Unicondylar Knee Arthroplasty Made Simple.

Unicompartmental knee arthroplasty (UKA) has become an increasingly used procedure for patients with unicompartmental knee osteoarthritis. The success of UKA relies on appropriate patient selection and patient optimization before surgery is performed. Improved prosthesis design and surgical techniques for medial and lateral and fixed and mobile bearing UKA have also contributed to improved knee biomechanics, faster recovery, and improved outcomes. Indications, factors affecting patient selection, the role of limb alignment, and the surgical pearls for fixed and mobile bearing and medial and lateral UKA are important topics for discussion.

Hot Topics and Current Controversies in Total Knee Arthroplasty.

Total knee arthroplasty continues to evolve. It is important to review some of the current controversies and hot topics in arthroplasty. Optimal knee alignment strategy is now just a matter of debate. Mechanical, kinematic, and functional alignment and the role of robotics in achieving optimum alignment are important topics, along with fixation and outpatient knee arthroplasty.

The Natural History of Radiolucencies Following Uncemented Total Knee Arthroplasty at 9 Years.

BACKGROUND: Aseptic loosening remains a common cause of failure in total knee arthroplasty (TKA). There is an increased interest in using uncemented TKA to reduce this complication. Radiolucencies (RLs) following uncemented TKA can be concerning. We report on the 9-year history of RLs in patients with uncemented TKA. METHODS: Twenty-one patients (26 knees) were treated with a cruciate-retaining fully porous coated femur/tibia and cemented patella. At final follow-up, 17 patients (22 knees) were available for review. Average follow-up was 9.6 years, average age was 59.1, and average body mass index was 34.1. X-rays were taken at 6 weeks, 1 year, and at final follow-up. RLs were measured using the Knee Society scoring system and read by two separate surgeons. RESULTS: At 6 weeks, we identified RL in all patients on both the tibia and femur. The majority were beneath the tibial tray and femoral chamfer. At 1 year, 4 femurs and 4 tibias showed new RLs (<2 mm) in similar zones. Eighteen femurs and 18 tibias showed fewer or no change in RLs. At final follow-up, no new tibia or femur developed a new RL. In total, 9 of the 22 tibias and 17 of the 22 femurs had remaining RLs, all less than 2 mm and none were progressive or new. Knee Society Score averaged 92.5 (6 weeks), 95.1 (1 year), and 97.3 (final). CONCLUSION: RLs are common following uncemented TKA. Many resolve by 1 year. There does not appear to be any association between the presence of RLs and long-term follow-up function in this group of patients.

Ignore the Patella in Revision Total Knee Surgery: A Minimum 5-Year Follow-Up With Patella Component Retention.

BACKGROUND: In the setting of aseptic revision, a common question is: what should be done with the previously resurfaced patella? We report on a series of aseptic revision total knee arthroplasties (RTKA) where one or both components were revised and the patella was not. METHODS: The study group was 147 consecutive RTKA in 137 patients with a mean age of 70.1 ± 9.3 years where the patella was not revised. The average body mass index was 31.0 ± 5.4 kg/m2. Follow-up was a minimum of 5 years (range, 5 to 12 years). At final follow-up, 13 patients died and 2 patients were lost to follow-up leaving 122 patients and 130 knees available for review. Mean time from primary surgery to RTKA was 9.2 ± 5.5 years. Both components were revised in 50 knees, the femur only in 11 knees, the tibia only in 12 knees, and 57 had an isolated polyethylene revision. We found 5 patients with a mismatch between the patella and femoral components and 30 cases with patella component wear identified intraoperatively. RESULTS: At final follow-up, there were no reoperations on any patella and none were at risk of failure. There were 6 knees with a lateral patella tilt beyond 10°, but none were subluxed. Knee Society Scores averaged 85 ± 17.2 points at final follow-up. CONCLUSION: At midterm follow-up in this group of RTKA where the patella was not revised, we identified no subsequent failures of the patella. This is despite the presence of mild patella polyethylene wear and mismatched shapes in several knees. LEVEL OF EVIDENCE: III.

Oral Multimodal Analgesia for Total Joint Arthroplasty.

BACKGROUND: Oral multimodal analgesia for hip and knee arthroplasty is increasingly used as part of enhanced recovery protocols designed to minimize early postoperative pain and to facilitate early discharge, while minimizing undesirable side effects related to single-agent opioid administration. METHODS: This article is a review of previously published data evaluating the use of various oral medications in the management of postoperative pain after lower extremity arthroplasty and was presented as part of a symposium at the November 2016 AAHKS Annual Meeting. RESULTS: Multimodal analgesia has been shown to reduce opioid consumption and side effects, with a positive effect on both early and longer term outcomes for hip and knee arthroplasty patients. Medications directed at multiple points on the pain cascade minimize pain by different mechanisms. Suggested dosing regimens are proposed. CONCLUSION: Oral multimodal analgesia incorporating a combination of opioid and nonopioid analgesics, selective and nonselective anti-inflammatory drugs, acetaminophen, and gabapentinoids are recommended as a part of a pre-emptive approach to pain management in patients undergoing hip or knee arthroplasty. Reduction of opioid consumption and minimization of side effects are primary outcomes, and prevention of chronic pain can positively affect long-term results.

Is there an association between whole-body pain with osteoarthritis-related knee pain, pain catastrophizing, and mental health?

BACKGROUND: Greater levels of self-reported pain, pain catastrophizing, and depression have been shown to be associated with persistent pain and functional limitation after surgeries such as TKA. It would be useful for clinicians to be able to measure these factors efficiently. QUESTIONS/PURPOSES: We asked: (1) What is the association of whole-body pain with osteoarthritis (OA)-related knee pain, function, pain catastrophizing, and mental health? (2) What is the sensitivity and specificity for different cutoffs for body pain diagram region categories in relation to pain catastrophizing? METHODS: Patients (n = 267) with knee OA undergoing elective TKA at one academic center and two community orthopaedic centers were enrolled before surgery in a prospective cohort study. Questionnaires included the WOMAC Pain and Function Scales, Pain Catastrophizing Scale (PCS), Mental Health Inventory-5 (MHI-5), and a pain body diagram. The diagram documents pain in 19 anatomic areas. Based on the distribution of the anatomic areas, we established six different body regions. Our analyses excluded the index (surgically treated) knee. Linear regression was used to evaluate the association between the total number of nonindex painful sites on the whole-body pain diagram and measures of OA-related pain and function, mental health, and pain catastrophizing. Generalized linear regression was used to evaluate the association between the number of painful nonindex body regions (categorized as 0; 1-2; or 3-6) with our measures of interest. All models were adjusted for age, sex, and number of comorbid conditions. The cohort included 63% females and the mean age was 66 years (SD, 9 years). With removal of the index knee, the median pain diagram score was 2 (25(th), 75(th) percentiles, 1, 4) with a range of 0 to 15. The median number of painful body regions was 2 (25(th), 75(th) percentiles, 1, 3). RESULTS: After adjusting for age, sex, and number of comorbid conditions, we found modest associations between painful body region categories and mean scores for WOMAC physical function (r = 0.22, p < 0.001), WOMAC pain (r = 0.20, p = 0.001), MHI-5 (r = -0.31, p < 0.001), and PCS (r = 0.27, p < 0.001). A nonindex body pain region score greater than 0 had 100% (95% CI, 75%-100%) sensitivity for a pain catastrophizing score greater than 30 but a specificity of just 23% (95% CI, 18%-29%) . A score of 3 or greater had greater specificity (73%; 95% CI, 66%-79%) but lower sensitivity (53%; 95% CI, 27%-78%). CONCLUSIONS: We found modest associations between the number of painful sites on a whole-body pain diagram and the number of painful body regions and measures of OA-related pain, function, pain catastrophizing, and mental health. Patients with higher self-reported body pain region scores might benefit from further evaluation for depression and pain catastrophizing. LEVEL OF EVIDENCE: Level III, therapeutic study.

Consensus Statement on Indications and Contraindications for Medial Unicompartmental Knee Arthroplasty.

Previous work, now nearly 30 years dated, is frequently cited as the "gold standard" for the indications and contraindications for medial unicompartmental knee arthroplasty (UKA). The purpose of this article is to review current literature on the indications and contraindications to UKA and develop a consensus statement based on those data. Six surgeons with a combined experience of performing more than 8,000 partial knee arthroplasties were surveyed. Surgeons then participated in a discussion, emerging proposal, collaborative modification, and final consensus phase. The final consensus on primary indications and contraindications is presented. Notably, the authors provide consensus on previous contraindications, which are no longer considered to be contraindications. The authors provide an updated and concise review of the current indications and contraindications for medial UKA using scientifically based consensus-building methodology.

Use of tranexamic acid results in decreased blood loss and decreased transfusions in patients undergoing staged bilateral total knee arthroplasty.

BACKGROUND: Tranexamic acid (TXA) is an antifibrinolytic that reduces blood loss and transfusion rates in total joint arthroplasty. Blood loss and allogenic transfusion rates have not been well studied in patients receiving TXA and undergoing bilateral staged total knee arthroplasty (TKA). The purpose was to evaluate the effect of TXA on blood loss, hemoglobin (Hb) changes, and transfusion in patients undergoing staged bilateral TKA. STUDY DESIGN AND METHODS: The authors compared 51 patients undergoing staged bilateral TKA who received TXA (2 g; subjects) with 70 who did not (controls). There were no significant differences between the groups in terms of demographics or preoperative Hb. For each TKA, 1 g of TXA was administered intravenously 15 minutes before incision and 1 g was administered intravenously at tourniquet release. Blood loss, Hb levels, and transfusions were recorded. Statistical analyses were performed using computer software. Significance was set at 0.05. RESULTS: Subjects had a significantly lower (p < 0.001) mean (±SD) blood loss (373.8 ± 264.6 mL vs. 871.6 ± 457.7 mL), significantly higher (p < 0.005) Hb levels on Postoperative Days 1 and 2, and a significantly lower (p < 0.001) mean (±SD) number of transfused allogenic blood units (0.60 ± 0.84 units vs. 1.53 ± 1.30 units). CONCLUSIONS: TXA reduces blood loss, improves postoperative Hb, and decreases the allogenic blood transfusion requirements for patients undergoing bilateral staged TKA. TXA is an option for patients choosing bilateral staged TKA to decrease the risks associated with blood transfusion or when autologous blood is not available.

Stratification of standardized TKA complications and adverse events: a brief communication.

BACKGROUND: The Total Knee Arthroplasty (TKA) Complications Workgroup of the Knee Society developed a standardized list and definitions of complications associated with TKA. Twenty-two complications and adverse events believed important for reporting outcomes of TKA were identified. The Editorial Board of Clinical Orthopaedics and Related Research (®), the Executive Board of the Knee Society, and the members of the Knee Society TKA Complications Workgroup came to the conclusion that reporting of a list of TKA adverse events and complications would be more valuable if they were stratified using a validated classification system. QUESTIONS/PURPOSES: The purpose of this article was to stratify the previously published standardized list of TKA adverse events and complications. METHODS: A modified version of the Sink adaptation of the Clavien-Dindo Surgical Complication Classification was applied to the list of standardized TKA complications and adverse events. RESULTS: The proposed stratified classifications of TKA complications were reviewed and endorsed by the Knee Society. CONCLUSIONS: Stratification of TKA complications will allow more in-depth and detailed outcome reporting for surgeons, hospitals, third-party payers, government agencies, joint replacement registries, and orthopaedic researchers. This improvement in reporting of TKA complications will also improve the quality of orthopaedic literature.

A systematic review of clinical outcomes and survivorship after total knee arthroplasty with a contemporary modular knee system.

A systematic review appraising the clinical performance and safety of the primary SIGMA modular knee system (DePuy-Synthes, Warsaw, Ind.) found 5 registry reports and 53 journal publications reporting survivorship or postoperative increase in Knee Society scores on 241632 primary SIGMA knee arthroplasties. Pooled data from national joint registries and clinical studies on primary SIGMA knee survivorship were comparable. Both were higher than for all other knees in 5 national joint registries up to 5 years. Compared with pooled data from 2 independent systematic reviews of primary non-SIGMA knees, the SIGMA system provided comparable postoperative changes in Knee Society knee score and a nonsignificant trend of higher postoperative changes in Knee Society function score. This finding suggests that this knee system provides excellent durable results.

In-vivo alignment comparing patient specific instrumentation with both conventional and computer assisted surgery (CAS) instrumentation in total knee arthroplasty.

Patient specific instrumentation (PSI) was developed to increase total knee arthroplasty (TKA) accuracy and efficiency. The study purpose was to compare immediate post-operative mechanical alignment, achieved using PSI, with conventional and computer assisted surgery (CAS) instruments in high volume TKA practices. This prospective, multicenter, non-randomized study accrued 66 TKA patients using PSI. A computed tomography (CT) based algorithm was used to develop the surgical plan. Sixty-two percent were females, 99% were diagnosed with osteoarthritis, average age at surgery was 66 years, and 33 was the average body mass index. A historical control group was utilized that underwent TKA using conventional instruments (n=86) or CAS (n=81), by the same set of surgeons. Postoperative mechanical alignment was comparable across the groups. Operative time mean and variance were significant.

Four-Year Outcomes of Cementless Versus Cemented Fixation of a Newly Introduced Total Knee Arthroplasty Design.

BACKGROUND: Aseptic loosening continues to be a major cause of failure of total knee arthroplasty (TKA). Although cemented fixation remains the gold standard, there is renewed interest in cementless fixation as a means of decreasing this risk via biologic fixation. The purpose of this study was to evaluate the clinical outcomes of cemented and cementless versions of a newly introduced TKA design at an average of 4 years postoperatively. MATERIALS AND METHODS: This was a retrospective case-control study of 100 primary TKAs comparing cementless vs cemented TKAs using the same cruciate-retaining implant design (ATTUNE Knee System; DePuy Synthes). Fifty patients undergoing cementless TKA with a mean age of 60.8 years (range, 48-71 years) and body mass index (BMI) of 31.6 kg/m2 (range, 23.7-41.9 kg/m2) were matched to 50 patients undergoing primary cemented TKA with a mean age of 62.7 years (range, 51-73 years) and BMI of 30.1 kg/m2 (range, 24.6-43.9 kg/m2). The mean follow-up was 4.2 years (range, 4.0-4.4 years) in the cementless group and 7.6 years (range, 7.5-7.7 years) in the cemented group. Complications, clinical outcomes using the Knee Society Score (KSS), and radiographic analyses were evaluated at final follow-up. Student's t tests were used for statistical analyses. RESULTS: There was no statistical difference in age, BMI, and preoperative KSS between the two groups (P=.12, P=.15, and P=.55, respectively). There were no complications or reoperations in either cohort. There were no statistical differences in range of motion and total KSS at final follow-up between the two groups. Final total KSS had a mean of 91.1 for the cementless group and 93.7 for the cemented group. There was no radiographic evidence of component subsidence or loosening in either cohort. CONCLUSION: When compared with its cemented counterpart, the newly introduced cementless TKA design had similar excellent clinical improvements and radiologic results at an average of 4 years of follow-up. [Orthopedics. 2024;47(3):161-166.].

Robotic-assisted total knee arthroplasty reduces soft-tissue releases which improves functional outcomes: A retrospective study.

BACKGROUND: There is increasing use of Robotic-Assisted (RA) and personalized alignment techniques in total knee arthroplasty (TKA). The hypothesis of this study was that RA TKA would result in fewer soft-tissue releases, and that fewer soft-tissue releases would be associated with improved clinical outcomes. METHODS: A retrospective review of an internal company registry was conducted for all primary TKAs performed from Jan 1, 2014, through a database extract date of Nov 4, 2022. These were grouped by whether there was an intentional soft-tissue release performed (STR) during the surgery or not (NSTR) and whether RA was utilized. The incidence of STR was compared between RA-TKAs and those performed with manual instrumentation. Knee Society Score (KSS) and Knee Society Function Scores (KSFS) were collected at 6 months, 1 year and 2 years. Kaplan-Meier survivorship was performed. RESULTS: The incidence of STR was significantly lower for RA vs. Manual (43.81% Vs 86.62%, p < 0.0001). The TKAs with NSTR had higher KSFS compared to those with STR at 6 months (84.73 Vs. 77.51, p < 0.0001), 1 year (89.87 Vs. 83.54, p < 0.0001) and 2 years (90.09 Vs. 82.65, p < 0.0001). There was no difference in survivorship, or KSS at any time point. However, the NSTR group had improved KSS pain sub score at 2 years. CONCLUSION: The results of this observational, retrospective analysis found that the incidence of soft-tissue release was lower with RA-TKA. Further, regardless of if RA was used, avoiding releases was associated with improved KSFS and KSS pain scores through 2 years post-operatively.

Complications of total knee arthroplasty: standardized list and definitions of the Knee Society.

BACKGROUND: 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. QUESTIONS/PURPOSES: We developed a standardized list and definitions of complications and adverse events associated with TKA. METHODS: In 2009, The Knee Society appointed a TKA Complications Workgroup that surveyed the orthopaedic literature and proposed a list of TKA complications and adverse events with definitions. An expert opinion survey of members of The Knee Society was used to test the applicability and reasonableness of the proposed TKA complications. For each complication, members of The Knee Society were asked "Do you agree with the inclusion of this complication as among the minimum necessary for reporting outcomes of knee arthroplasty?" and "Do you agree with this definition?" RESULTS: One hundred two clinical members (100%) of The Knee Society responded to the survey. All proposed complications and definitions were endorsed by the members, and 678 suggestions were incorporated into the final work product. The 22 TKA complications and adverse events include bleeding, wound complication, thromboembolic disease, neural deficit, vascular injury, medial collateral ligament injury, instability, malalignment, stiffness, deep joint infection, fracture, extensor mechanism disruption, patellofemoral dislocation, tibiofemoral dislocation, bearing surface wear, osteolysis, implant loosening, implant fracture/tibial insert dissociation, reoperation, revision, readmission, and death. CONCLUSIONS: We identified 22 complications and adverse events that we believe are important for reporting outcomes of TKA. Acceptance and utilization of these standardized TKA complications may improve evaluation and reporting of TKA outcomes.

Why are total knee arthroplasties being revised?

Despite technical improvements, revision rates for total knee arthroplasties (TKAs) remain high. Our goal was to report the reason(s) for revision TKA in a large, current, multicenter series and compare those reasons with previously published reasons. We retrospectively identified 820 consecutive revision TKAs (693 patients, 2000-2012) from our 3 centers and recorded the primary reason for the revision. The top seven reasons for the revision were aseptic loosening (23.1%), infection (18.4%), polyethylene wear (18.1%), instability (17.7%), pain/stiffness (9.3%), osteolysis (4.5%), and malposition/malalignment (2.9%). Comparison with previously published reasons showed fewer TKA revisions for polyethylene wear, osteolysis, instability, and malalignment. These changes may represent improvements in surgical technique and implants.

Efficacy of multimodal perioperative analgesia protocol with periarticular medication injection in total knee arthroplasty: a randomized, double-blinded study.

Pain control is necessary for successful rehabilitation and outcome after total knee arthroplasty. Our goal was to compare the clinical efficacy of periarticular injections consisting of a long-acting local anesthetic (ropivacaine) and epinephrine with and without combinations of an α2-adrenergic agonist (clonidine) and/or a nonsteroidal anti-inflammatory agent (ketorolac). In a double-blinded controlled study, we randomized 160 patients undergoing total knee arthroplasty to receive 1 of 4 intraoperative periarticular injections: Group A, ropivacaine, epinephrine, ketorolac, and clonidine; Group B, ropivacaine, epinephrine, and ketorolac; Group C, ropivacaine, epinephrine, and clonidine; Group D (control), ropivacaine and epinephrine. Compared with Group D, Group A and B patients had significantly lower postoperative visual analog pain scores and nurse pain assessment and Group C patients had a significantly greater reduction in physical therapist pain assessment. We found no differences in other parameters analyzed.

Five- to ten-year outcomes for modular metal-on-metal total hip arthroplasty.

In recent years, metal-on-metal (MOM) arthroplasty has come under fire with reported adverse outcomes of metal hypersensitivity, adverse local tissue reaction (ALTR), and the carcinogenicity concern from systemic metal ions. We present a retrospective analysis of 354 primary total hip arthroplasties from 2 independent centers. Revision data, predicted survival and Harris Hip Scores (HHS) are reported. Nine hips (2.5%) underwent component revision, and 9 year predicted survival was 95.8%. One revision had elevated metal ions but no histological evidence of ALTR. Average HHS at a minimum 5 year follow up (range 5-10 years) improved significantly from 52 pre-operatively to 93 post-operatively. While a 2.5% revision rate and improved clinical outcomes are reported in this study, longer term follow-up is warranted to monitor for late complications.

Medial UKA: favorable mid-term results in middle-aged patients.

In middle-aged patients with knee arthritis, surgical treatment options include arthroscopic procedures, osteotomies, and unicompartmental and total knee arthroplasty. Unicompartmental knee osteoarthrosis is particularly challenging and controversial in such patients. From December 2001 through October 2005, we treated 32 consecutive middle-aged patients (46 to 59 years old) with 40 medial unicompartmental knee arthroplasties. Three patients were lost to follow-up, leaving 29 for our study. There were two reoperations: one for loosening at 3 years, and one for disease progression at 5 years. Implant survival was modeled using Kaplan-Meier survival function with observations censored if lost to follow-up. At the 6-year survivorship in this group, the overall implant survival rate was 94.1% (95% CI, 78.3-98.5). Knee Society scores had improved significantly (p < 0.001). There were no other instances of osteolysis or radiographic failure. We concluded that, at mid-term follow-up, unicompartmental knee arthroplasty provided satisfactory results for this challenging population.

All-polyethylene tibial components in obese patients are associated with low failure at midterm followup.

BACKGROUND: 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. QUESTIONS/PURPOSES: We therefore determined the (1) function, (2) occurrence of osteolysis, and (3) complications in a cohort of obese patients receiving all-polyethylene tibial components. PATIENTS AND METHODS: Between September 17, 1996, and December 19, 2002, we implanted all-polyethylene tibial components in 90 obese patients (125 knees); 24 patients (33 knees) died and 13 patients (17 knees) were lost to followup, leaving 53 patients (59%) with 75 knees. All surgeries were cruciate-retaining, tricompartmental TKAs. We evaluated patients with Knee Society Scores and serial radiographs. Minimum followup was 7 years (mean, 10.4 years; range, 7-14 years). RESULTS: At latest followup, mean Knee Society Score was 92 points. There were five tibial radiolucencies, all less than 1 mm and characterized as nonprogressive. We observed minimal, nonprogressive osteolysis in one knee. One patient required reoperation after a traumatic event. There were no implant-related failures and no implants at risk of failure. CONCLUSIONS: At an average 10-year followup, all-polyethylene tibial components were functioning well in this obese group. These findings confirm the effectiveness of all-polyethylene tibial components in obese patients.

Current and innovative pain management techniques in total knee arthroplasty.

Pain management is a major concern for patients contemplating total knee replacement surgery and is one of the leading causes of dissatisfaction after knee replacement. Substantial progress has been made over the past several years in improving pain control after total knee replacement using multimodal pain control, preemptive analgesia, and periarticular injections.