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
Unicompartmental knee arthroplasty (UKA) is the preferred treatment for anterior medial knee osteoarthritis (OA) owing to the rapid postoperative recovery. However, the risk factors for UKA failure remain controversial. The clinical data of Oxford mobile-bearing UKAs performed between 2011 and 2017 with a minimum follow-up of five years were retrospectively analyzed. Demographic, surgical, and follow-up data were collected. The Cox proportional hazards model was used to identify the risk factors that contribute to UKA failure. Kaplan-Meier survival was used to compare the effect of the prosthesis position on UKA survival.Aims
Methods
Aims. Medial unicompartmental knee arthroplasty (UKA) is undertaken in patients with a passively correctable varus deformity. Our hypothesis was that restoration of natural soft tissue tension would result in a comparable lower limb alignment with the contralateral normal lower limb after
Purpose. We aimed to investigate whether the anterior superior iliac spine could provide consistent rotational landmark of the tibial component during
Aims. The aims of this retrospective study were to determine the incidence of extra-articular deformities (EADs), and determine their effect on postoperative alignment in knees undergoing
Enhanced appreciation of normal knee kinematics and the inability to replicate these in the replaced total knee has led to increased enthusiasm for partial knee arthroplasty by some. These arthroplasties more closely replicate normal kinematics since they inherently preserve the anterior cruciate ligament (ACL). Indications for medial UKA are: anteromedial osteoarthritis with an intact ACL, posterior cruciate ligament, and medial collateral ligament (MCL), full thickness cartilage loss, and correctable deformity demonstrated radiographically with valgus stress view; full thickness cartilage laterally with no central ulcer; <15 degrees of flexion contracture, < 15 degrees varus and > 90 degrees flexion. The state of the patellofemoral joint, chondrocalcinosis, obesity, age and activity level are NOT contraindications to medial mobile-bearing UKA. The only certain contraindications are the presence of inflammatory arthritis or a history of previous high tibial osteotomy (HTO). Advantages of medial UKA are that it preserves undamaged structures, it is a minimally invasive technique with low incidence of perioperative morbidity, preservation of the cruciate mechanism results in more “normal” kinematics versus TKA, it normalises contact forces and pressures in the patellofemoral joint, and it provides better range of motion than TKA. Furthermore, medial UKA results in better function than TKA in gait studies, with demanding activities, such as climbing stairs, having a better “feel”. Pain relief with medial UKA is equivalent or better than TKA, and morbidity and mortality are decreased compared with TKA, as well as venous thromboembolism. Recommended preoperative imaging studies consist of plain radiographs with the following views obtained: standing AP, PA flexed, lateral, Merchant or axial, and valgus stress. There are several surgical perils associated with performing medial UKA. First, in regard to patient selection, avoid medial UKA in patients with residual hyaline cartilage – the joint must be bone on bone. Second, perform a conservative tibial resection with respect to depth to prevent tibial collapse as well as excessive overload of weakened bone, and avoid excessive posterior slope. Perform the tibial resection coplanar with tibial spine/ACL insertion to maximise tibial coverage. Avoid overcorrection of deformity. Do not perform a medial release. Balance flexion/extension gaps meticulously. For mobile-bearing designs, remove all impinging osteophytes. Over 55 published studies report results with
The December 2023 Knee Roundup360 looks at: Obesity is associated with greater improvement in patient-reported outcomes following primary total knee arthroplasty; Does mild flexion of the femoral prosthesis in total knee arthroplasty result in better early postoperative outcomes?; Robotic or manual total knee arthroplasty: a randomized controlled trial; Patient-relevant outcomes following first revision total knee arthroplasty, by diagnosis: an analysis of implant survivorship, mortality, serious medical complications, and patient-reported outcome measures using the National Joint Registry data set; Sagittal alignment in total knee arthroplasty: are there any discrepancies between robotic-assisted and manual axis orientation?; Tourniquet use does not impact recovery trajectory in total knee arthroplasty; Impact of proximal tibial varus anatomy on survivorship after medial unicondylar knee arthroplasty; Bone cement directly to the implant in primary total knee arthroplasty?; Maintaining joint line obliquity optimizes outcomes in patients with constitutionally varus knees.
Unicompartmental knee arthroplasty (UKA) and bicompartmental knee arthroplasty (BCA) have been associated with improved functional outcomes compared to total knee arthroplasty (TKA) in suitable patients, although the reason is poorly understood. The aim of this study was to measure how the different arthroplasties affect knee extensor function. Extensor function was measured for 16 cadaveric knees and then retested following the different arthroplasties. Eight knees underwent medial UKA then BCA, then posterior-cruciate retaining TKA, and eight underwent the lateral equivalents then TKA. Extensor efficiency was calculated for ranges of knee flexion associated with common activities of daily living. Data were analyzed with repeated measures analysis of variance (α = 0.05).Aims
Methods
It is not clear whether anterior knee pain and osteoarthritis
(OA) of the patellofemoral joint (PFJ) are contraindications to
medial unicompartmental knee arthroplasty (UKA). Our aim was to
investigate the long-term outcome of a consecutive series of patients,
some of whom had anterior knee pain and PFJ OA managed with UKA. We assessed the ten-year functional outcomes and 15-year implant
survival of 805 knees (677 patients) following medial mobile-bearing
UKA. The intra-operative status of the PFJ was documented and, with
the exception of bone loss with grooving to the lateral side, neither
the clinical or radiological state of the PFJ nor the presence of
anterior knee pain were considered a contraindication. The impact
of radiographic findings and anterior knee pain was studied in a
subgroup of 100 knees (91 patients).Aims
Patients and Methods
Approved by the Food and Drug Administration in 2004, the Phase
III Oxford Medial Partial Knee is used to treat anteromedial osteoarthritis
(AMOA) in patients with an intact anterior cruciate ligament. This
unicompartmental knee arthroplasty (UKA) is relatively new in the
United States, and therefore long-term American results are lacking. This is a single surgeon, retrospective study based on prospectively
collected data, analysing a consecutive series of primary UKAs using
the Phase III mobile-bearing Oxford Knee and Phase III instrumentation. Between July 2004 and December 2006, the senior author (RHE)
carried out a medial UKA in 173 patients (213 knees) for anteromedial
osteoarthritis or avascular necrosis (AVN). A total of 95 patients were men and 78 were women. Their mean
age at surgery was 67 years (38 to 89) and mean body mass index
29.87 kg/m2 (17 to 62). The mean follow-up was ten years (4 to 11).Aims
Patients and Methods