Introduction. A large number of total knee arthroplasty (TKA) patients, particularly in Japan, India and the Middle East, exhibit anatomy with substantial proximal tibial torsion. Alignment of the tibial components with the standard anterior-posterior (A-P) axis of the tibia can result in excessive external rotation of the tibial components with respect to femoral component alignment. This in turn influences patellofemoral (PF) mechanics and forces required by the extensor mechanism. The purpose of the current study was to determine if a rotating-platform (RP) TKA design with an anatomic patellar component reduced compromise to the patellar tendon, quadriceps muscles and PF mechanics when compared to a fixed-bearing (FB) design with a standard dome-shaped patellar component. Methods. A dynamic three-dimensional finite element model of the knee joint was developed and used to simulate a deep knee bend in a patient with excessive external tibial torsion (Figure 1). Detailed description of the model has been previously published [1]. The model included femur, tibia and patellar bones, TKA components, patellar ligament, quadriceps muscles, PF ligaments, and nine primary ligaments spanning the TF joint. The model was virtually implanted with two contemporary TKA designs; a FB design with domed patella, and a RP design with anatomic patella. The FB design was implanted in two different alignment conditions; alignment to the tibial A-P axis, and optimal alignment for bone coverage. Four different loading conditions (varying internal-external (I-E) torque and A-P force) were applied to the model to simulate physiological loads during a deep knee bend. Quadriceps muscle force, patellar tendon force, and PF and TF joint forces were compared between designs. Results. The RP design demonstrated consistently lower medial-lateral (M-L) force at the PF joint than the FB design, with greater differences between designs in later flexion once the patella was engaged in the sulcus groove; root-mean-square (RMS) differences in M-L force averaged 50 N less in the RP design throughout the flexion cycle, and 70 N less after 45° flexion (Figure 2). The FB design aligned for optimal bone coverage demonstrated 15% higher M-L forces than the FB design aligned with the tibial A-P axis. RMS load required by the quadriceps muscle was 60 N lower with the RP design than the FB design throughout the cycle (Figure 2). Discussion. Comparing a RP design with an anatomic patellar component and a FB design with a domed patellar component, the RP design demonstrated lower M-L PF joint and soft-tissue extensor mechanism forces. Differences were more pronounced under conditions of high I-E torque where the RP design accommodated large relative TF rotation. Differences in FB alignment resulted in substantially different PF M-L forces; when the FB component was mal-aligned with respect to the tibial A-P axis (and the line-of-action of the patellar tendon) the resulting M-L PF force was increased. The RP design reduced the demands on the extensor mechanism and loads on the PF joint and facilitated better coverage of the resected tibial bone surface

Background. Authors sought to determine the degree of lateral condylar hypoplasia of distal femur was related to degree of valgus malalignment of lower extremity in patients who underwent TKA. Authors also examined the relationships between degree of valgus malalignment and degree of femoral anteversion or tibial torsion. Methods. This retrospective study included 211 patients (422 lower extremities). Alignment of lower extremity was determined using mechanical tibiofemoral angle (mTFA) measured from standing full-limb AP radiography. mTFA was described positive value when it was valgus. Patients were divided into three groups by mTFA; more than 3 degrees of valgus (valgus group, n = 31), between 3 degrees of valgus to 3 degrees of varus (neutral group, n = 78), and more than 3 degrees of varus (varus group, n = 313). Condylar twisting angle (CTA) was used to measure degree of the lateral femoral condylar hypoplasia. CTA was defined as the angle between clinical transepicondylar axis (TEA) and posterior condylar axis (PCA). Femoral anteversion was measured by two methods. One was the angle formed between the line intersecting femoral neck and the PCA (pFeAV). The other was the angle formed between the line intersecting femoral neck and clinical TEA (tFeAV). Tibial torsion was defined as a degree of torsion of distal tibia relative to proximal tibia. It was determined by the angle formed between the line connecting posterior cortices of proximal tibial condyles and the line connecting the most prominent points of lateral and medial malleolus. Positive values represented relative external rotation. Negative values represented relative internal rotation. Results. Greater lateral femoral condylar hypoplasia was related to increased valgus alignment of lower extremity. Correlation coefficient between mTFA and CTA was 0.253 (p < 0.001). Valgus group showed increased CTA, which was 10.2° ± 1.9°. CTA was 7.4° ± 2.5° in neutral group and 6.6° ± 4.8° in varus group. There was significant positive correlation between the degree of valgus alignment and the degree of femoral anteversion (r = 0.145, p = 0.003). pFeAV was 16.7° ± 5.8° in valgus group, 12.1° ± 6.0° in neutral group and 10.9° ± 7.0° in varus group. There was no correlation between degree of valgus alignment and degree of femoral anteversion (r = 0.060, p = 0.218). In terms of tibial torsion, increased valgus malalignment was associated with increased tibial torsion (r = 0.374, p < 0.001). Valgus group showed increased tibial torsion than other groups. Tibial torsion was 32.6° ± 6.2° in valgus group, 26.3° ± 6.9° in neutral group and 22.6° ± 7.2° in varus group. Conclusions. Increased valgus alignment of lower extremity was related to greater lateral femoral condylar hypoplasia. However, increased valgus alignment was not related to degree of femoral anteversion whereas it was related to increased external tibial torsion. Our findings should be considered when determining proper rotational alignment in TKA

Introduction. Snapping hip syndrome is a common condition affecting 10% of the population. It is due to the advance of the iliotibial band (ITB) over the greater trochanter during lower limb movements and often associated with hip overuse, such as in athletic activities. Management is commonly conservative with physiotherapy or can be surgical to release the ITB. Here we carry out a systematic review into published surgical management and present a case report on an overlooked cause of paediatric snapping hip syndrome. Materials & Methods. A systematic review looking at published surgical management of snapping hip was performed according to PRISMA guidelines. PubMed, MEDLINE, EMBASE, CINAHL and the Cochrane Library databases were searched for “((Snapping hip OR Iliotibial band syndrome OR ITB syndrome) AND (Management OR treatment))”. Adult and paediatric published studies were included as few results were found on paediatric snapping hip alone. Results. 1548 studies were screened by 2 independent reviewers. 8 studies were included with a total of 134 cases, with an age range of 14–71 years. Surgical management ranged from arthroscopic, open or ultrasound guided release of the ITB, as well as gluteal muscle releases. Common outcome measures showed statistically significant improvement pre- and post-operatively in visual analogue pain score (VAPS) and the Harris Hip Score (HHS). VAPS improved from an average of 6.77 to 0.3 (t-test p value <0.0001) and the HHS improved from an average of 62.6 to 89.4 (t-test p value <0.0001). Conclusions. Although good surgical outcomes have been reported, no study has reported on the effect of rotational profile of the lower limbs and snapping hip syndrome. We present the case of a 13-year-old female with snapping hip syndrome and trochanteric pain. Ultrasound confirmed external snapping hip with normal soft tissue morphology and radiographs confirmed no structural abnormalities. Following extensive physiotherapy and little improvement, she presented again aged 17 with concurrent anterior knee pain, patella mal-tracking and an asymmetrical out-toeing gait. CT rotational profile showed 2° of femoral neck retroversion and excessive external tibial torsion of 52°. Consequently, during her gait cycle, in order to correct her increased foot progression angle, the hip has to internally rotate approximately 35–40°, putting the greater trochanter in an anterolateral position in stance phase. This causes the ITB to snap over her abnormally positioned greater trochanter. Therefore, to correct rotational limb alignment, a proximal tibial de-rotation osteotomy was performed with 25° internal rotation correction. Post-operatively the patient recovered well, HHS score improved from 52.5 to 93.75 and her snapping hip has resolved. This study highlights the importance of relevant assessment and investigation of lower limb rotational profile when exploring causes of external snapping hip, especially where ultrasound and radiographs show no significant pathology

Introduction. Torsional malalignment syndrome (TMS) is a unique combination of rotational deformities in the lower limb, often leading to severe patellofemoral joint pain and disability. Surgical management of this condition usually consists of two osteotomies in each affected limb, with simultaneous correction of both femoral anteversion and external tibial torsion. However, we believe that a single supratubercular osteotomy followed by tibial derotation with the Taylor Spatial Frame (TSF) can be used to provide a significant improvement in both appearance and function. Materials and Methods. This is a retrospective case analysis in which we will be reviewing 16 osteotomies performed by one surgeon between 2006 and 2017. The study includes 11 patients with a mean age of 16.7 ± 0.8 years. Pre and post-operatively, patients were fully evaluated through history and physical examination, and CT rotational profiling. Statistical analyses were performed in order to determine whether or not any observed clinical or cosmetic improvements were statistically significant. Results. The results show significant improvements in scores reported on post-operative functional assessment, with mean Oxford Knee Score (OKS) increasing by 18.3 and mean Kujala Anterior Knee Pain Scale (AKPS) also increasing by 31.4. In addition to this, post-operative clinical assessment showed a reduced thigh-foot angle (TFA) in all cases, by a mean value of 31.9o. The angle of the transmalleolar axis (TMA) was successfully reduced in 14/16 cases, by a mean value of 8.6o. Statistical analysis showed all of these results to be statistically significant where p<0.05. Conclusions. The results show that supratubercular osteotomy, followed by gradual correction with TSF, can be used to provide a significant improvement in both appearance and function for patients suffering from TMS

Although optimal alignment is essential for improved function and implant longevity after TKA, we have less bony landmarks of tibia relative to femur. Trans-malleolar axis (TMA) is a reference line of distal tibia in the axial plane, which externally rotated relative to a ML axis of proximal tibia. We originally defined another reference axis associated with the orientation of tibial plafond, and then measured tibial torsion in the 3D-coordinate system. Three-dimensional CAD models of 20 tibiae were reconstructed based on pre-operative CT data from OA patients (16 females and 4 males, 73.8 ± 6.9 years old). TMA was a line connecting each apex of medial and lateral malleolus. The plafond axis (PLA) that we originally defined in this study was a line connecting each midpoint of medial and lateral margin of talocrural facet. In terms of interobserver correlation coefficiency and mean errors of the designated points to define those axes, TMA was found out to be 0.982, 3.14 ± 0.47 mm (medial), and 0.988, 4.88 ± 0.59 mm (lateral). Those of PLA were 0.997, 1.97 ± 0.53 mm (medial), and 0.995, 2.02 ± 0.44 mm (lateral). The tibial torsion was 16.3 ± 6.3°with reference to TMA, and 10.2 ± 8.4°to PLA. Based on these results, as for the rotational reference axis in the axial plain of distal tibia, we consider the plafond axis to be another reliable and reproducible axis, which is expected to be applicable in preoperative planning in TKA to reduce outliers of coronal alignment

Good clinical outcomes of Total Knee Arthroplasty (TKA) demand the ability to plan a surgery precisely and measure the outcome accurately. In comparison with plain radiograph, CT-based 3D planning offers several advantages. More specifically, CT has the benefits of avoiding errors resulting from magnification and inaccurate patient positioning. Additional benefits include the assessment in the axial plane and the replacement of 2D projections with 3D data. The concern on 3D CT-based planning, however, lies in the increase of radiation dosage to the patients. An alternative is to reconstruct a patient-specific 3D model of the complete lower extremity from 2D X-ray radiographs. This study presents a clinical validation of a novel technology called “3XPlan” which allows for 3D prosthesis planning using 2D X-ray radiographs. After a local institution review board (IRB) approval, 3XPlan was evaluated on 24 patients TKA. Pre-operatively, all the patients underwent a CT scan according to a standard protocol. Image acquisition consisted of three separate short spiral axial scans: 1) ipsilateral hip, 2) affected knee and 3) ipsilateral ankle. All the CT images were segmented to extract 3D surface models of both femur and tibia, which were regarded as the ground truth. Additionally, 2 X-ray images were acquired for each affected leg and were used in 3XPlan to derive patient-specific models of the leg. For 3D models derived from both modalities (CT vs. X-ray), five most relevant anatomical parameters for planning TKA were measured and compared with each other. Except for tibial torsion, the average differences for all other anatomical parameters are smaller than or close to 3 degrees

Introduction. The aim of the present study was to evaluate the discrepancies of rotational profiles of whole limb between operated and non-operated limb following unilateral total knee arthroplasty. Materials and Methods. We conducted an analysis the CT data from 32 patients undergoing primary unilateral total knee arthroplasty using measured resection technique, which femoral component was always implanted with external rotation to posterocondylar axis from July 2009 to April 2013. Using these CT scan, rotational profiles of total limb such as femoral torsion angle (femoral neck anteversion angle; FTA), tibial torsion angle (TTA), knee joint rotation angle (KJRA) and total limb rotation (TLR) were measured. Results. There were significant discrepancies of FTA and KJRA between operated and non-operated limb following unilateral total knee arthroplasty. The mean difference of operated and non-operated side for FTA and KJRA were −6.51 ± 11.88º (p=0.0041) and −6.83 ± 5.04º (p < 0.001) respectively. However, there were no significant discrepancies of TLR, TTA. TTA and TLR showed strong correlation (r= 0.7309). Conclusion. FTA showed significant side to side discrepancy, TTA and TLR showed no significant discrepancy between operated- and non-operated limbs in patients undergone unilateral TKA. These results are due to the compensation effect of KJRA. However, excessive external rotation of femoral component beyond the compensation effect of prosthetic knee joint can lead to total limb rotational discrepancy in patient undergoing unilateral total knee arthroplasty

Background. A careful consideration of change of the rotational profiles of total limb after unilateral total knee arthroplasty is necessary. The aim of the present study was to evaluate the discrepancies of rotational profiles of total limb between operated and non-operated limb following unilateral total knee arthroplasty. Methods. We conducted a retrospective analysis the CT data from 32 patients undergoing primary unilateral total knee arthroplasty using measured resection technique, which femur implant was applied at an external rotation of 3° relative to the posterior condylar axis from July 2009 to April 2013 in our hospital. Using these CT studies, rotational profiles of total limb such as femoral torsion angle (femoral neck anteversion angle; FTA), tibial torsion angle (TTA), neck-malleolar angle (NMA), knee joint rotation angle (rotational mismatch; KJRA) and total limb rotation (TLR) were measured. Results. There were significant discrepancies of FTA and KJRA between operated and non-operated limb following unilateral total knee arthroplasty. The mean difference of operated and non-operated side for FTA and KJRA were −6.5 ± 11.9° (p=0.004) and −6.8 ± 5.0° (p < 0.001) respectively. However, there were no significant discrepancies of TLR, TTA and NMA. Conclusion. With comparison with non-operated side, although FTA is significantly decreased in operated limb than non-operated limb following total knee arthroplasty, there were no significant discrepancies of NMA and TLR, because of the compensatory effect of KJRA. However, excessive external rotation of femur implant can affect adversely on rotational profiles of total limb. Further long term studies will be required to evaluate the change of the rotational profiles following unilateral total knee arthroplasty

Introduction. Version abnormalities of the femur, either retroversion or excessive anteversion, cause pain and hip joint damage due to impingement or instability respectively. A retrospective clinical review was conducted on patients undergoing a subtrochanteric derotation osteotomy for either excessive anteversion or retroversion of the femur. Methods. A total of 49 derotation osteotomies were performed in 39 patients. There were 32 females and 7 males. Average age was 29 years (range 14 to 59 years). Osteotomies were performed closed with an intramedullary saw (Figure 1). Fixation was performed with a variety of intramedullary nails. Patients requiring a varus or valgus intertrochanteric osteotomy were excluded. Pure rotational corrections only were performed. Twenty-four percent of patients had a retroversion deformity (average −8° retroversion, range +1 to −23°), 76% had excessive anteversion of the femur (average +36° anteversion, range +22° to +53°). Etiology was post-traumatic in 5 (10%), diplegic cerebral palsy in 4 (8%), fibrous dysplasia in 2 (4%), Prader-Willi Syndrome in 1 (2%) and idiopathic in 37 (76%). Previous surgery had been performed in 51% of hips. Fifty-seven percent underwent concomitant surgery with the index femoral derotation osteotomy, including hip arthroscopy in 39% (labral debridement alone or with femoral neck osteochondroplasty), a tibial derotation osteotomy in 12% and periacetabular osteotomy in 6%. Concomitant tibial osteotomies were performed to correct a compensatory excessive external tibial torsion that would be exacerbated in the correction of excessive femoral anteversion. The modified Harris Hip Score was used to assess the results in patients with a minimum of 24 months follow-up. Results. There were no non-unions. Average time to union was 3.3 months. One late infection occurred 10 months after surgery, treated successfully with hardware removal and antibiotics. Two patients, one with Prader-Willi syndrome and one with Ehlers-Danlos syndrome, were converted to total hip replacement. At an average follow-up of 6.1 years (range 2 to 19.1 years), the modified Harris Hip Score improved by 26 points (p< 0.001, Wilcoxon signed-ranks test). The results were rated as excellent in 71%, good in 22%, fair in 5% and poor in 3%. Subsequent surgery was required in 73%, 93% of which were hardware removals. Discussion and Conclusion. A closed, subtrochanteric derotation osteotomy of the femur is a safe and effective procedure to treat either femoral retroversion or excessive anteversion. Excellent or good results were obtained in 93%, despite the need for subsequent hardware removal in more than two-thirds of the patients. For figures/tables, please contact authors directly.

Hinges were used early in total knee replacement history. The stems were too short, the trochlear groove was absent or inadequate and the mechanism lacked strength. Hinges, therefore, acquired a very bad reputation. As the only stems in early knees were on hinges, I used them when necessary, i.e. a completely missing medial collateral ligament, a flexion gap of more than three centimeters with a normal extension gap and missing bone. I used a Guepar II and my results were good up to 20 years when the plastic wore out and the spindle was damaged. By that time, new spindles were not available and the cases had to be revised. Revision of a cemented bowed stem is a nightmare. One would wish, therefore, to have a design, where the bearings could be detached from the stems and a new bearing inserted. The main problem with hinges nowadays is that they all rotate, or at any rate, all the hinges which I can get, rotate. The commonest indication for a hinge is the multiply revised knee due to missed tibial torsion. A rotating hinge used in a situation like this results in the patient externally rotating the tibia and subluxating or dislocating the patella. They, therefore, cannot use this knee as the leading leg on any activity and they may have instability or falls as a result of the patellar dislocation. It is not difficult to block rotation but, so far as I know, no one has done it. Is there a role for hinge? Very seldom and not with the existing designs

Background:. Tibia Vara (Blount's disease) is characterized by a growth disturbance of the posteromedial proximal tibial physis. This results in the typically complex tibial deformity of varus, procurvatum and internal tibial torsion. Knee instability is due to medial tibial joint depression and lateral ligament complex attenuation. Femoral angular and rotational deformity are associated features. Obesity often complicates management. Langenskiöld observed six stages of the disorder on X-ray (stage 6 not occurring before 9 years) and obtained good results with proximal tibial realignment osteotomy if performed before the age of 8 years. Our experience is very different. Purpose:. To evaluate our experience with treatment of a consecutive cohort of patients with early onset Blount's disease in terms of clinical findings, recurrence rate and factors associated with recurrence and treatment methods and indications. Methods:. A retrospective chart and imaging review was completed of 100 extremities (58 patients) treated surgically for early onset Blount's disease. Follow-up ranged between 1 and 7 years. Results:. These children all presented with a history of onset of deformity between the ages of 1 and 3 years. Their age at first treatment varied between 2 and 10 years. Langenskiöld stage V and VI occurred in younger patients than originally described. The recurrence rate of extremities treated with simple osteotomy was 42% (25/58). Factors associated with recurrence include age >4 (p<0.001), obesity (p=0.007), instability (p=0.003), severity of deformity (femoro-tibial angle) (p<0.001), medial physeal slope (p<0.001) and advanced Langenskiöld stage (p<0.001). Surgical treatment included the use of growth retardation alone, dome realignment osteotomy with and without growth retardation, oblique proximal tibial (Rab) osteotomy, 3-in-1 procedure (medial elevation, tibial osteotomy and lateral epiphyseodesis) and gradual correction with hexapod fixators was used in some recurrent cases. In addition we describe a new surgical technique which obtains acute deformity correction at the level of the growth plate. Conclusion:. We propose that the disease follows a more aggressive course in the black population of Kwa-Zulu Natal, South Africa. The management is often complex and recurrence is not uncommon

Introduction. The assessment of leg length is essential for planning the correction of deformities and for the compensation of length discrepancy, especially after hip or knee arthroplasty. CT scan measures the “anatomical” lengths but does not evaluate the “functional” length experienced by the patients in standing position. Functional length integrates frontal orientation, flexion or hyperextension. EOS system provides simultaneously AP and lateral measures in standing position and thus provides anatomical and functional evaluations of the lower limb lengths. The objective of this study was to measure 2D and 3D anatomical and functional lengths, to verify whether these measures are different and to evaluate the parameters significantly influencing these potential differences. Material and Methods. 70 patients without previous surgery of the lower limbs (140 lower extremities) were evaluated on EOS images obtained in bipodal standing position according to a previously described protocol. We used the following definitions:. anatomical femoral length between the center of the femoral head (A) and center of the trochlea (B). anatomical tibial length between the center tibial spine (intercondylar eminence) (C) and the center of the ankle joint (D). functional length is AD. global anatomical length is AB + CD. Other parameters measured are HKA, HKS, femoral and tibial mechanical angles (FMA, TMA), angles of flexion or hyperextension of the knee, femoral and tibial torsion, femoro-tibial torsion in the knee, and cumulative torsional index (CTI). All 2D et3D measures were evaluated and compared for their repeatability. Results. Regarding repeatability, an ICC> 0.95 was found for all measurements except for the tibial mechanical angle (0.91 for 2D, 3D 0.92 for 3D). We observed 54/140 lower limbs with Flessum/Recurvatum angles (FRA) >10°. 2D results (mean, SD) were. 41,8mm(2,9) for femoral anatomical length. 36,1mm(2,8) for tibial anatomical length. 78,0mm(5,4) for global anatomical length. 78,5 mm(5,5) for functional length. 7,4°(12,0) for Flessum/Recurvatum angle. −1,5°(6,4) for HKA. 4,9°(2,0) for HKS. 92,1°(3,4) for FMA. 87,1°(3,4) for TMA. 3D results (mean, SD) were. 42,4mm (2,8) for femoral anatomical length. 36,6mm (2,8) for tibial anatomical length. 79,0mm (5,4) for global anatomical length. 78,9mm (5,5) for functional length. 7,2°(12,0) for Flessum/Recurvatum angle. −1,0°(5,9) for HKA. 4,9°(1,5) for HKS. 92,7°(2,7) for FMA. 87,9°(3,9) for TMA. The 2D/3D measurements of functional lengths were statistically significant (p <0.0001. Student's test). For anatomical lengths. 2D/3D measurements were also statistically significant (p <0.0001. Student's test for femoral tibial and global anatomical lengths). Some parameters significantly influenced 2D/3D differences:. for the global anatomical length: FRA P<0,0001, TMA P=0,0173, HKA P=0,0259 and femoro-tibial torsion P=0,0026. for the functional length FRA P=0,0065. Discussion and conclusion. EOS imaging allows to accurately assess the anatomical and functional length experienced by the patient. These new data open new perspectives for planning length or axis corrections and for an optimized evaluation in some medico legal issues after joint replacement or posttraumatic sequelae. This study points out the importance of 3D measurements in outliers cases (varus or valgus cases, flessum or recurvatum of the knee)