Limb length discrepancy

how to mange limb length discrepancy

1. LIMB LENGTH DISCREPANCY Presenter – Dr. Madhukar

2. Limb length discrepancy or anisomelia , Is defined as a condition in which the paired extremity limbs have a noticeably unequal length.

3. Limb length discrepancy in lower extremity is not only a cosmetic concern but also a functional concern. The short leg gait - is awkward - increases energy expenditure because of the excessive vertical rise and fall of pelvis. - and may result in back pain from lon -standing significant discrepncies

4. It is noted that limb-length inequalitis of 0.5 to 2.0 cm are common in the normal, asymptomatic population. Limb-length inequality of more than 2.5 cm are considered to be significant.

5. ETIOLOGY Congenital : - idiopathic unilateral hypo/hyperplasia - hemiarthropathy (Russell-Silver Syndrome) - congenital fibular deficiency (fibular hemimelia ) - congenital tibial deficiency ( tibial hemimelia ) Developmental : - Infections damaging the physis , - Asymetrical paralytic conditions ( eg : poliomyelitis, cerebral palsy ) - Tumors or tumor-like conditions( enchondroma , osteochondroma ) that affect bone growth by stimulating asymetrical growth. Post traumatic : - Malunions and T ruma affecting the physis .

6. Mechanism of Compensation A child with LLD usually compensates better than an adult. Check for specific compensation used the patient to level out the difference in height. – Pronation in the ankle of the longer leg – Plantar flexion in the shorter leg – Knee and hip extension of the shorter or flexion in the longer leg – If the leg is left uncompensated, the anterior and posterior iliac spine on the side of the short leg can be lower which may result in scoliosis. – Increased muscle activity in several muscle groups

7. Effect on spine Low back pain Increased incidence of scoliosis Severity depends on - related severity of LLD - uncompensated or uncorrected - Onset of age

8. Effect on hip Pelvic obliquity A longer leg might be a predisposing factor in Osteoarthritis (OA). Combined with an increased tone in hip abductors caused by elongated distance between origin and insertion and an increased ground reaction force puts the longer at risk.

9. Effect on gait Increased energy Increased force of impact

10. Effect on long bones Greater incidence of stress fractures in tibia, matatarsals and femur of longer leg appear consistent with the greater forces emitted through the longer leg.

11. Evaluation History Examination Imaging - STANDING ORTHORADIOGRAPH - SCANOGRAMA

12. History Congenital or Developmental To determine Casue To determine deformity Onset and mode of deformity

13. Examination Clinical evaluation should include assessment for any rotational and angular deformities, foot height differences, scoliosis, pelvic obliquity and joint mobility and function. In certain paralytic conditions , particularly in spastic diplegia , flexion contracture of the knee and hip make the limb appear shorter than it really is on clinical and radiographic examinations.

14. Wood block test: - with the patient standing, add blocks(known weights) under the short leg until the pelvis is level, then measure the blocks to determine the discrepancy. block testing is considered the best initial screening method. However, asymmetrical pelvic development or pelvic obliquity can cause miscalculation.

15. Leg-length measurement: Apparent length True length

16. Radiographs Commonly used techniques for measuring the limb-length discrepancy Standing orthoradiographs Scanogram Orthoroentgenogram CT Scanogram

17. Orthoradiograph is made on a long cassette that includes hip,knee and ankle on a single exposure. Scanogram uses separate exposures of the hip, knee and ankle, so there is little parrallax errror . But exposure is more in scanogram .

18. Orthoroentgenogram It is a radiographic study used to evaluate anatomic limb-length and calculate limb-length discrepancies. This study utilises a long ruler placed on the film, and three radiographs including bilateral hips, knees and ankles.

19. CT Scanogram These have been praposed as an improvement over standard scanograms because the radiation exposure is less and accuracy is not compramised . On lateral CT Scanograms accurate mesurement can be made of even the limb with flexion deformity.

20. Skeletal age It is an important factor to include when making treatment decisions. GREULICH-PYLE ATLAS is used for determining the skeletal age. A view of left wrist is obtained to estimate skeletal age from the chart. This is however unnecessary for children younger than 5 yrs of age because the skeletal and chronological ages are not significantly different in these children.

21. Techniques for predicting growth remaining Two techniques are widely used to predict the growth and help surgeons determine the timing of limb equalization procedures. Green-Anderson growth-remaining chart. Moseley straight line graph.

22. Green & Anderson chart Proper use of this chart requires the clinician to estimate the percentage of growth inhibition for the patient by taking two interval measurements seperated by at least 3 months. The growth difference the normal and the involved limb is multiplied by 100 , and the result is divided by the growth of normal limb.

23. Moseley straight-line graph Moseley simplified the Green-Anderson chart by mathematically manipulating the original data to allow it to fit on a straight line graph that is visually graphic and easier to apply. This avoids the need of mathematical calculations of growth inhibition and provides a ready prediction of the results of epiphysiodesis , lengthening and shortening.

24. In this 3 measurements are taken every visit Length of normal limb Length of involved limb Skeletal age The difference between the slopes of normal and involved limb is the growth inhibition.

25. Other techniques Menelaus method Paley et al. multiplier method

26. Treatment Treatment of limb-length discrepancy must be tailored to the specific conditions and needs of the individual patients. Treatment plans can be formulated only after a careful evaluation that includes assessment of the chronological and skeletal ages of the patient, the current and the predicted discrepancy in the limb lengths, the predicted adult height, the cause of the discrepancy, the functional status of the joints, and the social and psychological background of the patient and family.

27. Four types of treatment are available for limb-length equalization 1- Shoe rise or prosthetic conversion 2- Epiphyseiodesis of long leg 3- Shortening of long leg(in older patients) 4- lengthening of the short leg

28. Shoe lift For Discrepancies of 1.5cm or less no treatment is necessary. Upto 1cm shoe lift can be provided to wear inside the shoe. For 2 to 4cm difference shoe lift on the outside of the shoe are necessary. For > 5cm shoe rises are unsightly and unstable and may require additional uprights or

29. Epiphysiodesis It is used to describe arrest of growth at a particular physis . Recommended for shortening upto 5cm This can be performed percutaneous and open. Very low morbidity , simple , fast recovary and low complication rate. Disadvantages are Normal limb is operated rather than pathological limb The resulting bony proportions may be cosmetically displeasing after shortening Final height after the procedure may be unacceptably low

30. Phemister technique (JBJS 1933) This technique uses removal of a rectangular block of bone medially and laterally at the level of the physis that is then replaced in a 180 degree rotated position.

31. Epiphyseal stapling (Blount technique)

32. PERCUTANEOUS EPIPHYSIODESIS Described by Mataizeau et al. using transphyseal screws (PETS)

33. TENSION PLATE EPIPHYSIODESIS This is a open technique. This technique is largely reserved for hemiepiphysiodesis in angular corrections. But it can be used for complete epiphysiodesis if implants are used on both sides of the physis . This technique also has the advantage of potential growth resumption with implant removal; however,restoration of normal growth often is unpredictable after implant removal, and careful timing of epiphysiodesis is still important.

34. Most of these plating systems are nonlocking , which allows some degree of screw divergence within the plate as the physis continues to grow. It is likely that growth arrest does not occur until maximal screw divergence is reached. Therefore, it is advisable to place the screws in a divergent fashion at the time of implantation to allow growth arrest to occur as quickly as possible. Usually 4 holed plates are used rather than 2.

35. Canake et al. technique

36. Limb shortening Usually done in skeletally mature patients with discrepancy > 2cm who can accept the loss of stature necessary to equalize the limbs. In Femur – 5-6 cm is the max length that can be removed without seriously affecting muscle function In tibia – 2-3cm Shortening of femur is more preferred due to the high risk of compartment syndrome in tibia due less muscle coverage.

37. Proximal femoral metaphyseal shortening Proximal lateral incision Mark the bone to control rotation Remove the marked segment,leave a spike of medial cortex and lesser trochanter intact to act as butterss . Distal fragment is brought into direct apposition with proximal mad osteosythesis plate is used to achive compression.

38. Distal femoral metaphyseal osteotomy Same as proximal Lateral incision Proximal osteotomy cut is made and then distally For added stability medial spike is preserved Impact two fragments and blade plate is applied under compression.

39. Proximal tibial metaphyseal shortening Lateral incision , resect a portion of fibula at the junction of th proximal and middle thirds. Another anterior incision to expose the proximal tibia. Resect desired amount of bone below tibial tuberosity T plate is applied with after holding two ends of bone under compression. Perform prophylactic fasciotomy .

40. Tibial diaphyseal shortening By broughton,olney and menelaus Longitudinal incision over the anteromedial surface of tibia. Subperiosteal dissection Step-cut osteotomy Through another incision same amount of bone is removed from fibula midshaft . Fix the step-cut osteotomy with two lag screws. Only Indicated in skeletally immature patients.

41. Closed femoral diaphyseal shortening

42. Limb lengthening Device for gradual lengthening – Unilateral fixator – Circular ring fixator ( Ilizarov , Taylor spatial frame ) • Combined internal and external fixation – (Lengthening over IM Nailing) • Totally implantable lengthening device – Albizzia nail – ISKD( intramedullary skeletal kinetic device)

43. Transiliac lengthening By Mills and Hall Anterior ilioinguinal approach Perform Osteotomy from sciatic notch to anterior inferior iliac spine Take a full thickness trapezoid shaped block of iliac crest Wedge this iliac graft into the distraction site and hold it with two large, threaded Steinmann pins.

44. Tibia Lengthening BY DEBASTIANI ET AL. Uses orthofix lengthening devices

45. This technique uses the principle of lengthening by callotasis ( or low-energy corticotomy followed by gradual distraction of the bone fragments with a mechanical apparatus). Distraction should begin after a brief latent period of 1 – 3 weeks to allow for early callus formation. The rate of distraction should be approx. 1mm per day divided over four 0.25mm increments.

46. Ilizarov method Principle: – It is based on the principle of distraction osteogenesis . – A bone that has been cut during surgery are gradually pulled apart ( distraction) – Leads to new bone formation ( osteogenesis ) at the site of lengthening

47. Advantage of ilizarov over monolateral fixators is the ability to gradually correct angular or rotational deformities by adjusting the configuration of the frame witout use of anesthesia. 3-7 days of latency period allows development of callus at the site of corticotomy which is then followed by distraction period. After lengthening, the limb is still in external fixator until adequate consolidation of the new bone has occured . Typically, consolidation period is approximately twice the distraction period.

48. Taylor spatial frame Used for deformity correction and lengthening. A basic system with two rings and six telescopic rods with special link joints. This frame also uses the slow correction principles of ilizarov but adds a six axis deformity analysis incorporated into a computer program. This program has show a steep learning curve has high cost.

49. Femur lengthening By DEBASTIANI ET AL. Perform a corticotomy just distal to the ilio-psoas insertion. Incise the anterior thigh skin longitudinally between sartorius and tensor fascia lata muscle and then incise the periosteum longitudinally and elevate it. Now drill a series of 4.8mm unicortical holes in anterior 2/3 rd circumfarence of femur of 1cm depth not entering the medullary cavity. Use a thin osteotome to connect the holes and the flex the femur at the corticotomy to crack the posterior cortex to complete the corticotomy . Orthofix lengthening device is then applied ( use six pins for femur to gain stability and to resist varus deviation )

50. Femoral lengthening over intramedullary nail (ISKD) By COLE, PALEY AND DAHIL ISKD - Intramedullary Skeletal Kinetic Distractor

51. Complications Pin track infections Muscular problems Joint problems Neurovascular problems Bone problems

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