In the vast majority of patients, the anatomical and mechanical axes of the tibia in the coronal plane are widely accepted to be equivalent. This philosophy guides the design and placement of orthopaedic implants within the tibia and in both the knee and ankle joints. However, the presence of coronal tibial bowing may result in a difference between these two axes and hence cause suboptimal placement of implanted prostheses. Although the prevalence of tibial bowing in adults has been reported in Asian populations, to date no exploration of this phenomenon in a Western population has been conducted. The aim of this study was to quantify the prevalence of coronal tibial bowing in a Western population. This was an observational retrospective cohort study using anteroposterior long leg radiographs collected prior to total knee arthroplasty in our high volume arthroplasty unit. Radiographs were reviewed using a Picture Archiving and Communication System. Using a technique previously described in the literature for assessment of tibial bowing, two lines were drawn, each one third of the length of the tibia. The first line was drawn between the tibial spines and the centre of the proximal third of the tibial medullary canal. The second was drawn from the midpoint of the talar dome to the centre of the distal third of the tibial medullary canal. The angle subtended by these two lines was used to determine the presence of bowing. Bowing was deemed significant if more than two degrees. The position of the apex of the bow determined whether it was medial or lateral. Measurements were conducted by a single observer and 10% of measurements were repeated by the same observer and also by two separate observers to allow calculation of intraclass correlation coefficients (ICCs). A total of 975 radiographs consecutively performed in the calendar years 2015–16 were reviewed, 485 of the left leg and 490 of the right. In total 399 (40.9%) tibiae were deemed to have bowing more than two degrees. 232 (23.8%) tibiae were bowed medially and 167 (17.1%) were bowed laterally. The mean bowing angle was 3.51° (s.d. 1.24°) medially and 3.52° (s.d. 1.33°) laterally. Twenty-three patients in each group (9.9% medial/13.7% lateral) were bowed more than five degrees. The distribution of bowing angles followed a normal distribution, with the maximal angle observed 10.45° medially and 9.74° laterally. An intraobserver ICC of 0.97 and a mean interobserver ICC of 0.77 were calculated, indicating excellent reliability. This is the first study reporting the prevalence of tibial bowing in a Western population. In a significant proportion of our sample, there was divergence between the anatomical and mechanical axes of the tibia. This finding has implications for both the design and implantation of orthopaedic prostheses, particularly in total knee arthroplasty. Further research is necessary to investigate whether prosthetic implantation based on the mechanical axis in bowed tibias results in suboptimal implant placement and adverse clinical outcomes

Fibular hemimelia is associated with equinovalgus deformity of the ankle and hind foot and antero-medial bowing of tibia. A wedge shaped distal epiphysis of the tibia and tight posterolateral soft tissues play an important role in the pathogenesis of ankle valgus and lateral subluxation of foot. Tethering effect of fibular anlage may contribute to the deformities in the tibia and ankle. Lengthening procedures are associated with progression of these deformities. The purpose of this study is to determine whether Exner Osteotomy and Excision of Fibular anlage will correct the valgus deformity of the ankle and antero-medial bowing of tibia. A bending osteotomy through the distal tibial physis as described by Exner and excision of Fibular Anlage was performed in six limbs in five children (4 boys, 1 girl) with fibular hemimelia. Histology of Excised Fibular anlage was studied under light microscopy. The mean age at the time of surgery was twenty two months (range: 8 months to 5 years). The mean follow-up was two years and two months (13 months to 4 years and 8 months). Full Correction of ankle valgus and tibial bowing was achieved in three feet where, a cortical strut graft was used in the open wedge osteotomy. In two feet synthetic bone substitute was used. In these, tibial bowing corrected but slight ankle valgus remained. In one foot where synthetic bone substitute was used and the postoperative compliance with AFO was poor, bowing of tibia improved but ankle valgus recurred. Premature fusion of growth plate did not occur in any of the cases. Histology of fibular anlage showed replacement of bone tissue by mature collagen bundles surrounded by fibroconnective tissue. Exner Osteotomy and Excision of Fibular Anlage in Fibular Hemimelia corrects the ankle valgus and antero-medial bowing of tibia

Varus deformity encompasses a wide spectrum of pathology and merits individualised treatment. In most knees there is loss of articular cartilage or bone medially; this is associated with contractures of posteromedial structures of varying rigidity. In addition, there may be significant elongation of lateral ligamentous structures, and associated extra-articular femoral or tibial bowing or angulation. The principles of correction of varus include (i) a thorough clinical and radiological assessment of the limb before surgery and examination under anesthesia, (ii) appropriate bone cuts to correctly orient prostheses and restore normal alignment of the limb, (iii) equalising medial and lateral balance in flexion and extension by soft tissue releases and concomitant bony procedures and (iv) addressing associated bony defects and extra-articular deformity. Examples of each of these situations will be shown along with the technique deployed. Results of conventional TKA in treating 173 knees with varus deformity exceeding 20o will be presented. Our technique of selective posteromedial release, reduction osteotomy of posteromedial tibial flare, sliding medial condylar osteotomy and bone grafting of medial defects, with preservation of medial collateral ligament integrity will be shown. The method of correcting extra-articular deformity will be depicted. With these techniques, mean tibiofemoral angle of 22.7 degrees varus pre-operatively (range 15–62) was corrected to 5.3 degrees valgus (range 2–9) post-operatively. 86% knees were in 4–10 degrees valgus post-operatively. Recent experience with CAS in treating over 200 patients with deformity exceeding 20 degrees will be presented along with the risk factors leading to malalignment. Correction of severe varus deformity by the techniques reported can successfully restore alignment, painfree motion, and stability without the use of highly constrained implants

The purpose of the study was to evaluate the usefulness of the techniques introduced for correction of the deformities associated with fibular hemimelia. Material. 10 children (6 boys and 4 garils) with affected 11 limbs were analyzed. All presented Achterman-Kalamchi type II fibular hemimelia (absence of the fibula, anterior tibial bowing and hypoplastic foot). Limb length discrepancy ranged from 2 to 9 cm. Only 2 feet had 5 rays, 4 – 4 rays and 5 three rays. In 10 feet talo-calcaneal synostosis was diagnosed intra-operatively. Age at operation ranged from 7 to 23 months (mean 13.2). Follow-up was 4.7 years (1 – 8.5). Technique. Two groups of patients were analyzed. The 1st group consisted of 3 children (3 affected limbs) operated on by partial or complete release of the ankle. Correction of the equinus and valgus deformity was possible by rotation of the talus in the ankle joint in coronal and sagittal plain (the oval shape of talar dome allowed its rotation in the ankle joint). In 2 patients the tibial osteotomy were made as a separate procedure. The 2nd group consisted of 7 children (8 affected limbs) operated on by one-stage technique consisting of (1) trapezoid resection of the tibia for correction of anterior bowing and internal torsion (2) posterior and lateral release of the foot with lengthening of tendo Achilles and peroneals tendons (3) •opening wedge osteotomy through talo-calcaneal synostosis with bone graft taken from the tibia for correction of valgus and equinus deformity (4) skin plasty with subcuteneous flap for wound covering. In this group relationships between talus and tibia were not changed by operation (flat top talus). Results. Both techniques resulted in stabile and properly aligned tibia and hindfoot. Five children were treated later by Ilizarov method at age of 57 months (53 – 80). Other five patients walked independently in orthopaedic or normal shoes. Two of them wait for limb lengthening. The method used in the 2nd group was especially useful for patients with bilateral deformity. The relapse of hindfoot valgus deformity was observed after limb lengthening. Conclusion. One-staged correction of the complex deformity in fibular hemimelia is safe and cost effective. The treated limb was properly prepared for lengthening, wear-bearing in shoes (bilateral cases), orthosis or pros-thesis

Aims

This study aimed to identify the effect of anatomical tibial component (ATC) design on load distribution in the periprosthetic tibial bone of Koreans using finite element analysis (FEA).