Plain Radiography

Teleoroentgenography.

Teleoroentgenography is the simplest whole-leg radiographic technique for the assessment of leg length inequality. A radiograph of the entire lower extremity is obtained with the patient supine on the radiography table, with a long film and radiographic ruler beneath the patient. This technique is also the most susceptible to magnification error because a single exposure is made from a midpoint on the patient’s lower extremities ( Fig. 24-7 ). It is useful, however, if the patient is unlikely or unwilling to hold still for multiple-exposure techniques.

Teleoroentgenography. A long film and a ruler are placed under the patient, and a single exposure is made, centered over the limbs.

Orthoroentgenography.

Orthoroentgenography is a radiographic technique described by Green and colleagues in 1946. The purpose is to minimize measurement error resulting from magnification by making three separate exposures of the lower extremities centered over the hips, knees, and ankles ( Fig. 24-8 ). One long film with a radiographic ruler is obtained, similar to in the teleoroentgenogram. In patients with significant leg length inequality, separate exposures for each leg may be made, with the x-ray beam centered over each joint. It is important that the patient not move between exposures (Green and colleagues ensured this immobility by strapping the patient to the table after positioning) and that the limbs be aligned neutrally. Saleh and Milne described the use of this technique in a weight-bearing position so that angular deformities, mechanical axis deviations, and limb length can be assessed simultaneously in that position. Weight bearing is not important to the accurate measurement of leg length inequality.

Orthoroentgenography. A long film and a ruler are placed under the patient. Three (or six) exposures are made at the hip, knee, and ankle level, without moving the patient or the film.

Scanography.

The term scanography arose from an early technique called slit scanography, but it has come to be used for a technique similar to orthoroentgenography. Scanography differs from orthoroentgenography in that, in addition to movement of the x-ray tube over the patient for three exposures, the film is moved under the patient ( Fig. 24-9 ). This approach reduces the size of the film required and makes storage and handling easier. As in orthoroentgenography, the patient must remain motionless during the exposures. The entire length of the bone is not available on film, thus negating this technique as a screening tool to assess the cause of leg length inequality.

Scanography. A, A 14 × 17-inch film and a ruler are placed under the patient. Three (or six) exposures are made, centered over the hips, knees, and ankles. The film is advanced under the joint to be radiographed and is exposed sequentially. B, Scanogram. A smaller film is used than in orthoroentgenography, thus making storage and handling easier. Only a portion of the bone segment is visible on the radiograph.

Computed Radiography

An alternative to conventional radiography is low-dose computed radiography. The radiation dosage exposure with this method is significantly reduced (as little as 1% of the exposure with conventional radiography for orthoroentgenograms), and the accuracy is comparable to that of conventional radiography.

Computed Tomography

CT has become popular for the assessment of leg length inequality. ^¶ Advantages include lower radiation exposure even when the entire limb is exposed, greater accuracy, less susceptibility to error if the patient is poorly positioned, and the ability to accommodate positioning difficulties secondary to joint contractures or the presence of external fixators ( Fig. 24-10 ). This technique is specifically indicated when the patient has a knee flexion contracture or is in a circular external fixator because the accuracy is greater than that of conventional orthoroentgenography under these conditions. The radiology technicians responsible for obtaining CT scanograms must position the patient’s limbs symmetrically or should at least ascertain that a given positioning difficulty will not interfere with accurate measurement. For example, hip or knee flexion contractures are well accommodated by CT when measurements of segment length are taken from the lateral projection, but only if the limb is in a neutral position with respect to abduction or adduction at the hip or there is no asymmetric frontal plane angular deformity.

Computed tomography (CT) scanography. A, CT scanography requires less radiation exposure and less time to acquire, and it is susceptible to fewer magnification, positioning, and movement errors. B, The technique is particularly useful when positioning is difficult or must be nonstandard, such as when the patient is in a circular external fixator.

¶ References .

Ultrasonography

Ultrasonography has been used for the assessment of leg length inequality. Junk and colleagues found that this technique was more accurate than clinical assessment alone, and Terjesen and associates found the accuracy to be within 2 mm of standard radiographic techniques. However, special jigs must be constructed, and the patient must not move during the examination. The main advantage of this technique is that exposure to ionizing radiation is not required. We have no experience with this technique of assessing leg length inequality.

Alterations of Growth

In 1862, both Hueter and Volkmann noted that compressive forces in bone resulted in a slowing of growth and that tension increased bone growth and the formation of osseous tissue (the Hueter-Volkmann principle). Wolff disputed this, believing that both compression and tension resulted in bone growth stimulation. Haas in 1945 and Gelbke in 1951 demonstrated that wire loops placed around the distal femur in dogs impeded longitudinal bone growth. Haas also noted that pins placed across the physis could restrict longitudinal growth. Gelbke stated that the controversy regarding the influences of compression and tension on longitudinal growth arose from a failure to distinguish between growing and mature bone and that bone tissue formation and bone growth were considered identical processes. When he placed loose and tight wire loops around the distal femurs of growing dogs, Gelbke found that longitudinal growth continued for several months, until pressure developed across the physis; the physis then narrowed radiographically and histologically, and growth inhibition followed. Gelbke also noted that these changes were reversible if the wires were cut after physeal narrowing and growth inhibition had occurred. He also attempted to produce traction on an apophyseal physis with wire loops, with less success. He concluded that the effect of tension on the physis does not increase enchondral bone growth and appears to have the same effect as compression.

Functional Physeal Anatomy

The physis is divided into horizontal zones termed germinal, proliferative, hypertrophic, and provisional calcification ( Fig. 24-11 ). The entire process of growth in this fashion—longitudinal growth by the cartilaginous “plate,” followed by ossification of the cartilaginous precursor—is known as enchondral ossification. Horizontal or peripheral growth of the physis occurs as well, in the specialized groove of Ranvier. The control of longitudinal growth and the mechanisms of cartilage cell hypertrophy, calcification, and ossification are still not thoroughly understood and are subject to many central and local hormonal and mechanical influences. The most widely recognized central hormonal regulator of physeal growth is growth hormone (GH). GH deficiency is associated with proportionate short stature, and excess GH secretion in the skeletally immature results in gigantism. GH action on physes is mediated by insulin-like growth factors produced in both the liver and physeal chondrocytes. Another important class of polypeptides (at least 10 classes have been identified) influencing normal physeal activity consists of the fibroblast growth factors, which have a mitogenic influence on physeal chondrocytes. A genetic defect in the fibroblast growth factor-3 receptor is responsible for achondroplasia.

Scheme of organization of the growth plate, or physis. The histologically identifiable layers include the resting or germinal layer and the proliferative, hypertrophic, and provisional calcification layers progressing from epiphysis to metaphysis.

Longitudinal growth of the epiphyses themselves is usually not taken into account when estimating the longitudinal growth of a particular long bone. Clinical and radiographic anthromorphometric measurements of the long bones during growth are usually made from the ends of the epiphysis; the contributions to longitudinal growth of the physes at both ends of the long bones of the upper and lower limb segments are known and are limited to the physes themselves. Thus, as Moseley has pointed out, growth data on the length of the leg and its femoral and tibial segments pertain to the entire length of the bone from epiphysis to epiphysis, but calculations regarding final length by virtue of growth from the physes ignore the increase in length provided by the epiphysis.

In long bones with physes at each end, the contribution of each physis to the longitudinal growth of the bone is typically asymmetric (see Fig. 1-9 ). Digby studied the contribution of longitudinal growth by assessing growth arrest lines in anatomic specimens. Anderson and colleagues estimated the contributions to longitudinal growth of the distal femur and proximal tibia by assessing sharply delineated growth arrest lines on consecutive radiographs in a semilongitudinal study of 206 boys and girls. These investigators found that 71% of femoral growth occurred distally, and 57% of tibial growth occurred proximally.

The timing of the appearance of the secondary centers of ossification, which make the physis radiographically identifiable, also varies by location and, to some extent, by individual. Finally, the timing of closure with cessation of longitudinal growth in individual physes also varies by location and individual (see Figs. 1-5 and 1-7 for these approximations).

Anderson-Green-Messner Growth-Remaining Charts

Anderson, Green, and Messner published two articles that provide important information on the longitudinal growth of the femur and tibia and an estimation of growth remaining that can be used to time epiphysiodesis or stapling. The first article, published in 1963, examined longitudinal growth data obtained in 100 children (50 boys and 50 girls) who were assessed at least once a year in the 8 years before their growth terminated. Fifty-one of the children were normal (25 girls and 26 boys), and 49 had poliomyelitis affecting only one lower extremity; the data from the normal legs of these 49 children were incorporated into the data from the normal children. Orthoroentgenograms (measuring the length of the femur and tibia, including each epiphysis), hand and wrist films for skeletal age (using Greulich and Pyle’s atlas ), total body size, and other variables were measured at each visit. Visits were scheduled close to the subjects’ birthdays, and measurements (including skeletal age) were recorded against chronologic age ( Table 24-1 ).

A number of interesting findings emerged from this study. The annual rate of overall growth (stature) rapidly decreased from birth to age 6 years and was stable from ages 6 through 9 years (average stature increment, 5.7 ± 0.93 cm). Femoral length increased at an average annual rate of 2.0 ± 0.27 cm, and tibial length increased at an average annual rate of 1.6 ± 0.23 cm. A pubertal growth spurt typically occurred sometime after age 9 years (and usually reached a maximum between 10 and 12 years of age in girls and between 12 and 14 years of age in boys). This growth spurt was followed by a final 4-year period of rapid decline in the rate of growth until cessation of growth ( Fig. 24-12 ). When average figures for stature and femoral or tibial length changes per year of chronologic growth were computed, the amplitude of the peak was blunted because the age at which the growth spurt occurred varied from one child to the next. In general, growth continued for 2 years after the adolescent growth spurt, irrespective of the age at which it occurred. As a consequence, although tables and graphs based on chronologic age are useful in younger children, because of this variation in the onset of the pubertal growth spurt these tables and graphs are not as valuable in children with 5 to 6 years of growth remaining.

Average yearly rates of growth (femur, tibia, and total stature) as determined by Anderson and colleagues, from the data presented in Table 24-1 . A, Pattern of growth in a boy from age 1 to 18 years. Note the decreasing rate of growth in stature and in femur, tibia, and trunk length during the first decade. In the second decade, there is a definite short period of accelerated growth—the adolescent growth spurt. This general pattern of growth is similar in all children. B, Average yearly rates of growth derived from completely longitudinal series in 50 girls ( left ) and 50 boys ( right ).

Anderson and colleagues used skeletal age, as published by Greulich and Pyle, but noted that assessments from the elbow, hip, knee, and foot can also be used, as well as physical maturation parameters (such as Tanner’s stages of development; see Chapter 1 ). These authors found that when skeletal age was used as the basis for interval changes, the mean values for growth remaining were essentially the same as when chronologic age was used, but the recorded variation around the mean was appreciably less when skeletal age was used. Thus more precise estimates of future growth in an individual child could be made by using skeletal rather than chronologic age, particularly in children whose level of maturation was consistently advanced or retarded 2 years or more compared with their chronologic age.

The method that Anderson and associates used to develop their growth-remaining charts was to interpolate the length of each of the 100 femora and tibiae at specific, equally spaced skeletal ages (10 years 3 months, 11 years 3 months, and so on). The increments of growth between these consecutive skeletal ages were derived. The growth of the entire femur and tibia was then related to the growth at the specific physes by using figures for the proportional contribution of growth obtained from the semilongitudinal study of sharply delineated growth arrest lines on consecutive radiographs (71% of femoral growth occurred distally, and 57% of tibial growth occurred proximally). These results were then used to compile the growth-remaining charts for boys and girls in the distal femur and proximal tibia ( Fig. 24-13 ). An example of the variations encountered was provided by Anderson and colleagues themselves, who noted that the 50th percentile growth remaining at the distal femur for a girl of skeletal age 10 years 3 months was 4.1 cm, whereas the extremes of growth that occurred at that age were actually from 2.2 to 7.2 cm; 80% of these girls were noted to grow between 3.3 and 5.0 cm.

Growth-remaining charts for the distal femur and proximal tibia for girls ( A ) and boys ( B ), as determined by Anderson and colleagues. These charts are based on the growth data presented in Table 24-1 and an estimate of the contribution to growth of the distal femur (70%) and the proximal tibia (56%) to the total length of the respective bone. Data are presented relative to skeletal age from age 8 years to skeletal maturity. Skeletal age was determined from hand and wrist films compared with Greulich and Pyle’s atlas.

Anderson and associates described how the growth-remaining charts were to be used in their 1963 article. Green and Anderson had presented less complete versions in 1947 and 1957. The first consideration is the growth of the side not operated on. These investigators noted that the rate of growth inhibition in poliomyelitis is not constant over the entire period of growth and recommended determining the rate of growth in the 2 to 3 years before treatment by epiphysiodesis. In addition, if the physis of the affected leg is not growing at all, no correction should be expected, only prevention of further leg length inequality. The second consideration is the child’s relative maturity, the importance of which cannot be overemphasized. These investigators concluded that forming a total picture of each child is important, and they did not attempt to reduce the prediction of results to a precise, mathematical formula.

The second article by Anderson and colleagues, published in 1964, provided data on the length of the femur and tibia from a completely longitudinal study of 67 boys and 67 girls derived from radiographs taken on their birthdays from 1 to 18 years of age. The radiographs were teleoroentgenograms in younger children and orthoroentgenograms in older children. The authors used “appropriate” conversion factors on these 6-foot films to arrive at true femoral and tibial lengths. Recorded femoral length was “from the proximal articulating surface of the capital epiphysis to the most distal point on the lateral condyle,” and recorded tibial length was “from the mid-point of a line drawn across the proximal condyles to the mid-point of the distal articulating surface.” The data ( Tables 24-2 and 24-3 ) were used to generate length of femur and tibia graphs for boys and girls based on their chronologic ages ( Fig. 24-14 ). The difficulty of reconciling maturation and relative height can be seen in the authors’ example ( Fig. 24-15 ): longitudinal follow-up of a boy with hemihypertrophy showed a “dip” from 1 standard deviation above the norm to the norm during a period of presumed “delayed” maturation. Thus assessment only during adolescence would give a false picture of the percentile length of the individual’s femur and tibia and lead to an underestimation of the amount of growth remaining during that time.

Average total length of the femur and tibia (including epiphysis) with a 1 and 2 standard deviation range in girls ( A ) and boys ( B ), based on chronologic age.

(Courtesy Drs. M. Anderson, M.B. Messner, and W.T. Green.)

Example of change in percentile length of both femur and tibia (including epiphyses) of a patient followed for hemihypertrophy by Anderson and colleagues. As they noted, if only one examination had been performed when the patient was an adolescent, there would have been a false impression of 50th percentile length, resulting in an underestimation of the ultimate discrepancy. This example points to the need for and value of longitudinal follow-up to gain an overall impression of the maturation and relative size of each patient.

(Redrawn from Anderson M, Messner MB, Green WT: Distribution of lengths of the normal femur and tibia in children from one to eighteen years of age, J Bone Joint Surg Am 46:1200, 1964.)

Menelaus Method

Menelaus reported on his experience with the White method (reported by White and Stubbins in 1944) in 1966 and reaffirmed this experience in 1981. White had originally suggested that the distal femur grew ⅜ inch and the proximal tibia grew ¼ inch per year, with growth stopping at age 17 in boys and at age 16 in girls. Menelaus modified that assumption of growth cessation to age 16 for boys and age 14 for girls ( Fig. 24-16 ). He reported the results at skeletal maturity in 44 children who had undergone 53 epiphysiodeses using the Phemister technique and immobilization in plaster for 6 weeks. At skeletal maturity, 52% of the patients had leg length inequality within ¼ inch of the calculated discrepancy and 41% within ¾ inch of the calculated discrepancy; 7% had a residual discrepancy of more than ¾ inch. Menelaus stated that 89.6% of Green and Anderson’s patients were within ½ inch of the calculated discrepancy, compared with 80% of Menelaus’ patients.

Approximate percentage contribution to total leg length increase and average growth per skeletal year of maturation (in millimeters and inches) of the distal femoral and proximal tibial physes.

Moseley Straight-Line Graph

Moseley in 1977 described a straight-line graph method for calculating the ultimate discrepancy in a skeletally immature child and determining the timing of long-leg epiphysiodesis to correct leg length inequality. His method is discussed further in other publications. The graph was constructed based on a mathematical reanalysis of the chronologic growth data on the length of the femur and tibia in normal boys and girls that were published by Anderson and colleagues in 1964. The purpose of Moseley’s graph was to simplify and improve the accuracy of calculations intended to estimate the ultimate discrepancy in growing children by incorporating into the calculations skeletal maturation based on hand-wrist bone films, growth inhibition, and relative size. In his words, “the growth of the legs can be represented by straight lines by a suitable manipulation of the scale of the abscissa.” As a consequence, with the nomogram of skeletal age to correct for percentile growth (i.e., relative size and skeletal maturation), the growth of the short leg is represented as a straight line, and the leg length inequality is represented as the vertical distance between the lines; the line indicating the growth of the shorter leg has a less steep slope compared with that of the longer leg, and the growth inhibition effected by epiphysiodesis can be indicated by altering growth inhibition (slope of growth of the longer leg) by the expected amount, based on the type of epiphysiodesis performed. The reference line in Moseley’s straight-line graph refers to the growth of the normal leg rather than the long leg (see Fig. 24-18 ). This is important because, in cases of overgrowth (e.g., hemihypertrophy), the abnormal leg should be plotted above the normal, shorter leg; this has a slight impact on the subsequent depiction of the limbs, the projected final discrepancy at maturity, and the timing of epiphysiodesis. (See Plate 24-1 on page 940 for a detailed discussion of the application of the straight-line graph method of Moseley.) In a review of 23 skeletally mature patients who had undergone epiphysiodeses for leg length inequality, Moseley found that his straight-line graph method yielded a mean error of 0.6 cm in predicting ultimate leg length inequality, compared with a mean error of 0.9 cm when the Anderson-Green-Messner growth-remaining method was used.

Some assumptions are incorporated into the construction and use of Moseley’s straight-line graph. Skeletal age–determined lengths of the femur and tibia do not exist for skeletal ages younger than 8 years in the data of Anderson and associates. Moseley assumed that individual patients maintained the same percentile skeletal age but acknowledged that this is not necessarily the case. In fact, Anderson and colleagues pointed out the tendency for longer femora to grow less and shorter femora to grow more with subsequent maturation (which is one reason that the accuracy of the Menelaus modification of the White-Stubbins method is comparable to that of the Moseley method). Finally, the straight-line determination of growth of the shorter (abnormal) leg presumes that growth inhibition is linear; however, as both Moseley and Shapiro pointed out, this is not necessarily true. Despite these problems, the accuracy of this method in practice is generally good, and we routinely use this method at our institution to determine leg length inequality at skeletal maturity and the appropriate timing of epiphysiodesis of the long leg.

Paley Multiplier Method

Paley and co-workers described the multiplier method to calculate leg length at skeletal maturity. These authors identified an arithmetic factor (multiplier) by dividing femoral and tibial lengths at skeletal maturity by the femoral and tibial lengths at different ages during growth for each percentile group, by using a variety of available leg length databases. The length of each leg and the difference in leg length at maturity (assuming constant growth inhibition) can be calculated by multiplying these measurements by the appropriate multiplier for the subject’s age and gender ( Table 24-4 ).

Summary of Prediction Methods

The application of published longitudinal growth data and the methods of calculating growth remaining to determine the appropriate timing of epiphysiodesis for leg length inequality have several areas of potential inaccuracy. Identifying the cause of leg length inequality in children is important for determining the ultimate discrepancy at skeletal maturity. For example, total physeal destruction from infection, fracture, irradiation, or surgical ablation results in fairly predictable growth retardation from loss of growth of the affected physis for the duration of remaining skeletal growth. Congenital limb deficiencies characteristically cause consistent growth inhibition of the affected leg, so that the percentage of shortening remains fairly constant during skeletal growth even as the absolute amount of discrepancy increases. However, Shapiro pointed out that not all growth inhibition in growing children is linear (i.e., results in a constant percentage of growth inhibition or acceleration in the affected limb), as implied by the standard graphic methods of calculating ultimate leg length inequality. Eastwood and Cole noted a linear increase in discrepancy in only 8 of 20 patients treated by epiphysiodesis.

Shapiro described 5 basic patterns of leg length inequality development based on an assessment of discrepancy development in 803 patients ( Fig. 24-17 ). Type 1 is an upward slope pattern, implying a stable percentage of growth inhibition compared with the normal leg. Type 2 is characterized by an upward slope–deceleration pattern. Type 3 is characterized by an upward (or downward) slope–plateau pattern and is most typical of post–femoral shaft fracture overgrowth. In Shapiro’s series, growth in 85% of patients with overgrowth had plateaued by 3.5 years after fracture. Type 4 is an upward slope–plateau–upward slope pattern, seen only in abnormalities involving the proximal femur, such as septic arthritis, Legg-Perthes disease, and avascular necrosis (AVN) associated with the treatment of developmental dysplasia of the hip. Type 5 is characterized by an upward slope–plateau–downward slope pattern, meaning that an initially increasing discrepancy actually decreases with subsequent growth.

Five patterns of altered limb growth as described by Shapiro. A, Upward slope pattern. This suggests a consistent rate of growth inhibition of the shorter leg. B, Upward slope–deceleration pattern. The rate of growth inhibition decreases over time. C, Upward slope–plateau pattern. After an initial constant growth inhibition, the legs grow at the same rate (plateau). D, Upward slope–plateau–upward slope pattern. A constant rate of growth inhibition is interrupted by a period of growth at the same rate. E, Upward slope–plateau–downward slope. The slower-growing limb exhibits an initial growth deceleration, followed by symmetric growth and finally increased growth compared with the contralateral limb.

In Shapiro’s series, the type 1 growth pattern was typical of patients with proximal femoral focal deficiency, Ollier disease (enchondromatosis), congenital femoral deficiency with more than 6 cm of shortening, physeal obliteration from any cause, and poliomyelitis. Some patients with congenital femoral deficiency with less than 6 cm of shortening or with poliomyelitis tended to exhibit a type 2 pattern. Patients with idiopathic hemihypertrophy or hemiatrophy demonstrated type 1, 2, or 3 patterns. Only 31% of patients with overgrowth associated with vascular anomalies had type 1 growth, and the remainder had a type 2 or 3 pattern. Patients with neurofibromatosis most commonly had a type 1 pattern, but types 2, 3, and 5 were also seen. Similarly, patients with juvenile arthritis exhibited types 1, 2, 3, and 5 patterns. Patients with Legg-Perthes disease exhibited all five patterns.

Prediction of leg length inequality based on serial scanograms, hand and wrist radiographs for skeletal age, and straight-line graph analysis ( Figs. 24-18 and 24-19 ) has other potential pitfalls as well. ^# Kasser and Jenkins, in a study of normal leg growth in normal children between 5 and 10 years of age, found that, except in girls with advanced bone age, the use of Greulich and Pyle’s atlas in preference to chronologic age did not improve the accuracy of predicting leg length at skeletal maturity. There was a mean error of 2.4 cm by the Anderson-Green-Messner method and of 2.6 cm by the Moseley straight-line graph method when the prediction was based on skeletal age. Blair and colleagues found that only 22 of 67 patients treated by epiphysiodesis had a final discrepancy of less than 1 cm. Ten of the 45 failures resulted from inadequate epiphysiodesis, and 35 were caused by incorrect use of the growth prediction charts of Anderson and associates. Little and colleagues also found that use of Greulich and Pyle’s atlas and either the Anderson-Green-Messner charts or Moseley’s straight-line graph did not improve the accuracy of prediction using the Menelaus method alone, which is based on chronologic age.

Moseley straight-line graph.

(Redrawn from Moseley CF: A straight-line graph for leg-length discrepancy, J Bone Joint Surg Am 59:174, 1977.)

Rotterdam straight-line graph. This modified straight-line graph was based on more modern growth data, and its originators found it to be more accurate in predicting leg length inequality and correction by epiphysiodesis than the Moseley straight-line graph. The method of use is the same as for the Moseley graph (see text, Fig. 24-18 , and Plate 24-1 on page 940 for details).

(Modified from Moseley CF: A straight-line graph for leg-length discrepancy, J Bone Joint Surg Am 59:174, 1977.)

# References .

Carpenter and Lester evaluated skeletal age (according to Greulich and Pyle’s atlas) in the distal radius and ulna, carpus, and metacarpals and phalanges in 100 hand and wrist radiographs of 45 children younger than 10 years of age. These investigators found significant discrepancies between skeletal and chronologic age among the regions of the hand and between the sexes. Cundy and colleagues assessed variations in the designation of skeletal age in 60 radiographs by 4 radiologists who were using Greulich and Pyle’s atlas. These investigators found that 50% of children were assigned a skeletal age that differed by more than 1 year, and 10% varied by more than 2 years. As Ferron pointed out, the standard deviation of Greulich and Pyle’s atlas is “plus or minus one page.”

Epiphysiodesis

History.

Phemister is credited with the first description of the technique of epiphysiodesis. Many reports and modifications of the procedure have followed. * ^a Phemister’s index case was a girl he described as having “dyschondroplasia” (Ollier disease), with shortening and curvature of the left upper and lower extremities. He “excised” the upper epiphysis of the left radius to correct the forearm deformity and the upper epiphysis of the right distal femur to arrest longitudinal growth. When the child was 8 years and 7 months old and had a 2½-inch leg length inequality, Phemister fused the right distal femoral physis through medial and lateral incisions, with excision of the cartilaginous disk to a depth of 1 cm with an osteotome and a bone graft slid distally from the metaphysis. At age 18 years, a ¾-inch elevation under the left heel “completely [did] way with” the residual discrepancy, although he measured the discrepancy at 2.5 cm. Phemister reported on 20 additional patients treated by epiphysiodesis for leg length inequality; he described the surgical technique and diagrammed the procedure ( Fig. 24-22 ). A piece of cortex measuring 3 cm by 1 to 1.5 cm and 1 cm deep was removed, and the underlying epiphysis was excised to a depth of 1 cm. The piece of cortex was replaced with its ends reversed. White and Stubbins modified the technique by using a ½-inch osteotome to fashion a ½- to 1-inch square straddling the physis in a diamond position, curetting the physis exposed by this plug, and reinserting it rotated 90 degrees from its original position ( Fig. 24-23 ). They reported no deformities resulting from more than 200 procedures that were “relatively free of complications.”

Phemister technique of epiphysiodesis of the distal femur and proximal tibia. A, A large rectangular bone block is removed from the lateral and medial aspect of the distal femur, proximal tibia, or both. B, Once the underlying physis is curetted, the bone blocks are reinserted after being rotated 180 degrees.

White and Stubbins technique of epiphysiodesis of the distal femur and proximal tibia. A, A square-sided cube of bone bridging the physis is removed. B, After the underlying physis is curetted, the cubes are rotated 90 degrees and replaced in their original beds.

References .

Green and Anderson also provided an early report of the results of epiphysiodesis. In their 1947 publication, they reported the results of 77 procedures in 50 patients performed with a variety of techniques by different surgeons in more than one center. The technique involved creating a “wide, thick graft extending at least 1 inch into the diaphysis, and at least 2 cm deep.” A hand drill was used to drill out the remaining physis, and the graft was reinserted after being rotated 180 degrees. In 77 epiphysiodeses, there were 5 cases of angular deformity (4 requiring corrective osteotomy), 1 deep infection, 1 transient peroneal palsy, and 3 cases of overcorrection. In their 1957 publication, Green and Anderson evaluated the results of 237 epiphysiodeses in 173 patients and 83 staplings. The results were good or excellent in the 173 epiphysiodesis patients, with few exceptions. Two had overcorrection greater than ½ inch, but 5 others underwent a contralateral epiphysiodesis to prevent overcorrection. Five patients developed angular deformity necessitating a corrective osteotomy in 4 and a repeat epiphysiodesis in 1. One patient developed osteomyelitis. Their overall rate of complications (including slow fusion) was 9.3%. The Green modifications of distal femoral and proximal tibial epiphysiodesis are described in Plates 24-2 and 24-3 on pages 942 and 946.

Percutaneous Methods.

Concern about the cosmetic appearance of two to four incisions around the knee has prompted interest in the percutaneous modification of epiphysiodesis. ^†a Bowen and Johnson described a percutaneous technique in which a portion of the physis is excised using stab incisions, curets, and fluoroscopic guidance. Canale and colleagues and Ogilvie demonstrated in animal experiments that percutaneous techniques using a combination of drills and high-speed burrs effectively produce the desired epiphysiodesis effect. This finding was subsequently substantiated by a number of authors in clinical series. ^‡a In all cases, a percutaneous stab incision is made directly over the physis to be ablated, and the physis is destroyed with various instruments ( Fig. 24-24 ). It is important that an adequate amount of physis be destroyed (Bowen attempted to leave only the central one third of the physis; others remove less), that the surgeon be attentive to the undulations of the physis, and that the physis be removed in an AP direction, as well as peripherally and centrally. Several technical variations have been described, including the use of a cannulated tube saw, cannulated reamers, reamers and curets, and osteotomes and curets. The proximal fibular physis can be curetted in an open fashion, excised percutaneously in an AP direction (with care taken not to injure the peroneal nerve), or, according to the recommendations of Stephens and colleagues, left intact if the patient has less than 3 to 4 years of skeletal growth remaining. Series comparing the Phemister and percutaneous techniques noted shorter hospital stays, more cosmetic incisions, and a less frequent need for postoperative physical therapy with percutaneous techniques. Horton and Olney reported continued growth after percutaneous and Phemister epiphysiodesis in 13% and 15% of cases, respectively, but all other authors have reported 100% closure rates after percutaneous epiphysiodesis, with few or no complications. ^§a

Technique of percutaneous epiphysiodesis. A, The physis is localized by fluoroscopy. B, The physis is removed with curets, a tube saw, or a drill under fluoroscopic control, with a sweeping motion superoinferiorly and anteroposteriorly across the radiographic line of the physis. C, An adequate amount of physis must be removed, usually leaving only a central bridge.

†a References .

‡a References .

§a References .

Epiphyseal Stapling

History.

Interest in mechanical disruption of normal physeal growth is as old as the concept of surgical epiphysiodesis described by Phemister. Haas described the retardation of bone growth by using a wire loop around the physis in a series of animal experiments. Successful retardation of growth in these experiments encouraged him to attempt this procedure in five patients, two of whom, both with polio, had adequate follow-up to allow him to describe the results. In both patients, stainless steel wire loops were passed around the distal femoral physis. In both cases, the wire loop broke and was replaced, but retardation of growth was noted, as was resumption of growth after fracture of the wire. This finding suggested the reversibility of the technique, with obvious advantages.

Haas subsequently conducted animal experiments using staples instead of wires, because wires tended to break. He noted deceleration of growth with staples when they were inserted medially and laterally. Growth of the operated segment increased after removal of the staples, but not to normal and not in all cases; this observation suggested surgical injury to the physis. When the staples were inserted unilaterally, there was a global decrease in growth of the operated physis, but this was greater on the side of staple insertion, thus producing an angular deformity. No clinical cases were reported by Haas.

It was left to Blount and Clark to report the use of staples clinically. They noted that one staple inserted across the physis would invariably break, and two tended to bend and occasionally break; however, if three were inserted, “growth will be stopped immediately and almost completely” ( Figs. 24-25 and 24-26 ). These investigators recommended open epiphysiodesis of the proximal fibula when tibial stapling was performed (done while the radiographs were developing). They emphasized that the three staples should span the physis and that their position should be verified on both AP and lateral radiographs.

Ideal spacing of staples, as recommended by Blount. Three evenly spaced staples should be placed extraperiosteally, with their tines parallel to the physis. A, Anterior view. B, Medial view.

Radiographs of a patient treated for persistent physiologic genu valgum by epiphyseal stapling of the distal femur, as described by Blount. A, Preoperative radiographic appearance. B, Postoperative appearance after stapling of the medial distal femur. Three staples on either side of the distal femur span the physis (see Figs. 24-59 and 24-60 ).

Results were reported in 13 patients—7 treated for leg length inequality and 6 for angular deformity. It is difficult to determine the precise rate of complications, but Blount and Clark believed that this technique stopped elongation at the operated site almost immediately, that this surgical procedure was less extensive and had a lower risk of complications than other methods, that “occasional complicating irregularities of growth following stapling” could be corrected by vigilance and rearrangement of the staples, and that growth at the epiphysis after removal of the staples was about the same as on the other side (sometimes faster, sometimes slower). Initially, stainless steel staples were used, but in a subsequent report, Blount found that Vitallium staples with reinforced shoulders were superior.

Results.

Green and Anderson, in the same publication describing the results of epiphysiodesis, evaluated 83 stapling procedures in 61 patients who had reached skeletal maturity. Stapling was found to be effective in inhibiting growth, although the distal femur grew an average of 6 mm after stapling. The incidence of complications was greater than after epiphysiodesis, but not significantly so; complications included slow arrest, asymmetric growth, and staple extrusion. The incidence of secondary operations after stapling was high, however, particularly in the proximal tibia. Green and Anderson also noted the “vagaries of growth which may occur after the removal of staples” and illustrated this with 2 patients. One patient grew at the distal femoral physis 2 mm more on the stapled side than on the opposite side after staple removal, and another patient did not grow at all after distal femoral stapling, thus resulting in 1.8 cm of overcorrection. Twenty-nine percent of the tibial staples and 14% of the femoral staples were removed; others were repositioned.

Bylander and colleagues, in a series of stereoscopic growth studies, found a gradual cessation of growth across the stapled physis over 6 months; this was accommodated by bending of the staples, which contributed to their loosening. Further experience with epiphyseal stapling was described by Blount and others. Blount recommended epiphysiodesis when there is an anticipated undercorrection (preferring stapling for angular deformity of the longer leg) or when surgery is performed in younger children (8 to 10 years old). The staples should be inserted parallel to the physis, and reinforced, smooth-tined Vitallium staples should be used ( Fig. 24-27 ). Blount reported that 426 operations were necessary in 185 patients, but only 2 patients required osteotomy for final correction. Frantz reported staple extrusion in 12 of 189 patients treated for either leg length inequality or angular deformity. Sengupta and Gupta believed that stapling is valuable in developing countries because of the relative simplicity of the procedure. These investigators found that 71% of 503 patients treated with stapling had less than 1 cm of discrepancy at skeletal maturity. Other studies have been less complimentary of the technique. May and Clements, in a review of 70 patients, noted that they had to remove staples in 50, had 24 extrusions, and had knee deformity in 10 patients. Trias and associates noted that 6 of 17 patients required osteotomy after staple removal.

Vitallium staples suitable for epiphysiodesis. The shoulders of the staples are reinforced to prevent bending of the tines with growth. The lack of barbs on the tines facilitates their removal, if necessary. A, Staples come in assorted sizes, with an inserter. B, Staple loaded in an inserter.

My experience with stapling has narrowed the indications for its use to nearly none. The procedure requires close attention to detail. Specifically, the proper staples must be used, and they must be evenly spaced around and parallel to the physis ( Fig. 24-28 ). The perichondrium and periosteum must not be stripped or otherwise damaged during either insertion or removal; if damage occurs, growth arrest will result. Careful postoperative monitoring of the patient is required. Theoretically, removal of staples after correction in a skeletally immature patient should be followed by symmetric, normal growth, with no further treatment required. In practice, however, the surgeon is placed in the unpleasant position of watching for evidence of the following: either rebound overgrowth, requiring further intervention, or the absence of growth, resulting in overcorrection of the leg length inequality; new angular deformity; or reverse angular deformity. Even when the patient reaches skeletal maturity without requiring staple removal or a readjustment in management, staples frequently must be removed because of soft tissue irritation from staple prominence or extrusion.

Proper technique of staple insertion. The physis is localized clinically or, preferably, fluoroscopically and is driven across extraperiosteally. Typically, three staples are inserted, evenly spaced across the physis.

Transphyseal Screws.

Métaizeau and colleagues described a modification of epiphysiodesis using percutaneously inserted transphyseal screws. These investigators inserted fully or partially threaded cancellous screws by using either a crossed-screw or nonintersecting-screw technique for the femur and tibia ( Fig. 24-29 ). They inserted a screw across the proximal fibula with an open technique to prevent injury to the peroneal nerve, and only when the tibial epiphysiodesis was expected to exceed 2 cm. In their series of patients with postfracture overgrowth and leg length inequality, Métaizeau and associates calculated an average reduction in distal femoral physeal growth of 68% after 6 months and 89% thereafter; for the tibia, physeal growth was reduced by 56% of normal in the first 6 months and by 95% thereafter. They also used this technique for angular deformity correction at the knee, as did Stevens and Belle at the ankle, with a percutaneously inserted screw in the medial malleolus.

Scheme of insertion of cannulated percutaneous screws for epiphysiodesis (after Métaizeau). A, Crossed screw insertion. B, Uncrossed, convergent screw placement.

In 2 of Stevens and Belle’s 41 patients, hemarthrosis developed postoperatively, without long-term sequelae. Serious complications included overcorrection of 1.3 cm because of failure to monitor the patient’s postoperative growth adequately and the development of varus angulation of the proximal tibia in 3 patients. The latter complication was attributed to overgrowth of the fibula when tibial growth retardation exceeded 2 cm and epiphysiodesis of the proximal fibular physis had not been performed. A theoretically attractive advantage of this technique is the prevention of overcorrection of angular deformity or leg length inequality by removing the screws after correction if the patient is not skeletally mature. In all likelihood, however, further experience will reveal that screw removal, similar to staple removal, has an uncertain result with respect to the resumption of growth or a rebound effect. I have no experience with this technique.

Acute Shortening

Shortening the longer leg by the removal of bone and fixation has several appealing attributes. Surgical shortening is a single-stage procedure with a lower complication rate than either acute or gradual lengthening. ^‖a In contradistinction to epiphysiodesis, the surgeon need not rely on the vagaries of skeletal age and maturation. The only calculation required is the extent of bone to be resected, along with a consideration of whether a tibial or femoral segment should be removed to gain symmetric knee height. Conversely, the likelihood and severity of complications are higher for surgical shortening than for epiphysiodesis, and significant muscle adaptation and rehabilitation are required. In addition, the technique is often met with the same initial resistance as epiphysiodesis, in that patients and their families are usually not keen to sacrifice length for safety or expediency—at least until they appreciate the risks and intensity of treatment. Femoral ^¶a or tibial shortening techniques can be performed. Combined one-stage femoral shortening and contralateral femoral lengthening using the segment of bone from the shortened side can also be performed. The most likely indication for this combined approach is a discrepancy greater than ideal for shortening alone in a patient who is not a candidate for gradual lengthening of the shorter limb.

‖a References .

¶a References .

Femoral Shortening

Indications.

Acute femoral shortening for the purpose of equalizing leg length has been described by many authors ( Fig. 24-30 ). ^#a Acute shortening of the femur is a relatively major procedure and is generally indicated only in skeletally mature individuals with a leg length inequality greater than 2 cm. Discrepancy localized to the femur and average stature are preferable to maintain adequate overall stature and symmetric knee height after the procedure. Shortening can be undertaken in the proximal, middle, or distal portion of the femur. In general, if the patient has an associated angular deformity, osteotomy for angular correction and shortening should be at the level of deformity. In the absence of deformity, shortening can be at the subtrochanteric or mid-diaphyseal level; distal metaphyseal shortening is less desirable because of the incongruity of the bone segments after shortening resulting from the funnel shape of the distal femur. Internal fixation may be achieved with a proximal femoral blade plate, plate and screws, or intramedullary rod.

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