Cartilage regeneration and long term survival in medial OA knee patients treated with HTO and OATS.

Background: Osteoarthritis (OA) of the knee, in most instances primarily, affects medial compartment of knee. Combining Osteochondral Autologous Transfer System (OATS) with Medial Open-Wedge High Tibial Osteotomy (MOWHTO) may represent an integrated approach to sustaining long-term knee functionality in OA patients. Materials and methods: From 2009 to 2016, combined OATS and MOWHTO was performed in 66 knees of 63 patients with medial compartment knee OA. Cartilage regeneration was assessed by 2nd look arthroscopy and Knee function was assessed by knee society scoring (KSS) pre-operatively and post-operatively. The survival rate of MOWHTO plus OATS was assessed. Failure is characterized by the need to convert into total knee replacement. Results: The KSS knee score (from 48.3 to 90.4) and function score (from 42.6 to 88.7) showed a statistically significant improvement (p-value of <0.0001) at a mean follow-up period of 9.49 years. Second look arthroscopy done at the time of implant removal showed 100 % cartilage regeneration with even hyaline cartilage regeneration in 49 out of 57 knees assessed and partial regeneration in 8 knees. The Kaplan Meier survivorship analysis was 96.7 % at the mean 9.49 years after surgery. Only 2 patients needed TKA conversion in follow-up. Conclusion: Combining OATs and valgus MOWHTO provides good option to successfully manage patients of OA and varus malalignment. This resulted in significant improvement in knee function, lowering pain intensity, good cartilage regeneration, and a high survivorship rate for 10 years postoperatively.

Open wedge high tibial osteotomy alters patellofemoral joint kinematics: A multibody simulation study.

Changes in lower limb alignment after open-wedge high tibial osteotomy (owHTO) influence joint kinematics. The aim of this study was to investigate the morphological and kinematic changes of the knee joint, in particular the patellofemoral joint, using a multibody simulation model. OwHTO with an open tibial wedge of 6-12 mm (1 mm intervals) was virtually performed on each of 13 three-dimensional (3D) computer-aided design models (CAD models) derived from computer tomography scans of full-leg cadaver specimens. For each owHTO, an individual biomechanical simulation model was built and knee flexion from 5° to 100° was simulated using a multibody simulation model of the native knee. Morphologic and alignment parameters as well as tibiofemoral and patellofemoral kinematic parameters were evaluated. Almost linear changes in tibial tuberosity trochlea groove (TT-TG) (0.42 mm/1 mm wedge height) were observed which led to pathological values (TT-TG > 20 mm) in 3 out of 13 knees. Furthermore, a 6 mm increase in osteotomy wedge height increased lateral patellofemoral rotation by 0.8° (range: 0.39° to 1.11°) and led to a lateral patellar translation of 0.8 mm (range: 0.37-3.11 mm) on average. Additionally, valgisation led to a medial translation of the tibia and a decrease in the degree of tibial internal rotation during knee flexion of approximately 0.3°/1 mm increase in osteotomy wedge height. The increase in TT-TG and the biomechanical effects observed influence patellofemoral tracking, which may increase retropatellar pressure and are potential risk factors for the development of anterior knee pain.

Postoperative management following osteotomies around the knee: a narrative review.

The present narrative review provides a summary of postoperative therapy modalities and their effectiveness following osteotomies around the knee. The topics that are discussed in the scientific discourse include support of cartilage cell regeneration, pain management, drainage insertion, tourniquet use, pharmacological and mechanical thromboembolism prophylaxis, weight-bearing protocols and bone consolidation. There is evidence for the use of pharmacological thromboembolism prophylaxis and weight-bearing protocols. A standardized postoperative treatment concept following osteotomies around the knee cannot be derived due to lack of evidence for the other topics in current literature.

Should I add orthobiologics to my knee osteotomy practice? A systematic review.

IMPORTANCE: Orthobiologics has seen a renaissance over the last decade as an adjunct therapy during osteotomy due to the limited inherent regenerative potential of damaged intraarticular tissues. AIM OR OBJECTIVE: This systematic review aims to present the latest evidence regarding using orthobiologics with simultaneous high tibial osteotomy (HTO) for knee osteoarthritis. The results of this study may guide surgeons to improve their clinical results and clear the air regarding confusion over whether or not to add orthobiologics to HTO in clinical practice backed by scientific evidence. EVIDENCE REVIEW: According to PRISMA guidelines a systematic search for relevant literature was performed in the PubMed (MEDLINE), Scopus, EMBASE, and Cochrane Library databases of all studies published in English from January 1990 to May 2023. The following search terms were entered into the title, abstract, and keyword fields: "knee" or "osteotomy" AND "valgus" or "varus" AND "regenerative medicine" or "PRP" or "mesenchymal stem cells" or "stem cells" or "BMAC" or "bone marrow" or "growth factors" or "umbilical cord blood-derived mesenchymal stem cell" or "stromal vascular fraction". The AMSTAR-2 checklist was used to confirm the quality of the systematic review. Randomised controlled trials (RCTs), prospective and retrospective comparative cohort studies, case-control studies, and case series were included. Studies that reported clinical outcomes in patients treated with knee osteotomy for varus/valgus knee with concomitant adjunction of regenerative treatment [Platelet-rich plasma (PRP), Adipose-derived stem cells (ADSC), Human Umbilical Cord Blood-Derived (HUCBD), Mesenchymal Stem Cells (MSC), bone marrow aspirate concentrate (BMAC), stromal vascular fraction (SVF)] were included. The outcome measures extracted from the studies were the KOOS score, Lysholm score, Subjective IKDC, WOMAC Score, KSS, Tegner, HSS, radiographic tibiofemoral angle, posterior tibial slope and complications. The current systematic review is registered in the PROSPERO Registry (CRD42023439379). FINDINGS: Osteotomy for unicompartmental arthritis with adjunction of orthobiologics such as PRP, ADSC, HVCBD, MSC, BMAC, and SVF presents a consistent statistically significant clinical improvement compared to preoperative scores regardless of the treatment modality used and there were no notable complications associated with the use of these novel agents. CONCLUSIONS AND RELEVANCE: Orthobiologics and knee osteotomies could improve outcomes in patients with knee osteoarthritis desiring Knee preservation surgeries. However, only a few studies are available on the topic to conclude anything with certainty, the patients included in the studies could not be disintegrated based on the grade of osteoarthritis (OA), type, dosage and frequency of administration of orthobiologic and type of additional surgical procedures used. Therefore, better-structured RCTs are required to implement this finding into routine Orthopaedic practice. LEVEL OF EVIDENCE: Level 4.

Intrafocal injection of tranexamic acid decreases early return to hospital after high tibial osteotomy.

INTRODUCTION: High tibial osteotomy (HTO) is a surgery performed to treat the symptoms and prevent the progression of medial osteoarthritis. Post-operative bleeding has led to early returns to hospital following surgery. Intrafocal injection of tranexamic acid (TXA) could reduce this bleeding complication. The objective of the study was to evaluate the effect of TXA during HTO on the incidence of post-operative complications and early returns to hospital. MATERIALS AND METHODS: This retrospective study included 251 cases of HTO performed between May 2012 and October 2021, with the use of TXA introduced in May 2017. The experimental (n = 102) and control (n = 149) groups were compared as to the rate of post-operative early returns. The influence of confounding factors was evaluated, including age, sex, body mass index (BMI), tobacco use, grade of medial femorotibial osteoarthritis (MFTO), magnitude of angular correction (MAC), and surgery duration. RESULTS: No statistically significant difference was found between the groups with regards to all variables except age. The experimental group was significantly older (54.4 years; σ = 7.5) than the control group (50.4 years; σ = 7.9; p < 0.001). We observed a decrease in emergency department (ED) visits in the experimental group (15.7%) compared to the control (30.2%; p = 0.008) and a decrease in early returns in the experimental group (28.4%) compared to the control (40.5%; p = 0.049). No statistically significant difference in demographic data, MFTO, or MAC was found among patients with and without an early return, in both the experimental and control groups. CONCLUSION: The intrafocal injection of TXA during HTO decreases early returns to hospital.

How effective is proximal fibular osteotomy in redistributing joint pressures? Insights from an HTO comparative in-silico study.

BACKGROUND: Knee osteoarthritis (KOA) represents a widespread degenerative condition among adults that significantly affects quality of life. This study aims to elucidate the biomechanical implications of proximal fibular osteotomy (PFO), a proposed cost-effective and straightforward intervention for KOA, comparing its effects against traditional high tibial osteotomy (HTO) through in-silico analysis. METHODS: Using medical imaging and finite element analysis (FEA), this research quantitatively evaluates the biomechanical outcomes of a simulated PFO procedure in patients with severe medial compartment genu-varum, who have undergone surgical correction with HTO. The study focused on evaluating changes in knee joint contact pressures, stress distribution, and anatomical positioning of the center of pressure (CoP). Three models are generated for each of the five patients investigated in this study, a preoperative original condition model, an in-silico PFO based on the same original condition data, and a reversed-engineered HTO in-silico model. RESULTS: The novel contribution of this investigation is the quantitative analysis of the impact of PFO on the biomechanics of the knee joint. The results provide mechanical evidence that PFO can effectively redistribute and homogenize joint stresses, while also repositioning the CoP towards the center of the knee, similar to what is observed post HTO. The findings propose PFO as a potentially viable and simpler alternative to conventional surgical methods for managing severe KOA, specifically in patients with medial compartment genu-varum. CONCLUSION: This research also marks the first application of FEA that may support one of the underlying biomechanical theories of PFO, providing a foundation for future clinical and in-silico studies.

Influence of variable hinge positioning on coronal and sagittal alignment in uniplanar medial open-wedge high tibial osteotomy.

Purpose: There is a high risk of increasing the posterior tibial slope (PTS) during medially opening-wedge high tibial osteotomy (mowHTO). Most recently, the idea of intentional simultaneous coronal and sagittal correction, using uniplanar cutting techniques has emerged. This study aims to examine the influences of variable hinge positioning and osteotomy gap height on the sagittal and coronal plane. Methods: Twenty uniplanar mowHTOs were performed in standardised (left) solid-foam proximal tibia models. In the different models, hinge position was rotated stepwise by 10°, between 90° (cutting straight medial to lateral) and 0° (cutting straight anterior to posterior) (n = 10). Additionally, gap heights of 5 and 10 mm were produced and analysed. Logistic regression analysis was performed to calculate a predictive regression formula for the relation between gap height, hinge rotation and the changes of medial proximal tibia angle (MPTA), medial and lateral PTS. Results: Between cutting angles of 90 and 20°, the MPTA was mainly influenced by the gap height (0.95° MPTA per 1 mm gap height), but not by the cutting angle. Between 20 and 0°, the MPTA was decreased by 3.6° per 10° of rotation, but not by the gap height. Between cutting angles of 90 and 10°, the PTS was increased linearly by 0.97° per 10° of rotation and by 0.61° per 1 mm gap height. Conclusion: In mowHTO with lateral hinge positions, the MPTA is mainly influenced by gap height. Changes of PTS can be avoided by a straight lateral hinge position. In posterior hinge locations (0-20°), changes of MPTA are mainly caused by hinge rotation, but not by gap height. Level of Evidence: Level III, Case-control study.

Interlaboratory comparison exercises for organically-bound tritium in the development of reference materials of environmental samples.

The complex behavior of tritium and the probability of increasing tritium concentrations released in the environment were the promotors for the research and development of laboratory methods that enable to accurately determine the various forms of tritium including organically-bound tritium (OBT) for public and regulatory assurance. The measurement of tritium is a key step for dose and risk assessment. The Cernavoda Nuclear Power Plant (NPP) in Romania improved preparation methods and tested environmental matrices for OBT analysis through intercomparison exercises. This paper describes the international Organically-Bound Tritium (OBT) intercomparison exercise, organized by the Cernavoda Nuclear Power Plant (NPP) in 2019-2020, using fruit sample (quince) from Cernavoda town. Evaluation of the results from the participating laboratories was performed using both robust analysis (Algorithm A) method described in the ISO 13528:2015 standard and ANOVA method. The results obtained are encouraging as an increased number of participating laboratories did not change the observed dispersion of the results for activity concentration level around 50 Bq/L of combustion water. The stability of the remaining sample will be checked in time to investigate its use as a reference material for OBT analysis at the environmental levels.

Validation of a Three-Dimensional Weight-Bearing Measurement Protocol for Medial Open-Wedge High Tibial Osteotomy.

Three-dimensional (3D) deformity assessment and leg realignment planning is emerging. The aim of this study was to (1) validate a novel 3D planning modality that incorporates the weight-bearing (WB) state (3D WB) by comparing it to existing modalities (3D non-weight-bearing (NWB), 2D WB) and (2) evaluate the influence of the modality (2D vs. 3D) and the WB condition on the measurements. Three different planning and deformity measurement protocols were analyzed in 19 legs that underwent medial open-wedge high tibial osteotomy (HTO): (1) a 3D WB protocol, after 2D/3D registration of 3D CT models onto the long-leg radiograph (LLR) (3D WB), (2) a 3D NWB protocol based on the 3D surface models obtained in the supine position (3D NWB), and (3) a 2D WB protocol based on the LLR (2D WB). The hip-knee-ankle angle (HKA), joint line convergence angle (JLCA), and the achieved surgical correction were measured for each modality and patient. All the measurement protocols demonstrated excellent intermodal agreement for the achieved surgical correction, with an ICC of 0.90 (95% CI: 0.76-0.96)) (p < 0.001). Surgical correction had a higher mean absolute difference compared to the 3D opening angle (OA) when measured with the WB protocols (3D WB: 2.7 ± 1.8°, 3D NWB: 1.9 ± 1.3°, 2D WB: 2.2 ± 1.3°), but it did not show statistical significance. The novel planning modality (3D WB) demonstrated excellent agreement when measuring the surgical correction after HTO compared to existing modalities.

High survivorship rate and good clinical outcomes after high tibial osteotomy in patients with radiological advanced medial knee osteoarthritis: a systematic review.

INTRODUCTION: The role of valgus producing high tibial osteotomy (HTO) for the treatment of advanced knee osteoarthritis (OA) is still controversial. The aim of the current systematic review was to assess survivorship and patient-reported outcomes (PROMs) of high tibial osteotomy in patients with radiological advanced medial knee OA. METHODS: A systematic search of PubMed, Cochrane and EMBASE database was performed in July 2023 in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. Inclusion and exclusion criteria were applied to identify studies investigating the survivorship rate and PROMs of valgus-producing high tibial osteotomy in patients with advanced knee OA at x-ray assessment in the medial compartment at minimum-two-years follow up. Advanced radiological OA was defined as Kellgren Lawrence (K-L) ≥ 3 or Ahlbäch ≥ 2. Survivorship was defined as percentage of patients free of total knee arthroplasty (TKA) at follow-up. Clinical interpretation of provided PROMs were performed according to minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) target values reported in literature. Survivorship data and PROMs scores were extracted, and studies were stratified based on selected study features. The quality of included studies was assessed with modified Coleman score. RESULTS: A total of 18 studies, totalling 1296 knees with a mean age between 46.9 and 67 years old, were included. Average survivorship was of 74.6% (range 60 - 98.1%) at 10-years follow up. The subjective scoring systems showed good results according to MCID and PASS, and postoperative improvements were partially maintained until final follow-up. CONCLUSION: HTO is worth considering as treatment choice even in patients affected by radiological advanced medial knee osteoarthritis. Long term survivorship and good patient reported clinical outcomes could be expected in this population. LEVEL OF EVIDENCE: IV; systematic review of level III-IV studies.

Bilateral Inverted V-shaped High Tibial Osteotomy: A Case Report.

The article describes the case of a young patient with bilateral genu varum deformity, limiting her mobility. The therapeutic decision was a staged reverse V-shaped tibial osteotomy on both knees at a six-month interval. The surgery faced infectious complications on the left side, requiring additional treatment. Despite this, the patient achieved successful correction, with wound healing and bone consolidation. Preoperative planning was crucial, determining specific correction angles for each knee. The reverse V-shaped osteotomy demonstrated satisfactory functional outcomes compared to other techniques. The conclusion emphasizes the effectiveness of reverse V-shaped high tibial osteotomy (HTO) in addressing varus tibial deformities, providing an alternative before considering total knee arthroplasty. Multicenter studies and long-term evaluations are recommended to refine this surgical procedure.

Obesity does not impact complications and conversion to total knee arthroplasty after high tibial osteotomy: A systematic review.

PURPOSE: The purpose of this systematic review is to consolidate outcomes of obese patients undergoing high tibial osteotomy and to investigate the effect of obesity on postoperative outcomes, including symptomatic relief and time to conversion to arthroplasty. METHODS: Medline, Embase and Cochrane Library were searched from database inception up to April 2023 according to PRISMA guidelines by two reviewers. Search terms including 'obesity', 'BMI', 'osteotomy' and 'high tibial osteotomy (HTO)' were included to identify all relevant articles. Only studies that explicitly reported outcomes for obese patients were included. Disagreements in study inclusion or quality assessment were resolved by a senior third reviewer. Metrics compared include time to arthroplasty, preoperative and postoperative mechanical tibiofemoral angle (mTFA), patient-reported satisfaction scores and postoperative complications. RESULTS: Nine studies comparing 973 patients were included. The mean age was 52.7 ± 4.2 years old and 38.4% were male. Six studies performed the medial opening-wedge HTO, and three utilized the medial wedge closing technique. Most studies indicated significant improvement following surgical intervention with satisfactory outcomes in obese and nonobese patients. In addition, differences in complication rates were minimal between obese and nonobese patients (n.s.), while functional scores did not vary significantly. Conversion to total knee arthroplasty was not found to increase in obese patients (n.s.). CONCLUSION: Obesity does not appear to carry a greater complication risk or worse outcomes following high tibial osteotomies, and surgeons should consider HTO a viable option for young obese patients with symptomatic unicompartmental chondral wear with coronal limb malalignment. LEVEL OF EVIDENCE: Level IV.

Higher conversion rate to knee arthroplasty in female patients following medial open-wedge high tibial osteotomy.

PURPOSE: Most studies about medial open-wedge high tibial osteotomy (HTO) reported outcomes without focusing on gender differences. Therefore, the study compared the long-term survival rate and postoperative subjective knee function after HTO in female versus male patients with symptomatic medial compartment knee osteoarthritis. METHODS: The data of three cohorts with long-term outcomes were analysed (n = 245; 32% females; age: 49 ± 7 years; Kellgren Lawrence Grade I 6.1%, II 32.7%, III 42.4%; IV 18.8%). The minimum follow-up was at least 6 years or an earlier conversion to total knee arthroplasty (TKA). The gender-specific survival rate after HTO was calculated after 5 and 10 years and compared using Kaplan-Meier analysis and the logrank test. Baseline characteristics and subjective knee function (International Knee Documentation Committee [IKDC]/Lysholm) were analysed between both genders. RESULTS: Forty of 78 (51.3%) women and 41 of 167 men (24.5%) underwent TKA. HTO survival in females was significantly lower (p = 0.0010). The 5- and 10-year survival rates were 85.9% and 62.6% for females and 93.4% and 77.7% for males. In females and males, from preoperative to the last follow-up, the IKDC (43 ± 15 to 58 ± 17; 47 ± 14 to 67 ± 18) and the Lysholm (42 ± 18 to 72 ± 18; 55 ± 22 to 77 ± 23) improved significantly (all p < 0.0001). Females had significantly lower preoperative and postoperative IKDC (p = 0.0438; p = 0.0035) and Lysholm scores (p = 0.0002; p = 0.0323). But the absolute improvements of the IKDC and Lysholm were not significantly different between genders. CONCLUSIONS: Females had higher conversion rates to TKA and lower knee function at the last follow-up. However, preoperative knee function was lower in females and the absolute improvement following HTO was similar for both genders. In general, females benefit from HTO to treat medial knee arthritis, and TKA could be postponed for half of female patients for more than 10 years. However, surgeons must be aware of the described inferior outcomes in females for realistic patient expectation management. LEVEL OF EVIDENCE: Level II.

Medium to long term of self-report outcomes of high tibial osteotomy in advanced age patients.

PURPOSE: This study aimed to investigate the mid- to long-term benefits of high tibial osteotomy in advanced age patients. METHODS: This retrospective study was conducted in our hospital from January 2017 to January 2021 with data prospectively collected, 47 patients with knee osteoarthritis who over 65 years old were included, and a 1:1 propensity score (PS) of patients < 65 years were matched according to gender, body mass index, and side. Patient demographics, intraooperative and postoperative variables, and patient self-reported outcomes were compared. A generalized linear model was used to screen possible risk factors. RESULTS: A total of 94 consecutive patients were included; the average age of advanced age group was 69.47 + 4.26 years and 57.87 + 5.51 years in the younger group. There were no statistically difference in K-L grade, smoke, drink, comorbidity, ASA, blood loss, operative duration, length of stay, surgical site infection, hinge fracture, DVT, and preooperative and postoperative aFTA; significantly statistical difference of the eFI was found between two groups (P < 0.05). Two groups had comparable VAS and MOMAC scores at one year postoperatively (P > 0.05), while the younger group had lower VAS and WOMAC scores than the advanced age group at the end of follow-up (P < 0.05). Generalized linear model showed both age and eFI were associated with WOMAC scores; there was a statistically significant difference in the effect of eFI on WOMAC scores at different ages (P > 0.05). CONCLUSIONS: Compared with younger patients, advanced age patients have similar short-term benefits, but less long-term benefits. We recommend that patients proposed for HTO be discriminated by eFI, and patients with higher scores should be cautiously selected.

Osseous factors influencing distal tibial rotation in biplane medial opening wedge high tibial osteotomy.

PURPOSE: There is a lack of studies investigating the distal tibial rotation (DTR) during medial opening wedge high tibial osteotomy (MOWHTO). This study was designed to evaluate osseous factors influencing DTR in patients who underwent biplane MOWHTO. METHODS: A total of 106 knee joints in 69 patients who underwent surgery for varus malalignment of knee were reviewed. Based on several software, standard and actual hinge positions were defined in pre-operative and post-operative CT data. Pearson's correlation and Spearman's correlation analysis were performed with DTR change as the dependent variable. Independent variables included angles between standard and actual hinge in the sagittal (ASAHS) and axial (ASAHA) planes, pre-operative and post-operative medial proximal tibial angle, opening width (OW), tuberosity osteotomy angle, flange angle (FA), gap ratio, and hinge fracture. RESULTS: The distal tibia rotated approximately 0.35° internally. Pearson's and Spearman's correlation analysis showed that DTR change was associated with ASAHS, OW, and FA. Larger OW and FA resulted in higher external rotation angles. CONCLUSIONS: DTR change was significantly associated with ASAHS, followed by OW and FA rather than ASAHA if only considering osseous factors in biplane MOWHTO. The distal tibia tended to rotate externally when the actual hinge was inclined posteriorly to the standard hinge in the sagittal planes, but rotate externally or internally when the actual hinge was inclined anteriorly.

Clinical Outcomes Following Use of Tranexamic Acid in High Tibial Osteotomy: A Systematic Review.

This study aimed to evaluate the clinical outcomes following administration of tranexamic acid (TXA) in patients undergoing high tibial osteotomy (HTO) through a systematic review of current available evidence. A systematic database search of PubMed, Embase and Cumulative Index of Nursing and Allied Health Literature (CINAHL) was performed from inception up to December 2022, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). Inclusion criteria were (i) randomised control trials, cohort studies or case-control studies that had more than 10 patients; (ii) studies reporting outcomes after TXA administration, of any route, before or after HTO, compared to placebo, control and different doses or routes; and (iii) studies reporting blood loss, including haemoglobin (Hb) drop, estimated blood loss, transfusion requirement and complications. Case reports, reviews, abstracts, non-HTO studies, non-human studies and duplicates were excluded. A synthesized comparison of drain output, wound complications, transfusion requirement and pooled analyses of blood loss and Hb drop was performed. Eleven studies involving 974 patients were included. Nine studies had placebo comparison, and two used single-dose TXA versus multiple doses. All studies reported on postoperative hemoglobin and nine on blood loss. In the six TXA versus placebo studies reporting on total blood loss, the TXA group had a pooled, estimated standardised mean difference (SMD) in blood loss of -2.37 (95% confidence interval (CI) -3.67, -1.07; P = 0.0004). For the Hb drop, on postoperative days (PODs) one, two, and five, the SMDs were -0.97 (95% CI -1.19, -0.75; P < 0.00001) for POD1, -0.74 (95% CI -1.03, -0.46; P < 0.00001) for POD2 and -0.87 (95% CI -1.10, -0.64; P < 0.00001) for POD5. TXA administration in HTO significantly reduces perioperative blood loss. This can greatly improve recovery, reduce complications and shorten length of stay. This is especially pertinent given supply shortages of NHS blood resources.

A simple formula to control posterior tibial slope during proximal tibial osteotomies.

BACKGROUND: High tibial osteotomy surgery is a widely successful joint-preserving procedure which alters the hip-knee-ankle axis which can delay the progression of osteoarthritis; however, conventional osteotomy surgical procedures do not adequately control the posterior tibial slope. This study aimed to determine the key variables influencing posterior tibial slope during high tibial osteotomy and provide a simple means of implementing the findings during pre-operative planning. METHODS: A virtual cohort of twenty-eight proximal tibia geometries of knee osteoarthritis patients was used in the study. Firstly, absolute posterior tibial slope values were contrasted using anatomical and posterior mechanical axis measurement approaches. Secondly, the influence of variables affecting posterior tibial slope change during osteotomy surgery was investigated using 3D preoperative planning surgical simulation and analytical modelling. FINDINGS: There was a poor correlation (R2 = 0.38) between the different clinical measurements of posterior tibial slope; with an average of 7.0 ± 1.3° and 14.8 ± 2.2° respectively. An analytical solution for the change in posterior tibial slope was derived based on the hinge axis angle and the osteotomy opening angle. For three different opening angles (6°, 9° and 12°) and seven different hinge axis orientations (-30° to +30°), the results obtained were identical for the analytical model and the 3D preoperative planning. INTERPRETATION: This study determined that the key variables affecting posterior tibial slope during high tibial osteotomy are the osteotomy opening angle and the hinge axis orientation. The derived formula provides a simple means of determining the change in posterior tibial slope resulting from a particular surgical approach.

Artificial intelligence-based analyses of varus leg alignment and after high tibial osteotomy show high accuracy and reproducibility.

PURPOSE: The aim of this study was to investigate the performance of an artificial intelligence (AI)-based software for fully automated analysis of leg alignment pre- and postoperatively after high tibial osteotomy (HTO) on long-leg radiographs (LLRs). METHODS: Long-leg radiographs of 95 patients with varus malalignment that underwent medial open-wedge HTO were analyzed pre- and postoperatively. Three investigators and an AI software using deep learning algorithms (LAMA™, ImageBiopsy Lab, Vienna, Austria) evaluated the hip-knee-ankle angle (HKA), mechanical axis deviation (MAD), joint line convergence angle (JLCA), medial proximal tibial angle (MPTA), and mechanical lateral distal femoral angle (mLDFA). All measurements were performed twice and the performance of the AI software was compared with individual human readers using a Bayesian mixed model. In addition, the inter-observer intraclass correlation coefficient (ICC) for inter-observer reliability was evaluated by comparing measurements from manual readers. The intra-reader variability for manual measurements and the AI-based software was evaluated using the intra-observer ICC. RESULTS: Initial varus malalignment was corrected to slight valgus alignment after HTO. Measured by the AI algorithm and manually HKA (5.36° ± 3.03° and 5.47° ± 2.90° to - 0.70 ± 2.34 and - 0.54 ± 2.31), MAD (19.38 mm ± 11.39 mm and 20.17 mm ± 10.99 mm to - 2.68 ± 8.75 and - 2.10 ± 8.61) and MPTA (86.29° ± 2.42° and 86.08° ± 2.34° to 91.6 ± 3.0 and 91.81 ± 2.54) changed significantly from pre- to postoperative, while JLCA and mLDFA were not altered. The fully automated AI-based analyses showed no significant differences for all measurements compared with manual reads neither in native preoperative radiographs nor postoperatively after HTO. Mean absolute differences between the AI-based software and mean manual observer measurements were 0.5° or less for all measurements. Inter-observer ICCs for manual measurements were good to excellent for all measurements, except for JLCA, which showed moderate inter-observer ICCs. Intra-observer ICCs for manual measurements were excellent for all measurements, except for JLCA and for MPTA postoperatively. For the AI-aided analyses, repeated measurements showed entirely consistent results for all measurements with an intra-observer ICC of 1.0. CONCLUSIONS: The AI-based software can provide fully automated analyses of native long-leg radiographs in patients with varus malalignment and after HTO with great accuracy and reproducibility and could support clinical workflows. LEVEL OF EVIDENCE: Diagnostic study, Level III.

High tibial lateral closing wedge and opening wedge valgus osteotomy produce different effects on posterior tibial slope and patellar height.

Objective: To compare the clinical outcomes of performing a closed tibial high osteotomy with an open osteotomy and the changes in posterior tibia slope and patellar height. Methods: Methods were collected from three hundred and forty patients (440 knees) with high tibial osteotomy performed from January 2019 to January 2020. Forty patients (50 knees) had a lateral closed wedge tibial osteotomy (LCWHTO), and 300 patients (390 knees) had a medial open wedge tibial osteotomy (MOWHTO). The follow-up periods were 20.5 months and 19.9 months, respectively. At the final follow-up visit, both groups evaluated the Lysholm score and joint range of motion (ROM). Changes in preoperative and postoperative mechanical axis deviation (MAD), proximal medial tibial angle (MPTA), posterior tibial slope (PTS), and M-K index were compared between the two groups of patients. Results: Lysholm scores were 79.6 ± 15.6 preoperatively and 96.0 ± 5.0 postoperatively in the LCWHTO group (p < 0.01); 83.7 ± 16.0 preoperatively and 94.3 ± 9.1 postoperatively in the MOWHTO group (p < 0.01). ROM was 136.0° ± 8.4° preoperatively and 133.2° ± 10.1° postoperatively in the LCWHTO group (p > 0.05); 136.5° ± 8.4° preoperatively and 135.7° ± 9.3° postoperatively in the MOWHTO group (p > 0.05). the MAD was (26.5 ± 4.1) mm preoperatively and 0.3 ± 2.9 mm postoperatively in the LCWHTO group (p < 0.01); 21.8 ± 6.5 mm preoperatively and -0.3 ± 2.6 mm postoperatively in the MOWHTO group (p < 0.01). The MPTA in the LCWHTO group was 75.3° ± 3.2° preoperatively and 89.5° ± 2.4° postoperatively (p < 0.01). 77.1° ± 3.0° preoperatively and 90.6° ± 2.7° postoperatively in the MOWHTO group (p < 0.01). M-K index was 0.78 ± 0.08 preoperatively and 0.79 ± 0.07 postoperatively in the LCWHTO group (p > 0.05). 0.78 ± 0.05 before and 0.75 ± 0.05 after surgery in the MOWHTO. 10.8° ± 3.0° PTS before and 8.1° ± 3.4° after surgery in the LCWHTO group (p < 0.05); 10.2° ± 3.1° preoperatively and 10.9° ± 4.0° postoperatively (p > 0.05). Conclusions: LCWHTO decreases the PTS and has no effect on patellar height; MOWHTO does not affect the PTS but decreases patellar height. The patient should individualize the choice of the osteotomy.

Angle Stable Plate Fixation vs Hemicallotasis in Medial Opening Wedge High Tibial Osteotomy: A Comparative Study.

Background: Varus alignment associated with medial compartment degeneration is the most common presentation of knee osteoarthritis and often presents in young active adults where arthroplasty might be unsuitable. Purpose: To compare the accuracy of the angle stable medial high tibia plate and self-adjusting HTO (high tibial osteotomy) fixator in achieving correction of varus deformity of the knee by medial opening wedge HTO and to evaluate functionality between the groups. Study Design: Prospective randomized control study. Methods: Forty patients each underwent medial opening wedge high tibial osteotomy with acute correction and stabilization using the angle stable plate (ASP group) or with the hemicallotasis technique using the self-adjusting HTO external fixator (HCO group). Anatomical and functional outcomes were compared to the pre-operative values at the 6th and 12th month. Results: The FTA (femoro-tibial axis), mechanical axis, and functional scores improved significantly in both groups. There was also a significant change in the patellar height and tibial slope. Except for a better KOOS (Knee Injury and Osteoarthritis Outcome Score) in the angle stable plate group at the 6-month follow-up, there were no significant differences between the groups. Conclusion: Both methods of performing a medially based proximal tibial osteotomy gave equivalent outcomes at the 1-year follow-up.