Current analysis of unicondylar knee replacements
(UKRs) by national registries is based on the pooled results of medial
and lateral implants. Consequently, little is known about the differential
performance of medial and lateral replacements and the influence
of each implant type within these pooled analyses. Using data from
the National Joint Registry for England and Wales (NJR) we aimed
to determine the proportion of UKRs implanted on the lateral side
of the knee, and their survival and reason for failure compared
with medial UKRs. By combining information on the side of operation
with component details held on the NJR, we were able to determine
implant laterality (medial
We have performed a prospective double-blind, randomised controlled trial over two years to evaluate the efficacy and safety of an intra-operative peri-articular injection of triamcinolone acetonide in patients undergoing medial
Aims. The treatment of patients with allergies to metal in total joint arthroplasty is an ongoing debate. Possibilities include the use of hypoallergenic prostheses, as well as the use of standard cobalt-chromium (CoCr) alloy. This non-designer study was performed to evaluate the clinical outcome and survival rates of
Following arthroplasty of the knee, the patient’s
perception of improvement in symptoms is fundamental to the assessment
of outcome. Better clinical outcome may offset the inferior survival
observed for some types of implant. By examining linked National
Joint Registry (NJR) and patient-reported outcome measures (PROMs)
data, we aimed to compare PROMs collected at a minimum of six months
post-operatively for total (TKR: n = 23 393) and unicondylar knee
replacements (UKR: n = 505). Improvements in knee-specific (Oxford
knee score, OKS) and generic (EuroQol, EQ-5D) scores were compared
and adjusted for case-mix differences using multiple regression.
Whereas the improvements in the OKS and EQ-5D were significantly
greater for TKR than for UKR, once adjustments were made for case-mix
differences and pre-operative score, the improvements in the two
scores were not significantly different. The adjusted mean differences
in the improvement of OKS and EQ-5D were 0.0 (95% confidence interval (CI)
-0.9 to 0.9; p = 0.96) and 0.009 (95% CI -0.034 to 0.015; p = 0.37),
respectively. We found no difference in the improvement of either knee-specific
or general health outcomes between TKR and UKR in a large cohort
of registry patients. With concerns about significantly higher revision
rates for UKR observed in worldwide registries, we question the
widespread use of an arthroplasty that does not confer a significant
benefit in clinical outcome.
The aim of this independent multicentre study was to assess the
mid-term results of mobile bearing unicondylar knee arthroplasty
(UKA) for isolated lateral osteoarthritis of the knee joint. We retrospectively evaluated 363 consecutive, lateral UKAs (346
patients) performed using the Oxford domed lateral prosthesis undertaken
in three high-volume knee arthroplasty centres between 2006 and
2014. Mean age of the patients at surgery was 65 years (36 to 88)
with a mean final follow-up of 37 months (12 to 93)Aims
Patients and Methods
A fracture of the medial tibial plateau is a serious complication of Oxford mobile-bearing unicompartmental knee arthroplasty (OUKA). The risk of these fractures is reportedly lower when using components with a longer keel-cortex distance (KCDs). The aim of this study was to examine how slight varus placement of the tibial component might affect the KCDs, and the rate of tibial plateau fracture, in a clinical setting. This retrospective study included 255 patients who underwent 305 OUKAs with cementless tibial components. There were 52 males and 203 females. Their mean age was 73.1 years (47 to 91), and the mean follow-up was 1.9 years (1.0 to 2.0). In 217 knees in 187 patients in the conventional group, tibial cuts were made orthogonally to the tibial axis. The varus group included 88 knees in 68 patients, and tibial cuts were made slightly varus using a new osteotomy guide. Anterior and posterior KCDs and the origins of fracture lines were assessed using 3D CT scans one week postoperatively. The KCDs and rate of fracture were compared between the two groups.Aims
Methods
The December 2023 Knee Roundup. 360. looks at: Obesity is associated with greater improvement in patient-reported outcomes following primary total knee arthroplasty; Does mild flexion of the femoral prosthesis in total knee arthroplasty result in better early postoperative outcomes?; Robotic or manual total knee arthroplasty: a randomized controlled trial; Patient-relevant outcomes following first revision total knee arthroplasty, by diagnosis: an analysis of implant survivorship, mortality, serious medical complications, and patient-reported outcome measures using the National Joint Registry data set; Sagittal alignment in total knee arthroplasty: are there any discrepancies between robotic-assisted and manual axis orientation?; Tourniquet use does not impact recovery trajectory in total knee arthroplasty; Impact of proximal tibial varus anatomy on survivorship after medial
Aims. The aim of this study was to determine the risk of tibial eminence avulsion intraoperatively for bi-unicondylar knee arthroplasty (Bi-UKA), with consideration of the effect of implant positioning, overstuffing, and sex, compared to the risk for isolated medial
The June 2024 Knee Roundup. 360. looks at: The estimated lifetime risk of revision after primary knee arthroplasty influenced by age, sex, and indication; Should high-risk patients seek out care from high-volume surgeons?; Stability and fracture rates in medial
We identified 148 patients who had undergone a revision total knee replacement using a single implant system between 1990 and 2000. Of these 18 patients had died, six had developed a peri-prosthetic fracture and ten had incomplete records or radiographs. This left 114 with prospectively-collected radiographs and Bristol knee scores available for study. The height of the joint line before and after revision total knee replacement was measured and classified as either restored to within 5 mm of the pre-operative height or elevated if it was positioned more than 5 mm above the pre-operative height. The joint line was elevated in 41 knees (36%) and restored in 73 (64%). Revision surgery significantly improved the mean Bristol knee score from 41.1 (. sd. 15.9) pre-operatively to 80.5 (. sd. 15) post-operatively (p <
0.001). At one year post-operatively both the total Bristol knee score and its functional component were significantly better in the restored group than in the elevated group (p <
0.01). Overall, revision from a
Patellofemoral joint degeneration is often considered a contraindication to medial unicompartmental knee replacement. We examined the validity of this preconception using information gathered prospectively on the intra-operative status of the patellofemoral joint in 824 knees in 793 consecutive patients who underwent Oxford
Total knee arthroplasty (TKA) is a major orthopaedic
intervention. The length of a patient's stay has been progressively
reduced with the introduction of enhanced recovery protocols: day-case
surgery has become the ultimate challenge. This narrative review shows the potential limitations of day-case
TKA. These constraints may be social, linked to patient’s comorbidities,
or due to surgery-related adverse events (e.g. pain, post-operative
nausea and vomiting, etc.). . Using patient stratification, tailored surgical techniques and
multimodal opioid-sparing analgesia, day-case TKA might be achievable
in a limited group of patients. The younger, male patient without
comorbidities and with an excellent social network around him might
be a candidate. Demographic changes, effective recovery programmes and less invasive
surgical techniques such as
Although it has been suggested that the outcome
after revision of a
Osteoarthritis of the medial compartment of the knee often shows a specific pattern of anterior wear. Review of our revisions from a series of medial metal-backed Brigham
Narrow, well-defined radiolucent lines commonly observed at the bone-implant interface of unicompartmental knee replacement tibial components have been referred to as physiological radiolucencies. These should be distinguished from pathological radiolucencies, which are poorly defined, wide and progressive, and associated with loosening and infection. We studied the incidence and clinical significance of tibial radiolucent lines in 161 Oxford
Total knee arthroplasty (TKA) may provoke ankle symptoms. The aim of this study was to validate the impact of the preoperative mechanical tibiofemoral angle (mTFA), the talar tilt (TT) on ankle symptoms after TKA, and assess changes in the range of motion (ROM) of the subtalar joint, foot posture, and ankle laxity. Patients who underwent TKA from September 2020 to September 2021 were prospectively included. Inclusion criteria were primary end-stage osteoarthritis (Kellgren-Lawrence stage IV) of the knee. Exclusion criteria were missed follow-up visit, post-traumatic pathologies of the foot, and neurological disorders. Radiological angles measured included the mTFA, hindfoot alignment view angle, and TT. The Foot Function Index (FFI) score was assessed. Gait analyses were conducted to measure mediolateral changes of the gait line and ankle laxity was tested using an ankle arthrometer. All parameters were acquired one week pre- and three months postoperatively.Aims
Methods
The rate of day-case total knee arthroplasty (TKA) in the UK is currently approximately 0.5%. Reducing length of stay allows orthopaedic providers to improve efficiency, increase operative throughput, and tackle the rising demand for joint arthroplasty surgery and the COVID-19-related backlog. Here, we report safe delivery of day-case TKA in an NHS trust via inpatient wards with no additional resources. Day-case TKAs, defined as patients discharged on the same calendar day as surgery, were retrospectively reviewed with a minimum follow-up of six months. Analysis of hospital and primary care records was performed to determine readmission and reattendance rates. Telephone interviews were conducted to determine patient satisfaction.Aims
Methods
This study was performed to investigate the association between the acetabular morphology and the joint space narrowing rate (JSNR) in the non-arthritic hip. We retrospectively reviewed standing whole-leg radiographs of patients who underwent knee arthroplasty from February 2012 to March 2020 at our institute. Patients with a history of hip surgery, Kellgren-Lawrence grade ≥ II hip osteoarthritis, or rheumatoid arthritis were excluded. The hip JSNR was measured, and the normalized JSNR (nJSNR) was calculated by calibrating the joint space width with the size of the femoral head in 395 patients (790 hips) with a mean age of 73.7 years (SD 8.6). The effects of the lateral centre-edge angle (CEA) and acetabular roof obliquity (ARO) in the standing and supine positions were examined using a multivariate regression model.Aims
Methods
The preventive effects of bisphosphonates on articular cartilage in non-arthritic joints are unclear. This study aimed to investigate the effects of oral bisphosphonates on the rate of joint space narrowing in the non-arthritic hip. We retrospectively reviewed standing whole-leg radiographs from patients who underwent knee arthroplasties from 2012 to 2020 at our institute. Patients with previous hip surgery, Kellgren–Lawrence grade ≥ II hip osteoarthritis, hip dysplasia, or rheumatoid arthritis were excluded. The rate of hip joint space narrowing was measured in 398 patients (796 hips), and the effects of the use of bisphosphonates were examined using the multivariate regression model and the propensity score matching (1:2) model.Aims
Methods
Unicompartmental and total knee arthroplasty (UKA and TKA) are successful treatments for osteoarthritis, but the solid metal implants disrupt the natural distribution of stress and strain which can lead to bone loss over time. This generates problems if the implant needs to be revised. This study investigates whether titanium lattice UKA and TKA implants can maintain natural load transfer in the proximal tibia. In a cadaveric model, UKA and TKA procedures were performed on eight fresh-frozen knee specimens, using conventional (solid) and titanium lattice tibial implants. Stress at the bone-implant interfaces were measured and compared to the native knee.Aims
Methods
Knee arthroplasty surgery is a highly effective treatment for arthritis and disorders of the knee. There are a wide variety of implant brands and types of knee arthroplasty available to surgeons. As a result of a number of highly publicized failures, arthroplasty surgery is highly regulated in the UK and many other countries through national registries, introduced to monitor implant performance, surgeons, and hospitals. With time, the options available within many brand portfolios have grown, with alternative tibial or femoral components, tibial insert materials, or shapes and patella resurfacings. In this study we have investigated the effect of the expansion of implant brand portfolios and where there may be a lack of transparency around a brand name. We also aimed to establish the potential numbers of compatible implant construct combinations. Hypothetical implant brand portfolios were proposed, and the number of compatible implant construct combinations was calculated.Aims
Methods
The goal of the current systematic review was to assess the impact of implant placement accuracy on outcomes following total knee arthroplasty (TKA). A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the Ovid Medline, Embase, Cochrane Central, and Web of Science databases in order to assess the impact of the patient-reported outcomes measures (PROMs) and implant placement accuracy on outcomes following TKA. Studies assessing the impact of implant alignment, rotation, size, overhang, or condylar offset were included. Study quality was assessed, evidence was graded (one-star: no evidence, two-star: limited evidence, three-star: moderate evidence, four-star: strong evidence), and recommendations were made based on the available evidence.Aims
Methods
Meeting preoperative expectations is known to be of major influence on postoperative satisfaction after total knee arthroplasty (TKA). Improved management of expectation, resulting in more realistic expectations can potentially lead to higher postoperative satisfaction. The objective of this study was to assess the effect of an additional preoperative education module, addressing realistic expectations for long-term functional recovery, on postoperative satisfaction and expectation fulfilment. In total, 204 primary TKA patients with osteoarthritis were enrolled in this randomized controlled trial (RCT). Patients were allocated to either usual preoperative education (control group) or usual education plus an additional module on realistic expectations (intervention group). Primary outcome was being very satisfied (numerical rating scale for satisfaction ≥ 8) with the treatment result at 12 months' follow-up. Other outcomes were change in preoperative expectations and postoperative expectation fulfilment.Aims
Methods
Osteonecrosis (ON) can cause considerable morbidity in young people who undergo treatment for acute lymphoblastic leukaemia (ALL). The aims of this study were to determine the operations undertaken for ON in this population in the UK, along with the timing of these operations and any sequential procedures that are used in different joints. We also explored the outcomes of those patients treated by core decompression (CD), and compared this with conservative management, in both the pre- or post-collapse stages of ON. UK treatment centres were contacted to obtain details regarding surgical interventions and long-term outcomes for patients who were treated for ALL and who developed ON in UKALL 2003 (the national leukaemia study which recruited patients aged 1 to 24 years at diagnosis of ALL between 2003 and 2011). Imaging of patients with ON affecting the femoral head was requested and was used to score all lesions, with subsequent imaging used to determine the final grade. Kaplan-Meier failure time plots were used to compare the use of CD with non surgical management.Aims
Methods
The objectives of this study were to compare postoperative pain, analgesia requirements, inpatient functional rehabilitation, time to hospital discharge, and complications in patients undergoing conventional jig-based unicompartmental knee arthroplasty (UKA) This prospective cohort study included 146 patients with symptomatic medial compartment knee osteoarthritis undergoing primary UKA performed by a single surgeon. This included 73 consecutive patients undergoing conventional jig-based mobile bearing UKA, followed by 73 consecutive patients receiving robotic-arm assisted fixed bearing UKA. All surgical procedures were performed using the standard medial parapatellar approach for UKA, and all patients underwent the same postoperative rehabilitation programme. Postoperative pain scores on the numerical rating scale and opiate analgesia consumption were recorded until discharge. Time to attainment of predefined functional rehabilitation outcomes, hospital discharge, and postoperative complications were recorded by independent observers.Aims
Patients and Methods
The primary aim of the study was to compare the knee-specific functional outcome of robotic unicompartmental knee arthroplasty (rUKA) with manual total knee arthroplasty (mTKA) for the management of isolated medial compartment osteoarthritis. Secondary aims were to compare length of hospital stay, general health improvement, and satisfaction between rUKA and mTKA. A powered (1:3 ratio) cohort study was performed. A total of 30 patients undergoing rUKA were propensity score matched to 90 patients undergoing mTKA for isolated medial compartment arthritis. Patients were matched for age, sex, body mass index (BMI), and preoperative function. The Oxford Knee Score (OKS) and EuroQol five-dimension questionnaire (EQ-5D) were collected preoperatively and six months postoperatively. The Forgotten Joint Score (FJS) and patient satisfaction were collected six months postoperatively. Length of hospital stay was also recorded.Aims
Methods
Antibiotic-loaded bone cements (ALBCs) may offer early protection against the formation of bacterial biofilm after joint arthroplasty. Use in hip arthroplasty is widely accepted, but there is a lack of evidence in total knee arthroplasty (TKA). The objective of this study was to evaluate the use of ALBC in a large population of TKA patients. Data from the National Joint Registry (NJR) of England and Wales were obtained for all primary cemented TKAs between March 2003 and July 2016. Patient, implant, and surgical variables were analyzed. Cox proportional hazards models were used to assess the influence of ALBC on risk of revision. Body mass index (BMI) data were available in a subset of patients.Aims
Materials and Methods
Opening wedge high tibial osteotomy (HTO) is an established surgical procedure for the treatment of early-stage knee arthritis. Other than infection, the majority of complications are related to mechanical factors – in particular, stimulation of healing at the osteotomy site. This study used finite element (FE) analysis to investigate the effect of plate design and bridging span on interfragmentary movement (IFM) and the influence of fracture healing on plate stress and potential failure. A 10° opening wedge HTO was created in a composite tibia. Imaging and strain gauge data were used to create and validate FE models. Models of an intact tibia and a tibia implanted with a custom HTO plate using two different bridging spans were validated against experimental data. Physiological muscle forces and different stages of osteotomy gap healing simulating up to six weeks postoperatively were then incorporated. Predictions of plate stress and IFM for the custom plate were compared against predictions for an industry standard plate (TomoFix).Objectives
Materials and Methods
Little is known about the relative outcomes of revision of unicompartmental
knee arthroplasty (UKA) and high tibial osteotomy (HTO) to total
knee arthroplasty (TKA). The aim of this study is to compare the
outcomes of revision surgery for the two procedures in terms of
complications, re-revision and patient-reported outcome measures (PROMs)
at a minimum of two years follow-up. This study was a retrospective review of data from an institutional
arthroplasty registry for cases performed between 2001 and 2014.
A total of 292 patients were identified, of which 217 had a revision
of HTO to TKA, and 75 had revision of UKA to TKA. While mean follow-up
was longer for the HTO group compared with the UKA group, patient
demographics (age, body mass index and Charlson co-morbidity index)
and PROMs (Short Form-36, Oxford Knee Score, Knee Society Score,
both objective and functional) were similar in the two groups prior
to revision surgery. Outcomes included the rate of complications
and
re-operation, PROMS and patient-reported satisfaction at six months
and two years post-operatively. We also compared the duration of
surgery and the need for revision implants in the two groups. Aims
Patients and Methods
This study reports on a secondary exploratory analysis of the early clinical outcomes of a randomised clinical trial comparing robotic arm-assisted unicompartmental knee arthroplasty (UKA) for medial compartment osteoarthritis of the knee with manual UKA performed using traditional surgical jigs. This follows reporting of the primary outcomes of implant accuracy and gait analysis that showed significant advantages in the robotic arm-assisted group. A total of 139 patients were recruited from a single centre. Patients were randomised to receive either a manual UKA implanted with the aid of traditional surgical jigs, or a UKA implanted with the aid of a tactile guided robotic arm-assisted system. Outcome measures included the American Knee Society Score (AKSS), Oxford Knee Score (OKS), Forgotten Joint Score, Hospital Anxiety Depression Scale, University of California at Los Angeles (UCLA) activity scale, Short Form-12, Pain Catastrophising Scale, somatic disease (Primary Care Evaluation of Mental Disorders Score), Pain visual analogue scale, analgesic use, patient satisfaction, complications relating to surgery, 90-day pain diaries and the requirement for revision surgery.Objectives
Methods
Progressive degenerative changes in the medial
compartment of the knee following lateral unicompartmental arthroplasty
(UKA) remains a leading indication for revision surgery. The purpose
of this study is to evaluate changes in the congruence and joint
space width (JSW) of the medial compartment following lateral UKA.
The congruence of the medial compartment of 53 knees (24 men, 23
women, mean age 13.1 years; Our data suggest that a well conducted lateral UKA may improve
the congruence and normalise the JSW of the medial compartment,
potentially preventing progression of degenerative change. Cite this article:
Unicompartmental knee arthroplasty (UKA) has
advantages over total knee arthroplasty but national joint registries report
a significantly higher revision rate for UKA. As a result, most
surgeons are highly selective, offering UKA only to a small proportion
(up to 5%) of patients requiring arthroplasty of the knee, and consequently
performing few each year. However, surgeons with large UKA practices
have the lowest rates of revision. The overall size of the practice
is often beyond the surgeon’s control, therefore case volume may
only be increased by broadening the indications for surgery, and
offering UKA to a greater proportion of patients requiring arthroplasty
of the knee. The aim of this study was to determine the optimal UKA usage
(defined as the percentage of knee arthroplasty practice comprised
by UKA) to minimise the rate of revision in a sample of 41 986 records
from the for National Joint Registry for England and Wales (NJR). UKA usage has a complex, non-linear relationship with the rate
of revision. Acceptable results are achieved with the use of 20%
or more. Optimal results are achieved with usage between 40% and
60%. Surgeons with the lowest usage (up to 5%) have the highest
rates of revision. With optimal usage, using the most commonly used
implant, five-year survival is 96% (95% confidence interval (CI)
94.9 to 96.0), compared with 90% (95% CI 88.4 to 91.6) with low
usage (5%) previously considered ideal. The rate of revision of UKA is highest with low usage, implying
the use of narrow, and perhaps inappropriate, indications. The widespread
use of broad indications, using appropriate implants, would give
patients the advantages of UKA, without the high rate of revision. Cite this article:
We retrospectively studied the major complications occurring after one- and two-stage bilateral unicompartmental knee replacements (UKR). Between 1999 and 2008, 911 patients underwent 1150 UKRs through a minimally invasive approach in our unit. Of these, 159 patients (318 UKRs) had one-stage and 80 patients (160 UKRs) had two-stage bilateral UKRs. The bilateral UKR groups were comparable in age and American Society of Anaesthesiology grade, but more women were in the two-stage group (p = 0.019). Mechanical thromboprophylaxis was used in all cases. Major complications were recorded as death, pulmonary embolus, proximal deep-vein thrombosis and adverse cardiac events within 30 days of surgery. No statistical differences between the groups were found regarding the operating surgeon, the tourniquet time or minor complications except for distal deep-vein thrombosis. The anaesthetic times were longer for the two-stage group (p = 0.0001). Major complications were seen in 13 patients (8.2%) with one-stage operations but none were encountered in the two-stage group (p = 0.005). Distal deep-vein thrombosis was more frequent in the two-stage group (p = 0.036). Because of the significantly higher risk of major complications associated with one-stage bilateral UKR we advocate caution before undertaking such a procedure.
We compared the length of hospitalisation, rate
of infection, dislocation of the hip and revision, and mortality following
primary hip and knee arthroplasty for osteoarthritis in patients
with Alzheimer’s disease (n = 1064) and a matched control group
(n = 3192). The data were collected from nationwide Finnish health
registers. Patients with Alzheimer’s disease had a longer peri-operative
hospitalisation (median 13 days Cite this article:
We evaluated the duration of hospitalisation,
occurrence of infections, hip dislocations, revisions, and mortality following
primary hip and knee replacement in 857 patients with Parkinson’s
disease and compared them with 2571 matched control patients. The
data were collected from comprehensive nationwide Finnish health
registers. The mean follow-up was six years (1 to 13). The patients
with Parkinson’s disease had a longer mean length of stay (21 days
[1 to 365] Cite this article:
We present detailed information about early morbidity
after aseptic revision knee replacement from a nationwide study.
All aseptic revision knee replacements undertaken between 1st October
2009 and 30th September 2011 were analysed using the Danish National
Patient Registry with additional information from the Danish Knee
Arthroplasty Registry. The 1218 revisions involving 1165 patients
were subdivided into total revisions, large partial revisions, partial
revisions and revisions of unicondylar replacements (UKR revisions).
The mean age was 65.0 years (27 to 94) and the median length of
hospital stay was four days (interquartile range: 3 to 5), with
a 90 days re-admission rate of 9.9%,
re-operation rate of 3.5% and mortality rate of 0.2%. The age ranges
of 51 to 55 years (p = 0.018), 76 to 80 years (p <
0.001) and ≥ 81
years (p <
0.001) were related to an increased risk of re-admission.
The age ranges of 76 to 80 years (p = 0.018) and the large partial
revision subgroup (p = 0.073) were related to an increased risk
of re-operation. The ages from 76 to 80 years (p <
0.001), age ≥ 81
years (p <
0.001) and surgical time >
120 min (p <
0.001)
were related to increased length of hospital stay, whereas the use
of a tourniquet (p = 0.008) and surgery in a low volume centre (p
= 0.013) were related to shorter length of stay. In conclusion, we found a similar incidence of early post-operative
morbidity after aseptic knee revisions as has been reported after
primary procedures. This suggests that a length of hospital stay ≤ four
days and discharge home at that time is safe following aseptic knee
revision surgery in Denmark. Cite this article:
Focal femoral inlay resurfacing has been developed
for the treatment of full-thickness chondral defects of the knee. This
technique involves implanting a defect-sized metallic or ceramic
cap that is anchored to the subchondral bone through a screw or
pin. The use of these experimental caps has been advocated in middle-aged
patients who have failed non-operative methods or biological repair
techniques and are deemed unsuitable for conventional arthroplasty
because of their age. This paper outlines the implant design, surgical
technique and biomechanical principles underlying their use. Outcomes
following implantation in both animal and human studies are also reviewed. Cite this article:
The outcome of high tibial osteotomy (HTO) deteriorates
with time, and additional procedures may be required. The aim of
this study was to compare the clinical and radiological outcomes
between unicompartmental knee replacement (UKR) and total knee replacement
(TKR) after HTO as well as after primary UKR. A total of 63 patients (63
knees) were studied retrospectively and divided into three groups:
UKR after HTO (group A; n = 22), TKR after HTO (group B; n = 18)
and primary UKR (group C; n = 22). The Oxford knee score (OKS),
Knee Society score (KSS), hip–knee–ankle angles, mechanical axis
and patellar height were evaluated pre- and post-operatively. At
a mean of 64 months (19 to 180) post-operatively the mean OKS was
43.8 (33 to 49), 43.3 (30 to 48) and 42.5 (29 to 48) for groups
A, B and C, respectively (p = 0.73). The mean KSS knee score was
88.8 (54 to 100), 88.11 (51 to 100) and 85.3 (45 to 100) for groups
A, B and C, respectively (p = 0.65), and the mean KSS function score
was 85.0 (50 to 100) in group A, 85.8 (20 to 100) in group B and
79.3 (50 to 100) in group C (p = 0.48). Radiologically the results
were comparable for all groups except for patellar height, with
a higher incidence of patella infra following a previous HTO (p
= 0.02). Cite this article:
As many as 25% to 40% of unicompartmental knee
replacement (UKR) revisions are performed for pain, a possible cause
of which is proximal tibial strain. The aim of this study was to
examine the effect of UKR implant design and material on cortical
and cancellous proximal tibial strain in a synthetic bone model.
Composite Sawbone tibiae were implanted with cemented UKR components
of different designs, either all-polyethylene or metal-backed. The tibiae
were subsequently loaded in 500 N increments to 2500 N, unloading
between increments. Cortical surface strain was measured using a
digital image correlation technique. Cancellous damage was measured
using acoustic emission, an engineering technique that detects sonic
waves (‘hits’) produced when damage occurs in material. Anteromedial cortical surface strain showed significant differences
between implants at 1500 N and 2500 N in the proximal 10 mm only
(p <
0.001), with relative strain shielding in metal-backed implants.
Acoustic emission showed significant differences in cancellous bone
damage between implants at all loads (p = 0.001). All-polyethylene implants
displayed 16.6 times the total number of cumulative acoustic emission
hits as controls. All-polyethylene implants also displayed more
hits than controls at all loads (p <
0.001), more than metal-backed
implants at loads ≥ 1500 N (p <
0.001), and greater acoustic
emission activity on unloading than controls (p = 0.01), reflecting
a lack of implant stiffness. All-polyethylene implants were associated
with a significant increase in damage at the microscopic level compared
with metal-backed implants, even at low loads. All-polyethylene
implants should be used with caution in patients who are likely
to impose large loads across their knee joint. Cite this article:
The results of hip and knee replacement surgery
are generally regarded as positive for patients. Nonetheless, they are
both major operations and have recognised complications. We present
a review of relevant claims made to the National Health Service
Litigation Authority. Between 1995 and 2010 there were 1004 claims
to a value of £41.5 million following hip replacement surgery and
523 claims to a value of £21 million for knee replacement. The most common
complaint after hip surgery was related to residual neurological
deficit, whereas after knee replacement it was related to infection.
Vascular complications resulted in the highest costs per case in
each group. Although there has been a large increase in the number of operations
performed, there has not been a corresponding relative increase
in litigation. The reasons for litigation have remained largely
unchanged over time after hip replacement. In the case of knee replacement,
although there has been a reduction in claims for infection, there
has been an increase in claims for technical errors. There has also
been a rise in claims for non-specified dissatisfaction. This information
is of value to surgeons and can be used to minimise the potential
mismatch between patient expectation, informed consent and outcome. Cite this article:
Autologous chondrocyte implantation (ACI) and
mosaicplasty are methods of treating symptomatic articular cartilage
defects in the knee. This study represents the first long-term randomised
comparison of the two techniques in 100 patients at a minimum follow-up
of ten years. The mean age of the patients at the time of surgery was
31.3 years (16 to 49); the mean duration of symptoms pre-operatively
was 7.2 years (9 months to 20 years). The lesions were large with
the mean size for the ACI group being 440.9 mm2 (100
to 1050) and the mosaicplasty group being 399.6 mm2 (100
to 2000). Patients had a mean of 1.5 previous operations (0 to 4)
to the articular cartilage defect. Patients were assessed using
the modified Cincinnati knee score and the Stanmore-Bentley Functional Rating
system. The number of patients whose repair had failed at ten years
was ten of 58 (17%) in the ACI group and 23 of 42 (55%) in the mosaicplasty
group (p <
0.001). The functional outcome of those patients with a surviving graft
was significantly better in patients who underwent ACI compared
with mosaicplasty (p = 0.02).
The efficacy of circumpatellar electrocautery in reducing the incidence of post-operative anterior knee pain is unknown. We conducted a single-centre, outcome-assessor and patient-blinded, parallel-group, randomised, controlled trial to compare circumpatellar electrocautery with no electrocautery in total knee replacement in the absence of patellar resurfacing. Patients requiring knee replacement for primary osteoarthritis were randomly assigned circumpatellar electrocautery (intervention group) or no electrocautery (control group). The primary outcome measure was the incidence of anterior knee pain. A secondary measure was the standardised clinical and patient-reported outcomes determined by the American Knee Society scores and the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index. A total of 131 knees received circumpatellar electrocautery and 131 had no electrocautery. The overall incidence of anterior knee pain at follow-up at one year was 26% (20% to 31%), with 19% (12% to 26%) in the intervention group and 32% (24% to 40%) in the control group (p = 0.02). The relative risk reduction from electrocautery was 40% (9% to 61%) and the number needed to treat was 7.7 (4.3 to 41.4). The intervention group had a better mean total WOMAC score at follow-up at one year compared with the control group (16.3 (0 to 77.7) Our study suggests that in the absence of patellar resurfacing electrocautery around the margin of the patella improves the outcome of total knee replacement.
We report the clinical and radiological results of a two- to three-year prospective randomised study which was designed to compare a minimally-invasive technique with a standard technique in total knee replacement and was undertaken between January 2004 and May 2007. The mini-midvastus approach was used on 50 patients (group A) and a standard approach on 50 patients (group B). The mean follow-up in both groups was 23 months (24 to 35). The functional outcome was better in group A up to nine months after operation, as shown by statistically significant differences in the mean function score, mean total score and the mean Oxford knee score (all, p = 0.05). Patients in group A had statistically significant greater early flexion (p = 0.04) and reached their greatest mean knee flexion of 126.5° (95° to 135°) 21 days after operation. However, at final follow-up there was no significant difference in the mean maximum flexion between the groups (p = 0.08). Technical errors were identified in six patients from group A (12%) on radiological evaluation. Based on these results, the authors currently use minimally-invasive techniques in total knee replacement in selected cases only.
We have examined the differences in clinical outcome of total knee replacement (TKR) with and without patellar resurfacing in a prospective, randomised study of 181 osteoarthritic knees in 142 patients using the Profix total knee system which has a femoral component with features considered to be anatomical and a domed patellar implant. The procedures were carried out between February 1998 and November 2002. A total of 159 TKRs in 142 patients were available for review at a mean of four years (3 to 7). The patients and the clinical evaluator were blinded in this prospective study. Evaluation was undertaken annually by an independent observer using the knee pain scale and the Knee Society clinical rating system. Specific evaluation of anterior knee pain, stair-climbing and rising from a seated to a standing position was also undertaken. No benefit was shown of TKR with patellar resurfacing over that without resurfacing with respect to any of the measured outcomes. In 22 of 73 knees (30.1%) with and 18 of 86 knees (20.9%) without patellar resurfacing there was some degree of anterior knee pain (p = 0.183). No revisions related to the patellofemoral joint were performed in either group. Only one TKR in each group underwent a re-operation related to the patellofemoral joint. A significant association between knee flexion contracture and anterior knee pain was observed in those knees with patellar resurfacing (p = 0.006).