Excursion of Oscillating Saw Blades in Total Knee Arthroplasty

Intraoperative disruption of the medial collateral ligament during total knee arthroplasty is an uncommon complication that can be avoided by retractor placement as well as by careful cutting of the femur and tibia. This study evaluated the excursion of a small and large oscillating saw blade and compared the data against the widths of both the medial and lateral femoral condyle cuts. We discovered that the large saw blade had a statistically significantly larger excursion than the medial and lateral condyle width in women, as well as the lateral condyle width in men. The small saw blade excursion did not exceed any condyle width. We conclude that the smaller saw blade should be considered when making these cuts because the excursion of the large saw blade may exceed the width of cut needed and endanger important structures such as collateral ligaments.     

Demonstration of Saw Blade Accuracy and Excursion : A Cadaveric Comparison Study of Blade Types Used in Total Knee Arthroplasty

In total knee arthroplasty, outcomes partly depend on accurate osteotomies and integrity of stabilizing structures. We compared accuracy and excursion between a conventional and an oscillating tip saw blade. Two sets of osteotomies were made on cadaveric knees. Bi-planar accuracy was compared using computer navigation, and excursion was compared using methylene blue. Wilcoxon-Mann–Whitney testing demonstrated no significant difference in blade accuracy (p = 0.35). Blades were within 0.5 degrees of neutral coronally and 2.0 degrees sagittally. The oscillating tip blade demonstrated less dye markings on the surrounding tissues. Accurate osteotomies and soft tissue protection are critical to successful arthroplasties. Although comparative accuracy was equal, the oscillating tip blade exhibited less excursion displaying potential for less iatrogenic soft tissue injuries leading to catastrophic failure.     

Intraoperative Practice Variability in Total Knee Arthroplasty

BackgroundConsiderable practice variability exists among orthopedic surgeons performing total knee arthroplasty (TKA). The purpose of this study is to understand what TKA surgical and perioperative techniques are standard among high-volume academic knee arthroplasty surgeons.MethodsA written survey with 59 questions regarding management preferences in TKA was distributed by the 2018 John N. Insall Traveling Fellows to all arthroplasty-trained attending physicians at 13 medical centers, with 45 responses recorded.ResultsSurveyed surgeons performed unicompartmental knee arthroplasty (88%) and bilateral TKA (87%). Most surveyed surgeons rarely or never performed outpatient primary TKA (71%). Conventional alignment guides and cemented implants were used by 80% of respondents. Most surgeons used posterior-stabilized implants (67%), followed by cruciate-retaining (20%), ultracongruent (20%), and medial congruent or medial pivot designs (17.8%). Surveyed surgeons frequently or always resurfaced the patella (73%), used a tourniquet for the entire case (73%), and used tranexamic acid for all TKAs (91%). The most common locations for intra-articular anesthetic injection were the arthrotomy (91%), the periosteum (84%), and the medial posterior capsule (82%). Saline (62%) and dilute iodine (47%) were the most common irrigation fluids. The arthrotomy was most commonly closed with running barbed suture (60%) followed by interrupted vicryl (40%). Skin closure was predominantly with running monocryl (60%) followed by staples (29%). Anticoagulation for TKA was primarily aspirin 81 mg BID (60%).ConclusionThere was considerable variability among surgeons polled although a strong preference for more conventional and less developmental techniques prevailed.     

Popliteal Artery Injury Associated With Total Knee Arthroplasty: Trends,Costs and Risk Factors

Popliteal artery injury is a relatively rare but potentially devastating complication of total knee arthroplasty (TKA). We analyzed the Nationwide Inpatient Sample from 1998 to 2009 to determine the actual incidence, risk factors and consequences of this complication. There were 1,120,508 hospitalizations coded for TKA; of these, 633 (0.057%) were identified as having a popliteal artery injury. The rate of injury remained relatively constant though the number of both TKAs and injuries have risen annually by 0.65% and 0.5%, respectively. Significant risk factors included revision surgery, peripheral vascular disease, weight loss, renal failure, coagulopathy, and metastatic cancer. Consequences were increased hospital charges, length of stay, and mortality rates. Because the rate of popliteal artery injury is not diminishing with time and morbidity and mortality are high, patients should be assessed for known risk factors for popliteal artery injury.     

人工全膝关节置换术的临床应用

目的：探讨人工全膝关节置换在临床应用的疗效。方法：1999年5月～2003年4月共有28例患者02膝）在我院行人工全膝关节置换术,其中男性10例,女性18例,年龄最大72岁,最小32岁（平均56．7岁）,晚期骨性关节炎16膝,类风湿性关节炎12膝,骨肿瘤2膝,创伤性关节炎2膝。术前膝关节平均活动度为52度,HSS评分平均为41分。术后平均随访时间为1年4个月。结果：28例32膝中有1例术后发生浅表感染,经换药后好转。其余患者疗效满意,膝关节平均活动度改善为85度,HSS评分平均为79．5分。结论：对于严重的骨性关节炎、类风湿性关节炎晚期、创伤性关节炎、膝部肿瘤等保守治疗无效的疾病人工全膝关节置换是一种较好的选择,但应严格掌握手术适应证和熟练的手术操作技巧才能取得满意的疗效。     

Ten-Year Follow-Up of High-Flexion Versus Conventional Total Knee Arthroplasty: A Matched-Control Study

BackgroundHigh-flexion total knee arthroplasty (HF-TKA) prostheses were designed with hopes of improving knee function. Studies have suggested increased failure with HF-TKAs. The purpose is to compare clinical results of HF-TKA versus conventional TKA (C-TKA) from the same implant system with long-term follow-up.MethodsThis review of prostheses implanted between 2004 and 2007 matched 145 of 179 possible HF-TKAs with 145 of 1347 possible C-TKAs. Mean follow-up was 121.5 ± 20.3 months. We were unable to match 12 HF-TKAs. HF-TKAs with less than 8-year follow-up were excluded. The primary outcome was failure requiring revision. Secondary outcomes included range of motion (ROM), Knee Society Scores (KSS), and radiolucent lines.ResultsIn the matched cohort, there were 15 HF-TKA reoperations, 8 of which involved component revisions. There were 12 reoperations in the C-TKA cohort but no component revisions (P = .001). The analysis of the unmatched cohorts revealed a higher revision rate for HF-TKAs (P = .039) (HF-TKA: 10/179 vs C-TKA: 27/1347). At final follow-up, HF-TKAs exhibited more prosthesis radiolucent lines without evidence of loosening. Particularly, HF-TKAs demonstrated more femoral zone IV radiolucencies (38.7%) at final follow-up compared with C-TKAs (13.8%) (P < .001). There were no differences found between cohorts in ROM or KSS.ConclusionThis study found an increased incidence of failure requiring revision with the HF-TKA in the matched and unmatched analyses. Higher incidences of radiolucent lines were found with HF-TKA. With no observed differences in ROM or KSS and a higher rate of failure with HF-TKA, there appears to be no advantage for use of the HF-TKA.     

Incidence of Leg-Length Discrepancy After Index Hinge Total Knee Arthroplasty

BackgroundLeg-length discrepancies are not commonly associated with total knee arthroplasty (TKA); however, hinge TKA is a complex form of knee reconstruction where functionality of all knee ligaments is replaced by the TKA construct. The purpose of this study is to evaluate the incidence of leg-length discrepancies after unilateral index hinge TKA and association with patient outcomes.MethodsA retrospective review was performed of all patients who underwent unilateral index hinge TKA at a single academic institution from 1999 to 2019. Among 671 patients who underwent index hinge TKA, 188 (28%) had full-length standing anteroposterior hip-to-ankle radiographs available for review both preoperatively and postoperatively. All patients with a leg-length change ≥2 cm were also contacted with a standardized questionnaire to assess for complications. The mean age was 65 years, the mean body mass index was 33 kg/m², and 52% were female. The mean number of prior surgeries was 2 (range, 0-12).ResultsThe absolute mean and median change in leg lengths was 20 mm and 13 mm, respectively (range, 0-130 mm). Lengthening occurred in 119 (63%) patients compared with shortening in 69 (37%) patients. An absolute change in leg lengths ≥1 cm was observed in 109 (58%) patients, ≥2 cm in 63 (34%) patients, and ≥5 cm in 15 (8%) patients.ConclusionLarge changes in the leg length are common after hinge TKA, likely secondary to altered soft-tissue constraints. Surgeons should be cognizant of potential changes in the leg length in the setting of hinge TKA and incorporate this into preoperative planning and patient counseling.Level of EvidenceLevel IV, therapeutic.     

使用与不用骨水泥固定人工膝关节置换术后疗效的比较

探讨使用与不用骨水泥固定氧化铝陶瓷制NCU型TKA术后的疗效。1989～1995年,为了治疗晚期骨性关节病及类风湿病,共施行NCU型TKA68例103个关节。对获得平均随访5年8个月的65例99个关节的以胫骨假体为中心的临床评价及X线计测的结果进行了比较性分析。临床评价方法是以JOA膝关节评价基准为标准,X线的评价方法是将术前、术后、最终调查时的正侧位X线照片数字化后输入电子计算机利用电脑软件系统进行了计测与评价。65例99个关节TKA术后经随访5年以上的结果表明NCU型TKA术后获得了比较良好的疗效。术后并发症7％,再手术率5％,不用骨水泥组疗效劣于使用骨水泥固定组,两组间的疼痛评分及透亮线出现率的差异均有显著性统计学意义。     

Popliteal Pseudoaneurysm After Total Knee Arthroplasty Secondary to Intraoperative Arterial Injury With a Surgical Pin : Review of the Literature

Pseudoaneurysms of the popliteal artery after total knee arthroplasty are rare. Although many possible explanations are proposed in the literature, no intimate mechanism of injury to the artery is previously described. We report on a case of popliteal pseudoaneurysm after a total knee arthroplasty that presented clinically on the second postoperative day. Open vascular surgery with resection of the pseudoaneurysm and end-to-end bypass of contralateral saphena vein graft was successfully performed. At the time of the surgery, a hole was clearly identified on the anterior wall of the popliteal artery due to a perforation with a pin used during the knee arthroplasty. The patient had no further complications.     

Twelve-Year Follow-Up of Navigated Computer-Assisted Versus Conventional Total Knee Arthroplasty: A Prospective Randomized Comparative Trial

Background

Navigated computer-assisted total knee arthroplasty (TKA) was introduced to expedite long-term survival based on improved postoperative implantation accuracy. However, long-term outcome data after 10 years or more are rare, even available meta-analyses show controversial study results.

Changes in the Medial and Lateral Posterior Condylar Offset in Total Knee Arthroplasty

The purpose of this study was to clarify the changes between preoperation and postoperation in each posterior condylar offset (PCO) using computed tomography (CT) and to compare them to conventional radiographic (x-ray) evaluation in total knee arthroplasty. One hundred nine knees in 97 patients were evaluated. The medial PCO was significantly larger before surgery. The lateral PCO was significantly larger after surgery. Changes in the PCO on x-ray showed no significant correlation with the changes observed in the CT-evaluated medial (R = 0.028) and lateral PCO (R = 0.190). Changes in PCO observed by x-ray did not reflect those of the medial or lateral condyles on CT. We recommend CT-based evaluation of PCO by condyle when assessing the influence of PCO on range of motion following total knee arthroplasty.     

Isokinetic Strength Testing of Minimally Invasive Total Knee Arthroplasty Recovery

Fifty patients underwent isokinetic muscle strength testing before surgery and at 6 weeks, 3 months, 6 months, and 1 year after unilateral total knee arthroplasty using the minisubvastus surgical technique. Quadriceps muscle strength returned to preoperative levels by 3 months postoperatively and was 17% stronger at 6 months and 30% stronger at 1 year than preoperative levels (P < .05). At 1 year, the quadriceps strength of the involved knee was equivalent to that of the uninvolved knee (P = .81). When the entire study population was subdivided by age, weight, sex, and the presence of arthritis in the uninvolved knee, each subgroup still had equivalent quadriceps strength between the involved and uninvolved knees. This prospective study demonstrated that the minisubvastus total knee arthroplasty technique led to a more rapid and more complete recovery of muscle strength than has been previously demonstrated after total knee arthroplasty with a medial parapatellar arthrotomy.     

Variation of Medicare Payments for Total Knee Arthroplasty

We analyzed the 2009 Medicare inpatient claims data and other databases to estimate Medicare payments for primary or revision total knee arthroplasty (TKA). The average Medicare hospital payment per procedure was $13,464 for primary TKA (n = 227,587) and $17,331 for revision TKA (n = 18,677). For both primary and revision TKAs Medicare payments varied substantially across patients, hospitals and healthcare markets. Less than one percent of primary TKA cases but seven percent of revision TKA cases triggered Medicare “outlier” payments, which were $10,000 or higher per case beyond regular diagnosis-related-group payments. Urban and major teaching hospitals were more likely to treat these unusually expensive cases. Hospitals in the Northeast and West regions tended to receive higher Medicare payments than hospitals in the Midwest.     

Socioeconomic Disparities in the Utilization of Total Knee Arthroplasty

BackgroundDespite strong evidence supporting the efficacy of total knee arthroplasty (TKA), studies have shown significant socioeconomic disparities regarding who ultimately undergoes TKA. The purpose of the current study is to evaluate socioeconomic factors affecting whether a patient undergoes TKA after a diagnosis of osteoarthritis.MethodsFrom 2011 to 2018, claims for adult patients diagnosed with knee osteoarthritis in the New York Statewide Planning and Research Cooperative System (SPARCS) database were analyzed. International Classification of Diseases (ICD), 9/10 CM codes were used to identify the initial diagnosis for each patient. ICD 9/10 PCS codes were used to identify subsequent TKA. Logistic regression analysis was performed to determine the effect of patient factors on the likelihood of having TKA.ResultsOf 313,794 osteoarthritis diagnoses, 33.3% proceeded to undergo TKA. Increased age (OR 1.007, P < .0001) and workers’ compensation relative to commercial insurance (OR 1.865, P < .0001) had increased odds of TKA. Compared to White race, Asian (OR 0.705, P < .0001), Black (OR 0.497, P < .0001), and “other” race (OR 0.563, P < .0001) had lower odds of TKA. Hispanic ethnicity (OR 0.597, P < .0001) had lower odds of surgery. Compared to commercial insurance, Medicare (OR 0.876, P < .0001), Medicaid (OR 0.452, P < .0001), self-pay (OR 0.523, P < .0001), and “other” insurance (OR 0.819, P < .0001) had lower odds of TKA. Increased social deprivation (OR 0.987, P < .0001) had lower odds of TKA.ConclusionTKA is associated with disparities among race, ethnicity, primary insurance, and social deprivation. Additional research is necessary to identify the cause of these disparities to improve equity in orthopedic care.     

The Impact of Changing Total Knee Arthroplasty Implants at a High-Volume Institution

BackgroundThe ability of a group of high-volume arthroplasty surgeons to simultaneously change their preferred primary total knee arthroplasty (TKA) implant of choice to another, has not been explored in the literature to date. The main hypothesis was that such a change could be made with no significant impact on clinical outcomes.MethodsThis is a retrospective cohort study comparing the last 500 consecutive TKAs implanted of a routinely used TKA implant (NexGen; Zimmer, Warsaw, IN) with the first 500 consecutive TKAs implanted of a newly adopted TKA implant (Triathlon; Stryker, Mahwah, NJ) at an institutional level. Primary outcomes of importance included all complications that occurred either intraoperatively or early postoperatively, early all-cause revision rate, and early reintervention rate.ResultsThere was a 1.2% (n = 6) complication rate in the NexGen cohort compared to 0.8% (n = 4) in the newly adopted Triathlon cohort (P = .75). The rate of intraoperative fracture was 1% in the NexGen cohort and 0.6% in the Triathlon cohort (P = .72). The early all-cause revision rate for the NexGen TKA was 1% (n = 5) compared to 0.8% (n = 4) in the Triathlon cohort (P = 1.0). The manipulation under anesthesia (MUA) rate in the NexGen cohort was 2.4% compared to 4.6% in the Triathlon cohort (P = .058). The only predictor variable associated with MUA rate was American Society of Anesthesiologists grade, where there was a significantly lower rate of MUA with a higher American Society of Anesthesiologists grade (P = .042).ConclusionIt is possible to implement the institution-wide adoption of an established, high-performing TKA implant without any negative implications in relation to early revision rates, perioperative complication rates, and reintervention rates. This study is the first of its kind to be reported in the literature.     

Lysis of Adhesion for Arthrofibrosis After Total Knee Arthroplasty Is Associated With Increased Risk of Subsequent Revision Total Knee Arthroplasty

BackgroundThe aim of this study is to determine incidence of lysis of adhesion (LOA) for postoperative arthrofibrosis following primary total knee arthroplasty (TKA), patient factors associated with LOA, and impact of LOA on revision TKA.MethodsPatients who underwent primary TKA were identified in the Humana and Medicare databases. Patients who underwent LOA within 1 year after TKA were defined as the “LOA” cohort. Multiple binomial logistic regression analyses were performed to identify patient factors associated with undergoing LOA within 1 year after index TKA, and identify risk factors including LOA on risk for revision TKA within 2 years of index TKA.ResultsIn total, 58,538 and 48,336 patients underwent primary TKA in the Medicare and Humana databases, respectively. Incidence of LOA within 1 year after TKA was 0.56% in both databases. Age <75 years was a significant predictor of LOA in both databases (P < .05 for both). Incidence of revision TKA was significantly higher for the “LOA” cohort when compared to the “TKA Only” cohort in both databases (P < .0001 for both). LOA was the strongest predictor of revision TKA within 2 years after index TKA in both databases (P < .0001 for both). Additionally, age <65 years, male gender, obesity, fibromyalgia, smoking, alcohol abuse, and history of anxiety or depression were independently associated with increased odds of revision TKA within 2 years after index TKA (P < .05 for all).ConclusionIncidence of LOA after primary TKA is low, with younger age being the strongest predictor for requiring LOA. Patients who undergo LOA for arthrofibrosis within 1 year after primary TKA have a substantially high risk for subsequent early revision TKA.Level of EvidenceIII, Retrospective Cohort Study.     

Spinal Versus General Anesthesia in Total Knee Arthroplasty: Are There Differences in Complication and Readmission Rates?

BackgroundSpinal anesthesia (SP) utilization continues to expand in total knee arthroplasty (TKA). However, little is known regarding differences in complication rates between spinal and general anesthesia used for primary TKA. Therefore, the purpose of this study is to compare the length of stay (LOS), operative time, and readmission and revision rates between patients who received spinal and general anesthesia during TKA.MethodsThe American Joint Replacement Registry (AJRR) was used to identify primary elective TKA patients from 2017 to 2020. Patients were divided into 2 cohorts, general (GN) and SP, based on the mode of anesthesia administered during the index surgery. In total, 270,251 TKAs were identified, of which 126,970 (47.0%) received general anesthesia and 143,281 (53.0%) received spinal anesthesia. Length of stay, operative time, 90-day readmission, and 90-day revisions were compared between the 2 groups. Multivariable logistic regression analyses were used to adjust for potential confounders.ResultsAfter accounting for confounding factors, SP was associated with a lower risk of having a LOS greater than 3 days (odds ratio [OR] 0.470, 95% confidence interval [CI] 0.454-0.487, P < .0001), but a slightly higher likelihood of having a longer operative time (OR 1.075, 95% CI 1.056-1.094, P < .0001). SP was also linked to lower rates of 90-day readmission (OR 0.845, 95% CI 0.790-0.904, P < .0001) and lower risk of 90-day all-cause revision (OR 0.506, 95% CI 0.462-0.555, P < .0001).ConclusionSP was associated with a lower 90-day readmission rate and a lower risk of 90-day revision. These findings support the best practice guidelines of The Joint Commission to use spinal anesthesia when possible as part of an enhanced recovery after surgery (ERAS) pathway.     

Arterial Injury in Total Knee Arthroplasty

Arterial complications associated with knee arthroplasty are relatively rare, although probably underreported, complications of knee arthroplasty that carry a risk of significant morbidity. Thorough preoperative assessment and close liaison with a vascular surgeon, combined with an appreciation of common anatomical variants or distorted anatomy, may help prevent both thromboembolic and direct injuries from occurring. Clinical features of arterial complications following knee arthroplasty may vary significantly from acute hemorrhage or ischemia in the immediate postoperative period to chronic pain and swelling presenting even months following the procedure. There is potential for diagnostic confusion and delay that may adversely affect outcome. Early diagnosis along with vascular surgical review and intervention is key to successful management.