Aims. 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. Methods. 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. Results. There were 4,135 TKAs (2,068 resurfaced and 2,027 unresurfaced) identified in 35 separate cohorts from 33 peer-reviewed studies. Anterior knee pain rates were significantly higher in unresurfaced knees overall (odds ratio (OR) 1.84; 95% confidence interval (CI) 1.20 to 2.83; p = 0.006) but more specifically associated with CR implants (OR 1.95; 95% CI 1.0 to 3.52; p = 0.030). There was a significantly better Knee Society function score (mean difference (MD) -1.98; 95% CI -1.1 to -2.84; p < 0.001) and Oxford Knee Score (MD -2.24; 95% CI -0.07 to -4.41; p = 0.040) for
Introduction. Early complication post total knee replacement reported to be higher in obese patient in general. Also the outcome of cruciate retaining and PS knee has been fully discussed before and there was no major difference in the outcome. However, the purpose of this paper is to find out if early complication postTKR such as fracture and instability is more common in
Aims. We have previously reported the mid-term outcomes of revision total knee arthroplasty (TKA) for flexion instability. At a mean of four years, there were no re-revisions for instability. The aim of this study was to report the implant survivorship and clinical and radiological outcomes of the same cohort of of patients at a mean follow-up of ten years. Methods. The original publication included 60 revision TKAs in 60 patients which were undertaken between 2000 and 2010. The mean age of the patients at the time of revision TKA was 65 years, and 33 (55%) were female. Since that time, 21 patients died, leaving 39 patients (65%) available for analysis. The cumulative incidence of any re-revision with death as a competing risk was calculated. Knee Society Scores (KSSs) were also recorded, and updated radiographs were reviewed. Results. The cumulative incidence of any re-revision was 13% at a mean of ten years. At the most recent-follow-up, eight TKAs had been re-revised: three for recurrent flexion instability (two fully revised to varus-valgus constrained implants (VVCs), and one posterior-stabilized (PS) implant converted to VVC, one for global instability (PS to VVC), two for aseptic loosening of the femoral component, and two for periprosthetic joint infection). The ten-year cumulative incidence of any re-revision for instability was 7%. The median KSS improved significantly from 45 (interquartile range (IQR) 40 to 50) preoperatively to 70 (IQR 45 to 80) at a mean follow-up of ten years (p = 0.031). Radiologically, two patients, who had not undergone revision, had evidence of loosening (one tibial and one patellar). The remaining components were well fixed. Conclusion. We found fair functional outcomes and implant survivorship at a mean of ten years after revision TKA for flexion instability with a
Introduction. Early complication post total knee replacement reported to be higher in obese patient in general. Also the outcome of cruciate retaining and PS knee has been fully discussed before and there was no major difference in the outcomes for all the patients overall regardless of their weight. However, the purpose of this paper is to find out if the CR knee has superiority over PS knee in terms of clinical and functional outcomes and if early complication postTKR such as fracture and instability is more common in
Background. In this study, we assessed implant survivorship, patient satisfaction, and patient-reported functional outcomes at two years for patients implanted with a customized, posterior stabilized knee replacement system. Methods. Ninety-three patients (100 knees) with the customized PS TKR were enrolled at two centers. Patients’ length of hospitalization and preoperative pain intensity were assessed. At a single time point follow-up, we assessed patient reported outcomes utilizing the KOOS Jr., satisfaction rates, implant survivorship, patients’ perception of their knee and their overall preference between the two knees, if they had their contralateral knee replaced with an off-the-shelf (OTS) implant. Results. At an average of 1.9-years implant survivorship was found to be 100%. From pre-op until time of follow-up, we observed an average decrease of 5.4 on the numeric pain rating scale. Satisfaction rate was found to be high with 90% of patients being satisfied or very satisfied and 88% of patients reporting a “natural” perception of their knee some or all the time. Patients with bilateral implants mostly (12/15) stated that they preferred their customized implant over the standard TKR. The evaluation of KOOS Jr. showed an average score of 90 at the time of the follow up. Conclusion. Based on our results, we believe that the customized
Introduction. Large variations in knee kinematics existed after conventional TKA. Different design of TKA showed different intra-operative kinematics with navigation system. Purpose. The purpose of this study was to compare the kinematics of the three different types of prosthesis in navigation-based in vivo simulation. (Material and Method) Studies were carried out on 15 osteoarthritis Knees using the CT-free navigation system (Kolibri Knee, Brain LAB). Fourteen patients were female and one patient was male with mean age of 72 years. Five knees were implanted with the CR knee, 5 knees were implanted with the PS knee and 5 knees were
Introduction. Femoral periprosthetic fractures above TKA are commonly treated with retrograde intramedullary nailing (IMN). This study determined if TKA design and liner type affect the minimum knee flexion required for retrograde nailing through a TKA. Methods. Twelve cadaveric specimens were prepared for six single radius (SR) TKAs and six asymmetric medial pivot (MP) TKAs. Trials with 9mm polyethylene liners were tested with cruciate retaining (CR), cruciate substituting (CS) and posterior stabilizing (PS) types. The knee was extended to identify the minimum knee flexion required to allow safe passage of the opening reamer while maintaining an optimal fluoroscopic starting point for retrograde nailing. Furthermore, the angle of axis deviation between the reamer and the femoral shaft was calculated from fluoroscopic images. Results. In all specimens, the reamer entry point was posterior to Blumensaat's line. In the SR TKA, the average flexion required was 70, 71 and 82 degrees for CR, CS and PS respectively. The required flexion in PS was significantly greater than the other designs (p=0.03). In the MP TKA, the average flexion required was 74, 84 and 123 degrees for CR, CS and PS respectively. The required flexion was significantly greater in CS and PS designs (p<0.0001). Femoral component size did not affect the minimum flexion required. Furthermore, the entry reamer required 9.2 (SR) and 12.5 (MP) degrees of posterior axis deviation from the femur. Conclusions. Our study illustrates four novel factors to consider when performing retrograde nailing through TKA. First, significant knee flexion is required to obtain an ideal radiographic starting point when retaining the liner. Second,
Aims. Total knee arthroplasty (TKA) using functional alignment aims to implant the components with minimal compromise of the soft-tissue envelope by restoring the plane and obliquity of the non-arthritic joint. The objective of this study was to determine the effect of TKA with functional alignment on mediolateral soft-tissue balance as assessed using intraoperative sensor-guided technology. Methods. This prospective study included 30 consecutive patients undergoing robotic-assisted TKA using the Stryker
INTRODUCTION. Applying the proper amount of tension to knees collateral ligaments during surgery is a prerequisite to achieve optimal performance after TKA. It must be taken into account that lower values of ligament tension could lead to an instable joint while higher values could induce over-tensioning thus leading to problems at later follow-up: a “functional stability” must then be defined and achieved to guarantee the best results. In this study, an experimental cadaveric activity was performed to measure the minimum tension required to achieve functional stability in the knee joint. METHODS. Ten cadaveric knee specimens were investigated; each femur and tibia was fixed with polyurethane foam in specific designed 3D-printed fixtures and clamped to a loading frame. A constant displacement rate of 0.05 mm/s was applied to the femoral clamp in order to achieve joint stability and the relative force was measured by the machine: the lowest force guaranteeing joint stability was then determined to be the one corresponding to the slope change in the force/displacement curve, representing the activation of the elastic region of both collateral ligaments. The force span between the slack region and the found point was considered to be the tension required to reach the functional stability of the joint. This methodology was applied on intact knee, after ACL-resection and after further PCL-resection in order to simulate the knee behavior in CR and
Introduction. The Flexible Nichidai Knee (FNK) System (Nakashima Medical, Japan) was designed to fit Asian knees. Especially, the posterior stabilized(PS) prosthesis was designed as semi-constrained posterior stabilized system that had a large tibial post and femoral articulation. We hypothesized that the semi-constrained
Aim: To examine the flexion stability of posterior stabilised (PS) vs deep dished (DD) tibial inserts, in PCL sacrificing total knee arthroplasty using posterior stress radiography. Methods: A simple jig was designed to allow kneeling posterior stress radiographs (at 90 degrees flexion) to be taken. This method was used to take pre and post-operative radiographs in 36 knees undergoing primary arthroplasty with PCL resection (26 DD and 10 PS implants). Sagittal plane tibial translation was measured. Results: The DD inserts all showed posterior displacement (mean: −5.1 mm, range: −2 to −12mm). The
Patellofemoral complaints are the common and nagging problem after total knee arthroplasty. Crepitus occurs in 5% to over 20% of knee arthroplasty procedures depending on the type of implant chosen. It is caused by periarticular scar formation with microscopic and gross findings indicating inflammatory fibrous hyperplasia. Crepitus if often asymptomatic and not painful, but in some cases can cause pain. Patella “Clunk Syndrome” is less common and represents when the peripatella scarring is abundant and forms a nodule which impinges and “catches” on the implant's intercondylar notch. Patella Clunk was more common with early PS designs due to short trochlear grooves with sharp transition into the intercondylar notch. Clunks are very infrequent with modern
Introduction & aims. Patient specific instrumentation (PSI) is a useful tool to execute pre-operatively planned surgical cuts and reduce the number of trays in surgery. Debate currently exists around improved accuracy, efficacy and patient outcomes when using PSI cutting guides compared to conventional instruments. Unicompartmental Knee Arthroplasty (UKA) revision to Total Knee Arthroplasty (TKA) represents a complex scenario in which traditional bone landmarks, and patient specific axes that are routinely utilised for component placement may no longer be easily identifiable with either conventional instruments or navigation. PSI guides are uniquely placed to solve this issue by allowing detailed analysis of the patient morphology outside the operating theatre. Here we present a tibia and femur PSI guide for TKA on patients with UKA. Method. Patients undergoing pre-operative planning received a full leg pass CT scan. Images are then segmented and landmarked to generate a patient specific model of the knee. The surgical cuts are planned according to surgeon preference. PSI guide models are planned to give the desired cut, then 3D printed and provided along with a bone model in surgery. PSI-bone and PSI-UKA contact areas are modified to fit the patient anatomy and allow safe placement and removal. The PSI-UKA contact area on the tibia is defined across the UKA tibial tray after the insert has been removed. Further contact is planned on the tibial eminence if it can be accurately segmented in the CT and the anterior superior tibia on the contralateral compartment, see example guide in Figure 1. Contact area on the femur is defined on the superior trochlear groove, native condyle, femur centre and femoral UKA component if it can be accurately segmented in the CT. Surgery was performed with a target of mechanical alignment using OMNI APEX
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 alignment, across different activities. LifeModeler KneeSIM software was used to calculate tibial post contact forces for four contemporary
Many patients who undergo a total knee arthroplasty (TKA) wish to return to a more active lifestyle. The implant must be able to restore adequate muscle strength and function. However, this may not be a reality for some patients as quadriceps and hamstrings muscle activity may remain impaired following surgery. The purpose of this study was to compare muscle activity between patients implanted with a medial pivot (MP) or posterior stabilized (PS) implant and controls (CTRL) during ramp walking tasks. Fifteen patients were assigned to either a MP (n=9) or PS (n=6) TKA operated by the same surgeon. Nine months following surgery, the 15 patients along with nine CTRL patients completed motion and EMG analysis during level, ramp ascent & descent walking tasks. Wireless EMG electrodes were placed on six muscles: vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), semimembranosus (SM) muscles, gastrocnemius medial head (GM), and gastrocnemius lateral head (GL). Participants completed three trials of each condition. EMG data were processed for an entire gait cycle of the operated limb in the TKA groups, and for the dominant limb in the CTRL group. The maximum muscle activity achieved with each muscle during the level trial was used to normalize the ramp trials. The onset and offset of each muscle was determined using the approximated generalized likelihood ratio. Peak muscle activity (PeakLE), total muscle activity (iEMG), and muscle onsets/offsets were determined for each muscle for the ramp ascent and descent trials. Non-parametric Kruskal Wallace tests were used to test for statistical significance between groups with α=0.05. During the ramp up task, both MP and PS groups had significantly greater PeakLE and iEMG for the hamstring muscles compared to the CTRL, whereas the PS group had significantly greater PeakLE compared with the MP group for the SM muscle. During the ramp down task, both MP and PS groups had significantly greater PeakLE and iEMG for the SM and GL muscles compared to the CTRL. The PS group also had significantly greater iEMG for the BF and VM muscles compared to the CTRL. The MP group had a significantly earlier offset for the SM muscle compared to the CTRL. Stability in a cruciate removing TKA is partially controlled by the prosthetic design. During the ramp up task, the TKA groups compensated the tibial anterior translation by activating their hamstrings more and for a longer duration. The MP group required less hamstrings activation than the PS group. During the ramp down task, TKA patients stiffened their knee in order to stabilize the joint. The quadriceps, hamstrings and GL muscle were activated more and for a longer duration than the CTRL group to protect the tibial posterior translation. The PS group required greater BF and VM iEMG than the MP group. Even if surgery reduced pain, differences in muscle activity exist between TKA patients and healthy controls. The prosthetic design provides some stability to the knee, and the MP implant required less muscle activation than the
The mean age of patients undergoing total knee arthroplasty (TKA) has reduced with time. Younger patients have increased expectations following TKA. Aseptic loosening of the tibial component is the most common cause of failure of TKA in the UK. Interest in cementless TKA has re-emerged due to its encouraging results in the younger patient population. We review a large series of tantalum trabecular metal cementless implants in patients who are at the highest risk of revision surgery. A total of 454 consecutive patients who underwent cementless TKA between August 2004 and December 2021 were reviewed. The mean follow-up was ten years. Plain radiographs were analyzed for radiolucent lines. Patients who underwent revision TKA were recorded, and the cause for revision was determined. Data from the National Joint Registry for England, Wales, Northern Island, the Isle of Man and the States of Guernsey (NJR) were compared with our series.Aims
Methods
Introduction. John Insall described medial release to balance the varus knee; the release he described included releasing the superficial MCL in severe varus cases. However, this release can create instability in the knee. Furthermore, this conventional wisdom does not correct the actual pathology which normally exists at the joint line, and instead it focuses on the distal end of the ligament where there is no pathology. We have established a new protocol consisting of 5 steps to balance the varus knee without releasing the superficial MCL and we tried this algorithm on a series of 115 patients with varus deformity and compared it to the outcome with a similar group that we have performed earlier using the traditional Insall technique. Material and method. 115 TKR were performed by the same surgeon using Zimmer Persona implant in varus arthritic knees. The deformities ranged from 15 to 35 degrees. First, the bony resection was made using Persona instrumentation as recommended by the manufacturer. The sequential balancing was divided into 5 steps (we will show a short video demonstrating the surgical techniques for each step) as follows:. Step 1: Releasing of deep MCL Step 2: Excising of osteophyte. Step 3: Excising of scarred tissue in the posteromedial corner soft phytes Step 4: Excision of the posteromedial capsule in case of flexion contracture Step 5: Releasing the semi-membranous (in gross deformity). We used soft tissue tensioner to balance the medial and lateral gaps. When the gaps are balanced at early step, there was no need to carry on the other steps. We used only primary implant and we did not have to use any constrained implant. We have compared this group with a similar group matched for deformity from previous 2 years where the conventional medial release as described by Insall. Results. We could balance all knees without releasing the superficial MCL ligament as follows:. -In[H1] 31 cases, we were able to balance the knees performing step 1 and step 2 only. -In 35 cases, we had to do step three in addition to 1 and 2 to achieve balance of cases. -In 25 cases, we performed step 4- those cases had pre-operative flexion contracture. -We had to proceed to step 5 only in 14 cases. These patients had the worst deformity in the group. We have used primary TKR in all cases; in 83 cases, we used a CR implant and in the rest, we used
The April 2023 Knee Roundup360 looks at: Does bariatric surgery reduce complications after total knee arthroplasty?; Mid-flexion stability in total knee arthroplasties implanted with kinematic alignment: posterior-stabilized versus medial-stabilized implants; Inflammatory response in robotic-arm-assisted versus conventional jig-based total knee arthroplasty; Journey II bicruciate stabilized (JII-BCS) and GENESIS II total knee arthroplasty: the CAPAbility, blinded, randomized controlled trial; Lifetime risk of revision and patient factors; Platelet-rich plasma use for hip and knee osteoarthritis in the USA; Where have the knee revisions gone?; Tibial component rotation in total knee arthroplasty: CT-based study of 1,351 tibiae.
Obtaining solid implant fixation is crucial in revision total knee arthroplasty (rTKA) to avoid aseptic loosening, a major reason for re-revision. This study aims to validate a novel grading system that quantifies implant fixation across three anatomical zones (epiphysis, metaphysis, diaphysis). Based on pre-, intra-, and postoperative assessments, the novel grading system allocates a quantitative score (0, 0.5, or 1 point) for the quality of fixation achieved in each anatomical zone. The criteria used by the algorithm to assign the score include the bone quality, the size of the bone defect, and the type of fixation used. A consecutive cohort of 245 patients undergoing rTKA from 2012 to 2018 were evaluated using the current novel scoring system and followed prospectively. In addition, 100 first-time revision cases were assessed radiologically from the original cohort and graded by three observers to evaluate the intra- and inter-rater reliability of the novel radiological grading system.Aims
Methods
The most recent Australian registry has a database of 547,407 knee arthroplasties, having added over 52,000 in 2016. Total knee arthroplasties (TKA) comprise 83.8%, revisions (RevTKA) 8.1% and “partials of all types” 8.1%. Since 2003, the percent of TKA has increased from 76.7%, RevTKA has stayed stable and partial replacements have declined from 14.5%. In the last year, however, TKA declined slightly. There is a slightly higher percentage of women (56.1%) undergoing TKA and this has remained very stable since 2003. Revision rates are slightly higher for men. Percentages of the youngest (<55) and oldest (>85) are small and stable. The 75–84 year olds have declined as 55–74 year olds have increased. This represents a gradual shift to earlier TKA surgery. More patella are resurfaced and this is a gradual trend with a cross over in 2010 when half were resurfaced. Computer navigation is progressively more popular and now accounts for almost 30% of cases. Cement fixation is also increasing and accounts for about 65% of cases. Crosslinked polyethylene is gradually replacing non crosslinked and in 2014 was used in 50% of cases. Revisions are performed most commonly for loosening and infection. Revision rates correlate directly with age. Loosening is the most common indication for revision in both genders, but males have a distinctly higher revision rate due to infection. Revision rates are slightly higher in all forms of mobile bearing than fixed bearing. Minimally constrained (cruciate retaining) devices are used in the majority of TKAs. Posterior stabilised implants are in slight decline, having peaked in about 2008–2010. Minimally constrained implants are in slight decline as medial pivot/medial congruent devices have been used more frequently. Revision rates are similar amongst all three