This was a multicenter, randomized, clinical trial to compare the 90-day 1) incidence of surgical site complications (SSC); 2) health care utilization (the number of dressing changes, readmission, and reoperation); and 3) the patient-reported outcomes (PRO) in high-risk patients undergoing revision total knee arthroplasty (rTKA) with postoperative closed incision negative pressure wound therapy (ciNPT) versus a standard of care (SOC) silver-impregnated occlusive dressing. A total of 294 rTKA patients (15 centers) at high-risk for wound complications were prospectively randomized to receive either SOC or ciNPT (n = 147 each). The ciNPT system was adjusted at 125 mmHg of suction. Investigated outcomes were assessed weekly up to 90 days after surgery. A preset interim analysis was conducted at 50% of the intended sample size, with planned discontinuation for clear efficacy/harm if a significance of Aim
Method
Two-stage revision arthroplasty for PJI may make use of an antibiotic-loaded cement spacer (ACS), as successful long- term prevention of reinfection have been reported using this technique.[i] However, there is little data on systemic complications of high-dose antibiotic spacers. Acute kidney injury (AKI) is of clinical significance, as the drugs most commonly utilized, vancomycin and aminoglycosides, can be nephrotoxic. We intended to determine the incidence of AKI in patients that underwent staged revision arthroplasty with an ACS, as well as to identify potential predisposing risk factors for the disease. Local databases of six different orthopaedic surgeons were retrospectively reviewed for insertion of either a static or articulating antibiotic cement spacer by from 2007–2017. Dose of antibiotic powder implanted, as well as IV antibiotic used, was collected from operative records. Demographics, comorbidities, and preoperative and postoperative creatinine and hemoglobin values were recorded from the EHR. AKI was defined by a more than 50% rise in serum creatinine from preoperative baseline to at least 1.4 mg/dL, as described by Menge et al.[ii] Variables were analyzed for the primary outcome of AKI within the same hospital stay as insertion of the ACS. Categorical variables were analyzed with Chi-Square test, and continuous variables with univariate logistic regression.INTRO
METHODS
High-dose antibiotic cement spacers are commonly used to treat prosthetic joint infections following knee arthroplasties. Several clinical studies have shown a high success rate with antibiotic cement spacers, however there is little data on the systemic complications of high-dose antibiotic spacers, particularly acute kidney injury (AKI). This study aims to determine the incidence of AKI and identify risk factors predisposing patients undergoing staged revision arthroplasty with antibiotic cement spacers. A single-institution, retrospective review was used to collect and analyze clinical and demographic data for patients who underwent staged revision total knee arthroplasty with placement of an antibiotic-impregnated cement spacer from 2006 to 2016. A search was made through specific procedure (DRG) and diagnostic (CD) codes. Baseline descriptive data were collected for all patients including age, sex, medical comorbidities, type and quantity of antibiotics used in the cement spacer, pre- and postoperative hemoglobin (Hg), BMI, smoking status, peak creatinine levels, and random vancomycin levels. Acute kidney injury was defined as a more than 50% rise in serum creatinine from a preoperative baseline within 90 days postoperatively.BACKGROUND
METHODS
Stiffness after total knee arthroplasty (TKA) has been reported to occur due to component malpositioning and/or oversizing, improper femoral component (FC) flexion and tibial component (TC) slope, tight extension gap, inaccurate joint line placement, deficient posterior osteophyte resection, heterotopic ossification (HO), poor patellofemoral joint reconstruction, poor posterior condylar offset restoration, and/or posterior cruciate ligament (PCL) under-resection or retraction. However, the importance of these potential factors for stiffness are not well documented in the medical literature. The aim of this study was therefore to evaluate specific radiographic parameters in patients who had stiffness after primary TKA. An IRB-approved retrospective chart review was performed to identify patients that were revised due to stiffness after TKA. We defined stiffness as 15º or more of flexion contraction, less than 75º of flexion or a range of motion (ROM) of 90º with the chief complaint of limited ROM and pain. Patients with history of previous revisions and/or ORIF, infection, or isolated polyethylene exchange were excluded. Patients with a minimum of 1 year radiographic follow-up were included. Radiographic measurements were performed as described by the Knee Society TKA Roentgenographic Evaluation System (KSRES). Two blinded observers performed all measurements. Descriptive data is reported as mean (range). Inter-observer correlations were reported using Intraclass correlations coefficient (ICC).Introduction
Material and Methods
A stiff total knee arthroplasty (TKA) is an uncommon but disabling problem because it causes pain and limited function. Revision surgery has been reported as a satisfactory treatment option for stiffness with modest benefits. The aim of this study was to evaluate the results of revision surgery for the treatment of stiffness after TKA. We defined stiffness as 15 degrees or more of flexion contracture or less than 75º of flexion or a range of motion of 90º or less presenting with a chief complain of limited range of motion and pain. We evaluated the results of forty-two revisions performed by one of four orthopedic surgeons due to stiffness after TKA. Patients with history of infection or isolated polyethylene insert exchange were excluded.Introduction
Methods
Symptomatic instability following total knee arthroplasty (TKA) is a leading cause of early failure. Despite numerous reports on instability, standardized diagnostic and treatment protocols for these patients continue to remain unclear. Most reports recommend component revision as the preferred treatment, because of poor outcomes and high failure rates associated with isolated tibial polyethylene insert exchange (ITPIE). However, modern implant systems and standardized protocols may potentially change this teaching. We performed an IRB-approved, retrospective review of 90 consecutive patients with minimum 2 years follow-up who underwent revision TKA for instability by one of four arthroplasty surgeons at a single institution. Mean age was 62.0 years (range, 41 to 83 years), and 73% of patients were women. Charts were reviewed for relevant preoperative clinical and physical exam findings, as well as pertinent intraoperative findings. Radiographs were analyzed for femoral and tibial component positioning. Pre- and post-operative Knee Society Scores (KSS) were calculated.Introduction
Methods
Smaller increments in the antero-posterior dimensions of femoral components allows significant improvements in balancing of the knee after TKA with restoration of more normal soft-tissue stability. The soft-tissue stability of the knee after TKA is often compromised by the fact that only a finite set of implantable component sizes is available to match bony anatomy. While this could be overcome with custom components, a more practical solution is a set of femoral components with smaller increments in the antero-posterior (AP) dimension. However, this results in a larger assortment of sizes of both implants and trial components. This study was performed to determine whether smaller increments in the AP sizing of knee prostheses would lead to real benefits in restoration of normal knee function and stability after TKA.Summary:
Introduction:
The purpose of this study was to determine the efficacy of a multi-modal blood conservation protocol that involved pre–operative autologous blood donations (2 units) in conjunction with erythropoietin supplementation as well as intra-operative conservation modalities. A retrospective chart review of 90 patients with simultaneous bilateral total knee arthroplasty done between 2006–2009 by one of the 3 senior authors was performed. Patients donated two units of blood 4 weeks prior to surgery and also received erythropoietin injections (40,000 units: 3 weeks, 2 weeks and 1 week prior to surgery). Intra- operative blood management included use of pneumatic tourniquet, re-infusion drains, local epinephrine injections and fibrin spray. Post-operatively, autologous transfusions were provided based on symptoms. Pre-donation blood levels, peri-operative hemoglobin and hematocrit levels along with transfusion records were assessed.Introduction
Methods
The new Knee Society Score has been developed and validated, in part, to characterize better the expectations, components of satisfaction, and the physical activities of the younger, more diverse modern population of TKA patients. This study aims to reveal patients' activity levels' post-TKA and to determine how it contributes to their subjective evaluation of the surgery. As part of a multi-centered and regionally diverse study sponsored by the Knee Society, the new Knee Society Score (KSS) was administered 243 patients (44% male; avg 66.4years; 56% female, avg 67.7years) following primary TKA (follow up > 1year, avg. 25mos). The new, validated KSS questionnaire consists of a traditional objective component, as well as subjective components inquiring into patient symptoms, satisfaction, expectations and activity levels as well as a survey of three physical activities that are viewed as important to the patients. Responses were analyzed as a whole group and as subgroups of male and female and as younger (<65) and older (>65).Introduction
Methods
Bone loss is a challenging reconstructive problem in revision total knee arthroplasty (TKA). Uncemented porous tantalum modular components are designed to act as substitutes for allograft bone in complex revision TKA with significant bone defects. A consecutive series of 23 revision TKAs performed by a single surgeon were reviewed at a minimum two-years following implantation. In all cases bone loss was assessed using the Anderson Orthopaedic Research Institute System, and porous tantalum components were used to augment the reconstructions when bone loss was encountered. Twenty-one patients had 23 procedures (2 bilateral) requiring the use of porous tantalum following 18 cases of aseptic loosening, 4 cases of staged re-implantation for infection, and 1 case of a periprosthetic patellar fracture and aseptic loosening. Structural bone graft was not used during this time period. Porous tantalum uses include: 20 distal and posterior femoral augments; 2 femoral cones; 8 patellar augments; and 18 tibial cones. 20 cases required augmentation in more than one area, and one case involved an extensor mechanism allograft. There were 2 cases of recurrent sepsis requiring removal of well-fixed tantalum components. At an average 37 months (24 to 73) no patients were lost to follow-up. Clinical follow-up in the remaining 21 cases showed reconstructions were functioning well with no revisions. Radiographic imaging showed re-establishment of the joint line, neutral mechanical axis, and signs of stable fixation of the augments. There were no cases of radiographic or clinical loosening at the most recent follow-up. Short term results with the use of porous tantalum augments and cones for bone loss in revision TKA demonstrate the versatile, and durable nature of these new reconstructive tools, at early follow-up.
Surgical instrumentation for total knee arthroplasty has improved the accuracy, reproducibility and reliability of the procedure. In recent years, minimally invasive surgery introduced instrumentation that was reduced in size to fit within the smaller operative field; with this move the impact and influence of technology became proportionately larger. The introduction of computer navigation is an attempt to improve the surgeon’s visibility in a limited operative field, improve the position of the resection guides, and ultimately the position of the final components. While it may be appealing to rely on computer navigation to perform a TKA, it is not artificial intelligence and does not make any of the surgical decisions. The procedure still is surgeon directed with navigation serving as a tool of confirmation with the potential for improvements in surgical accuracy and reproducibility. The accuracy of TKA has always been dependent upon the surgeon’s judgment, experience, ability to integrate images, utilize pre-operative radiographs, knowledge of anatomic landmarks, knowledge of knee kinematics, and hand eye co-ordination. Recent advances in medical imaging, computer vision and patient specific instrumentation have provided enabling technologies, which in a synergistic manner optimize the accurate performance of the surgery. The successful use of this technology requires that it not replace the surgeon, but support the surgeon with enhanced intra-operative feedback, integration of pre-operative and intra-operative information, and visual dexterity during the procedure. In developing smart tools or robotic systems, the technology must be: safe; accurate; compatible with the operative field in size and shape, as well be able to be sterilized; and must show measurable benefits such as reduced operative time, reduced surgical trauma and improved clinical outcomes. Advocates believe this is attainable and robotic assisted TKA can achieve levels of accuracy, precision and safety not accomplished by computer assisted surgery. Smart instruments and robotic surgery are helping us take the next step into the operating room of the future. The role of robots in the operating room has the potential to increase as technology improves and appropriate applications are defined. Joint replacement arthroplasty may benefit the most due to the need for high precision in placing instruments, aligning the limb and implanting components. In addition, this technology will reduce the number of instruments needed for the procedure potentially further improving efficiency in the operating room. As technology advances, robots may be commonplace in the surgical theater and potentially transform the way total knee arthroplasty is done in the future. Robotic surgery and smart tools are new innovative technologies and it will remain to be seen if history will look on its development as a profound improvement in surgical technique or a bump on the road to something more important.
John N. Insall accomplished unparalleled success as an orthopedic surgeon, implant designer, and teacher. Over a span of 4 decades he was a pioneer in the field of knee surgery and was instrumental in evolving total knee arthroplasty to its current state of excellence. His legacy in total knee implant design began with the Duocondylar and Duopatellar prosthesis; was revolutionary with the implantation of the first Total Condylar Prosthesis -the first modern prosthesis; followed by posterior cruciate ligament substitution with the Insall – Burstein Posterior Stabilized Prosthesis; and ultimately with the Legacy Posterior Stabilized High Flexion Prosthesis – a fixed and mobile bearing high performance implant. Recognizing the importance of surgical technique with any implant design, Insall simultaneously described the surgical technique of ligament releases for restoring axial alignment and balancing the flexion and extension gaps. Over time his innovations have been embraced by the majority of surgeons and have become the foundation of what we do today. During more than 40 years of clinical practice, John N. Insall was an unselfish educator. He shared his clinical experiences with the medical community by publishing, along with his students and associates, an exhaustive array of articles and books on various afflictions of the knee. Recognized by his contemporaries as a leader in the field of total knee arthroplasty, he was elected president of the Knee Society in 1987. For the entire orthopedic community he continued to work laboriously, sharing his experiences with his fellows and colleagues until his death in 2000. The life of John N. Insall will be remembered in perpetuity for his unparalleled influence on knee surgery.
The influence of Posterior Cruciate Ligament (PCL) removal and re-establishment of the posterior condylar recess on flexion and extension gaps width during posterior-stabilized Total Knee Arthroplasty (TKA) is still controversial. It has been reported that PCL resection lead to a selective increase of the flexion space of 3–4 mm, creating a potential for instability in flexion. Our hypothesis was that these surgical steps will equally increase both gaps. Measurements of the flexion and extension gaps heights were obtained during different surgical phases in 50 consecutive primary posterior-stabilised TKAs using a tensor device and a calibrated torque wrench. There was a slight symmetrical increase in both gaps after PCL release. In extension the width of the gap increased on average 1.3 mm and 1.0 mm in the medial and lateral compartment respectively. The same pattern was observed in flexion, averaging 1.3 mm medially and 1.3 mm laterally. Another increase of the two gaps was observed after the posterior condylar osteophytes were removed and the posterior recess was re-established. The gaps in extension increased, with respect to the baseline value, on average 1.8 mm medially and 1.8 mm laterally, while in flexion the increase averaged 2.0 mm and 2.2 respectively on the medial and lateral side. Again there were no statistical differences between flexion and extension gaps. No independent differences between the flexion and extension gaps were found in any considered surgical phase. PCL removal and re-establishment of posterior condylar recess does not seem to require any additional consideration in gap balancing during posterior-stabilized TKA.
The survivorship method of analysis has been used to compare the failure rate and overall success of 1,430 cemented primary total knee arthroplasties performed at The Hospital for Special Surgery over a 15-year period. There were 224 total condylar prostheses with a polyethylene tibia, 289 of the posterior stabilised type with an all polyethylene tibia, and 917 posterior stabilised with a metal-backed tibial component. There were 12 failures in the total condylar series, giving an average annual failure rate of 0.65% and a 15-year success rate of 90.56%. The posterior stabilised prosthesis with a polyethylene tibia showed an average annual failure rate of 0.27% and a 10-year success rate of 97.34%, and this prosthesis with a metal-backed tibial component gave an annual failure rate of 0.19% and a seven-year success rate of 98.75%. The overall survival rate was not influenced by sex or age, diagnosis or the percentage of ideal body weight. No metal-backed tibial components have yet needed revision for loosening. It seems that infection will be the major cause of failure.
