Valgus knee deformity can present a number of
unique surgical challenges for the total knee arthroplasty (TKA)
surgeon. Understanding the typical patterns of bone and soft-tissue pathology
in the valgus arthritic knee is critical for appropriate surgical
planning. This review aims to provide the knee arthroplasty surgeon
with an understanding of surgical management strategies for the
treatment of valgus knee arthritis. Lateral femoral and tibial deficiencies, contracted lateral soft
tissues, attenuated medial
Fungal periprosthetic joint infections (fPJIs) are rare complications, constituting only 1% of all PJIs. Neither a uniform definition for fPJI has been established, nor a standardized treatment regimen. Compared to bacterial PJI, there is little evidence for fPJI in the literature with divergent results. Hence, we implemented a novel treatment algorithm based on three-stage revision arthroplasty, with local and systemic antifungal therapy to optimize treatment for fPJI. From 2015 to 2018, a total of 18 patients with fPJI were included in a prospective, single-centre study (DKRS-ID 00020409). The diagnosis of PJI is based on the European Bone and Joint Infection Society definition of periprosthetic joint infections. The baseline parameters (age, sex, and BMI) and additional data (previous surgeries, pathogen spectrum, and Charlson Comorbidity Index) were recorded. A therapy protocol with three-stage revision, including a scheduled spacer exchange, was implemented. Systemic antifungal medication was administered throughout the entire treatment period and continued for six months after reimplantation. A minimum follow-up of 24 months was defined.Aims
Methods
Removal of infected components and culture-directed antibiotics are important for the successful treatment of chronic periprosthetic joint infection (PJI). However, as many as 27% of chronic PJI patients yield negative culture results. Although culture negativity has been thought of as a contraindication to one-stage revision, data supporting this assertion are limited. The aim of our study was to report on the clinical outcomes for one-stage and two-stage exchange arthroplasty performed in patients with chronic culture-negative PJI. A total of 105 consecutive patients who underwent revision arthroplasty for chronic culture-negative PJI were retrospectively evaluated. One-stage revision arthroplasty was performed in 30 patients, while 75 patients underwent two-stage exchange, with a minimum of one year's follow-up. Reinfection, re-revision for septic and aseptic reasons, amputation, readmission, mortality, and length of stay were compared between the two treatment strategies.Aims
Methods
Arthrofibrosis is a relatively common complication after joint injuries and surgery, particularly in the knee. The present study used a previously described and validated rabbit model to assess the biomechanical, histopathological, and molecular effects of the mast cell stabilizer ketotifen on surgically induced knee joint contractures in female rabbits. A group of 12 skeletally mature rabbits were randomly divided into two groups. One group received subcutaneous (SQ) saline, and a second group received SQ ketotifen injections. Biomechanical data were collected at eight, ten, 16, and 24 weeks. At the time of necropsy, posterior capsule tissue was collected for histopathological and gene expression analyses (messenger RNA (mRNA) and protein).Aims
Methods
The success rates of two-stage revision arthroplasty for infection have evolved since their early description. The implementation of internationally accepted outcome criteria led to the readjustment of such rates. However, patients who do not undergo reimplantation are usually set aside from these calculations. The aim of this study was to investigate the outcomes of two-stage revision arthroplasty when considering those who do not undergo reimplantation, and to investigate the characteristics of this subgroup. A retrospective cohort study was conducted. Patients with chronic hip or knee periprosthetic joint infection (PJI) treated with two-stage revision between January 2010 and October 2018, with a minimum follow-up of one year, were included. Variables including demography, morbidity, microbiology, and outcome were collected. The primary endpoint was the eradication of infection. Patients who did not undergo reimplantation were analyzed in order to characterize this subgroup better.Aims
Methods
In the absence of an identified organism, single-stage revision is contraindicated in prosthetic joint infection (PJI). However, no studies have examined the use of intra-articular antibiotics in combination with single-stage revision in these cases. In this study, we present the results of single-stage revision using intra-articular antibiotic infusion for treating culture-negative (CN) PJI. A retrospective analysis between 2009 and 2016 included 51 patients with CN PJI who underwent single-stage revision using intra-articular antibiotic infusion; these were compared with 192 culture-positive (CP) patients. CN patients were treated according to a protocol including intravenous vancomycin and a direct intra-articular infusion of imipenem and vancomycin alternately used in the morning and afternoon. In the CP patients, pathogen-sensitive intravenous (IV) antibiotics were administered for a mean of 16 days (12 to 21), and for resistant cases, additional intra-articular antibiotics were used. The infection healing rate, Harris Hip Score (HHS), and Hospital for Special Surgery (HSS) knee score were compared between CN and CP groups.Aims
Methods
The aim of this study was to identify the incidence of positive
cultures during the second stage of a two-stage revision arthroplasty
and to analyse the association between positive cultures and an
infection-free outcome. This single-centre retrospective review of prospectively collected
data included patients with a periprosthetic joint infection (PJI)
of either the hip or the knee between 2013 and 2015, who were treated
using a standardised diagnostic and therapeutic algorithm with two-stage
exchange. Failure of treatment was assessed according to a definition
determined by a Delphi-based consensus. Logistic regression analysis
was performed to assess the predictors of positive culture and risk
factors for failure. The mean follow-up was 33 months (24 to 48).Aims
Patients and Methods
Computed tomography (CT) plays an important role in evaluating wear and periacetabular osteolysis (PAO) in total hip replacements. One concern with CT is the high radiation exposure since standard pelvic CT provides approximately 3.5 millisieverts (mSv) of radiation exposure, whereas a planar radiographic examination with three projections totals approximately 0.5 mSv. The objective of this study was to evaluate the lowest acceptable radiation dose for dual-energy CT (DECT) images when measuring wear and periacetabular osteolysis in uncemented metal components. A porcine pelvis with bilateral uncemented hip prostheses and with known linear wear and acetabular bone defects was examined in a third-generation multidetector DECT scanner. The examinations were performed with four different radiation levels both with and without iterative reconstruction techniques. From the high and low peak kilo voltage acquisitions, polychrmoatic images were created together with virtual monochromatic images of energies 100 kiloelectron volts (keV) and 150 keV.Objectives
Materials and Methods
Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA. In this pilot study, 16 patients with primary THA were recruited (eight MoM, eight MoP). DCE-MRI of the hip was performed at 1.5 Tesla (T). For each patient, Ktrans was computed voxel-by-voxel in all tissue lateral to the bladder. The mean Ktrans for all voxels was then calculated. These values were compared with respect to implant type and gender, and further correlated with clinical parameters.Objectives
Methods
To investigate the outcomes of treatment of streptococcal periprosthetic
joint infection (PJI) involving total knee and hip arthroplasties. Streptococcal PJI episodes which occurred between January 2009
and December 2015 were identified from clinical databases. Presentation
and clinical outcomes for 30 streptococcal PJIs in 30 patients (12
hip and 18 knee arthroplasties) following treatment were evaluated
from the medical notes and at review. The Kaplan-Meier survival method
was used to estimate the probability of infection-free survival.
The influence of the biofilm active antibiotic rifampin was also
assessed.Aims
Patients and Methods
Tissue responses to debris formed by abrasion of polymethylmethacrylate
(PMMA) spacers at two-stage revision arthroplasty for prosthetic
joint infection are not well described. We hypothesised that PMMA
debris induces immunomodulation in periprosthetic tissues. Samples of tissue were taken during 35 two-stage revision arthroplasties
(nine total hip and 26 total knee arthroplasties) in patients whose
mean age was 67 years (44 to 85). Fourier transform infrared microscopy
was used to confirm the presence of PMMA particles. Histomorphometry
was performed using Sudan Red and Haematoxylin-Eosin staining.
CD-68, CD-20, CD-11(c), CD-3 and IL-17 antibodies were used to immunophenotype
the inflammatory cells. All slides were scored semi-quantitatively
using the modified Willert scoring system.Aims
Patients and Methods
Wound complications are reported in up to 10% hip and knee arthroplasties and there is a proven association between wound complications and deep prosthetic infections. In this randomised controlled trial (RCT) we explore the potential benefits of a portable, single use, incisional negative pressure wound therapy dressing (iNPWTd) on wound exudate, length of stay (LOS), wound complications, dressing changes and cost-effectiveness following total hip and knee arthroplasties. A total of 220 patients undergoing elective primary total hip and knee arthroplasties were recruited into in a non-blinded RCT. For the final analysis there were 102 patients in the study group and 107 in the control group.Objectives
Methods
Nylon sutures and skin staples are used commonly in total knee arthroplasty (TKA) surgical wound closure. However, there is no study that compares the wound healing efficacy and patient satisfaction scores of both techniques in the same knee. We randomised 70 patients who underwent primary TKA into two groups. In one group of 34 patients, the skin at the upper half of the wound was closed with skin staples and the lower half of the wound was closed with simple interrupted nylon sutures. In the other group of 36 patients, the skin at the upper half of the wound was closed with nylon stitches and the lower half of the wound was closed with skin staples. We recorded the wound closure time, pain score at the time of stitch removal, wound complication rate, patient satisfaction score, and the Hollander wound evaluation score at the post-operative periods of five days, 14 days, six weeks, three months, and six months. Each half wound was analysed separately.Objectives
Methods
During the last ten years, greater attention
has been given to the management of peri-operative blood loss after
total knee arthroplasty (TKA), as it is a modifiable outcome that has
a significant effect on the rate of complications, the recovery,
and the economic burden. Blood loss after TKA has been greatly reduced
during this time, thereby dramatically reducing the rates of allogeneic
transfusion. This has significantly reduced the complications associated
with transfusion, such as fluid overload, infection, and increased length
of stay. The greatest advent in lowering peri-operative blood loss after
TKA has been the introduction of tranexamic acid, which reduces
blood loss without increasing the risk of thromboembolic events. This paper discusses the ways of reducing blood loss after TKA,
for which a multimodal algorithm, with pre-, intra- and post-operative
measures, has been adopted at our institution. Cite this article:
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. Composite tibias were implanted with fixed and RP primary and revision tibial trays and biomechanically tested under up to 2.5 kN of axial compression and 10° of external femoral component rotation. Relative micromotion between the implanted tibial tray and the neighbouring bone was quantified using high-precision digital image correlation techniques.Objectives
Methods
We describe the application of a non-invasive extendible endoprosthetic replacement in skeletally-mature patients undergoing revision for failed joint replacement with resultant limb-length inequality after malignant or non-malignant disease. This prosthesis was developed for tumour surgery in skeletally-immature patients but has now been adapted for use in revision procedures to reconstruct the joint or facilitate an arthrodesis, replace bony defects and allow limb length to be restored gradually in the post-operative period. We record the short-term results in nine patients who have had this procedure after multiple previous reconstructive operations. In six, the initial reconstruction had been performed with either allograft or endoprosthetic replacement for neoplastic disease and in three for non-neoplastic disease. The essential components of the prosthesis are a magnetic disc, a gearbox and a drive screw which allows painless lengthening of the prosthesis using the principle of electromagnetic induction. The mean age of the patients was 37 years (18 to 68) with a mean follow-up of 34 months (12 to 62). They had previously undergone a mean of six (2 to 14) open procedures on the affected limb before revision with the non-invasive extendible endoprosthesis. The mean length gained was 56 mm (19 to 107) requiring a mean of nine (3 to 20) lengthening episodes performed in the outpatient department. There was one case of recurrent infection after revision of a previously infected implant and one fracture of the prosthesis after a fall. No amputations were performed. Planned exchange of the prosthesis was required in three patients after attainment of the maximum lengthening capacity of the implant. There was no failure of the lengthening mechanism. The Mean Musculoskeletal Tumour Society rating score was 22 of 30 available points (18 to 28). The use of a non-invasive extendible endoprosthesis in this manner provided patients with good functional results and restoration of leg-length equality, without the need for multiple open lengthening procedures.
Because posterior cruciate ligament (PCL) resection makes flexion
gaps wider in total knee replacement (TKR), preserving or sacrificing
a PCL affects the gap equivalence; however, there are no criteria
for the PCL resection that consider gap situations of each knee.
This study aims to investigate gap characteristics of knees and
to consider the criteria for PCL resection. The extension and flexion gaps were measured, first with the
PCL preserved and subsequently with the PCL removed (in cases in
which posterior substitute components were selected). The PCL preservation
or sacrifice was solely determined by the gap measurement results,
without considering other functions of the PCL such as ‘roll back.’Objectives
Methods
We have recently shown that waste heat from forced-air
warming blankets can increase the temperature and concentration
of airborne particles over the surgical site. The mechanism for
the increased concentration of particles and their site of origin
remained unclear. We therefore attempted to visualise the airflow
in theatre over a simulated total knee replacement using neutral-buoyancy
helium bubbles. Particles were created using a Rocket PS23 smoke
machine positioned below the operating table, a potential area of
contamination. The same theatre set-up, warming devices and controls
were used as in our previous study. This demonstrated that waste
heat from the poorly insulated forced-air warming blanket increased
the air temperature on the surgical side of the drape by >
5°C.
This created convection currents that rose against the downward
unidirectional airflow, causing turbulence over the patient. The
convection currents increased the particle concentration 1000-fold
(2 174 000 particles/m3 for forced-air warming Cite this article:
Infection remains a significant and common complication after joint replacement and there is debate about which contributing factors are important. Few studies have investigated the effect of the operating time on infection. We collected data prospectively from 5277 hip and knee replacements which included the type of procedure, the operating time, the use of drains, the operating theatre, surgeon, age and gender. In a subgroup of 3449 knee replacements further analysis was carried out using the tourniquet time in place of the operating time. These variables were assessed by the use of generalised linear modelling against superficial, deep or joint-space post-operative infection as defined by the Australian Surgical-Site Infection criteria. The overall infection rate was 0.98%. In the replacement data set both male gender (z = 3.097, p = 0.00195) and prolonged operating time (z = 4.325, p <
0.001) were predictive of infection. In the knee subgroup male gender (z = 2.250, p = 0.02447), a longer tourniquet time (z = 2.867, p = 0.00414) and total knee replacement ( These findings support the view that a prolonged operating time and male gender are associated with an increased incidence of infection. Steps to minimise intra-operative delay should be instigated, and care should be exercised when introducing measures which prolong the duration of joint replacement.
The purpose of this study was to compare the
diagnostic accuracy for the detection of infection between the culture of
fluid obtained by sonication (SFC) and the culture of peri-implant
tissues (PITC) in patients with early and delayed implant failure,
and those with unsuspected and suspected septic failure. It was
hypothesised that SFC increases the diagnostic accuracy for infection
in delayed, but not early, implant failure, and in unsuspected septic
failure. The diagnostic accuracy for infection of all consecutive
implants (hardware or prostheses) that were removed for failure was
compared between SFC and PITC. This prospective study included 317
patients with a mean age of 62.7 years (9 to 97). The sensitivity
for detection of infection using SFC was higher than using PITC
in an overall comparison (89.9% Sonication is mainly recommended when there is implant failure
with no clear signs of infection and in patients with delayed implant
failure. In early failure, SFC is not superior to PITC for the diagnosis
of infection and, therefore, is not recommended as a routine diagnostic
test in these patients. Cite this article:
The lateral subvastus approach combined with an osteotomy of the tibial tubercle is a recognised, but rarely used approach for total knee replacement (TKR). A total of 32 patients undergoing primary TKR was randomised into two groups, in one of which the lateral subvastus approach combined with a tibial tubercle osteotomy and in the other the medial parapatellar approach were used. The patients were assessed radiologically and clinically using measurement of the range of movement, a visual analogue patient satisfaction score, the Western Ontario McMasters University Osteoarthritis Index and the American Knee Society score. Four patients were lost to the complete follow-up at two years. At two years there were no significant differences between the groups in any of the parameters for clinical outcome. In the lateral approach group there was one complication due to displacement of the tibial tubercle osteotomy and two osteotomies took more than six months to unite. In the medial approach group, one patient had a partial tear of the quadriceps. There was a significantly greater incidence of lateral patellar subluxation in the medial approach group (3 of 12) compared with the lateral approach group (0 of 16) (p = 0.034), but without any apparent clinical detriment. We conclude that the lateral approach with tibial tubercle osteotomy is a safe technique with an outcome comparable with that of the medial parapatellar approach for TKR, but the increased surgical time and its specific complications do not support its routine use. It would seem to be more appropriate to reserve this technique for patients in whom problems with patellar tracking are anticipated.
Implantation of allograft bone is an integral part of revision surgery of the hip. One major concern with its use is the risk of transmission of infective agents. There are a number of methods of processing allograft bone in order to reduce this risk. One method requires washing the tissue using pulsed irrigation immediately before implantation. We report the incidence of deep bacterial infection in 138 patients (144 revision hip arthroplasties) who had undergone implantation of allograft bone. The bone used was fresh-frozen, non-irradiated and pulse-washed with normal saline before implantation. The deep infection rate at a minimum follow-up of one year was 0.7%. This method of processing appears to be associated with a very low risk of allograft-related bacterial infection.
