Introduction. 47 yrs male patient had a prior history. 2005 Fx. proximal tibia (open Fx.). 2007 Metal removal. 2008 Arthroscopic debridement (2 times). He visited out hospital with severe pain and tenderness X-ray (Fig 1) and MRI (Fig 2) findings as follows. Conclusively, He had a chorinic osteomylitis of proximal tibia with soft tissue absess. 1st Surgery. I did arthroscopic debridement Arthroscopic finding shows synovitis, meniscus tear and chondromalacia. I did meticulous debridement (irrigation & curettage). 2nd Surgery. He did primary total knee arthro-plasty instead of two-stage exchange arthroplasty in may, 2010 at the another hospital. 3rd Surgery. After 7 months since he had did total knee arthroplasty, he visited to my hospital again with sudden onset of painful swelling & heating sensation. 4th Surgery. I did second stage reimplantation for infected total Knee arthroplasty after 7 weeks. Now he got a pain relief & ROM restroration. Results. Follow up 12 months X-ray showing all implants to be well-positioned and stable. Clinically, there was no implant considered to be loose. In this study, the knee society and functional scores at final follow up were 82 and 68. Conclusion. The infection after sequales of open proximal tibia fracture is treated by two-stage exchange total knee arthroplasty instead of primary total knee arthroplasty. Two-stage reimplantation of an infected total knee arthroplasty using a static antibiotic-cement spacer achieved an infection control and improvement in the clinical result 3). We use an antibiotic-loaded cement spacer(ALACS) preserved knee function between stages, resulting in effective treatment of infection, facilitation of reimplantation, and improved patient satisfaction 1). The principle surgical technique used for two-stage revision of infected total knee including: (1) exposure, (2) implant removal and debridement, and (3) construction of both static and mobile antibiotic spacers 2

Aim. In patients with bone sarcoma, placing mega prostheses in the proximal tibia is associated with high rates of infection. In studies with small numbers of patients and short follow-up periods, silver-coated mega prostheses have been reported to lead to reduced infection rates. To the best of our knowledge, this study is the largest one that has compared the infection rates with titanium versus silver-coated mega prostheses in patients treated for sarcomas in the proximal tibia. Method. The infection rate in 98 patients with sarcoma or giant cell tumour in the proximal tibia who underwent placement of a titanium (n = 42) or silver-coated (n = 56) mega prosthesis. *. was assessed, along with the treatments administered for any infection. Results. As the primary end point of the study, the rates of infection were 16.7% in the titanium group and 8.9% in the silver group, resulting in 5-year prosthesis survival rates of 90% in the silver group and 84% in the titanium group. Overall, seven of 56 patients in the silver group (12.5%) developed periprosthetic infection. Two patients became infected after revision surgery due to mechanical failure of the prosthesis. In the titanium group, one patient developed a periprosthetic infection after revision surgery (which was carried out in 50% of patients) due to a mechanical prosthetic failure, leading to an overall infection rate of 19.0% (eight of 42). Overall, nine of 12 (75%) periprosthetic infections in the two groups occurred within the first 2 years postoperatively, if later revision surgery due to mechanical failure was not necessary. Whereas three of the eight patients in the titanium group (37.5%) ultimately had to undergo amputation due to infected proximal tibia replacement, these mutilating surgical procedures were necessary in the silver group in only one patient (14.3%). In the titanium group, two-stage revision surgery with a temporary antibiotic-impregnated cement spacer was ultimately successful in four of eight patients (50.0%), but this procedure was necessary in only one patient in the silver group (14.3%). Conclusions. The use of silver-coated prostheses reduced the infection rate in a relatively large and homogeneous group of patients. In addition, less aggressive treatment of infection was possible in the group with silver-coated prostheses

Introduction. Precise implant matching with a resected bony surface is a crucial issue to ensure a successful total knee arthroplasty (TKA). Extremely undersized or oversized components should be avoided. Therefore, we should measure the exact anthropometric data of the resected bony surface preoperatively or intraoperatively. The purpose of this study was to intraoperatively analyze the exact anthropometric proximal tibial data of Japanese patients undergoing TKA and correlate these measurements to the dimensions of current prosthetic systems. Patients and Methods. Three hundred and seventy-three knees in 299 Japanese patients were included in this study. There were 246 women and 53 men with a mean age of 74 (range: 63–85) years. All TKAs were performed by 3 senior surgeons (TS, AK, and NM). The bone cut in the proximal tibia was made perpendicular to the longitudinal axis of the tibia in the frontal plane. Intraoperative measurements of the proximal tibial cut surface were taken after proximal tibial preparation. Akagi's line (center of the posterior cruciate ligament tibial insertion to the medial border of the patellar tendon attachment) was adopted as the anteroposterior axis line of the proximal tibia. A mediolateral (ML) line was drawn perpendicular to Akagi's line. Then, anteroposterior (AP), lateral anteroposterior (lAP), and medial anteroposterior (mAP) lines were drawn as shown in Figure 1. Results. There was a significant positive correlation between lAP and ML dimensions. Although there also was a significant positive correlation between lAP and mAP dimensions, individual knees presented much scatter (Figure 2). The lAP dimension was smaller than the mAP dimension in all knees by a mean of 4.5 ± 1.9 mm. The proximal tibia exhibited asymmetry between the lateral and medial plateaus. The recent data of 177 knees indicated that Akagi's line was located 1.0 ± 1.2 mm medial to the AP line. A comparison of the morphologic data and the dimensions of the implants, one of which was a symmetric tibial component (NexGen: Zimmer, Warsaw, Indiana), and the other asymmetric (Genesis II: Smith & Nephew, Memphis, Tennessee), indicated that an asymmetric tibial component could be beneficial in maximizing the coverage of the tibial plateau. However, the size variation of the asymmetric tibial component was poor and the lAP and mAP dimensions showed much scatter; thus, we should measure the proximal tibia and choose the proper tibial component during surgery. Conclusions. This study provides important reference data that may be useful for designing proper tibial components for Japanese patients

Osteoarthritic (OA) changes to the bone morphology of the proximal tibia may exhibit load transfer patterns during total knee arthroplasty not predicted in models based on normal tibias. Prior work highlighted increased bone density in transverse sections of OA knees in the proximal-most 10mm tibial cancellous bone. Little is known about coronal plane differences, which could help inform load transfer from the tibial plateau to the tibial metaphysis. Therefore, we compared the cancellous bone density in OA and cadaveric (non-OA) subjects along a common coronal plane. This study included nine OA patients (five women, average age 59.1 ± 9.4 years) and 18 cadaver subjects (four women, average age 39.5 ± 14.4 years). Patients (eight with medial OA and one with lateral OA) received pre-operative CT scans as standard-of-care for a unicompartmental knee replacement. Cadavers were scanned at our institution and had no history of OA which was confirmed by gross inspection during dissection. 3D reconstructions of each proximal tibia were made and an ellipse was drawn on the medial and lateral plateau using a previously published method. A coronal section (Figure 1) to standardize the cohort was created using the medial ellipse center, lateral ellipse center, and the tibial shaft center 71.5mm from the tibial spine. On this section, profile lines were drawn from the medial and lateral ellipse centers, with data collected from the first subchondral bone pixel to a length of 20mm. The Hounsfield Units (HU) along each profile line was recorded for each tibia; a representative graphical distribution is shown in Figure 2. The Area Under the Curve (AUC) was calculated for the medial and lateral sides, which loosely described the stiffness profile through the region of interest. To determine differences between the medial and lateral subchondral bone density, the ratio AUC[medial] / AUC[lateral] was compared between the OA and cadaver cohorts using a two-sample t-test. Data from the sole lateral OA patient was mirror-imaged to be included in the OA cohort. The majority of the OA patients appeared to have higher subchondral bone density on the affected side. Figure 3 compares the medial and laterals sides of each group using the AUC ratio method described above. For the cadaver group the AUC was 1.2 +/− 0.22, with a median of 1.1 [0.9 1.6], smaller than the mean AUC for the OA group, which was 1.4 +/− 0.39, with a median of 1.6 [0.93 2.1]. The p-value was 0.06. The increased density observed in OA patients is consistent with asymmetric loading towards the affected plateau, resulting in localized remodeling of cancellous bone from the epiphysis to metaphysis. From the coronal plane, bone was often observed in OA patients bridging the medial plateau to the metaphyseal cortex. Although the cadaver subjects were normal from history and gross inspection, some subjects exhibited early bone density changes consistent with OA. Future work looks to review more OA scans, extend the work to the distal femur, and convert the HU values to bone elastic moduli for use in finite element modelling

PURPOSE:. Unicompartmental knee arthroplasty (UKA) is becoming more commonly performed and is more technically challenging than total knee replacement. Retention of the anterior and posterior cruciate ligaments requires more accurate re-creation of the patient's normal anatomic posterior slope with UKA. Purpose of this study was to accurately determine the posterior tibial slope in patients having medial or lateral UKA performed. METHODS:. Retrospective review was performed of 2,395 CT scans performed for a customized UKA implant. Standard CT technique was used and the posterior slope was measured on the involved side of the proximal tibia. RESULTS:. CT measurements from 2031 knees undergoing medial UKAs had an average pre-operative posterior slope of 6.8 deg (SD 3.3), in these patients the posterior slope was between: 0–4 deg in 430 knees (21.2%), 4–7 deg in 696 knees (34.3%), 7–10 deg in 545 knees (26.8%), >10 deg in 360 knees (17.7%), and 13 knees (0.6%) had a reversed (anterior) tibial slope. Measurements from the 364 knees undergoing lateral UKAs showed an average pre-operative posterior slope of 8.0 deg (SD 3.3), in these patients the posterior slope was between: 0–4 deg in 43 knees (11.8%), 4–7 deg in 100 knees (27.5%), 7–10 deg in 118 knees (32.4%), >10 deg in 103 knees (28.3%), and 1 knee (0.3%) had a reversed (anterior) tibial slope. CONCLUSION:. There is marked variability in the posterior slope of the proximal tibial with 44.5% of medial plateaus and 60.7% of lateral plateaus having more than 7 deg of posterior slope pre-operatively. This is the first large CT based review of posterior slope variation of the proximal tibia. If attempting to match the patient's proximal slope during UKA, a routine setting of 5 degrees posterior slope will produce a posterior slope less than the patient's native anatomy in more than 50% of patients

Proximal tibial bone mineral density (BMD) has been shown to decrease following Total Knee Arthroplasty (TKA) by both dual-energy x-ray absorbtiometry (DEXA) and quantitative computed tomography (qCT)-assisted osteodensitometry. Little is known about changes in BMD following unicompartmental knee arthroplasty (UKA). Additionally, there are proposed differences in stress transmission between cemented metal and polyethylene (PE) components. We proposed two hypotheses. First, that proximal tibial BMD decreases following UKA. Second, that BMD loss would be greater below metal tibial components. We performed a prospective clinical trial of 50 consecutive UKAs in 49 patients performed by two surgeons at one institution. There were 25 mobile bearing Oxford and 25 fixed bearing Accuris arthroplasties, all were medial. BMD was assessed with qCT-assisted osteodensitometry scans prior to discharge and then at 1 and 2 years post surgery. Each CT slice was divided into medial and lateral halves and cortical and cancellous bone was analysed separately. The six 2mm slices immediately beneath the tibial implant were analysed using previously validated software to create a three-dimensional assessment of BMD. The lateral half was used as a control. There were a total of 30 females (60%), with an average age of 70 (49–84). One patient was lost to follow-up and another was unable to be analysed due to failure requiring revision before follow-up was complete. Preliminary results showed no significant change in BMD at either 1 or 2 years follow-up. There was no difference in BMD change between the mobile and fixed bearing prostheses, between the medial and lateral halves nor between cortical and cancellous bone. Final results will be presented at the AONZOA conference. This trial shows that UKA does not result in significant change to BMD at 2 years. The preservation of BMD may indicate that UKA is better at maintaining physiologic stress transfer than a TKA, which has been shown to be associated with a reduction in BMD

Introduction. We report a case which total knee arthroplasty (TKA) was able to be performed on schedule for the patient with occult fracture of proximal tibia which seemed to have occurred three months prior to the surgery, and has healed in short period of time by the use of Teriparatide. Case report. The patient is 84-year-old female, having right knee pain for past 7 years. Her knee pain increased by passive extension maneuver that was done by a bonesetter 3 months prior to the surgery. On her initial visit, the X-ray finding was severe medial osteoarthritis, and femorotibial angle (FTA) in the upright film was 197°, but there was no other disorder including fracture. Since the bone mineral density (BMD) of affected femoral neck was 62%YAM, and affected lateral femoral condyle as well as lateral tibial condyle seemed very porotic, we started using daily 20μg Teriparatide injection from 3 months prior to the surgery. Proximal tibial fracture was presented in the X-ray taken on the day before surgery, but since adequate bone union has already been formed, surgery was performed on schedule. Tibial implant with long stem was used for just to be certain. Thanks to the Teriparatide, the condition of cancellous bone in cut surface was excellent, and reaming of the tibia through fracture area felt very solid. Discussion. Proximal tibial fracture that occurred just before TKA is very rare. The fracture in this case was probably due to the maneuver done by the bonesetter. Teriparatide is indicated when osteoporosis is severe and the patient is at risk for fracture. We also indicate Teriparatide for the patients whose femoral neck BMD is very low and severe valgus knee or varus knee is present. Unloaded side of femoral or tibial condyle is usually very porotic in such a case. In our case, the fracture was so called fragility fracture which was found incidentally the day before surgery, but TKA could be done on schedule since adequate callus has been formed by the use of Teriparatide which started 3 months prior to the surgery

Introduction. Tibial components that match the resected proximal tibia may promote accurate rotational alignment and maximize coverage while minimizing overhang in total knee arthroplasty (TKA). Tibial component designs have traditionally been evaluated utilizing an overall anterior-posterior (AP)/medial-lateral (ML) ratio. However, since the tibial plateau is irregularly shaped, such a metric has drawbacks. Here, a detailed set of morphological metrics is used to evaluate six contemporary tibia designs against a multi-ethnic bone database. Methods. Tibial surfaces from 347 subjects, including 97 Indian (50m/47f), 99 Japanese (44m/55f), and 151 Caucasian (85m/66f), were virtually resected following a specific TKA procedure, as previous publications have shown surgical variability minimally impacts tibial resection morphology. Medial and lateral AP dimensions (MAP and LAP), ML width (ML), and medial and lateral anterior radii (MAR and LAR) were measured in a coordinate system constructed on the resected surface based on the neutral rotational axis (Fig. 1A). These metrics, along with anterior radius asymmetry (MAR/LAR), were regressed against ML for each ethnicity. The regressions were then compared with similar measurements obtained from tibial components in six contemporary TKA systems (one asymmetric: Design A; four symmetric: Designs B-E; and one anatomic: Design F). Results. The LAP of all six designs generally agrees well with the three ethnicities investigated. Designs A and F have MAP closer to tibial morphology (Fig. 2), while those of the symmetric designs are smaller than the morphological measurement, especially for tibiae with larger ML (Fig. 2). Across all three ethnicities, there is a positive correlation between anterior radii and ML (Fig. 3), which is reflected in each of the component designs. However, the symmetric designs tend to have bigger LAR and smaller MAR compared to the anatomic tibial morphology. Design F has the closest APs and anterior radii to the morphological measurements in all three ethnicities. The MAR/LAR is 1.8 ± 0.6 for Indian, 1.7 ± 0.4 for Caucasian, and 1.6 ± 0.3 for Japanese, and is negatively correlated with ML (Fig. 1B). However, except for Design F, which closely matches the measured morphology, all of the other designs investigated have constant and significantly lower MAR/LAR across all sizes (1 for the symmetric designs, 1.1 for the asymmetric design). Discussion. The ability to closely match the medial AP dimensions for Designs A and F suggests that anatomic or asymmetric designs with properly sized AP dimensions may reduce the amount of uncovered resected tibial surface compared to symmetric designs. Additionally, the current mismatch of the anterior radii in the asymmetric or symmetric component designs investigated may drive surgical compromise of coverage in order to facilitate rotational alignment or minimize overhang on the anterior regions of the resected tibia. Lastly, only the anatomic Design F accounts for the asymmetric characteristics of the tibial anterior radii, which may assist proper alignment of the tibial component, while the other five designs have either a radius ratio of 1 (Designs B-E) or a very small asymmetry (1.1, Design A). In summary, improved understanding of variations in tibial morphology across ethnicities can support continuous improvement of contemporary tibial component designs

Functional outcomes are important for patients with bone tumors undergoing lower extremity endoprosthetic reconstruction; however, there is limited empirical evidence evaluating function longitudinally. The objective of this study was to determine the changes in function over time in patients undergoing endoprosthetic reconstructions of the proximal femur, distal femur and proximal tibia. We conducted a secondary analysis of functional outcome data from the Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY) trial. Patient function was assessed with the Musculoskeletal Tumor Society Score 93 (MSTS) and the Toronto Extremity Salvage Score (TESS), which were administered preoperatively and at 3, 6 and 12 months postoperatively. Both instruments are scored from 0-100, with higher scores indicated greater function. Mean functional scores were evaluated over time and we explored for differences among patients undergoing proximal femur reconstructions (PFR), distal femur reconstructions (DFR) and proximal tibia reconstructions (PTR). The patient-importance of statistically significant differences in function was evaluated utilizing the minimally important difference (MID) of 12 for the MSTS and 11 for the TESS. We explored for differences in change scores between each time interval with paired t-tests. Differences based on endoprosthetic reconstruction undertaken were evaluated by analysis of variance and post-hoc comparisons using the Tukey test. A total of 573 patients were included. The overall mean MSTS and TESS scores were 77.1(SD±21) and 80.2(SD±20) respectively at 1-year post-surgery, demonstrating approximately a 20-point improvement from baseline for both instruments. When evaluating change scores over time by type of reconstruction, PFR patients experienced significant functional improvement during the 3-6 and 6-12 month follow-up intervals, DFR patients demonstrated significant improvements in function at each follow-up interval, and PTR patients reported a significant decrease in function from baseline to 3 months, and subsequent improvements during the 3-6 and 6-12 month intervals. On average, patients undergoing endoprosthetic reconstruction of the lower extremity experience important improvements in function from baseline within the first year. Patterns of functional recovery varied significantly based on type of reconstruction performed. The results of this study will inform both clinicians and patients about the expected rehabilitation course and functional outcomes following endoprosthetic reconstruction of the lower extremity

Aim. This study investigated if co-administration of rifampicin with moxifloxacin led to a decrease in moxifloxacin concentrations in relevant tissues in a porcine model of implant-associated osteomyelitis caused S. aureus. Pharmacokinetics were measured using microdialysis and treatment effect was measured by quantifying bacterial load from implant and periprosthetic bone following a 1-stage revision and antibiotics. Method. 15 female pigs received a stainless-steel implant in the right proximal tibia and were randomized into two groups. Infection was introduced by inoculating the implant with Staphylococcus aureus as previously described. 1. On day 7 post surgery, all pigs were revised with implant removal, debridement of implant cavity and insertion of a sterile implant. 7 days of treatment was then initiated with either moxifloxacin 400 mg iv q.d. (M) or moxifloxacin and rifampicin 450 mg iv b.i.d. (RM). At day 14, animals were sedated and microdialysis was applied for continuous sampling of moxifloxacin concentrations during 8 h in five compartments: the implant cavity, cancellous bone in both the infected and non-infected proximal tibia, and adjacent subcutaneous tissue on both the infected and non-infected side using a previously described setup. 2. Venous blood samples were collected. Implant and adjacent bone were removed for analysis. Results. Comparable cure rates (sterilization of both implant and bone) were observed with 5/8 pigs in the RM group compared to 3/7 in the M group, p= 0.62 (Fisher's exact test). Due to the small number of samples with growth, median log CFU/ml was 0 for implant and bones in both groups. AUC. 0-last. was significantly smaller in plasma for the RM group, 407; 315 – 499 min µg/mL vs 625; 536 – 724 min µg/mL (mean;95% CI), p= 0.002 (Student's t-test). For the implant cavity, there was a trend toward a lower AUC. 0-last. 425; 327 – 524 min µg/ml vs 297; 205 – 389 min µg/ml in the RM group compared to M, yet this difference was not statistically different, p = 0.06. For the other compartments for other parameters (C. max. and T. max. ) across all compartments, there was no difference. Conclusions. While the AUC. 0-last. was lower in plasma for animals treated with RM, both the concentrations at the site of infection and treatment outcomes were comparable between groups

Orthopaedic injuries in the knee are often associated with vascular injury. When these vascular injuries are missed devastating there are devastating outcomes like limb ablation. Pulse examination in these patients is not sensitive to exclude vascular injuries. That often lead to clinicians opting for Computed Tomography Angiogram (CTA) to exclude vascular. this usually leads to a burden in Radiology Department. This study aimed to evaluate the prevalence of vascular injury in patient with orthopaedic injury in the knee. The computed tomography (CT) done in patients with distal femur fracture, knee dislocation and proximal tibia fractures were retrieved from the picture archiving and comunication system (PACS). The CTs were done between June 2017 and June 2022. The computed tomography angiogram (CTA) reports were reviewed to determine cases that vascular injury. A sample size of 511 cases was collected. 386 cases were done CTA and 125 cases were not done CTA. There were 218 tibial plateau fractures, 79 knee dislocations, 72 distal metaphyseal femur fractures, 61 floating knees, 55 distal femure intraarticular and 26 proximal metaphyseal tibia fractures. The mechanisms of injury in these were gunshot, fall from standing height, fall from height, MVA, MBA, PVA and sports. Prevalance was 9.17% (47) of the total injuries in the knee. Prevalance in patients who were sent for CTA was 12.08%. Routine CTA in patients with injuries in the knee is not recomended. The use of ankle brachial index may decrease the number of CTA done

Aims. The aims of this retrospective study were to determine the incidence of extra-articular deformities (EADs), and determine their effect on postoperative alignment in knees undergoing mobile-bearing, medial unicompartmental knee arthroplasty (UKA). Patients and Methods. Limb mechanical alignment (hip-knee-ankle angle), coronal bowing of the femoral shaft and proximal tibia vara or medial proximal tibial angle (MPTA) were measured on standing, full-length hip-to-ankle radiographs of 162 patients who underwent 200 mobile-bearing, medial UKAs. Results. Incidence of EAD was 7.5% for coronal femoral bowing of >5°, 67% for proximal tibia vara of >3° (MPTA<87°) and 24.5% for proximal tibia vara of >6° (MPTA<84°). Mean postoperative HKA angle achieved in knees with femoral bowing ≤5° was significantly greater when compared to knees with femoral bowing >5° (p=0.04); in knees with proximal tibia vara ≤3° was significantly greater when compared to knees with proximal tibia vara >3° (p=0.0001) and when compared to knees with proximal tibia vara >6° (p=0.0001). Conclusion. Extra-articular deformities are frequently seen in patients undergoing mobile-bearing medial UKAs, especially in knees with varus deformity>10°. Presence of an EAD significantly affects postoperative mechanical limb alignment achieved when compared to limbs without EAD and may increase the risk of limbs being placed in varus>3° postoperatively. Clinical Relevance. Since the presence of an EAD, especially in knees with varus deformity>10°, may increase the risk of limbs being placed in varus>3° postoperatively and may affect long-term clinical and implant survival outcomes, UKR in such knees should be performed with caution

This study aimed to examine the effect of high tibial osteotomy (HTO) on the ankle and subtalar joints via analysis of static radiographic alignment. We hypothesised that surgical alteration of the alignment of the proximal tibia would result in compensatory distal changes. 35 patients recruited as part of the wider Biomechanics and Bioengineering Centre Versus Arthritis HTO study between 2011 and 2018 had pre- and postoperative full-length weightbearing radiographs taken of their lower limbs. In addition to standard alignment measures of the limb and knee (mechanical tibiofemoral angle, Mikulicz point, medial proximal tibial angle), additional measures were taken of the ankle/subtalar joints (lateral distal tibial angle, ground-talus angle, joint line convergence angle of the ankle) as well as a novel measure of stance width. Results were compared using a paired T-test and Pearson's correlation coefficient. Following HTO, there was a significant (5.4°) change in subtalar alignment. Ground-talus angle appeared related both to the level of malalignment preoperatively and the magnitude of the alignment change caused by the HTO surgery; suggesting subtalar positioning as a key adaptive mechanism. In addition to compensatory changes within the subtalar joints, the patients on average had a 31% wider stance following HTO. These two mechanisms do not appear to be correlated but the morphology of the tibial plafond may influence which compensatory mechanisms are employed by different subgroups of HTO patients. These findings are of vital importance in clinical practice both to anticipate potential changes to the ankle and subtalar joints following HTO but it could also open up wider indications for HTO in the treatment of ankle malalignment and osteoarthritis

During revision total knee arthroplasty (rTKA), proximal tibial bone loss is frequently encountered and can result in a less-stable bone-implant fixation. A 3D printed titanium alloy (Ti6Al4V) revision augment that conforms to the irregular shape of the proximal tibia was recently developed. The purpose of this study was to evaluate the fixation stability of rTKA with this augment in comparison to conventional cemented rTKA. Eleven pairs of thawed fresh-frozen cadaveric tibias (22 tibias) were potted in custom fixtures. Primary total knee arthroplasty (pTKA) surgery was performed on all tibias. Fixation stability testing was conducted using a three-stage eccentric loading protocol. Static eccentric (70% medial/ 30% lateral) loading of 2100 N was applied to the implants before and after subjecting them to 5×103 loading cycles of 700 N at 2 Hz using a joint motion simulator. Bone-implant micromotion was measured using a high-resolution optical system. The pTKA were removed. The proximal tibial bone defect was measured. One tibia from each pair was randomly allocated to the experimental group, and rTKA was performed with a titanium augment printed using selective laser melting. The contralateral side was assigned to the control group (revision with fully cemented stems). The three-stage eccentric loading protocol was used to test the revision TKAs. Independent t-tests were used to compare the micromotion between the two groups. After revision TKA, the mean micromotion was 23.1μm ± 26.2μm in the control group and 12.9μm ± 22.2μm in the experimental group. There was significantly less micromotion in the experimental group (p= 0.04). Prior to revision surgery, the control and experimental group had no significant difference in primary TKA micromotion (p= 0.19) and tibial bone loss (p= 0.37). This study suggests that early fixation stability of revision TKA with the novel 3D printed titanium augment is significantly better then the conventional fully cemented rTKA. The early press-fit fixation of the augment is likely sufficient for promoting bony ingrowth of the augment in vivo. Further studies are needed to investigate the long-term in-vivo fixation of the novel 3D printed augment

Introduction. Recent technological advancements have led to the introduction of robotic-assisted total knee arthroplasty to improve the accuracy and precision of bony resections and implant position. However, the in vivo accuracy is not widely reported. The primary objective of this study is to determine the accuracy and precision of a cut block positioning robotic arm. Method. Seventy-seven patients underwent total knee arthroplasty with various workflows and alignment targets by three arthroplasty-trained surgeons with previous experience using the ROSA® Knee System. Accuracy and precision were determined by measuring the difference between various workflow time points, including the final pre-operative plan, validated resection angle, and post-operative radiographs. The mean difference between the measurements determined accuracy, and the standard deviation represented precision. Results. The accuracy and precision for all angles comparing the final planned resection and validated resection angles was 0.90° ± 0.76°. The proportion within 3° ranged from 97.9% to 100%. The accuracy and precision for all angles comparing the final intra- operative plan and post-operative radiographs was 1.95 ± 1.48°. The proportion of patients within 3° was 93.2%, 95.3%, 96.6%, and 71.4% for the distal femur, proximal tibia, femoral flexion, and tibial slope angles when the final intra-operative plan was compared to post-operative radiographs. No patients had a postoperative complication requiring revision at the final follow-up. Conclusions. This study demonstrates that the ROSA Knee System has accurate and precise coronal plane resections with few outliers. However, the tibial slope demonstrated decreased accuracy and precision were measured on post-operative short-leg lateral radiographs with this platform

Primary malignant bone tumours are a scarce entity with limited population-based data from developing countries. The aim of the study is to investigate the frequency and anatomical distribution of primary malignant bone tumours in a local South African population. This will be an epidemiological retrospective study. Data will be used of patients that were diagnosed with primary malignant bone tumours over a period of nine years spanning from 1 January 2014 to 31 December 2022. This data will be received from private and government laboratories. Data to be considered are type of primary malignant bone tumours diagnosed, incidence of primary malignant bone tumours over a period of nine years and the most common anatomical sites of primary malignant bone tumours. The rationale behind our study is to assess the frequency of different primary malignant bone tumours in another geographic area of South Africa and to compare these findings to local and international literature. With a projected increase in diagnosis of primary malignant bone tumours in developing countries it is important to have more available data about primary malignant bone tumours from these areas to have a better understanding of these conditions and to understand the impact of the burden they impose on healthcare systems so that management of these conditions can also be improved. Preliminary results show that 23.83% of primary malignant bone tumours occurred in the age group 0–24 years of age, 49.22% in the 25–59 age group and 26.95% in the 60+ age group. The most common tumour that occurred was chondrosarcoma (49.21%) followed by osteosarcoma (41.80%) then Ewing's sarcoma (4,69%) and lastly chordoma (4.30%). From the 256 samples that met the inclusion criteria the five most common anatomical sites were distal femur (63), proximal tibia (41), proximal humerus (38), pelvis (34) and proximal femur (20)

Introduction. Coronal malalignment and leg length discrepancies (LLD) are frequently associated. Temporary hemiepiphysiodesis (tHED) is commonly employed for the correction of limb malalignment in skeletally immature patients. For treatment of LLD greater than 2 cm, lengthening with intramedullary legnthening nails is a safe and reliable technique. However, the combined application of these approaches in skeletally immature patients has not yet been investigated. Materials & Methods. Retrospective radiological and clinical analysis of 25 patients (14 females, 11 males) who underwent intramedullary femoral lengthening with an antegrade PRECICE® lengthening nail as well as tHED of the distal femur and / or proximal tibia between 2014 and 2019. tHED was conducted by implantation of flexible staples (FlexTack™) either prior (n = 11), simultaneously (n = 10), or subsequently (n = 4) to femoral lengthening. The mean follow-up period was 3.7 years (±1.4). Results. The median initial LLD was 39.0 mm (35.0–45.0). 21 patients (84%) presented valgus and 4 (16%) showed varus malalignment. Leg length equalization was achieved in 13 patients at skeletal maturity (62%). The median LLD of patients with a residual LLD > 10 mm was 15.5 mm (12.8–21.8). Limb realignment was obtained in nine of seventeen skeletally mature patients (53%) in the valgus group, and in one of four patients (25%) in the varus group. Conclusions. The combination of antegrade femoral lengthening and tHED can efficiently correct LLD and coronal limb malalignment in skeletally immature patients. Nevertheless, achieving limb length equalization and realignment may render difficult in cases of severe LLD and angular deformity. Furthermore, the reported techniques ought to be thoroughly planned and executed and require regular clinical and radiological examinations until skeletal maturity to avoid - or timely detect and manage - adverse events such as overcorrection and rebound of deformity

Background. Rotational alignment is important for the long-term success and good functional outcome of total knee arthroplasty (TKA). While the surgical transepicondylar axis (sTEA) is the generally accepted landmark on the distal femur, a precise and easily identifiable anatomical landmark on the tibia has yet to be established. Our aim was to compare five axes on the proximal tibia in normal and osteoarthritic (OA) knees to determine the best landmark for determining rotational alignment during TKA. Methods. One hundred twenty patients with OA knees and 30 without knee OA were recruited for the study. Computed tomography (CT) images were obtained and converted through multiplanar reconstruction so the angles between the sTEA and the axes of the proximal tibia could be measured. Five AP axes were chosen: the line connecting the center of the posterior cruciate ligament(PCL) and the medial border of the patellar tendon at the cutting level of the tibia (PCL-PT), the line from the PCL to the medial border of the tibial tuberosity (PCL-TT1), the line from the PCL to the border of the medial third of the tibia (PCL-TT2), the line from the PCL to the apex of the tibia (PCL-TT3), and the AP axis of the tibial prosthesis along with the anterior cortex of the proximal tibia (anterior tibial curved cortex, ATCC). Results. In OA knees, the mean angles were less than those in normal knees for all 5 axes tested. In normal knees, the angle of the ATCC axis had the smallest mean value (1.6° ± 2.8°) and the narrowest range. In OA knees, the angle of the PCL-TT1 axis had the smallest mean value (0.3° ± 5.5°); however, the standard deviation (SD) and range were wider than that of the angle of the ATCC axis. The mean angle of the ATCC axis was larger (0.8° ± 2.7°) than the angle of the PCL-TT1 axis, but the difference was not statistically significant (P =0.461). The angle of the ATCC axis had the smallest SD and the narrowest range. Conclusion. In OA knees, the AP axis of the proximal tibia showed greater internal rotation compared with normal knees. In our study, the ATCC was found to be the most reliable and useful anatomical landmark for tibial rotational alignment in TKA

Introduction. The conventional bone resection technique in TKA is recognized as less accurate than computer-assisted surgery (CAS) and patient-matched instrumentation (PMI). However, these systems are not available to all surgeons performing TKAs. Furthermore, it was recently reported that PMI accuracy is not always better than that of the conventional bone resection technique. As such, most surgeons use the conventional technique for distal femur and proximal tibia resection, and efforts to improve bone resection accuracy with conventional technique are necessary. Here, we examined intraoperative X-rays after bone resection of the distal femur and proximal tibia with conventional bone resection technique. If the cutting angle was not good and the difference from preoperative planning was over 3º, we considered re-cutting the bone to correct the angle. Methods. We investigated 117 knees in this study. The cutting angle of the distal femur was preoperatively determined by whole-length femoral X-ray. The conventional technique with an intramedullary guide system was used for distal femoral perpendicular resection to the mechanical axis. Proximal tibial cutting was performed perpendicular to the tibial shaft with an extramedullary guide system. The cutting angles of the distal femur and proximal tibia were estimated by intraoperative X-ray with the lower limb in extension position. When the cutting angle was over 3º different from the preoperatively planned angle, re-cutting of distal femur or proximal tibia was considered. Results. On the intraoperative X-ray, the average femoral cutting angle difference from preoperative planning was 0.1º (SD: 2.6º) and the average tibial cutting angle was 1.1º varus (SD: 1.8º). Over 3º and 5º outlier cases were observed in 15 knees and 5 knees on the femoral side and in 15 knees and 3 knees on the tibial side respectively. Cutting angle correction was performed in 18 knees on the distal femur and 17 knees on the proximal tibia. On the postoperative X-ray, over 3º and 5º outliers were observed in 16 knees and only 1 knee on the femoral side and in 11 knees and no cases on the tibial side respectively. Cases with outliers over 3º were not different between intra- and postoperative estimation; however, the number of over 5º outliers was decreased from 8 knees (6.8%) to 1 knee (0.9%) including both the femoral and tibial sides (p < 0.05, Chi-square test). Discussion. Precise bone cutting technique is important for TKA; however, the bone resection accuracy of the conventional technique is far from satisfactory. CAS, PMI, and portable navigation have been developed for precise bone resection in TKA. However, these new technologies involve additional cost and have not been clearly shown to improve accuracy. Most surgeons currently use the conventional technique, and we think it is possible to improve bone resection accuracy with the conventional technique in TKA. Our method is simple and requires just one intraoperative X-ray. This is cost-effective and can be performed by most surgeons. Our results indicate that a single intraoperative X-ray can reduce the number of excessive bone resection angle outliers in TKA

Introduction. Using the tibial extramedullary guide needs meticulous attention to accurately align the tray in total knee arthroplasty (TKA). We previously reported the risk for varus tray alignment if the anteroposterior (AP) axis of the ankle was used for the rotational direction of the guide. The purpose of our study was to determine whether aligning the rotational direction of the guide to the AP axis of the proximal tibia reduced the incidence of varus tray alignment when compared to aligning the rotational direction of the guide to the AP axis of the ankle. Materials and Methods. Clinical Study. A total of 80 osteoarthritis (OA) knees after posterior stabilized TKA were recruited in this study. From 2002 to 2004, the rotational alignment of the guide was adjusted to the AP axis of the ankle (Method A: Figure 1, N = 40 knees). After 2005, the rotational alignment of the guide was adjusted to the AP axis of the proximal tibia (Method B: Figure 1, N = 40 knees). The AP axis of the proximal tibia was defined as the line connecting the middle of the attachment of the PCL and the medial third border of the attachment of the patellar tendon. The guide was set at a level of 10 mm distal to the lateral articular surface. Postoperative alignment was compared between the two groups using full-lengthanteroposterior radiograph. Computer simulation. Computer simulation was performed to determine the effect of ankle rotation on tibial tray alignment, using three-dimensional bone and skin model reconstructed from CT images of 75 OA knees (Figure 2). The position of the distal end of the guide in Method B was evaluated on the coronal plane perpendicular to the AP axis of the proximal tibia and of the ankle respectively. <Displacement> was the distance from the distal end of the guide to the midpoint-malleolar points (+: medial position). <Distance ratio> was the ratio of <Displacement> dividing by the entire width of the malleolar. Results. The results of the postoperative alignment for both methods from the clinical study are shown in Table 1. The number of the knees with more than 3 degrees of varus aligned tibial component significantly decreased with the Method B from the Method A. The computer simulation showed that the position of the guide varied great among individuals in the direction of the AP axis of the ankle joint. Discussion. When an extramedullary alignment guide is used in TKA, a rotational mismatch between the proximal part of the tibia and the ankle joint can induce a varus alignment of the tibial component. Computer simulation also supported our conclusion that the surgeon should not evaluate the distal end of the guide in the direction of the ankle joint to minimize the effects of anatomic variation for proper coronal alignment