Surgical Epicondylar Axis of the Knee and Its Relationship to the Axial Tibia Alignment in Knee Osteoarthritis: The Concept of Proximal Twist Tibia

The proximal tibia and distal femur are intimately linked with the biomechanics of the knee and they are to be considered in total knee arthroplasty (TKA). The aim of the present study was to evaluate the proximal tibial torsion (PTT) in relation to surgical epicondylar axis (SEA) in a healthy cohort and a pathological cohort affected by knee osteoarthritis (OA). We retrospectively analyzed computed tomography of OA knee of 59 patients before they underwent TKA and nonarthritic knee of 39 patients as control. Posterior condylar angle (PCAn), femoral tibial torsion (SEA-proximal tibial condyle [PTC] and SEA-PTT), PTT (PTC-PTT and posterior condylar axes [PCAx]-PTC), and distance between tibial tuberosity and the trochlear groove (TT-TG) were measured. No differences were found for gender, age, TT-TG, and PCAn angles. Statistically significant differences were found for all the other angles considered. Significant correlation was found between tibial torsion and SEA-PTT angles, between PCAx-PTC and SEA-PTC, between SEA-PTT and SEA-PTC, and between PCAx-PTC and SEA-PTT. All measures, except TT-TG and PCAn angles, showed high validity (area under the curve [AUC] > 75%) in associating with OA, with SEA-PTT displaying the highest validity with an AUC of 94.38%. This is the first study to find significant differences in terms of proximal tibia geometry and anatomy between nonarthritic and OA knees. From our results, we reported that OA group was characterized by a greater internal rotation of tibia with respect to SEAs compared with control group. Since the design of the study cannot evaluate a cause–effect relationship, further studies need to be performed to assess the potential implications of these anatomic differences for knee OA and arthroplasty surgeries.

Anatomic Rotational Relationship of Distal Femur in Indian Population and its Implication in Total Knee Arthroplasty: A Magnetic Resonance Imaging Based Study

Background Bony landmarks for referencing distal femoral rotation may differ with ethnic populations. The study aims to find out the relationship of the bony landmarks of distal femur for rotational alignment of femoral component in total knee arthroplasty in Indian population and compare it with other ethnic groups. Methods Rotational relationship of distal femoral bony landmarks was studied using magnetic resonance images of 141 knees. The condylar twist angle (CTA), Whiteside's-posterior condylar axis angle (WL/PCL), Whiteside's-anatomical epicondylar angle (WL/A-EA) and difference between the two epicondylar axes (S-EA/A-EA) were measured. The effect of gender, side and age of these relationships was analyzed. Results The mean CTA, WL/A-EA/WL/PCL and A-EA/S-EA was found to be 5.59 ± 2°, 89.38 ± 2.66°, 5.44 ± 2.88°, 3.11 ± 0.54° respectively. A-EA/S-EA was found to be lower in younger population as compared to the older population. Rest none of the variables showed any significant difference when compared against age, sex or side. Conclusion The posterior condylar axis was 5.59˚ externally rotated in relation to clinical epicondylar axis. About 2.5° of added external rotation is required in jigs using the conventional 3° of inbuilt external rotation, if clinical epicondylar axis is taken as reference for apt placement of the femoral component.

Three-dimensional morphometric differences of resected distal femurs and proximal tibias in osteoarthritic and normal knees

Background There is a paucity of data concerning the morphological differences of resected distal femurs and proximal tibias in osteoarthritic (OA) and normal knees. The objective of this study was to determine whether morphometric differences in the surfaces of resected distal femurs and proximal tibias exist between OA and normal knees in a Chinese population. Methods Ninety-four OA knees and ninety-five normal knees were evaluated in Chinese individuals. Computed tomography was used to measure the femoral mediolateral (fML), medial anteroposterior (fMAP), lateral anteroposterior (fLAP), medial condylar width (fMCW), lateral condylar width (fLCW), medial posterior condylar curvature radii (fMCR), lateral posterior condyle curvature radii (fLCR), fML/fMAP aspect ratio, tibial mediolateral (tML), middle anteroposterior (tAP), medial anteroposterior (tMAP), and lateral anteroposterior (tLAP) tML/tMAP aspect ratio to determine the morphologic differences between OA and normal knees. Results The average fMCW and tMAP dimensions of OA knees were larger than those of normal knees in both male and female (p <0.05). The fMAP/fML aspect ratio and tMAP/tML aspect ratio were also significantly different in both sexs (p <0.05). OA knees have an oval-shaped distal femur with a wider ML length and more spherical-shaped proximal tibiae with relatively narrow ML dimensions. Conclusions The study revealed the morphological differences in fMCW, tMAP, fMAP/fML and tMAP/tML between OA and normal knees in both males and females. These findings may provide guidelines that can be used to design better knee implants that are more size-matched for OA knees.

Treatment of patients with complicated fractures of the distal humerus using the fixators of limited-contact multiplanar osteosynthesis

Treatment of distal humerus fractures is a complex problem in traumatology. The result of treatment depends on the choice of fixator according to the fracture area. Objective. To improve the techno­logy of treatment in patients with complicated distal humerus fractures with fixators of small contact and multiplanar osteosynthesis and to evaluate its efficacy. Methods. 39 patients were treated for the period 2000–2020 with distal humerus nonunion (types 12-B1, 12-C1, 12-C2) and 23 patients with complicated above- and transcondylar humerus fractures (types 13-A2, 13-C1, 13-C2). Fixation of bone fragments of the distal humerus was made with device for fixation (Patent 17502 UA). It is a shaped plate with a groove on which half rings with threaded holes are stabilized. For the osteosynthesis of above- and transcondylar humerus fractures we used V-shaped plate with the possibility to regulate branch spreading width as for the condylar size (Patent 33358 UA). Autografting was performed as for necessity. Results. Plate osteosynthesis was performed mainly through anterior approach with minimal tissues traumatization. Release of radial nerve we made as for necessity. This device provides the stable fixation even in a case of short distal fragment. Device for bone fragments fixation was placed on the posterior condylar surface and lower part of the humerus through olecranon osteotomy. Osteosynthesis with suggested device is one of the options with bone autografting and can be method of choice at repeated surgery. Follow-up period was 1–2 years and later. In 60 patients we obtained good results with completed bone union. Conclusions. Suggested device can be used in cases of distal humerus nonunion. It allows to decrease the damage of surgery, to avoid many complications. Key words. Complicated fractures of the distal humerus, devices for limited-contact multiplanar osteosynthesis.

The role of joint line position and restoration of posterior condylar offset in revision total knee arthroplasty : a systematic review of 422 revision knees arthroplasty

The aim of this systematic review was to evaluate the evidence on reservation of Posterior Femoral Condylar Offset (PFCO) and Joint Line (JL) after Revision Total Knee Arthroplasty (RTKA) for im- proved functional outcomes. A comprehensive search of PubMed, Medline, Cochrane, CINAHL, and Embase databases was conducted, with papers published from the inception of the database to October 2020 included. All relevant articles were retrieved, and their bibliographies were hand searched for further references on Posterior condylar offset and revision total knee arthroplasty. The search strategy yielded 28 articles. After duplicate titles were excluded, abstracts and full text were reviewed. Nine studies were assessed for eligibility, four studies were excluded because they did not fully comply with the inclusion criteria. Six articles were finally included in this systematic review. Based on this systematic review restoration of the JL and PFCO in RTKR is associated with a significant improvement in the post-operative range of motion, KSS, OKS, patellar function, and SF-36. Reservation of JL should be a major consideration when undertaking RTKA. Of note, increasing PFCO to balance the flexion gap while maintaining joint line should be well assessed intra-operatively. The upper limit of the PFCO that widely accepted is up to 40 % greater than that of the native knee. 4 mm is the upper limit for JL restoration. Level of evidence III.