Tibial tuberosity-trochlear groove distance is significantly decreased by medial closing wedge distal femoral osteotomy.

PURPOSE: While medial closing wedge distal femoral osteotomy (MCWDFO) has been used to address patella instability combined with valgus malalignment, its impact on patellofemoral parameters remains uncharted. Hence, this study seeks to establish a three-dimensional (3D) planning of MCWDFO and measure its effect on the tibial tubercle - trochlear groove distance (TTTG) through simulation and calculation. METHODS: MCWDFO with a stepwise increment of one-degree varisation (1°-15°) was performed on 3D surface models of 14 lower extremities with valgus malalignment and 24 lower extremities with neutral alignment of the lower limb, resulting in a total of 608 simulations. Anatomic landmarks were employed to measure hip-knee-ankle angle (HKA), TTTG, and femoral torsion for each simulation. A mathematical formula was adopted to calculate TTTG changes following MCWDFO, and subsequently the mean simulated and calculated TTTG values were compared. Following a standardised protocol, MCWDFO was performed without rotational changes. RESULTS: MCWDFO exhibited an almost linear reduction in TTTG, at a rate of approximately -1.05 ± 0.13 mm per 1° of varisation, demonstrating a strong negative correlation (R = -0.83; p < 0.001). Limb alignment did not exert an influence on TTTG change; however, it correlated with tibial plateau width. The mean difference between the simulated and calculated TTTG values amounted to 0.03 ± 0.03 mm per 1° varisation (p < 0.001). CONCLUSION: The TTTG distance is linearly reduced by 1.05 mm for every 1° of varisation within the varus correction range of 0°-15° during MCWDFO. Patients with combined valgus and patellar instability may benefit from MCWDFO due to frequently pathological TTTG. LEVEL OF EVIDENCE: Level III, descriptive laboratory study.

Undersizing of the tibial component in Oxford unicompartmental knee arthroplasty (UKA) increases the risk of periprosthetic fractures.

INTRODUCTION: Tibial periprosthetic fractures (TPF) after unicompartmental knee arthroplasty (UKA) are a rare condition that affects about 1% of cases. Known risk factors include age, sex, body mass index (BMI), and bone density, as well as surgical technique and prosthesis design. The purpose of the study was to determine if undersizing of the tibial component in relation to the femoral component increases the risk of tibial periprosthetic fractures. MATERIAL AND METHODS: Over a 6-year-period 1542 patients with cemented (n = 363) and uncemented (n = 1179) medial UKA were retrospectively evaluated. Tibial periprosthetic fractures were identified and classified, and epidemiologic data were documented at follow-up. Undersizing was defined as a smaller tibial component compared to the femoral implant. The association of potential risk factors for TPF with the incidence of TPF was investigated with binominal logistic regression. RESULTS: Fourteen patients (0.9%) suffered from TPF at a median of 1 month after surgery. The mean follow-up period was 5.9 ± 1.7 years. Fractures were more common in cases with undersized tibial components [odds ratio (OR) 3.2, p < 0.05]. Furthermore, older age (OR 1.1, p < 0.05) and female sex (OR 6.5, p < 0.05) were identified as significant risk factors, while BMI (p = 0.8) and cemented implantation (p = 0.2) had no effect on fracture rate. Revision surgery included open reduction and internal fixation or conversion to total knee arthroplasty. CONCLUSIONS: Undersizing of implant sizes in UKA increases the risk for TPF especially in patients with small tibial implants. Therefore, mismatched implants should be avoided for UKA particularly when risk factors like obesity, older age, or female gender are present. Tibial periprosthetic fractures were successfully treated by open reduction and internal fixation or conversion to total knee arthroplasty.

Patient-Reported Outcomes following Tibial Plateau Fractures: Mid- to Short-Term Implications for Knee Function and Activity Level.

Background: Patients with complex proximal tibial plateau fractures (TPFs) tend to overestimate the prognosis of their injury, potentially due to factors such as a limited understanding, optimism, and the influence of the pain intensity. Understanding the reasons behind this misperception is crucial for healthcare providers to effectively communicate with patients and establish realistic expectations for treatment outcomes. The purpose of this study was to analyze the outcomes of TPFs, with a particular focus on patient-reported outcome measures concerning functional recovery, pain levels, and overall satisfaction with treatment. The authors aim to provide valuable insights into the realistic expectations and potential limitations that patients may encounter during their recovery journey. Methods: In this retrospective single-center study, all surgically treated TPFs between January 2014 and December 2019 with a minimum follow-up of 12 months were included. Several patient-reported outcome measures were obtained, including the International Knee documentation Committee Score (IKDC), Lyholm score, Tegner score, and visual analog scale (VAS) for pain. Fractures were classified according to Schatzker, and then subgrouped into simple (Schatzker I-III) and complex (Schatzker IV-VI) fractures. Results: A total of 54 patients (mean age 51.1 ± 11.9 years, 59.3% female) with a mean follow-up time of 3.9 years were included. Schatzker II fractures were present in 48% (n = 26) of the cases, with Schatzker III in 6% (n = 3), Schatzker IV fractures in 6% (n = 3), and Schatker VI fractures in 41% (n = 22) of the cases. All outcome scores showed a significant improvement between the first year after surgery and the last follow-up (mean: 3.9 years). Simple fractures showed significantly lower patient-reported outcomes when compared to the preinjury state; however, good to excellent results were observed. Patient-reported outcomes of complex fractures showed no significant changes in the study period with good to excellent results. When it comes to the Lysholm score, there were no significant differences in the outcome between simple and complex fractures. Furthermore, there was a return-to-sports rate of 100%, with high rates of changing sporting activity in 25% (simple fractures) and 45% in complex fractures. Conclusions: The data from this study showed that both simple and complex tibial plateau fractures show favorable outcomes at the midterm follow-up, and that injury severity does not correlate with worse results. While patients may tend to overestimate the recovery speed, this research highlights the importance of long-term follow-up, demonstrating a substantial improvement between one year post-surgery and the final evaluation. Return-to-sports rates were high, with adjustments needed for certain activities. However, patients should recognize the need to shift to lower-impact sports and the lengthy recovery process.

Mid-Term Migration Behavior of an Uncemented Proximally Anchored Straight Stem-A Retrospective EBRA Migration Analysis.

BACKGROUND: Aseptic loosening is one of the most-common causes of the failure of cementless stems. Einzel Bild Röntgen Analyse-Femoral Component Analysis (EBRA-FCA) allows the diagnosis of stem migration, which can be considered a factor in predicting implant survival. The current study aimed to present the migration behavior of a tapered proximally anchored straight stem. METHODS: This retrospective study reviewed all consecutive patients who received a cementless CBC straight stem (Mathys AG, Bettlach, Switzerland) between 2005 and 2019. We analyzed the migration pattern using the EBRA-FCA software and reviewed their medical histories. In addition, periprosthetic radiolucency was rated according to the Gruen zones and femoral configuration according to Dorr. RESULTS: A total of 333 stems in 332 patients (female 191; male 141) met our inclusion criteria. The mean age at surgery was 63 (range 21-87) years. Migration analysis by EBRA-FCA showed a mean subsidence of 1.6 mm at final follow-up at 96 months with a maximum noted mean subsidence of 2.0 mm at 72 and 84 months. Dorr Type A showed a tendency of less subsidence than did Dorr Type B and was statistically significant at 6 (p = 0.0396) and 72 months (p = 0.0127). The body mass index (BMI) and increased subsidence were not found to correlate (p > 0.05). For this cohort, the overall femoral revision-free rate was 95.2% and the revision-free rate for aseptic loosening was 99.1%. CONCLUSIONS: The results showed migration behavior in cementless stems with initial increased migration and subsequent secondary stabilization, suggesting an excellent long-term outcome. Stem migration of this tapered proximally anchored stem might be lower in Dorr Type A than in Dorr Type B femurs without being statistically significant at all time points.

Mismatch between Clinical-Functional and Radiological Outcome in Tibial Plateau Fractures: A Retrospective Study.

BACKGROUND: The evaluation of tibial plateau fractures (TPF) encompasses the assessment of clinical-functional and radiological parameters. In this study, the authors aimed to investigate the potential correlation between these parameters by utilizing both the clinical-functional and the modified radiological Rasmussen score. METHODS: In this retrospective monocentric study conducted at a level-I trauma center, patients who underwent surgery between January 2014 and December 2019 due to a TPF were included. The clinical-functional Rasmussen score prior to the injury, at 1-year postoperatively, and during the last follow-up (minimum 18 months) was assessed using a standardized questionnaire. Additionally, the modified radiological Rasmussen score was determined at the 1-year postoperative mark using conventional radiographs in two planes. RESULTS: A total of 50 patients were included in this study, comprising 40% (n = 20) men, and 60% (n = 30) women, with an average age of 47 ± 11.8 years (range 26-73 years old). Among them, 52% (n = 26) had simple fractures (classified according to Schatzker I-III), while 48% (n = 24; according to Schatzker IV-VI) had complex fractures. The mean follow-up was 3.9 ± 1.6 years (range 1.6-7.5 years). The functional Rasmussen score assessed before the injury and at follow-up showed an "excellent" average result. However, there was a significant difference in the values of complex fractures compared to before the injury. One year postoperatively, both the clinical-functional score and the modified radiological score demonstrated a "good" average result. The "excellent" category was more frequently observed in the functional score, while the "fair" category was more common in the radiological score. There was no agreement between the categories in both scores in 66% of the cases. CONCLUSIONS: The data from this retrospective study demonstrated that patients with TPF are able to achieve a nearly equivalent functional level in the medium-term after a prolonged recovery period, comparable to their pre-injury state. However, it is important to note that the correlation between clinical-functional and radiological parameters is limited. Consequently, in order to create prospective outcome scores, it becomes crucial to objectively assess the multifaceted nature of TPF injuries in more detail, both clinically and radiologically.

[Possibilities and limits of intraoperative 2D imaging in trauma surgery]. / Möglichkeiten und Grenzen der intraoperativen 2D-Bildgebung in der Unfallchirurgie.

BACKGROUND: The two-dimensional (2D) imaging represents an essential and cost-effective component of intraoperative position control in fracture stabilization, even in the era of new three-dimensional (3D) imaging capabilities. OBJECTIVE: The aim of the present study, in addition to a current literature review, was to examine whether the intraoperative use of 2D images leads to a quality of fracture reduction comparable to postoperative computed tomographic (CT) analysis including 3D reconstructions. MATERIAL AND METHODS: A comparative retrospective analysis of intraoperative 2D and postoperative 3D image data was performed on 21 acetabular fractures stabilized via a pararectus approach according to an established protocol using the Matta criteria. RESULTS: The assessment of fracture reduction in intraoperative fluoroscopy compared with postoperative CT revealed a difference only in one case with respect to the categorization of the joint step reduction in the main loading zone. CONCLUSION: In the intraoperative use of 2D imaging for fracture treatment it is important to select the correct adjustment planes taking the anatomical conditions into account in order to achieve optimum assessability. In this way, the reduction result can be adequately displayed in fluoroscopy and is also comparable to the postoperative CT control. In addition, depending on the findings, optional intraoperative dynamic fluoroscopic assessment can have a direct influence on the further surgical procedure.

Preoperative Mixed-Reality Visualization of Complex Tibial Plateau Fractures and Its Benefit Compared to CT and 3D Printing.

BACKGROUND: Various studies have shown the benefit of three-dimensional (3D) computed tomography (CT) reconstruction and especially 3D printing in the treatment of tibial plateau fractures (TPFs). This study aimed to investigate whether mixed-reality visualization (MRV) using mixed-reality glasses can provide a benefit for CT and/or 3D printing in planning treatment strategies for complex TPFs. METHODS: Three complex TPFs were selected for the study and processed for 3D imaging. Subsequently, the fractures were presented to specialists in trauma surgery using CT (including 3D CT reconstruction), MRV (hardware: Microsoft HoloLens 2; software: mediCAD MIXED REALITY) and 3D prints. A standardized questionnaire on fracture morphology and treatment strategy was completed after each imaging session. RESULTS: 23 surgeons from 7 hospitals were interviewed. A total of 69.6% (n = 16) of those had treated at least 50 TPFs. A change in fracture classification according to Schatzker was recorded in 7.1% of the cases and in 78.6% an adjustment of the ten-segment classification was observed after MRV. In addition, the intended patient positioning changed in 16.1% of the cases, the surgical approach in 33.9% and osteosynthesis in 39.3%. A total of 82.1% of the participants rated MRV as beneficial compared to CT regarding fracture morphology and treatment planning. An additional benefit of 3D printing was reported in 57.1% of the cases (five-point Likert scale). CONCLUSIONS: Preoperative MRV of complex TPFs leads to improved fracture understanding, better treatment strategies and a higher detection rate of fractures in posterior segments, and it thus has the potential to improve patient care and outcomes.

Mid-Term Results following Traumatic Knee Joint Dislocation.

PURPOSE: Although treatment strategies of knee joint dislocations have evolved, there is still no consensus on the best method and timing. New therapeutic concepts suggest that early one-stage treatment, including suturing and bracing of the cruciate ligaments in acute knee joint dislocation, are leading to improved functional results. This study aimed to evaluate the midterm functional outcome following traumatic knee joint dislocation and to determine whether the outcome is influenced by the surgical management, patient habitus or concomitant injuries. METHODS: In this retrospective single center study, 38 patients with acute Schenck type II to IV knee dislocations were treated over an eight-year period in a level I trauma center. At follow-up, various clinical scores, such as the International Knee Documentation Committee (IKDC) Score, Lysholm Score, and Tegner Activity Scale (TAS), and individual questions about rehabilitation and activity levels of 38 patients were evaluated. RESULTS: Mean follow-up was 5.5 ± 2.7 years. The mean IKDC Score was 65.6 ± 15.7 points, the average Lysholm Score was 70.5 ± 16.4 points and the median TAS was 4 (0-7), resulting in a loss of activity of 2 (range 0-6) points. There was no significant difference between a one-stage treatment compared to a two-stage approach. Ligament reconstruction of the ACL in a two-stage approach was required in only 33.3%. Further operations (early and late) were performed in 37% of cases. Being overweight was associated with more complications and worse outcomes, and external fixation with arthrofibrosis. CONCLUSIONS: Knee dislocation is a severe trauma that often leads to a prolonged loss of function and increased knee pain over years, affecting the patient's activity. Clinical outcome is influenced significantly by concomitant injuries. Severe cases with initial external fixation are associated with a higher risk of knee stiffness and should be considered during rehabilitation. Obese patients present a challenge due to higher complication rates and lower postoperative knee function. LEVEL OF EVIDENCE: Retrospective single center study, level III.

Viscoelasticity and histology of the human cartilage in healthy and degenerated conditions of the knee.

BACKGROUND: There are many studies on osteoarthritis, but only a few studies deal with human arthrosis, comparing the mechanical properties of healthy and diseased samples. In most of these studies, only isolated areas of the tibia are examined. There is currently only one study investigating the complete mapping of cartilage tissue but not the difference between instantaneous modulus (IM) in healthy and diseased samples. The aim of this study is to investigate the relationship between the biomechanical and histological changes of articular cartilage in the pathogenesis of osteoarthritis. METHODS: The study compared 25 tibiae with medial gonarthrosis and 13 healthy controls. The IM was determined by automated indentation mapping using a Mach-1 V500css testing machine. A grid was projected over the sample and stored so that all measurements could be taken at the same positions (100 ± 29 positions across the tibiae). This grid was then used to perform the thickness measurement using the needle method. Samples were then taken for histological examinations using a hollow milling machine. Then Giemsa and Safranin O staining were performed. In order to determine the degree of arthrosis according to histological criteria, the assessment was made with regard to Osteoarthritis Research Society International (OARSI) and AHO scores. RESULTS: A significant difference (p < 0.05) could be observed in the measured IM between the controls with 3.43 ± 0.36 MPa and the samples with 2.09 ± 0.18 MPa. In addition, there was a significant difference in IM in terms of meniscus-covered and meniscus-uncovered areas. The difference in cartilage thickness between 2.25 ± 0.11 mm controls and 2.0 ± 0.07 mm samples was highly significant with p < 0.001. With regard to the OARSI and AHO scores, the samples differed significantly from the controls. The OARSI and AHO scores showed a significant difference between meniscus-covered and meniscus-uncovered areas. CONCLUSIONS: The controls showed significantly better viscoelastic behavior than the arthrotic samples in the measured IM. The measured biomechanical values showed a direct correlation between histological changes and altered biomechanics in gonarthrosis.