factors include organism type, host factors, and timing of intervention. While the influence of organism type and host factors has been clarified, the timing of intervention remains unclear.
Administrative claims data are increasingly being used in public reporting of provider performance and health services research. However, the concordance between administrative claims data and the clinical record in lower extremity total joint arthroplasty (TJA) is unknown.
The Knee Society Clinical Rating System was developed in 1989 and has been widely adopted. However, with the increased demand for TKA, there is a need for a new, validated scoring system to better characterize the expectations, satisfaction, and physical activities of the younger, more diverse population of TKA patients.
Assessment of patient function after TKA often focuses on implant alignment and daily activity capabilities, but the functional results and kinematics of the TKA are not easily predicted by some of these parameters during surgery.
TKA and unicompartmental knee arthroplasty (UKA) are both utilized to treat unicompartmental knee arthrosis. While some surgeons assume UKA provides better function than TKA, this assumption is based on greater final outcome scores rather than on change in scores and many patients with UKA have higher preoperative scores.
Modular, metal-backed tibial (MBT) components are associated with locking mechanism dysfunction, breakage, backside wear, and osteolysis, which compromise survivorship. All-polyethylene tibial (APT) components eliminate problems associated with MBTs, but, historically, APT utilization has generally been limited to older, less active patients. However, it is unclear whether APT utilization can be expanded to a nonselected patient population.
TKA provides demonstrable pain relief and improved health-related quality of life. Yet, a decline in physical function may occur over the long term despite the absence of implant-related problems.
Does a Modified Gap-balancing Technique Result in Medial-pivot Knee Kinematics in Cruciate-retaining Total Knee Arthroplasty?: A Pilot Study
Normal knee kinematics is characterized by posterior femorotibial rollback with tibial internal rotation and medial-pivot rotation in flexion. Cruciate-retaining TKAs (CR-TKAs) do not reproduce normal knee kinematics.
Mobile bearing (MB) total knee design has been advocated as a means to enhance the functional characteristics and decrease the wear rates of condylar total knee arthroplasty (TKA). However, it is unclear if these designs achieve these goals.
Perioperative Closure-related Complication Rates and Cost Analysis of Barbed Suture for Closure in TKA
The use of barbed suture for surgical closure has been associated with lower operative times, equivalent wound complication rate, and comparable cosmesis scores in the plastic surgery literature. Similar studies would help determine whether this technology is associated with low complication rates and reduced operating times for orthopaedic closures.
Can a High-flexion Total Knee Arthroplasty Relieve Pain and Restore Function Without Premature Failure?
High-flexion TKA prostheses are designed to improve flexion and clinical outcomes. Increased knee flexion can increase implant loads and fixation stresses, creating concerns of premature failure. Whether these goals can be achieved without premature failures is unclear.
Deep infections are devastating complications of TKA often treated with component explantation, intravenous antibiotics, and antibiotic-impregnated cement spacers. Historically, the spacers have been static, which may limit patients’ ROM and ability to walk. Several recent reports describe dynamic spacers, which may allow for improved ROM and make later reimplantation easier. However, because of several dynamic spacer problems noted at our institution, we wanted to assess their associated failures, reinfection rates, and functionality.
Studies have demonstrated sex differences in femoral shape and quadriceps angle raising a question of whether implant design should be sex-specific. Much of this research has addressed shape differences within the Caucasian population and little is known about differences among ethnic groups.
Revision of failed two-stage revision TKA for infection is challenging, and amputation often is the only alternative.
Patient-related Risk Factors for Postoperative Mortality and Periprosthetic Joint Infection in Medicare Patients Undergoing TKA
The impact of specific baseline comorbid conditions on the relative risk of postoperative mortality and periprosthetic joint infection (PJI) in elderly patients undergoing TKA has not been well defined.
Is There a Preferred Articulating Spacer Technique for Infected Knee Arthroplasty?: A Preliminary Study
Periprosthetic infection in TKA is a devastating and challenging problem for both patients and surgeons. Two-stage exchange arthroplasty with an interval antibiotic spacer reportedly has the highest infection control rate. Studies comparing static spacers with articulating spacers have reported varying ROM after reimplant, which could be due to differences in articulating spacer technique.
Routine patellar resurfacing performed at the time of knee arthroplasty is controversial, with some evidence of utility in both TKA (tricompartmental) and bicompartmental knee arthroplasty. However, whether one approach results in better implant survival remains unclear.
Can Surgeons Predict What Makes a Good TKA?: Intraoperative Surgeon Impression of TKA Quality Does Not Correlate With Knee Society Scores
Surgeons generally agree on what they want to achieve when performing TKA. However, we do not know which technical quality goals are correct, important, or irrelevant to achieve adequate function or durability.
Lateral Unicompartmental Knee Arthroplasty Through a Lateral Parapatellar Approach Has High Early Survivorship
The literature suggests lateral unicompartmental knee arthroplasties are associated with low revision rates. However, there are fewer reports describing techniques for lateral unicompartmental arthroplasty and whether technique influences ROM and function compared to reports for medial unicompartmental arthroplasty.
Options to treat patients with wear or osteolysis include full revision, partial (tibial or femoral) revision, and isolated polyethylene exchange. It is unclear whether one choice is superior to the other. Polyethylene quality reportedly influences the survivorship of primary TKA, but similar reports are not described for revision TKA.
Improved Accuracy of Alignment With Patient-specific Positioning Guides Compared With Manual Instrumentation in TKA
Coronal malalignment occurs frequently in TKA and may affect implant durability and knee function. Designed to improve alignment accuracy and precision, the patient-specific positioning guide is predicated on restoration of the overall mechanical axis and is a multifaceted new tool in achieving traditional goals of TKA.
Restoring patellar height is important in revision TKA for normal knee function and kinematics. Alteration in patellar height after revision TKA is associated with inferior extensor mechanism function.
Mark B. Coventry Award: Synovial C-reactive Protein: A Prospective Evaluation of a Molecular Marker for Periprosthetic Knee Joint Infection
C-reactive protein (CRP) serum assays are a standard element of the diagnostic workup for periprosthetic joint infection (PJI). However, because CRP is a marker for systemic inflammation, this test is not specific to PJI.
Numerous reports suggest the application of platelet-rich plasma (PRP) during TKA may decrease postoperative bleeding. Because excessive bleeding can increase postoperative pain and inflammation, use of PRP also reportedly decreases the need for narcotics and increases speed of recovery after TKA. Because previous investigations of PRP and TKA reflect a weak level of medical evidence, we sought to confirm these findings.
All-Polyethylene Tibial Components in Obese Patients Are Associated With Low Failure at Midterm Followup
In the United States, the obese population has increased markedly over the last four decades, and this trend continues. High patient weight places additional stress on TKA components, which may lead to increased polyethylene wear, osteolysis, radiolucencies, and clinical failure. Metal-backed tibial components and all-polyethylene tibial components in the general population have comparable osteolysis and failure, but it is unclear whether these components yield similar osteolysis and failure in obese patients.
Lateral Unicompartmental Knee Arthroplasty Relieves Pain and Improves Function in Posttraumatic Osteoarthritis
Posttraumatic arthritis secondary to lateral tibial plateau fracture malunion causes pain and limited function for patients. It is sometimes technically challenging to correct malalignment in these patients with advanced arthritis using osteotomies. Lateral unicompartmental knee arthroplasty (UKA) may be an option to treat such patients.
Early studies in the literature reported relatively high early minor reintervention rate for the mobile-bearing unilateral knee arthroplasty (UKA) compared with short- and midterm survivorship after fixed- or mobile-bearing UKA. However, whether the long-term function and survivorship are similar is unclear.
Decreased Length of Stay After TKA Is Not Associated With Increased Readmission Rates in a National Medicare Sample
There is a trend toward decreasing length of hospital stay (LOS) after TKA although it is unclear whether this trend is detrimental to the overall postoperative course. Such information is important for future decisions related to cost containment.
Inpatient hospital falls after orthopaedic surgery represent a major problem, with rates of about one to three falls per 1000 patient days. These falls result in substantial morbidity for the patient and liability for the institution.
The Chitranjan Ranawat Award: Is Neutral Mechanical Alignment Normal for All Patients?: The Concept of Constitutional Varus
Most knee surgeons have believed during TKA neutral mechanical alignment should be restored. A number of patients may exist, however, for whom neutral mechanical alignment is abnormal. Patients with so-called “constitutional varus” knees have had varus alignment since they reached skeletal maturity. Restoring neutral alignment in these cases may in fact be abnormal and undesirable and would likely require some degree of medial soft tissue release to achieve neutral alignment.
The best method for managing large bone defects during revision knee arthroplasty is unknown. Metaphyseal fixation using porous tantalum cones has been proposed for severe bone loss. Whether this approach achieves osseointegration with low complication rates is unclear.
Aseptic loosening and periprosthetic osteolysis resulting from wear debris are major complications of total joint arthroplasty. Monocyte/macrophages are the key cells related to osteolysis at the bone-implant interface of joint arthroplasties. Whether the monocyte/macrophages found at the implant interface in the presence of polyethylene particles are locally or systemically derived is unknown.
A dramatic increase in the demand for TKA is expected. The current burden of revision TKA is well known but the incidence and etiology of nonrevision reoperations after primary TKA is not.
Mobile-bearing TKAs reportedly have no clinical superiority over fixed-bearing TKAs, but a potential benefit is improved polyethylene wear behavior.
The contribution provided by the popliteus tendon in patients undergoing TKA is poorly defined. Some authors believe the popliteus tendon is essential to a well-functioning arthroplasty, while others do not believe it provides a critical function.
Liner exchange and bone grafting are commonly performed for wear and osteolysis around well-fixed modular acetabular components that otherwise would require structural allografting and revision THA. However, liner exchange in the face of substantial lysis around TKA has been performed rarely with reports of failure rates of up to 25% at 3 year followup.
In vivo studies have suggested Caucasians achieve lower average knee flexion than non-Western populations. Some previous studies have also suggested gender may influence condylar AP translation and axial rotation, while others report an absence of such an influence.
Total knee arthroplasty (TKA) in patients with skeletal dysplasias is particularly challenging as a result of the anatomic variances and substantial bony deformities. Little has been written regarding technical considerations that should be made when performing TKA in skeletal dysplasia.
The tibial post in posterior-stabilized total knees is a potential source of polyethylene wear debris, but the relationship between the shape and location of the tibial post in relation to the tibiofemoral bearing surfaces and the subsequent wear damage patterns remains unknown.
Patients with a personal or familial history of thromboembolism are considered at higher risk for thromboembolic disease after knee arthroplasty. While it remains unclear why some patients develop deep vein thrombosis (DVT) or pulmonary embolism (PE) despite similar operative procedures and the same prophylactic regimen, we presume one explanation would be genetic predisposition.
After right total knee arthroplasty (TKA), patients are usually eager to return to driving. Previous studies suggest 6 weeks postsurgery is a safe time. However, recent advances in surgical technique, pain management, and rehabilitation have theoretically improved recovery after TKA.
The role of unicompartmental arthroplasty in managing osteoarthritis of the knee remains controversial. The Oxford medial unicompartmental arthroplasty employs a fully congruent mobile bearing intended to reduce wear and increase the lifespan of the implant. Long-term second decade results are required to establish if the design aim can be met.
Intraoperative injuries to the medial collateral ligament are often unrecognized and failure to appropriately manage ligament loss may result in knee instability and loosening.
Knee Arthroplasty With a Medially Conforming Ball-and-Socket Tibiofemoral Articulation Provides Better Function
A knee design with a ball-and-socket articulation of the medial compartment has a femoral rollback profile similar to the native knee. Compared to a conventional, posterior-stabilized knee design, it provides AP stability throughout the entire ROM. However, it is unclear whether this design difference translates to clinical and functional improvement.
The complication risk of staged versus simultaneous total knee arthroplasty continues to be debated in the literature. Previous reports suggest unicompartmental knee arthroplasty provides a more rapid functional recovery than total knee arthroplasty. However, little data exist on whether simultaneous unicompartmental knee arthroplasty can be performed without increasing the perioperative risk compared with staged unicompartmental knee arthroplasty.
Wear of polyethylene tibial inserts can decrease the longevity of total knee arthroplasty. Wear is currently assessed using laboratory methods that may not permit backside wear measurements or do not quantify surface deviation.
The hospital cost of total knee arthroplasty (TKA) in the United States is a major growing expense for the Centers for Medicare & Medicaid Services (CMS). Many hospitals are unable to deliver TKA with profitable or breakeven economics under the current Diagnosis-Related Group (DRG) hospital reimbursement system.
The John Insall Award: Control-matched Evaluation of Painful Patellar Crepitus After Total Knee Arthroplasty
Patellar crepitus (PC) is reported in up to 14% of subjects implanted with cruciate-substituting total knee arthroplasty (TKA). Numerous etiologies of PC have been proposed.
Do “Premium” Joint Implants Add Value?: Analysis of High Cost Joint Implants in a Community Registry
Numerous joint implant options of varying cost are available to the surgeon, but it is unclear whether more costly implants add value in terms of function or longevity.
The Chitranjan Ranawat Award: Fate of Two-stage Reimplantation After Failed Irrigation and Débridement for Periprosthetic Knee Infection
Irrigation and débridement is an attractive low morbidity solution for acute periprosthetic knee infection. However, the failure rate in the literature is high, averaging 68% (range, 61%–82%). Patients who fail subsequently undergo two-stage reimplantation after a prolonged period of illness. This leads to higher surgical risk and further delays in rehabilitation and may contribute to failure of subsequent revision surgery.
The Mark Coventry Award: Diagnosis of Early Postoperative TKA Infection Using Synovial Fluid Analysis
Synovial fluid white blood cell count is useful for diagnosing periprosthetic infections but the utility of this test in the early postoperative period remains unknown as hemarthrosis and postoperative inflammation may render standard cutoff values inaccurate.
The femoral peel to expose a difficult knee was first described by Windsor and Insall in the mid-1980s. This surgical exposure consists of a complete soft tissue subperiosteal peel of the femur. It includes the detachment of the origin of the medial and lateral collateral ligaments.
Most long-term followup studies of younger patients who underwent TKA include a relatively high percentage of rheumatoid patients, whose function and implant durability may differ from those with osteoarthritis (OA).
Methicillin-resistant Staphylococcus aureus in TKA Treated With Revision and Direct Intraarticular Antibiotic Infusion
Resistant organisms are difficult to eradicate in infected total knee arthroplasty. While most surgeons use antibiotic-impregnated cement in these revisions, the delivery of the drug in adequate doses is limited in penetration and duration. Direct infusion is an alternate technique.