Aims. The mid-term results of kinematic
The kinematic
Dissatisfaction following total knee arthroplasty is a well-documented phenomenon. Although many factors have been implicated, including modifiable and nonmodifiable patient factors, emphasis over the past decade has been on implant
Objectives. Unicompartmental knee arthroplasty (UKA) is one surgical option for treating symptomatic medial osteoarthritis. Clinical studies have shown the functional benefits of UKA; however, the optimal
We compared lower limb coronal
We performed a randomised controlled trial comparing
computer-assisted surgery (CAS) with conventional surgery (CONV)
in total knee replacement (TKR). Between 2009 and 2011 a total of
192 patients with a mean age of 68 years (55 to 85) with osteoarthritis
or arthritic disease of the knee were recruited from four Norwegian
hospitals. At three months follow-up, functional results were marginally
better for the CAS group. Mean differences (MD) in favour of CAS
were found for the Knee Society function score (MD: 5.9, 95% confidence
interval (CI) 0.3 to 11.4, p = 0.039), the Knee Injury and Osteoarthritis
Outcome Score (KOOS) subscales for ‘pain’ (MD: 7.7, 95% CI 1.7 to
13.6, p = 0.012), ‘sports’ (MD: 13.5, 95% CI 5.6 to 21.4, p = 0.001)
and ‘quality of life’ (MD: 7.2, 95% CI 0.1 to 14.3, p = 0.046).
At one-year follow-up, differences favouring CAS were found for
KOOS ‘sports’ (MD: 11.0, 95% CI 3.0 to 19.0, p = 0.007) and KOOS
‘symptoms’ (MD: 6.7, 95% CI 0.5 to 13.0, p = 0.035). The use of
CAS resulted in fewer outliers in frontal
We conducted a meta-analysis, including randomised
controlled trials (RCTs) and cohort studies, to examine the effect
of patient-specific instruments (PSI) on radiological outcomes after
total knee replacement (TKR) including: mechanical axis alignment
and malalignment of the femoral and tibial components in the coronal,
sagittal and axial planes, at a threshold of >
3º from neutral.
Relative risks (RR) for malalignment were determined for all studies
and for RCTs and cohort studies separately. Of 325 studies initially identified, 16 met the eligibility criteria,
including eight RCTs and eight cohort studies. There was no significant
difference in the likelihood of mechanical axis malalignment with
PSI versus conventional TKR across all studies
(RR = 0.84, p = 0.304), in the RCTs (RR = 1.14, p = 0.445) or in
the cohort studies (RR = 0.70, p = 0.289). The results for the alignment
of the tibial component were significantly worse using PSI TKR than conventional
TKR in the coronal and sagittal planes (RR = 1.75, p = 0.028; and
RR = 1.34, p = 0.019, respectively, on pooled analysis). PSI TKR
showed a significant advantage over conventional TKR for alignment
of the femoral component in the coronal plane (RR = 0.65, p = 0.028
on pooled analysis), but not in the sagittal plane (RR = 1.12, p =
0.437). Axial
Aims. This study aimed to evaluate if total knee arthroplasty (TKA) femoral components aligned in either mechanical
Aims. While mechanical
Purpose. Various
Orthopaedic surgeons are currently faced with an overwhelming number of choices surrounding total knee arthroplasty (TKA), not only with the latest technologies and prostheses, but also fundamental decisions on
Aims. Patient-specific instrumentation of total knee arthroplasty (TKA) is a technique permitting the targeting of individual kinematic
Aims. Accurate identification of the ankle joint centre is critical for estimating tibial coronal
Aims. The Coronal Plane
Malalignment is often postulated as the main reason for the high failure rate of total ankle replacements (TARs). Only a few studies have been performed to correlate radiographic TAR malalignment to the clinical outcome, but no consistent trends between TAR
Aims. Alternative
This study aimed to examine the effect of high tibial osteotomy (HTO) on the ankle and subtalar joints via analysis of static radiographic
Aims. A comprehensive classification for coronal lower limb
Cranio-cervical connection is a well-established biomechanical concept. However, literature of this connection and its impact on cervical
Aims. The impact of a diaphyseal femoral deformity on knee
Aims. The aims of this study were: 1) to describe extended restricted kinematic
Aims. The aim of this study was to determine the association between knee
Background. A principle of Total Knee Arthroplasty (TKA) is to achieve a neutral standing coronal
A principle of Total Knee Arthroplasty (TKA) is to achieve a neutral standing coronal
INTRODUCTION. While standard instrumentation tries to reproduce mechanical axes based on mechanical
Varus ankle osteoarthritis (OA) is typically associated with peritalar instability, which may result in altered subtalar joint position. This study aimed to determine the extent to which total ankle replacement (TAR) in varus ankle OA can restore the subtalar position
Introduction. Component and limb
The emergence of patient specific instrumentation has seen an expansion from simple radiographs to plan total knee arthroplasty (TKA) with modern systems using computed tomography (CT) or magnetic resonance imaging scans. Concerns have emerged regarding accuracy of these non-weight bearing modalities to assess true mechanical axis. The aim of our study was to compare coronal
Aims. Total knee arthroplasty (TKA) using functional
A medializing calcaneal osteotomy (MCO) is one of the key inframalleolar osteotomies to correct progressive collapsing foot deformity (PCFD). While many studies were able to determine the hind- and midfoot
Known risk factors for early periprosthetic femur fracture (PFF) following total hip arthroplasty (THA) include poor bone quality, surgical approach and cementless implants. The association between femoral component size and
Abstract. Introduction. Controversy exists regarding the optimal tibial coronal
Mechanical
Aims. Nearly 99,000 total knee arthroplasties (TKAs) are performed in UK annually. Despite plenty of research, the satisfaction rate of this surgery is around 80%. One of the important intraoperative factors affecting the outcome is
Aims. Once knee arthritis and deformity have occurred, it is currently not known how to determine a patient’s constitutional (pre-arthritic) limb
The spinopelvic
Aims. Robotic-assisted total knee arthroplasty (RA-TKA) is theoretically more accurate for component positioning than TKA performed with mechanical instruments (M-TKA). Furthermore, the ability to incorporate soft-tissue laxity data into the plan prior to bone resection should reduce variability between the planned polyethylene thickness and the final implanted polyethylene. The purpose of this study was to compare accuracy to plan for component positioning and precision, as demonstrated by deviation from plan for polyethylene insert thickness in measured-resection RA-TKA versus M-TKA. Methods. A total of 220 consecutive primary TKAs between May 2016 and November 2018, performed by a single surgeon, were reviewed. Planned coronal plane component
Aims. Patients with a deformity of the hindfoot present a particular challenge when performing total knee arthroplasty (TKA). The literature contains little information about the relationship between TKA and hindfoot
Introduction. Varus
Aims. The aim of this study is to test the hypothesis that three grades of sagittal compensation for standing posture (normal, compensated, and decompensated) correlate with health-related quality of life measurements (HRQOL). Methods. A total of 50 healthy volunteers (normal), 100 patients with single-level lumbar degenerative spondylolisthesis (LDS), and 70 patients with adult to elderly spinal deformity (deformity) were enrolled. Following collection of demographic data and HRQOL measured by the Scoliosis Research Society-22r (SRS-22r), radiological measurement by the biplanar slot-scanning full body stereoradiography (EOS) system was performed simultaneously with force-plate measurements to obtain whole body sagittal
Aims. The aim of this study was to compare robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) in order to determine the changes in the anatomy of the knee and
Accurate evaluation of lower limb coronal
Dislocation is one of the most common complications in total hip arthroplasty (THA) and is primarily driven by bony or prosthetic impingement. The aim of this study was two-fold. First, to develop a simulation that incorporates the functional position of the femur and pelvis and instantaneously determines range of motion (ROM) limits. Second, to assess the number of patients for whom their functional bony
In total knee replacement (TKR), neutral mechanical
We undertook a prospective, randomised study of 135 total knee arthroplasties to determine the most accurate and reliable technique for
Inverse Kinematic
Aims. The extensive variation in axial rotation of tibial components can lead to coronal plane malalignment. We analyzed the change in coronal
Aims. 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
INTRODUCTION. In total knee arthroplasty (TKA), the effectiveness of the mechanical
Identifying and restoring
Introduction. Malalignment of total knee arthroplasty components may affect implant function and lead to decreased survival, regardless of preferred
Aims. The aim of this study was to investigate the distribution of phenotypes in Asian patients with end-stage osteoarthritis (OA) and assess whether the phenotype affected the clinical outcome and survival of mechanically aligned total knee arthroplasty (TKA). We also compared the survival of the group in which the phenotype unintentionally remained unchanged with those in which it was corrected to neutral. Methods. The study involved 945 TKAs, which were performed in 641 patients with primary OA, between January 2000 and January 2009. These were classified into 12 phenotypes based on the combined assessment of four categories of the arithmetic hip-knee-ankle angle and three categories of actual joint line obliquity. The rates of survival were analyzed using Kaplan-Meier methods and the log-rank test. The Hospital for Special Surgery score and survival of each phenotype were compared with those of the reference phenotype with neutral
Introduction. Proper rotational
Introduction. Robotics have been applied to total knee arthroplasty (TKA) to improve surgical precision in component placement and joint function restoration. The purpose of this study was to evaluate prosthetic component
Aims. The purpose of this study was to compare the radiological outcomes of manual versus robotic-assisted medial unicompartmental knee arthroplasty (UKA). Methods. Postoperative radiological outcomes from 86 consecutive robotic-assisted UKAs (RAUKA group) from a single academic centre were retrospectively reviewed and compared to 253 manual UKAs (MUKA group) drawn from a prior study at our institution. Femoral coronal and sagittal angles (FCA, FSA), tibial coronal and sagittal angles (TCA, TSA), and implant overhang were radiologically measured to identify outliers. Results. When assessing the accuracy of RAUKAs, 91.6% of all
Abstract. Introduction. Coronal plane
Abstract. Introduction. Long term survivorship in Total Knee Arthroplasty is significantly dependent on prosthesis
Abstract. Background. Conventional TKR aims for neutral mechanical
Cervical spine facet tropism (CFT) defined as the facets’ joints angles difference between right and left sides of more than 7 degrees. This study aims to investigate the relationship between cervical sagittal
Several emerging reports suggest an important involvement of the hindfoot
Tibial plateau fracture reduction involves restoration of
Aims. An algorithm to determine the constitutional
Introduction. Intraoperative assessment of coronal
Robotic-assisted technology in total knee arthroplasty (TKA) aims to increase implantation accuracy, with real-time data being used to estimate intraoperative component
Background. Advanced technologies, like robotics, provide enhanced precision for implanting total knee arthroplasty (TKA) components; however, optimal component position and limb
Introduction. Component position and overall limb
Constrained implants with intra-medullary fixation are expedient for complex TKA. Constraint is associated with loosening, but can correction of deformity mitigate risk of loosening?. Primary TKA's with a non-linked constrained prosthesis from 2010-2018 were identified. Indications were ligamentous instability or intra-medullary fixation to bypass stress risers. All included fully cemented 30mm stem extensions on tibia and femur. If soft tissue stability was achieved, a posterior stabilized (PS) tibial insert was selected. Pre and post TKA full length radiographs showed. i. hip-knee-ankle angles (HKAA). ii. Kennedy Zone (KZ) where hip to ankle vector crosses knee joint. 77 TKA's in 68 patients, average age 69.3 years (41-89.5) with OA (65%) post-trauma (24.5%) and inflammatory arthropathy (10.5%). Pre-op radiographs (62 knees) showed varus in 37.0%. (HKAA: 4. o. -29. o. ), valgus in 59.6% (HKAA range 8. o. -41. o. ) and 2 knees in neutral. 13 cases deceased within 2 years were excluded. Six with 2 year follow up pending have not been revised. Mean follow-up is 6.1 yrs (2.4-11.9yrs). Long post-op radiographs showed 34 (57.6%) in central KZ (HKKA 180. o. +/- 2. o. ). . Thirteen (22.0%) were in mechanical varus (HKAA 3. o. -15. o. ) and 12 (20.3%) in mechanical valgus: HKAA (171. o. -178. o. ). Three failed with infection; 2 after ORIF and one with BMI>50. The greatest post op varus suffered peri-prosthetic fracture. There was no aseptic loosening or instability. Only full-length radiographs accurately measure
Background. The complex deformities in cavovarus feet may be difficult to assess and understand. Weight-bearing CT (WBCT) is increasingly used to evaluate complex deformities. However, the bone axes may be difficult to calculate in the setting of severe deformity. Computer-assisted 3D-axis calculation is a novel approach that may allow for more accurate assessment of foot
Mechanical
Introduction. By utilising the inherent variability achievable with circular frames, surgeons can manage a wide spectrum of complex injuries, and can deal with deformity at multiple levels, in multiple planes. The aim of this study was to assess functional outcomes utilising patients reported outcome measures (PROMs) of patients being treated with circular (Ilizarov) frame fixation for complex lower limb injuries and assess these results in conjunction with the observed postoperative
Aims. This study aimed to evaluate sagittal spinopelvic
Introduction and Aims. Sensor technology is seeing increased utility in joint arthroplasty, guiding surgeons in assessing the soft tissue envelope intra-operatively (OrthoSensor, FL, USA). Meanwhile, surgical navigation systems are also transforming, with the recent introduction of inertial measurement unit (IMU) based systems no longer requiring optical trackers and infrared camera systems in the operating room (i.e. OrthAlign, CA, USA). Both approaches have now been combined by embedding an IMU into an intercompartmental load sensor. As a result, the
The advent of computer-assisted knee replacement surgery has focused interest on the
Introduction. Achieving a balanced joint with neutral
Aims. The aims of this study were to determine the change in the sagittal
Patients with a hindfoot deformity impose a particular challenge when performing a total knee arthroplasty (TKA). This could be attributed to the lack of insights concerning the outcome towards the hindfoot
The restoration of knee
Introduction. Patellofemoral arthroplasty (PFA) can give excellent results in well-selected patients. Axial
Introduction. To control implant
Aims. The aims of this study were to determine the effect of osteophyte excision on deformity correction and soft tissue gap balance in varus knees undergoing computer-assisted total knee arthroplasty (TKA). Methods. A total of 492 consecutive, cemented, cruciate-substituting TKAs performed for varus osteoarthritis were studied. After exposure and excision of both cruciates and menisci, it was noted from operative records the corrective interventions performed in each case. Knees in which no releases after the initial exposure, those which had only osteophyte excision, and those in which further interventions were performed were identified. From recorded navigation data, coronal and sagittal limb
Aims. It is unknown whether kinematic
Abstract. Background. Lower limb mechanical axis has long been seen as a key to successful in lower limb surgery, including knee arthroplasty. Traditionally, coronal
Aims. This study aimed to identify the tibial component and femoral component coronal angles (TCCAs and FCCAs), which concomitantly are associated with the best outcomes and survivorship in a cohort of fixed-bearing, cemented, medial unicompartmental knee arthroplasties (UKAs). We also investigated the potential two-way interactions between the TCCA and FCCA. Methods. Prospectively collected registry data involving 264 UKAs from a single institution were analyzed. The TCCAs and FCCAs were measured on postoperative radiographs and absolute angles were analyzed. Clinical assessment at six months, two years, and ten years was undertaken using the Knee Society Knee score (KSKS) and Knee Society Function score (KSFS), the Oxford Knee Score (OKS), the 36-Item Short-Form Health Survey questionnaire (SF-36), and range of motion (ROM). Fulfilment of expectations and satisfaction was also recorded. Implant survivorship was reviewed at a mean follow-up of 14 years (12 to 16). Multivariate regression models included covariates, TCCA, FCCA, and two-way interactions between them. Partial residual graphs were generated to identify angles associated with the best outcomes. Kaplan-Meier analysis was used to compare implant survivorship between groups. Results. Significant two-way interaction effects between TCCA and FCCA were identified. Adjusted for each other and their interaction, a TCCA of between 2° and 4° and a FCCA of between 0° and 2° were found to be associated with the greatest improvements in knee scores and the probability of fulfilling expectations and satisfaction at ten years. Patients in the optimal group whose TCCA and FCCA were between 2° and 4°, and 0° and 2°, respectively, had a significant survival benefit at 15 years compared with the non-optimal group (optimal: survival = 100% vs non-optimal: survival = 92%, 95% confidence interval (CI) 88% to 96%). Conclusion. Significant two-way interactions between the TCCA and FCCA demonstrate the importance of evaluating the
Substantial healthcare resources have been devoted
to computer navigation and patient-specific instrumentation systems
that improve the reproducibility with which neutral mechanical alignment
can be achieved following total knee replacement (TKR). This choice of
alignment is based on the long-held tenet that the
Posterior stabilized (PS) total knee arthroplasty (TKA), wherein mechanical engagement of the femoral cam and tibial post prevents abnormal anterior sliding of the knee, is a proven surgical technique. However, many patients complain about abnormal clicking sensation, and several reports of severe wear and catastrophic failure of the tibial post have been published. In addition to posterior cam-post engagement during flexion, anterior engagement with femoral intercondylar notch can also occur during extension. The goal of this study was to use dynamic simulations to explore sensitivity of tibial post loading to implant design and
The mechanical
Objectives. Normal sagittal spine-pelvis-lower extremity
In general, “alignment” refers to the position of all components in three dimensions. This discussion is limited to “varus-valgus” (v-v)
Background.
The mechanical
No, Neutral mechanical axis has never been regarded as “necessary” to the success of TKA. In fact it has never been established as “ideal” with published data. Tibial femoral
Even though primary total knee arthroplasty involves resurfacing the joint with metal and plastic it is much more of a soft tissue operation than it is a bony procedure. The idea that altering the planned bony resection by a few degrees on either the tibial or femoral side of the joint might somehow eliminate the multifactorial pain complaints and reduced patient satisfaction seen in some 20% or more of cases in reported clinical series is clearly overly optimistic. Axial
Aims. We conducted a randomised controlled trial to assess the accuracy
of positioning and
Background. There have been multiple techniques described to determine hindfoot
Component
One of the main surgical goals when performing a total knee replacement (TKR) is to ensure the implants are properly aligned and correctly sized; however, understanding the effect of
Total elbow arthroplasty (TEA) usage is increasing owing to expanded surgical indications, better implant designs, and improved long-term survival. Correct humeral implant positioning has been shown to diminish stem loading in vitro, and radiographic loosening in in the long-term. Replication of the native elbow centre of rotation is thought to restore normal muscle moment arms and has been suggested to improve elbow strength and function. While much of the focus has been on humeral component positioning, little is known about the effect of positioning of the ulnar stem on post-operative range of motion and clinical outcomes. The purpose of this study is to determine the effect of the sagittal
Most discussions of
Introduction. Restoration of a neutral mechanical axis has been a widely held tenet of primary total knee arthroplasty (TKA), however new technologies are recently being marketed which claim correction of