Machine Learning Did Not Outperform Conventional Competing Risk Modeling to Predict Revision Arthroplasty.

BACKGROUND: Estimating the risk of revision after arthroplasty could inform patient and surgeon decision-making. However, there is a lack of well-performing prediction models assisting in this task, which may be due to current conventional modeling approaches such as traditional survivorship estimators (such as Kaplan-Meier) or competing risk estimators. Recent advances in machine learning survival analysis might improve decision support tools in this setting. Therefore, this study aimed to assess the performance of machine learning compared with that of conventional modeling to predict revision after arthroplasty. QUESTION/PURPOSE: Does machine learning perform better than traditional regression models for estimating the risk of revision for patients undergoing hip or knee arthroplasty? METHODS: Eleven datasets from published studies from the Dutch Arthroplasty Register reporting on factors associated with revision or survival after partial or total knee and hip arthroplasty between 2018 and 2022 were included in our study. The 11 datasets were observational registry studies, with a sample size ranging from 3038 to 218,214 procedures. We developed a set of time-to-event models for each dataset, leading to 11 comparisons. A set of predictors (factors associated with revision surgery) was identified based on the variables that were selected in the included studies. We assessed the predictive performance of two state-of-the-art statistical time-to-event models for 1-, 2-, and 3-year follow-up: a Fine and Gray model (which models the cumulative incidence of revision) and a cause-specific Cox model (which models the hazard of revision). These were compared with a machine-learning approach (a random survival forest model, which is a decision tree-based machine-learning algorithm for time-to-event analysis). Performance was assessed according to discriminative ability (time-dependent area under the receiver operating curve), calibration (slope and intercept), and overall prediction error (scaled Brier score). Discrimination, known as the area under the receiver operating characteristic curve, measures the model's ability to distinguish patients who achieved the outcomes from those who did not and ranges from 0.5 to 1.0, with 1.0 indicating the highest discrimination score and 0.50 the lowest. Calibration plots the predicted versus the observed probabilities; a perfect plot has an intercept of 0 and a slope of 1. The Brier score calculates a composite of discrimination and calibration, with 0 indicating perfect prediction and 1 the poorest. A scaled version of the Brier score, 1 - (model Brier score/null model Brier score), can be interpreted as the amount of overall prediction error. RESULTS: Using machine learning survivorship analysis, we found no differences between the competing risks estimator and traditional regression models for patients undergoing arthroplasty in terms of discriminative ability (patients who received a revision compared with those who did not). We found no consistent differences between the validated performance (time-dependent area under the receiver operating characteristic curve) of different modeling approaches because these values ranged between -0.04 and 0.03 across the 11 datasets (the time-dependent area under the receiver operating characteristic curve of the models across 11 datasets ranged between 0.52 to 0.68). In addition, the calibration metrics and scaled Brier scores produced comparable estimates, showing no advantage of machine learning over traditional regression models. CONCLUSION: Machine learning did not outperform traditional regression models. CLINICAL RELEVANCE: Neither machine learning modeling nor traditional regression methods were sufficiently accurate in order to offer prognostic information when predicting revision arthroplasty. The benefit of these modeling approaches may be limited in this context.

Bone Marrow Stimulation for Osteochondral Lesions of the Tibial Plafond Yields Good Patient-Reported Outcomes in Daily Living but Moderate Outcomes in Sports Activities at 2- to 22-Years Follow-Up.

PURPOSE: To assess the patient-reported outcomes, as well as the revision and complication rates, of patients who underwent arthroscopic bone marrow stimulation (BMS) for an osteochondral lesion of the tibial plafond (OLTP). METHODS: Patients with an OLTP treated with arthroscopic BMS at a minimum follow-up of 2-years were cross-sectionally included from a historical database. The primary outcome was the Numeric Rating Scale (NRS) during walking. Secondary outcomes included the NRS in rest and during running, and the Foot and Ankle Outcome Score. Additionally, the association of baseline patient and lesion demographics with follow-up patient-reported outcome measures (PROMs) was assessed with the Spearman rank correlation test. A subanalysis was performed for PROMs in patients with or without a coexisting talar (i.e., bipolar) lesion. Finally, the revision surgery (i.e., repeat surgery for the OLTP) and complication rates were assessed. RESULTS: Fifty-one patients were included at a mean 8.8 (standard deviation [SD] = 5.7, range, 2-22) years follow-up. Seventy-three percent of patients had a solitary OLTP, and 27% had a coexisting talar (bipolar) lesion. Males had a significantly higher rate of bipolar lesions compared to females (P ≤ .01), and patients with a bipolar lesion had a significantly larger OLTP lesion diameter (P = .02) and volume (P = .04). At final follow-up, the mean NRS during walking was 1.9 (SD = 2.3) out of 10. Anterior-posterior OLTP size (r = 0.36; P ≤ .01) was significantly associated with a higher NRS pain score during walking, although the presence of bipolar lesions did not result in inferior clinical outcomes. At final follow-up, 6% of patients underwent revision surgery. Minor complications were observed in 12% of patients. CONCLUSIONS: Arthroscopic BMS for OLTP results in favorable patient-reported outcomes at mid- to long-term follow-up, although moderate outcomes were observed in sports activities. Lesion size was associated with increased pain scores, although bipolar lesions did not result in inferior patient-reported outcomes. Six percent of patients required revision surgery, and 12% of patients had minor complications after surgery. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

The deltoid ligament is constantly formed by four fascicles reaching the navicular, spring ligament complex, calcaneus and talus.

PURPOSE: The medial collateral ligament of the ankle, or deltoid ligament, can be injured in up to 40% of patients who sustain an ankle inversion sprain. Reporting injuries of the deltoid ligament is not easy due to confusion in the current anatomical descriptions, with up to 16 fascicles described, with variable frequencies. The purpose of this study was to clarify the anatomy of the deltoid ligament. METHODS: Thirty-two fresh-frozen ankle specimens were used for this study. Careful dissection was undergone until full visualization of the deltoid ligament was achieved and measurements taken. RESULTS: The deltoid ligament was found to have four constant fascicles in two layers. The superficial layer consists of the tibionavicular, tibiospring and tibiocalcaneal fascicles, while the deep layer consists of the tibiotalar fascicle. Measurements of these fascicles are given in detail. The tibiotalar fascicle and the anterior part of the tibionavicular fascicle were found to be intra-articular structures. CONCLUSION: The deltoid ligament has a constant number of fascicles divided into a superficial and a deep layer. This clarification of the anatomy and terminology of the deltoid ligament and its fascicles will help clinical view, diagnosis and (interdoctor)communication and treatment. The ligamentous fibres of the deep layer, as well as the anterior fibres of the superficial layer (tibionavicular fascicle) are intra-articular, which could negatively impact its healing capacity, explaining chronicity of these types of injuries. LEVEL OF EVIDENCE: Not applicable (cadaveric study).

Most elite athletes return to preinjury competitive activity after surgical treatment for medial malleolus stress fractures.

PURPOSE: To provide return-to-performance outcomes after surgical treatment for medial malleolus stress fractures in the elite athlete. Additionally, to describe an individualised surgical approach in the management of medial malleolus stress fractures. METHODS: Five athletes (six ankles) underwent surgical treatment for a medial malleolus stress fracture. The surgical technique was based on the extent of the fracture line in steps with first arthroscopic debridement of bony spurs, microfracturing of the fracture line and screw fixation. Return-to-performance data included time to return to sport-specific training, normal training, first competitive activity, performance and the return-to-performance rate. RESULTS: Patients returned to sport-specific training at a median of 10 weeks. They started normal training at 16 weeks postoperatively and returned to their first competitive activity after 19 weeks. All patients had bony spurs on the distal tibia which were arthroscopically debrided. One patient received arthroscopic debridement of bony spurs alone. Four patients received additional microfracturing of the fracture line and three patients received screw fixation. All patients achieved clinical and radiographic union on follow-up computed tomography scan at 3 months postsurgery. At latest follow-up, no refractures nor hardware complications, nor any other complications were observed. CONCLUSION: Arthroscopic debridement of bony spurs, debridement and microfracturing of the fracture line and screw fixation are all viable surgical tools in the management of medial malleolus stress fractures in elite athletes. The surgical approach containing these options should be tailored to the individual athlete based on the fracture line in the sagittal plane. While most athletes return to full competitive activity in 3-4 months, time to self-reported return to full performance is often much longer. LEVEL OF EVIDENCE: Level IV.

Enhancing precision in osteochondral lesions of the talus measurements and improving agreement in surgical decision-making using weight-bearing computed tomography and distance mapping.

PURPOSE: Weight-bearing computed tomography (WBCT) enables the creation of a three-dimensional (3D) model that represents the ankle morphology in a standing position. Distance mapping (DM) is a complementary feature that uses color coding to represent the relative intraarticular distance and can be used to outline intraarticular defects. Consequently, DM offers a novel approach to delineating osteochondral lesions of the talus (OLT), allowing for the quantification of its surface, volume and depth. The reliability of DM for OLT measurements has yet to be thoroughly evaluated. This study primarily aims to determine the reliability of DM in measuring the surface, depth and volume of OLT. A secondary objective is to ascertain whether measurements obtained through DM, when integrated with a predefined treatment algorithm, can facilitate consensus among surgeons regarding the optimal surgical intervention. METHODS: This cohort comprised 36 patients with 40 OLTs evaluated using WBCT and DM. Two raters used DM to determine the lesion boundary (LB) and lesion fundus (LF) and calculate the lesion depth, surface and volume. The raters were asked to choose between bone marrow stimulation, autologous matrix-induced chondrogenesis and osteochondral transposition based on the measurement. Inter-rater and intra-rater agreement was measured. RESULTS: Interclass correlation of the lesion's depth surface produced an excellent inter-rater and intra-rater agreement of 0.90-0.94 p < 0.001. Cohen's κ agreement analysis of the preferable preoperative plan produced a κ = 0.834, p < 0.001, indicating a near-perfect agreement. CONCLUSION: WBCT-based 3D modules and DM can be used to measure the lesion's surface, depth and volume with excellent inter-rater and inter-rater agreement; using this measurement and a predetermined treatment algorithm, a near-perfect inter-rater agreement for the preoperative planning was reached. WBCT in conjunction with AI capabilities could help determine the type of surgery needed preoperatively, evaluate the hindfoot alignment and assess if additional surgeries are needed. LEVEL OF EVIDENCE: Level III.

No difference between 5 and 6 weeks of non-weight bearing after osteochondral grafts for medial osteochondral defects of the talus with medial malleolar osteotomy.

PURPOSE: The present study aimed to compare the clinical outcomes and safety at a 1-year follow-up after 5 or 6 weeks of non-weight bearing after a Talar OsteoPeriostic grafting from the Iliac Crest (TOPIC) for a medial osteochondral lesion of the talus (OLT). METHODS: A retrospective comparative case-control analysis of prospectively followed patients who underwent a TOPIC procedure with medial malleolus osteotomy was performed. Patients were matched in two groups with either 5 or 6 weeks of non-weight bearing. Clinical outcomes were evaluated using the Numeric Rating Scale (NRS) during walking, rest, running, and stairclimbing. Additionally, the Foot and Ankle Outcome Score (FAOS) and American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score were assessed. Moreover, radiology and complications were assessed. RESULTS: Eleven patients were included in the 5-week non-weight bearing group and 22 in the 6-week non-weight bearing group. No significant differences were found in any of the baseline variables. The NRS during walking in the 5-week group improved by 3.5 points and 4 points for the 6-week group (p = 0.58 at 1-year post-operatively). In addition, all other NRS scores, FAOS subscales and the AOFAS scores improved (all n.s. at 1 year follow-up). No significant differences in radiological (osteotomy union and cyst presence in the graft) were found. Moreover, no significant differences were found in terms of complications and reoperations. CONCLUSION: No statistical significant differences were found in terms of clinical, radiological and safety outcomes between 5 or 6 weeks of non-weight bearing following a TOPIC for a medial OLT. LEVEL OF EVIDENCE: Level III, Therapeutic.

The minimal important change is not a universal fixed value across diagnoses when using the FAOS and FAAM in patients undergoing elective foot and ankle surgery.

PURPOSE: This study aimed to calculate region and diagnosis-specific minimal important changes (MICs) of the Foot and Ankle Outcome Score (FAOS) and the Foot and Ankle Ability Measure (FAAM) in patients requiring foot and ankle surgery and to assess their variability across different foot and ankle diagnoses. METHODS: The study used routinely collected data from patients undergoing elective foot and ankle surgery. Patients had been invited to complete the FAOS and FAAM preoperatively and at 3-6 months after surgery, along with two anchor questions encompassing change in pain and daily function. Patients were categorised according to region of pathology and subsequent diagnoses. MICs were calculated using predictive modelling (MICPRED) and receiver operating characteristic curve (MICROC) method and evaluated according to strict credibility criteria. RESULTS: Substantial variability of the MICs between forefoot and ankle/hindfoot region was observed, as well as among specific foot and ankle diagnoses, with MICPRED and MICROC values ranging from 7.8 to 25.5 points and 9.4 to 27.8, respectively. Despite differences between MICROC and MICPRED estimates, both calculation methods exhibited largely consistent patterns of variation across subgroups, with forefoot conditions systematically showing smaller MICs than ankle/hindfoot conditions. Most MICs demonstrated high credibility; however, the majority of the MICs for the FAOS symptoms subscale and forefoot conditions exhibited insufficient or low credibility. CONCLUSION: The MICs of the FAOS and FAAM vary across foot and ankle diagnoses in patients undergoing elective foot and ankle surgery and should not be used as a universal fixed value, but recognised as contextual parameters. This can help clinicians and researchers in more accurate interpretation of the FAOS and FAAM change scores. LEVEL OF EVIDENCE: Level IV.

Large variation in postoperative rehabilitation protocols following operative treatment of osteochondral lesions of the talus: A systematic review and meta-analysis on >200 studies.

PURPOSE: A treatment-specific rehabilitation protocol and well-defined return-to-play criteria guide clinical decision-making on return to normal function, activity, sports and performance after surgical treatment for osteochondral lesion of the talus (OLT). The optimal rehabilitation protocols in the current literature remain unclear. The purpose of this study was to explore the existing literature on rehabilitation protocols from the early postoperative phase to return to sport onwards after different types of surgical treatment of OLTs. METHODS: PubMed, Embase, CDSR, DARE and Central were searched systematically from inception to February 2023 according to the PRISMA 2020 guidelines. All clinical studies with a description of postoperative rehabilitation criteria after surgical treatment of OLTs were included. The primary outcome of this study is the extent of reportage for each rehabilitation parameter expressed in percentage. The secondary outcome is the reported median time for each parameter in rehabilitation protocols for all different treatment modalities (type of surgery). The median time, expressed as number of weeks, for each parameter was compared between different types of surgery. RESULTS: A total of 227 articles were included reporting on 255 different rehabilitation protocols from seven different types of surgery. Weight-bearing instructions were reported in 84%-100% and the use of a cast or walker was prescribed in 27%-100%. Range of motion exercises were described in 54%-100% whereas physical therapy was advised in 21%-67% of the protocols. Any advice on return to sport was described in 0%-67% protocols. A nonparametric analysis of variance showed significant differences between the different surgical treatment modalities for the following parameters between the treatment groups: time to full weight-bearing (p < 0.0003) and return to high impact level of sports (p < 0.0003). Subjective or objective criteria for progression during rehabilitation were reported in only 24% of the studies. CONCLUSION: An in-depth exploration of the current literature showed substantial variation in postoperative rehabilitation guidelines with an associated underreporting of the most important rehabilitation parameters in postoperative protocols after surgical treatment of OLTs. Furthermore, nearly all rehabilitation protocols were constructed according to a time-based approach. Only one out of four reported either objective or subjective criteria. LEVEL OF EVIDENCE: Level IV, systematic review.

Consensus on the definition and criteria for failure of surgical treatment in bacterial arthritis of a native joint: An international Delphi study.

PURPOSE: The literature presents a wide range of success rates for a single surgical intervention of bacterial-septic-arthritis, and there is a lack of clear criteria for identifying treatment failure and making decisions about reintervention. This Delphi study aims to establish a consensus among an international panel of experts regarding the definition of treatment failure and the criteria for reintervention in case of bacterial arthritis. METHODS: The conducting and reporting Delphi studies (CREDES) criteria were used. Data from a systematic review was provided as the basis for the study. A list of 100 potential experts were identified. The study was designed and conducted as follows: (I) identification and invitation of an expert panel, (II) informing the participating expert panel on the research question and subject, and (III) conducting two or three Delphi rounds to reach consensus on explicit research items. Potential criteria were rated on a five-point Likert scale. RESULTS: Sixty orthopaedic experts from nine countries participated in this Delphi study, with 55 completing all three rounds. The mean experience as an orthopaedic surgeon was 15 years (SD ± 9). Strong (96%) consensus was reached on the definition of treatment failure: the persistence of physical signs of arthritis (e.g., pain and swelling) and/or systemic inflammation (e.g., fever and no improvement in CRP) despite surgical and antibiotic treatment. Furthermore, consensus (>80%) was reached on six criteria influencing the decision for reintervention; pain (81%), sepsis (98%), fever (88%), serum CRP (93%), blood culture (82%), and synovial fluid culture (84%). CONCLUSION: The definition of treatment failure for bacterial arthritis after a single surgical intervention was established through a three-round Delphi study. Additionally, consensus was reached on six criteria that are helpful for determining the need for reintervention. This definition and these criteria may help in the development of clinical guidelines, and will empower physicians to make more precise and consistent decisions regarding reintervention for patients, ultimately aiming to reduce over- and undertreatment and improve patient outcomes. LEVEL OF EVIDENCE: Level V.

The mind matters: Psychological factors influence subjective outcomes following unicompartmental knee arthroplasty-A prospective study.

PURPOSE: This study aimed to investigate how psychological factors, including pain catastrophizing (PC), anxiety and depression affect preoperative and postoperative subjective outcomes in patients undergoing unicompartmental knee arthroplasty (UKA). METHODS: A prospective comparative study was performed among 150 patients undergoing medial or lateral UKA for isolated unicompartmental osteoarthritis. Patients were categorized based on their preoperative PC and Hospital Anxiety and Depression Scale, stratifying them into groups with PC, anxiety or depression, and those without these psychological factors. Patient-reported outcomes, including the Knee Injury and Osteoarthritis Outcome Score-Physical function Short form (KOOS-PS), 5-level EQ5D Visual Analogue Scale (EQ5D-VAS), Forgotten Joint Score (FJS) and Numeric Rating Scale for pain (NRS-pain) were compared between groups preoperatively and at 6-, 12-, and 24-month follow-up. RESULTS: At 24 months, PC patients had inferior outcomes in KOOS-PS (66.9 ± 16.5 vs. 77.6 ± 14.7, p = .008), EQ5D-VAS (63.5 ± 19.9 vs. 78.9 ± 20.1, p = .003) and FJS (73.7 ± 14.3 vs. 84.6 ± 13.8, p = .003). Anxiety was associated with inferior KOOS-PS (65.4 ± 15.2 vs. 78.2 ± 14.5, p = <.001), EQ5D-VAS (64.2 ± 23.2 vs. 79.3 ± 19.4, p = .002), FJS (75.7 ± 16.8 vs. 84.6 ± 13.4, p = .008) and NRS-pain (27.4 ± 24.6 vs. 13.7 ± 19.3, p = .023) at 24 months. Depression consistently resulted in inferior outcomes in KOOS-PS, EQ5D-VAS, FJS and NRS-pain across all follow-up assessments (p = <.05). Additionally, patients with anxiety and depression experienced longer length of hospital stay compared to those without these psychological factors (anxiety: 2.3 ± 2.3 vs. 0.8 ± 0.8 days, p = .006; depression: 2.3 ± 2.4 vs. 0.8 ± 0.8 days, p = .017). CONCLUSIONS: Preoperative PC, anxiety and depression are associated with inferior subjective outcomes both prior to and following UKA. Among these factors, depression seemed to exert the most substantial adverse impact on outcomes following UKA. Patients with anxiety and depression had an extended duration of hospitalization lasting over twice as long as patients without these psychological factors. It seems that inferior outcomes primarily stem from the suboptimal preoperative condition rather than an inherent inability to benefit from UKA. LEVEL OF EVIDENCE: Level II, prospective study.

Sex-specific analysis in patients undergoing Talar OsteoPeriostic grafting from the Iliac Crest (TOPIC) for large osteochondral lesions of the talus.

PURPOSE: The purpose of the present study is to assess the gender-specific differences in the presentation and outcomes following Talar OsteoPeriostic grafting from the Iliac Crest (TOPIC) between male and female patients. METHODS: A prospective comparative analysis was performed comparing consecutive female and male patients having been treated by the press-fit TOPIC procedure. Clinical comparative assessment preoperatively and at 12 months of follow-up included determination of the Numeric Rating Scale (NRS) scores for pain during walking (primary outcome), at rest and during stair-climbing. The Foot and Ankle Outcome Score (FAOS) was also assessed. A computed tomography (CT) scan was performed for lesion size, morphology and localization determination preoperatively as well as 10-12 weeks postoperatively to assess the union of the osteotomy site and at 1 year postoperatively to assess consolidation of the graft as well as intra-graft cyst development. RESULTS: A total of 48 patients (30 women, 18 men) were eligible for inclusion. Both men and women demonstrated significant functional improvements postoperatively concerning the clinical outcomes with no significant differences between men and women (n.s.) except for a significantly greater improvement in postoperative FAOS pain scores in women. Men presented with OLTs significantly larger in both surface area (208 mm2 for males versus 155 mm2 for females, p < 0.05) as well as lesion volume (3.0 cm3 for males versus 1.8 cm3 for females, p < 0.05). At 1-year postoperatively, all patients showed graft consolidation. Cyst formation was present in 11 females (37% of the group) and 10 males (59% of the group), respectively (n.s.). CONCLUSION: Both males and females showed clinically relevant improvements in the clinical outcomes after undergoing the TOPIC procedure with significant differences in preoperative lesion size. The TOPIC procedure is a good treatment strategy for large OLTs in both men and women. LEVEL OF EVIDENCE: Level III, comparative prospective clinical cohort.

From technical to understandable: Artificial Intelligence Large Language Models improve the readability of knee radiology reports.

PURPOSE: The purpose of this study was to evaluate the effectiveness of an Artificial Intelligence-Large Language Model (AI-LLM) at improving the readability of knee radiology reports. METHODS: Reports of 100 knee X-rays, 100 knee computed tomography (CT) scans and 100 knee magnetic resonance imaging (MRI) scans were retrieved. The following prompt command was inserted into the AI-LLM: 'Explain this radiology report to a patient in layman's terms in the second person:[Report Text]'. The Flesch-Kincaid reading level (FKRL) score, Flesch reading ease (FRE) score and report length were calculated for the original radiology report and the AI-LLM generated report. Any 'hallucination' or inaccurate text produced by the AI-LLM-generated report was documented. RESULTS: Statistically significant improvements in mean FKRL scores in the AI-LLM generated X-ray report (12.7 ± 1.0-7.2 ± 0.6), CT report (13.4 ± 1.0-7.5 ± 0.5) and MRI report (13.5 ± 0.9-7.5 ± 0.6) were observed. Statistically significant improvements in mean FRE scores in the AI-LLM generated X-ray report (39.5 ± 7.5-76.8 ± 5.1), CT report (27.3 ± 5.9-73.1 ± 5.6) and MRI report (26.8 ± 6.4-73.4 ± 5.0) were observed. Superior FKRL scores and FRE scores were observed in the AI-LLM-generated X-ray report compared to the AI-LLM-generated CT report and MRI report, p < 0.001. The hallucination rates in the AI-LLM generated X-ray report, CT report and MRI report were 2%, 5% and 5%, respectively. CONCLUSIONS: This study highlights the promising use of AI-LLMs as an innovative, patient-centred strategy to improve the readability of knee radiology reports. The clinical relevance of this study is that an AI-LLM-generated knee radiology report may enhance patients' understanding of their imaging reports, potentially reducing the responder burden placed on the ordering physicians. However, due to the 'hallucinations' produced by the AI-LLM-generated report, the ordering physician must always engage in a collaborative discussion with the patient regarding both reports and the corresponding images. LEVEL OF EVIDENCE: Level IV.

Low annual revision rate in ankle distraction for ankle osteoarthritis: A systematic review and meta-analysis.

PURPOSE: Ankle osteoarthritis severely impacts patients' mental and physical quality of life. Besides total ankle replacement and ankle arthrodesis, ankle distraction has been shown to be a promising alternative. The primary aim of the present study was to determine the annual revision rates (ARRs) after ankle distraction. The secondary aim was to obtain an overview of patient-reported outcome measures and functional outcomes. METHODS: A literature search until November 2023 was performed. Methodological quality was assessed using the methodological index for non-randomised studies criteria. Primary outcome was the ARR which was log-transformed and pooled using a random effects model. Secondary outcomes were pooled using a simplified pooling technique and included the American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Scale (AOFAS), range of motion (ROM) and post-operative complications. RESULTS: The literature search resulted in 287 articles, of which 10 studies, comprising 602 patients, were included. The patients had a pooled mean age of 47 years (range of means: 40-68) and a mean follow-up of 35 months (range of means: 24-48). The overall methodological quality was moderate to fair. The pooled ARR after ankle distraction was 4% (95% confidence interval [CI], 3%-7%). Pooling of AOFAS showed mean 26-point improvement (from 54 to 80). Additionally, ROM dorsiflexion improved at 5°, and the plantarflexion remained at 31°. The overall complication rate was 41% (95% CI, 35%-48%), of which 77% (95% CI, 67%-85%) were pin-tract infections. CONCLUSION: Ankle distraction results in an ARR of 4% (95% CI, 3%-7%) with clinically relevant improved AOFAS scores. The overall complication rate is 41% and is mainly attributable to treatable pin-tract infections (77% of recorded complications). LEVEL OF EVIDENCE: Level IV, Systematic Review and Meta-Analysis.

The phenotypic diversity of anteromedial osteoarthritis before and after treatment with medial unicompartmental knee arthroplasty: A radiographic analysis of 1000 knees.

PURPOSE: This study aimed to assess phenotypic variation in the coronal plane of knees with anteromedial osteoarthritis using the functional knee phenotype classification, before and after treatment with medial unicompartmental knee arthroplasty (UKA). METHODS: The study comprised 1000 knees of 835 patients (45% females, 55% males, 90% Caucasian) who underwent medial UKA for anteromedial osteoarthritis. Pre and postoperative alignment was evaluated through the hip-knee-ankle angle (HKA), femoral mechanical angle (FMA), and tibial mechanical angle (TMA). Knees were classified according to the functional knee phenotype system which combines limb phenotype (HKA), and femoral and tibial knee phenotypes (FMA and TMA, respectively). Restoration of prearthritic coronal alignment following medial UKA was evaluated by phenotype. RESULTS: Preoperatively, 76 distinct and 25 relevant (prevalence ≥1%) functional knee phenotypes were identified, of which VARHKA 6°VARFMA 3°NEUTMA 0° was the most common (9.4% of knees). The most prevalent limb phenotype, VARHKA 6°, comprised 15 distinct knee phenotypes (FMA and TMA combinations). Postoperatively, 58 distinct and 17 relevant functional knee phenotypes were observed, of which VARHKA 3°NEUFMA 0°NEUTMA 0° had the highest prevalence at 18.3%. Knees with combined tibial and femoral deformities were associated with a lower probability of restoration of prearthritic coronal alignment following medial UKA, compared to knees without extra-articular deformity, or knees with an isolated tibial or femoral deformity. CONCLUSION: Phenotype analysis using the functional knee phenotype system demonstrated a wide diversity of coronal alignment phenotypes among knees with anteromedial osteoarthritis in a predominantly Caucasian population. Following medial UKA, a reduction from 25 preoperative to 17 postoperative relevant phenotypes was observed. Consideration of phenotypic variation can be of importance when aiming to restore prearthritic coronal alignment during medial UKA. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Particulated juvenile cartilage allograft for the treatment of osteochondral lesions of the talus is associated with a high complication rate and a high failure rate at short-term follow-up: A systematic review.

PURPOSE: The purpose of this systematic review was to evaluate the clinical and radiological outcomes together with the complication rates and failure rates at short-term follow-up following particulated juvenile cartilage allograft (PJCA) for the management of osteochondral lesions of the talus (OLT). METHODS: During October 2023, the PubMed, Embase and Cochrane library databases were systematically reviewed to identify clinical studies examining outcomes following PJCA for the management of OLTs. Data regarding study characteristics, patient demographics, lesion characteristics, subjective clinical outcomes, radiological outcomes, complications and failures were extracted and analysed. RESULTS: Twelve studies were included. In total, 241 patients underwent PJCA for the treatment of OLT at a weighted mean follow-up of 29.0 ± 24.9 months. The weighted mean lesion size was 138.3 ± 59.6 mm2 . Prior surgical intervention was recorded in seven studies, the most common of which was microfracture (65.9%). The weighted mean American Orthopaedic Foot and Ankle Society score improved from a preoperative score of 58.5 ± 3.2 to a postoperative score of 83.9 ± 5.3. The weighted mean postoperative magnetic resonance observation of cartilage repair tissue (MOCART) score was 48.2 ± 3.3. The complication rate was 25.2%, the most common of which was allograft hypertrophy (13.2%). Thirty failures (12.4%) were observed at a weighted mean time of 9.8 ± 9.6 months following the index procedure. CONCLUSION: This systematic review demonstrated a moderate improvement in subjective clinical outcomes following PJCA for the treatment of OLT at short term follow-up. However, postoperative MOCART scores were reported as poor. In addition, a high complication rate (25.2%) and a high failure rate (12.4%) at short-term follow-up was observed, calling into question the efficacy of PJCA for the treatment of large OLTs. In light of the available evidence, PJCA for the treatment of large OLTs cannot be currently recommended. LEVEL OF EVIDENCE: Level IV.

Acute clinical evaluation for the diagnosis of lateral ankle ligament injuries is useful: A comparison between the acute and delayed settings.

PURPOSE: To determine the diagnostic value of seven injury history variables, nine clinical tests (including the combination thereof) and overall clinical suspicion for complete discontinuity of the lateral ankle ligaments in the acute (0-2 days post-injury) and delayed setting (5-8 days post-injury). METHODS: All acute ankle injuries in adult athletes (≥18 years) presenting up to 2 days post-injury were assessed for eligibility. Athletes were excluded if imaging studies demonstrated a frank fracture or 3 T MRI could not be acquired within 10 days post-injury. Using standardized history variables and clinical tests, acute clinical evaluation was performed within 2 days post-injury. Delayed clinical evaluation was performed 5-8 days post-injury. Overall, clinical suspicion was recorded after clinical evaluation. MRI was used as the reference standard. RESULTS: Between February 2018 and February 2020, a total of 117 acute ankle injuries were screened for eligibility, of which 43 were included in this study. Complete discontinuity of lateral ankle ligaments was observed in 23 (53%) acute ankle injuries. In the acute setting, lateral swelling had 100% (95% confidence interval [CI]: 82-100) sensitivity, haematoma had 85% (95% CI: 61-96) specificity and the anterior drawer test had 100% (95% CI: 77-100) specificity. In the delayed setting, sensitivity for the presence of haematoma improved from 43% (95% CI: 24-65) to 91% (95% CI: 70-98; p < 0.01) and the sensitivity of the anterior drawer test improved from 21% (95% CI: 7-46) to 61% (95% CI: 39-80; p = 0.02). Clinical suspicion had a positive likelihood ratio (LR) of 4.35 (95% CI: 0.55-34.17) in the acute setting and a positive LR of 6.09 (95% CI: 1.57-23.60) in the delayed setting. CONCLUSIONS: In the acute setting, clinical evaluation can exclude complete discontinuity (e.g., absent lateral swelling) and identify athletes with a high probability of complete discontinuity (e.g., positive anterior drawer test) of the lateral ankle ligaments. In the delayed setting, the sensitivity of common clinical findings increases resulting in an improved diagnostic accuracy. In clinical practice, this study underlines the importance of meticulous clinical evaluation in the acute setting. LEVEL OF EVIDENCE: Level III.

Statistical shape models that predict native glenoid width based on glenoid height are inaccurate in their current form: a cross-sectional study.

BACKGROUND: The extent of measurement errors of statistical shape models that predict native glenoid width based on glenoid height to subsequently determine the amount of anterior glenoid bone loss is unclear. Therefore, the aim of this study was to (1) create a statistical shape model based on glenoid height and width measured on 3-dimensional computed tomography (3D-CT) and determine the accuracy through measurement errors and (2) determine measurement errors of existing 3D-CT statistical shape models. MATERIALS AND METHODS: A retrospective cross-sectional study included all consecutive patients who underwent CT imaging before undergoing primary surgical treatment of traumatic anterior shoulder dislocation between 2007 and 2022 at the Tohoku University Hospital and affiliated hospitals. Patients were included when instability was unilateral and CT scans of both the injured and contralateral uninjured shoulder were available. 3D segmentations were created and glenoid height and width of the injured and contralateral uninjured side (gold standard) were measured. Accuracy was determined through measurement errors, which were defined as a percentage error deviation from native glenoid width (contralateral uninjured glenoid), calculated as follows: measurement error = [(estimated glenoid width with a statistical shape model - native glenoid width) / native glenoid width] × 100%. A linear regression analysis was performed to create a statistical shape model based on glenoid height according to the formula: native glenoid width = a × glenoid height + b. RESULTS: The diagnosis and procedure codes identified 105 patients, of which 69 (66%) were eligible for inclusion. Glenoid height demonstrated a very strong correlation (r = 0.80) with native glenoid width. The linear regression formula based on this cohort was as follows: native glenoid width = 0.75 × glenoid height - 0.61, and it demonstrated an absolute average measurement error of 5% ± 4%. The formulas by Giles et al, Chen et al and Rayes et al demonstrated absolute average measurement errors of 10% ± 7%, 6% ± 5%, and 9% ± 6%, respectively. CONCLUSION: Statistical shape models that estimate native glenoid width based on glenoid height demonstrate unacceptable measurement errors, despite a high correlation. Therefore, great caution is advised when using these models to determine glenoid bone loss percentage. To minimize errors caused by morphologic differences, preference goes to methods that use the contralateral side as reference.

Total Hip Arthroplasty in Teenagers: A Systematic Literature Review.

BACKGROUND: Total hip arthroplasty (THA) in teenagers is generally avoided. Nevertheless, recent THA procedures in a very young patient show improved functional outcomes and implant survival, resulting in lower revision rates. This review aims to present an overview of the available literature on THA in teenagers and to provide evidence to inform caregivers. METHODS: In this systematic review, studies required a primary THA method and a teenage patient population. Studies must report at least one of the following outcome measures: functional outcomes, implant survival, and complications. In addition, demographic and surgical data were collected. RESULTS: Sixteen studies were analyzed, including 2040 patients and 2379 hips, with an average 7.7-year follow-up. The mean patient age was 18 years, with an average revision rate of 11.7%. The overall average relative improvement of the 2 most frequently used patient-reported (functional) outcome measures were 84.3 and 92.3% at the latest follow-up. Prosthesis, or liner loosening, was the cause of revision in 50.2% of the cases. Loosening was the most frequent complication (14.8%), together with prosthesis/liner wear (14.8%). Cementless fixation (70.7%), ceramic-on-ceramic articulation (34.7%), and the posterior surgical approach (82.3%) were the most applied techniques. CONCLUSIONS: The functional outcomes after THA in teenagers improved at follow-up. The average revision rate is relatively high, especially in the pre-1995 studies, with post-1995 studies reporting similar revision rates to the adult patient group. Research to further improve implant survival as well as the ease of revisions in teenagers is needed. LEVEL OF EVIDENCE: Level III-systematic review.

Analyzing Learning Curve Effects: Total Ankle Replacement Design Switch and Long-Term Survival.

Different aspects of the learning curve in Total Ankle Replacement (TAR) have been studied in the short to mid-term, with 30 cases often considered critical. However, its impact on long-term (10 and 15-year) survival remains unclear. Therefore, we retrospectively analyzed 77 consecutive TARs performed by one orthopedic surgeon. The main outcome was long-term survival between cases 1-30 and 31-77 using the Kaplan-Meier with Competing Risk Analyses. Secondarily, we used Moving Average Method with LOESS regression to confirm the learning curve based on the perioperative complications. Thirdly, associations between perioperative complications and operation time on long-term survival were assessed using Cox proportional hazard models. The 10-year survival of cases 1-30 was 89.9% (95% CI 70.4-96.5), and of 31-77, 92.4% (95% CI 7745- 97.5) (p = 0.58). The 15-year survival was 81.8% (95% CI 59.5-91.8) and 74.8% (95% CI 52.4-86.6), respectively (p = 0.97). The long-term survival rate for the TAR that endured perioperative complication was 96.70% (95% CI 90.28-103.12), and for the uncomplicated TAR 87.50% (95% CI 77.12-97.88%) (p=0.24). Operating time nor occurrence of perioperative fractures were significantly associated with long-term survival (p= 0.11 and 0.26, respectively). However, moving average method revealed a significant decreasing trend with a cut-off value of 33 procedures regarding the marginal probability of perioperative osseous complications (p<0.01). In conclusion, surgeons should note a learning curve when adapting arthroplasty procedures. After the prosthesis design switch, the learning curve regarding perioperative osseous complications was confirmed at 33 TAR. The switch did not affect long-term survival.

Automation improves the efficiency of weightbearing CT scan 3D volumetric assessments of the syndesmosis.

BACKGROUND: Weight-bearing CT (WBCT) 3D volumetric measurement has shown promising accuracy for the diagnosis of syndesmotic instability. However, these measurements are rather complex and time-consuming, rendering them a clinically unfavorable option. We hypothesized that automatized measurements would be more accurate and time-efficient than manual ones. METHODS: Thirty cases of intraoperatively confirmed syndesmotic instability along with thirty individuals with no injuries to the ankle joint were recruited as cases and controls, retrospectively. Two observers conducted the manual volumetric measurements two times, at a one-week interval. An automated algorithm for 3D WBCT measurements was developed to conduct the measurements on the axial images. The time spent on each method was recorded. Mann-Whitney U test was used to compare the values between human raters and computers. Inter- and intra-class reliability were calculated. RESULTS: The intra-class correlation coefficient was found to be "excellent" for the automated measurements (0.97) and "good" for the observers (0.75). Similarly, the Cronbach's alpha was shown to be higher for the computer (0.88) than the observers (0.60 and 0.62). The mean time spent on the measurements was different between human raters and the computer-assisted method (p < 0.001). CONCLUSION: Automated volumetric assessment of syndesmosis seems to be a faster and more reliable option than the manual one. We suggest future larger-scale prospective studies conducted under actual clinical circumstances for more definitive conclusions. LEVEL OF EVIDENCE: Retrospective case-control study - Level 3.