Introduction. Total knee arthroplasty (TKA) is a well-established procedure associated with excellent clinical results. We have previously reported that intraoperative knee kinematics correlate with the clinical outcome in mobile bearing TKA. In addition, the intraoperative knee kinematics pattern does not correlate with the degree of preoperative knee deformity in mobile bearing TKA. However, the relationship among preoperative knee deformity, intraoperative kinematics and clinical outcome in fixed bearing TKA has been unknown. The purpose of this study is to compare the relationship among preoperative knee deformity, knee kinematics after fixed bearing TKA and the clinical outcome including the subjective outcomes evaluated by the new knee society score (KSS). Materials and Methods. A cross-sectional survey of thirty-five consecutive medial osteoarthritis patients who had a primary TKA using a CT-based navigation system was conducted. All knees had a Kellgren-Lawrence grade of 4 in the medial compartment and underwent a primary posterior stabilized TKA (Genesis II, Smith&Nephew) between May 2010 and October 2012. In all cases, a computed tomography-guided navigation system (Brain LAB, Heimstetten, Germany) was used. All surgery was performed by the subvastus approach and modified gap technique. Intraoperative knee kinematics was measured using the navigation system after implantation and closure of the retinaculum and soft tissue except for the skin. Subjects were divided into two groups based on intraoperative kinematic patterns: a medial pivot group (M group, n=19)(Figure 1) and a non-medial pivot group (N group, n=16)(Figure 2). Subjective outcomes with the new KSS and clinical outcomes were evaluated. Statistical analysis to compare the two groups was made using unpaired a Student t test. Result. Regarding the postoperative clinical result (knee flexion angle, knee extension angle, mechanical FTA,% mechanical axis), there were no significant differences between the two groups. Although there were also no significant differences in KSS evaluation between the two groups, there was a tendency for M group to be superior to N group in current knee symptom (M group: 17.3±5.6, N group: 12.9±8.2, p = 0.07) and functional activities (M group: 55.1±21.5, N group: 42.7±22.6, p = 0.10). Regarding preoperative examination, varus knee deformity (mechanical FTA and% mechanical axis) in N group was significantly more severe than that of M group (p=0.04, p=0.04, respectively). Discussion. Over half of patients (54%) could achieve medial pivot kinematics in fixed bearing TKA with the possibility to improve a subjective clinical result. Although we previously could not detect any relationship between preoperative varus knee deformity and intraoperative kinematics in mobile bearing TKA, the preoperative varus knee deformity in the non-medial pivot group was significantly severer than that of the medial pivot group in fixed type TKA. Our results indicate that if a TKA is done to a severe varus knee deformity the postoperative knee kinematics tend to result in a non-medial pivot pattern. In conclusion, because it tends to result in a non-medial pivot pattern, extra care needs to be taken to avoid postoperative abnormal knee kinematics in the performance of a fixed type TKA to a severe varus knee deformity

Introduction. To evaluate the results of correction of knee deformities based on deformity analysis in Achondroplasia, the commonest skeletal dysplasia as some have concomitant ligamentous deformities. Materials and Methods. Retrospective study from a prospective database (2007–2020) of achondroplasts who underwent growth modulation. Analysis of medical records with objective measurement of mechanical axis radiographs was done (Traumacad). Satisfactory alignment was defined as neutral to slightly varus (0–15 mm MAD) so that the MCL/LCL laxity is not revealed. Results. 23 patients, 41 limbs, 34 bilateral, 6 unilateral underwent multiple growth modulation procedures. 2 had valgus knees. 15 patients underwent proximal fibular epiphysiodesis in addition for LCL laxity with one isolated fibular epiphysiodesis. Mechanical axis deviation (MAD) improved or normalised in 16 patients (70%). 4 patients were still undergoing correction. 4 patients needed further surgery out of which 2 patients were over 13 years when growth modulation was attempted and 2 needed correction of ankle varus. JLCA improved/ normalised in 12 patients (75%) with evidence of indirect LCL tightening and no improvement was seen in 4. The rate of correction was MAD 0.61mm/month, LDFA 0.29°/month and MPTA 0.13°/month; expectedly lower in achondroplasia due to lower growth velocity. Conclusions. This study highlights the pathology, application of growth modulation as per deformity analysis unlike previous studies. Proximal fibular epiphysiodesis improves LCL laxity in a majority of these children and is a simple procedure compared to our published series with indirect LCL tightening with frames

This study was performed at Assiut University, Assiut, Egypt. Anterior distal femoral hemiepiphysiodesis (ADFH) using intra-articular plates for the correction of paediatric fixed knee flexion deformities (FKFD) has two main documented complications: postoperative knee pain and implant loosening. This study describes a biomechanical analysis and a preliminary report of a novel extra-articular technique for ADFH. Sixteen femoral sawbones were osteotomized at the level of the distal femoral physis and fixed by rail frames to allow linear distraction simulating longitudinal growth. Each sawbone was tested twice: first using the conventional technique with medial and lateral parapatellar eight plates (group A) and then with the plates inserted in the proposed novel location at the most anterior part of the medial and lateral surfaces of the femoral condyles with screws in the coronal plane (group B). Gradual distraction was performed, and the resulting angular correction was measured. Strain gauges were attached to the plates, and the amount of strain (and equivalent stress) over the plates was recorded. This technique was then applied to 9 paediatric FKFDs of different aetiologies. The preoperative FKFD and the amount of subsequent angular correction were measured. The amount of angular correction was higher in group B at 5, 10-, and 15-mm of distraction (p<0.001). The maximum and overall stresses measured throughout the distraction process were higher in group A (p<0.001). The mean FKFD improved from 24 ± 9° preoperatively to 9 ± 7° after 10 ± 3° months (p<0.001). The correction rate was 1.81 ± 0.65° per month. During ADFH, the fixation of the eight plates in the coronal plane at the anterior part of the femoral condyles may produce greater correction and lower stresses over the implants as compared to the conventional technique. Preliminary results from our initial series seem to support the effectiveness of this technique with respect to the degree of angular correction achieved

Introduction. The constitutional knee anatomy in the coronal plane includes the distal femoral joint line obliquity (DFJLO) which in most patients is in slight valgus positioning. Despite this native anatomy, the mechanical positioning of the femoral component during primary total knee arthroplasty (TKA) often ignores the native DFJLO opting to place the femur in a set degree of valgus that varies upon the practitioner's practice and experience. Unfortunately, this technique is likely to generate high rate of distal lateral femoral overstuffing. This anatomical mismatch might be a cause of anterior knee pain and therefore partly explain the adverse functional outcomes of mechanically aligned (MA) TKA. Our study aims at assessing the relationship between constitutional knee anatomy and clinical outcomes of MA TKA. We hypothesized that a negative relationship would be found between the constitutional frontal knee deformity, the distal femoral joint line obliquity, and functional outcomes of MA TKA with a special emphasize on patellofemoral (PF) specific outcomes. Methods. One hundred and thirteen patients underwent MA TKA (posterior-stabilized design) for primary end-stage knee osteoarthritis. They were prospectively followed for one year using the New KSS 2011 and HSS Patella score. Residual anterior knee pain was also assessed. Knee phenotypes using anatomical parameters (such as HKA, HKS, DFJLO and LDFA (Lateral distal femoral angle)) were measured from preoperative and postoperative lower-limb EOS® images (Biospace, Paris, France). We assessed the relationship between the knee anatomical parameters and the functional outcome scores at 1 year postoperatively. Results. We investigated four groups according to the preoperative obliquity of the distal femur and HKA. The group with high DFJLO and varus knee deformity demonstrated lower HSS scores (drop>10%, p=0.03) and higher rate of anterior knee pain (p=0.03). Higher postoperative variation of LDFA was associated with lower HSS scores (r = −0.2367, p=0.03) and with higher preoperative DFJLO (p=0.0001) due to the MA technique. Knee phenotypes with LDFA<87° presented higher risk of variation of LDFA. No correlation was found using New KSS 2011 outcomes at one-year follow-up. Discussion/Conclusion. Disregard of the constitutional knee anatomy (LDFA and DFJLO) when performing a MA TKA may generate a non-physiologic knee kinematics that impact patellofemoral outcomes and resulting in residual anterior knee pain. While these results are restricted to modern posterior-stabilized TKA design, recent in silico and in vitro studies supported the negative effect of the lateral overstuffing of the femoral component in the coronal plane during knee flexion. This study provides further evidence that suggest patient-specific anatomical considerations are needed to optimize component position and subsequent outcomes following primary TKA. Additional studies are needed to integrate the rotational status of the femoral component in this analysis. For any figures or tables, please contact authors directly

Introduction. Patients undergoing total knee arthroplasty (TKA) with end-stage osteoarthritis of knee have secondary foot and ankle pathology. Some compensatory changes occur at ankle and subtalar joint secondary to malalignment and deformity at the knee joint. Purpose was to evaluate the changes in hindfoot malalignment and foot deformities in patients with advanced osteoarthritis of knee requiring TKA and effect of correction of knee deformities post TKA on foot/Ankle alignment. Methods. 61 consecutive patients with Kellgren-Lawrence grade IV osteoarthritis knee undergoing TKA were enrolled in a prospective blinded study. Demographic data, deformities at knee and ankle, hindfoot malalignment and functional outcome scores such as VAS, KSS, WOMAC scores, Foot and Ankle Disability Index (FADI) and Foot posture index (FPI) were recorded preoperatively and postoperatively at 6, 12 weeks and final follow up (range: 6–21 months; mean: 14.2months). Results. Statistically significant improvement was observed in KSS score, WOMAC score, FADI and FPI after TKA. There was improvement in ankle valgus after correction of knee varus deformity. Hind foot changes mainly occured at subtalar joint. Hallux valgus (10 patients), and Pesplanus (5 patients) were associated with advanced osteoarthritis of knee. Gait profile score and Gait deviation index improved significantly after TKA. There was increased stance phase and decreased stride length in knee osteoarthritis patients which improved after TKA. Conclusion. Hind foot malalignment with foot deformities (hind foot valgus) occur secondary to knee malalignment and deformities (varus deformity) in advanced osteoarthritis of knee which subsequently improve following TKA

With the success of the medial parapatellar approach (MPA) to total knee arthroplasty (TKA), current research is aimed at reducing iatrogenic microneurovascular and soft tissues damage to the knee. In an effort to avoid disruption to the medial structures of the knee, we propose a novel quadriceps-sparing, subvastus lateralis approach (SLA) to TKA. The aim of the present study is to compare if a SLA can provide adequate exposure of the internal compartment of the knee while reducing soft tissue damage, compared to the MPA. Less disruption of these tissues could translate to better patient outcomes, such as reduced post-operative pain, increased range of motion, reduced instances of patellar maltracking or necrosis, and a shorter recovery time. To determine if adequate exposure could be achieved, the length of the skin incision and perimeter of surgical exposure was compared amongst 22 paired fresh-frozen cadaveric lower limbs (five females/six males) which underwent TKA using the SLA or MPA approach. Additionally, subjective observations which included the percent of visibility of the femoral condyles and tibial plateau, as well as the patellar tracking, were noted in order to qualify adequate exposure. All procedures were conducted by the same surgeon. Subsequently, to determine the extent of soft tissue damage associated with the approaches, an observational assessment of the dynamic and static structures of the knee was performed, in addition to an examination of the microneurovascular structures involved. Dynamic and static structures were assessed by measuring the extent of muscular and ligamentus damage during gross dissection of the internal compartment of the knee. Microneurovascular involvement was evaluated through a microscopic histological examination of the tissue harvested adjacent to the capsular incision. Comparison of the mean exposure perimeter and length of incision was not significantly different between the SLA and the MPA (p>0.05). In fact, on average, the SLA facilitated a 5 mm larger exposure perimeter to the internal compartment, with an 8 mm smaller incision, compared to the MPA, additional investigation is required to assert the clinical implications of these findings. Preliminary analysis of the total visibility of the femoral condyles were comparable between the SLA and MPA, though the tibial plateau visibility appears slightly reduced in the SLA. Analyses of differences in soft tissue damage are in progress. Adequate exposure to the internal compartment of the knee can be achieved using an incision of similar length when the SLA to TKA is performed, compared to the standard MPA. Future studies should evaluate the versatility of the SLA through an examination of specimens with a known degree of knee deformity (valgus or varus)

Background. We have performed total knee arthroplasties for valgus and varus in the knees of one person and investigate the clinical characteristics of these patients and the relationship between the kind of deformity and postoperative result. Methods. From March 2002 to February 2010, 25 patients who had simultaneous varus and valgus knee deformities underwent total knee arthroplasties and followed more than 12 months were included. The average age was 66.9 years and the average follow-up period was 61.1 months. Follow-up imaging assessments were taken and clinical outcome were evaluated using HSS score at last follow-up. Results. 11 cases had more pain in varus knee and 8 cases had more pain in valgus knee preoperatively. In 11 cases, degenerative scoliosis were associated with the knee deformity and among the cases, 10 cases had valgus deformities in concave side of scoliosis. In three cases, hip deformities were noted in ipsilateral side of the valgus deformity. One case showed both hip deformities with ankylosing spondylitis. Preoperative mean valgus angle was 11.4 degree and varus angle was 7.5 degree. Postoperative valgus and varus angle improved to 6.3 and −5.7 degree. HSS score improved from 64.3 to 84.7 point in valgus deformities and from 62.1 to 85.1 point in varus deformities. Postoperative patellar clunk syndrome was identified in one valgus knee, but resolved by arthroscopic debridement. And postoperatively, one case showed out-toeing gait caused by equinovarus deformity in varus knee, but resolved by correction of foot deformity. Conclusions. Simultaneous or staged total knee arthroplasties in patients with simultaneous varus with contralateral valgus knee deformities brought satisfactory outcomes with regard to objective orthopedic criteria such as radiographic and clinical results. Concave aspect of scoliosis and hip deformity correlate with valgus knee in statistically. But rheumatoid factor and VDRL do not correlate with valgus deformity. And we found no significant difference between the kind of deformity and postoperative result

Introduction. Valgus deformity in an end stage osteoarthritic knee can be difficult to correct with no clear consensus on case management. Dependent on if the joint can be reduced and the degree of medial laxity or distension, a surgeon must use their discretion on the correct method for adequate lateral releases. Robotic assisted (RA) technology has been shown to have three dimensional (3D) cut accuracy which could assist with addressing these complex cases. The purpose of this work was to determine the number of soft tissue releases and component orientation of valgus cases performed with RA total knee arthroplasty (TKA). Methods. This study was a retrospective chart review of 72 RATKA cases with valgus deformity pre-operatively performed by a single surgeon from July 2016 to December 2017. Initial and final 3D component alignment, knee balancing gaps, component size, and full or partial releases were collected intraoperatively. Post-operatively, radiographs, adverse events, WOMAC total and KOOS Jr scores were collected at 6 months, 1 year and 2 year post-operatively. Results. Pre-operatively, knee deformities ranged from reducible knees with less than 5mm of medial laxity to up to 12° with fixed flexion contracture. All knees were corrected within 2.5 degrees of mechanical neutral. Average femoral component position was 0.26. o. valgus, and 4.07. o. flexion. Average tibial component position was 0.37. o. valgus, and 2.96. o. slope, where all tibial components were placed in a neutral or valgus orientation. Flexion and extension gaps were within 2mm (mean 1mm) for all knees. Medial and lateral gaps were balanced 100% in extension and 93% in flexion. The average flexion gap was 18.3mm and the average extension gap was 18.7mm. For component size prediction, the surgeon achieved their planned within one size on the femur 93.8% and tibia 100% of the time. The surgeon upsized the femur in 6.2% of cases. Soft tissue releases were reported in one of the cases. At latest follow-up, radiographic evidence suggested well seated and well fixed components. Radiographs also indicated the patella components were tracking well within the trochlear groove. No revision and re-operation is reported. Mean WOMAC total scores were improved from 24±8.3 pre-op to 6.6±4.4 2-year post-op (p<0.01). Mean KOOS scores were improved from 46.8±9.7 pre-op to 88.4±13.5 2-year post-op (p<0.01). Discussion. In this retrospective case review, the surgeon was able to balance the knee with bone resections and avoid disturbing the soft tissue envelope in valgus knees with 1–12° of deformity. To achieve this balance, the femoral component was often adjusted in axial and valgus rotations. This allowed the surgeon to open lateral flexion and extension gaps. While this study has several limitations, RATKA for valgus knees should continue to be investigated. For any figures or tables, please contact authors directly

An osteochondral defect greater than 3cm in diameter and 1cm in depth is best managed by an osteochondral allograft. If there is an associated knee deformity, then an osteotomy is performed. In our series of osteochondral allografts for large post-traumatic knee defects realignment osteotomy is performed about 60% of the time in order to off-load the transplant. To correct varus we realign the proximal tibia with an opening wedge osteotomy. To correct valgus, we realign the distal femur with a closing wedge osteotomy. Our results with osteochondral allografts for the large osteochondral defects of the knee both femur and tibia, have been excellent in 85% of patients at an average follow-up of 10 years. The Kaplan-Meier survivorship at 15 years is 72%. At an average follow-up of 22 years in 58 patients with distal femoral osteochondral allograft, 13 have been revised (22%). The 15-year survivorship was 84%. Retrieval studies of 24 fresh osteochondral grafts obtained at graft revision or conversion total knee replacement at an average of 12 years (5 – 25) revealed the following. In the areas where the graft was still intact, the cartilage was of normal thickness and architecture. Matrix staining was normal except in the superficial and upper mid zones. Chondrocytes were mostly viable but there was chondrocyte clusters and loss of chondrocyte polarity. Host bone had extended to the calcified cartilage but variable remnants of dead bone surrounded by live bone persisted. With a stable osseous base the hyaline cartilage portion of the graft can survive for up to 25 years

Background. Total knee arthroplasty (TKA) is an effective surgical procedure to alleviate excruciating pain and correct dysfunction due to severe knee deformity. The satisfaction rate with current TKA is 80%, While 20% of the patients report uncomfortable feeling during stair descending and deeply knee bending. Preserving the ligaments might allow a restoration close to the natural function, although sacrifice of the ACL is common with the conventional TKA technique. The current bicruciate-retaining (BCR) TKA would be a way to go concerning this issue. This study aimed at evaluating the intraoperative kinematics and joint laxity on BCR TKA if the native function would be replicated and thus assessing the range of motion (ROM) at final followup. Methods. BCR TKAs were performed in 22 knees (12 women, 10 men, average aged 67.2-year-old) with image-free navigation system (Kolibli. TM. ) under general anesthesia. The intraoperative kinematics was evaluated about flexion extension gap (FEG), anterior-posterior translation (APT, bi-condylar rollback) and axial rotation (AR, medial pivot) with passive motion. These kinematic patterns were assessed with the post-operative ROM. Results. There was no paradoxical anterior translation in any cases. The implant kinematics was regulated to the medial pivot motion at early flexion phase and the bi-condylar rollback motion to full flexion angle. The mean flexion was changed from 132 degrees at preoperation to 126 degrees at followup, and the mean flexion contracture improved from 4 degrees to 1 degree. Conclusion. BCR TKA were preserved the nature kinematics including the medial pivot motion and rollback mechanism. Postoperative ROM was quite similar when the preoperative knee flexion was not restricted

An osteochondral defect greater than 3cm in diameter and 1cm in depth is best managed by an osteochondral allograft. If there is an associated knee deformity, then an osteotomy was performed. In our series of osteochondral allografts for large post-traumatic knee defects, realignment osteotomy is performed about 60% of the time in order to off load the transplant. To correct varus we realign the proximal tibia with an opening wedge osteotomy. To correct valgus, we realign the distal femur with a closing wedge osteotomy. Our results with osteochondral allografts for the large osteochondral defects of the knee both femur and tibia, have been excellent in 85% of patients at an average follow-up of 10 years. The Kaplan-Meier survivorship at 15 years is 72%. At an average follow-up of 22 years in 58 patients with distal femoral osteochondral allograft, 13 have been revised (22%). The 15-year survivorship was 84%. Retrieval studies of 24 fresh osteochondral grafts obtained at graft revision or conversion to total knee replacement at an average of 12 years (5 – 25) revealed the following. In the areas where the graft was still intact, the cartilage was of normal thickness and architecture. Matrix staining was normal except in the superficial and upper mid-zones. Chondrocytes were mostly viable but there was chondrocyte clusters and loss of chondrocyte polarity. Host bone had extended to the calcified cartilage but variable remnants of dead bone surrounded by live bone persisted. With a stable osseous base the hyaline cartilage portion of the graft can survive for up to 25 years

Introduction. Intramedullary femoral alignment guide is mostly used in total knee arthroplasty (TKA). Accurate preoperative plan is critical to get good alignments when we use intramedullary femoral guide, because the center of femoral head cannot be looked directly during operation. Commonly, the planning is carried out using preoperative anteroposterior radiographs of the femur. The angles formed between mechanical axes of the femur and distal femoral anatomic axes (AMA) are measured as reference angles of resection of distal femur, and the entry points of intramedullary femoral guide are also planned. The purpose of this study is to investigate the influence of femoral position on radiographic planning in TKA. Materials and Methods. We examined 20 knees of 20 female patients who received TKA. Fourteen patients suffered from primary osteoarthritis of the knees, and 6 suffered from rheumatoid arthritis. Fifteen patients have varus knee deformities and 5 patients have valgus knee deformities. Long leg computed topography scans were performed in all cases before operations, and all images were stored in DICOM file format. The analyses were performed with computer software (3D template, JMM, Osaka, Japan) using DICOM formatted data. The planes containing the center of femoral head and transepicondylar axes were defined as reference planes, and the reference planes were fixed all through analyses. At first, to assess the influence of femoral rotation, the femur was rotated from 30 degrees external rotation to 30 degrees internal rotation in 5 degrees increments in full extension. After that, to examine the influence of knee flexion, the knee was bended from full extension to 30 degrees flexion in 5 degrees increments in neutral rotation. Reconstructed coronal planes parallel to the reference planes were made, the angles between mechanical axes of the femur and distal femoral anatomic axes (AMA) and the distance from entry points to the center of femoral intercondylar notch were measured in each position. The distal anatomic axes were made by connecting the center of femoral canal at 8 centimeters proximal to joint line and that at 16 centimeters proximal to joint line. The entry points of intramedullary femoral guide were defined the points where distal anatomic axes meets intercondylar notch. Results. The mean AMA was 6.8 degrees in neutral position, 7.1 degrees in 10 degrees external rotation, 7.3 in 20 degrees external rotation, 7.2 in 30 degrees external rotation, 6.2 in 10 degrees internal rotation, 5.5 in 20 degrees internal rotation, 4.6 in 30 degrees internal rotation, 6.9 in 10 degrees flexion, 7.2 in 20 degrees flexion, 7.8 in 30 degrees flexion, respectively. The entry points moved 3.9 millimeters laterally in 20 degrees external rotation and 3.6 millimeters medially in 20 degrees internal rotation relative to neutral position. Discussion and Conclusion. Femoral position affected on preoperative planning using anteroposterior radiographs. It is important to get a correct anteroposerior view of total femur, because the femur was easy to rotate in knee disorders

The parameters to be considered in the selection of a cartilage repair strategy are: the diameter of the chondral defect; the depth of the bone defect; the location of the defect (weight bearing); alignment. A chondral defect less than 3 cm in diameter can be managed by surface treatment such as microfracture, autologous chondrocyte transplantation, mosaicplasty, or periosteal grafting. An osteochondral defect less than 3 cm in diameter and less than 1 cm in depth can be managed by autologous chondrocyte transplantation, mosaicplasty or periosteal grafting. An osteochondral defect greater than 3 cm in diameter and 1 cm in depth is best managed by an osteochondral allograft. If there is an associated knee deformity, then an osteotomy should also be performed with all of the aforementioned procedures. In our series of osteochondral allografts for large post-traumatic knee defects realignment osteotomy is performed about 60% of the time in order to off load the transplant. To correct varus we realign the proximal tibia with an opening wedge osteotomy. To correct valgus, we realign the distal femur with a closing wedge osteotomy. Our results with osteochondral allografts for the large osteochondral defects of the knee have been excellent in 85% of patients at an average follow-up of 10 years. The Kaplan-Meier survivorship at 15 years is 72%. At an average follow-up of 22 years in 58 patients with distal femoral osteochondral allograft, 13 have been revised (22%). The 15-year survivorship was 84%. The results for the hip are early. To date we have performed this procedure on 16 patients. Surgical dislocation of the hip is carried out via a trochanteric osteotomy and the defect defined and trephined out. A press-fit fresh osteochondral allograft is inserted using the trephine technique. We have published our early results on a series of 8 patients with 5 good to excellent results, 1 fair result and 2 failures

Introduction. Limb length discrepancy after THA can result in medicolegal litigation. It can create discomfort for the patient and potentially cause back pain or affect the longevity of the implant. Some patients tolerate the length inequality better compared to others despite difference in anatomical femoral length after surgery. Methods and materials. We analyzed the 3D EOS images of 75 consecutive patients who underwent primary unilateral THA (27 men, 48 women). We measured the 3D length of the femur and tibia (anatomical length), the 3D global anatomical length (the sum of femur and tibia anatomical lengths), the 3D functional length (center of the femoral head to center of the ankle), femoral neck-shaft angle, hip-knee-ankle angle, knee flexum/recurvatum angle, sacral slopes and pelvic incidence. We correlated these parameters with the patient perception of the leg length. Results. The values for leg length and pelvic parameters are shown in table 1. 37 patients had a perception of the LLD (49.3%). When the global anatomical length was shorter on the operated side, the perception of the discrepancy was observed in 56% of the cases. In case of anatomical length longer on the operated side, the perception of the discrepancy was described by the patients in 46% of the cases. The LLD perception was correlated with difference in functional length (p=0.0001), pelvic obliquity (p=0.003) and sacral slope (p=0.023). The anatomical femoral length was not correlated with the LLD perception (p=0,008). Discussion. The perception of LLD is a multifactorial complication. We found that the anatomical femoral length (that can be directly affected by the position of the stem) is not the only important factor. The functional length of the lower extremity which can also be affected by the knee deformities is better correlated with the LLD. The pelvic obliquity and version also affect the patient perception of the LLD

Juvenile idiopathic arthritis(JIA) is chronic inflammation commonly occurs in early childhood. Recently, biological therapies are used in JIA at the early stage as same as rheumatoid arthritis, due to retain joint cartilage. However, some of young patients have painful knee problems requiring knee replacement. We experienced 4 cases of JIA treated by knee arthroplasty. The average age at surgery was 33.5 years (range, 26–38 years) with a mean follow-up of 9.5 years (range, 5–18 years). We evaluated the knee range of motion and functional outcomes by the Knee Society Score (KSS), implant selection, postoperative complication, surgery of another joint. Mean range of motion improved from 76.3° (0°–120°) at pre-operation to 110.6° (80°–130°) at post-operation (P<0.05). Mean KSS increased from 47.3 ±20.1 preoperatively to 86.9 ±11.1 (P<0.01) at last follow-up and the mean KSS function from 27.5 ±25.9 to 62.5±20.2 at last follow-up (P<0.05). All of the TKAs were cemented, 5 were cruciate-retaining implant designs, whereas 2 TKAs had constrained posterior stabilized implant designs. Patellar resurfacing was undergone in all knees. Bone graft required in 1 knee within severe knee deformity. Complication were occurred in 5 knees. Medial instability in 2 knees. Skin necrosis, MCL avulsion, recurrence of the synovitis are one in each. All cases had polyarticular type. Previous THA had undergone in 5 hips, synovectomy in 3 knees, foot surgery in 2 feet. At latest follow-up, 1 of 8 TKAs (12.5%) had been revised, and had revision of its polyethylene exchange only. Patients with JIA often have valgus alignment with a flexion contracture and poor bone quality is also frequently compromised. Prescribed immunosuppressive medication or biological agents may cause to infection. In our series there were no infection, but some of these need much more soft tissue release because of severe deformity and flexion contracture. TKA survivorship for JIA is inferior to that typically seen in younger patients with osteoarthritis or rheumatoid arthritis. The knee of conservative therapy were often caused to severe functional limitations. Timimg of TKA may be indicated no matter how young the patient is. Extending timing of TKA may leads to worse outcome and postoperative function. But it may be caution that the surgical exposure can be difficult, because of stiffness, flexion contracture, bony deformity, osteopenia

No, Neutral mechanical axis has never been regarded as “necessary” to the success of TKA. In fact it has never been established as “ideal” with published data. Tibial femoral alignment after TKA is important, but it is also an issue that we do not understand completely. Neutral mechanical alignment refers to the relationship between the mechanical axes of the femur and tibia as shown on full length radiographs. “Neutral” means that these axes are collinear, i.e. that a line may be drawn from the center of the hip to the center of the ankle and it will intersect the center of the knee joint. The allure of the “straight line” has led many surgeons to regard a neutral mechanical axis as “perfection” for TKA surgery, but indeed, it is not the usual “normal” alignment for most human knees, nor is it the target for many conventional knee replacements. The “neutral mechanical axis” represents OVERCORRECTION for most knees. Moreland demonstrated in 1987 that few human knee joints are naturally aligned “in neutral”, but with the line from center of hip to center of ankle passing through the medial compartment. This tendency to relative varus mechanical axis in most human knees was corroborated by Bellemans et al in 2012. They substituted the word “constitutional varus” for what would otherwise be known as “normal alignment”. In general, patients with pathologic or significant varus alignment, whose arthroplasties have been performed competently, are at greatest risk for failure by wear, osteolysis and loosening. This is the prototypical failure mechanism that pre-occupied the surgeons responsible for making knee arthroplasty successful in the 1970s. The first paper to identify varus TKA alignment and failure due to loosening was Lotke and Ecker in 1977. They worked from short radiographs and ushered in an era of careful attention to valgus TKA alignment-not neutral alignment. Correction of varus deformity combined with ligament balancing was probably responsible for making condylar type knee arthroplasties work durably in the early days. Full length radiographs, used by Kennedy and White in 1987 to study alignment in unicompartmental arthroplasties, provide a more sophisticated method of evaluating knee alignment. These studies must be aligned with correct rotation to be valid. Computerised navigation was probably responsible for some surgeon's dedication to the neutral mechanical axis. The study of Parratte et al from Mayo has received much attention and argued that a neutral mechanical axis did NOT improve success rates at 15 years. It should be noted that these TKA's were expertly performed and even the less well-aligned cases were not “excessively” malaligned. This study does not state that alignment is irrelevant to the success of TKA, but rather that a range of alignments (with stability) might be expected to produce a durable arthroplasty. Concurrent with these developments has been an interest in “under-correcting” knee deformity or allowing osseous anatomy (with compensation for cartilage loss) guide component position. In truth, it is inaccurate to describe conventional “align and balance” techniques as necessarily seeking a neutral mechanical axis. Most classical alignment techniques do, however, alter the angle of component position from the original articular surface angles and theoretically may not function as well with the native soft tissue environment. Surgeons who would align the TKA identically to the arthritic knee may credit previous generations with improving the technology such that this is a possibility. If every patient is to be aligned with this technique, however, this suggests that soft tissue pathology does not exist. As with all complex issues, glib answers are to be avoided and deep analysis is appropriate

Purpose. There is a large gap between UKA and TKA in terms of tissue preservation including bone stock and knee ligament. We have recently introduced bicompartmental UKA (Bi-UKA) to fill the gap and achieve more “physiological” knee than TKA. In this study, we report the short-term results of Bi-UKA. Subjects and Methods. Thirty knees in twenty-nine osteoarthritis patients who underwent Bi-UKA from December 2010 to December 2013 (6 males and 23 females, average age of 75) were clinically and radiologically evaluated with an average observation period of 19 months. The operative indications were (1)confirmed diagnosis of medial and lateral osteoarthritis or osteonecrosis with preserved status of patellofemoral joint; (2)range of knee flexion greater than 110°; (3)flexion contracture less than 20°; (4)clinically stable knee in the frontal and sagittal plane; (5)correctable knee deformity with fine knee congruency. In all cases, fixed type UKA was implanted through a tibia dependent cut using a spacer block. Zimmer Uni and TRIBRID UKA (Kyocera Medical Corporation) were implanted in 18 and 12 cases, respectively. Results. The mean JOA score improved significantly from 57 points preoperatively to 89 points postoperatively. With regard to ROM, the mean extension significantly improved from −6° to −1° (p<0.001), and the mean flexion was almost unchanged from 134° to 139°. Six knees achieved maximum flexion angles of more than 150°. The mean leg alignment was unchanged from 174.5° to 175.2°, although there were five knees in which alignment was corrected by more than 10° after the surgery. All implant alingnments were reasonably acceptable and particularly, the gaps of setting angle between medial and lateral components were quite small in lateral view radiograph. A only major postoperative complication we have experienced was a periprosthetic tibia fracture, which had been successfully treated with screw fixation. Discussion. Bi-UKA is a bone- and ligament-sparing procedure that may provide better knee function and patient satisfaction than does TKA. Complicated surgical procedure, relationship of placement position between medial and lateral prostheses, ligament balancing, and longer-term results remain subjects to be resolved. However, tibia dependent cut technique using spacer block was quite useful to improve the accuracy of implants positioning during Bi-UKA procedure. Our short-term results of Bi-UKA were well acceptable although there were a few complaints or complications. We would like to confirm the usefulness of this procedure and further establish the best indication by increasing the number of patients in the future

Introduction. Clinical outcomes for total knee arthroplasty (TKA) are especially sensitive to lower extremity alignment and implant positioning. 1. The use of computer-assisted orthopaedic surgery (CAOS) can improve overall TKA accuracy. 2. This study assessed the accuracy of an image-free CAOS guidance system (Exactech GPS, Blue-Ortho, Grenoble, FR) in both a synthetic leg with a normal mechanical axis and legs with abnormal mechanical axis. Materials and methods. A high-resolution 3D scanner (Comet L3D, Steinbichler, Plymouth, MI) was used to scan varus-deformed (n=12), neutral (n=12), and valgus-deformed (n=4) knee inserts (Mita M-00566, M-00598, M-00567; respectively, Medical Models, Bristol, UK) and collect pre-identified anatomical landmarks prior to using the models to simulate knee surgery. The image-free CAOS guidance system was then used to acquire the same landmarks. After adjusting the position and orientation of the cutting block to match the targets, bone resections were performed, and the knee models were re-scanned. The 3D scans made before and after the cuts were overlaid and the resection parameters calculated using the pre-identified anatomical landmark data and advanced software (UG NX, Siemens PLM, Plano, TX). Data sets obtained from the 3D scanner (see Figure 1A) were compared with data sets from the guidance system (see Figure 1B). Given the accuracy of the 3D scanner (<50μm), its measurements were used as the baseline for assessing CAOS system error. Results. Table I shows errors in bone resection thickness orientation measurement errors as well as CAOS system confidence intervals (CI) for both the tibia and femur, depending on deformity type. Regardless of knee deformity and other parameters, the mean error of the CAOS system was systematically less than 0.5 mm for bone resection measurements and 1° for joint angle measurements. The 95% CI were in the range of −1.54 to 0.67mm for bone resection measurements and −0.64° to 1.67° for joint angle measurements. No statistical differences were detected between different deformity groups in the Error Indexes for both the tibia and femur. Discussion. This study represents an extension of a previous evaluation of the same CAOS system, where only a limited number of neutral models (n=6) were investigated. The current study was performed to reassess the accuracy and precision of the CAOS system using the same methodology with a larger number of knee models (n=28) exhibiting different types of deformities affecting the mechanical axis. In conclusion, this study demonstrates a high level of in-vitro accuracy for the CAOS system, regardless of leg-alignment deformity type. The mean error of the CAOS system, characterized as the difference between the measured and checked values, was systematically less than 0.5 mm for bone resection measurements and 1° for joint angle measurements

Backgrounds. Most of in vivo kinematic studies of total knee arthroplasty (TKA) have reported on varus knee. TKA for the valgus knee deformity is a surgical challenge. The purposes of the current study are to analyze the in vivo kinematic motion and to compare kinematic patterns between weight-bearing (WB) and non-weight-bearing (NWB) knee flexion in posterior-stabilized (PS) fixed-bearing TKA with pre-operative valgus deformity. Methods. A total of sixteen valgus knees in 12 cases that underwent TKA with Scorpio NRG PS knee prosthesis operated by modified gap balancing technique were evaluated. The mean preoperative femorotibial angle (FTA) was 156°±4.2°. During the surgery, distal femur and proximal tibia was cut perpendicular to the mechanical axis of each bone. After excision of the menisci and cruciate ligaments, balancer (Stryker joint dependent kinematics balancer) was inserted into the gap between both bones for evaluation of extension gap. Lateral release was performed in extension. Iliotibial bundle (ITB) was released from Gerdy tubercle then posterolateral capsule was released at the level of the proximal tibial cut surface. If still unbalanced, pie-crust ITB from inside-out was added at 1 cm above joint line until an even lateral and medial gap had been achieved. Flexion gap balance was obtained predominantly by the bone cut of the posterior femoral condyle. Good postoperative stability in extension and flexion was confirmed by stress roentgenogram and axial radiography of the distal femur. We evaluated the in vivo kinematics of the knee using fluoroscopy and femorotibial translation relative to the tibial tray using a 2-dimentional to 3-dimensional registration technique. Results. The average flexion angle was 111.3°±7.5° in weight-bearing and 114.9°±8.4° in non-weight-bearing. The femoral component demonstrated a mean external rotation of 5.9°±5.8° in weight-bearing and 7.4°±5.2° in non-weight-bearing (Fig.1). In weight-bearing, the femoral component showed medial pivot pattern from 0° to midflexion and a bicondylar rollback pattern from midflexion to full flexion (Fig2). Medial condyle moved similarly in non-weight-bearing condition and in weight-bearing condition. Lateral condyle moved posterior in slightly earlier angle during weight-bearing condition than during non-weight-bearing condition (Fig.3). Discussion. Numerous kinematic analyses of a normal knee have demonstrated greater posterior motion of the lateral femoral condyle relative to the medial condyle, leading to a mean external rotation and a bicondylar rollback motion with progressive knee flexion. A kinematic analysis of valgus knee was reported to show a different kinematic pattern from a physiological knee motion. Many valgus knees showed paradoxical anterior translation from extension to mid-flexion and greater posterior translation in the medial condyle than in the lateral condyle. Kitagawa et al. reported that this non-physiologic pattern wasn't completely restored after TKA using medial pivot knee system. In the present study, we showed kinematic patterns of the TKA performed on the valgus knee to be similar to the normal knee for the first time, even though the magnitude of external rotation was small. Conclusions. We conclude that the medial pivot pattern followed by posterior rollback motion can be obtained in TKA with modified gap balancing technique for the preoperative valgus deformity

Patients planning to undergo total knee arthroplasty (TKA), especially in Asian and Middle Eastern countries, usually expect to be able to perform activities requiring knee flexion such as sitting cross-legged or kneeling with ease after the surgery. Postoperative range of motion (ROM) can be affected by multiple factors such as the patient's gender, age, preoperative ROM, diagnosis, the surgeon's technique, the pre- and post-operative rehabilitation program, and the design of the prosthesis. Among these, the choice of the prosthesis depends on the surgeon's preference. As a result, several trials and studies have been conducted to improve postoperative ROM by modifying prosthesis design. The present study aimed to examine the results of TKA with the NexGen LPS-Flex system (Zimmer, Warsaw, Indiana), which is one of several high-flexion total knee prostheses that were designed to achieve a wide ROM for osteoarthritis in the valgus knee. A total of 27 primary TKAs in 26 osteoarthritis patients with valgus knee deformities (femorotibial angle (FTA) ≤ 170°) were performed using the NexGen LPS-Flex fixed prosthesis between July 2003 and December 2011. The patients included 2 men (7.7%, 2 knees) and 24 women (92.3%, 25 knees) with a mean age of 72.6 years (range, 59 to 83 years) at the time of the surgery. The mean duration of follow-up after surgery was 50.1 months (range, 24 to 126 months). Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), maximum flexion angle, maximum extension angle, and radiological femorotibial angle (FTA) were evaluated pre- and post-operatively. The mean preoperative KSKS and KSFS were 42.6 points (SD 7.5) and 41.1 points (SD 8.6), respectively, which improved after surgery to 82.2 points (SD 8.2) and 80.9 points (SD 7.6), respectively (P < 0.01). The maximum flexion angle improved from 109.1° (SD 23.1) to 117.3° (SD 12.4) postoperatively, but it did not reach statistical significance (P = 0.097). The preoperative maximum extension angle improved from −9.7° (SD 10.8) to −3.6° (SD 4.9) postoperatively (p < 0.05). The mean radiological FTA was 166.4° (SD 4.2; range: 155° − 170°) preoperatively and 172.4° (SD 2.7; range: 168° − 178°) at the final follow-up, and the difference was statistically significant (P < 0.01). None of the patients had undergone revision surgery by the final follow-up. As a conclusion, the results of the present study showed that the use of NexGen LPS-Flex implant in TKA for knee osteoarthritis with valgus deformity produced a satisfactory improvement in the clinical and radiological outcomes. Further studies on the outcomes of other prosthesis are needed to determine whether the NexGen LPS-Flex implant is advantageous for osteoarthritis patients with valgus knees who undergo TKA, and further large-scale studies with longer term follow-up are necessary to verify our results