Principle of Deformity Correction in lower Limb

A brief summary about the priniciple of deformity correction in paediatrics and adults with the effects of deformity, etiology, physiological deformity, clinical and radiological assessment, measurements of various lines and angles, various terminologies, preoperative templating, acute and gradual correction , osteotomy principle and techniques, methods of fixation and stabilization.

1. Principles of Deformity Correction- Lower Limb Presenter K aushal Raj K afle Moderator Dr Sharad Adhikari

2. Contents Introduction Etiology Clinical a ssessment Radiological assessment Preoperative planning Management Principles of osteotomy Methods of fixation and complications

3. Deformity Departure from normal bone or joint anatomy A structural deviation from the normal shape, size or alignment resulting in disfigurement Significant when it compromises the patients function

4. Axes of Deformity X Y Z plane 6 degree of freedom Angulation, translation and rotation Length – axial translation

5. Consequences Primary Change in mechanical axis of limb on weight bearing Affects individual joint orientation Secondary Compensation by other joint by changing their motion of arc Joint contact pressure affected > Unphysiological load > Degeneration Muscle fatigue and pain in attempt to maintain unphysiological joint position

6. Compensation at adjacent bones Active Physes Anatomic correction unmasks the secondary deformity Correction till limb aligns clinically puts joint in obliquity to mechanical axis Anatomic normal state requires two osteotomies at two bones Significant Morbidity

7. Difference in Upper limb and Lower Limb Affects the arc of motion Disturbs forearm functional unit Length asymmetry well tolerated Cosmetically better tolerated Degeneration not much of problem

8. Etiology Paediatric Congenital Adolescent Developmental Physeal arrest Adult Trauma Elderly Metabolic Long term sequalae of malalignment

9. Causes Congenital Fibular hemimelia Proximal Femoral focal deficiency Post Traumatic Malunion AVN Non union with malalignment Physeal arrest Developmental Blounts disease Diaphyseal aclasia Metabolic Rickets Paget’s disease Infection Meningococcal septicemia with physeal arrest Osteomyelitis Tumor Degenerative Genu Varum

10. Approach to Deformity Determine if it is abnormal? Define its characteristics. Determine if it needs treatment ? Generate treatment plan.

11. Physiological Deformity

12. Clinical Assessment History Need for consultation : cosmetic VS functional Functional limitation and effect on activity of daily l iving Pain and its characters Other Conditions: Dysplasias , Metabolic, Non skeletal condition More than one deformity Progression of deformity

13. Examination Bony deformity Angular, rotational, translational and axial Associated condition Joint contracture Soft tissue condition Skin condition Complete neurovascular assessment

14. Examination Inspection Coronal ( varus or valgus) Sagittal (apex anterior or posterior ) Compensation for a leg length discrepancy Length assessment Wooden Block Length measurement Galeazzi test

15. Examination Rotational Deformity Craig test Thigh Foot angle Transmalleolar Axis Heel bissector line Foot progression angle

16. Radiographic Assessment Aim Plane (Frontal/Sagittal/Coronal) Direction ( Varus /Valgus; Anterior/Posterior) Bone and Joint (Tibia/Femur; Hip/Knee/Ankle) Segment of Bone (Epiphysis/Metaphysis/Diaphysis) Apex Magnitude

17. Standardized X Ray AP and lateral views 100% magnification Including hip knee and ankle Standing Patella facing forward (Between Femoral condyles) LLD corrected with blocks Contralateral Limb as Reference

18. Scanograms CT Topograms Measures overall leg length and tibial and femoral lengths. CT Torsional abnormalities with axial CT scans . 3D templating and printing Accurate planning

19. Axis of long bone Mechanical Axis (MA) Line Joining the centre of joints proximal and distal to the the bone Anatomical Axis (AA) Line joining the multiple centre points of transverse diameter along the length Tibia : MA = AA Femur MA not equal AA

20. Mechanical axis Always straight whether frontal or sagittal plane. Measures varus and valgus alignment

21. Anatomical Axis Normal bone-single straight line. Deformed bone with angulation each bony segment has its own anatomic axis.

22. MAD / Malalignment Loss of colinearity between hip, knee and ankle Distance between MA and centre of knee Medial : Varus Lateral : valgus Deformity around Joints with large ROM are well tolerated.

23. Joint Orientation line Relation of joint axis to the AA and MA Both in frontal and sagittal plane. Knee JOL 3 o valgus JCLA Ankle JOL parallel to floor to 8 o valgus

24. JOL in saggital plane Posterior slope of the tibial plateau ( normal 7–9 o ) Anterior slope of the tibial plafond (normal 7–10 o ) Tibia recurvatum / procurvatum

25. Joint Orientation Angle Relation between anatomical or mechanical axis with the joint orientation lines LDFA n 2 o Valgus with MA 7 o Valgus with AA MPTA 1-3 o Varus with MA/AA LDTA

26. Centre of Apex of Rotation (CORA) Diaphysis : Intersection of the proximal axis and distal axis of a deformed bone Metaphyseal or Juxtaarticular : Intersection of the Line perpendicular to JOL and middiaphyseal line of deformed bone Surgeon has no control over CORA

27. CORA Multiapical Deformity : More than one CORA CORA and Apex of deformity do not coincide : Additional Translational deformity CORA in both frontal and sagittal plane : Oblique deformity

28. Bisector Line Line that passes through the CORA and bisects the angle between proximal and distal half of deformity Angular correction around bissector realigns of anatomic and mechanical axes without introducing iatrogenic deformity

29. Angulation Correction Axis (ACA) Axis of rotation around which correction takes place Can be different from CORA or Osteotomy site Surgeon has some control over ACA and osteotomy site

30. Preop Planning/ Templating Pencil and Scissors Dedicated softwares mediCAD AO Osteotomy software TraumaCad Digital Orthopedic Templating Bone Ninja

31. Steps in Planning Correction Measuring all parameters in systematic manner to determine the site and amount of CORA

32. Final Outcome Relative position of CORA, ACA and Osteotomy site decides the final position of bone segments.

33. Management Goal Improve the function of limb and patient Surgical Aim Accurate Correction Early Union Maintenance of Joint ROM Early Weight bearing Low incidence of post op complication

34. Corrective Surgery Balancing anatomical ‘ normality’ with the anticipated gain in function. ‘ Anatomical’ correction, desirable, is not always necessary.

35. Factors affecting Correction Acute Gradual Age Well established deformity Skeletally immature patient Amount Less than 15-20 degree Greater deformity Site Neurovascular structure on concave side Soft tissue Poor vascularity, poor elasticity Scarring and tethering of vessels Compromised healing, infection and necrosis Associated LLD Recommended General Medical Condition Diabetes, use of steriod and NSAIDs, smoker,

36. Correction : Acute All deformity corrected at once : immediate satisfaction Quicker return to activity Accuracy of correction No further adjustments Soft tissue and NV under tension Translation component may hinder fixation Only limited amount of lengthening

37. Correction : Gradual Gradual Allows adjustments Allows certain amount of axial loading Bone resections can be avoided Simultaneous limb lengthening is possible along with correction of angular and rotational deformity Cumbersome fixation devices Frequent Clinic Visits Prolonged rehabilitation

38. Growth Modulation Hemiphyseal stappling /Percutaneous screw across physis Symmetric Angular deformity Advantage Low surgical morbidity Reversibilty of growth deceleration after staple removal Disadvantage Uncertain nature Recurrence Continued angular growth

39. Osteotomy 1 . Angulation-only osteotomies Opening wedge Closing wedge 2. Angulation with translation osteotomies. Circular cut (dome) Oblique cut

40. Principles of osteotomy Uniapical deformity with CORA, ACA and Osteotomy in same plane Proximal and distal bone axis become collinear and are realigned with no translation

41. ACA is through CORA, Osteotomy at different level Axis will realign with angulation and translation

42. Osteotomy and ACA is away from CORA Secondary translational deformity will occur.

43. CORA and Apex of deformity at different level

44. CORA lies outside the boundaries of the involved bone, a multi-apical deformity is present Deformity more akin to a curve Requires multiple osteotomies.

45. Dome Osteotomy More cylindrical than spherical Osteotomy site does not pass through the mutual CORA correction axis Obligatory translation Principle of Wedge Osteotomy holds true for Dome osteotomy

46. Axis of correction Convex border: Opening Dome Concave Border: Closing dome At the axis : Neutral Dome

47. Internal Fixation Plates and screws Percutaenous pins Acute correction Rigid fixation Versatile for peri -articular deformities Direct visualisation Extensive soft tissue dissection Limitation of weight bearing Inability to correct shortening

48. Internal Fixation Intramedullary devices Diaphyseal deformity Metaphyseal diaphyseal deformity Osteopenic bone

49. External Fixation Minimal soft tissue dissection Minimal infection Post op adjustment Axial translation, angular deformity correction Longer healing time Slower mobilization Potentially complex surgery Poor patient acceptance and compliance Illizarov ring f ixators Garches clamp Taylor spatial frames

50. Complications General Infection , thromboembolism Undercorrection / Overcorrection Nerve tension Acute correction avoid >20 o Compartment Syndrome Non Union

51. Summary Deformity and its correction is a fundamental part of orthopedic surgery. A balanced and matured approach is needed as every deformity does not require correction. Personality of Deformity must be well understood before planning any corrective surgery. Relative position of CORA, ACA and Osteotomy site determines the final outcome. Though exacting procedures, use of various planning tools, osteotomy techniques with various fixation methods has made deformity correction more straightforward .

52. References Apley and Solomon's System of Orthopaedics and Trauma, 10e Tachdjian's Pediatric Orthopaedics Principle of deformity correction, Butcher and Atkins (Current Orthopedics) Relevant online articles.

53. Thank you Next presentation Coxa Vara by Dr Aakash Prabhakar