Lateral Femoral Condyle Allograft in the Treatment of Elbow Capitellar Avascular Necrosis: A Case Report.

CASE: A 27-year-old woman developed capitellar osteonecrosis after long-term corticosteroid use to treat non-Hodgkin lymphoma. She underwent an osteochondral reconstruction using a lateral femoral condyle (LFC) allograft. This graft was selected because it has a similar radius of curvature to the capitellum. The patient had osseous integration, painless, near full range of motion of her elbow 6 months postoperatively and good shoulder function 1.0 year postoperatively. CONCLUSION: The LFC allograft should be considered a viable option in treating capitellar osteonecrosis.

Does the intercondylar approach provide a better outcome for chondroblastoma of the distal femur in skeletally immature patients?

Aims: The epiphyseal approach to a chondroblastoma of the intercondylar notch of a child's distal femur does not provide adequate exposure, thereby necessitating the removal of a substantial amount of unaffected bone to expose the lesion. In this study, we compared the functional outcomes, local recurrence, and surgical complications of treating a chondroblastoma of the distal femoral epiphysis by either an intercondylar or an epiphyseal approach. Methods: A total of 30 children with a chondroblastoma of the distal femur who had been treated by intraregional curettage and bone grafting were retrospectively reviewed. An intercondylar approach was used in 16 patients (group A) and an epiphyseal approach in 14 (group B). Limb function was assessed using the Musculoskeletal Tumor Society (MSTS) scoring system and Sailhan's functional criteria. Results: At final follow-up, the mean MSTS score was 29.1 (SD 0.9) in group A and 26.7 (SD 1.5) in group B (p = 0.006). According to Sailhan's criteria, the knee function was good and fair in 14 (87.5%) and two (12.5%) patients of group A, and eight (57.1%) and six (42.9%) patients of group B, respectively (p = 0.062). The lesion had recurred in one patient (6.2%) in group A and four patients (28.6%) in group B. Limb shortening > 1 cm was recorded in one patient (6.2%) from group A and six patients (42.8%) from group B. Joint degeneration was noted in one patient from group A and three patients from group B. Conclusion: An intercondylar approach to a chondroblastoma of the middle two-quarters of the distal femoral epiphysis results in better outcomes than a medial or lateral epiphyseal approach: specifically, better limb function, a lower rate of recurrence, and a lower rate of physeal damage and joint degeneration.

The effect of caponization on tibia bone histomorphometric properties of crossbred roosters.

The negative effect of caponization on the structural, geometric and mechanical parameters of femur and tibia has been shown in a few studies. Nevertheless, its influence on tibia bone microarchitecture is still largely unknown. Therefore, this study aimed to assess the effect of castration on the microstructural parameters of the trabecular and compact bone of tibia bone in crossbred chickens. The experiment involved 96 roosters derived from crossing Yellowleg Partridge hens ([Formula: see text]-33) and Rhode Island Red cockerels (R-11) fattened until the 16th, 20th and 24th week of life. Animals were randomly divided into 2 groups of 48 each. Group I (control) consisted of intact roosters and group II (experimental) consisted of birds subjected to caponization at the 8th week of age. The castration surgery had no influence on some properties within compact bone such as osteon diameter On.Dm, osteon perimeter On.Pm, osteon area On.Ar, osteocyte lacunar number Ot.Lc.N, osteon bone area On.B.Ar, osteon wall thickness On.W.Th as well as thick-mature collagen content in all analyzed age groups of animals. Nevertheless, our results demonstrate that castration caused a decrease of Haversian canal area Hc.Ar, osteocyte lacunar area Ot.Lc.Ar and osteocyte lacunar porosity Ot.Lc.Po among the 16-week-old birds, decrease of Haversian canal perimeter Hc.Pm and increase of fraction of bone area On.B.Ar/On.Ar among 16- and 24-week-old individuals and also an increase of osteocyte lacunar density Ot.Lc.Dn in the osteons of the oldest roosters. Additionally, some microstructural parameters of trabecular bone show the negative effect of caponization. The youngest 16-week-old capons were characterized by thinnin the trabecular in the epiphysis part of tibia. Moreover, in the case of 24-week-old, there is an increase in the trabecular separation Tb.Sp with simultaneous decrease of trabecular number Tb.N compared to roosters, which may suggest the increase of the bone resorption among the oldest individuals. The increased bone turnover in the epiphysis part of the tibia bone also indicates changes in the collagen fibers distribution, where among 20-week-old animals there is a decrease in the content of immature thin collagen fibers with simultaneous increase in the content of mature thick collagen fibers. Furthermore, among the oldest 24-week-old individuals we can observe the increased thick-to-thin collagen ratio, which may be a sign of slowing down in bone formation.

Corrective Osteotomy and Ligamentous Reconstruction in a Neglected Elbow Dislocation with Radial Neck Malunion: A Case Report.

CASE: Neglected elbow dislocation and radial neck malunion frequently result in chronic pain, instability, and early arthrosis. These complications are best prevented by early treatment with open reduction, corrective osteotomy, and ligament reconstruction, followed by early supervised physiotherapy. We present a peculiar case with neglected complex elbow dislocation and radial head malunion. In this case, we performed an open reduction of the elbow joint and radial neck corrective osteotomy, medial collateral ligament, annular ligament reconstruction, and lateral collateral ligament repair. CONCLUSION: Neglected complex elbow dislocations require reconstruction of both ligamentous and osseous structures to achieve a good functional outcome.

Natural history of Wolcott-Rallison syndrome: A systematic review and follow-up study.

BACKGROUND AND AIMS: To systematically review the literature for reports on Wolcott-Rallison syndrome, focusing on the spectrum and natural history, genotype-phenotype correlations, patient and native liver survival, and long-term outcomes. METHODS: PubMed, Livio, Google Scholar, Scopus and Web of Science databases were searched. Data on genotype, phenotype, therapy, cause of death and follow-up were extracted. Survival and correlation analyses were performed. RESULTS: Sixty-two studies with 159 patients met the inclusion criteria and additional 30 WRS individuals were collected by personal contact. The median age of presentation was 2.5 months (IQR 2) and of death was 36 months (IQR 50.75). The most frequent clinical feature was neonatal diabetes in all patients, followed by liver impairment in 73%, impaired growth in 72%, skeletal abnormalities in 59.8%, the nervous system in 37.6%, the kidney in 35.4%, insufficient haematopoiesis in 34.4%, hypothyroidism in 14.8% and exocrine pancreas insufficiency in 10.6%. Episodes of acute liver failure were frequently reported. Liver transplantation was performed in six, combined liver-pancreas in one and combined liver-pancreas-kidney transplantation in two individuals. Patient survival was significantly better in the transplant cohort (p = .0057). One-, five- and ten-year patient survival rates were 89.4%, 65.5% and 53.1%, respectively. Liver failure was reported as the leading cause of death in 17.9% of cases. Overall survival was better in individuals with missense mutations (p = .013). CONCLUSION: Wolcott-Rallison syndrome has variable clinical courses. Overall survival is better in individuals with missense mutations. Liver- or multi-organ transplantation is a feasible treatment option to improve survival.

The transphyseal osteotomy for the slipped proximal tibial epiphysis in tibia vara.

This study aimed to describe a novel transphyseal osteotomy (TPO) for acute deformity correction in children with bilateral tibia vara and the atraumatic 'slipped proximal tibial epiphysis' (SPTE) entity. We described the clinical and radiological findings in five children (10 limbs) with tibia vara that were treated with the TPO. The criteria for the SPTE were met in nine (9/10) cases. The surgical technique and short-term results of the TPO are reported. The median age was 9 years (range, 6-9), with obesity (BMI > 95th centile) present in all children. The medial tibial plateau was not significantly depressed (the median angle of depression of the medial plateau measured 30° (range, 20°-32°). The mean medial proximal tibial angle of 33° (range, 8°-71°) was corrected to 82° (range, 77°-86°), the mean anatomic posterior proximal tibial angle of 48° (range, 32°-70°) was corrected to 72° (range, 61°-86°), and the median internal tibial rotation of 45° (range, 20°-50° internal rotation) was corrected to neutral rotation (range, 10° internal-10° external rotation). There were two complications: one case of recurrent deformity and one case of intra-articular extension of the osteotomy. We describe a novel TPO that aims to simultaneously correct all aspects of the deformity, stabilise the physis, and prevent recurrence through epiphysiodesis. Further research is required to determine its efficacy and safety. The atraumatic SPTE appears to represent a specific morphological presentation in tibia vara. Level of evidence: 4.

Periosteal chondroblastoma of the femoral neck: two cases and a review of the literature.

Chondroblastoma is a rare benign cartilaginous tumor mostly confined to the epiphyses and apophyses. Cases outside the epiphyseal region are exceedingly rare. Extramedullary chondroblastomas are exceptional; to our knowledge, only two cases qualified as "periosteal chondroblastoma" have been described in the literature. We report two cases of metaphyseal periosteal chondroblastoma both located on the inferior surface of the femoral neck. Both cases were paucicellular with an unusual dense sclerotic reaction. The diagnosis of chondroblastoma was supported by the expression of histone 3.3, K36M mutant in tumor cells.

Spontaneous improvement of bilateral clinodactyly of the little finger with trapezoidal phalanx: a case report with a 15-year follow-up.

Clinodactyly can be produced by a longitudinal epiphyseal bracket that generates either a 'delta' or 'trapezoidal' phalanx. We present a case with a 15-year follow-up of bilateral clinodactyly of the little finger, to emphasize a 'wait-and-see' approach as self-remodelling of his phalanges occurred during growth.

Pediatric primary lymphoma of bone in epiphysis case report.

Primary lymphoma of the bone (PLB) is a rare entity, with a majority of pediatric cases presenting in the metaphysis of long bones. There have been only seven reported cases to date of pediatric lymphoma of the bone arising from the epiphysis, of which only two have been described in the proximal tibia. We report a pediatric case of PLB in the tibial epiphysis which presented initially with knee pain. Imaging was performed with X-ray, MRI, CT, and PET-CT with bone biopsies revealing diffuse large B-cell lymphoma. This patient also showed a second, synchronous lesion in the left iliac bone, which was also biopsy proven to diffuse large B-cell lymphoma. Lymphoma in the epiphysis for children is rare and often confused with infectious etiologies or other types of tumors. Misdiagnosis may result in inappropriate treatment and possible progression of the disease, thus making early identification important to initiate therapy.

Stabilisation of femoral capital physeal fractures using transcervical pinning in cats: 19 cases (2014-2022).

OBJECTIVES: To report the short-term clinical and radiographic outcomes in cats with femoral capital physeal fractures stabilised with transcervical pinning. MATERIALS AND METHODS: Medical records of cats diagnosed with femoral capital physeal fractures and treated with transcervical pinning were reviewed. The collected data included signalment, weight, time from lameness to surgery, reported trauma, affected side, concomitant orthopaedic injuries, radiographs, osteoarthritis, femoral neck osteolysis, proximal femoral epiphysis to femoral neck ratio, fracture reduction, implants, complications and clinical evaluation results. An owner questionnaire was used for long-term follow-up. RESULTS: Nineteen cats with a total of 21 fractures met the inclusion criteria. Fifteen of the 19 cats showed no signs of lameness at the 1-month follow-up. Major and catastrophic complications occurred in 9.5% and 23.8% of the fractures, respectively. All catastrophic complications occurred in fractures with a high preoperative osteolysis grade (2 or 3). CLINICAL SIGNIFICANCE: In our study, transcervical pinning was found to be a reliable fixation method for the treatment of femoral capital physeal fractures in cats with minimal preoperative femoral neck osteolysis. High rates of implant failure with loss of fracture reduction were observed in cats with high-grade preoperative osteolysis.

Do metastatic volumes measured in breast cancer patients with bone metastases correlate with the numbers of skeletal and extraskeletal events?

OBJECTIVES: The study aimed to investigate the relationship between metastatic volume measurement, skeletal-related events, and survival in women diagnosed with breast cancer and bone metastases. PATIENTS AND METHODS: This retrospective study was conducted with 82 female breast cancer patients (mean age: 53±14.3 years; range, 23 to 87 years) diagnosed, treated, and followed up between January 2005 and December 2019. The collected data included information on metastasis sites and the presence of skeletal-related events. Metastatic volume was measured in two ways: the number of metastases (high to low) and their localization (the first, second, and third groups). The first group consisted of vertebrae, ribs, sternum, and calvarial bones; the second group included scapula, clavicle, proximal humerus, and proximal femur regions; the third group consisted of femur and humerus diaphyseal and distal regions, as well as metastasis regions in other long bones. RESULTS: Sixty-three (76.8%) patients were diagnosed with ductal carcinoma. Half of the patients had bone metastases at the time of initial diagnosis, while 62 (75.6%) experienced skeletal-related events, with at least three events occurring in 30 (36.6%) patients. Bone pain was the most common skeletal-related event. No correlation was found between metastatic volume measurement based on the localization of bone metastases and the number of bones and the occurrence of skeletal-related events (p>0.05 for each). Patients' survival time spanned from one to 231 months (median: 56.8 months) from their first diagnosis. Patients with high metastatic volume, those in the third group, those whose pelvis and lung were involved, and elderly patients had a shorter survival time (p<0.05 for each). CONCLUSION: The study indicates that measuring metastatic volume may be a critical factor in evaluating the survival of breast cancer patients with bone metastases. Future prospective and randomized controlled studies can explore the potential of this measurement to create practical clinical tools.

Anterior Distal Femoral Hemiepiphysiodesis in Children With Fixed Knee Flexion Deformities: Does Screw Position Matter?

BACKGROUND: Anterior distal femoral hemiepiphysiodesis (ADFH) using 2 percutaneous screws is an effective technique for the treatment of fixed knee flexion deformities in children with neuromuscular disorders. The role of sagittal screw position on the outcome of the procedure is unknown. METHODS: This is a retrospective case series of patients who underwent ADFH at a single pediatric hospital from 2013 to 2020. Radiographs were evaluated for sagittal screw position and the associated change in lateral distal femoral physeal angle over time. The position of the 2 screws was classified as either being both in the anterior third of the physis (AA), one screw in the anterior third and the other screw in the middle third (AM), or both screws in the middle third of the physis (MM). RESULTS: The study population included 68 knees in 36 patients. The mean physeal angle at the time of surgery was 93 degrees (SD 4.0 degrees), which increased to 102.4 degrees (SD 5.7 degrees) at 12 months, for a change of 9.4 degrees ( P <0.001). At 24 months, the mean physeal angle was 104.6 degrees (SD 6.3 degrees) for a further change of 2.9 degrees ( P <0.001). When stratified by screw position all screw configurations resulted in an increase in the physeal angle at 12 months. At the 24-month follow-up, the physeal angle in knees with AA screws continued to increase another 3.5 degrees ( P <0.05), there was a minimal change in knees with AM screws (1.47°, P >0.05) and knees with MM screws saw a reversal of physeal angle change (-7.1 degrees, P <0.05). CONCLUSIONS: ADFH using percutaneous screws results in an increase in the lateral distal femoral physeal angle. The rate of correction is largest in the first 12 months after the procedure. As such, this procedure should be considered in patients with less than 2 years of growth remaining. However, initial screw positioning influences the amount of change over time, and close postoperative surveillance until physeal closure is essential for all patients. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Combined Lateral Closing and Medial Opening-Wedge Proximal Humerus Osteotomy in an Adolescent with Extreme Varus Deformity: A Case Report.

CASE: This report describes the case of an athletic 12-year-old boy who presented with a 64° left proximal humeral varus angulation deformity and physeal bar secondary to multiple operations for a proximal humeral metaphyseal cystic lesion and pathologic fracture. Using a combined lateral closing and medial opening-wedge osteotomy, a 68° valgus correction was achieved with excellent clinical and functional outcomes at 16-month follow-up. Forward flexion increased from 120 to 170° preoperatively to postoperatively while abduction improved from 110° preoperatively to 170° postoperatively. CONCLUSION: A combined lateral closing and medial opening-wedge osteotomy of the proximal humerus can successfully treat cases of extreme proximal humerus varus in the growing shoulder where unilateral or dome osteotomies are not suitable.

Comparison of three radiographic assessment methods for detecting slipped capital femoral epiphyses in cats: Klein's line, modified Klein's line and the S-sign.

OBJECTIVES: The aim of the present study was to investigate whether diagnostic assessment methods used on radiographs in humans with slipped capital femoral epiphysis (SCFE) can be used in cats. METHODS: The ventrodorsal (VD) extended-leg and VD frog-leg pelvic radiographs of 20 cats with SCFE without fully displaced femoral capital epiphyses (FCE), eight cats with fully displaced FCE and five control cats with normal pelvic anatomy were assessed by five observers on two separate occasions 3 months apart. The Klein's line and modified Klein's line were assessed on each VD extended-leg radiograph, and the S-sign was assessed on each VD extended-leg and VD frog-leg radiograph. RESULTS: Excluding cases of fully displaced FCE, the S-sign on the VD frog-leg radiographs more accurately diagnosed SCFE than the S-sign on the VD extended-leg radiographs and the Klein's line (92.4% vs 88.8% vs 60.6%, respectively), and had the greatest sensitivity (93.9% vs 79.2% vs 30.6%, respectively). The S-sign on the VD extended-leg radiographs had greater specificity than the Klein's line and S-sign on the VD frog-leg radiographs (99.2% vs 97.9% vs 90.9%, respectively). The modified Klein's line detected SCFE in 40.2% of cases that were negative for the Klein's line. CONCLUSIONS AND RELEVANCE: The S-sign in both VD extended-leg and VD frog-leg views successfully detected SCFE in cats and can be used to increase early diagnosis and treatment in cats with SCFE that have only subtle radiographic changes.

Spatial heterogeneity of bone marrow endothelial cells unveils a distinct subtype in the epiphysis.

Bone marrow endothelial cells (BMECs) play a key role in bone formation and haematopoiesis. Although recent studies uncovered the cellular taxonomy of stromal compartments in the bone marrow (BM), the complexity of BMECs is not fully characterized. In the present study, using single-cell RNA sequencing, we defined a spatial heterogeneity of BMECs and identified a capillary subtype, termed type S (secondary ossification) endothelial cells (ECs), exclusively existing in the epiphysis. Type S ECs possessed unique phenotypic characteristics in terms of structure, plasticity and gene expression profiles. Genetic experiments showed that type S ECs atypically contributed to the acquisition of bone strength by secreting type I collagen, the most abundant bone matrix component. Moreover, these cells formed a distinct reservoir for haematopoietic stem cells. These findings provide the landscape for the cellular architecture in the BM vasculature and underscore the importance of epiphyseal ECs during bone and haematopoietic development.

Nonossifying Fibroma Involving Epiphysis of Long Bone-Case Report and Review of the Literature.

Nonossifying fibroma (NOF) is a common benign bone neoplasm and is usually observed in the first 2 decades of life. Most NOFs occur in the metaphysis of long bones of the lower extremities and migrate toward the diaphysis during skeletal maturation. Epiphyseal involvement by NOF has been rarely reported, with only one case found in the English literature. The authors report the second case of NOF involving the epiphysis of a long bone, the proximal tibia of a 21-year-old woman. Clinicians and pathologists should be aware of the rare possibility of epiphyseal involvement of long bones by this condition. Pathologists should select appropriate immunohistochemistry markers to rule out alternative diagnoses.

The effect of oral hydroxychloroquine on chondral defect: An experimental study.

OBJECTIVES: This study aims to evaluate the time- and dose-dependent effects of oral hydroxychloroquine (HCQ) on focal full-thickness knee chondral defect healing in a rabbit model. MATERIALS AND METHODS: Cartilage defects of 4x4 mm2 were created on both medial femoral condyles of 24 New Zealand rabbits. The rabbits were divided into six groups (A-F) according to HCQ administration and sacrifice time: A (three-week control) and B (six-week control) received no additional interventions; C (20 mg/kg HCQ, three weeks); D (20 mg/kg HCQ, six weeks); E (40 mg/kg HCQ, three weeks); and F (40 mg/kg HCQ, six weeks). Osteochondral specimens were evaluated macroscopically, histologically, and immunohistochemically. The terminal deoxynucleotidyl-transferase (TdT)-mediated dUTP nick end labeling (TUNEL) method was used to detect apoptotic cells. RESULTS: The International Cartilage Repair Society (ICRS) scores were significantly higher in the experimental groups than in the controls (p<0.001). The Wakitani scores in Group D showed a significant improvement compared to those in Group B (p<0.01). The 20 mg/kg HCQ treatment groups showed better recovery than the controls (p<0.01). High-dose HCQ (40 mg/kg) treatment significantly reduced the intensity of collagen type 2 immunoreactivity compared to that in the groups receiving 20 mg/kg of HCQ (p<0.01). Collagen type 2 expression in Group F was significantly lower than that in Group D (p<0.01). There were more TUNEL-positive cells in the repair sites of Groups E and F than in the lower-dose experimental groups and untreated experimental groups (p<0.001). CONCLUSION: A low dose of HCQ improved cartilage repair, while higher doses of HCQ exerted a negative effect on cartilage regeneration in rabbits. In the presence of defective cartilage, the use of HCQ at an appropriate dose and time is important for cartilage health.

MR features of primary bone lymphoma in children.

BACKGROUND: Primary lymphoma of bone is an uncommon non-Hodgkin lymphoma. Magnetic resonance imaging (MRI) features of primary lymphoma of bone in children are not well described. OBJECTIVE: To identify typical MRI characteristics of pediatric primary lymphoma of bone at diagnosis and following treatment. MATERIALS AND METHODS: Two pediatric radiologists retrospectively reviewed all imaging studies of 10 patients with biopsy-proven primary lymphoma of bone at presentation and after treatment. Anatomic location, number of sites, location within bone (epiphyseal, metaphyseal, diaphyseal), T1-weighted imaging margins, soft tissue mass, T2-weighted imaging appearance and enhancement pattern (homogeneous, heterogeneous, infarct-like), soft tissue edema, cortical disruption, and regional lymph nodes as seen on MRI as well as radiographic and positron emission tomography (PET) findings were recorded. Pathologic results, treatment plans, and outcomes at follow-up as detailed in the medical record were tabulated. RESULTS: Of 10 patients, age at diagnosis 8-17 years, median 15 years, 4 (40%) had multifocal disease. MRI revealed 20 total lesions in the 10 patients with femoral lesions most common, being present in 7 (70%) of patients. Eight (80%) patients had at least one lesion around the knee. Eight (80%) patients had 1 or more lesions involving an epiphysis and 5 (50%) had at least 1 lesion confined to the epiphysis. Seven (70%) showed infarct-like appearance on T2-weighted imaging; 7 (88%) of the 8 patients with post-contrast imaging had infarct-like enhancement. Six (60%) had sharp T1 margins, 3 (30%) had cortical disruption, 8 (80%) had at least mild soft tissue edema, and 1 (10%) had soft tissue mass. Three (30%) had at least 1 PET-positive regional lymph node. At follow-up (range 1-108 months, median 4.3 months), all had residual osseous abnormality on MRI with 6 (60%) maintaining an infarct-like or combination of infarct-like and T2 hyperintense appearance. CONCLUSION: Our results in this series of pediatric primary lymphoma of bone identified several frequent MR imaging features. Multifocality, epiphyseal involvement (especially about the knee), infarct-like enhancement pattern, sharp T1 margins, and surrounding soft tissue edema should raise suspicion for primary lymphoma of bone. Following treatment, residual osseous abnormality is expected on MRI.

Review of minimally invasive surgical procedures for assessment and treatment of medial coronoid process disease.

OBJECTIVE: To summarize the current peer-reviewed publications on minimally invasive surgery (MIS) for medial coronoid process disease (MCPD) in dogs. STUDY DESIGN: Invited review. METHODS: Pubmed, CAB Abstracts and Scopus databases were utilized for literature review (1990-2023). RESULTS: More than 60 papers have been published that involve MIS evaluation or treatment of MCPD. Six prospective trials incorporated quantitative gait analysis evaluating outcome following MCPD debridement, of which three included a control group. Whilst case numbers were limited, all studies employing a control group failed to demonstrate superiority of surgery over nonsurgical management. Of three studies employing gait analysis and no control group, all documented some improvement in function compared to pretreatment lameness. Multiple studies document progression of osteoarthritis in dogs following MCPD debridement although this may not be synonymous with worsened function. Subtotal coronoid osteotomy (SCO) is described as an alternative to MCP fragment removal, although the long-term biomechanical consequences are currently unclear and quantitative data on the efficacy of this treatment in isolation for MCPD is awaited. CONCLUSION: Arthroscopy of the canine elbow joint is a safe means by which to evaluate MCP pathology. Quantitative longitudinal analysis of outcome following minimally invasive surgery for MCPD is required. Correlation with clearly defined subclassification inclusion criteria such as age, incongruity and the precise arthroscopic findings in each case are required to more accurately differentiate any superiority of surgery over nonsurgical management for this disease.

Tibial bone defect prediction based on preoperative artefact-reduced CT imaging is superior to standard radiograph assessment.

PURPOSE: The purpose of this study was to evaluate the accuracy of preoperative CT-based Anderson Orthopaedic Research Institute (AORI)-grading and to correlate Computed tomography (CT)-based volumetric defect measurements with intraoperative AORI findings. METHODS: 99 patients undergoing revision total knee arthroplasty (rTKA) with preoperative CT-images were identified in an institutional revision registry. CT-image segmentation with 3D-Slicer Software was used to create 3D tibial bone defects which were then graded according to the AORI-classification. The AORI classification categorizes tibial defects into three types: Type I has healthy cortical and cancellous bone near the joint line, Type II involves metaphyseal bone loss affecting one or both condyles, and Type III indicates deficient metaphyseal bone with distal defects and potential damage to the patellar tendon and collateral ligament attachments. These 3D-CT gradings were compared to preoperative X-ray and intraoperative AORI grading. The Friedman test was used to investigate differences between AORI values of each measurement method. Volumetric 3D-bone defect measurements were used to investigate the relationship between AORI classification and volumetric defect size in the three anatomic zones of the tibia. RESULTS: Substantial agreements between preoperative 3D-CT AORI and intraoperative AORI (kappa = 0.663; P < 0.01) and fair agreements between preoperative X-ray AORI and intraoperative AORI grading (kappa = 0.304; P < 0.01) were found. Moderate correlations between volume of remaining bone and intraoperative AORI grading were found in epiphysis (rS = - 0.529; P < 0.001), metaphysis (rS = - 0.557; P < 0.001) and diaphysis (rS = - 0.421; P < 0.001). Small volumetric differences between AORI I vs. AORI II defects and relatively large differences between AORI II and AORI III defects in each zone were detected. CONCLUSION: Tibial bone defect prediction based on preoperative 3D-CT segmentation showed a substantial agreement with intraoperative findings and is superior to standard radiograph assessment. The relatively small difference in defect volume between AORI I, IIa and IIb suggests that updated CT-based classifications might hold benefits for the planning of rTKA. LEVEL OF EVIDENCE: Retrospective Cohort Study; III.