We report a prospective study of gait and tibial component migration in 45 patients with osteoarthritis treated by total knee arthroplasty (TKA). Migration was measured over two years using roentgen stereophotogrammetry. We used the previously established threshold of 200 μm migration in the second postoperative year to distinguish two groups: a risk group of 15 patients and a stable group of 28 patients. We performed gait analysis before operation and at six months and at two years after TKA. On all three occasions we found significant differences between the two groups in the mean sagittal plane moments of the knee joint. The risk group walked with higher peak flexion moments than the stable group. The two groups were not discriminated by any clinical or radiological criteria or other gait characteristics. The relationship which we have found between gait with increased flexion moments and risk of
The outcomes of patients with unexpected positive cultures (UPCs) during revision total hip arthroplasty (THA) and total knee arthroplasty (TKA) remain unknown. The objectives of this study were to establish the prevalence and infection-free implant survival in UPCs during presumed aseptic single-stage revision THA and TKA at mid-term follow-up. This study included 297 patients undergoing presumed aseptic single-stage revision THA or TKA at a single treatment centre. All patients with at least three UPCs obtained during revision surgery were treated with minimum three months of oral antibiotics following revision surgery. The prevalence of UPCs and causative microorganisms, the recurrence of periprosthetic joint infections (PJIs), and the infection-free implant survival were established at minimum five years’ follow-up (5.1 to 12.3).Aims
Methods
Nonagenarians (aged 90 to 99 years) have experienced the fastest percent decile population growth in the USA recently, with a consequent increase in the prevalence of nonagenarians living with joint arthroplasties. As such, the number of revision total hip arthroplasties (THAs) and total knee arthroplasties (TKAs) in nonagenarians is expected to increase. We aimed to determine the mortality rate, implant survivorship, and complications of nonagenarians undergoing aseptic revision THAs and revision TKAs. Our institutional total joint registry was used to identify 96 nonagenarians who underwent 97 aseptic revisions (78 hips and 19 knees) between 1997 and 2018. The most common indications were aseptic loosening and periprosthetic fracture for both revision THAs and revision TKAs. Mean age at revision was 92 years (90 to 98), mean BMI was 27 kg/m2 (16 to 47), and 67% (n = 65) were female. Mean time between primary and revision was 18 years (SD 9). Kaplan-Meier survival was used for patient mortality, and compared to age- and sex-matched control populations. Reoperation risk was assessed using cumulative incidence with death as a competing risk. Mean follow-up was five years.Aims
Methods
Total femoral arthroplasty (TFA) is a rare procedure used in cases of significant femoral bone loss, commonly from cancer, infection, and trauma. Low patient numbers have resulted in limited published work on long-term outcomes, and even less regarding TFA undertaken for non-oncological indications. The aim of this study was to evaluate the long-term clinical outcomes of all TFAs in our unit. Data were collected retrospectively from a large tertiary referral revision arthroplasty unit’s database. Inclusion criteria included all patients who underwent TFA in our unit. Preoperative demographics, operative factors, and short- and long-term outcomes were collected for analysis. Outcome was defined using the Musculoskeletal Infection Society (MSIS) outcome reporting tool.Aims
Methods
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. Methods. 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. Results. Rotational malalignment between femoral and
Currently, the US Center for Medicaid and Medicare Services (CMS) has been testing bundled payments for revision total joint arthroplasty (TJA) through the Bundled Payment for Care Improvement (BPCI) programme. Under the BPCI, bundled payments for revision TJAs are defined on the basis of diagnosis-related groups (DRGs). However, these DRG-based bundled payment models may not be adequate to account appropriately for the varying case-complexity seen in revision TJAs. The 2008-2014 Medicare 5% Standard Analytical Files (SAF5) were used to identify patients undergoing revision TJA under DRG codes 466, 467, or 468. Generalized linear regression models were built to assess the independent marginal cost-impact of patient, procedural, and geographic characteristics on 90-day costs.Aims
Methods
The aim of this study was to conduct the largest low contact stress (LCS) retrieval study to elucidate the failure mechanisms of the Porocoat and Duofix femoral component. The latter design was voluntarily recalled by the manufacturer. Uncemented LCS explants were divided into three groups: Duofix, Porocoat, and mixed. Demographics, polyethylene wear, tissue ingrowth, and metallurgical analyses were performed.Aims
Materials and Methods
A consecutive series of 235 total knee arthroplasties using the PFC system was followed prospectively for at least ten years in 186 patients. The operation was for osteoarthritis in 150 knees, for rheumatoid arthritis in 83, and for Paget’s disease and femoral osteonecrosis in one knee each. At the latest review 56 patients had died, fi ve were too ill to assess and three could not be traced. The PFC knee replacement utilised was a nonconforming posterior-cruciate-retaining prosthesis with a polyethylene insert which is fl at in the sagittal plane. The patella was resurfaced using a metal-backed component in 170 cases, but later in the series we used an all-polyethylene component in 22 knees; 43 patellae were not resurfaced. The survival without need for reoperation for any reason was 90% at ten years. Nineteen revisions were component-related due to failure of nine metal-backed patellae, nine polyethylene inserts, and one unresurfaced patella; two reoperations were for synovectomy (one for recurrent haemarthrosis and one for recurrent rheumatoid synovitis) and three were for metastatic joint infection. There were no revisions for aseptic loosening of femoral or
The aim of this study was to give estimates of the incidence of component incompatibility in hip and knee arthroplasty and to test the effect of an online, real-time compatibility check. Intraoperative barcode registration of arthroplasty implants was introduced in Denmark in 2013. We developed a compatibility database and, from May 2017, real-time compatibility checking was implemented and became part of the registration. We defined four classes of component incompatibility: A-I, A-II, B-I, and B-II, depending on an assessment of the level of risk to the patient (A/B), and on whether incompatibility was knowingly accepted (I/II).Aims
Materials and Methods
Positive cultures are not uncommon in cases of revision total
knee and hip arthroplasty (TKA and THA) for presumed aseptic causes.
The purpose of this study was to assess the incidence of positive
intra-operative cultures in presumed aseptic revision of TKA and
THA, and to determine whether the presence of intra-operative positive cultures
results in inferior survival in such cases. A retrospective cohort study was assembled with 679 patients
undergoing revision knee (340 cases) or hip arthroplasty (339 cases)
for presumed aseptic causes. For all patients three or more separate
intra-operative cultures were obtained. Patients were diagnosed
with a previously unsuspected prosthetic joint infection (PJI) if two
or more cultures were positive with the same organism. Records were
reviewed for demographic details, pre-operative laboratory results
and culture results. The primary outcome measure was infection-free
implant survival at two years.Aims
Patients and Methods
Unicompartmental knee arthroplasty (UKA) is a potential treatment
for isolated bone on bone osteoarthritis when limited to a single
compartment. The risk for revision of UKA is three times higher
than for total knee arthroplasty (TKA). The aim of this review was
to discuss the different revision options after UKA failure. A search was performed for English language articles published
between 2006 and 2016. After reviewing titles and abstracts, 105
papers were selected for further analysis. Of these, 39 papers were
deemed to contain clinically relevant data to be included in this review.Objectives
Materials and Methods
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 soft tissues, and multiplanar deformities
may all be present in the valgus arthritic knee. A number of classifications
have been reported in order to guide surgical management, and a variety
of surgical strategies have been described with satisfactory clinical
results. Depending on the severity of the deformity, a variety of
TKA implant designs may be appropriate for use. Regardless of an operating surgeon’s preferred surgical strategy,
adherence to a step-wise approach to deformity correction is advised. Cite this article:
Collateral ligament release is advocated in total
knee arthroplasty (TKA) to deal with significant coronal plane deformities,
but is also associated with significant disadvantages. We describe steps to avoid release of the collateral (superficial
medial and lateral collateral) ligaments during TKA in severely
deformed knees, while correcting deformity and balancing the knee. Cite this article:
The Unified Classification System (UCS) was introduced
because of a growing need to have a standardised universal classification
system of periprosthetic fractures. It combines and simplifies many
existing classification systems, and can be applied to any fracture
around any partial or total joint replacement occurring during or
after operation. Our goal was to assess the inter- and intra-observer
reliability of the UCS in association with knee replacement when
classifying fractures affecting one or more of the femur, tibia
or patella. We used an international panel of ten orthopaedic surgeons with
subspecialty fellowship training and expertise in adult hip and
knee reconstruction (‘experts’) and ten residents of orthopaedic
surgery in the last two years of training (‘pre-experts’). They
each received 15 radiographs for evaluation. After six weeks they
evaluated the same radiographs again but in a different order. The reliability was assessed using the Kappa and weighted Kappa
values. The Kappa values for inter-observer reliability for the experts
and the pre-experts were 0.741 (95% confidence interval (CI) 0.707
to 0.774) and 0.765 (95% CI 0.733 to 0.797), respectively. The weighted
Kappa values for intra-observer reliability for the experts and
pre-experts were 0.898 (95% CI 0.846 to 0.950) and 0.878 (95% CI
0.815 to 0.942) respectively. The UCS has substantial inter-observer reliability and ‘near
perfect’ intra-observer reliability when used for periprosthetic
fractures in association with knee replacement in the hands of experienced
and inexperienced users. Cite this article:
The aim of our study was to describe the characteristics,
treatment, and outcomes of patients with periprosthetic joint infection
(PJI) and normal inflammatory markers after total knee arthroplasty
(TKA) and total hip arthroplasty (THA). In total 538 TKAs and 414 THAs underwent surgical treatment for
PJI and met the inclusion criteria. Pre-operative erythrocyte sedimentation
rate (ESR) and C-reactive protein level (CRP) were reviewed to identify
the seronegative cohort. An age- and gender-matched cohort was identified
from the remaining patients for comparison. Overall, 4% of confirmed
infections were seronegative (21 TKA and 17 THA). Of those who underwent
pre-operative aspiration, cultures were positive in 76% of TKAs
(n = 13) and 64% of THAs (n = 7). Cell count and differential were
suggestive of infection in 85% of TKA (n = 11) and all THA aspirates
(n = 5). The most common organism was coagulase-negative Cite this article:
As part of the government’s initiative to reduce waiting times for major joint surgery in Wales, the Cardiff and Vale NHS Trust sent 224 patients (258 knees) to the NHS Treatment Centre in Weston-Super-Mare for total knee replacement. The Kinemax total knee replacement system was used in all cases. The cumulative survival rate at three years was 79.2% (95% confidence interval (CI) 69.2 to 86.8) using re-operation for any cause as an endpoint and 85.3% (95% CI 75.9 to 91.8) using aseptic revision as an endpoint. This is significantly worse than that recorded in the published literature. These poor results have resulted in a significant impact on our service.
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.
We analysed data from the Oxford hip and knee questionnaires collected by the New Zealand Joint Registry at six months and five years after joint replacement, to determine if there was any relationship between the scores and the risk of early revision. Logistic regression of the six-month scores indicated that for every one-unit decrease in the Oxford score, the risk of revision within two years increased by 9.7% for total hip replacement (THR), 9.9% for total knee replacement (TKR) and 12.0% for unicompartmental knee replacement (UKR). Our findings showed that 70% of the revisions within two years for TKR and 67% for THR and UKR would have been captured by monitoring the lowest 22%, 28% and 28%, respectively, of the Oxford scores. When analysed using the Kalairajah classification a score of <
27 (poor) was associated with a risk of revision within two years of 7.6% for THR, 7.0% for TKR and 24.3% for UKR, compared with risks of 0.7%, 0.7% and 1.8%, respectively, for scores >
34 (good or excellent). Our study confirms that the Oxford hip and knee scores at six months are useful predictors of early revision after THR and TKR and we recommend their use for the monitoring of the outcome and potential failure in these patients.
