Posterior Lateral Condyle Research Articles

Femoral cartilage thickness measured on MRI varies amongindividuals: Time to deepen one of the principles of kinematic alignment in total knee arthroplasty. A systematic review.

Kinematically aligned total knee arthroplasty (KA TKA), as a pure resurfacing procedure, is based on matching implant thickness with bone cut and kerf thickness, plus cartilage wear. However, the assumption of a consistent 2 mm femoral cartilage thickness remains unproven. This study aimed to systematically review the available literature concerning magnetic resonance imaging (MRI) assessment of femoral cartilage thickness in non-arthritic patients. Our hypothesis was that cartilage thickness values would vary significantly amongindividuals, thereby challenging the established KA paradigm of 'one-cartilage-fits-all'. Systematic literature searches (Pubmed, Scopusand Cochrane Library) followed PRISMA guidelines. English-language studies assessing distal and posterior femoral cartilage thickness using MRI in non-arthritic adults were included. Studies lacking numerical cartilage thickness data, involving post-operative MRI, considering total femoro-tibial cartilage thickness, or failing to specify the compartment of the knee being studied were excluded. Overall, 27 studies comprising 8170 MRIs were analysed. Weighted mean femoral cartilage thicknesses were: 2.05 ± 0.62 mm (mean range 1.06-2.6) for the distal medial condyle, 1.95 ± 0.4 mm (mean range 1.15-2.5) for the distal lateral condyle, 2.44 ± 0.5 mm (mean range 1.37-2.6) for the posterior medial condyleand 2.27 ± 0.38 mm (mean range 1.48-2.5) for the posterior lateral condyle. Femoral cartilage thickness varies significantly across patients. In KA TKA, relying on a fixed thickness of 2 mm may jeopardize the accurate restoration of individual anatomy, leading to errors in implant coronal and rotational alignment. An intraoperative assessment of cartilage thickness may be advisable to express the KA philosophy at its full potential. Level IV.

Digital virtual reduction combined with individualized guide plate of lateral tibial condyle osteotomy for the treatment of tibial plateau fracture.

Current treatments do not support direct exposure of fracture fragments, resulting in the inability to directly observe the articular surface during surgery for accurate reduction and firm fixation. The aim of the study was to explore the treatment effect of digital virtual reduction combined with individualized guide plate of lateral tibial condyle osteotomy on tibial plateau fracture involving the lateral posterior condyle collapse. 41 patients with tibial plateau fracture involving the lateral posterior condyle collapse were recruited in the trial. All patients underwent Computed Tomography (CT) scanning before operation. After operation, fracture reduction was evaluated using Rasmussen score and function of knee joint was assessed using hospital for special surgery (HSS) score. 41 patients were followed-up 6-26 months (mean, 15.2 months). Fracture reduction was good after operation, with an average of 13.3 weeks of fracture healing without serious complications. The excellent and good rate was 97.6%. The joint movement degree was -5∘∼0∘∼135∘ with an average of 125.5∘. Digital virtual reduction combined with individualized guide plate of lateral tibial condyle osteotomy was effectively for treating tibial plateau fracture involving the lateral posterior condyle collapse.

Effect of Posterior Cruciate Ligament Resection on Gap Balancing in Robot-assisted Total Knee Arthroplasty.

Retention or sacrifice of the posterior cruciate ligament (PCL) is one of the most controversial issues while performing total knee arthroplasty (TKA). This study aimed to evaluate the impact of PCL resection on flexion-extension gaps, femoral component rotation, and bone resection amounts during robot-assisted TKA. This prospective study included 40 patients with knee osteoarthritis who underwent robot-assisted posterior-stabilized (PS) TKA between September 2021 and February 2022. Of the patients, 75% were women (30/40) with a mean age and BMI of 72.6 years and 27.4 kg/m2, respectively. The guidance module and camera stand assembly were used to capture gaps before and after PCL resection. Measurements of femoral component rotation and bone resection amounts were made in cruciate-retaining (CR) TKA mode and PS-TKA mode. After PCL resection, the mean change in the medial and lateral compartments of flexion gaps increased by 2.0 and 0.6 mm, respectively (p < 0.001). Compared with the CR-TKA mode group, the bone resection amounts of the medial posterior condyle and the lateral posterior condyle in the PS-TKA mode group decreased by 2.0 ± 1.1 and 1.1 ± 1.1 mm, respectively, and the external rotation of the femoral prosthesis relative to the posterior condylar axis and trans-epicondylar line was reduced by 1.0° ± 1.3° and 1.2° ± 1.6°, respectively (p < 0.001). The release of the PCL did not affect the extension gap, but significantly increased the flexion gap. Moreover, the increases in the medial flexion gap were greater than those of the lateral flexion gap. After PCL resection, less external rotation of the femoral prosthesis and fewer bone cuts of the posterior femur were needed in PS-TKA.

Outcomes of Anterior Lateral Approach and Gerdy's Tubercle Osteotomy for Tibial Plateau Fractures Involving the Posterior Lateral Condyle: A Retrospective Study of 20 Patients.

BACKGROUND The objective of this investigation was to assess the effectiveness of using T-shaped steel plates through the anterior lateral approach and Gerdy's tubercle osteotomy for treating posterior lateral tibial plateau fractures. MATERIAL AND METHODS A retrospective analysis was conducted on clinical data from 20 patients, aged on average 53.9±10.36 years, who were admitted for tibial plateau fractures involving the posterior lateral condyle between January 2019 and October 2022. The fixation and reduction of the posterior lateral bone block were performed using the anterior lateral approach combined with Gerdy's tubercle osteotomy to address the posterior lateral tibial plateau fracture. Post-surgery assessment was conducted using the Hospital for Special Surgery (HSS) knee combined score. RESULTS During the 12-24 (14.2±1.7) month postoperative period, we conducted 20 surgeries. Within 9 to 12 weeks, fracture healing transpired without any complications such as incision infection, nerve injury, or fracture displacement being detected. Assessment of knee joint function at the final follow-up was conducted using the HSS knee combined score, with results indicating 16 cases rated as excellent, 3 cases as good, and 1 case as fair. CONCLUSIONS In tibial plateau fractures impacting the posterior lateral condyle, the anterior lateral approach, combined with Gerdy's tubercle osteotomy, allows for direct exposure and manipulation of the posterior lateral bone block fracture. Using a T-shaped support plate and a lateral locking plate provides a reliable method for fracture fixation, aiding in convenient surgical positioning and intraoperative fluoroscopy. The treatment approach effectively manages fractures located on the posterior lateral aspect of the tibial plateau.

Surgical treatment of coronal shear fractures of the distal humerus with an intact lateral epicondyle by the lateral combined approach

BackgroundCoronal shear fractures of the distal humerus are not only rare and prone to misdiagnosis, but their surgical treatment can be challenging. We aimed to investigate the feasibility of exposing distal humeral coronal shear fractures with a combined lateral approach that preserves the extensors and lateral ulnar collateral ligament (LUCL) and to analyze the clinical efficacy of open reduction and internal fixation (ORIF) in the treatment of these injuries. MethodsWe included 45 patients who sustained coronal shear fractures of the distal humerus with the lateral epicondyle intact and were treated with ORIF from January 2013 to August 2020. The fractures were exposed by the lateral combined approach in which the tendons involving the common extensor, the extensor carpi ulnaris (ECU), and the LUCL were preserved. Two observation windows were formed anterior to and posterior to these tendons and the LUCL was used to achieve fracture reduction. Countersunk screws, with or without a plate placed on the posterior lateral condyle, were used to fix the fragments. The functional outcomes of these patients were reviewed and assessed with physical and radiographic examinations, range of motion (ROM) measurements, and self-evaluation Mayo Elbow Performance Index (MEPI) and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. ResultsIn total, 40 patients were followed up with for over 1 year and were included in the final analysis. The mean follow-up duration was 42±30 months (range, 12–107 months). The patients’ mean age was 42 years (range, 14–74 years). According to the Dubberley Classification, there were 15 type I, 17 type II, and 8 type III fractures. At the final follow-up, the mean flexion–extension arc was 131° (range, 65–150) and mean pronation and supination was 73° (range, 45–80) and 71° (range, 40–80), respectively. The mean MEPI score was 88 (range, 61–97) points; the results were excellent in 21, good in 13, fair in 4, and poor in 2 patients. The mean DASH score was 11 (range, 0–42) points. Neither functional score nor range of movement was associated with age, sex, fracture type, injury type, or surgical timing. ConclusionReduction and stable fixation with internal fixation for coronal shear fractures of the distal humerus can be achieved by the lateral combined approach. Early functional mobilization allows for satisfactory restoration of elbow function.

Asymmetric Implant Design for Posterolateral Overhang of the Femoral Component in Total Knee Arthroplasty: A Retrospective Computed Tomography-Based Study.

Introduction During total knee arthroplasty (TKA), also referred to as total knee replacement (TKR), patients may experience pain in the posterolateral knee. One possible cause is the impingement between the popliteus tendon and the femoral components. The purpose of this study was to analyze the posterolateral overhang of the femoral component using 3D template software. Methods Preoperative CT scan images of 50 knees (11 males and 39 females) with osteoarthritis of grade 2 or lower according to the Kellgren-Lawrence classification were analyzed. The mean age of the subjects was 73.8±7.6 years (range 52-84 years). The Athena (Soft Cube Co., Ltd., Osaka, Japan) knee 3D image-matching software was used for the analysis. The positions of the two femoral components (symmetrical and asymmetrical) were simulated. In the coronal plane, the component overhang was measured between the resected lateral part of the posterior femur and its corresponding component size, and the two designs were compared in three zones (proximal, central, and distal). Results In the simulated femoral component, the asymmetric design had a significantly lower component overhang than the symmetric design in the proximal zone of the lateral posterior condyle (0.2±1.9 mm vs. 3.5±1.6 mm, p<0.01). In the proximal zone, significant overhang (>3 mm) was observed in 30 knees (60.0%) with the symmetric design, but only three knees (6.0%) had asymmetric designs (p<0.01). Conclusions The posterolateral overhang of the lateral posterior condyle occurs when a symmetrical prosthesis is used. The use of an asymmetric implant with a small, rounded proximal portion of the lateral posterior condyle improves this overhang and is expected to decrease problems such as impingement of the popliteus tendon and improve patient satisfaction.

Paper 15: Is Asymmetry of the Medial and Lateral Posterior Femoral Condyles Associated with ACL Rupture: A Case Control Study of Pediatric Patients

Objectives: Rates of anterior cruciate ligament (ACL) injury in the pediatric population have increased in the last 20 years. While many risk factors have been investigated, to the authors knowledge no study has analyzed the difference in the posterior femoral condyles in patients who have sustained ACL rupture. Therefore, this case control study sought to understand the relationship between the medial and lateral posterior condyles, as well as examining distal femoral version. The authors hypothesized that pediatric patients who suffered ACL rupture will have a relatively larger medial posterior femoral condyle leading to increase structural valgus in flexion. Methods: Pediatric patients with a pre-operative knee MRI who underwent ACL reconstruction between February 2016 and June 2020 at a tertiary orthopedic hospital were collected. Cases were matched to controls based on sex, laterality of injury, and age at imaging within 1.5 years. Medial and lateral posterior condylar height was measured for each participant. Condylar difference was calculated as medial posterior condylar height minus lateral posterior condylar height. The distal femoral version was calculated as the angle between the femoral posterior cortical axis and the posterior condylar axis. Mann-Whitney U tests were used to compare continuous variables. Significance was set as a p≤0.05. Results: A total of 72 participants were included in this analysis - 36 cases and 36 controls. Median age was 13.5 ± 3.3 years for all participants. Condylar difference was noted to be 1.8 mm greater in cases than controls (p=0.038), while distal femoral version was noted to be 2.0° greater in cases than controls (p=0.025). Conclusions: This study demonstrated a significantly greater posterior condylar height difference and distal femoral version among pediatric patients who suffered ACL rupture compared to a matched control group. We speculate that this morphology leads to a relative increase in knee valgus in flexion. [Figure: see text][Table: see text][Figure: see text]

Independent of the preoperative coronal deformity, adjusted mechanical alignment leads in a high percentage to non-anatomical tibial and femoral bone cuts.

The technique of adjusted mechanical alignment (AMA) in total knee arthroplasty (TKA) has been described to achieve alignment and balancing goals in varus knees in a high percentage, albeit at the price of non-anatomical bone cuts. The purpose of this study was to analyze (1) whether AMA achieves similar alignment and balancing results in different types of deformity and (2) whether they can be achieved without altering the native anatomy. A series of 1000 patients with hip-knee-ankle (HKA) angles from 165° to 195° were analyzed. All patients were operated using AMA technique. According to the preoperative HKA angle, three groups of knee phenotypes (varus, straight, valgus) were defined. The bone cuts were analyzed for being anatomic (< 2mm deviation of individual joint surface) or non-anatomic (> 4mm deviation of individual joint surface). AMA reached the goals for postoperative HKA in over 93% in every group (varus: 636 cases, 94%, straight: 191 cases, 98%, valgus: 123 cases, 98%). In 0° extension, the gaps were balanced in varus knees in 654 cases (96%), in straight knees in 189 cases (97%) and in valgus knees in 117 cases (94%). A balanced flexion gap was found in a similar number of cases (varus: 657 cases, 97%, straight: 191 cases, 98%, valgus: 119 cases, 95%). In the varus group, non-anatomical cuts were performed at the medial tibia (89%) and the lateral posterior femur (59%). The straight group showed similar values and distribution for non-anatomical cuts (medial tibia: 73%; lateral posterior femur 58%). Valgus knees showed a different distribution of values, being non-anatomical at the lateral tibia (74%), distal lateral femur (67%) and posterior lateral femur (43%). In all knee phenotypes, the AMA goals were achieved in a high percentage by altering the patients' native anatomy. In varus knees, the alignment was corrected by non-anatomical cuts at the medial tibia, and in valgus knees at the lateral tibia and the lateral distal femur. All phenotypes showed non-anatomical resections on the posterior lateral condyle in approximately 50% of cases. III.

Retracted: 3D Printing Combined with Osteotomy of the Lateral Tibial Condyle for the Treatment of Tibial Plateau Fractures Involving the Lateral Posterior Condyle.

[This retracts the article DOI: 10.1155/2022/4245274.].

Posterior femoral condylar separation: Is it a particular type of osteochondritis dissecans in adolescents?

Introduction. Dissecting osteochondritis (RO) is based on damage to the subchondral bone, leading to its detachment and sequestration separately or together with articular cartilage with the possible formation of a free bone-cartilage fragment. The disease occurs more often in adolescents, accompanied by an increased risk of early arthrosis of the knee joint. Chronic traumatization of the subchondral bone leads to insufficient blood supply to a certain area of the growth zone of the secondary point of ossification of the femoral epiphysis, to ischemia and subsequent necrosis of the subchondral bone, which, according to modern literature, is the leading cause of the formation of the lesion. The typical localization of the RO focus is the lateral part of the medial condyle of the femur along the supporting surface. The present clinical analysis presents cases of atypical localization of dissecting osteochondritis with clinical features, specific signs on MRI, as well as various tactical approaches to treatment.Material and methods. This clinical review presents 3 cases of sequestration of the posterior lateral condyle of the femur in adolescents. Despite the similarity of the clinical picture and the MRI data, the features of the foci of RO were found in all children, which determined the need for an individual approach to therapeutic tactics. All children required surgical treatment, which was performed in the Department of Traumatology and Orthopedics of the N.F. Filatov DGKB in different volumes in each case: from transchondral osteoperforations and fixation of an osteochondral fragment with a screw to debridement of a fragmented focus with removal of osteochondral fragments.Results. All 3 clinical cases are united by atypical localization of the focus in the posterior lateral condyles of the femurs, the clinical course of the disease in the form of a low-intensity long-term pain syndrome, as well as the results of MRI of the knee joint. Most researchers adhere to the classical multifactorial etiological theory of dissecting osteochondritis, according to which the main mechanism of the origin of the lesion is mechanical overload of the subchondral bone with subsequent disruption of blood supply in it at the border with the secondary point of ossification of the femoral epiphysis. However, there is also data in the literature on congenital ossification disorder in the cartilaginous part of the growth zone of the secondary ossification point as the morphological basis of dissecting osteochondritis. The presented clinical cases cast doubt on the generally accepted model of primary damage to the subchondral bone as the only possible cause of the formation of the focus of RO, since patients have, among other things, signs of impaired ossification of the secondary ossification point of the femoral condyle, in one of whom a violation of ossification of the secondary ossification center was also determined in the patella in the form of patella bipartita.Conclusion. Inspite of all similarities connecting these cases there is still lack of data to judge about separate type of the OCD because every separate type of disease usually have particular morphological basis. There is a need of partial biopsy of these lesions to confirm or refute our hypothesis of posterior condylar separation being separate type of OCD. However these cases undoubtedly require particular managementwith special attention to timing of appropriate diagnostic procedures and surgical management to perform in time prior to osteochondral fragment separation. In case of the absence of any complaintswith particular MRI appearance of fragmented bone in the lesion with impaired ossificationindividual treatment planneeds to be defined.

Asymmetry of Posterior Condyles in Resection Plane and Axial Curvature for Total Knee Arthroplasty.

Understanding the morphology of the distal femur is essential for improving bone-implant match in total knee arthroplasty (TKA) and understanding the mechanisms behind knee kinematics. However, little is known about the asymmetry of the posterior condyles. Thus, this study aimed to thoroughly investigate asymmetries in sizes and shapes between the medial and lateral posterior condyles before and after femoral resections during TKA in osteoarthritic (OA) knees. Three-dimensional femoral models of 74 OA knees were constructed using computed tomography images. The morphologic measurements of the posterior condyle pre- and post-simulated osteotomy for TKA included the radii of the posterior condyles fitted to a circle on the sagittal and axial planes of the femoral coordinate system, the inclination angle of the articular surface and resected surface, and the width and height of the resected surface. Differences in the data were assessed using Student's t-test, and correlations were evaluated using the Pearson product-moment correlation. The radii of the medial posterior condyles fitted to the circle were, on average, 6 mm larger than those of the lateral condyles on the axial plane (p < 0.001) and 0.7 mm smaller than those of the lateral condyles on the sagittal plane (p=0.046). The inclination angles of the medial and lateral posterior condyles on the axial plane were significantly different with both pre-simulated and post-simulated osteotomy, respectively (both p < 0.001). The resected plane of the lateral posterior condyles displaced opposite inclination directions between the distal and proximal portions. Neither heights or widths of the medial posterior condyles were significantly different from those of their lateral counterparts (both p > 0.107). This study found asymmetrical inclination of the resected surface and coronal radii between the medial and lateral posterior condyles, which may relate to the posterolateral overhang of the lateral condyle after TKA and the progression of the knee OA. These findings provides valuable morphological information and may help improve the implant designs for TKA.

Preoperative Factors Predicting the Preservation of the Posterior Cruciate Ligament in Total Knee Arthroplasty.

ObjectivePredicting the successful preservation of posterior cruciate ligament (PCL) in total knee arthroplasty (TKA) is an important step for preoperative planning to secure the satisfactory outcomes. We aimed to examine the preoperative factors predicting the successful preservation of the PCL in cruciate‐retaining TKA and the outcome of sacrificing the PCL.MethodsIn this retrospective study, we analyzed TKAs consecutively performed by a single surgeon between January 2019 and August 2021 who had been preoperatively planned to undergo implantation of cruciate‐retaining (CR) prostheses. The outcome of the current study was whether the PCL was retained or sacrificed. Anterior‐stabilized (AS) tibial bearings when the PCL was sacrificed as needed were used intraoperatively. Age, sex, body mass index (BMI), and preoperative diagnosis from the patients' medical records were obtained. The medial‐lateral width of epicondyle (MLW), the medial posterior condyle height (MPCH), the lateral posterior condyle height (LPCH), the ratio of MLW and MPCH, the ratio of MLW and LPCH, the Insall–Salvati index, and the severity of the varus or valgus deformity were measured using preoperative radiographs. Univariate and multivariate regression were fitted to assess the association of these factors with the successful retention of PCL. To examine the influence of sacrifice of the PCL on the surgical procedure, the size of the tibial and femoral components, the thickness of the polyethylene insert, and the rate of patella replacement between the CR group and AS group were also compared using t tests or chi‐square tests.ResultsAmong 307 TKAs included, PCL was sacrificed with concurrent use of AS prostheses in 89 (29.0%) procedures. Knees with rheumatoid arthritis (P < 0.01), lower Insall–Salvati index (P < 0.01), and more severe varus deformity (P = 0.011) were at a higher risk of sacrificing the PCL intraoperatively. There was no significant difference in age, sex, BMI, MLW, MPCH, LPCH, ratio of MLW and MPCH, ratio of MLW and LPCH, size of the tibial and femoral components, or replacement of the patella between the CR and AS groups. Converting from CR to AS was associated with a higher risk of using a thicker polyethylene insert (P < 0.01).ConclusionRheumatoid arthritis, lower Insall–Salvati index, and more severe varus deformity were associated with an increased risk of sacrificing the PCL in TKAs planned to undergo implantation CR prostheses. Converting to AS tibial bearing may result in a thicker polyethylene insert. These factors should be carefully considered for the appropriate selection of prosthesis type preoperatively.

Intraoperative joint balancing procedure using an imageless robotic assisted technique does not necessarily result in kinematically aligned bicruciate stabilized total knee arthroplasty.

The primary aim of this study was to retrospectively evaluate the hip- knee- ankle. (HKA) angle and prosthetic alignment with three-dimensional computed tomography (3DCT) measurements in patients who underwent robotic-assisted (RA) TKA, with consideration of the soft tissue envelope via an intraoperative joint-balancing procedure. We hypothesized that intraoperative consideration of soft tissue laxity in individual patients using imageless RA technology will not necessarily result in kinematically aligned bicruciate stabilized total knee arthroplasty (KA TKA). This retrospective study included consecutive patients who underwent RA TKA between 2019 and 2020. The indication for TKA was varus osteoarthritis of the knee. During this period, 60 RA bi-cruciate stabilized TKAs were performed. Prosthetic alignments were measured using computer software with 3DCT. We determined prosthetic positioning and bone resection volume with consideration of the soft tissue envelope using an intraoperative full range of motion joint-balancing procedure during RA TKA. 3DCT scans of the entire lower extremity were taken before and after surgery. Postoperative varus HKA alignment occurred in 58% of patients who underwent RA TKA, 31% of knees were in femoral valgus alignment and tibial varus alignment, and 42% had femoral components in internal rotation among knees with femoral valgus alignment and tibial varus alignment. The mean thickness of the osteotomized medial and lateral posterior condyles of the femur were 11.2 and 9.1mm, respectively, based on 3DCT measurements. Intraoperative consideration of soft tissue laxity in individual patientsusing an imageless RA technique does not necessarily result in KA bicruciate TKA.

Navigated, gap-balanced, adjusted mechanical alignment achieves alignment and balancing goals in a very high percentage but with partially non-anatomical resections.

Navigated, gap-balanced adjusted mechanical alignment (AMA) including a 0° varus tibial cut and modification of angles and resections of the femoral cuts to obtain optimal balance accepting minor axis deviations. Objectives of this study were (1) to analyse to what extent AMA achieves the goals for leg alignment and gap balance, and (2) in what percentage non-anatomical cuts are needed to achieve these goals. Out of 1000 total knee arthroplasties (TKA) all varus knees (hip-knee-ankle (HKA) angle < 178°; n = 680) were included. All surgeries were performed as computer assisted surgery (CAS) in AMA technique. CAS data at the end of surgery were analysed with respect to HKA and gap-sizes. All bone cuts were quantified. Depending on the amount of deformity, a subgroup analysis was performed. It was analysed whether the amount of deformity influences the non-anatomical cuts by correlation analysis. AMA reached the goals for postoperative HKA (3° corridor) in 636 cases (93.5%). While extension and flexion gap balance were achieved in more than 653 cases (96%), flexion and extension gap size were equalled in 615 knees (90.4%). The resections of the lateral tibia plateau and distal and posterior medial femoral condyle were anatomical (Tibia: 7.0 ± 1.7mm; medial condyle distal: 7.8 ± 1.4mm; medial posterior: 8.2 ± 1.8mm). The number of non-anatomical resections for those cuts were low; 67 (9.9%); 24 (3.5%); 32 (4.7%). For the medial tibia plateau and the lateral posterior condyle, the cuts were non-anatomical in a high percentage of cases; Tibia: 606 (89.1%), lateral posterior condyle: 398 (58.5%). Moderate but significant correlations were found between resection differences and amount of deformity (medio-lateral: tibia: 0.399; distal femur: 0.310; posterior femur: 0.167). No correlations were found between resection differences and gap values. AMA reaches the intended target for HKA and gap balance in over 612 (90%) of cases and maintains the medial femoral condyle anatomically. Non-anatomical tibial resection causes increased external rotation of the femoral component and by that non-anatomical cut of the posterior lateral condyle. Nonanatomical resections of AMA might be one reason for the persisting high rate of unsatisfied patients after TKA. Anatomical and individual alignment philosophies might help to reduce this rate of dissatisfaction.

Adopting the Joint Line Theory for Bone Resection in Cruciate-Retaining Total Knee Arthroplasty to Prevent Flexion Gap Tightness.

BackgroundDuring a conventional measured resection using the posterior reference method for total knee arthroplasty (TKA) in varus knees, proximal tibia is resected from the lateral joint surface for the same thickness as the implant. Distal femur is resected from the worn medial surface for the same thickness as the implant. Posterior femur is resected using the posterior reference method with an external rotation for appropriate degrees. In this situation, although the joint line of the tibia is leveled to the height of lateral joint surface, the posterior joint line of the femur is leveled to the center of medial and lateral posterior condyle, which is a few millimeters lower than the lateral posterior condyle. This discrepancy between the proximal tibia‐posterior femoral joint line causes a tight flexion gap in cruciate‐retaining TKA. Therefore, downsizing of the femur is necessary to adjust the posterior joint line to the level of the lateral condyle.PerspectivesTo avoid this circumstance, the postoperative joint line should be leveled to the center of the original medial and lateral joint surface. Proximal tibia is resected from the lateral joint surface 1 mm to 2 mm thicker than the implant. Distal femur is resected from the worn medial surface 1 mm to 2 mm thinner than the implant. Posterior femur is resected using the posterior reference method with an external rotation for appropriate degrees. In this situation, all the joint lines are leveled to the center of the medial and lateral joint surface. Otherwise, use of an anatomically shaped implant with a physiologic joint line is another option to avoid joint line discrepancy.ConclusionsAdopting joint line theory for bone resection can prevent the flexion gap tightness that likely occurs in cruciate‐retaining TKA.

3D Printing Combined with Osteotomy of the Lateral Tibial Condyle for the Treatment of Tibial Plateau Fractures Involving the Lateral Posterior Condyle.

The treatment of the fracture of the tibial plateau outside the posterior condyle is always a difficult problem in the clinical work of orthopedic surgeons. In this study, we aim to investigate the clinical effect of 3D printing combined with osteotomy of the tibial lateral condyle in the treatment of tibial plateau fractures involving the external posterior condyle. From January 2012 to February 2020, the data of 94 patients with fracture of tibial plateau external posterior condyle treated by 3D printing combined with osteotomy were retrospectively analyzed, including 38 males and 56 females. The 94 patients were divided into 2 groups (freehand osteotomy group and guided osteotomy group), with 47 patients in each group. All patients received preoperative CT 3D scan, and 3D printing was performed according to the converted data to make a 1 : 1 solid size fracture model. Two groups of patients were treated with anterolateral combined with posteromedial incision intraoperatively, and osteotomy lines were designed according to preoperative 3D model. After surgery, the fracture reduction was evaluated according to the Rasmussen knee scoring standard, and the knee function was evaluated by the Hospital for Special Surgery (HSS) score. One year after operation, the Rasmussen score of the knee joint was 13-18 points, with an average of 15.73 points, among which 66 cases were excellent, 24 cases were good, and 4 cases were fair, with an excellent and good rate of 95.7% (45/47). The HSS score is as follows: 67-94 points, with an average of 82.67 points, among which 62 cases were excellent, 26 cases were good, 4 cases were fair, and 2 cases were poor (joint stiffness caused by refusal of postoperative rehabilitation exercise), with an excellent and good rate of 89.9% (44/47). The range of motion of knee joint was -5°~0°~135°, and the average range of motion was 125.5°. At the last follow-up, there were no serious complications such as common peroneal nerve injury, popliteal vascular injury, postoperative infection, and failure of internal fixation. 3D printing combined with osteotomy of the tibial lateral condyle is an effective method for the treatment of fractures of the tibial plateau external posterior condyle, and the postoperative treatment results are satisfactory. The customized osteotomy guide plate is used for more accurate osteotomy, less injury, and more accurate fixation with support screws.

Femur morfometrisi ve proksimal ile distal parçalar arasındaki korelasyon

Purpose: The harmony of the morphometric features of the proximal and distal parts of the femur is very important in terms of biomechanical function. The aim of the study is to examine the correlation between the proximal and distal parts of the femur and to produce regression formulas for implant design with morphometric properties in harmony.&#x0D; Materials and Methods: The study was carried out on 33 dry femurs in the bone collection of Harran University Faculty of Medicine, Department of Anatomy. Four parameters related to femur length and segments, sixteen parameters related to proximal femur and sixteen parameters related to distal femur were measured. Statistically, descriptive statistics, correlation and linear regression analyzes were made.&#x0D; Results: Entire femur length was 400.27 ± 39.15 mm, diameter of femur neck was 32.82 ± 3.37 mm, inclination angle was 134.11 ± 6.25, declination angle was 17.28 ± 7.53, transcondylar axis length was 78.37 ± 5.49 mm, medial posterior condyle width was 27.83 ± 2.37 mm, lateral posterior condyle width was 26.77 ± 1.54 mm, intercondylar notch width was 18.61 ± 2.67 mm, and intercondylar notch depth was 23.23 ± 5.22 mm found. &#x0D; Conclusion: We believe that the data we have obtained will benefit orthopedists and implant manufacturers on the issue of that the parts of the femur should be in harmony for biomechanical function and this compatibility should be taken into account when designing the implant, and also forensic scientists and anthropologists in identification.

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

BackgroundThere 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.MethodsNinety-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.ResultsThe 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.ConclusionsThe 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.

Possible role of MRI-detected osteophytes as a predictive biomarker for development of osteoarthritis of the knee: A study using data from the Osteoarthritis Initiative

ObjectiveTo elucidate the possible role of MRI-detected osteophytes as a predictive imaging biomarker for knee osteoarthritis (KOA). DesignSubjects (n ​= ​303) were selected according to the following inclusion criteria from the Osteoarthritis Initiative (OAI) data set: (1) ​< ​55 years old; (2) Western Ontario and McMaster Universities Arthritis Index pain score of 0; (3) Kellgren-Lawrence (KL) system grade 0 or 1; and (4) Complete MRI data set of the right knee. A pre-OA group (POA) consisted of subjects who developed KL grade 2 or more within 96 months, and a non-OA group (NOA) that remained KL 0 or 1 during that period. Baseline MRIs were assessed for osteophyte formation. Twenty-five locations were examined according to the MOAKS osteophyte score. Osteophytes at each location were assessed in terms of their predictive value for OA development. ResultsThirty-two subjects were POA and 271 were NOA. Age, BMI, and sex did not differ between the two groups. In the POA group, the number of subjects with osteophytes tended to be higher at all 25 sites. Forward stepwise regression analysis revealed five locations - medial patella, lateral intra-condylar notch of the femur, lateral femoral condyle, tibial spine, and lateral posterior condyle - were important for the prediction of KOA development. Having more than two osteophytes at these five locations predicted KOA development with a sensitivity of 0.75 and specificity of 0.79. ConclusionsMRI-detected osteophytes could serve as a predictive biomarker of KOA development within 96 months after detection.

Verification and clinical translation of a newly designed "Skywalker" robot for total knee arthroplasty: A prospective clinical study.

ObjectiveTo evaluate accuracy of an innovative “Skywalker” system, a newly designed, robot-assisted operation system for orthopaedics via a clinical trial at knee joint.MethodsWe conducted a prospective analysis of the clinical data of 31 patients who underwent total knee arthroplasty assisted by the “Skywalker” robot (Microport, Suzhou, China) from June 2020 to January 2021. Five male patients and 26 female patients aged 69.68 ​± ​6.11 years (range: 57–79 years) were diagnosed with knee osteoarthritis and indicated for surgery. The “Skywalker” surgical robotic system was adopted to make a preoperative plan for knee arthroplasty. When the robotic arm reached the specified position during the operation, a single surgeon performed the osteotomy with a cutting saw through the cutting jig, and the difference between the actual and the expected resection thickness, and the preoperative and postoperative lower limb alignments were measured.ResultsThe actual error of the resection thickness was the difference between the actual and the expected resection thickness. The absolute error of the resection thickness was the absolute value of the actual error of resection thickness. The absolute errors of the resection thickness of the medial and lateral condyle of the distal femur, the medial and lateral posterior condyle of the femur, and the medial and lateral sides of the tibial plateau were 0.87 ​± ​0.63 ​mm, 1.02 ​± ​0.67 ​mm, 0.74 ​± ​0.46 ​mm, 0.98 ​± ​0.81 ​mm, 0.92 ​± ​0.66 ​mm, and 1.04 ​± ​0.84 ​mm, respectively. The absolute angle errors between the actual postoperative angles and the preoperative planned angles of the lower limb alignment angles, coronal femoral component angles, and coronal tibial component angles were 1.46° ​± ​0.95°, 1.13° ​± ​1.01°, and 1.05° ​± ​0.73°, respectively. Besides, 100% of the absolute error of the HKA angles was within 3°. In addition, compared to the preoperative lower limb alignment angle, 90.32% of the postoperative lower limb alignment angles of 31 patients were closer to 180° after the operation. All 31 patients underwent a successful surgery, and no relevant complications occurred after the operation, such as surgical site infection, deep venous thrombosis, or vascular and nerve injury.ConclusionThe “Skywalker” system has good osteotomy accuracy, can achieve the planned angles well, and is expected to assist surgeons in performing accurate bone cuts and reconstructing planned lower limb alignments in the relevant clinical applications in future.