Aims. Primary (or spontaneous) and secondary osteonecrosis of the knee
can lead to severe joint degeneration, for which either total or
unicompartmental arthroplasty may be considered. However, there
are limited studies analyzing outcomes of
The Oxford
While residual fixed flexion deformity (FFD) in unicompartmental knee arthroplasty (UKA) has been associated with worse functional outcomes, limited evidence exists regarding FFD changes. The objective of this study was to quantify FFD changes in patients with medial unicompartmental knee arthritis undergoing UKA, and investigate any correlation with clinical outcomes. This study included 136 patients undergoing robotic arm-assisted medial UKA between January 2018 and December 2022. The study included 75 males (55.1%) and 61 (44.9%) females, with a mean age of 67.1 years (45 to 90). Patients were divided into three study groups based on the degree of preoperative FFD: ≤ 5°, 5° to ≤ 10°, and > 10°. Intraoperative optical motion capture technology was used to assess pre- and postoperative FFD. Clinical FFD was measured pre- and postoperatively at six weeks and one year following surgery. Preoperative and one-year postoperative Oxford Knee Scores (OKS) were collected.Aims
Methods
Medium-term survivorship of the Oxford phase
3 unicompartmental knee replacement (UKR) has not yet been established
in an Asian population. We prospectively evaluated the outcome of
400 phase 3 Oxford UKRs in 320 Korean patients with a mean age at
the time of operation of 69 years (48 to 82). The mean follow-up
was 5.2 years (1 to 10). Clinical and radiological assessment was
carried out pre- and post-operatively. At five years, the mean Knee
Society knee and functional scores had increased significantly from
56.2 (30 to 91) pre-operatively to 87.2 (59 to 98) (p = 0.034) and
from 59.2 (30 to 93) to 88.3 (50 to 100) (p = 0.021), respectively.
The Oxford knee score increased from a mean of 25.8 (12 to 39) pre-operatively
to 39.8 (25 to 58) at five years (p = 0.038). The ten-year survival
rate was 94% (95% confidence interval 90.1 to 98.0). A total of
14 UKRs (3.5%) required revision. The most common reason for revision
was dislocation of the bearing in 12 (3%). Conversion to a total
knee replacement was required in two patients who developed osteoarthritis
of the lateral compartment. This is the largest published series of UKR in Korean patients.
It shows that the mid-term results after a minimally invasive Oxford
phase 3 UKR can yield satisfactory clinical and functional results
in this group of patients.
The Oxford mobile-bearing unicompartmental knee
replacement (UKR) is an effective and safe treatment for osteoarthritis
of the medial compartment. The results in the lateral compartment
have been disappointing due to a high early rate of dislocation
of the bearing. A series using a newly designed domed tibial component
is reported. The first 50 consecutive domed lateral Oxford UKRs in 50 patients
with a mean follow-up of three years (2.0 to 4.3) were included.
Clinical scores were obtained prospectively and Kaplan-Meier survival
analysis was performed for different endpoints. Radiological variables
related to the position and alignment of the components were measured. One patient died and none was lost to follow-up. The cumulative
incidence of dislocation was 6.2% (95% confidence interval (CI)
2.0 to 17.9) at three years. Survival using revision for any reason
and aseptic revision was 94% (95% CI 82 to 98) and 96% (95% CI 85
to 99) at three years, respectively. Outcome scores, visual analogue
scale for pain and maximum knee flexion showed a significant improvement
(p <
0.001). The mean Oxford knee score was 43 ( Clinical results are excellent and short-term survival has improved
when compared with earlier series. The risk of dislocation remains
higher using a mobile-bearing UKR in the lateral compartment when
compared with the medial compartment. Patients should be informed
about this complication. To avoid dislocations, care must be taken
not to elevate the lateral joint line.
Little is known about the relative outcomes of revision of unicompartmental
knee arthroplasty (UKA) and high tibial osteotomy (HTO) to total
knee arthroplasty (TKA). The aim of this study is to compare the
outcomes of revision surgery for the two procedures in terms of
complications, re-revision and patient-reported outcome measures (PROMs)
at a minimum of two years follow-up. This study was a retrospective review of data from an institutional
arthroplasty registry for cases performed between 2001 and 2014.
A total of 292 patients were identified, of which 217 had a revision
of HTO to TKA, and 75 had revision of UKA to TKA. While mean follow-up
was longer for the HTO group compared with the UKA group, patient
demographics (age, body mass index and Charlson co-morbidity index)
and PROMs (Short Form-36, Oxford Knee Score, Knee Society Score,
both objective and functional) were similar in the two groups prior
to revision surgery. Outcomes included the rate of complications
and
re-operation, PROMS and patient-reported satisfaction at six months
and two years post-operatively. We also compared the duration of
surgery and the need for revision implants in the two groups. Aims
Patients and Methods
Partial knee arthroplasty (PKA), either medial
or lateral
The cementless Oxford
The purpose of this study is to determine an individual’s age-specific prevalence of total knee arthroplasty (TKA) after cruciate ligament surgery, and to identify clinical and genetic risk factors associated with undergoing TKA. This study was a retrospective case-control study using the UK Biobank to identify individuals reporting a history of cruciate ligament surgery. Data from verbal history and procedural codes recorded through the NHS were used to identify instances of TKA. Patient clinical and genetic data were used to identify risk factors for progression from cruciate ligament surgery to TKA. Individuals without a history of cruciate ligament reconstruction were used for comparison.Aims
Methods
Unicompartmental knee arthroplasty (UKA) has higher revision rates than total knee arthroplasty (TKA). As revision of UKA may be less technically demanding than revision TKA, UKA patients with poor functional outcomes may be more likely to be offered revision than TKA patients with similar outcomes. The aim of this study was to compare clinical thresholds for revisions between TKA and UKA using revision incidence and patient-reported outcomes, in a large, matched cohort at early, mid-, and late-term follow-up. Analyses were performed on propensity score-matched patient cohorts of TKAs and UKAs (2:1) registered in the New Zealand Joint Registry between 1 January 1999 and 31 December 2019 with an Oxford Knee Score (OKS) response at six months (n, TKA: 16,774; UKA: 8,387), five years (TKA: 6,718; UKA: 3,359), or ten years (TKA: 3,486; UKA: 1,743). Associations between OKS and revision within two years following the score were examined. Thresholds were compared using receiver operating characteristic analysis. Reasons for aseptic revision were compared using cumulative incidence with competing risk.Aims
Methods
Mobile-bearing
The Cementless Oxford
The optimal bearing surface design for medial unicompartmental knee arthroplasty (UKA) remains controversial. The aim of this study was to compare outcomes of fixed-bearing (FB) and mobile-bearing (MB) UKAs from a single high-volume institution. Prospectively collected data were reviewed for all primary cemented medial UKAs performed by seven surgeons from January 2006 to December 2022. A total of 2,999 UKAs were identified, including 2,315 FB and 684 MB cases. The primary outcome measure was implant survival. Secondary outcomes included 90-day and cumulative complications, reoperations, component revisions, conversion arthroplasties, range of motion, and patient-reported outcome measures. Overall mean age at surgery was 65.7 years (32.9 to 94.3), 53.1% (1,593/2,999) of UKAs were implanted in female patients, and demographics between groups were similar (p > 0.05). The mean follow-up for all UKAs was 3.7 years (0.0 to 15.6).Aims
Methods
We assessed the outcome of patients who were
lost to follow-up after arthroplasty by a single surgeon. The aim was
to validate the surgeon’s data set with the Australian Orthopaedic
Association National Joint Replacement Registry and determine the
outcome of those patients lost to follow-up. Prospective data on patient demographics, operative details and
outcomes of the surgeon’s 1192 primary
Ideal component sizing may be difficult to achieve in unicompartmental knee arthroplasty (UKA). Anatomical variants, incremental implant size, and a reduced surgical exposure may lead to over- or under-sizing of the components. The purpose of this study was to compare the accuracy of UKA sizing with robotic-assisted techniques versus a conventional surgical technique. Three groups of 93 medial UKAs were assessed. The first group was performed by a conventional technique, the second group with an image-free robotic-assisted system (Image-Free group), and the last group with an image-based robotic arm-assisted system, using a preoperative CT scan (Image-Based group). There were no demographic differences between groups. We compared six parameters on postoperative radiographs to assess UKA sizing. Incorrect sizing was defined by an over- or under-sizing greater than 3 mm.Aims
Methods
This study aims to evaluate a new home medical stretching device called the Self Treatment Assisted Knee (STAK) tool to treat knee arthrofibrosis. 35 patients post-major knee surgery with arthrofibrosis and mean range of movement (ROM) of 68° were recruited. Both the STAK intervention and control group received standard physiotherapy for eight weeks, with the intervention group additionally using the STAK at home. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Oxford Knee Scores (OKS) were collected at all timepoints. An acceptability and home exercise questionnaire capturing adherence was recorded after each of the interventions.Aims
Methods
Commonly performed unicompartmental knee arthroplasty (UKA) is not designed for the lateral compartment. Additionally, the anatomical medial and lateral tibial plateaus have asymmetrical geometries, with a slightly dished medial plateau and a convex lateral plateau. Therefore, this study aims to investigate the native knee kinematics with respect to the tibial insert design corresponding to the lateral femoral component. Subject-specific finite element models were developed with tibiofemoral (TF) and patellofemoral joints for one female and four male subjects. Three different TF conformity designs were applied. Flat, convex, and conforming tibial insert designs were applied to the identical femoral component. A deep knee bend was considered as the loading condition, and the kinematic preservation in the native knee was investigated.Aims
Methods
The aim of this study was to determine the polyethylene wear rate of Phase 3 Oxford Unicompartmental Knee Replacement bearings and to investigate the effects of resin type and manufacturing process. A total of 63 patients with at least ten years’ follow-up with three bearing types (1900 resin machined, 1050 resin machined, and 1050 resin moulded) were recruited. Patients underwent full weight-bearing model-based radiostereometric analysis to determine the bearing thickness. The linear wear rate was estimated from the change in thickness divided by the duration of implantation.Objectives
Methods
There has been a recent resurgence in interest in combined partial knee arthroplasty (PKA) as an alternative to total knee arthroplasty (TKA). The varied terminology used to describe these procedures leads to confusion and ambiguity in communication between surgeons, allied health professionals, and patients. A standardized classification system is required for patient safety, accurate clinical record-keeping, clear communication, correct coding for appropriate remuneration, and joint registry data collection. An advanced PubMed search was conducted, using medical subject headings (MeSH) to identify terms and abbreviations used to describe knee arthroplasty procedures. The search related to TKA, unicompartmental (UKA), patellofemoral (PFA), and combined PKA procedures. Surveys were conducted of orthopaedic surgeons, trainees, and biomechanical engineers, who were asked which of the descriptive terms and abbreviations identified from the literature search they found most intuitive and appropriate to describe each procedure. The results were used to determine a popular consensus.Aims
Materials and Methods
The primary aim of this study was to determine the surgical team’s
learning curve for introducing robotic-arm assisted unicompartmental
knee arthroplasty (UKA) into routine surgical practice. The secondary
objective was to compare accuracy of implant positioning in conventional
jig-based UKA versus robotic-arm assisted UKA. This prospective single-surgeon cohort study included 60 consecutive
conventional jig-based UKAs compared with 60 consecutive robotic-arm
assisted UKAs for medial compartment knee osteoarthritis. Patients
undergoing conventional UKA and robotic-arm assisted UKA were well-matched
for baseline characteristics including a mean age of 65.5 years
(Aims
Patients and Methods