IC3D Classification of Corneal Dystrophies-Edition 3.

PURPOSE: The International Committee for the Classification of Corneal Dystrophies (IC3D) was created in 2005 to develop a new classification system integrating current information on phenotype, histopathology, and genetic analysis. This update is the third edition of the IC3D nomenclature. METHODS: Peer-reviewed publications from 2014 to 2023 were evaluated. The new information was used to update the anatomic classification and each of the 22 standardized templates including the level of evidence for being a corneal dystrophy [from category 1 (most evidence) to category 4 (least evidence)]. RESULTS: Epithelial recurrent erosion dystrophies now include epithelial recurrent erosion dystrophy, category 1 ( COL17A1 mutations, chromosome 10). Signs and symptoms are similar to Franceschetti corneal dystrophy, dystrophia Smolandiensis, and dystrophia Helsinglandica, category 4. Lisch epithelial corneal dystrophy, previously reported as X-linked, has been discovered to be autosomal dominant ( MCOLN1 mutations, chromosome 19). Classic lattice corneal dystrophy (LCD) results from TGFBI R124C mutation. The LCD variant group has over 80 dystrophies with non-R124C TGFBI mutations, amyloid deposition, and often similar phenotypes to classic LCD. We propose a new nomenclature for specific LCD pathogenic variants by appending the mutation using 1-letter amino acid abbreviations to LCD. Pre-Descemet corneal dystrophies include category 1, autosomal dominant, punctiform and polychromatic pre-Descemet corneal dystrophy (PPPCD) ( PRDX3 mutations, chromosome 10). Typically asymptomatic, it can be distinguished phenotypically from pre-Descemet corneal dystrophy, category 4. We include a corneal dystrophy management table. CONCLUSIONS: The IC3D third edition provides a current summary of corneal dystrophy information. The article is available online at https://corneasociety.org/publications/ic3d .

Incidence of Total Blindness After Central Retinal Artery Occlusion With Ocular Neovascularization.

Purpose: To determine the time-based incidence of total blindness after central retinal artery occlusion (CRAO) with secondary ocular neovascularization (ONV). Methods: In this retrospective cohort study, electronic records were queried using ICD-9 and ICD-10 codes to identify patients with secondary ONV post-CRAO. Patients with possible alternative ONV etiologies, previous panretinal photocoagulation (PRP), and/or previous antivascular endothelial growth factor (anti-VEGF) therapy were excluded. Clinical data included demographics, medical comorbidities, ONV manifestations, medical/surgical management, and best-corrected visual acuity (BCVA). Kaplan-Meier analysis was performed with total blindness (defined as a BCVA of no light perception) as the outcome of interest. Results: Of 345 eyes with CRAO, 34 met the inclusion criteria with a mean (±SD) follow-up of 22.0 ± 26.2 months. ONV management included PRP (70.6%), glaucoma drainage implant surgery or transscleral cyclophotocoagulation (32.4%), and intravitreal anti-VEGF therapy (mean 2.8 ± 5.6 injections per patient). The cumulative incidence of total blindness was 49.4% (95% confidence interval, 27.2%-71.6%) at 24 months, with 53.3% of cases occurring within 4 months of ONV onset. Conclusions: Post-CRAO ONV is associated with a high risk for progression from severe vision loss to total blindness. Neovascular glaucoma can present up to 4 months after CRAO, challenging the paradigm of "30-day-glaucoma." Routine gonioscopy should extend through this period, while glaucoma surgery can delay further vision loss. These findings can be used to counsel patients on the importance of follow-up adherence.

Primary ductal adenocarcinoma of the lacrimal gland with sarcomatoid differentiation: case report and genomic analysis.

We describe a case of primary ductal adenocarcinoma of the lacrimal gland with novel histopathological characteristics corresponding to a biphasic growth course and provide a comprehensive genomic profile of this malignancy. A 39-year-old male with a history of slowly progressive unilateral proptosis and hypoglobus presented after 1 month of hyperacute exacerbation. Orbital imaging revealed a superior mass with osseous erosion. The patient underwent orbital exploration and excisional biopsy via lateral orbitotomy. Histopathology demonstrated high-grade adenocarcinoma with a well-differentiated glandular component alongside a poorly differentiated sarcomatoid region. The glandular section was immunopositive for Her-2, CK7, GATA3, and androgen receptor. Tumor recurrence necessitated en-bloc exenteration with dural resection alongside adjuvant radiotherapy and chemotherapy. This represents the first report of sarcomatoid differentiation in primary ductal adenocarcinoma of the lacrimal gland, which may incite hyperacute progression. Conversely, GATA3 immunopositivity may correlate with indolent growth. Genomic variants such as SEMA3C represent potential therapeutic targets for this condition.

Subretinal Abscess Complicated by Post-infectious Retinal Vasculitis Following Strabismus Surgery.

An 8-year-old girl presented with a subretinal abscess after strabismus surgery. This was treated successfully with medial rectus suture removal, pars plana vitrectomy, intravitreal antibiotics, and intravenous antibiotics. Recovery was complicated by acute post-infectious retinal vasculitis after tapering high-dose corticosteroids, requiring an extended corticosteroid regimen over 2 months until resolution. [J Pediatr Ophthalmol Strabismus. 2023;60(3):e26-e30.].

Central Retinal Artery Occlusion with Concomitant Intracranial Hemorrhage Secondary to Streptococcus Gordonii Endocarditis.

Purpose: To report a case of central retinal artery occlusion (CRAO) associated with subacute Streptococcus gordonii endocarditis secondary to a dental infection. Observations. A 27-year-old male presented with acute monocular vision loss in the setting of a stroke and seizure. A fundus exam revealed macular whitening and a cherry-red spot. Edema of the inner retinal layers was confirmed on macular optical coherence tomography, consistent with CRAO. Initial imaging (carotid Doppler, EKG, and transthoracic echocardiography) and a comprehensive laboratory workup did not reveal an etiology for the stroke or vision loss. Brain magnetic resonance imaging showed T1 hyperintensity with surrounding edema, which prompted a workup for possible septic emboli versus occult malignancy. Subsequent blood cultures led to the detection and diagnosis of Streptococcus gordonii endocarditis. It was subsequently revealed that the patient had self-extracted his molar two months prior to the onset of symptoms. Conclusions: Endocarditis has been associated with Roth spots and inflammatory findings in the posterior segment. However, CRAO caused by vegetal septic embolism is rare. To our knowledge, this represents the first reported case of endocarditic CRAO with Streptococcus gordonii confirmed as the causative microbe. Retinal vascular occlusion in a young patient with no distinct risk factors should prompt a comprehensive dental history and infectious workup, with consideration given to early transesophageal echocardiography.

Economic Evaluation of Artificial Intelligence Systems Versus Manual Screening for Diabetic Retinopathy in the United States.

BACKGROUND: The objective of this economic modeling study was to compare the cost effectiveness of fully automated retinal image screening (FARIS) to the current practice of universal ophthalmologist referral for diabetic retinopathy in the United States (US) health care system. METHODS: A Markov decision-analytic model was used to compare the automated versus manual screening and management pathway for diabetic patients with unknown retinopathy status. Costs (in 2021 US dollars), quality-adjusted life year (QALY) gains, and incremental cost-effectiveness ratios were calculated. Sensitivity analysis was performed against a $50,000/QALY willingness-to-pay threshold. RESULTS: FARIS was the dominant screening strategy, demonstrating cost savings of 18.8% at 5 years with equivalent net QALY gains to manual screening. Cost-effectiveness status was dependent on FARIS detection specificity, with a threshold value of 54.8%. CONCLUSION: Artificial intelligence-based screening represents an economically advantageous screening modality for diabetic retinopathy in the US, offering equivalent long-term utility with significant potential cost savings. [Ophthalmic Surg Lasers Imaging Retina 2023;54:272-280.].

Reverse Total Shoulder Arthroplasty: Technique, Decision-Making and Exposure Tips.

PURPOSE OF REVIEW: The goal of this review is to introduce surgical decision-making pearls for reverse shoulder arthroplasty and describe optimization of surgical exposure for reverse shoulder arthroplasty. RECENT FINDINGS: While the technology of reverse shoulder replacement and the associated prosthetic options have expanded, the principles involved in successfully exposing the humerus and glenoid in arthroplasty remain the same. Reverse shoulder replacement should be considered in arthroplasty situations with rotator cuff disease, deformity, bone loss, and instability as part of the diagnosis. Optimal exposure in reverse shoulder arthroplasty can be obtained by (1) releasing deltoid adhesions, (2) removal of humeral osteophytes, (3) generous humeral head cuts, (4) thorough humeral and glenoid capsular release and (5) optimal glenoid retractor placement. Neuromuscular paralysis can also aid glenoid exposure.

Radiographic and Clinical Outcomes of Periprosthetic Distal Femur Fractures Treated With Open Reduction Internal Fixation.

OBJECTIVES: To report outcomes and complications of periprosthetic distal femur fractures (PPDFF) treated with open reduction internal fixation (ORIF) using a plate construct, with or without endosteal augmentation. DESIGN: Retrospective Case Series. SETTING: One Level I trauma center and one tertiary care hospital. PATIENTS/PARTICIPANTS: Forty patients with PPDFFs, treated by 3 surgeons, were identified using an institutional trauma registry. Thirty-two patients with 12 months of clinical and radiographic follow-up were included, and 8 patients were lost to follow-up before 12 months. INTERVENTION: All patients underwent ORIF of the PPDFF with lateral locked plating, and 11 received additional endosteal augmentation using allograft fibula. RESULTS: Thirty-two patients were available for the final follow-up. Ninety-four percent of patients achieved union at an average of 6.5 months postoperatively. Twenty-one percent of patients underwent subsequent surgery, with more than half of those being for removal of implants. Anatomic limb alignment was achieved in all cases (no malunions). Almost half of the patients required assistive devices for ambulation in the long term. CONCLUSIONS: ORIF of PPDFF with direct visualization using periarticular locking plates ± endosteal strut allograft resulted in a 94% union rate and no deep infections. There was no difference in outcomes between groups treated with or without additional endosteal fibular allograft. However, these are catastrophic injuries in frail patients, and 20% of patients either died or were lost to follow-up, and almost half required an assistive device for ambulation after surgery despite restoration of limb alignment. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Annual revision rates of partial versus total knee arthroplasty: A comparative meta-analysis.

BACKGROUND: Utilization of unicompartmental knee arthroplasty (UKA) and patellofemoral arthroplasty (PFA) as alternatives to total knee arthroplasty (TKA) for unicompartmental knee osteoarthritis (OA) has increased. However, no single resource consolidates survivorship data between TKA and partial resurfacing options for each variant of unicompartmental OA. This meta-analysis compared survivorship between TKA and medial UKA (MUKA), lateral UKA (LUKA) and PFA using annual revision rate as a standardized metric. METHODS: A systematic literature search was performed for studies quantifying TKA, MUKA, LUKA and/or PFA implant survivorship. Studies were classified by evidence level and assessed for bias using the MINORS and PEDro instruments. Annual revision rates were calculated for each arthroplasty procedure as percentages/observed component-year, based on a Poisson-normal model with random effects using the R-statistical software package. RESULTS: One hundred and twenty-four studies (113 cohort and 11 registry-based studies) met inclusion/exclusion criteria, providing data for 374,934 arthroplasties and 14,991 revisions. The overall evidence level was low, with 96.7% of studies classified as level III-IV. Annual revision rates were lowest for TKA (0.49%, CI 0.41 to 0.58), followed by MUKA (1.07%, CI 0.87 to 1.31), LUKA (1.13%, CI 0.69 to 1.83) and PFA (1.75%, CI 1.19 to 2.57). No difference was detected between revision rates for MUKA and LUKA (p=0.222). CONCLUSIONS: Revisions of MUKA, LUKA and PFA occur at an annual rate of 2.18, 2.31 and 3.57-fold that of TKA, respectively. These estimates may be used to inform clinical decision-making, guide patient expectations and evaluate the cost-effectiveness of total versus partial knee replacement in the setting of unicompartmental OA.

The Role of Patient Characteristics on the Choice of Unicompartmental versus Total Knee Arthroplasty in Patients With Medial Osteoarthritis.

BACKGROUND: Medial unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are both viable treatment options for medial osteoarthritis (OA). However, it remains unclear when to choose for which arthroplasty treatment. Goals of this study were therefore to (1) compare outcomes after both treatments and (2) assess which treatment has superior outcomes in different patient subgroups. METHODS: In this retrospective cohort study, 166 patients received the RESTORIS MCK Medial UKA and 63 patients the Vanguard TKA and were radiographically matched on isolated medial OA. Western Ontario and McMaster Universities Arthritis Index scores were collected preoperatively and postoperatively (mean: 3.0 years, range: 2.0-5.0 years). RESULTS: Preoperatively, no differences were observed, but medial UKA patients reported better functional outcomes than TKA (89.7 ± 13.6 vs 81.2 ± 18.0, P = .001) at follow-up.Better functional outcomes were noted after medial UKA in patients younger than age 70 years (89.5 ± 14.2 vs 78.6 ± 20.0, P = .001), with body mass index below 30 (90.3 ± 11.4 vs 83.6 ± 14.9, P = .005), with body mass index above 30 (88.3 ± 17.5 vs 78.8 ± 21.0, P = .034) and in females (90.6 ± 11.0 vs 78.1 ± 19.4, P = .001) when compared with TKA. No differences were found in males and older patients between both arthroplasties. CONCLUSION: Superior functional outcomes were noted after medial UKA over TKA in patients presenting with medial OA with these prostheses. Subgroup analyses suggest that medial UKA is the preferred treatment in younger patients and females while no differences were noted in older patients and males after medial UKA and TKA. This might help the orthopedic surgeon in individualizing arthroplasty treatment for patients with medial OA.

Establishing Age-Specific Cost-Effective Annual Revision Rates for Unicompartmental Knee Arthroplasty: A Meta-Analysis.

BACKGROUND: Improved survivorship has contributed to the increased use of unicompartmental knee arthroplasty (UKA) as an alternative to total knee arthroplasty (TKA) for unicompartmental knee osteoarthritis. However, heterogeneity among cost-effectiveness analysis studies comparing UKA to TKA has prevented the derivation of discrete implant survivorship targets. The aim of this meta-analysis was to determine the age-stratified annual revision rate (ARR) threshold for UKA to become consistently cost-effective for unicompartmental knee osteoarthritis. METHODS: A systematic search was performed for cost-effectiveness analysis studies of UKA vs TKA. Selected publications were rated by evidence level and assessed for methodological quality. Target UKA survivorship values determined by sensitivity analysis were retrieved, converted to ARR, and combined by age category (<65, 65-74, and ≥75 years) to estimate age-specific cost-effectiveness thresholds. RESULTS: Four studies met all inclusion criteria. All publications were evidence level I-B, with high methodological quality. Combined data indicated median threshold cost-effective ARR of 1.471% (interquartile range [IQR], 1.415-1.833; age <65), 1.135% (IQR, 1.011-1.260; age 65-74), and 1.760% (IQR, 1.660-2.880; age ≥75). Current revision rates are already below the cost-effective threshold for patients aged ≥75, but exceed recommended values in younger patients. CONCLUSION: The findings indicate that implant survivorship is a limiting factor toward achieving cost-effective UKA in patients aged <65. Strategies to improve UKA survivorship, such as shifting procedures to high-volume centers, may render UKA cost-effective in younger patients. This presents an opportunity for resource reallocation within health systems to achieve cost-effective utilization of UKA across a broader population segment.

Outcomes of cementless unicompartmental and total knee arthroplasty: A systematic review.

BACKGROUND: Aseptic loosening is a common failure mode in cemented unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). This led to the development of cementless designs but the historical outcomes were poor. Recent developments in cementless designs have improved outcomes, but the current status is unknown. Therefore, a systematic review was performed to assess recent outcomes of cementless knee arthroplasty. METHODS: A search was performed using PubMed, Embase and Cochrane systems and national registries for studies reporting outcomes since 2005. Fifty-two cohort studies and four registries reported survivorship, failure modes or functional outcomes of cementless UKA and TKA. RESULTS: Nine level I studies, six level II studies, three level III studies, 34 level IV studies and four registries were included. Three hundred eighteen failures in 10,309 cementless TKA procedures and 62 failures in 2218 cementless UKA procedures resulted in extrapolated five-year, 10-year and 15-year survivorship of cementless TKAs of 97.7%, 95.4% and 93.0%, respectively, and cementless UKA of 96.4%, 92.9% and 89.3%, respectively. Aseptic loosening was more common in cementless TKA (25%) when compared to UKA (13%). Functional outcomes of cementless TKA and UKA were excellent with 84.3% and 84.5% of the maximum possible scores, respectively. CONCLUSIONS: This systematic review showed that good to excellent extrapolated survivorship and functional outcomes are seen following modern cementless UKA and TKA, with a low incidence of aseptic loosening following cementless UKA. LEVEL OF EVIDENCE: Level IV.

Different optimal alignment but equivalent functional outcomes in medial and lateral unicompartmental knee arthroplasty.

INTRODUCTION: Several differences in kinematics, functional outcomes and alignment exist between medial and lateral unicompartmental knee arthroplasty (UKA). Therefore, the purpose of this study was (1) to compare functional outcomes between both procedures with the hypothesis that both have equivalent outcomes and (2) to assess the role of preoperative and postoperative alignment on functional outcomes in both procedures. METHODS: Patients who underwent UKA were included when overall function - using Western Ontario and McMaster Universities Arthritis (WOMAC) score - and joint awareness - using Forgotten Joint Score (FJS) - were available preoperatively and at minimum two-year follow-up. A total of 143 medial UKA and 36 lateral UKA patients reported outcomes at mean 2.4-years follow-up (range 2.0 to 5.0year). RESULTS: Preoperatively and postoperatively, no differences were seen between medial and lateral UKA in overall function (89.8±11.7 vs. 90.2±12.4, respectively, p=0.855) and joint awareness (71.2±24.5 vs. 70.9±28.2, respectively, p=0.956). With neutral postoperative alignment (-1° to three degrees), less joint awareness was noted following medial UKA than lateral UKA (72.6±22.6 vs. 55.3±28.5, p=0.024). With undercorrection (three degrees to seven degrees), however, following lateral UKA less joint awareness (85.3±19.5 vs. 68.2±26.8, p=0.020) and better functional outcomes (96.0±5.4 vs. 88.5±11.6, p=0.001) were noted than medial UKA. CONCLUSION: Equivalent functional outcomes were noted between medial and lateral UKA at short-term follow-up but different optimal alignment angles seem to exist for both procedures. LEVEL OF EVIDENCE: Level III therapeutic study.

Current state of computer navigation and robotics in unicompartmental and total knee arthroplasty: a systematic review with meta-analysis.

Recently, there is a growing interest in surgical variables that are intraoperatively controlled by orthopaedic surgeons, including lower leg alignment, component positioning and soft tissues balancing. Since more tight control over these factors is associated with improved outcomes of unicompartmental knee arthroplasty and total knee arthroplasty (TKA), several computer navigation and robotic-assisted systems have been developed. Although mechanical axis accuracy and component positioning have been shown to improve with computer navigation, no superiority in functional outcomes has yet been shown. This could be explained by the fact that many differences exist between the number and type of surgical variables these systems control. Most systems control lower leg alignment and component positioning, while some in addition control soft tissue balancing. Finally, robotic-assisted systems have the additional advantage of improving surgical precision. A systematic search in PubMed, Embase and Cochrane Library resulted in 40 comparative studies and three registries on computer navigation reporting outcomes of 474,197 patients, and 21 basic science and clinical studies on robotic-assisted knee arthroplasty. Twenty-eight of these comparative computer navigation studies reported Knee Society Total scores in 3504 patients. Stratifying by type of surgical variables, no significant differences were noted in outcomes between surgery with computer-navigated TKA controlling for alignment and component positioning versus conventional TKA (p = 0.63). However, significantly better outcomes were noted following computer-navigated TKA that also controlled for soft tissue balancing versus conventional TKA (mean difference 4.84, 95 % Confidence Interval 1.61, 8.07, p = 0.003). A literature review of robotic systems showed that these systems can, similarly to computer navigation, reliably improve lower leg alignment, component positioning and soft tissues balancing. Furthermore, two studies comparing robotic-assisted with computer-navigated surgery reported superiority of robotic-assisted surgery in controlling these factors. Manually controlling all these surgical variables can be difficult for the orthopaedic surgeon. Findings in this study suggest that computer navigation or robotic assistance may help managing these multiple variables and could improve outcomes. Future studies assessing the role of soft tissue balancing in knee arthroplasty and long-term follow-up studies assessing the role of computer-navigated and robotic-assisted knee arthroplasty are needed.

Robotic-Assisted Knee Arthroplasty: An Overview.

Unicompartmental knee arthroplasty and total knee arthroplasty are reliable treatment options for osteoarthritis. In order to improve survivorship rates, variables that are intraoperatively controlled by the orthopedic surgeon are being evaluated. These variables include lower leg alignment, soft tissue balance, joint line maintenance, and tibial and femoral component alignment, size, and fixation methods. Since tighter control of these factors is associated with improved outcomes of knee arthroplasty, several computer-assisted surgery systems have been developed. These systems differ in the number and type of variables they control. Robotic-assisted systems control these aforementioned variables and, in addition, aim to improve the surgical precision of the procedure. Robotic-assisted systems are active, semi-active, or passive, depending on how independently the systems perform maneuvers. Reviewing the robotic-assisted knee arthroplasty systems, it becomes clear that these systems can accurately and reliably control the aforementioned variables. Moreover, these systems are more accurate and reliable in controlling these variables when compared to the current gold standard of conventional manual surgery. At present, few studies have assessed the survivorship and functional outcomes of robotic-assisted surgery, and no sufficiently powered studies were identified that compared survivorship or functional outcomes between robotic-assisted and conventional knee arthroplasty. Although preliminary outcomes of robotic-assisted surgery look promising, more studies are necessary to assess if the increased accuracy and reliability in controlling the surgical variables leads to better outcomes of robotic-assisted knee arthroplasty.

The ACL Graft Has Different Cross-sectional Dimensions Compared With the Native ACL: Implications for Graft Impingement.

BACKGROUND: Impingement of anterior cruciate ligament (ACL) grafts against the femoral notch and the posterior cruciate ligament (PCL) is thought to be influenced primarily by tunnel position and graft orientation. Recent data have implied that the native ACL is ribbon-shaped. PURPOSE: To evaluate the 3-dimensional shape and cross-sectional area of the native ACL versus the ACL graft and to compare the degree of impingement against the femoral notch and PCL. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Bilateral knee magnetic resonance images were analyzed for 27 patients with unilateral bone-patellar tendon-bone (BPTB) ACL reconstruction performed via transtibial or anteromedial portal femoral tunneling techniques. Three-dimensional models of the ACL, PCL, femur, and tibia were digitally rendered. The cross-sectional area and dimensions of the native ACL and the reconstructed graft were determined at 3 equally spaced locations and compared via Wilcoxon-Mann-Whitney and Kruskal-Wallis tests. In addition, impingement of the ACL on the PCL and femoral notch was graded in 3 groups. Chi-square or Fisher exact tests were used to compare the proportional differences of impingement of the native and reconstructed ACL on the PCL and femoral notch, respectively. All analyses were performed using 2-sided hypothesis testing, with statistical significance at P < .05. RESULTS: Cross-sectional areas at all 3 points on the ACL graft were significantly greater than those of the native ACL (P < .001). The long- to short-axis ratio for the native ACL was significantly greater at each location compared with the corresponding locations along the ACL graft (P < .001), implying that the native ACL is "flatter" than is an ACL graft. There were 19 operated knees (70%) with contact or impingement between the ACL graft and the femoral notch compared with zero knees with a native ACL (P < .001). In addition, 22 operated knees (81%) showed contact or impingement between the ACL graft and the PCL, compared with 7 knees (26%) with a native ACL (P < .001). No significant differences in impingement frequency were noted between the transtibial and anteromedial tunneling techniques for ACL graft specimens (P > .05). CONCLUSION: Native ACLs have a smaller cross-sectional area, are "flatter," and experience less incidence of impingement compared with anatomically placed BPTB ACL grafts.

The Role of Preoperative Patient Characteristics on Outcomes of Unicompartmental Knee Arthroplasty: A Meta-Analysis Critique.

BACKGROUND: In 1989, Kozinn and Scott introduced strict exclusion criteria for unicompartmental knee arthroplasty (UKA). Because outcomes have improved with modern techniques and implants, these criteria have now been challenged. Therefore, the goal was to assess the role of these criteria on (1) functional outcomes and (2) revision rates of medial UKA. The hypothesis was that, with modern surgical techniques and implants, these traditional exclusion criteria are no longer strict contraindications for UKA. METHODS: Databases of PubMed, EMBASE, and Cochrane and annual registries were searched for studies comparing UKA results in subgroups: age (young vs old), gender (male vs female), body mass index (obese vs nonobese), present vs absent patellofemoral osteoarthritis, and intact vs deficient anterior cruciate ligament. RESULTS: Thirty-one comparative cohort studies (7 level II and 24 level III/IV studies) and 6 registries reported outcomes in 17,147 patients and revision rates in 285,472 patients. Females had inferior functional outcomes compared to males (odds ratio [OR], 4.03; 95% CI, 1.77-6.30). Furthermore, younger patients (in studies: OR, 1.52; 95% CI, 1.06-2.19; in registries: OR, 2.09; 95% CI, 1.70-2.57) and females (OR, 1.13; 95% CI, 1.06-1.21) had increased likelihood for revision. No increased likelihood for inferior outcomes or revisions was detected in patients with obesity, preoperative patellofemoral osteoarthritis, or anterior cruciate ligament deficiency. CONCLUSION: Findings of increased revision risk in younger patients and increased revision risk with inferior outcomes in females give a more nuanced perspective on historical criteria, such that surgical decision-making may be based on UKA outcome data for subgroups rather than strict exclusion criteria.

Comparative Fixation and Subsidence Profiles of Cementless Unicompartmental Knee Arthroplasty Implants.

BACKGROUND: Aseptic loosening is the primary cause of failure for both cemented and cementless unicondylar knee replacements (UKRs). Micromotion and subsidence of tibial baseplate are two causes of failure, due to poor fixation and misalignment, respectively. METHODS: Stair ascent activity profiles from Bergmann et al and Li et al were used. Biphasic Sawbones models were prepared according to the surgical techniques of traditional and novel cementless UKRs. Implants were tested for 10,000 cycles representing post-operative bone interdigitation period, and micromotion was observed using speckle pattern measurements, which demonstrated sufficient resolution. Additionally, the test method proposed by Liddle et al was used to measure subsidence with pressure sensors under increasingly lateralized loading. RESULTS: Mean displacement due to micromotion for mediolateral and anteroposterior plane was consistently greater for traditional cementless UKR. Mean displacement for axial micromotion was significantly higher for traditional UKR at the anterior aspect of the implant; however, values were lower for the medial periphery of the implant. Subsidence was significantly lower for the novel design with increasingly lateralized loading, and indentation was not observed on the test substrate, when compared to the traditional design. CONCLUSION: Our findings demonstrate that the novel cementless design is capable of fixation and elimination of subsidence in laboratory test settings. Both designs limit micromotion to below the established loosening micromotion value of 150 µm. The L-shaped keel design resists both micromotion and subsidence and may prevent failure modes that can lead to aseptic loosening for UKRs. These findings are highly relevant for clinical application.

Predictors of Subjective Outcome After Medial Unicompartmental Knee Arthroplasty.

BACKGROUND: Unexplainable pain after medial unicompartmental knee arthroplasty (UKA) remains a leading cause for revision surgery. Therefore, the aim of this study is to identify the patient-specific variables that may influence subjective outcomes after medial UKA to optimize results. METHODS: Retrospectively, we analyzed 104 consecutive medial UKA patients. The evaluated parameters consisted of age, body mass index, gender, preoperative radiographic severity of the various knee compartments, and preoperative and postoperative mechanical axis alignments. RESULTS: At an average of 2.3-year follow-up, our data demonstrate that body mass index, gender, and preoperative severity among the various knee compartments do not influence Western Ontario and McMaster Universities Arthritis Index (WOMAC) results. Preoperatively, patients aged <65 years had inferior WOMAC stiffness (4.6 vs 2.9, P = .001), pain (9.7 vs 7.6, P = .041), and total (37.2 vs 47.6, P = .028) scores vs patients aged ≥65 years. Postoperatively, only the difference on the WOMAC stiffness subscale remained significant between both age groups, in favor of patients aged ≥65 years (1.0 vs 1.5, P = .035). A postoperative varus mechanical axis alignment of 1°-4° correlated to significantly superior WOMAC pain (P = .03), function (P = .04), and total (P = .04) scores compared to a varus of ≤1° or ≥4°. CONCLUSION: Our data suggest that greater pain relief can be expected in patients aged <65 years and that a postoperative lower limb alignment of 1°-4° varus should be pursued. Taking these factors into consideration will help to maximize clinical outcomes, fulfill patient expectations after medial UKA, and subsequently minimize revision rates.