Aims

The use of cementless total knee arthroplasty (TKA) components has increased during the past decade. The initial design of cementless metal-backed patellar components had shown high failure rates due to many factors. The aim of this study was to evaluate the clinical results of a second-generation cementless, metal-backed patellar component of a modern design.

During total knee arthroplasty (TKA), a tourniquet is often used intraoperatively. There are proposed benefits of tourniquet use including shorter duration of surgery, improved surgical field visualization and increased cement penetration which may improve implant longevity. However, there are also cited side effects that include increased post-operative pain, slowed recovery, skin bruising, neurovascular injury and quadriceps weakness. Randomized controlled trials have demonstrated no differences in implant longevity, however they are limited by short follow-up and small sample sizes. The objective of the current study was to evaluate the rates of revision surgery among patients undergoing cemented TKA with or without an intraoperative tourniquet and to understand the causes and risk factors for failure.

A retrospective cohort study was undertaken of all patients who received a primary, cemented TKA at a high-volume arthroplasty centre from January 1999 to December 2010. Patients who underwent surgery without the use of a tourniquet and those who had a tourniquet inflated for the entirety of the case were included. The causes and timing of revision surgery were recorded and cross referenced with the Canadian Institute of Health Information Discharge Abstract Database to reduce the loss to follow-up. Survivorship analysis was performed with the use of Kaplan-Meier curves to determine overall survival rates at final follow-up. A Cox proportional hazards model was utilized to evaluate independent predictors of revision surgery.

Data from 3939 cases of primary cemented TKA were available for analysis. There were 2276 (58%) cases in which a tourniquet was used for the duration of the surgery and 1663 (42%) cases in which a tourniquet was not utilized. Mean time from the primary TKA was 14.7 years (range 0 days - 22.8 years) when censored by death or revision surgery. There were 150 recorded revisions in the entire cohort, with periprosthetic joint infection (n=50) and aseptic loosening (n=41) being the most common causes for revision. The cumulative survival at final follow-up for the tourniquetless group was 93.8% at final follow-up while the cumulative survival at final follow-up for the tourniquet group was 96.9% at final follow-up. Tourniquetless surgery was an independent predictor for all-cause revision with an HR of 1.53 (95% CI 1.1, 2.1, p=0.011). Younger age and male sex were also independent factors for all cause revision.

The results of the current study demonstrate higher all-cause revision rates with tourniquetless surgery in a large cohort of patients undergoing primary cemented TKA. The available literature consists of short-term trials and registry data, which have inherent limitations. Potential causes for increased revision rates in the tourniquetless group include reduced cement penetration, increased intraoperative blood loss and longer surgical. The results of the current study should be taken into consideration, alongside the known risks and benefits of tourniquet use, when considering intraoperative tourniquet use in cemented TKA.

Aims

The aim of this study was to compare the clinical outcomes of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) during the first six weeks and at one year postoperatively.

Aims

The aim of this study was to compare robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) in order to determine the changes in the anatomy of the knee and alignment of the lower limb following surgery.

Introduction

Recent total knee arthroplasty (TKA) designs have featured more anatomic morphologies and shorter tibial keels. However, several reports have raised concerns regarding the impact of these modifications on implant longevity. This study's purpose is to report the early performance of a modern, cemented TKA design.

Background

Secondary osteonecrosis of the knee (SOK) generally occurs in relatively young patients in their working years; at advanced stages of SOK, the only viable surgical option is total knee arthroplasty (TKA). We conducted a retrospective study to investigate implant survivorship, clinical and radiographic outcomes, and complications of cemented TKA with/without patellar resurfacing for SOK.

Aims

The aim of this study was to compare the actual cost of a cemented and cementless total knee arthroplasty (TKA) procedure.

There is no question that at some point many TKAs will be cementless-the question is when. The advantages of cementless TKA include a shorter operative time, no need for a tourniquet, more suitability for MIS, no concern for cement extrusion, and the history of THA. The concerns for cementless TKA include the history to date with cementless TKA (tibia and metal-backed patella), variable bony substrate, surgical cut precision, cost, revision concerns, and the patella (for patella component resurfacers). Cemented total knee arthroplasty remains the gold standard and has proven to provide durable results in most patients. The early experience with cementless tibial fixation was problematic due to tibial micromotion leading to pain and loosening. Screw fixed tibial components had additional problems as portals for polyethylene debris leading to tibial osteolysis. Moreover, metal-backed patellar components were associated with a high failure rate and most surgeons began to cement all three components. Renewed interest in cementless tibial fixation is driven in part by newer materials felt to be more suitable for ingrowth and by the perceived benefit of minimally invasive surgery. One of the concerns in limited exposure total knee arthroplasty is the difficulty in preventing the extravasation of cement posteriorly. If there is evidence-based data that quad sparing non-patella everting and limited incision length facilitates rehabilitation and does not jeopardise outcome, cementless tibial fixation will be a more attractive option in some patients. An additional concern is that the tibial surface is frequently quite variable in terms of the strength of the cancellous bone. Bone cement stabilises those differences and provides a homogeneous platform for load bearing through the tibial component

Introduction. Cemented total knee arthroplasty (TKA) remains the gold standard with survivorship above 90% at greater than 10 years postoperatively. However, with younger, heavier, more active patients undergoing TKA at an increasing rate, cementless implants have the appeal of potential for improved implant fixation longevity and decreased rates of aseptic loosening. The cementless implants are more expensive than their cemented counterparts such that implant costs may create a barrier to utilization. However, such comparisons fail to consider the unavoidable additional costs of cementing, including the cost of operating room time, cement and cementing accessories. The purpose of this study is to compare the actual cost of cemented and cementless TKA. Methods. The TKA cost calculation included the cost of operative time, implants, cement and cementing accessories. The difference in operative time between cemented and cementless TKA was determined from a previously published study of 100 TKAs performed using a cemented (55) or press fit (45) implant of the same design performed at a single institution by four fellowship trained arthroplasty surgeons. The decision to use cemented or cementless design in these patients was made based on patient bone quality intraoperatively. Operative time was compared between groups using a Student's two-tailed T-test. The cost of operating room time was based on estimates in the recent literature. The cost of cement and cementing accessories was estimated based on publically available market data. The cost of implants was estimated from institutional data for multiple companies. Results. The cost comparison between cemented and cementless total knee arthroplasty is summarized in Table 1. Mean operative time for cemented TKA was 14.3 minutes longer than for cementless TKA (94.7 + 15.2 vs. 80.4 + 15.7, p<0.01). The estimated cost of one minute of operating room time in the literature ranges from $30 to $60. For our analysis, we used an estimate of $36 per minute obtained from a recently published multi-center study. This resulted in an average operating room time cost $3406 for cemented and $2894 for cementless TKA. Antibiotic cement costs an average of $250 per bag and antibiotic-free cement costs an average of $75 per bag. Cement mixing techniques vary across surgeons. Approximately 95% use a vacuum system and 5% use a mixing bowl. The cost of vacuum systems ranges from $80 for an enclosed bowl to $125 for a vacuum system that can be directly connected to a cement gun. The cost of a plastic mixing bowl and spatula is $20. The cost of the disposables from a cement injection kit is $25. The average cost of a primary TKA implant, including femoral, tibial and polyethylene liner components, is $3530 for cemented and $4659 for cementless designs. Patellar resurfacing is not routinely used at our institution and therefore was not included in implant cost. Based on our calculations, the average cost of a cementless TKA is $7553. Using the cheapest cementing technique with 2 bags of plain cement and a manual mixing bowl with spatula, the cost of a cemented TKA $7114. Using the most expensive cementing technique with 2 bags of antibiotic cement and a cement gun compatible vacuum mixer, the cost of a cemented TKA is $7564. Conclusion. Cemented TKA remains the gold standard and still accounts for most procedures. Cementless TKA is increasing in utilization and may decrease the rate of aseptic loosening, especially in the rapidly growing young, active population undergoing TKA. Although cementless implants remain more expensive than cemented implants at most institutions, the actual overall cost of the two procedures is similar if operative time, cement and cementing accessories are considered. For any figures or tables, please contact authors directly

As the number of younger and more active patients treated with total knee arthroplasty (TKA) continues to increase, consideration of better fixation as a means of improving implant longevity is required. Cemented TKA remains the reference standard with the largest body of evidence and the longest follow-up to support its use. However, cementless TKA, may offer the opportunity of a more bone-sparing procedure with long lasting biological fixation to the bone. We undertook a review of the literature examining advances of cementless TKA and the reported results.

Cite this article: Bone Joint J 2016;98-B:867–73.

INTRODUCTION. Cemented total knee arthroplasty (TKA) is a widely accepted treatment for end-stage knee osteoarthritis. During this procedure, the surgeon targets proper alignment of the leg and balanced flexion/extension gaps. However, the cement layer may impact the placement of the component, leading to changes in the mechanical alignment and gap size. The goal of the study was to assess the impact of cement layer on the tibial mechanical alignment and joint gap during cemented TKA. MATERIAL. Computer-assisted TKAs (ExactechGPS®, Blue-Ortho, Grenoble, FR) were performed by two fellowship trained orthorpaedic surgeons on five fresh-frozen non-arthritic pelvis-to-ankle cadaver legs. All the surgeries used a cemented cruciate retaining system (Optetrak Logic CR, Exactech, Gainesville, FL). After the bony resection, the proximal tibial resection plane was acquired by manually pressing an instrumented checker onto the resected tibial surface (resection plane). Once the prosthesis was implanted through standard cementing techniques, the top surface of the implanted tibial component was probed and recorded using an instrumented probe. A best fit plane was then calculated from the probed points and offset by the thickness of the prosthesis, representing the bottom plane of the component (component plane). The deviation of component alignment caused by the cement layer was calculated as the coronal and sagittal projection of the three-dimensional angle between the resection plane and the component plane. The deviation of the component height, reflecting a change in the joint gap, was assessed as the distance between the two planes calculated at the lowest points on the medial and lateral compartments of the proximal tibial surface. Statistical significance was defined as p≤0.05. RESULTS. The differences in alignment and component height between the tibial component placement and the ideal placement based on the bony resection are presented in Table 1. The magnitude of deviation in alignment was 1.2±0.9° for varus/valgus and 1.7±0.7° for posterior slope, with a tendency towards valgus (−0.2±1.6°) and reduced posterior slope (0.6±1.9°). The lateral compartment (2.4±0.9mm) had a generally higher increase in the height of the component compared to the medial compartment (1.0±0.9mm), the difference was close to being statistically significant (p=0.055). DISCUSSION. The finding of this study demonstrated that standard cement fixation during TKA may potentially influence the alignment and position of the tibial component. The formed cement layer generally results in elevated height, slightly more varus tibial alignment (overall limb valgus alignment) and less posterior slope in the implanted component. The results on the alignment are comparable to a previous study by Catani et al. [1]. More than 2°/2mm of deviation was found in the sagittal alignment (2 out of 5 knees), and medial (1 out of 5 knees) and lateral (3 out of 5 knees) component height, which may clinically impact the joint gap [2]. The varus/valgus alignment deviation found was clinically acceptable (≤3°). However when combined with other surgical variables, the accumulated impact on the alignment may warrant more investigation

Objectives

Initial stability of tibial trays is crucial for long-term success of total knee arthroplasty (TKA) in both primary and revision settings. Rotating platform (RP) designs reduce torque transfer at the tibiofemoral interface. We asked if this reduced torque transfer in RP designs resulted in subsequently reduced micromotion at the cemented fixation interface between the prosthesis component and the adjacent bone.

Introduction

Current clinical practice in total knee arthroplasty (TKA) is largely based on metal on polyethylene bearing couples. A potential adverse effect of the stiff metal femoral component is stress shielding, leading to loss of bone stock, periprosthetic bone fractures and eventually aseptic loosening of the component. The use of a polymer femoral component may address this problem. However, a more flexible material may also have consequences for the fixation of the femoral component. Concerns are raised about its expected potential to introduce local stress peaks on the interface.

The objective of this study was to analyze the effect of using a polyether-etherketone (PEEK-Optima®) femoral component on the cement-implant interface. We analyzed the interface stress distribution occurring during normal gait, and compared this to results of a standard CoCr component.

Stress shielding resulting in diminished bone density following total knee replacement (TKR) may increase the risk of migration and loosening of the prosthesis. This retrospective study was designed to quantify the effects of the method of fixation on peri-prosthetic tibial bone density beneath cemented and uncemented tibial components of similar design and with similar long-term survival rates. Standard radiographs taken between two months and 15 years post-operatively were digitised from a matched group of TKRs using cemented (n = 67) and uncemented (n = 67) AGC tibial prostheses. Digital radiograph densitometry was used to quantify changes in bone density over time. Age, length of follow-up, gender, body mass index and alignment each significantly influenced the long-term pattern of peri-prosthetic bone density. Similar long-term changes in density irrespective of the method of fixation correlated well with the high rate of survival of this TKR at 20 years, and suggest that cemented and uncemented fixation are both equally viable.

Cite this article: Bone Joint J 2013;95-B:911–16.

Objective. A study was performed in a tertiary health care centre to evaluate outcomes of arthroplasty in Indian Population. Various factors which may affect knee flexion after surgery were also evaluated. Methods. 82 patients with 60 unilateral & 22 bilateral total knee arthroplasties were included in the study. Assessment was done as per knee society knee score and function score. A simple functional questionaire including ability to squat, ability to sit cross leg, kneel while prayers, ability to use Indian toilet was filled and patients were rated accordingly as fair, good and excellent. Results. Average improvement in knee score was from 22.88 to 91.23 and function score from 16.26 to 73.59. Average range of motion improved from 80.4 to 125 degrees. Preoperative range of motion predicted final range of motion. There was significant improvement in flexion contracture (Mean 15.3 to 1.19). There was trend of increase in range of motion with time with no further gain reported after 1 year. Age, Sex, diagnosis, BMI, tibio- femoral angle did not of affect the final outcome. A Comparison was made between total condylar prosthesis & posterior stabilized prosthesis with no significant differences of outcomes between the two. 65% were rated excellent, 30% rated good & 5% fair as per functional questionaire given to the patients. Conclusion. Cemented total knee Arthroplasty provides pain relief, correction of deformity & restoration of function in inflammatory and degenerative arthritis. There is need to develop new functional scoring system for Indian population as knee society function score does not correspond to routine functional milestones of daily living achieved after total knee arthroplasty in Indian population

Cemented total knee arthroplasty has excellent long term survivorship however deficiencies of the cement mantle can compromise results. Minimising mantle deficiencies and increasing mantle size, may improve implant fixation and survivorship. The aim of this study was to evaluate the effectiveness of pressurized carbon dioxide lavage in an attempt to increase cement penetration into bone. Two consecutive series of TKAs where performed by the senior surgeon. During the first series standard cementing techniques where utilised prior to prosthesis implantation. The bone surfaces were cleaned with pulsatile lavage and then dried prior to cementation (n=69). During the second series a jet of high pressure carbon dioxide was also delivered to the bone surfaces via a hand held device (CarboJet, Kinamed Inc, Global Orthopaedic Technology)(n=50). A single investigator reviewed standardised post operative radiographs with respect to, depth of cement mantle around the prosthesis, and the presence of mantle defects. The cement mantle around the tibial and femoral prosthesis was divided into multiple zones, similar to that applied by the Knee Society. The depth of cement penetration was then measured for each zone in 0.5 mm increments using a 115% rule. Depths were averaged and then analysed using students’ T test. Cement penetration was greater with the use of pressurized carbon dioxide lavage. The greatest difference was seen in zones 1 and 4 beneath the Tibial prosthesis. A Significant difference was noted between groups. The size of the cement mantle can be increased with the use of pressurized carbon dioxide lavage. It is postulated that the bone interstices are cleared of fat and fluid more effectively than with fluid lavage alone. This may lead to an improved outcome for cemented total knee arthroplasty

Introduction: The aims of this study were to determine whether patients were transfused appropriately, after a Unilateral Cemented Primary Total Knee Replacement (TKR), and whether it would be cost effective to use autologous transfusion drains compared with standard group & save and cross match protocols.

Method: Retrospective study of the pre- and postoperative day 1 haemoglobin values of all patients who underwent unilateral primary cemented TKR between November 2004 – November 2005 at the Kent & Sussex Hospital, Tunbridge Wells. Haemoglobin data and length of stay was obtained from computerised records & transfusion data from the blood transfusion department.

Results: 150 patients were assessed: 97 (65%) female and 53 (35%) male. 20 (14.6%) patients required blood transfusion. The mean preoperative haemoglobin for non-transfused and transfused patient’s was 13.7 and 12.5g/dl respectively (P = 0.0029). The mean postoperative haemoglobin for non-transfused and transfused patient’s was 11.1 and 9.27g/dl respectively (P< 0.001). The mean blood loss for non-transfused and transfused patient’s was 2.64 and 3.26g/dl respectively (P< 0.001). There was no significant correlation between length of stay and either preoperative haemoglobin or blood loss after surgery; Spearman’s correlation coefficient was 0.0222 and 0.0036 respectively. The cost of a standard group & save and cross match, plus the 56 required units of blood in this study was £15,443.60. The theoretical cost of using a CellTrans Autologous Transfusion System on these 150 patients would be £14,355.00, a saving of only £1,088.60. However, by only using the autologous drains on patients with a preoperative haemoglobin ≤ 12.5g/dl, this saving could be increased to £4,131.20 per annum.

Conclusion: Using autologous transfusion drains on patients with a preoperative haemoglobin ≤ 12.5g/dl would save over £4,000 per annum at Maidstone & Tunbridge Wells Hospital Trust. There is no correlation between length of stay in hospital and either preoperative haemoglobin or blood loss after surgery. Patients transfused had significantly lower pre- and postoperative haemoglobins.

Introduction: Besides other techniques to reduce blood loss, the use of pneumatic tourniquet is commonly accepted in total knee arthroplasty (TKA). Furthermore it is used to maintain a clean and dry operative field to improve visualization, to use a better cementing technique, and to reduce operating time. The time of tourniquet release is discussed controversially in literature. However, there are only a few prospective randomised studies that compared the effect of timing of tourniquet release in cementless or cemented TKA. To our knowledge, this is the first study that investigated the influence of tourniquet release on blood loss in a randomized prospective study in simultaneous bilateral cemented TKA.

Methods: 20 patients (40 knees) underwent simultaneous bilateral cemented TKA with the cemented Triathlon Knee System (Stryker) between February and May 2006. The mean age of the patients was 67 years (67+/−11 years). 7 males and 13 females were treated with TKA (mean tourniquet pressure: 282.5+/−33.5 mm Hg). In 20 patients one knee was operated with tourniquet release and hemostasis before wound closure (“Technique A”), and the other knee with tourniquet release after wound closure and pressure dressing (“Technique B”). To determine the order of tourniquet release technique in simultaneous bilateral TKA, the patients were randomized in two groups: “Group A” (20 knees) first knee with tourniquet release and hemostasis before wound closure, and “Group B” (20 knees) second knee with tourniquet release and hemostasis before wound closure. The patients were given low molecular weight heparin and a leg dressing to prevent deep vein thrombosis. The blood loss was monitored two days after surgery till removal of the wound drains.

Results: We found no significant difference in total blood loss between “Technique A” (753+/−390 ml) and “Technique B” (760+/−343 ml) (p=.930). Furthermore there was no significant difference in total blood loss between both techniques after randomizing in “Group A” (“Technique A” 653+/−398 ml; “Technique B” 686+/−267 ml; p=.751) and “Group B” (“Technique A” 854+/−374 ml; “Technique B” 834+/−406 ml; p=.861). However, the operating time showed a significant difference between “Technique A” (58+/−18 minutes) and “Technique B” (51+/−17 minutes) (p=.035).

Discussion: In this study we compared the effect of timing of tourniquet release on perioperative blood loss in a randomized prospective study in simultaneous bilateral cemented TKA. Our results showed no significant difference of blood loss but a significant difference of operation time. Therefore, we recommend a tourniquet release after wound closure to reduce operating time and to minimize the risk of peri- and postoperative complications at approximately similarly blood loss between both techniques.

Introduction: Aseptic loosening of cemented total knee arthroplasties is still an unsolved problem. In this regard the adhesion strength of the metal-bone cement interface is of major interest.

Material und Methods: Cemented tibial components coated with a silica/silane interlayer system (n=8) were dynamically loaded within a knee-simulator (DIN ISO 14243). After loading, the components were cut by “high pressure water jet technique” (Fraunhofer Institute for Production Technology, Aachen, Germany) into 10 slices (thickness 5 mm each) parallel to the shaft axis according to a standardised protocol. To evaluate the metal-bone cement interface with regard to gaps and cement failure, the tibial slices were analysed by light and fluorescent microscopy. These data were matched with uncoated components (n=8).

Results: The coated tibial components yielded a significant reduction of gaps in the metal-bone cement interface (p < 0.05) as well as a highly significant reduction of cement mantle failure (p < 0.001).

Conclusion: With the help of the silica/silane coating, gaps in the metal-bone cement interface with consecutive early cement mantle failure due to mechanical overstressing can be significantly reduced.

Purpose: To assess the clinical utility of a computer-based program (discrete dynamic contour method of boundary refinement; Matlab®) to quantify the location and extent of periprosthetic osteolysis around cemented total knee arthroplasties.

Methods: The radiographs of 171 primary Anatomical Modular Knee arthroplasties were reviewed by three independent, blinded raters using Matlab® software program. The location, size (mm2), polyethylene sterilization technique, alignment, presence or absence of femoral osteolysis and patient characteristics was recorded.

Results: The mean duration of follow-up was 8.47 ± 1.10 years with minimum in vivo wear interval= 2.0 years. The overall incidence of radiographically apparent osteolysis was estimated at 30.41%. Furthermore, the average intra-class correlation coefficient for this measurement technique for three independent observers was found to be significant for medially and laterally located zones of osteolysis (I.C.C. value = .7801; 95% C.I. = .7161–.8316; (p< .05). There was a statistically significant trend towards higher rates of osteolysis occurring within the series of polyethylene inserts gamma irradiated in air. Lowest rates of osteolysis were measured in the series sterilized in gas plasma (27.09 mm2 per year vs. 16.24 mm2 per year respectively; p< .001).

Conclusions: The Discrete Dynamic Contour method of boundary refinement represents an acceptably reliable means by which one can quantify the location and extent of osteolysis based upon digitalized radiographs of total knee replacements.