Varus-valgus constrained (VVC) implants are often used during revision total knee arthroplasty (TKA) to gain coronal plane stability. However, the increased mechanical torque applied to the bone-cement interface theoretically increases the risk of aseptic loosening. We assessed mid-term survivorship, complications, and clinical outcomes of a fixed-bearing VVC device in revision TKAs. A total of 416 consecutive revision TKAs (398 patients) were performed at our institution using a single fixed-bearing VVC TKA from 2007 to 2015. Mean age was 64 years (33 to 88) with 50% male (199). Index revision TKA diagnoses were: instability (n = 122, 29%), aseptic loosening (n = 105, 25%), and prosthetic joint infection (PJI) (n = 97, 23%). All devices were cemented on the epiphyseal surfaces. Femoral stems were used in 97% (n = 402) of cases, tibial stems in 95% (n = 394) of cases; all were cemented. In total, 93% (n = 389) of cases required a stemmed femoral and tibial component. Femoral cones were used in 29%, and tibial cones in 40%. Survivorship was assessed via competing risk analysis; clinical outcomes were determined using Knee Society Scores (KSSs) and range of movement (ROM). Mean follow-up was four years (2 to 10).Aims
Methods
Knee osteonecrosis in advanced stages may lead to joint degeneration. Total knee arthroplasty (TKA) for osteonecrosis has traditionally been associated with suboptimal results. We analyzed outcomes of contemporary TKAs for osteonecrosis, with particular emphasis on: survivorship free from aseptic loosening, any revision, and any reoperation plus the clinical outcomes, complications, and radiological results. In total, 156 patients undergoing 167 primary TKAs performed for osteonecrosis between 2004 and 2014 at a single institution were reviewed. The mean age at index TKA was 61 years (14 to 93) and the mean body mass index (BMI) was 30 kg/m2 (18 to 51) The mean follow-up was six years (2 to 12). A total of 110 TKAs (66%) were performed for primary osteonecrosis and 57 TKAs (34%) for secondary osteonecrosis. Overall, 15 TKAs (9%) had tibial stems, while 12 TKAs (7%) had femoral stems. Posterior-stabilized designs were used in 147 TKAs (88%) of TKAs. Bivariate Cox regression analysis was conducted to identify risk factors for revision and reoperation.Aims
Patients and Methods
While knee arthrodesis is a salvage option for recalcitrant total knee arthroplasty (TKA) periprosthetic joint infection (PJI) it is used relatively uncommonly and contemporary data are limited. We sought to determine the reliability, durability and safety of knee arthrodesis as the definitive treatment for complex, persistently infected TKA in a modern series of patients. We retrospectively identified 41 knees treated from 2002–2016 with a deliberate, two-stage knee arthrodesis protocol (TKA resection, high-dose antibiotic spacer, targeted IV antibiotics and followed by subsequent knee arthrodesis) in patients with complex TKA PJI. Mean age was 64 years & mean BMI was 39 kg/m2. Mean follow-up was 4 years. The extensor mechanism was deficient in 66% of knees, and flap coverage was required in 34% of knees. The majority of patients were host grade B (56%) or C (29%), and extremity grade of 3 (71%). Twenty-nine percent had poly-microbial infections, and 49% had multi-drug resistant organisms. Fixation included intramedullary nail (61%), external fixator (24%), and dual plating (15%).Introduction
Methods
Metaphyseal cones with cemented stems are frequently used in revision total knee arthroplasties (TKAs). However, if the diaphysis has been previously violated (as in revision of a failed stemmed implant), the resultant sclerotic canal can impair cemented stem fixation, which is vital for cone ingrowth and long-term fixation. We report the outcomes of our novel solution to this problem, in which impaction grafting and a cemented stem in the diaphysis was combined with an uncemented metaphyseal cone for revision TKAs with severely compromised bone. A metaphyseal cone was combined with diaphyseal impaction grafting and cemented stems in a novel fashion for 35 revision TKAs. Mean age at revision TKA was 70 years, with 63% being male. Patients had a mean of 4 prior knee arthroplasty procedures. Indications for the revision with this construct were aseptic loosening (80%) and two-stage re-implantation for periprosthetic infection (PJI; 20%). Mean follow-up was 3 years.Introduction
Methods
Periprosthetic joint infection (PJI) remains the main cause of failure in primary and revision total knee arthroplasties (TKAs). Local delivery of antibiotics, mainly antibiotic-loaded bone cement (ALBC), is commonly employed to prevent PJI. Over the past decade, tantalum and porous titanium have been successfully utilized as metaphyseal fixation devices to address bone loss and improve biologic fixation during revision TKA. However, no study has examined the antimicrobial properties compared to bone cement. The purpose of this study was to compare the ability of tantalum, 3D porous titanium, antibiotic-loaded bone cement (ALBC) and smooth titanium alloy (STA) to inhibit Staphylococci bacterial agents in an in vitro medium environment, based on the evaluation of the zone of inhibition (ZOI) and the antibacterial activity duration. Our study hypothesis was that we will found no significant difference between groups to inhibit Methicillin-Sensitive or Methicillin-Resistant Staphylococcus aureus (MSSA/MRSA) agents. Thirty beads made of 3 different materials (tantalum/ 3D porous titanium/ STA) were bathed during 1hour inside of a solution made of 1g vancomycin with 20-mL of sterile water for injection (bath concentration: 50 mg/mL). Ten 1cm3 cylinders were also created mixing standard surgical cement with 1g of Vancomycin in standardized sterile molds (ALBC beads). Finally, thirty beads made of tantalum/ 3D porous titanium/ STA were bathed in phosphate buffered saline solution to act as a control group. Cylinders were then placed on agar plates inoculated with MSSA and MRSA. Inhibition zone diameters were measured each day and cylinders were transferred onto a new inoculated plate. Inhibition zones were measured with a manual Vernier caliper and with automated software. The mean inhibition zones between groups were compared using the Wilcoxon Test.Introduction
Methods
Metaphyseal fixation during revision total knee arthroplasties (TKAs) is important, but potentially challenging with historical cone designs. Material and manufacturing innovations have improved the size and shape of cones available, and simplified requisite bone preparation. In a very large series, we assessed implant survivorship, radiographic results, and clinical outcomes of new porous 3-D printed titanium metaphyseal cones featuring a reamer-based system. We reviewed 142 revision TKAs using 202 cones (134 tibial and 68 femoral) from 2015 to 2016. Sixty cases involved tibial and femoral cones. Most cones (149 of 202; 74%) were used for Type 2B or 3 bone loss. Mean age was 66 years, with 54 % females. Mean BMI was 34 kg/m2. Patients had a mean of 2.4 prior surgeries and 48% had a history of periprosthetic infection. Mean follow-up was 2 years.Introduction
Methods
Primary total knee arthroplasties (TKA) performed in younger patients raise concerns regarding the potential for accelerated polyethylene wear, aseptic loosening, and thus revision TKA at a younger age. The purpose of this study was to determine the long-term implant survivorship, functional outcomes, and pain relief of primary TKA performed in patients under 35 years of age. A retrospective review of our institutional registry identified 185 TKAs performed in 119 patients under the age of 35 between 1985 and 2010. Medical records and radiographs were reviewed. Patients were contacted for two serial questionnaires in 2011–2012 and again in 2018. Implant survivorship was calculated using Kaplan-Meier survivorship curves and Cox proportional hazard model. The median age was 26.1 (21.5–30.1) years, with a BMI of 23.5 (20.4–26.6) kg/m2. Median follow-up was 13.9 (8.5–19.8) years.Introduction
Methods
Tranexamic acid (TXA) is proven to reduce blood loss following total knee arthroplasty (TKA), but there are limited data on the impact of similar dosing regimens in revision TKA. The purpose of this multicentre randomized clinical trial was to determine the optimal regimen to maximize the blood-sparing properties of TXA in revision TKA. From six-centres, 233 revision TKAs were randomized to one of four regimens: 1 g of intravenous (IV) TXA given prior to the skin incision, a double-dose regimen of 1 g IV TXA given both prior to skin incision and at time of wound closure, a combination of 1 g IV TXA given prior to skin incision and 1 g of intraoperative topical TXA, or three doses of 1950 mg oral TXA given two hours preoperatively, six hours postoperatively, and on the morning of postoperative day one. Randomization was performed based on the type of revision procedure to ensure equivalent distribution among groups. Power analysis determined that 40 patients per group were necessary to identify a 1 g/dl difference in the reduction of haemoglobin postoperatively between groups with an alpha of 0.05 and power of 0.80. Per-protocol analysis involved regression analysis and two one-sided Aims
Patients and Methods
The aims of this study were to compare the mean duration of antibiotic release and the mean zone of inhibition between vancomycin-loaded porous tantalum cylinders and antibiotic-loaded bone cement at intervals, and to evaluate potential intrinsic antimicrobial properties of tantalum in an Ten porous tantalum cylinders and ten cylinders of cement were used. The tantalum cylinders were impregnated with vancomycin, which was also added during preparation of the cylinders of cement. The cylinders were then placed on agar plates inoculated with MSSA. The diameter of the inhibition zone was measured each day, and the cylinders were transferred to a new inoculated plate. Inhibition zones were measured with a Vernier caliper and using an automated computed evaluation, and the intra- and interobserver reproducibility were measured. The mean inhibition zones between the two groups were compared with Wilcoxon’s test.Aims
Materials and Methods
There is little information regarding the risk of a patient developing prosthetic joint infection (PJI) after primary total knee arthroplasty (TKA) when the patient has previously experienced PJI of a TKA or total hip arthroplasty (THA) in another joint. The goal of this study was to compare the risk of PJI of primary TKA in this patient population against matched controls. We retrospectively reviewed 95 patients (102 primary TKAs) treated between 2000 and 2014 with a history of PJI in another TKA or THA. A total of 50 patients (53%) were female. Mean age was 69 years (45 to 88) with a mean body mass index (BMI) of 36 kg/m2 (22 to 59). In total, 27% of patients were on chronic antibiotic suppression. Mean follow-up was six years (2 to 16). We 1:3 matched these (for age, sex, BMI, and surgical year) to 306 primary TKAs performed in 306 patients with a THA or TKA of another joint without a subsequent PJI. Competing risk with death was used for statistical analysis. Multivariate analysis was followed to evaluate risk factors for PJI in the study cohort.Aims
Patients and Methods
There is little literature about total knee arthroplasty (TKA) after distal femoral osteotomy (DFO). Consequently, the purpose of this study was to analyze the outcomes of TKA after DFO, with particular emphasis on: survivorship free from aseptic loosening, revision, or any re-operation; complications; radiological results; and clinical outcome. We retrospectively reviewed 29 patients (17 women, 12 men) from our total joint registry who had undergone 31 cemented TKAs after a DFO between 2000 and 2012. Their mean age at TKA was 51 years (22 to 76) and their mean body mass index 32 kg/m2 (20 to 45). The mean time between DFO and TKA was ten years (2 to 20). The mean follow-up from TKA was ten years (2 to 16). The prostheses were posterior-stabilized in 77%, varus-valgus constraint (VVC) in 13%, and cruciate-retaining in 10%. While no patient had metaphyseal fixation (e.g. cones or sleeves), 16% needed a femoral stem.Aims
Patients and Methods
The results of irrigation and debridement with component retention (IDCR) in the treatment of acutely infected total knee arthroplasties (TKAs) have been variable. The aim of this study was to assess the outcome after IDCR when combined with chronic antibiotic suppression. We also evaluated survivorship free from subsequent infection, removal of the components, and death, as well as the risk factors for failure. This was a single-centre retrospective review of 134 infected primary TKAs that were treated with IDCR. Infections within four weeks of the procedure were defined as acute postoperative infections, and those occurring more than four weeks after the procedure with symptoms for less than three weeks were defined as acute haematogenous infections. Patients were treated with intravenous antibiotics for four to six weeks, followed by chronic oral antibiotic suppression. Estimates of survival were made using a competing risk analysis. The mean follow-up was five years (2.1 to 13).Aims
Patients and Methods
There is no literature regarding the risk of a patient developing PJI after primary TKA if the patient has previously experienced PJI of a TKA or THA in another joint. The goal of this study was to compare the risk of PJI of primary TKA in this patient population compared to matched controls. We retrospectively reviewed 95 patients (102 primary TKAs) from 2000–2014 with a history of a TKA or THA PJI in another joint. Mean age was 69 years; mean BMI was 36 kg/m2. 27% high-risk patients were on chronic antibiotic suppression. Mean follow-up was 6 years. We 1:3 matched (to age, sex, BMI, and surgical year) these to 306 primary TKAs performed in patients with a THA or TKA of another joint without a subsequent PJI. Competing risk with death was used for statistical analysis. Multivariate analysis was utilized to evaluate risk factors for PJI in the study cohort.Introduction
Methods
Tranexamic acid (TXA) is proven to reduce blood loss following total knee arthroplasty (TKA), but there are limited data on the impact of similar dosing regimens in revision TKA that is associated with greater blood loss. The purpose of this multi-center randomized trial was to determine the optimal regimen to maximize the blood-sparing properties of TXA in revision TKA. 233 Septic and aseptic revision TKA from six-centers were randomized to either receive 1g pre-incision intravenous (IV) TXA, 1g pre- and post-incision IV TXA, 1g pre-incision IV and 1g intra-operative topical TXA, or three doses of 1950mg oral TXA given 2 hours pre-operatively, 6 hours post-operatively, and the morning of postoperative day 1. Randomization was performed based on type of revision to ensure equivalent distribution among groups. The primary outcome was reduction in hemoglobin. Power analysis determined 40 patients per group were necessary to identify a 1g/dL difference with an alpha of 0.05 and beta of 0.80. Per-protocol analysis involved regression analysis and two one-sided t-tests for equivalence.Introduction
Methods
It has been suggested that mobile-bearing total knee arthroplasty
(TKA) might lead to better outcomes by accommodating some femorotibial
rotational mismatch, thereby reducing contact stresses and polyethylene
wear. The aim of this study was to determine whether there is a
difference between fixed- and mobile-bearing versions of a contemporary
TKA with respect to durability, range of movement (ROM) and function,
ten years postoperatively. A total of 240 patients who were enrolled in this randomized
controlled trial (RCT) underwent a primary cemented TKA with one
of three tibial components (all-polyethylene fixed-bearing, modular
metal-backed fixed-bearing and mobile-bearing). Patients were reviewed
at a median follow-up of ten years (IQR 9.2 to 10.4).Aims
Patients and Methods
Primary (or spontaneous) and secondary osteonecrosis of the knee
can lead to severe joint degeneration, for which either total or
unicompartmental arthroplasty may be considered. However, there
are limited studies analyzing outcomes of unicompartmental knee arthroplasties
(UKAs) for osteonecrosis involving an isolated compartment of the
knee. The aims of this study were to analyze outcomes of UKAs for
osteonecrosis with specific focus on 1) survivorship free of any
revision or reoperation, 2) risk factors for failure, 3) clinical outcomes,
and 4) complications. A total of 45 patients underwent 46 UKAs for knee osteonecrosis
between 2002 and 2014 at our institution (The Mayo Clinic, Rochester,
Minnesota). Twenty patients (44%) were female; the mean age of the
patients was 66 years, and mean body mass index (BMI) was 31 kg/m2. Of
the 46 UKAs, 44 (96%) were medial UKAs, and 35 (76%) were fixed-bearing
design. Mean mechanical axis postoperatively was 1.5° varus (0°
to 5° varus); 41 UKAs (89%) were performed for primary osteonecrosis.
Mean follow-up was five years (2 to 12)Aims
Patients and Methods
Patients with flexion instability after total knee arthroplasty
(TKA) often present with a recurrent effusion, which may be a haemarthrosis.
While the radiographic factors contributing to flexion instability
have been elucidated, the clinical diagnosis remains challenging.
Our aim, in this study, was to determine the mean white cell count
and differential profile in pre-operative aspirations of synovial
fluid in a consecutive series of patients undergoing revision TKA
for flexion instability. Between 2000 and 2010, 60 patients undergoing aseptic revision
TKA for flexion instability were identified. The results of the
pre-operative aspiration of synovial fluid were available for 53
patients (88%). These patients were 1:2 matched to 106 patients
who underwent aseptic TKA for indications other than flexion instability.
The mean age of the patients at revision TKA was 65 years (44 to
82) and 55% were women. The mean follow-up was 4.3 years (2 to 10.2).Aims
Patients and Methods
Advances in polyethylene (PE) in total hip arthroplasty
have led to interest and increased use of highly crosslinked PE
(HXLPE) in total knee arthroplasty (TKA). Biomechanical data suggest
improved wear characteristics for HXLPE inserts over conventional
PE in TKA. Short-term results from registry data and few clinical
trials are promising. Our aim is to present a review of the history
of HXLPEs, the use of HXLPE inserts in TKA, concerns regarding potential mechanical
complications, and a thorough review of the available biomechanical
and clinical data. Cite this article:
The number of revision total knee arthroplasties (TKA) that are
performed is expected to increase. However, previous reports of
the causes of failure after TKA are limited in that they report
the causes at specific institutions, which are often dependent on
referral patterns. Our aim was to report the most common indications
for re-operations and revisions in a large series of posterior-stabilised
TKAs undertaken at a single institution, excluding referrals from
elsewhere, which may bias the causes of failure. A total of 5098 TKAs which were undertaken between 2000 and 2012
were included in the study. Re-operations, revisions with modular
component exchange, and revisions with non-modular component replacement
or removal were identified from the medical records. The mean follow-up
was five years (two to 12).Aims
Patients and Methods
A key to the success of revision total knee arthroplasty
(TKA) is a safe surgical approach using an exposure that minimises
complications. In most patients, a medial parapatellar arthrotomy
with complete synovectomy is sufficient. If additional exposure
is needed, a quadriceps snip performed through the quadriceps tendon
often provides the additional exposure required. It is simple to
perform and does not alter the post-operative rehabilitative protocol.
In rare cases, in which additional exposure is needed, or when removal
of a cemented long-stemmed tibial component is required, a tibial
tubercle osteotomy (TTO) may be used. Given the risk of post-operative
extensor lag, a V-Y quadricepsplasty is rarely indicated and usually
considered only if TTO is not possible. Cite this article:
