During total knee replacement (TKR), surgeons can choose whether or not to resurface the patella, with advantages and disadvantages of each approach. Recently, the National Institute for Health and Care Excellence (NICE) recommended always resurfacing the patella, rather than never doing so. NICE found insufficient evidence on selective resurfacing (surgeon’s decision based on intraoperative findings and symptoms) to make recommendations. If effective, selective resurfacing could result in optimal individualized patient care. This protocol describes a randomized controlled trial to evaluate the clinical and cost-effectiveness of primary TKR with always patellar resurfacing compared to selective patellar resurfacing. The PAtellar Resurfacing Trial (PART) is a patient- and assessor-blinded multicentre, pragmatic parallel two-arm randomized superiority trial of adults undergoing elective primary TKR for primary osteoarthritis at NHS hospitals in England, with an embedded internal pilot phase (ISRCTN 33276681). Participants will be randomly allocated intraoperatively on a 1:1 basis (stratified by centre and implant type (cruciate-retaining vs cruciate-sacrificing)) to always resurface or selectively resurface the patella, once the surgeon has confirmed sufficient patellar thickness for resurfacing and that constrained implants are not required. The primary analysis will compare the Oxford Knee Score (OKS) one year after surgery. Secondary outcomes include patient-reported outcome measures at three months, six months, and one year (Knee injury and Osteoarthritis Outcome Score, OKS, EuroQol five-dimension five-level questionnaire, patient satisfaction, postoperative complications, need for further surgery, resource use, and costs). Cost-effectiveness will be measured for the lifetime of the patient. Overall, 530 patients will be recruited to obtain 90% power to detect a four-point difference in OKS between the groups one year after surgery, assuming up to 40% resurfacing in the selective group.Aims
Methods
While mechanical alignment (MA) is the traditional technique in total knee arthroplasty (TKA), its potential for altering constitutional alignment remains poorly understood. This study aimed to quantify unintentional changes to constitutional coronal alignment and joint line obliquity (JLO) resulting from MA. A retrospective cohort study was undertaken of 700 primary MA TKAs (643 patients) performed between 2014 and 2017. Lateral distal femoral and medial proximal tibial angles were measured pre- and postoperatively to calculate the arithmetic hip-knee-ankle angle (aHKA), JLO, and Coronal Plane Alignment of the Knee (CPAK) phenotypes. The primary outcome was the magnitude and direction of aHKA, JLO, and CPAK alterations.Aims
Methods
The aim of this study is to evaluate whether acetabular retroversion (AR) represents a structural anatomical abnormality of the pelvis or is a functional phenomenon of pelvic positioning in the sagittal plane, and to what extent the changes that result from patient-specific functional position affect the extent of AR. A comparative radiological study of 19 patients (38 hips) with AR were compared with a control group of 30 asymptomatic patients (60 hips). CT scans were corrected for rotation in the axial and coronal planes, and the sagittal plane was then aligned to the anterior pelvic plane. External rotation of the hemipelvis was assessed using the superior iliac wing and inferior iliac wing angles as well as quadrilateral plate angles, and correlated with cranial and central acetabular version. Sagittal anatomical parameters were also measured and correlated to version measurements. In 12 AR patients (24 hips), the axial measurements were repeated after matching sagittal pelvic rotation with standing and supine anteroposterior radiographs.Aims
Methods
The use of cementless total knee arthroplasty (TKA) components has increased during the past decade. The initial design of cementless metal-backed patellar components had shown high failure rates due to many factors. The aim of this study was to evaluate the clinical results of a second-generation cementless, metal-backed patellar component of a modern design. This was a retrospective review of 707 primary TKAs in 590 patients from a single institution, using a cementless, metal-backed patellar component with a mean follow-up of 6.9 years (2 to 12). A total of 409 TKAs were performed in 338 females and 298 TKAs in 252 males. The mean age of the patients was 63 years (34 to 87) and their mean BMI was 34.3 kg/m2 (18.8 to 64.5). The patients were chosen to undergo a cementless procedure based on age and preoperative radiological and intraoperative bone quality. Outcome was assessed using the Knee Society knee and function scores and range of motion (ROM), complications, and revisions.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
This systematic review and meta-analysis aimed to compare the influence of patellar resurfacing following cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA) on the incidence of anterior knee pain, knee-specific patient-reported outcome measures, complication rates, and reoperation rates. A systematic review of MEDLINE, PubMed, and Google Scholar was performed to identify randomized controlled trials (RCTs) according to search criteria. Search terms used included: arthroplasty, replacement, knee (Mesh), TKA, prosthesis, patella, patellar resurfacing, and patellar retaining. RCTs that compared patellar resurfacing versus unresurfaced in primary TKA were included for further analysis. Studies were evaluated using the Scottish Intercollegiate Guidelines Network assessment tool for quality and minimization of bias. Data were synthesized and meta-analysis performed.Aims
Methods
Insufficient treatment response in rheumatoid arthritis (RA) patients requires novel treatment strategies to halt disease progression. The potential benefit of combination of cytokine-inhibitors in RA is still unclear and needs further investigation. To explore the impact of combined deficiency of two major cytokines, namely interleukin (IL)-1 and IL-6, in this study double deficient mice for IL-1αβ and IL-6 were investigated in different tumour necrosis factor (TNF)-driven inflammatory bone disorders, namely peripheral arthritis and sacroiliitis, as well as systemic bone loss. Disease course, histopathological features of arthritis, and micro-CT (µCT) bone analysis of local and systemic bone loss were assessed in 15-week-old Aims
Methods
The lateral centre-edge angle (LCEA) is a plain radiological measure of superolateral cover of the femoral head. This study aims to establish the correlation between 2D radiological and 3D CT measurements of acetabular morphology, and to describe the relationship between LCEA and femoral head cover (FHC). This retrospective study included 353 periacetabular osteotomies (PAOs) performed between January 2014 and December 2017. Overall, 97 hips in 75 patients had 3D analysis by Clinical Graphics, giving measurements for LCEA, acetabular index (AI), and FHC. Roentgenographical LCEA, AI, posterior wall index (PWI), and anterior wall index (AWI) were measured from supine AP pelvis radiographs. The correlation between CT and roentgenographical measurements was calculated. Sequential multiple linear regression was performed to determine the relationship between roentgenographical measurements and CT FHC.Aims
Methods
The aim of this study was to determine the association between knee alignment and the vertical orientation of the femoral neck in relation to the floor. This could be clinically important because changes of femoral neck orientation might alter chondral joint contact zones and joint reaction forces, potentially inducing problems like pain in pre-existing chondral degeneration. Further, the femoral neck orientation influences the ischiofemoral space and a small ischiofemoral distance can lead to impingement. We hypothesized that a valgus knee alignment is associated with a more vertical orientation of the femoral neck in standing position, compared to a varus knee. We further hypothesized that realignment surgery around the knee alters the vertical orientation of the femoral neck. Long-leg standing radiographs of patients undergoing realignment surgery around the knee were used. The hip-knee-ankle angle (HKA) and the vertical orientation of the femoral neck in relation to the floor were measured, prior to surgery and after osteotomy-site-union. Linear regression was performed to determine the influence of knee alignment on the vertical orientation of the femoral neck.Aims
Methods
Perthes’ disease (PD) often results in femoral head deformity and leg length discrepancy (LLD). Our objective was to analyze femoral morphology in PD patients at skeletal maturity to assess where the LLD originates, and evaluate the effect of contralateral epiphysiodesis for length equalization on proximal and subtrochanteric femoral lengths. All patients treated for PD in our institution between January 2013 and June 2020 were reviewed retrospectively. Patients with unilateral PD, LLD of ≥ 5 mm, and long-leg standing radiographs at skeletal maturity were included. Total leg length, femoral and tibial length, articulotrochanteric distance (ATD), and subtrochanteric femoral length were compared between PD side and the unaffected side. Furthermore, we compared leg length measurements between patients who did and who did not have a contralateral epiphysiodesis.Aims
Methods
Anterior cruciate ligament (ACL) rupture commonly leads to post-traumatic osteoarthritis, regardless of surgical reconstruction. This study uses standing MRI to investigate changes in contact area, contact centroid location, and tibiofemoral alignment between ACL-injured knees and healthy controls, to examine the effect of ACL reconstruction on these parameters. An upright, open MRI was used to directly measure tibiofemoral contact area, centroid location, and alignment in 18 individuals with unilateral ACL rupture within the last five years. Eight participants had been treated nonoperatively and ten had ACL reconstruction performed within one year of injury. All participants were high-functioning and had returned to sport or recreational activities. Healthy contralateral knees served as controls. Participants were imaged in a standing posture with knees fully extended.Aims
Methods
Recent total knee arthroplasty (TKA) designs have featured more anatomical morphologies and shorter tibial keels. However, several reports have raised concerns about the impact of these modifications on implant longevity. The aim of this study was to report the early performance of a modern, cemented TKA design. All patients who received a primary, cemented TKA between 2012 and 2017 with a minimum two-year follow-up were included. The implant investigated features an asymmetrical tibial baseplate and shortened keel. Patient demographic details, Knee Society Scores (KSS), component alignment, and the presence of radiolucent lines at final follow-up were recorded. Kaplan-Meier analyses were performed to estimate survivorship.Aims
Methods
Cementless total knee arthroplasty (TKA) offers the potential for strong biological fixation compared with cemented TKA where fixation is achieved by the mechanical integration of the cement. Few mid-term results are available for newer cementless TKA designs, which have used additive manufacturing (3D printing). The aim of this study was to present mid-term clinical outcomes and implant survivorship of the cementless Stryker Triathlon Tritanium TKA. This was a single institution registry review of prospectively gathered data from 341 cementless Triathlon Tritanium TKAs at four to 6.8 years follow-up. Outcomes were determined by comparing pre- and postoperative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) scores, and pre- and postoperative 12-item Veterans RAND/Short Form Health Survey (VR/SF-12) scores. Aseptic loosening and revision for any reason were the endpoints which were used to determine survivorship at five years.Aims
Methods
Once knee arthritis and deformity have occurred, it is currently not known how to determine a patient’s constitutional (pre-arthritic) limb alignment. The purpose of this study was to describe and validate the arithmetic hip-knee-ankle (aHKA) algorithm as a straightforward method for preoperative planning and intraoperative restoration of the constitutional limb alignment in total knee arthroplasty (TKA). A comparative cross-sectional, radiological study was undertaken of 500 normal knees and 500 arthritic knees undergoing TKA. By definition, the aHKA algorithm subtracts the lateral distal femoral angle (LDFA) from the medial proximal tibial angle (MPTA). The mechanical HKA (mHKA) of the normal group was compared to the mHKA of the arthritic group to examine the difference, specifically related to deformity in the latter. The mHKA and aHKA were then compared in the normal group to assess for differences related to joint line convergence. Lastly, the aHKA of both the normal and arthritic groups were compared to test the hypothesis that the aHKA can estimate the constitutional alignment of the limb by sharing a similar centrality and distribution with the normal population.Aims
Methods
Eight-plates are used to correct varus-valgus deformity (VVD) or limb-length discrepancy (LLD) in children and adolescents. It was reported that these implants might create a bony deformity within the knee joint by change of the roof angle (RA) after epiphysiodesis of the proximal tibia following a radiological assessment limited to anteroposterior (AP) radiographs. The aim of this study was to analyze the RA, complemented with lateral knee radiographs, with focus on the tibial slope (TS) and the degree of deformity correction. A retrospective, single-centre study was conducted. The treatment group (n = 64 knees in 44 patients) was subclassified according to the implant location in two groups: 1) medial hemiepiphysiodesis; and 2) lateral hemiepiphysiodesis. A third control group consisted of 25 untreated knees. The limb axes and RA were measured on long standing AP leg radiographs. Lateral radiographs of 40 knees were available for TS analysis. The mean age of the patients was 10.6 years (4 to 15) in the treatment group and 8.4 years (4 to 14) in the control group. Implants were removed after a mean 1.2 years (0.5 to 3).Aims
Methods
Although bone cement is the primary mode of fixation in total knee arthroplasty (TKA), cementless fixation is gaining interest as it has the potential of achieving lasting biological fixation. By 3D printing an implant, highly porous structures can be manufactured, promoting osseointegration into the implant to prevent aseptic loosening. This study compares the migration of cementless, 3D-printed TKA to cemented TKA of a similar design up to two years of follow-up using radiostereometric analysis (RSA) known for its ability to predict aseptic loosening. A total of 72 patients were randomized to either cementless 3D-printed or a cemented cruciate retaining TKA. RSA and clinical scores were evaluated at baseline and postoperatively at three, 12, and 24 months. A mixed model was used to analyze the repeated measurements.Aims
Methods
Though the pathogenesis of Legg-Calve-Perthes disease (LCPD) is unknown, repetitive microtrauma resulting in deformity has been postulated. The purpose of this study is to trial a novel upright MRI scanner, to determine whether any deformation occurs in femoral heads affected by LCPD with weightbearing. Children affected by LCPD were recruited for analysis. Children received both standing weightbearing and supine scans in the MROpen upright MRI scanner, for coronal T1 GFE sequences, both hips in field of view. Parameters of femoral head height, width, and lateral extrusion of affected and unaffected hips were assessed by two independent raters, repeated at a one month interval. Inter- and intraclass correlation coefficients were determined. Standing and supine measurements were compared for each femoral head.Aims
Methods
An algorithm to determine the constitutional alignment of the lower limb once arthritic deformity has occurred would be of value when undertaking kinematically aligned total knee arthroplasty (TKA). The purpose of this study was to determine if the arithmetic hip-knee-ankle angle (aHKA) algorithm could estimate the constitutional alignment of the lower limb following development of significant arthritis. A matched-pairs radiological study was undertaken comparing the aHKA of an osteoarthritic knee (aHKA-OA) with the mechanical HKA of the contralateral normal knee (mHKA-N). Patients with Grade 3 or 4 Kellgren-Lawrence tibiofemoral osteoarthritis in an arthritic knee undergoing TKA and Grade 0 or 1 osteoarthritis in the contralateral normal knee were included. The aHKA algorithm subtracts the lateral distal femoral angle (LDFA) from the medial proximal tibial angle (MPTA) measured on standing long leg radiographs. The primary outcome was the mean of the paired differences in the aHKA-OA and mHKA-N. Secondary outcomes included comparison of sex-based differences and capacity of the aHKA to determine the constitutional alignment based on degree of deformity.Aims
Methods
A significant percentage of patients remain dissatisfied after total knee arthroplasty (TKA). The aim of this study was to determine whether the sequential addition of accelerometer-based navigation for femoral component preparation and sensor-guided ligament balancing improved complication rates, radiological alignment, or patient-reported outcomes (PROMs) compared with a historical control group using conventional instrumentation. This retrospective cohort study included 371 TKAs performed by a single surgeon sequentially. A historical control group, with the use of intramedullary guides for distal femoral resection and surgeon-guided ligament balancing, was compared with a group using accelerometer-based navigation for distal femoral resection and surgeon-guided balancing (group 1), and one using navigated femoral resection and sensor-guided balancing (group 2). Primary outcome measures were Patient-Reported Outcomes Measurement Information System (PROMIS) and Knee injury and Osteoarthritis Outcome (KOOS) scores measured preoperatively and at six weeks and 12 months postoperatively. The position of the components and the mechanical axis of the limb were measured postoperatively. The postoperative range of motion (ROM), haematocrit change, and complications were also recorded.Aims
Methods
It has been hypothesized that a unicompartmental knee arthroplasty (UKA) is more likely to be revised than a total knee arthroplasty (TKA) because conversion surgery to a primary TKA is a less complicated procedure. The purpose of this study was to determine if there is a lower threshold for revising a UKA compared with TKA based on Oxford Knee Scores (OKSs) and range of movement (ROM) at the time of revision. We retrospectively reviewed 619 aseptic revision cases performed between December 1998 and October 2018. This included 138 UKAs that underwent conversion to TKA and 481 initial TKA revisions. Age, body mass index (BMI), time in situ, OKS, and ROM were available for all patients.Aims
Methods
Enhanced perioperative protocols have significantly improved patient recovery following primary total knee arthroplasty (TKA). Little has been investigated the effectiveness of these protocols for revision TKA (RTKA). We report on a matched group of aseptic revision and primary TKA patients treated with an identical pain and rehabilitation programmes. Overall, 40 aseptic full-component RTKA patients were matched (surgical date, age, sex, and body mass index (BMI)) to a group of primary cemented TKA patients. All RTKAs had new uncemented stemmed femoral and tibial components with metaphyseal sleeves. Both groups were treated with an identical postoperative pain protocol. Patients were followed for at least two years. Knee Society Scores (KSS) at six weeks and at final follow-up were recorded for both groups.Aims
Methods
We report the natural course of Baker’s cysts following total knee arthroplasty (TKA) at short- and mid-term follow-up. In this prospective case series, 105 TKA patients were included. All patients who received surgery had a diagnosis of primary osteoarthritis and had preoperatively presented with a Baker’s cyst. Sonography and MRI were performed to evaluate the existence and the gross size of the cyst before TKA, and sonography was repeated at a mean follow-up time of 1.0 years (0.8 to 1.3; short-term) and 4.9 years (4.0 to 5.6; mid-term) after TKA. Symptoms potentially attributable to the Baker’s cyst were recorded at each assessment.Aims
Methods
The Precice intramedullary limb-lengthening system has demonstrated significant benefits over external fixation lengthening methods, leading to a paradigm shift in limb lengthening. This study compares outcomes following antegrade and retrograde femoral lengthening in both adolescent and adult patients. A retrospective review of prospectively collected data was undertaken of a consecutive series of 107 femoral lengthening operations in 92 patients. In total, 73 antegrade nails and 34 retrograde nails were inserted. Outcome was assessed by the regenerate healing index (HI), hip and knee range of movement (ROM), and the presence of any complications.Aims
Patients and Methods
Our intention was to investigate if the highly porous biological fixation surfaces of a new 3D-printed total knee arthroplasty (TKA) achieved adequate fixation of the tibial and patellar components to the underlying bone. A total of 29 patients undergoing primary TKA consented to participate in this prospective cohort study. All patients received a highly porous tibial baseplate and metal-backed patella. Patient-reported outcomes measures were recorded and implant migration was assessed using radiostereometric analysis.Aims
Patients and Methods
The use of vitamin E-infused highly crosslinked polyethylene (HXLPE) in total knee prostheses is controversial. In this paper we have compared the clinical and radiological results between conventional polyethylene and vitamin E-infused HXLPE inserts in total knee arthroplasty (TKA). The study included 200 knees (175 patients) that underwent TKA using the same total knee prostheses. In all, 100 knees (77 patients) had a vitamin E-infused HXLPE insert (study group) and 100 knees (98 patients) had a conventional polyethylene insert (control group). There were no significant differences in age, sex, diagnosis, preoperative knee range of movement (ROM), and preoperative Knee Society Score (KSS) between the two groups. Clinical and radiological results were evaluated at two years postoperatively.Aims
Patients and Methods
It has been hypothesized that patellofemoral pain, a common knee condition in adolescents and young adults, may be a precursor of degenerative joint changes and may ultimately lead to patellofemoral osteoarthritis. Since both conditions share several mechanical disease characteristics, such as altered contact area between the femur and patella and increased joint stress, we investigated whether these conditions share similar and different shape characteristics of the patella compared with normal controls. This cross-sectional study compared three different study populations: 32 patellofemoral pain subjects (mean age, 32 years (22 to 45); 72% female); 56 isolated radiological patellofemoral osteoarthritis subjects (mean age, 54 years (44 to 58); 89% female); and 80 healthy control subjects (mean age, 52 years (44 to 58); 74% female). Measurements included questionnaires, and lateral and skyline radiographs of the knee. Two separate 30-point 2D statistical shape models of the patella were created from the lateral and skyline radiographs. A general linear model was used to test for differences in standardized shape modes (a specific shape variant of the patella) between patellofemoral osteoarthritis, patellofemoral pain, and controls, using Bonferroni correction and adjustment for body mass index and gender.Objectives
Methods
Guided growth using eight-plates is commonly used for correction
of angular limb deformities in growing children. The principle is
of tethering at the physeal periphery while enabling growth in the
rest of the physis. The method is also applied for epiphysiodesis
to correct limb-length discrepancy (LLD). Concerns have been raised
regarding the potential of this method to create an epiphyseal deformity.
However, this has not been investigated. The purpose of this study
was to detect and quantify the occurrence of deformities in the
proximal tibial epiphysis following treatment with eight-plates. A retrospective study was performed including 42 children at
a mean age of 10.8 years (3.7 to 15.7) undergoing eight-plate insertion
in the proximal tibia for correction of coronal plane deformities
or LLD between 2007 and 2015. A total of 64 plates were inserted;
48 plates (34 patients) were inserted to correct angular deformities
and 16 plates (8 patients) for LLD. Medical records, Picture Archive
and Communication System images, and conventional radiographs were
reviewed. Measurements included interscrew angle, lateral and medial
plateau slope angles measured between the plateau surface and the
line between the ends of the physis, and tibial plateau roof angle defined
as 180° minus the sum of both plateau angles. Measurements were
compared between radiographs performed adjacent to surgery and those
at latest follow-up, and between operated and non-operated plateaus. Statistical
analysis was performed using BMDP Statistical Software.Aims
Patients and Methods
The aim of this study was to evaluate the effects of using a
portable, accelerometer-based surgical navigation system (KneeAlign2)
in total knee arthroplasty (TKA) on the alignment of the femoral
component, and blood loss. A total of 241 consecutive patients with primary osteoarthritis
of the knee were enrolled in this prospective, randomised controlled
study. There were 207 women and 34 men. The mean age of the patients
was 74.0 years (57 to 89). The KneeAlign2 system was used for distal
femoral resection in 121 patients (KA2 group) and a conventional intramedullary
femoral guide was used in 120 patients (IM group).Aims
Patients and Methods
Sustained intra-articular delivery of pharmacological agents is an attractive modality but requires use of a safe carrier that would not induce cartilage damage or fibrosis. Collagen scaffolds are widely available and could be used intra-articularly, but no investigation has looked at the safety of collagen scaffolds within synovial joints. The aim of this study was to determine the safety of collagen scaffold implantation in a validated A total of 96 rabbits were randomly and equally assigned to four different groups: arthrotomy alone; arthrotomy and collagen scaffold placement; contracture surgery; and contracture surgery and collagen scaffold placement. Animals were killed in equal numbers at 72 hours, two weeks, eight weeks, and 24 weeks. Joint contracture was measured, and cartilage and synovial samples underwent histological analysis.Objectives
Materials and Methods
Since redesign of the Oxford phase III mobile-bearing unicompartmental
knee arthroplasty (UKA) femoral component to a twin-peg design,
there has not been a direct comparison to total knee arthroplasty
(TKA). Thus, we explored differences between the two cohorts. A total of 168 patients (201 knees) underwent medial UKA with
the Oxford Partial Knee Twin-Peg. These patients were compared with
a randomly selected group of 177 patients (189 knees) with primary
Vanguard TKA. Patient demographics, Knee Society (KS) scores and
range of movement (ROM) were compared between the two cohorts. Additionally,
revision, re-operation and manipulation under anaesthesia rates
were analysed.Aims
Patients and Methods
We conducted a randomised controlled trial to assess the accuracy
of positioning and alignment of the components in total knee arthroplasty
(TKA), comparing those undertaken using standard intramedullary
cutting jigs and those with patient-specific instruments (PSI). There were 64 TKAs in the standard group and 69 in the PSI group. The post-operative hip-knee-ankle (HKA) angle and positioning
was investigated using CT scans. Deviation of >
3° from the planned
position was regarded as an outlier. The operating time, Oxford
Knee Scores (OKS) and Short Form-12 (SF-12) scores were recorded.Aims
Patients and Methods
As the number of younger and more active patients
treated with total knee arthroplasty (TKA) continues to increase,
consideration of better fixation as a means of improving implant
longevity is required. Cemented TKA remains the reference standard
with the largest body of evidence and the longest follow-up to support
its use. However, cementless TKA, may offer the opportunity of a
more bone-sparing procedure with long lasting biological fixation
to the bone. We undertook a review of the literature examining advances
of cementless TKA and the reported results. Cite this article:
In arthritis of the varus knee, a high tibial
osteotomy (HTO) redistributes load from the diseased medial compartment
to the unaffected lateral compartment. We report the outcome of 36 patients (33 men and three women)
with 42 varus, arthritic knees who underwent HTO and dynamic correction
using a Garches external fixator until they felt that normal alignment
had been restored. The mean age of the patients was 54.11 years
(34 to 68). Normal alignment was achieved at a mean 5.5 weeks (3
to 10) post-operatively. Radiographs, gait analysis and visual analogue
scores for pain were measured pre- and post-operatively, at one
year and at medium-term follow-up (mean six years; 2 to 10). Failure
was defined as conversion to knee arthroplasty. Pre-operative gait analysis divided the 42 knees into two equal
groups with high (17 patients) or low (19 patients) adductor moments.
After correction, a statistically significant (p <
0.001, At final follow-up, after a mean of 15.9 years (12 to 20), there
was a survivorship of 59% (95% CI 59.6 to 68.9) irrespective of
adductor moment group, with a mean time to conversion to knee arthroplasty
of 9.5 years (3 to 18; 95% confidence interval ± 2.5). HTO remains a useful option in the medium-term for the treatment
of medial compartment osteoarthritis of the knee but does not last
in the long-term. Cite this article:
Nail patella syndrome (NPS) is a skeletal dysplasia with patellofemoral
dysfunction as a key symptom. We present the first in-depth radiological
evaluation of the knee in a large series of NPS patients and describe
the typical malformations. Conventional radiological examination of 95 skeletally mature
patients with NPS was performed. Patellar morphology was classified
according to the Wiberg classification as modified by Baumgartl
and Ficat criteria, and trochlear shape was classified according
to the Dejour classification.Aim
Patients and Methods
Pelvic obliquity is a common finding in adolescents
with cerebral palsy, however, there is little agreement on its measurement
or relationship with hip development at different gross motor function
classification system (GMFCS) levels. The purpose of this investigation was to study these issues in
a large, population-based cohort of adolescents with cerebral palsy
at transition into adult services. The cohort were a subset of a three year birth cohort (n = 98,
65M: 33F, with a mean age of 18.8 years (14.8 to 23.63) at their
last radiological review) with the common features of a migration
percentage greater than 30% and a history of adductor release surgery. Different radiological methods of measuring pelvic obliquity
were investigated in 40 patients and the angle between the acetabular
tear drops (ITDL) and the horizontal reference frame of the radiograph
was found to be reliable, with good face validity. This was selected
for further study in all 98 patients. The median pelvic obliquity was 4° (interquartile range 2° to
8°). There was a strong correlation between hip morphology and the
presence of pelvic obliquity (effect of ITDL on Sharpe’s angle in
the higher hip; rho 7.20 (5% confidence interval 5.59 to 8.81, p
<
0.001). This was particularly true in non-ambulant adolescents
(GMFCS IV and V) with severe pelvic obliquity, but was also easily
detectable and clinically relevant in ambulant adolescents with mild
pelvic obliquity. The identification of pelvic obliquity and its management deserves
closer scrutiny in children and adolescents with cerebral palsy. Cite this article:
In 11 paediatric patients (seven girls and four
boys, from 12 to 15 years old) with unilateral obligatory patellar dislocation
and ligamentous laxity vastus medialis advancement, lateral release,
partial patellar ligament transposition and Galeazzi semitendinosus
tenodesis was undertaken to stabilise the patella. The diagnostic criterion
for ligamentous laxity was based on the Beighton scale. Outcomes
were evaluated radiologically and functionally by measurement of
the range of knee movement and isokinetic testing. The evaluation
also included the Lysholm knee scale. Follow-up studies took place
at a mean of 8.1 years (5 to 15) post-operatively. Normal patellar tracking without any recurrence of dislocation
was obtained in ten out of 11 patients. Pain related to vigorous
activity was reported by nine patients. Compared with the opposite
normal side, the isokinetic tests revealed a statistically significant
decrease in the maximal torque values for the affected quadriceps
muscle (p = 0.003 and p = 0.004), but no difference between the
knee flexors (for angular velocities of 60°/s and 180°/s) (p = 0.858
and p = 0.79). The applied surgical technique generally prevents the recurrence
of the disorder in children with habitual patellar dislocation and
ligamentous laxity. Quadriceps muscle weakness can be expected to
occur post-operatively, Cite this article:
A retrospective review was performed of patients
undergoing primary cementless total knee replacement (TKR) using
porous tantalum performed by a group of surgical trainees. Clinical
and radiological follow-up involved 79 females and 26 males encompassing
115 knees. The mean age was 66.9 years (36 to 85). Mean follow-up
was 7 years (2 to 11). Tibial and patellar components were porous
tantalum monoblock implants, and femoral components were posterior
stabilised (PS) in design with cobalt–chromium fibre mesh. Radiological
assessments were made for implant positioning, alignment, radiolucencies,
lysis, and loosening. There was 95.7% survival of implants. There
was no radiological evidence of loosening and no osteolysis found.
No revisions were performed for aseptic loosening. Average tibial
component alignment was 1.4° of varus (4°of valgus to 9° varus),
and 6.2° (3° anterior to 15° posterior) of posterior slope. Mean
femoral component alignment was 6.6° (1° to 11°) of valgus. Mean tibiofemoral
alignment was 5.6° of valgus (7° varus to 16° valgus). Patellar
tilt was a mean of 2.4° lateral (5° medial to 28° lateral). Patient
satisfaction with improvement in pain was 91%. Cementless TKR incorporating
porous tantalum yielded good clinical and radiological outcomes
at a mean of follow-up of seven-years. Cite this article:
The cam-type deformity in femoroacetabular impingement
is a 3D deformity. Single measurements using radiographs, CT or
MRI may not provide a true estimate of the magnitude of the deformity.
We performed an analysis of the size and location of measurements
of the alpha angle (α°) using a CT technique which could be applied
to the 3D reconstructions of the hip. Analysis was undertaken in
42 patients (57 hips; 24 men and 18 women; mean age 38 years (16
to 58)) who had symptoms of femoroacetabular impingement related
to a cam-type abnormality. An α° of >
50° was considered a significant
indicator of cam-type impingement. Measurements of the α° were made
at different points around the femoral head/neck junction at intervals
of 30°: starting at the nine o’clock (posterior), ten, eleven and
twelve o’clock (superior), one, two and ending at three o’clock
(anterior) position. The mean maximum increased α° was 64.6° (50.8° to 86°). The two
o’clock position was the most common point to find an increased α°
(53 hips; 93%), followed by one o’clock (48 hips; 84%). The largest α°
for each hip was found most frequently at the two o’clock position
(46%), followed by the one o’clock position (39%). Generally, raised α angles
extend over three segments of the clock face. Single measurements of the α°, whether pre- or post-operative,
should be viewed with caution as they may not be representative
of the true size of the deformity and not define whether adequate
correction has been achieved following surgery. Cite this article:
Damage to the cartilage of the distal radioulnar
joint frequently leads to pain and limitation of movement, therefore repair
of this joint cartilage would be highly desirable. The purpose of
this study was to investigate the fixation of scaffold in cartilage
defects of this joint as part of matrix-assisted regenerative autologous
cartilage techniques. Two techniques of fixation of collagen scaffolds,
one involving fibrin glue alone and one with fibrin glue and sutures, were
compared in artificially created cartilage defects of the distal
radioulnar joint in a human cadaver. After being subjected to continuous
passive rotation, the methods of fixation were evaluated for cover
of the defect and pull out force. No statistically significant differences were found between the
two techniques for either cover of the defect or integrity of the
scaffold. However, a significantly increased mean pull out force
was found for the combined procedure, 0.665 N (0.150 to 1.160) This suggests that although successful fixation of a collagen
type I/III scaffold in a distal radioulnar joint cartilage defect
is feasible with both forms of fixation, fixation with glue and
sutures is preferable. Cite this article:
The management of failed autologous chondrocyte
implantation (ACI) and matrix-assisted autologous chondrocyte implantation
(MACI) for the treatment of symptomatic osteochondral defects in
the knee represents a major challenge. Patients are young, active
and usually unsuitable for prosthetic replacement. This study reports
the results in patients who underwent revision cartilage transplantation
of their original ACI/MACI graft for clinical or graft-related failure.
We assessed 22 patients (12 men and 10 women) with a mean age of
37.4 years (18 to 48) at a mean of 5.4 years (1.3 to 10.9). The
mean period between primary and revision grafting was 46.1 months
(7 to 89). The mean defect size was 446.6 mm. 2. (150 to
875) and they were located on 11 medial and two lateral femoral condyles,
eight
Structural allografts may be used to manage uncontained
bone defects in revision total knee replacement (TKR). However,
the availability of cadaver grafts is limited in some areas of Asia.
The aim of this study was to evaluate the mid-term outcome of the
use of femoral head allografts for the reconstruction of uncontained
defects in revision TKR, focusing on complications related to the
graft. We retrospectively reviewed 28 patients (30 TKRs) with Anderson
Orthopaedic Research Institute (AORI) type 3 bone defects, who underwent
revision using femoral head allografts and stemmed components. The
mean number of femoral heads used was 1.7 (1 to 3). The allograft–host
junctions were packed with cancellous autograft. At a mean follow-up of 76 months (38 to 136) the mean American
Knee Society knee score improved from 37.2 (17 to 60) pre-operatively
to 90 (83 to 100) (p <
0.001). The mean function score improved
from 26.5 (0 to 50) pre-operatively to 81 (60 to 100) (p <
0.001).
All the grafts healed to the host bone. The mean time to healing
of the graft was 6.6 months
(4 to 16). There have been no complications of collapse of the graft,
nonunion, infection or implant loosening. No revision surgery was
required. The use of femoral head allografts in conjunction with a stemmed
component and autogenous bone graft in revision TKR in patients
with uncontained bone defects resulted in a high rate of healing
of the graft with minimal complications and a satisfactory outcome.
Longer follow-up is needed to observe the evolution of the graft. Cite this article:
Matrix-assisted autologous chondrocyte transplantation (MACT)
has been developed and applied in the clinical practice in the last
decade to overcome most of the disadvantages of the first generation
procedures. The purpose of this systematic review is to document
and analyse the available literature on the results of MACT in the
treatment of chondral and osteochondral lesions of the knee. All studies published in English addressing MACT procedures were
identified, including those that fulfilled the following criteria:
1) level I-IV evidence, 2) measures of functional or clinical outcome,
3) outcome related to cartilage lesions of the knee cartilage.Objectives
Methods
Deformity after slipped upper femoral epiphysis
(SUFE) can cause cam-type femoroacetabular impingement (FAI) and
subsequent osteoarthritis (OA). However, there is little information
regarding the radiological assessment and clinical consequences
at long-term follow-up. We reviewed 36 patients (43 hips) previously
treated by We conclude that persistent deformity with radiological cam FAI
after SUFE is associated with poorer clinical and radiological long-term
outcome. Although the radiological measurements had quite wide limits
of agreement, they are useful for the diagnosis of post-slip deformities
in clinical practice.
Disruption of the extensor mechanism in total
knee arthroplasty may occur by tubercle avulsion, patellar or quadriceps
tendon rupture, or patella fracture, and whether occurring intra-operatively
or post-operatively can be difficult to manage and is associated
with a significant rate of failure and associated complications.
This surgery is frequently performed in compromised tissues, and
repairs must frequently be protected with cerclage wiring and/or
augmentation with local tendon (semi-tendinosis, gracilis) which
may also be used to treat soft-tissue loss in the face of chronic
disruption. Quadriceps rupture may be treated with conservative
therapy if the patient retains active extension. Component loosening
or loss of active extension of 20° or greater are clear indications
for surgical treatment of patellar fracture. Acute patellar tendon
disruption may be treated by primary repair. Chronic extensor failure
is often complicated by tissue loss and retraction can be treated
with medial gastrocnemius flaps, achilles tendon allografts, and
complete extensor mechanism allografts. Attention to fixing the
graft in full extension is mandatory to prevent severe extensor
lag as the graft stretches out over time.
Seven stiff total knee arthroplasties are presented
to illustrate the roles of: 1) manipulation under general anesthesia;
2) multiple concurrent diagnoses in addition to stiffness; 3) extra-articular
pathology; 4) pain as part of the stiffness triad (pain and limits
to flexion or extension); 5) component internal rotation; 6) multifactorial
etiology; and 7) surgical exposure in this challenging clinical
problem.
Numerous complications following total knee replacement (TKR)
relate to the patellofemoral (PF) joint, including pain and patellar
maltracking, yet the options for A total of three knees with end-stage osteoarthritis and three
knees that had undergone TKR at more than one year’s follow-up were
investigated. In each knee, sequential biplane radiological images
were acquired from the sagittal direction (i.e. horizontal X-ray
source and 10° below horizontal) for a sequence of eight flexion
angles. Three-dimensional implant or bone models were matched to
the biplane images to compute the six degrees of freedom of PF tracking
and TF kinematics, and other clinical measures.Objectives
Methods
The October 2012 Knee Roundup. 360. looks at: autologous chondrocytes and chondromalacia
Despite many claims of good wear properties following
total knee replacement (TKR) with an oxidised zirconium (OxZr) femoral
component, there are conflicting clinical results. We hypothesised
that there would be no difference in either the mid-term clinical
and radiological outcomes or the characteristics of the polyethylene
wear particles (weight, size and shape) in patients using an OxZr
or cobalt-chrome (CoCr) femoral component. In all 331 patients underwent
bilateral TKR, receiving an OxZr femoral component in one knee and
a CoCr femoral component in the other. The mean follow-up was 7.5
years (6 to 8). Following aspiration, polyethylene wear particles
were analysed using thermogravimetric methods and scanning electron
microscopy. At the most recent follow-up, the mean Knee Society
score, Western Ontario and McMaster Universities Osteoarthritis
Index score, range of movement and satisfaction score were not significantly
different in the two groups. The mean weight, size, aspect ratio
and roundness of the aspirated wear particles were similar for each
femoral component. Survivorship of the femoral, tibial and patellar
components was 100% in both groups. In the absence of evidence of an advantage in the medium term
we cannot justify the additional expense of an OxZr femoral component.
Obtaining a balanced flexion gap with correct
femoral component rotation is one of the prerequisites for a successful
outcome after total knee replacement (TKR). Different techniques
for achieving this have been described. In this study we prospectively
compared gap-balancing Both groups systematically reproduced a similar external rotation
of the femoral component relative to the surgical transepicondylar
axis: 2.4°
This review considers the surgical treatment
of displaced fractures involving the knee in elderly, osteoporotic patients.
The goals of treatment include pain control, early mobilisation,
avoidance of complications and minimising the need for further surgery.
Open reduction and internal fixation (ORIF) frequently results in
loss of reduction, which can result in post-traumatic arthritis
and the occasional conversion to total knee replacement (TKR). TKR
after failed internal fixation is challenging, with modest functional
outcomes and high complication rates. TKR undertaken as treatment
of the initial fracture has better results to late TKR, but does
not match the outcome of primary TKR without complications. Given
the relatively infrequent need for late TKR following failed fixation,
ORIF is the preferred management for most cases. Early TKR can be
considered for those patients with pre-existing arthritis, bicondylar
femoral fractures, those who would be unable to comply with weight-bearing restrictions,
or where a single definitive procedure is required.
Objectives. To assess the effectiveness of a modified tibial tubercle osteotomy
as a treatment for arthroscopically diagnosed chondromalacia
Peri-prosthetic patellar fracture following resurfacing
as part of total knee replacement (TKR) is an infrequent yet challenging
complication. This case-control study was performed to identify
clinical, radiological and surgical factors that increase the risk
of developing a spontaneous patellar fracture after TKR. Patellar
fractures were identified in 74 patients (88 knees) from a series
of 7866 consecutive TKRs conducted between 1998 and 2009. After excluding
those with a previous history of extensor mechanism realignment
or a clear traumatic event, a metal-backed patella, any uncemented
component or subsequent infection, the remaining 64 fractures were
compared with a matched group of TKRs with an excellent outcome
defined by the Knee Society score. The mean age of patients with
a fracture was 70 years (51 to 81) at the time of TKR. Patellar
fractures were detected at a mean of 13.4 months (2 to 84) after
surgery. The incidence of patellar fracture was found to be strongly
associated with the number of previous knee operations, greater
pre-operative mechanical malalignment, smaller post-operative patellar
tendon length, thinner post-resection patellar thickness, and a
lower post-operative Insall-Salvati ratio. An understanding of the risk factors associated with spontaneous
patellar fracture following TKR provides a valuable insight into
prevention of this challenging complication.
This prospective study compares the outcome of
157 hydroxyapatite (HA)-coated tibial components with 164 cemented
components in the ROCC Rotating Platform total knee replacement
in 291 patients. The mean follow-up was 7.6 years (5.2 to 11). There
were two revisions for loosening: one for an HA-coated and one for
a cemented tibial component. Radiological evaluation demonstrated
no radiolucent lines with the HA-coated femoral components. A total
of three HA-coated tibial components exhibited radiolucent lines
at three months post-operatively and these disappeared after three
further months of protected weight-bearing. With HA-coated components
the operating time was shorter (p <
0.006) and the radiological
assessment of the tibial interface was more stable (p <
0.01).
Using revision for aseptic loosening of the tibial component as
the end point, the survival rates at nine years was identical for
both groups at 99.1%. Our results suggest that HA-coated components perform at least
as well as the same design with cemented components and compare
favourably with those of series describing cemented or porous-coated
knee replacements, suggesting that fixation of both components with
hydroxyapatite is a reliable option in primary total knee replacement.
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).
Matrix-induced autologous chondrocyte implantation
(MACI) is an established technique used to treat osteochondral lesions
in the knee. For larger osteochondral lesions (>
5 cm2)
deeper than approximately 8 mm we have combined the use of two MACI
membranes with impaction grafting of the subchondral bone. We report
our results of 14 patients who underwent the ‘bilayer collagen membrane’
technique (BCMT) with a mean follow-up of 5.2 years (2 to 8). There
were 12 men and two women with a mean age of 23.6 years (16 to 40).
The mean size of the defect was 7.2 cm2 (5.2 to 12 cm2)
and were located on the medial (ten) or lateral (four) femoral condyles.
The mean modified Cincinnati knee score improved from 45.1 (22 to
70) pre-operatively to 82.8 (34 to 98) at the most recent review
(p <
0.05). The visual analogue pain score improved from 7.3
(4 to 10) to 1.7 (0 to 6) (p <
0.05). Twelve patients were considered
to have a good or excellent clinical outcome. One graft failed at
six years. The BCMT resulted in excellent functional results and durable
repair of large and deep osteochondral lesions without a high incidence
of graft-related complications.
Patients with skeletal dysplasia are prone to
developing advanced osteoarthritis of the knee requiring total knee replacement
(TKR) at a younger age than the general population. TKR in this
unique group of patients is a technically demanding procedure owing
to the deformity, flexion contracture, generalised hypotonia and ligamentous
laxity. We retrospectively reviewed the outcome of 11 TKRs performed
in eight patients with skeletal dysplasia at our institution using
the Stanmore Modular Individualised Lower Extremity System (SMILES)
custom-made rotating-hinge TKR. There were three men and five women
with mean age of 57 years (41 to 79). Patients were followed clinically
and radiologically for a mean of seven years (3 to 11.5). The mean
Knee Society clinical and function scores improved from 24 (14 to
36) and 20 (5 to 40) pre-operatively, respectively, to 68 (28 to
80) and 50 (22 to 74), respectively, at final follow-up. Four complications
were recorded, including a patellar fracture following a fall, a
tibial peri-prosthetic fracture, persistent anterior knee pain,
and aseptic loosening of a femoral component requiring revision.
Our results demonstrate that custom primary rotating-hinge TKR in
patients with skeletal dysplasia is effective at relieving pain,
with a satisfactory range of movement and improved function. It compensates
for bony deformity and ligament deficiency and reduces the likelihood
of corrective osteotomy. Patellofemoral joint complications are
frequent and functional outcome is worse than with primary TKR in
the general population.
The purpose of this prospective, randomised study
was to evaluate the clinical and radiological results comparing the
identical cemented or cementless NexGen total knee prostheses implanted
bilaterally in the same patient. Sequential simultaneous bilateral
total knee replacements were performed in 50 patients (100 knees).
There were 39 women and 11 men with a mean age of 58.4 years (51
to 67) who received a cemented prosthesis in one knee and a cementless
prosthesis in the other. The mean follow-up was 13.6 years (13 to
14). At final review, the mean Knee Society scores (96.2 (82 to
100)
Patella subluxation assessed on dynamic MRI has
previously been shown to be associated with anterior knee pain. In
this MRI study of 60 patients we investigated the relationship between
subluxation and multiple bony, cartilaginous and soft-tissue factors
that might predispose to subluxation using discriminant function
analysis. Patella engagement (% of patella cartilage overlapping with trochlea
cartilage) had the strongest relationship with subluxation. Patellae
with >
30% engagement tended not to sublux; those with <
30%
tended to sublux. Other factors that were associated with subluxation
included the tibial tubercle-trochlea notch distance, vastus medialis obliquus
distance from patella, patella alta, and the bony and cartilaginous
sulcus angles in the superior part of the trochlea. No relationship
was found between subluxation and sulcus angles for cartilage and
bone in the middle and lower part of the trochlea, cartilage thicknesses
and Wiberg classification of the patella. This study indicates that patella engagement is a key factor
associated with patellar subluxation. This suggests that in patients
with anterior knee pain with subluxation, resistant to conservative
management, surgery directed towards improving patella engagement
should be considered. A clinical trial is necessary to test this
hypothesis.
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.
Between April 2004 and July 2007, we performed 241 primary total knee replacements in 204 patients using the e.motion posterior cruciate-retaining, multidirectional mobile-bearing prosthesis. Of these, 100 were carried out using an image-free navigation system, and the remaining 141 with the conventional technique. We conducted a retrospective study from the prospectively collected data of these patients to assess the early results of this new mobile-bearing design. At a mean follow-up of 49 months (32 to 71), 18 knees (7.5%) had mechanical complications of which 13 required revision. Three of these had a peri-prosthetic fracture, and were removed from the study. The indication for revision in the remaining ten was loosening of the femoral component in two, tibiofemoral dislocation in three, disassociation of the polyethylene liner in four, and a broken polyethyene liner in one. There were eight further mechanically unstable knees which presented with recurrent disassociation of the polyethylene liner. There was no significant difference in the incidence of mechanical instability between the navigation-assisted procedures (8 of 99, 8.1%) and the conventionally implanted knees (10 of 139, 7.2%). In our view, the relatively high rate of mechanical complications and revision within 30 months precludes the further use of new design of knee replacement.
We present the results of the surgical correction of lower-limb deformities caused by metabolic bone disease. Our series consisted of 17 patients with a diagnosis of hypophosphataemic rickets and two with renal osteodystrophy; their mean age was 25.6 years (14 to 57). In all, 43 lower-limb segments (27 femora and 16 tibiae) were osteotomised and the deformity corrected using a monolateral external fixator. The segment was then stabilised with locked intramedullary nailing. In addition, six femora in three patients were subsequently lengthened by distraction osteogenesis. The mean follow-up was 60 months (18 to 120). The frontal alignment parameters (the mechanical axis deviation, the lateral distal femoral angle and the medial proximal tibial angle) and the sagittal alignment parameters (the posterior distal femoral angle and the posterior proximal tibial angle) improved post-operatively. The external fixator was removed either at the end of surgery or at the end of the lengthening period, allowing for early mobilisation and weight-bearing. We encountered five problems and four obstacles in the programme of treatment. The use of intramedullary nails prevented recurrence of deformity and refracture.
Isolated patellofemoral osteoarthritis can be a disabling disease. When conservative treatment fails, surgical options can be unpredictable and may be considered too aggressive for middle-aged and active people. We analysed the clinical and radiological results of a new coronal osteotomy involving thinning of the patella in a selected group of patients with isolated patellofemoral osteoarthritis. Since 1991, 31 patients (35 knees) have been treated, of whom 34 were available for follow-up at a mean of 9.1 years. The Knee Society Score, the Patellar score and the Short-form-36 questionnaire were used for clinical evaluation. We also examined the radiological features to confirm bone consolidation and assess the progression of osteoarthritis. A significant improvement in the functional scores and radiological parameters was noted. All patients except one were satisfied with the operation. Radiological progression of the patellofemoral osteoarthritis was slowed but radiological femorotibial osteoarthritis progressed in 23 (65%) cases, with a total knee replacement becoming necessary in four cases without technical problems in resurfacing the patella. We compared the results with other forms of surgical treatment reported in the literature. This treatment offers good clinical and radiological results, presenting an alternative method of managing patellofemoral osteoarthritis.
Many radiographic techniques have been described for measuring patellar height. They can be divided into two groups: those that relate the position of the patella to the femur (direct) and those that relate it to the tibia (indirect). This article looks at the methods that have been described, the logic behind their conception and the critical analyses that have been performed to test them.
We undertook a study in which 138 female patients with a mean age of 71.2 years (51 to 82) received a standard NexGen CR-flex prosthesis in one knee and a gender-specific NexGen CR-flex prosthesis in the other. The mean follow-up period was 3.25 years (3.1 to 3.5). The aspect ratios of the standard and gender-specific prostheses were compared with that of the distal femur. The mean post-operative Knee Society knee scores were 94 (70 to 100) and 93 (70 to 100) points and the function scores were 83 (60 to 100) and 84 (60 to 100) points for the standard implants and the gender-specific designs, respectively. The mean post-operative Western Ontario and McMaster Universities score was 26.4 points (0 to 76). Patient satisfaction, the radiological results and the complication rates were similar in the two groups. In those with a standard prosthesis, the femoral component was closely matched in 80 knees (58.0%), overhung in 14 (10.1%) and undercovered the bone in 44 (31.9%). In those with a gender-specific prosthesis, it was closely matched in 15 knees (10.9%) and undercovered the bone in 123 (89.1%). Since we found no significant differences between the two groups with regard to the clinical and radiological results, patient satisfaction or complication rate, the goal of the design of the gender-specific CR-flex prosthesis to improve the outcome was not achieved in our patients.
The management of osteoarthritis of the knee associated with patellar instability secondary to external tibial torsion >
45° is challenging. Patellofemoral biomechanics in these patients cannot be achieved by intra-articular correction using standard techniques of total knee replacement. We reviewed seven patients (eight knees) with recurrent patellar dislocation and one with bilateral irreducible lateral dislocation who had undergone simultaneous total knee replacement and internal tibial derotational osteotomy. All had osteoarthritis and severe external tibial torsion. The mean follow-up was for 47.2 months (24 to 120). The mean objective and functional Knee Society scores improved significantly (p = 0.0001) from 29.7 and 41.5 pre-operatively to 71.4 and 73.5 post-operatively, respectively. In all patients the osteotomies healed and patellar stability was restored. Excessive external tibial torsion should be identified and corrected in patients with osteoarthritis and patellar instability. Simultaneous internal rotation osteotomy of the tibia and total knee replacement is a technically demanding but effective treatment for such patients.
Autologous chondrocyte implantation is an option in the treatment of full-thickness chondral or osteochondral injuries which are symptomatic. The goal of surgery and rehabilitation is the replacement of damaged cartilage with hyaline or hyaline-like cartilage, producing improved levels of function and preventing early osteoarthritis. The intermediate results have been promising in terms of functional and clinical improvement. Our aim was to explore the hypothesis that the histological quality of the repair tissue formed after autologous chondrocyte implantation improved with increasing time after implantation. In all, 248 patients who had undergone autologous chondrocyte implantation had biopsies taken of the repair tissue which then underwent histological grading. Statistical analysis suggested that with doubling of the time after implantation the likelihood of a favourable histological outcome was increased by more than fourfold (p <
0.001).
This study examined the relationship between the cross-over sign and the true three-dimensional anatomical version of the acetabulum. We also investigated whether in true retroversion there is excessive femoral head cover anteriorly. Radiographs of 64 hips in patients being investigated for symptoms of femoro-acetabular impingement were analysed and the presence of a cross-over sign was documented. CT scans of the same hips were analysed to determine anatomical version and femoral head cover in relation to the anterior pelvic plane after correcting for pelvic tilt. The sensitivity and specificity of the cross-over sign were 92% and 55%, respectively for identifying true acetabular retroversion. There was no significant difference in total cover between normal and retroverted cases. Anterior and posterior cover were, however, significantly different (p <
0.001 and 0.002). The cross-over sign was found to be sensitive but not specific. The results for femoral head cover suggest that retroversion is characterised by posterior deficiency but increased cover anteriorly.
Chondral damage to the knee is common and, if left untreated, can proceed to degenerative osteoarthritis. In symptomatic patients established methods of management rely on the formation of fibrocartilage which has poor resistance to shear forces. The formation of hyaline or hyaline-like cartilage may be induced by implanting autologous, cultured chondrocytes into the chondral or osteochondral defect. Autologous chondrocyte implantation may be used for full-thickness chondral or osteochondral injuries which are painful and debilitating with the aim of replacing damaged cartilage with hyaline or hyaline-like cartilage, leading to improved function. The intermediate and long-term functional and clinical results are promising. We provide a review of autologous chondrocyte implantation and describe our experience with the technique at our institution with a mean follow-up of 32 months (1 to 9 years). The procedure is shown to offer statistically significant improvement with advantages over other methods of management of chondral defects.
The long-term success of total knee replacement is multifactorial, including factors relating to the patient, the operation and the implant. The purpose of this study was to examine the 20-year survival of the cemented Anatomical Graduated Component (AGC) total knee replacement. Between 1983 and 2004, 7760 of these were carried out at our institution. Of these, 6726 knees which received the non-modular metal-backed tibial component with compression-moulded polyethylene and had a minimum two-year follow-up were available for study. In all, 36 knees were followed over 20 years with a survival of the tibial and femoral components together of 97.8% (95% confidence interval (CI) 0.9851 to 0.9677), with no implants being revised for polyethylene wear or osteolysis. Age >
70 was associated with increased survival (99.6%, 95% CI 99.0 to 99.8) (p <
0.0001) but pre-operative valgus alignment reduced survival (95.1%, 95% CI 90.0 to 97.6) (p = 0.0056). Age <
55 (p = 0.129), pre-operative varus alignment (p = 0.707), osteonecrosis (p = 0.06), rheumatoid arthritis (p = 0.247), and gender (p = 0.666) were not statistically associated with failure. We attribute the success of the AGC implant to its relatively unconstrained articular geometry and the durability of a non-modular metal-backed tibial component with compression moulded polyethylene.
The purpose of this study was to test the hypothesis that patella alta leads to a less favourable situation in terms of patellofemoral contact force, contact area and contact pressure than the normal patellar position, and thereby gives rise to anterior knee pain. A dynamic knee simulator system based on the Oxford rig and allowing six degrees of freedom was adapted in order to simulate and record the dynamic loads during a knee squat from 30° to 120° flexion under physiological conditions. Five different configurations were studied, with variable predetermined patellar heights. The patellofemoral contact force increased with increasing knee flexion until contact occurred between the quadriceps tendon and the femoral trochlea, inducing load sharing. Patella alta caused a delay of this contact until deeper flexion. As a consequence, the maximal patellofemoral contact force and contact pressure increased significantly with increasing patellar height (p <
0.01). Patella alta was associated with the highest maximal patellofemoral contact force and contact pressure. When averaged across all flexion angles, a normal patellar position was associated with the lowest contact pressures. Our results indicate that there is a biomechanical reason for anterior knee pain in patients with patella alta.
We present a new CT-based method which measures cover of the femoral head in both normal and dysplastic hips and allows assessment of acetabular inclination and anteversion. A clear topographical image of the head with its covered area is generated. We studied 36 normal and 39 dysplastic hips. In the normal hips the mean cover was 73% (66% to 81%), whereas in the dysplastic group it was 51% (38% to 64%). The significant advantage of this technique is that it allows the measurements to be standardised with reference to a specific anatomical plane. When this is applied to assessing cover in surgery for dysplasia of the hip it gives a clearer understanding of where the corrected hip stands in relation to normal and allows accurate assessment of inclination and anteversion.
After obtaining informed consent, 80 patients were randomised to undergo a navigated or conventional total knee replacement. All received a cemented, unconstrained, cruciate-retaining implant with a rotating platform. Full-length standing and lateral radiographs and CT scans of the hip, knee and ankle joint were carried out five to seven days after operation. No notable differences were found between computer-assisted navigation and conventional implantation techniques as regards the rotational alignment of the femoral or tibial components. Although the deviation from the transepicondylar axis was relatively low, there was a considerable range of deviation for the tibial rotational alignment. There was no statistically significant difference regarding the occurrence pattern of outliers in mechanical malalignment but the number of outliers was reduced in the navigated group.
Objective patellar instability has been correlated with dysplasia of the femoral trochlea. This This study has provided objective biomechanical data to support the use of trochleoplasty in the treatment of patellar instability associated with femoral trochlear dysplasia.
Evaluation of patients with painful total knee replacement requires a thorough clinical examination and relevant investigations in order to reach a diagnosis. Awareness of the common and uncommon problems leading to painful total knee replacement is useful in the diagnostic approach. This review article aims to act as a guide to the evaluation of patients with painful total knee replacement.
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).
We describe our experience with the ‘four-in-one’ procedure for habitual dislocation of the patella in five children (six knees). All the patients presented with severe generalised ligamentous laxity and aplasia of the trochlear groove. All had a lateral release, proximal ‘tube’ realignment of the patella, semitendinosus tenodesis and transfer of the patellar tendon. The mean age at the time of the operation was 6.1 years (4.9 to 6.9), and the patients were followed up for a mean of 54.5 months (31 to 66). The clinical results were evaluated using the Kujala score. There has been no recurrence of dislocation. All the patients have returned to full activities and the parents and children were satisfied with the clinical results. The mean Kujala score was 95.3 (88 to 98). Two patients had marginal skin necrosis which healed after debridement and secondary closure. These early results in this small group have shown that the ‘four-in-one’ procedure is effective in the treatment of obligatory dislocation of the patella in children with severe ligamentous laxity and trochlear aplasia.
The emergence of minimally-invasive total knee replacement (TKR) has led to the refinement of several surgical approaches, including the quadriceps-sparing and sub-vastus. There is some disagreement as to the precise definition of the term ‘minimally-invasive’, especially in regard to the preservation of vastus medialis obliquus (VMO). It is known that the termination of VMO is variable and may make these approaches difficult. We have attempted to assess the factors influencing the insertion of VMO and the impact which they have on the approach for TKR. The MR scans of 198 knees were examined to assess the variation in the insertion of VMO in relation to the patella and the effect of variables such as age, gender and the presence of concurrent osteoarthritis of the knee on the insertion. Our findings showed that both age and the presence of osteoarthritis were contributing factors to changes in the level of insertion of VMO. Therefore, not all capsular incisions which extend proximal to the midpole of the patella will violate the quadriceps tendon.
We have examined the results obtained with 72 NexGen legacy posterior stabilised-flex fixed total knee replacements in 47 patients implanted by a single surgeon between March 2003 and September 2004. Aseptic loosening of the femoral component was found in 27 (38%) of the replacements at a mean follow-up of 32 months (30 to 48) and 15 knees (21%) required revision at a mean of 23 months (11 to 45). We compared the radiologically-loose and revised knees with those which had remained well-fixed to identify the factors which had contributed to this high rate of aseptic loosening. Post-operatively, the mean maximum flexion was 136° (110° to 140°) in the loosened group and 125° (95° to 140°) in the well-fixed group (independent These implants allowed a high degree of flexion, but showed a marked rate of early loosening of the femoral component, which was associated with weight-bearing in maximum flexion.
We carried out three total knee replacements with proximal realignment in two patients with severe osteoarthritis of the knee and congenital dislocation of the patella. During the operation, the femur and the tibia were cut according to the recommendations of the manufacturer of the implant. The femoral component was placed in external rotation and the centre of the tibial component aligned in relation to the tibial tuberosity with regard to rotation and translation. After making the bone cuts, the iliotibial tract was detached from Gerdy’s tubercle, the popliteus tendon divided, and the biceps femoris tendon elongated by Z-plasty. After the trial implants were positioned, a proximal re-alignment procedure was performed. One knee had deep infection. There was one dislocated patella which was repositioned, and walking ability was improved in all knees. We believe that the rotational alignment of a prosthesis is as important as the soft-tissue surgery.
Femoroacetabular cam impingement is thought to be a cause of premature osteoarthritis of the hip. The presence of cam malformation was determined in 2803 standardised anteroposterior (AP) pelvic radiographs from the Copenhagen Osteoarthritis Study by measuring the alpha (α) angle and the triangular index, a new measure of asphericity of the femoral head. In addition, the α-angle and the triangular index were assessed on the AP and lateral hip radiographs of 82 men and 82 women randomly selected from patients scheduled for total hip replacement (THR). The influence of varying femoral rotation on the α angle and the triangular index was also determined in femoral specimens under experimental conditions. From the 2803 radiographs the mean AP α-angle was 55° (30° to 100°) in men and 45° (34° to 108°) in women. Approximately 6% of men and 2% of women had cam malformation. The α-angle and triangular index were highly inter-related. Of those patients scheduled for THR, 36 men (44%) and 28 women (35%) had cam malformation identifiable on the AP radiographs. The triangular index proved to be more reliable in detecting cam malformation when the hip was held in varying degrees of rotation. The combination of the α-angle and the triangular index will allow examination of historical radiographs for epidemiological purposes in following the natural history of the cam deformity.
We compared the results of 146 patients who received an anatomic modular knee fixed-bearing total knee replacement (TKR) in one knee and a low contact stress rotating platform mobile-bearing TKR in the other. There were 138 women and eight men with a mean age of 69.8 years (42 to 80). The mean follow-up was 13.2 years (11.0 to 14.5). The patients were assessed clinically and radiologically using the rating systems of the Hospital for Special Surgery and the Knee Society at three months, six months, one year, and annually thereafter. The assessment scores of both rating systems pre-operatively and at the final review did not show any statistically significant differences between the two designs of implant. In the anatomic modular knee group, one knee was revised because of aseptic loosening of the tibial component and one because of infection. In addition, three knees were revised because of wear of the polyethylene tibial bearing. In the low contact stress group, two knees were revised because of instability requiring exchange of the polyethylene insert and one because of infection. The radiological analysis found no statistical difference in the incidence of radiolucent lines at the final review (Student’s We found no evidence of the superiority of one design over the other at long-term follow-up.
We retrospectively reviewed the operative treatment carried out between 1988 and 1994 of eight patients with habitual patellar dislocation. In four the condition was bilateral. All patients had recurrent dislocation with severe functional disability. The surgical technique involved distal advancement of the patella by complete mobilisation of the patellar tendon, lateral release and advancement of vastus medialis obliquus. The long-term results were assessed radiologically, clinically and functionally using the Lysholm knee score, by an independent observer. The mean age at operation was 10.3 years (7 to 14) with a mean follow-up of 13.5 years (11 to 16). One patient required revision. At the latest follow-up, all
Limited access surgery is thought to reduce post-operative morbidity and provide faster recovery of function. The percutaneous compression plate (PCCP) is a recently introduced device for the fixation of intertrochanteric fractures with minimal exposure. It has several potential mechanical advantages over the conventional compression hip screw (CHS). Our aim in this prospective, randomised, controlled study was to compare the outcome of patients operated on using these two devices. We randomised 104 patients with intertrochanteric fractures (AO/OTA 31.A1–A2) to surgical treatment with either the PCCP or CHS and followed them for one year postoperatively. The mean operating blood loss was 161.0 ml (8 to 450) in the PCCP group and 374.0 ml (11 to 980) in the CHS group (Student’s The PCCP device was associated with reduced intra-operative blood loss, less postoperative pain and a reduced incidence of collapse of the fracture.
We conducted a randomised prospective study to evaluate the clinical and radiological results of a mobile- and fixed-bearing total knee replacement of similar design in 174 patients who had bilateral simultaneous knee replacement. The mean follow-up was for 5.6 years (5.2 to 6.1). The total knee score, pain score, functional score and range of movement were not statistically different (p >
0.05) between the two groups. Osteolysis was not seen in any knee in either group. Two knees (1%) in the mobile-bearing group required revision because of infection; none in the fixed-bearing group needed revision. Excellent results can be achieved with both mobile- and fixed-bearing prostheses of similar design at mid-term follow-up. We could demonstrate no significant clinical advantage for a mobile bearing.
Transtrochanteric curved varus osteotomy was designed to avoid some of the disadvantages of varus wedge osteotomy, such as post-operative leg-length discrepancy. In this retrospective study we investigated the leg-length discrepancy and clinical outcome after transtrochanteric curved varus osteotomy undertaken in patients with osteonecrosis of the femoral head. Between January 1993 and March 2004, this osteotomy was performed in 42 hips of 36 patients with osteonecrosis of the femoral head. There were 15 males and 21 females with a mean age at surgery of 34 years (15 to 68). The mean follow-up was 5.9 years (2.0 to 12.5). The mean pre-operative Harris hip score was 64.0 (43 to 85) points, which improved to a mean of 88.7 (58 to 100) points at final follow-up. The mean varus angulation post-operatively was 25° (12° to 38°) and the post-operative mean leg-length discrepancy was 13 mm (4 to 25). The post-operative leg-length discrepancy showed a strong correlation with varus angulation (Pearson’s correlation coefficient; r = 0.9530, p <
0.0001), which may be useful for predicting the leg-length discrepancy which can occur even after transtrochanteric curved varus osteotomy.
We used three-dimensional movement analysis by computer modelling of knee flexion from 0° to 50° in 14 knees in 12 patients with recurrent patellar dislocation and in 15 knees in ten normal control subjects to compare the The patients had greater values of spin from 20° to 50°, while there were no statistically significant differences in flexion and tilt. The patients also had greater percentage patellar shift from 0° to 50°, percentage tubercle shift at 0° and 10° and patellar inclination from 0° to 50° with a smaller oval-shaped contact area from 20° to 50° moving downwards on the lateral facet. Patellar movement analysis using a three-dimensional computer model is useful to clearly demonstrate differences between patients with recurrent dislocation of the patella and normal control subjects.
Chronic patellofemoral instability can be a disabling condition. Management of patients with this condition has improved owing to our increased knowledge of the functional anatomy of the patellofemoral joint. Accurate assessment of the underlying pathology in the unstable joint enables the formulation of appropriate treatment. The surgical technique employed in patients for whom non-operative management has failed should address the diagnosed abnormality. We have reviewed the literature on the stabilising features of the patellofemoral joint, the recommended investigations and the appropriate forms of treatment.
We retrospectively analysed the MR scans of 25 patients with patellofemoral dysplasia and ten control subjects, to assess whether there was any change in the morphology of the patella along its vertical length. Ratios were calculated comparing the size of the cartilaginous and subchondral osseous surfaces of the lateral and medial facets. We also classified the morphology using the scoring systems of Baumgartl and Wiberg. There were 18 females and seven males with a mean age of 20.2 years (10 to 29) with dysplasia and two females and eight males with a mean age of 20.4 years (10 to 29) in the control group. In the patient group there was a significant difference in morphology from proximal to distal for the cartilaginous (Analysis of variance (ANOVA) p = 0.004) and subchondral osseous surfaces (ANOVA, p = 0.002). In the control group there was no significant difference for either the cartilaginous (ANOVA, p = 0.391) or the subchondral osseous surface (ANOVA, p = 0.526). Our study has shown that in the dysplastic patellofemoral articulation the medial facet of the patella becomes smaller in relation to the lateral facet from proximal to distal. MRI is needed to define clearly the cartilaginous and osseous morphology of the patella before surgery is considered for patients with patellofemoral dysplasia.
We investigated the three-dimensional morphological differences of the articular surface of the femoral trochlea in patients with recurrent dislocation of the patella and a normal control group using three-dimensional computer models. There were 12 patients (12 knees) and ten control subjects (ten knees). Three-dimensional computer models of the femur, including the articular cartilage, were created. Evaluation was performed on the shape of the articular surface, focused on its convexity, and the proximal and mediolateral distribution of the articular cartilage of the femoral trochlea. The extent of any convexity, and the proximal distribution of the articular cartilage, expressed as the height, were shown by the angles about the transepicondylar axis. The mediolateral distribution of the articular cartilage was assessed by the location of the medial and lateral borders of the articular cartilage. The mean extent of convexity was 24.9° Our findings therefore quantitatively demonstrated differences in the shape and distribution of the articular cartilage on the femoral trochlea between patients with dislocation of the patella and normal subjects.
We evaluated the survival of moulded monoblock and modular tibial components of the AGC total knee replacement in patients with rheumatoid arthritis. Between 1985 and 1995, 751 knees with this diagnosis were replaced at our institution. A total of 256 tibial components were of the moulded design and 495 of the modular design. The mean follow-up of the moulded subgroup was 9.6 years (0.5 to 14.7), and that of the modular group 7.0 years (0.1 to 14.7). The groups differed significantly from each other in Larsen grade, cementing of components and patellar resurfacing, but no statistically significant difference between the survival of the components was found (Log rank test, p = 0.91). The cumulative success rate of the moulded group was 96.8% (95% confidence interval 93.6% to 98.4%) at five years and 94.4% (95% confidence interval 90.4% to 96.7%) at ten years, and of the modular group 96.2% (95% confidence interval 94% to 97.6%) and 93.6% (95% confidence interval 89.7% to 96%), respectively. Revision was required in 37 total knee replacements, the main causes were infection, pain, loosening of the tibial component and patellar problems. Survival rates for both components were satisfactory.
Systemic emboli released during total knee replacement have been implicated as a cause of peri-operative morbidity and neurological dysfunction. We undertook a prospective, double-blind, randomised study to compare the cardiac embolic load sustained during computer-assisted and conventional, intramedullary-aligned, total knee replacement, as measured by transoesophageal echocardiography. There were 26 consecutive procedures performed by a single surgeon at a single hospital. The embolic load was scored using the modified Mayo grading system for echogenic emboli. Fourteen patients undergoing computer-assisted total knee replacement had a mean embolic score of 4.89 (3 to 7) and 12 undergoing conventional total knee replacement had a mean embolic score of 6.15 (4 to 8) on release of the tourniquet. Comparison of the groups using a two-tailed This study demonstrates that computer-assisted knee replacement results in the release of significantly fewer systemic emboli than the conventional procedure using intramedullary alignment.
One of the most controversial issues in total knee replacement is whether or not to resurface the patella. In order to determine the effects of different designs of femoral component on the conformity of the patellofemoral joint, five different knee prostheses were investigated. These were Low Contact Stress, the Miller-Galante II, the NexGen, the Porous-Coated Anatomic, and the Total Condylar prostheses. Three-dimensional models of the prostheses and a native patella were developed and assessed by computer. The conformity of the curvature of the five different prosthetic femoral components to their corresponding patellar implants and to the native patella at different angles of flexion was assessed by measuring the angles of intersection of tangential lines. The Total Condylar prosthesis had the lowest conformity with the native patella (mean 8.58°; 0.14° to 29.9°) and with its own patellar component (mean 11.36°; 0.55° to 39.19°). In the other four prostheses, the conformity was better (mean 2.25°; 0.02° to 10.52°) when articulated with the corresponding patellar component. The Porous-Coated Anatomic femoral component showed better conformity (mean 6.51°; 0.07° to 9.89°) than the Miller-Galante II prosthesis (mean 11.20°; 5.80° to 16.72°) when tested with the native patella. Although the Nexgen prosthesis had less conformity with the native patella at a low angle of flexion, this improved at mid (mean 3.57°; 1.40° to 4.56°) or high angles of flexion (mean 4.54°; 0.91° to 9.39°), respectively. The Low Contact Stress femoral component had the best conformity with the native patella (mean 2.39°; 0.04° to 4.56°). There was no significant difference (p >
0.208) between the conformity when tested with the native patella or its own patellar component at any angle of flexion. The geometry of the anterior flange of a femoral component affects the conformity of the patellofemoral joint when articulating with the native patella. A more anatomical design of femoral component is preferable if the surgeon decides not to resurface the patella at the time of operation.
Genu varum in the achondroplastic patient has a complex and multifactorial aetiology. There is little mention in the literature of the role of fibular overgrowth. Using the ratio of fibular to tibial length as a measurement of possible fibular overgrowth, we have related it to the development of genu varum. Full-length standing anteroposterior radiographs of 53 patients with achondroplasia were analysed. There were 30 skeletally-immature and 23 skeletally-mature patients. Regression analysis was performed in order to determine if there was a causal relationship between fibular overgrowth and the various indices of alignment of the lower limb. Analysis showed that the fibular to tibial length ratio had a significant correlation with the medial proximal tibial angle and the mechanical axial deviation in the skeletally-immature group. We conclude that there is a significant relationship between fibular overgrowth and the development of genu varum in the skeletally-immature achondroplastic patient.
Surgeons need to be able to measure angles and distances in three dimensions in the planning and assessment of knee replacement. Computed tomography (CT) offers the accuracy needed but involves greater radiation exposure to patients than traditional long-leg standing radiographs, which give very little information outside the plane of the image. There is considerable variation in CT radiation doses between research centres, scanning protocols and individual scanners, and ethics committees are rightly demanding more consistency in this area. By refining the CT scanning protocol we have reduced the effective radiation dose received by the patient down to the equivalent of one long-leg standing radiograph. Because of this, it will be more acceptable to obtain the three-dimensional data set produced by CT scanning. Surgeons will be able to document the impact of implant position on outcome with greater precision.
We carried out a prospective study of 118 hydroxyapatite-coated, cementless total knee replacements in patients who were ≤ 55 years of age and who had primary (92; 78%) or post-traumatic (26; 22%) osteoarthritis. The mean period of follow-up was 7.9 years (5 to 12.5). The Knee Society clinical scores improved from a pre-operative mean of 98 (0 to 137) to a mean of 185 (135 to 200) at five years, and 173 (137 to 200) at ten years. There were two revisions of the tibial component because of aseptic loosening, and one case of polyethylene wear requiring further surgery. There was no osteolysis or progressive radiological loosening of any other component. At 12 years, the overall rate of implant survival was 97.5% (excluding exchange of spacer) and 92.1% (including exchange of spacer). Cementless total knee replacement can achieve excellent long-term results in young, active patients with osteoarthritis. In contrast to total hip replacement, polyethylene wear, osteolysis and loosening of the prosthesis were not major problems for these patients, although it is possible that this observation could change with longer periods of follow-up.
A series of 100 consecutive osteoarthritic patients was randomised to undergo total knee replacement using a Miller-Galante II prosthesis, with or without a cemented polyethylene patellar component. Knee function was evaluated using the American Knee Society score, Western Ontario and McMaster University Osteoarthritis index, specific patellofemoral-related questions and radiographic evaluation until the fourth post-operative year, then via questionnaire until ten years post-operatively. A ten-point difference in the American Knee Society score between the two groups was considered a significant change in knee performance, with α and β levels of 0.05. The mean age of the patients in the resurfaced group was 71 years (53 to 88) and in the non-resurfaced group was 73 years (54 to 86). After ten years 22 patients had died, seven were suffering from dementia, three declined further participation and ten were lost to follow-up. Two patients in the non-resurfaced group subsequently had their
In 20 patients undergoing hybrid total hip arthroplasty, the reproducibility and accuracy of templating using digital radiographs were assessed. Digital images were manipulated using either a ten-pence coin as a marker to scale for magnification, or two digital-line methods using computer software. On-screen images were templated with standard acetate templates and compared with templating performed on hard-copy digital prints. The digital-line methods were the least reliable and accuracy of sizing compared with the inserted prostheses varied between −1.6% and +10.2%. The hard-copy radiographs showed better reproducibility than the ten-pence coin method, but were less accurate with 3.7% undersizing. The ten-pence coin method was the most accurate, with no significant differences for offset or acetabulum, and undersizing of only 0.9%. On-screen templating of digital radiographs with standard acetate templates is accurate and reproducible if a radiopaque marker such as a ten-pence coin is included when the original radiograph is taken.