Dual plating of the medial and lateral distal femur has been proposed to reduce angular malunion and hardware failure secondary to delayed union or nonunion. This strategy improves the strength and alignment of the construct, but it may compromise the vascularity of the distal femur paradoxically impairing healing. This study investigates the effect of dual plating versus single plating on the perfusion of the distal femur. Ten matched pairs of fresh-frozen cadaveric lower extremities were assigned to either isolated lateral plating or dual plating of a single limb. The contralateral lower extremity was used as a matched control. A distal femoral locking plate was applied to the lateral side of ten legs using a standard sub-vastus approach. Five femurs had an additional 3.5mm reconstruction plate applied to the medial aspect of the distal femur using a medial sub-vastus approach. The superficial femoral artery and the profunda femoris were cannulated at the level of the femoral head. Gadolinium MRI contrast solution (3:1 gadolinium to saline ration) was injected through the arterial cannula. High resolution fat-suppressed 3D gradient echo sequences were completed both with and without gadolinium contrast. Intra-osseous contributions were quantified within a standardized region of interest (ROI) using customized IDL 6.4 software (Exelis, Boulder, CO). Perfusion of the distal femur was assessed in six different zones. The signal intensity on MRI was then quantified in the distal femur and comparison was made between the experimental plated limb and the contralateral, control limb. Following completion of the MRI protocol, the specimens were injected with latex medium and the extra-osseous vasculature was dissected. Quantitative MRI revealed that application of the lateral distal femoral locking plate reduced the perfusion of the distal femur by 21.7%. Within the dual plating group there was a reduction in perfusion by 24%. There was no significant difference in the perfusion between the isolated lateral plate and the dual plating groups. There were no regional differences in perfusion between the epiphyseal, metaphyseal or meta-diaphyseal regions. Specimen dissection in both plating groups revealed complete destruction of any periosteal vessels that ran underneath either the medial or lateral plates. Multiple small vessels enter the posterior condyles off both superior medial and lateral geniculate arteries and were preserved in all specimens. Furthermore, there was retrograde flow to the distal most aspect of the condyles medially and laterally via the inferior geniculate arteries. The medial vascular pedicle was proximal to the medial plate in all the dual plated specimens and was not disrupted by the medial sub-vastus approach in any specimens. Fixation of the distal femur via a lateral sub-vastus approach and application of a lateral locking plate results in a 21% reduction in perfusion to the distal femur. The addition of a medial 3.5mm reconstruction plate does not significantly compromise the vascularity of the distal femur. The majority of the vascular insult secondary to open reduction, internal fixation of the distal femur occurs with application of the lateral locking plate

Introduction. The use of vascularised fibula grafts is an accepted method for reconstructing the distal femur following resection of malignant childhood tumours. Limitations relate to the mismatch of the cross-sectional area of the transplanted fibula graft and thel ocal bone, instability of the construct and union difficulties. We present midterm results of a unique staged technique—an immediate defect reconstruction using a double-barrel vascularised fibula graft set in in A-frame configuration and a subsequent intramedullary femoral lengthening. Materials & Methods. We retrospectively included 10 patients (mean age 10 y)with an osteosarcoma of the distal femur, who were treated ac-cording to the above-mentioned surgical technique. All patients were evaluated with regards to consolidation of the transplanted grafts, hypertrophy at the graft-host junctions, leg length discrepancies, lengthening indices, complications as well as functional outcome. Results. The mean defect size after tumour resection was 14.5 cm, the mean length of the harvested fibula graft 22 cm, resulting in a mean (acute) shortening of 4.7 cm (in 8 patients). Consolidation was achieved in all cases, 4 patients required supplementary bone grafting. Hypertrophy at the graft-host junctions was observed in78% of the evaluable junctions. In total 11 intramedullary lengthening procedures in 9 patients had been performed at the last follow up. The mean Muskuloskeletal Society Rating Scale(MSTS) score of the evaluable 9 patients was 85% (57% to 100%)with good or excellent results in 7 patients. Conclusions. A-frame vascularised fibula reconstructions showed encouraging results with respect to defect reconstruction, length as well as function and should therefore be considered a valuable option for reconstruction of the distal femur after osteosarcoma resection. The surgical implementation is demanding though, which is emphasized by the considerable high number of com-plications requiring surgical intervention, even though most were not serious

Introduction. The human body is a complex and continually adapting organism. It is theorised that the morphology of the proximal femur is closely related to that of the distal femur. Patients that have abnormal anatomy in the proximal femur, such as a high femoral neck anteversion angle, may have abnormal anatomy in the distal femur to overcome proximal differences. This phenomenon is of key interest when performing Total Hip Replacement (THR) or Total Knee Replacement (TKR) surgery. The current design and placement of existing hip and knee implants does not account for any correlation between the anatomical parameters of the proximal and distal femur, where bone anatomy may have adapted to compromise for abnormalities. A preliminary study of 21 patients has been carried out to assess the relationship between the proximal and distal femur. The difficulties in defining and measuring key anatomical parameters on the femur have been widely discussed in the literature [1] due to its complex three dimensional geometry. Using CT scans of healthy octogenarians, it was possible to mark key anatomical landmarks which could be used to define various anatomical axes throughout the femur. Correlation analyses could then be carried out on these parameters to assess the relationship between proximal and distal femur morphology. Methods. Each femur was initially realigned along the mechanical axis (MA); defined by joining the centre of the femoral head (FHC) to the centre of the intercondylar notch (INC) [2]. All anatomical landmarks were then identified using the Materialise Mimics v12 software (Figure 1 and 2) and exported into Microsoft Excel for analysis. Key anatomical parameters which were derived from these landmarks included the femoral neck axis (FNA), femoral neck anteversion angle (FNAA) [1–4], condylar twist angle, clinical transepicondylar axis (TEA), trochlea sulcus angle and medial and lateral trochlea twist. A correlation analysis was carried out on SPSS Statistics v20 (IBM) to assess the relationship between proximal and distal anatomical parameters. Results. The correlation analysis displayed a positive linear correlation between the FNAA and the clinical TEA (adjusted R squared = 0.471, p < 0.001) indicating that an abnormally high FNAA is correlated with a higher TEA angle (Figure 3). No strong relationship was found between the FNAA and the additional distal parameters compared, in particular there was no trend between the FNAA and the geometry of the trochlea as measured by the sulcus angle and trochlea twist. Discussion. The morphology of the distal femur seems to be at least partially correlated with the proximal femur and the relationship should be studied further to assess any potential effect on THA and TKA surgery. An extension of this study should assess an increased patient sample size and further anatomical parameters

Analysis of the morphology of the distal femur, and by extension of the femoral components in total knee arthroplasty (TKA), has largely been related to the aspect ratio, which represents the width of the femur. Little is known about variations in trapezoidicity (i.e. whether the femur is more rectangular or more trapezoidal). This study aimed to quantify additional morphological characteristics of the distal femur and identify anatomical features associated with higher risks of over- or under-sizing of components in TKA. We analysed the shape of 114 arthritic knees at the time of primary TKA using the pre- operative CT scans. The aspect ratio and trapezoidicity ratio were quantified, and the post- operative prosthetic overhang was calculated. We compared the morphological characteristics with those of 12 TKA models. There was significant variation in both the aspect ratio and trapezoidicity ratio between individuals. Femoral trapezoidicity was mostly due to an inward curve of the medial cortex. Overhang was correlated with the aspect ratio (with a greater chance of overhang in narrow femurs), trapezoidicity ratio (with a greater chance in trapezoidal femurs), and the tibio- femoral angle (with a greater chance in valgus knees). This study shows that rectangular/trapezoidal variability of the distal femur cannot be ignored. Most of the femoral components which were tested appeared to be excessively rectangular when compared with the bony contours of the distal femur. These findings suggest that the design of TKA should be more concerned with matching the trapezoidal/ rectangular shape of the native femur

Osteomyelitis is an inflammatory condition accompanied by the destruction of bone and caused by an infecting microorganism. Open contaminated fractures can lead to the development of osteomyelitis of the fractured bone in 3-25% of cases, depending on fracture type, degree of soft-tissue injury, degree of microbial contamination, and whether systemic and/or local antimicrobial therapies have been administered. Untreated, infection will ultimately lead to non-union, chronic osteomyelitis, or amputation. We report a case series of 10 patients that presented with post-operative infected non-union of the distal femur with or without prior surgery. The cases were performed at Padmashree Dr. D. Y. Patil Hospital, Nerul, Navi Mumbai, India. All the patients’ consents were taken for the study which was carried out in accordance with the Helsinki Declaration. The methodology involved patients undergoing a two-stage procedure in case of no prior implant or a three-stage procedure in case of a previous implant. Firstly, debridement and implant removal were done. The second was a definitive procedure in form of knee arthrodesis with ring fixator and finally followed by limb lengthening surgery. Arthrodesis was planned in view of infection, non-union, severe arthritic, subluxated knee, stiff knee, non-salvage knee joint, and financial constraints. After all the patients demonstrated wound healing in 3 months along with good radiographic osteogenesis at the knee arthrodesis site, limb lengthening surgeries by tibial osteotomy were done to overcome the limb length discrepancy. Distraction was started and followed up for 5 months. All 10 patients showed results with sound knee arthrodesis and good osteogenesis at the osteotomy site followed by achieving the limb length just 1-inch short from the normal side to achieve ground clearance while walking. Our case series is unique and distinctive as it shows that when patients with infected nonunion of distal femur come with the stiff and non-salvage knee with severe arthritic changes and financial constraints, we should consider knee arthrodesis with Ilizarov ring fixator followed by limb lengthening surgery

Introduction: morphological analysis of the general shape of the bones and of their particular variations according to the patient age, gender and pathology is an important step to improve the orthopedic management. We aimed to performed a gender specific analysis of the bi and tridimensional anatomy of the distal femur in vitro and in vivo. Materials and Methods: in vitro data were obtained from CT-scan performed on 92 dry men femurs and 52 dry women femurs. Using a manual contouring method and a segmentation method, tridimensional reconstructions were obtained and according to two different algorithms, the regions of discrepancies between men and women were determined. An automatic calculation of 59 defined measurements was then performed. In vivo data providing from 59 CT-scans of men femur and 73 CT-scan of women femurs were acquired. Standardized bidimensional measurements at the level of the trochlear cut were performed. Results: in vivo, statistically significant differences were observed for the: medio-lateral distance (M-Ld women=7.4±0.4cm vs M-Ld men=8.4±0.5cm; p< 0.0001), anteroposterior distance (A-Pd women=5.9±0,4cm vs A-Pd men= 6.4±0.4cm; p< 0.0001) and for the ratio anterior-posterior distance/medio-lateral distance (p< 0.0001). The trochlear groove angle was comparable in the two groups. In vitro, the tridimensional shape of the distal femur was more trapezoidal in women than in men. Medio-lateral distances were also statistically greater in men than in women (p< 0.01), the ratio anterior-posterior distance/medio-lateral distance was also statistically greater in men than in women (p< 0.01) and the Q angle more open in women than in men (p< 0.01). Discussion: Three types of differences between men and women were observed in this gender specific evaluation of the distal femur anatomy. First, for a same anteroposterior distance, the medio-lateral distance was smaller in women. Second, the global shape of the distal femur was more trapezoidal in women and third the Q angle was more open in women. This gender specific anatomy should be clinically considered when performing total knee arthroplasty in women and gender specific implants may be required

Background. Most of contemporary total knee systems address on improving of range of motion and bearing materials. Although new total knee designs in most systems accommodated the knee morphology according to gender differences, reestablishing of the same anterior offset of the distal femur during total knee arthroplasty (TKA) has not been well addressed. Furthermore, in most total knee systems, the anterior offset of the femoral component is constant regardless of the increment of the femoral size. We hypothesized that change of the anterior offset of the distal femur during TKA might affect the quadriceps strength and immediate clinical outcomes which may result in improved design of the future femoral component. Purpose. To evaluate the peak quadriceps strength and immediate clinical outcomes related to the change of anterior offset of the distal femur during TKA. Materials & Methods. We prospectively evaluated 75 patients (75 knees) who had primary osteoarthritis and underwent an uncomplicated TKA. A measured-resection technique of surgery using a single design of semi-constrained posterior-stabilized prosthesis with patellar resurfacing was used in all knees. In every TKA, the patellar resection was quantified in order to provide a similar thickness of the patellar composite to the original patellar thickness. A uniform perioperative protocol was applied. The mean thickness from the medial and lateral sides of the resected anterior femur were evaluated and compared with the mean thickness of the anterior part of the femoral component. The peak quadriceps strength and peak hip flexor strength was evaluated before surgery, and then at 2 weeks, 6 weeks and 3 months, postoperatively, using a digital dynamometer. The Difference of thickness between the resected anterior femoral bone and the anterior femoral component was defined as the change of the anterior offset of the distal femur. Clinical outcomes, including Knee Society Scores (KSS) and Western Ontario and McMaster University Arthritis Index (WOMAC) scores at 2 weeks, 6 weeks and 12 weeks were evaluated in relation of muscle strengths. Results. Patients were divided in 2 groups according to the change of the anterior offset of the distal femur during TKA. Thirty knees (group A) had similar or increased anterior offset of the distal femur and 45 knees (group B) had decreased anterior offset of the distal femur. The mean thickness of the resected anterior femoral bones in group A and B were 4.8 mm and 9.7 mm, respectively. The mean changes of anterior offset in group A and B were (+)0.7 mm and (−)4.2 mm with statistical difference (p, 0.01). There were no differences in patient's demographic data including age, sex, and body mass index (BMI). Preoperatively, both groups had similar mean peak quadriceps strength (108.04 N vs.115.52 N, p, 0.191) and mean peak hip flexor strength (105.98 N vs.108.05 N, p.0.745). At 2-week follow-up (FU), group A had significantly better peak quadriceps strength (111.53 N vs. 99.75 N, p, 0.03) and improve of total WOMAC score (32.4 points vs. 27.4 points, p, 0.03) than those of group B, The improved WOMAC score was statistical significant in subgroup of function (16.7 points vs. 12.7, p, 0.04) However, the peak hip flexor strength, KSS clinical scores and function scores were not different. At 6-week FU 12-week FU, there were no differences in all measuring parameters. Discussion and Conclusion. Biomechanical study has shown that the anterior offset of the distal femur provides role as a lever arm for a proper quadriceps function. Therefore, with maintaining of the patellar thickness during TKA in individual patient, a constant thickness of the anterior offset of the femoral component regardless of size may result in change of the anterior offset of the distal femur and may affect the function of quadriceps. The present study demonstrated that, at 2 weeks postoperatively, patients who had increased anterior offset of the distal femur could significantly gain better peak quadriceps strength and improved WOMAC function score than those who did not. In addition, change of anterior offset of the distal femur had no relation with the peak hip flexor strength. A mean 4.2-mm decreasing of anterior offset of the distal femur during TKA caused a shorter lever arm to the quadriceps and resulted in reducing the peak quadriceps strength with no gross effect on hip flexor strength. Although peak quadriceps strength in patients who had increased anterior offset of distal femur correlated with improved WOMAC function score, this marginal statistical significance provided a very short time for advantages. As there was a similar or slightly increased of anterior femoral offset in Group A, the anterior overstuff should be very minimal. At 6 weeks and 12 weeks after surgery, we found that investigated parameters, as well as clinical outcomes, were not different in both groups. We concluded that the change of femoral offset during TKA provided a short effect on quadriceps strength and clinical outcomes for few weeks which had no clinical impact on the drive to improve the prosthetic design of the femoral component which has a constant thickness of the anterior offset

Purpose. The purpose of this study is to analyse regional differences in the microstructural and mechanical properties of the distal femur depending on osteoarthritic changes using micro-images based on finite element analysis. Materials and Methods. Distal femur specimens were obtained from ten donors composed of 10 women with OA (mean age of 65 years, ranging from 53 to 79). As controls, the normal distal femur was sampled from age and gender matched donors consisting of 10 women(mean age of 67 years, ranging from 58 to 81). The areas of interest were six regions of the condyles of the femur(Lateral-Anterior, Middle, Posterior; Medial=Anterior, Middle, Posterior). A total of 20 specimens were scanned using the micro-CT system. Micro-CT images were converted to micro-finite element model using the mesh technique, and micro-finite element analysis was then performed for assessment of the mechanical properties. Results. Trabecular bones from the distal femur in control and OA groups exhibited different microstructural and mechanical properties in the same region. BV/TV, Tb.N, Tb.S and Yield strength were different between LA and MMsignificantly (p=0.005). In control group, the lateral anterior region of the distal femur reflected subchondral trabecular remodeling, while in advanced OA group, the medial middle region showed prominent changes in the microstructural and mechanical properties. Conclusion. The authors concluded that with aging and the progress of primary OA, changes of patello-femoral reaction force induced subchondral trabecular changes of the anterolateral region initially, and then progressed to the medial middle and posterior region in advanced OA

Introduction. The evaluation of treatment modalities for distal femur periprosthetic fractures (DFPF) post-total knee arthroplasty (TKA) has predominantly focused on functional and radiological outcomes in existing literature. This study aimed to comprehensively compare the functional and radiological efficacy of locking plate (LP) and retrograde intramedullary nail (IMN) treatments, while incorporating mortality rates. Method. Twenty patients (15 female, 5 male) with a minimum 24-month follow-up period, experiencing Lewis-Rorabeck type-2 DFPF after TKA were included. These patients underwent either LP (n=10) or IMN (n=10). The average follow-up duration was 48 months (range: 24–192). Treatment outcomes, including functional scores, alignment, union time, complications, and mortality rates, were assessed and compared between LP and IMN groups. Clinical examination findings pre-treatment and at final follow-up, along with two-way plain radiographs, were utilized. Statistical analyses comprised Student's t-test and Kaplan-Meier survival analysis with a 95% confidence interval. Result. At final follow-up, the LP group demonstrated a mean Knee Society score of 67.2 ± 16.1, while the IMN group exhibited a score of 72.8 ± 9.4(P = 0.58). No statistically significant differences were observed in alignment between the groups[aLDFA (anatomical lateral distal femoral angle), P = 0.31; aPDFA (anatomical posterior distal femoral angle), P = 0.73]. The mean time to union was 3.7 ± 0.8 months for LP and 3.9 ± 0.6 months for IMN (P = 0.62). Complications such as infection occurred in 1 LP patient, and non-union was observed in 2 LP patients, while no complications were noted in IMN group(P < 0.01). Mortality rates were notably lower in the IMN group compared to the LP group across various time intervals. Conclusion. Both LP and IMN treatments yielded similar functional scores, alignment, and union time for DFPF post-TKA. However, the lower incidence of complications and mortality rates associated with IMN treatment suggest its superiority in managing DFPF following TKA

Purpose. Analysis of the morphology of the distal femur, and by extension of the femoral components in total knee arthroplasty (TKA), has been related to the aspect ratio, which represents the width of the femur. Little is known about variations in trapezoidicity (i.e whether the femur is more rectangular or more trapezoidal). This study aimed to quantify additional morphological characteristics of the distal femur and identify anatomical features associated with higher risks of over- or under-sizing of components in TKA. Method. We analyzed the shape of 114 arthritic knees at the time of primary TKA using the pre-operative CT scans. The maximum AP dimension was measured. The mediolateral dimensions were measured on the theoretical distal resection slice at three levels: the posterior region (MLP), the central region (MLC) and the anterior region (MLA) (Fig 1). The ‘aspect’ ratio (MLC/AP) ratio quantified how wide or narrow the shape is. The ‘trapezoidicity’ ratio (MLP/MLA) ratio quantified how rectangular or trapezoidal the shape is. We also quantified the medial and lateral ‘narrowing angles’ in the anterior and central zones (α and β) (Fig 2). The post-operative prosthetic overhang was calculated from CT-scan. We compared the morphological characteristics with those of twelve TKA models scanned using a three-dimensional optical scanning machine (ATOS II, GOM mbH, Braunschweig, Germany) and its photogrammetric analysis software (TRITOP, GOM mbH, Braunschweig, Germany). Results. There were significant variations in both the aspect ratio (1.16±0.07; range 0.98–1.31) and the trapezoidicity ratio (1.21±0.08; range 1.06– 1.46). Femoral trapezoidicity was mostly due to an inward curve of the medial cortex. The multivariate analysis indicated that prosthetic overhang was correlated to the ‘aspect ratio’ (more overhang in narrow femurs, p=0.002), to the ‘trapezoidicity ratio’ (more overhang in trapezoidal femurs, p=0.002), and to the Tibio Femoral Angle (more overhang in valgus knees, p=0.035). The geometries of the twelve specimen components can be compared directly with the morphological findings of this study. Some components had excessively low trapezoidicity ratios (i.e. were too rectangular) such as DePuy LCS and Stryker Scorpio. Other designs had trapezoidicity ratios closer to anatomic values such as Zimmer Nexgen, Zimmer Persona, DePuy Attune and Smith and Nephew Journey (Fig 3). Several components had excessively low anterior lateral narrowing angle (αL) such as DePuy LCS, Stryker Scorpio. All had insufficiently low medial narrowing angles. Conclusion. This study shows that rectangular/trapezoidal variability of the distal femur cannot be ignored. Most of the femoral components, which were tested appeared to be excessively rectangular when compared with the bony contours of the distal femur. These findings suggest that the design of TKA should be more concerned with matching the trapezoidal/rectangular shape of the native femur

Objective. In a cruciate retaining total knee arthroplasty (CR-TKA) for patients with flexion contracture, to ensure that an extension gap is of sufficient size to install an implant, the amount of distal femur bone resection needed is frequently larger in a patient with knee flexion contracture than in one without contracture. In this study, we compared the distal femur bone resection amount, the component-secured extension gap margin value, and the range of motion at 6 months after surgery between patients with knee flexion contracture and those without knee flexion contracture. Method. We examined 51 joints including 27 joints in patients with preoperative extension limitation of less than 5 degrees (the F0 group) and 24 joints in patients with limitation of 15 degrees or larger (up to 33 degrees; the FC group) who underwent CR-TKA with LCS RP (DePuy Synthes) between May 2013 and April 2014. In case with an extension gap 3 mm or smaller than the flexion gap after initial bone resection, we released posterior capsule adequately, trying to minimize the distal femur additional bone resection amount as possible. With installation of a femoral trial, the component gaps were measured using spacer blocks. The measured parameters included the intraoperative bone resection length, gap difference (FG − EG, i.e., difference between the flexion gap [FG] and extension gap [EG]), and range of motion 6 months after surgery. Results. No inter-group difference was found in the length of the distal femur bone initially resected in the medial side of distal femur(F0: 6.7 ± 1.3 mm, FC: 6.1 ± 1.4 mm) and total length of bone resection (= first + additional resection) in the lateral proximal tibia (F0: 10.3 ± 1.9 mm, FC: 10.4 ± 2.1 mm). The length of the additional distal femur bone resected was 0.9 ± 1.3 mm in the F0 and 1.5 ± 1.2 mm in the FC (P = 0.06; Mann-Whitney U). The FG-EG (F0: 0.7 ± 0.9 mm, FC: 0.6 ± 0.8 mm) showed no remarkable inter-group difference. The mean range of motion was changed from −2.3° to −0.6° at extension and from 130.4° to 128.7° at flexion in the F0 and from −19.8° to −2.7° at extension and from 113.7° to 122.3° at flexion in the FC. Conclusions. The amount of distal femur bone resected should not be simply increased because this may elevate the joint line, narrow the flexion range, and cause the joint instability in mid-flexion. The results of this study show that, in CR-TKA for patients with flexion contracture up to 30°, the length of distal femoral bone resection of approximately 1 mm larger than that in patients without contracture may ensure an extension gap of necessary and sufficient length to install an implant

Background:. Septic arthritis following intra-capsular penetration of the knee by external fixation devices is a complication of traction/fixation devices. This study aimed to demonstrate the capsular attachments and reflections of the distal femur to determine safe placements of wires. Methods:. The attachments of the capsule to the distal femur were measured in cadaveric knees. Medially and laterally measurements were expressed as percentages related to the maximal AP diameter of the distal femur. Results:. Mean distance of the anterior attachment was 79.5mm (Range 48.1–120.7mm). The medial capsular reflections were attached an average of 57% back from the anterior edge (Range 41–74%). Laterally the capsular reflections were attached an average of 48% from the anterior reference point (Range 33–57%). Discussion:. Capsular reflections varied. Medially the capsule attachment was up to 74% of diameter of distal femur at the level of the adductor tubercle. Therefore, the insertion of distal femoral traction pins or similar should be placed proximal to the adductor tubercle and no further than 25% of the distance to the anterior cortex. Care is needed to ensure pins do not travel to exit too anteriorly on the lateral side as capsular attachments were found to be up to a distance 48% of the diameter of the femur from anterior reference point

Study Aim. Femoral components used in total knee arthroplasty (TKA) are primarily designed on the basis of kinematics and ease of fixation. This study considers the stress-strain environment in the distal femur due to different implant internal geometry variations (based on current industry standards) using finite element (FE) analyses. Both two and three dimensional models are considered for a range of physiological loading scenarios – from full extension to deep flexion. Issues associated with micro-motion at the bone-implant interface are also considered. Materials and methods. Two (plane strain) and three dimensional finite element analyses were conducted to examine implant micro-motions and stability. The simple 2D models were used to examine the influence of anterior-posterior (AP) flange angle on implant stability. AP slopes of 3°, 7° and 11° were considered with contact between bone and implant interfaces being modeled using the standard coulomb friction model. The direction and region of loading was based on loading experienced at full extension, 90° flexion and 135° flexion. Three main model variations were created for the 3D analyses, the first model represented an intact distal femur, the second a primary implanted distal femur and the third a distal femur implanted with a posterior stabilising implant. Further each of the above 3D model sets were divided into two group, the first used a frictional interface between the bone and implant to characterise the behavior of uncemented implants post TKA and the second group assumed 100% osseointegration had already taken place and focused on examining the subsequent stress/strain environment in the femur with respect to different femoral component geometries relative the intact distal femur model. Results and Discussion. Analyses indicate a trend relating the slope of the anterior-posterior (AP) flange to implant loosening at high flexion angles for uncemented components. Once cemented, this becomes less important. Results from the 3D analyses show that the posterior stabilising implant causes stress concentrations which can lead to bicondylar fatigue fracture. All femoral components cause stress shielding in cancellous bone particularly when they are fully bonded. Investigations into implant micromotion show that revision implants with box sections provided more resistance to micromotion than the pegged primary implants. However for the gait cycle tested the maximum recorded micromotion of both implants was well within acceptable levels for osseointegration to occur

Introduction: Osteoarticular allograft represents a reliable option for distal femur reconstruction. The purpose of this study was to describe the technical details and results of distal femur tumor resection and reconstruction with an osteoarticular allograft. Material and Methods: One hundred and twenty-two patients who received an osteoarticular allograft after distal femur resection were reviewed, with a mean follow-up of 7 years. Key points for successful fixation are allograft selection, absolute stability and satisfactory soft-tissue reconstruction at the time of surgery that allows aggressive rehabilitation. Survival of the allograft was estimated with the Kaplan-Meier method. Functional and radiographic results were documented according to the Musculoskeletal Tumor Society scoring system at the time of the latest follow-up. Results: Three patients were lost to follow and twenty-three patients died for tumor related reasons without allograft failure. In the remaining 96 allografts, eighteen allografts failed due to 7 infections, 7 local recurrences, 1 massive resorption and 3 fractures. Overall allograft survival was 82% +/− 7.6% (+/− 2 SE) at five and ten years. Those patients who preserved the original allograft had an average functional score of 27 points and a mean radiographic score of 89%, which represents a good and excellent functional and radiographic result. Discussion and conclusion: Osteoarticular allograft is a successful procedure for reconstruction of the distal femur. Adequate preoperative planning, careful surgical technique and aggressive rehabilitation lead to excellent function and low complication rate

Introduction. Accurate alignment and sizing of the femoral component in total knee arthroplasty (TKA) is important for stability and functional outcomes. In relation to the shape of the distal femur, it has been reported that the medial-lateral (ML) femur width in women is narrower than that in men for the same antero-posterior (AP) length. In addition, it has been noted that the elevation of the anterior condyle in women is lower than that in men. Therefore, in TKA for women, it is suggested that a medial or lateral overhanging femoral component can cause pain or limit the range of motion (ROM). As a result, a gender-specific implant for women has been developed. However, there are few studies addressing the morphological dimensions of the distal shape of the femur in the Japanese population. The objective of this study was to reveal the appropriateness of using gender-specific implant for Japanese women. Methods. This study was based on 40 women (40 knees) and 40 men (40 knees) who had primary preoperative osteoarthritis of the knee. The average height was 161.2 cm for men and 149.4 cm for women. The average weight was 68.0 kg for men and 58.5 kg for women. These are significantly different. Resection of the distal femur for TKA was simulated with preoperative computed tomography (CT) data. The ML width on the anterior and distal cut surface, the ML width at the surgical epicondylar axis (SEA) level, the maximum AP length at the medial and lateral condyle, and the AP length after resection were measured. These values were compared between men and women, and compatibility with NexGen LPS-Flex and Gender Solution Femur (GSF) (Zimmer, Warsow, Ind) was evaluated. Results. On the anterior cut surface, the average ML width was 54.0 mm for men and 47.0 mm for women. There was a significant difference between them (P<0.01). The aspect ratio (AP/ML) at the SEA level and the resected distal surface was 0.74 and 0.65 for men and 0.76 and 0.70 for women, respectively. There were significant differences between them (P<0.01). Discussion and Conclusion. In general, the aspect ratio of the distal femur in the Japanese population was smaller than that in the Caucasian population. However, the femoral distal shape in women was narrower than that in men for the same AP length in the Japanese population. As the AP size increased, the femoral component in women tended to overhang the ML width. Therefore, the use of a gender-specific implant for women was suggested. In contrast, there were some cases in which the femoral component tended to be undersized compared with the ML width in men. [Fig. 1] For Japanese women, the use of a gender-specific component should be considered. Additionally, there is a need for further investigation of gender-specific components in men

Correct sizing of knee arthroplasty implants avoids problems such as stiffness from too large an implant, or periprosthetic fractures from undersizing. Currently most implants are based on a generic unisex population. Femoral component sizing is therefore based solely on the AP measurement after the distal femoral cut. In order to investigate the differences between the New Zealand population and other populations with reported anthropometrics we studied the anthropometrics of the male and female distal femur. The distal femur of 26 cadaveric knees was resected using standard cutting guides. Using a sizing guide the AP dimension was measured from the posterior condyle to the anterior cortex just proximal to the trochlea (posterior referencing). The ML dimension was measured at the cut surface in the coronal plane of the epicondylar axis. Overall AP measurement had a mean(standard deviation) of 62(±6.7) mm, the ML measurements had a mean (sd.) of 72(±6.6)mm yielding an ML/AP(100) ratio of 117(±11). The male AP mean was 67(±4.5) mm and female AP 57 (±4.4)mm. The male ML was 77 (±4.7)mm and female ML 68 (±4.5)mm. The ML/AP ratio for male was 111(±12) and female was 120 (±10). This pilot study has shown differences between genders in the NZ population even with this small sample size. As this data is important for designers of total knee implants, planning is currently underway to perform measurements intraoperatively from approximately 400 patients undergoing total knee replacement

Over 80% of patients are satisfied following total knee arthroplasty (TKA). Female gender was one of the factors found to be a predictor of poorer satisfaction. The landmarks commonly used to achieve correct rotation of the femoral component are the posterior condylar axis, the transepicondylar axes (TEA) & the anteroposterior axis (Whiteside’s line) of the distal femur. The design features of most conventional jig based TKA instrumentation assumes a constant relationship of 3 degrees external rotation between the posterior condylar axis & the epicondylar axis. However during TKA using computer assisted navigation, we observe that these rotational landmarks do not have a constant relationship & there is wide variation among the arthritic population & between the male & female rotational profile. We hypothesise no consistent relationship between the posterior condylar axis, the TEA & the anteroposterior axis of the distal femur. 125 Computerised Tomography (CT) scans of the knee were performed using a 3D helical CT scanner in subjects who did not have any pre-existing clinical & radiological evidence of knee arthritis. CT slices 3 mm in thickness were obtained over the distal femur from the level of the proximal pole of the patella. Standard protocols were established for identifying the bony landmarks & taking measurements. The posterior condylar axis, the TEA & the anteroposterior axis were constructed. The condylar twist angle (CTA), the posterior condy-lar angle (PCA) & the angles made by the TEA & the line perpendicular to the anteroposterior axis were then measured using the PACSWEB digital measurement tools. The data was analysed to determine the consistency of the angular relationship between the reference axes using the STATA data analysis & statistical software. Linear regression was used to investigate any differences in the angle measurements between genders. 125 CT scans of the knee were performed in 111 patients (60 males [65 knees] & 51 females [60 knees]). The mean age was 45 years (SD, 15 years). The results showed no significant difference between the rotational axes of the distal femur between men & women (CTA male(SD): female(SD): 5.9(1.6): 6.3(2.0) [p=0.317], PCA male(SD): female(SD): 2.3(1.5): 2.5(1.9) [p=0.648]). The results also showed it would be inappropriate to assume a constant relationship of 3 degress external rotation between the posterior condylar axis & the epicondylar axes (PCA mean (SD) 2.39(1.70) [p< 0.001], CTA mean (SD) 6.11(1.81) [p< 0.001]). Our study suggests no significant difference between the rotational reference axes of the distal femur between men & women. Furthermore, most jig-based systems result in 3 degress external rotation of the femoral component. Our results show this is not consistent & may be responsible for the pain in 20% of patients post TKA because of abnormal patellar tracking

The aim of the study was to evaluate the results of the LISS system for distal femur fractures. Eighteen consecutive patients with fractures of the distal femur treated with the LISS system were followed until fracture union. This group included intra-articular, extra-articular and periprosthetic fractures occurring from both high and low energy trauma. Fractures united in 17 out of 18 cases and only 1 patient required bone grafting. The patient with the fracture that didn’t unite had an early above knee amputation for major pressure areas and peripheral vascular disease. There were no infections but 2 cases of plate failure proximally. The LISS system is a good treatment option for fractures of the distal femur in both the osteoporotic patient and the patient with high energy trauma

Aim: To report the results of supracondylar nailing of periprosthetic fractures of the distal femur above total knee replacement. Methods: Six displaced peri-prosthetic fractures of the distal femur in six female patients were treated with titanium supracondylar nail (Depuy ACE) between October 1997 and November 1999. The mean age was 68 years (42–92). Four patients had history of rheumatoid arthritis and two had previously undergone bilateral total hip replacement. None of the patients was reported to have anterior notching of the distal femur. Six fractures were equally distributed between right and left side. Low velocity trauma was the cause of fracture in all patients. The knee implants were in place for an average period of 36 months (3 wk to 48 months). The average follow up was 20 months (6–36). Results: All fractures healed in an average period of 14.6 weeks (12–18). One patient suffered another fall and sustained a fracture of the shaft of the femur above the nail. This was treated with exchange nailing using a long supracondylar nail with good result. All fractures healed in a satisfactory alignment. There were no cases of infection, loss of reduction and implant failure. All patients achieved their pre-injury functional status. The average ROM at the knee was 86.6 degrees (70–100). At latest follow up, none of the prostheses showed any signs of loosening and two patients had undergone total knee replacement on the contralateral side. Conclusion: Supracondylar nailing is a satisfactory method of managing periprosthetic fractures of the distal femur above a well-þxed implant

Introduction A review of the the treatment of supracondylar fractures of the distal femur is presented. Methods The material presented consists of a review of published literature and personal experience. Results The introduction of the Condylar Blade Plate by the AO in the 1960s revolutionized the treatment of this injury. Numerous publications over the last 30 years attest to the superiority of the modern AO methods. The Comprehensive Classification of the supracondylar fractures greatly helps surgeons in decision making. The mid-line medial parapatelar surgical approach is preferred to the classical lateral incision. A lateral parapatellar incision has been in use recently in conjunction with the LISS and CLCP. A detailed understanding of the surgical anatomy of the distal femur prevents technical misadventures in securing stable fixation. Atraumatic reduction techniques have been developed to prevent devitalization of intermediate fragments which permits bridge plating and obviates the need of bone grafting multifragmentary fractures. Previously, failure to bone graft multifragmentary fractures was the commonest cause of failure of fixation. Current fixation devices are the classic condylar plate, the dynamic condylar screw, the condylar buttress plate, and the retrograde supracondylar femoral nail and the most recently developed LISS and the condylar locked compression plate. The choice of implant depends on the specific fracture pattern and associated soft tissue injury, concomitant apendicular and system injuries, the patient’s age and the presence of osteoporosis. The open supracondylar fracture presents unique problems which require careful judgement and staging in reconstruction. Even if they become infected, with proper stabilization 80% will still achieve satisfactory results. The supracondylar fracture in the presence of a total knee replacement is an absolute indication to surgical stabilization. It and osteoporosis present specific challenges which require specialized techniques of fixation for successful resolution. Polytrauma with multisystem injuries and certain specific concomitant articular injuries such as patellar fractures or fractures of the tibial plateau prejudice the outcome of treatment. Conclusions With modern surgical treatment, young patients with isolated Type A, Type B and C1 or C2 fractures can expect a normal knee as the outcome of treatment. Type C3 fractures and open fractures continue to be a challenge and their outcome depends on the degree of initial articular cartilage destruction, the degree of bone fragmentation and displacement, and on the degree of soft tissue damage. Articular cartilage injury and severe osteoporosis continue to be the two most important unsolved problems in fracture surgery