Femoral Angle of Inclination• Angle within the frontal plane between the femoral neck

and the medial side of the femoral shaft

– Average adult measurement of 125 degrees

– Newborns born with 140-150 degree angle which reduces to approximately 125 degrees with onset of standing/walking

Determines :-The effectiveness of hip ABD musclesThe length of the limbThe forces acting on the hip joint and femoral neck

Angle of Inclination• Coxa Vara – A of I markedly less than 125 degrees• Coxa Valga – A of I markedly greater than 125 degrees

Coxa Vara•If the angle of inclination is less than 125 degrees it is termed coxa vara.

This:1. shortens the limb;

2. decreases the effectiveness of the abductors;

3. increases the load on the femoral neck;

4. reduces the load on the femoral head.

•If the angle of inclination is greater than 125 degrees it is termed coxa valga.

Coxa Valga

This:1. lengthens the limb;2. mimics contracture of the hip

abductors;3. reduces the load on the

femoral neck;4. increases the load on the

femoral head.

Symptoms of Coxa Vara-:

• stiffness,• pain, •difference in leg length(shortening) ,resulting in a limp and difficulty walking. •Unilateral involvement with an associated relative limb-length discrepancy and Trendelenburg limp may be noted. This discrepancy in limb lengths usually is mild, ranging from 1.5 to 4.0 cm•Waddling gait in bilateral cases•weak abductors, •a prominent greater trochanter,• decreased abduction •A decrease in internal rotation also is often noted, caused by decreased femoral anteversion or true retroversion associated with this condition.

Diagnosis :- Coxa Vara can be diagnosed by X-Ray.

Coxa Valga (L) v. Coxa Vara

Coxa Vara typically falls into one of three categories:

congenital,

developmental,

or acquired.

Congenital Coxa Vara (CCV) is present at birth, and believed to be the result of either embryonic abnormalities or possibly the result of certain intrauterine conditions or mechanical stresses that could affect the way in which the hip forms.

The developmental form of Coxa Vara presents itself during early childhood and seems to follow a progressive pattern that continues as the child develops.

Acquired forms of the condition can also come as the result of an injury such as a fracture or other traumatic event to the hip.

The Types of Coxa Vara

Surgical Therapy:-The goals of surgical intervention are as follows:

•Correction of the neck shaft angle to a more physiologic angle•Correction of femoral anteversion (or retroversion) to more normal values•Ossification and healing of the defective inferomedial femoral neck fragment•Reconstitution of the abductor mechanism through replacement of its normal length-tension relationship

The treatment of choice for CCV is subtrochanteric or intertrochanteric osteotomies( valgus osteotomies)

Femoral Torsion Angle(angle of anteversion)Torsion angle – relative rotation (twist) that exists between the shaft and neck

of the femur. The angle of the femoral neck in the transverse plane is termed the angle of anteversion.

Normal Anteversion: Normally the femoral neck is rotated anteriorly 12 to 14 degrees with respect to the femur. Increases the MA of the gluteus maximus – making it a more effective hip external rotator

• Excessive anteversion: beyond 14 degrees causes the head of the femur become uncovered. – tends to dislocate, unstable hip

Retroversion:If the angle of anteversion is reversed so that it moves posteriorly, it is termed retroversion. TA significantly less than 15 degrees

Normal Anteversion – 10-15 degrees allows optimal alignment and joint congruency

Normally the femoral neck is rotated anteriorly 12 to 14 degrees with respect to the femur.

Average adult measurement of 10-15 degrees of anterior rotation (Anteversion) of femoral head

Newborn TA typically 30 degrees of anteversion; which reduces to 10-15 degrees by 6 years of age

Excessive Anteversion :-

TA significantly greater than 15 degrees causes the head of the femur become uncovered.

Often associated with congenital dislocation in the infant; marked joint incongruence; and increased degenerative wear

•In order to keep the head of the femur within the acetabulum a person must internally rotate the femur.

So ,Compensated excessive anteversion may result in “toeing-in” gait pattern (“pigeon toed”)

Femoral Torsion Angle (cont.)

Excessive Femoral Anteversion

Retroversion :–

•If the angle of anteversion is reversed so that it moves posteriorly, it is termed retroversion.

• TA significantly less than 15 degrees (i.e. 5 degrees of anteversion

•This condition causes the person to externally rotate the femur and produces a toe out gait (duck feet).

• Less common than excessive anteversion

Femoral Torsion Angle (cont.)

DEVELOPMENTAL COXA VARA Eric Sandefur, D.O., Pediatric Orthopaedic Surgery William G. Mackenzie, M.D., Attending Pediatric Orthopaedic Surgeon August 2, 1995 CLINICAL CASE PRESENTATION ORTHOPAEDIC DEPARTMENT THE ALFRED I. DUPONT INSTITUTE WILMINGTON, DELAWARE DEFINITION : •also known as cervical or infantile coxa vara •represents coxa vara not present at birth but rather developing in early childhood •coxa vara is defined as any decrease in the femoral neck-shaft angle less than 120 - 135 degrees

INCIDENCE : •relatively uncommon, occurring approximately 1 in 25,000 live births •occurrence is essentially equal in males to females and left to right •bilateral involvement is note in 30 - 50% of patients •recent reports have shown increase incidence in black population compared with whites •reports have also shown a familial pattern with an autosomal dominant form of transmission

ETIOLOGY : •currently remains unknown •the most popular theory, proposed by Dylkkanes in 1960, states that the deformity is caused by a defect of enchondral ossification of the femoral neck. Weightbearing causes shearing stresses which result in fatigue of the dystrophic one and progressive varus deformity results •other proposed theories include: •metabolic abnormalities cause a deficiency or delay in the ossification process •mechanical abnormalities may occur during development and early ambulation •partial vascular insult to the inferior aspect of the femoral neck •developmental abnormality which causes faulty cartilage formation and maturation •histologic studies have shown that there are abnormalities in both cartilage production and metaphyseal bone formation. These findings are similar to those found in the proximal tibia in patients with Blount's disease.

CLINICAL PRESENTATION: •most commonly seen between when the child begins to ambulate and age six •most common complaint is a progressive gait abnormality •in unilateral involvement this is due to both abductor muscle weakness and limb length inequality •patients with bilateral involvement have a waddling gait and increased lumbar lordosis (similar to that seen in bilateral DDH) PHYSICAL EXAM: •prominent and elevated greater trochanter

•positive Trendelenburg test •limb-length inequality (usually less that 2.5 cm) •decreased ROM with restrictions noted with abduction and internal rotation RADIOGRAPHIC FINDINGS:

femoral-neck shaft angle below 90 degrees •more vertical position of the epiphyseal plate with Hilgenreiner's-epiphyseal angle greater than 40 degrees (normal is less than 25 degrees) •triangular metaphyseal fragment in inferior femoral neck surrounded by

inverted Y (sine qua non) TREATMENT : aimed at the prevention of the secondary deformities caused by the disease's natural history on the proximal femur

main objectives of surgical treatment include: •correction of varus angulation •changing of the loading characteristics from shear to compression of the femoral neck •restoring proper length of abductors muscles •resolution of limb-length inequalities current criteria for surgical intervention include one or more of the following: •femoral neck-shaft angle less than 90 - 100 degrees •Hilgenreiner's-epiphyseal angle greater than 45 - 60 degrees •documented decrease in the femoral neck-shaft angle •Trendelenburg gait •currently, the most effective surgical treatment is a valgus producing proximal femoral osteotomy (subtrochanteric vs intertrochanteric procedures have similar results)

proper surgical treatment also includes: •adductor tenotomy which allows for less forceful correction and improved stability •proximal femoral shortening osteotomy if necessary to help relieve excessive femoral head pressure when the valgus angle is restored •stable internal fixation and hip spica cast if needed •goal of surgical treatment is to produce an overcorrection of valgus angle to greater than 150 - 160 degrees, as well as, correction of epiphyseal angle to less than 30 degrees •The timing of surgery remains controversial. Several authors recommend delay surgery until 5 6 years of age. Others state that surgery may be performed after 18 months if the above criteria are met.

COMPLICATIONS: •Recurrence of proximal femoral varus deformity-many feel that this is due to undercorrection at surgery while others feel that it is due to failure to place the osteocartilaginous defect into a compressive mode •Premature physeal closure-the incidence may be as high as 89% and has not been found to be related to physeal injury at the time of surgery •Greater trochanteric overgrowth-associated with premature capital femoral physeal closure and is commonly treated by greater trochanter transfer or epiphysiodesis •Acetabular dysplasia-found to be increase in patients with premature physeal closure and inpatients who have had an undercorrection of the neck-shaft angle less than 140 degrees •other complications have included pseudarthrosis, avascular necrosis, leg-length discrepancy, and degenerative arthritis