While medial unicompartmental knee arthroplasty (UKA) is indicated
for patients with full-thickness cartilage loss, it is occasionally
used to treat those with partial-thickness loss. The aim of this
study was to investigate the five-year outcomes in a consecutive
series of UKAs used in patients with partial thickness cartilage
loss in the medial compartment of the knee. Between 2002 and 2014, 94 consecutive UKAs were undertaken in
90 patients with partial thickness cartilage loss and followed up
independently for a mean of six years (1 to 13). These patients
had partial thickness cartilage loss either on both femur and tibia
(13 knees), or on either the femur or the tibia, with full thickness
loss on the other surface of the joint (18 and 63 knees respectively).
Using propensity score analysis, these patients were matched 1:2 based
on age, gender and pre-operative Oxford Knee Score (OKS) with knees
with full thickness loss on both the femur and tibia. The functional
outcomes, implant survival and incidence of re-operations were assessed
at one, two and five years post-operatively. A subgroup of 36 knees
in 36 patients with partial thickness cartilage loss, who had pre-operative
MRI scans, was assessed to identify whether there were any factors
identified on MRI that predicted the outcome.Aims
Patients and Methods
Malrotation of the femoral component can result in post-operative complications in total knee arthroplasty (TKA), including patellar maltracking. Therefore, we used computational simulation to investigate the influence of femoral malrotation on contact stresses on the polyethylene (PE) insert and on the patellar button as well as on the forces on the collateral ligaments. Validated finite element (FE) models, for internal and external malrotations from 0° to 10° with regard to the neutral position, were developed to evaluate the effect of malrotation on the femoral component in TKA. Femoral malrotation in TKA on the knee joint was simulated in walking stance-phase gait and squat loading conditions.Objectives
Materials and Methods
The interest in unicompartmental knee arthroplasty (UKA) for
medial osteoarthritis has increased rapidly but the long-term follow-up
of the Oxford UKAs has yet to be analysed in non-designer centres.
We have examined our ten- to 15-year clinical and radiological follow-up
data for the Oxford Phase III UKAs. Between January 1999 and January 2005 a total of 138 consecutive
Oxford Phase III arthroplasties were performed by a single surgeon
in 129 patients for medial compartment osteoarthritis (71 right
and 67 left knees, mean age 72.0 years (47 to 91), mean body mass
index 28.2 (20.7 to 52.2)). Both clinical data and radiographs were
prospectively recorded and obtained at intervals. Of the 129 patients,
32 patients (32 knees) died, ten patients (12 knees) were not able
to take part in the final clinical and radiological assessment due
to physical and mental conditions, but via telephone interview it
was confirmed that none of these ten patients (12 knees) had a revision
of the knee arthroplasty. One patient (two knees) was lost to follow-up.Aims
Patients and Methods
Our aim was to compare kinematic with mechanical alignment in
total knee arthroplasty (TKA). We performed a prospective blinded randomised controlled trial
to compare the functional outcome of patients undergoing TKA in
mechanical alignment (MA) with those in kinematic alignment (KA).
A total of 71 patients undergoing TKA were randomised to either
kinematic (n = 36) or mechanical alignment (n = 35). Pre- and post-operative
hip-knee-ankle radiographs were analysed. The knee injury and osteoarthritis
outcome score (KOOS), American Knee Society Score, Short Form-36,
Euro-Qol (EQ-5D), range of movement (ROM), two minute walk, and timed
up and go tests were assessed pre-operatively and at six weeks,
three and six months and one year post-operatively.Aims
Patients and Methods
The purpose of the present study was to examine the long-term
fixation of a cemented fixed-bearing polished titanium tibial baseplate
(Genesis ll). Patients enrolled in a previous two-year prospective trial (n
= 35) were recalled at ten years. Available patients (n = 15) underwent
radiostereometric analysis (RSA) imaging in a supine position using
a conventional RSA protocol. Migration of the tibial component in
all planes was compared between initial and ten-year follow-up.
Outcome scores including the Knee Society Score, Western Ontario
and McMaster Universities Arthritis Index, 12-item Short Form Health
Survey, Forgotten Joint Score, and University of California, Los
Angeles Activity Score were recorded.Aims
Patients and Methods
The Bereiter trochleoplasty has been used in our unit for 12
years to manage recurrent patellar instability in patients with
severe trochlea dysplasia. The aim of this study was to document
the outcome of a large consecutive cohort of patients who have undergone
this operation. Between June 2002 and August 2013, 214 consecutive trochleoplasties
were carried out in 185 patients. There were 133 women and 52 men
with a mean age of 21.3 years (14 to 38). All patients were offered
yearly clinical and radiological follow-up. They completed the following
patient reported outcome scores (PROMs): International Knee Documentation
Committee subjective scale, the Kujala score, the Western Ontario
and McMaster Universities Arthritis Index score and the short-form
(SF)-12. Aims
Patients and Methods
Patient specific instrumentation (PSI) uses advanced
imaging of the knee (CT or MRI) to generate individualised cutting
blocks aimed to make the procedure of total knee arthroplasty (TKA)
more accurate and efficient. However, in this era of healthcare
cost consciousness, the value of new technologies needs to be critically
evaluated. There have been several comparative studies looking at
PSI Cite this article:
Total knee arthroplasty (TKA) is a cost effective
and extremely successful operation. As longevity increases, the demand
for primary TKA will continue to rise. The success and survivorship
of TKAs are dependent on the demographics of the patient, surgical
technique and implant-related factors. Currently the risk of failure of a TKA requiring revision surgery
ten years post-operatively is 5%. The most common indications for revision include aseptic loosening
(29.8%), infection (14.8%), and pain (9.5%). Revision surgery poses
considerable clinical burdens on patients and financial burdens
on healthcare systems. We present a current concepts review on the epidemiology of failed
TKAs using data from worldwide National Joint Registries. Cite this article:
This randomised trial evaluated the outcome of
a single design of unicompartmental arthroplasty of the knee (UKA) with
either a cemented all-polyethylene or a metal-backed modular tibial
component. A total of 63 knees in 45 patients (17 male, 28 female)
were included, 27 in the all-polyethylene group and 36 in the metal-backed
group. The mean age was 57.9 years (39.6 to 76.9). At a mean follow-up
of 6.4 years (5 to 9.9), 11 all-polyethylene components (41%) were
revised (at a mean of 5.8 years; 1.4 to 8.0) post-operatively and
two metal-backed components were revised (at one and five years).
One revision in both groups was for unexplained pain, one in the
metal-backed group was for progression of osteoarthritis. The others
in the all-polyethylene group were for aseptic loosening. The survivorship
at seven years calculated by the Kaplan–Meier method for the all-polyethylene
group was 56.5% (95% CI 31.9 to 75.2, number at risk 7) and for
the metal-backed group was 93.8% (95% CI 77.3 to 98.4, number at
risk 16) This difference was statistically significant (p <
0.001).
At the most recent follow-up, significantly better mean Western
Ontario and McMaster Universities Arthritis Index Scores were found
in the all-polyethylene group (13.4 This randomised study demonstrates that all-polyethylene components
in this design of fixed bearing UKA had unsatisfactory results with
significantly higher rates of failure before ten years compared
with the metal-back components. Cite this article:
The June 2015 Knee Roundup360 looks at: Cruciate substituting
We studied the bone mineral density (BMD) and
the bone mineral content (BMC) of the proximal tibia in patients with
a well-functioning uncemented Oxford medial compartment arthroplasty
using the Lunar iDXA bone densitometer. Our hypothesis was that
there would be decreased BMD and BMC adjacent to the tibial base
plate and increased BMD and BMC at the tip of the keel. There were 79 consecutive patients (33 men, 46 women) with a
mean age of 65 years (44 to 84) with a minimum two-year follow-up
(mean 2.6 years (2.0 to 5.0)) after unilateral arthroplasty, who
were scanned using a validated standard protocol where seven regions
of interest (ROI) were examined and compared with the contralateral
normal knee. All had well-functioning knees with a mean Oxford knee
score of 43 (14 to 48) and mean Knee Society function score of 90
(20 to 100), showing a correlation with the increasing scores and
higher BMC and BMD values in ROI 2 in the non-implanted knee relative
to the implanted knee (p = 0.013 and p = 0.015, respectively). The absolute and percentage changes in BMD and BMC were decreased
in all ROIs in the implanted knee compared with the non-implanted
knee, but this did not reach statistical significance. Bone loss
was markedly less than reported losses with total knee replacement. There was no significant association with side, although there
was a tendency for the BMC to decrease with age in men. The BMC
was less in the implanted side relative to the non-implanted side
in men compared with women in ROI 2 (p = 0.027), ROI 3 (p = 0.049)
and ROI 4 (p = 0.029). The uncemented Oxford medial compartment arthroplasty appears
to allow relative preservation of the BMC and BMD of the proximal
tibia, suggesting that the implant acts more physiologically than
total knee replacement. Peri-prosthetic bone loss is an important
factor in assessing long-term implant stability and survival, and
the results of this study are encouraging for the long-term outcome
of this arthroplasty. Cite this article:
This study demonstrates a significant correlation
between the American Knee Society (AKS) Clinical Rating System and
the Oxford Knee Score (OKS) and provides a validated prediction
tool to estimate score conversion. A total of 1022 patients were prospectively clinically assessed
five years after TKR and completed AKS assessments and an OKS questionnaire.
Multivariate regression analysis demonstrated significant correlations between
OKS and the AKS knee and function scores but a stronger correlation
(r = 0.68, p <
0.001) when using the sum of the AKS knee and
function scores. Addition of body mass index and age (other statistically
significant predictors of OKS) to the algorithm did not significantly
increase the predictive value. The simple regression model was used to predict the OKS in a
group of 236 patients who were clinically assessed nine to ten years
after TKR using the AKS system. The predicted OKS was compared with
actual OKS in the second group. Intra-class correlation demonstrated
excellent reliability (r = 0.81, 95% confidence intervals 0.75 to
0.85) for the combined knee and function score when used to predict
OKS. Our findings will facilitate comparison of outcome data from
studies and registries using either the OKS or the AKS scores and
may also be of value for those undertaking meta-analyses and systematic
reviews. Cite this article:
Sagittal alignment of the lumbosacral spine, and specifically pelvic incidence (PI), has been implicated in the development of spine pathology, but generally ignored with regards to diseases of the hip. We aimed to determine if increased PI is correlated with higher rates of hip osteoarthritis (HOA). The effect of PI on the development of knee osteoarthritis (KOA) was used as a negative control. We studied 400 well-preserved cadaveric skeletons ranging from 50 to 79 years of age at death. Each specimen’s OA of the hip and knee were graded using a previously described method. PI was measured from standardised lateral photographs of reconstructed pelvises. Multiple regression analysis was performed to determine the relationship between age and PI with HOA and KOA.Objectives
Methods
The routine use of patient reported outcome measures
(PROMs) in evaluating the outcome after arthroplasty by healthcare
organisations reflects a growing recognition of the importance of
patients’ perspectives in improving treatment. Although widely embraced
in the NHS, there are concerns that PROMs are being used beyond
their means due to a poor understanding of their limitations. This paper reviews some of the current challenges in using PROMs
to evaluate total knee arthroplasty. It highlights alternative methods
that have been used to improve the assessment of outcome. Cite this article:
We retrospectively reviewed 35 cemented unicompartmental knee replacements performed for medial unicompartmental osteoarthritis of the knee in 31 patients ≤50 years old (mean 46, 31 to 49). Patients were assessed clinically and radiologically using the Knee Society scores at a mean follow-up of 9.7 years (5 to 16) and survival at 12 years was calculated. The mean Knee Society Function Score improved from 54 points (25 to 64) pre-operatively to 89 (80 to 100) post-operatively (p <
0.0001). Six knees required revision, four for polyethylene wear treated with an isolated exchange of the tibial insert, one for aseptic loosening and one for progression of osteoarthritis. The 12-year survival according to Kaplan-Meier was 80.6% with revision for any reason as the endpoint. Despite encouraging clinical results, polyethylene wear remains a major concern affecting the survival of unicompartmental knee replacement in patients younger than 50.
We report ten-year clinical and radiological
follow-up data for the Sigma Press Fit Condylar total knee replacement system
(Sigma PFC TKR). Between October 1998 and October 1999 a total of
235 consecutive PFC Sigma TKRs were carried out in 203 patients.
Patients were seen at a specialist nurse-led clinic seven to ten
days before admission and at six and 18 months, three, five and
eight to ten years after surgery. Data were recorded prospectively
at each clinic visit. Radiographs were obtained at the five- and
eight- to ten-year follow-up appointments. Of the 203 patients,
147 (171 knees) were alive at ten years and 12 were lost to follow-up.
A total of eight knees (3.4%) were revised, five for infection and
three to change the polyethylene insert. The survival at ten years
with an endpoint of revision for any reason was 95.9%, and with
an endpoint of revision for aseptic failure was 98.7%. The mean
American Knee Society Score (AKSS) was 79 (10 to 99) at eight to
ten years, compared with 31 (2 to 62) pre-operatively. Of 109 knee
with radiographs reviewed, 47 knees had radiolucent lines but none
showed evidence of loosening. Cite this article:
We describe the results of cemented total hip replacement in 23 patients (23 hips) with active tuberculous arthritis of the hip with a mean follow-up of 4.7 years (4 to 7). In two patients the diagnosis was proved by pre-operative biopsy, whereas all others were diagnosed on a clinicoradiological basis with confirmation obtained by histopathological examination and polymerase chain reaction of tissue samples taken at the time of surgery. All patients received chemotherapy for at least three months before surgery and treatment was continued for a total of 18 months. Post-operative dislocation occurred in one patient and was managed successfully by closed reduction. No reactivation of the infection or loosening of the implant was recorded and function of the hip improved in all patients. Total hip replacement in the presence of active tuberculous arthritis of the hip is a safe procedure when pre-operative chemotherapy is commenced and continued for an extended period after operation.
The requirement for release of collateral ligaments to achieve a stable, balanced total knee replacement has been reported to arise in about 50% to 100% of procedures. This wide range reflects a lack of standardised quantitative indicators to determine the necessity for a release. Using recent advances in computerised navigation, we describe two navigational predictors which provide quantitative measures that can be used to identify the need for release. The first was the ability to restore the mechanical axis before any bone resection was performed and the second was the discrepancy in the measured medial and lateral joint spaces after the tibial osteotomy, but before any femoral resection. These predictors showed a significant association with the need for collateral ligament release (p <
0.001). The first predictor using the knee stress test in extension showed a sensitivity of 100% and a specificity of 98% and the second, the difference between medial and lateral gaps in millimetres, a sensitivity of 83% and a specificity of 95%. The use of the two navigational predictors meant that only ten of the 93 patients required collateral ligament release to achieve a stable, neutral knee.
