Congenital Tibial Deficiency

Review Article Congenital Tibial Deficiency

Abstract Jody Litrenta, MD Congenital tibial deficiency is a rare condition characterized by partial Megan Young, MD to complete absence of the tibia, an intact but frequently overgrown fibula, variable degrees of knee deformity and function, and an John G. Birch, MD abnormal equinovarus foot. It can occur in isolation but also presents Matthew E. Oetgen, MD, MBA concurrently with other orthopaedic anomalies and syndromic conditions. Among these, congenital abnormalities of the hand and femur are most commonly observed. Many theories exist regarding its etiology and some genetic mutations have been identified; however, the underlying mechanism remains unknown. The prognosis and treatment differ based on the clinical severity. The goal of treatment is always to create a stable, functional limb, most commonly with amputation and use of prosthetics. Controversy exists over the level of amputation and the usefulness of reconstructive procedures to preserve the foot and limb length. Current investigation on this complex disorder is focused on identifying its origins and further developing a classification-based treatment algorithm to improve patient outcomes.

’ From the Children s National Health ongenital tibial deficiency oc- ectodermal ridge, the zone of polar- System, Division or Orthopaedic 1 Surgery and Sports Medicine, Ccurs in 1 in 1 million live births. izing activity (ZPA), and the Wnt Washington, DC (Dr. Oetgen, It exhibits a spectrum of disease, signaling pathway. Cell-mediated in- Dr. Young), NYULMC Hospital for Joint with varying amounts of tibia absence teractions among these centers occur Diseases, New York, NY (Dr. Litrenta), contributing to a range of associated between the 4th and 7th week of ges- and Texas Scottish Rite Hospital for Children, Dallas, TX (Dr. Birch). knee and foot abnormalities. Knee tation. The apical ectodermal ridge instability is frequently present, with modulates the proximal to distal Dr. Oetgen or an immediate family member serves as a board member, the most severe forms of deficiency development. The ZPA produces sonic owner, officer, or committee member lacking a patella and a knee extensor hedgehog (Shh) protein, which directs of the American Academy of mechanism. Very severe forms also anterior versus posterior orientation; Orthopaedic Surgeons, the Pediatric often have a skin dimple overlying the Orthopaedic Society of North this becomes radioulnar in the upper America, and the Scoliosis Research proximal tibia and accompanying limb and the tibia and fibula in the Society. Dr. Birch or an immediate knee flexion contracture. In less severe lower limb. The dorsal limb bud se- family member has received royalties cases, the proximal tibia and knee cretes Wnt protein, which distinguishes from Orthofix. Neither of the following extensor mechanism are present and 6 authors nor any immediate family dorsoventral development. member has received anything of the knee is stable. The fibula is typi- Most limb deficiencies are present value from or has stock or stock cally intact, and the foot position by the 7th week of gestation. The options held in a commercial company varies in relation to the knee, with upper limb develops after day 28 and or institution related directly or supination and rigid equinovarus of indirectly to the subject of this article: the lower limb by day 31, and both the foot most commonly observed.1-5 Dr. Litrenta and Dr. Young. progress proximal to distal. Upper J Am Acad Orthop Surg 2019;27: and lower limb abnormalities appear e268-e279 Embryology after days 35 and 37, respectively. DOI: 10.5435/JAAOS-D-16-00838 Although the exact cause and timing In normal embryologic development, of tibial deficiency remain unknown, Copyright 2018 by the American Academy of Orthopaedic Surgeons. limb bud orientation progresses the responsible insult likely occurs under three influences: the apical during this phase.7

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One theory for the cause of limb Table 1 deficiency is vascular insufficiency. 8 Percentage of Observed Associated Pathology in the Two Largest Series Levinsohn et al reported on tibial of Congenital Tibial Deficiency and fibular deficiency and clubfoot. 2 5 In all cases, they found similar pat- Schoenecker et al Clinton and Birch Associated Pathologies (57 pts) (%) (95 pts) (%) terns of arterial deficiencies, involv- ing the anterior tibial and dorsalis Overall 60 78 pedis artery. Vascular insufficiency can Bilateral 25 32 create either pre- or post-specification Upper extremity 30 33 defects, depending on the timing in Cleft hand 9 16 relation to mesenchymal differentia- Radial deficiency 1 8 tion. Post-specification defects leave a Other 20 9 rudimentary structure, which, the au- Lower extremity 48 96 thors postulate, explains tibial defi- Deficient lateral rays 9 21 ciency given the presence of a partially Medial ray/great toe duplication — 14 formed proximal tibia. However, Hip dysplasia or dislocation 18 11 others speculate a pre-specification Congenital femoral deficiency 9 11 cause, because the limb bud starts off Coxa valga 12 — in close proximity to the mesenchyme Other — 40 of other vital organs, providing an Visceral NAa 43 explanation for the coexistence of other Cardiac — 21 systemic developmental anomalies.3 Gastrointestinal — 15 Genitourinary — 7 Spine 21 12 Genetic Basis a Visceral organ involvement not reported by Schoenecker et al. No specific gene mutation has been identified as the cause of congenital tibial deficiency. The Shh pathway and foot syndrome, and tibial hemimelia- most common hip abnormality was has been implicated in syndromic micromelia-trigonobrachycephaly congenital dislocation (10 patients), forms.9 Recent research has identified syndrome. Among these disorders, a followed by coxa valga and proxi- a 5 kb deletion within the DNA of the wide range of clinical expression ex- mal focal femoral deficiency. Hand Shh repressor Gli3 protein in two ists, supporting variable penetrance. deformities were also prevalent, patients with bilateral tibial defi- For example, in a series of 37 patients occurring in 17 patients (30%). ciency, resulting in unrestricted Shh with tibial hemimelia–split hand and Spine abnormalities were present in activity outside the ZPA.10 This study foot syndrome, severity ranged from 12 patients (21%), including 5 with also noted that the genetic deletion isolated digit hypoplasia or syndac- hemivertebrae, as well as hypoplastic occurred only on the maternal allele, tyly to complete bilateral tibia agen- vertebrae, scoliosis, and spina bifida. suggesting autosomal-dominant inher- esis with split hands.15 Interestingly, 20 patients (35%) itance with incomplete penetrance.10 reported a family history of con- However, both autosomal-dominant genital anomalies ranging from hand and autosomal-recessive inheritance Associated Pathology deformities (10 patients) to congen- models have been described,11-13 and ital tibial deficiency (5 patients). case reports of additional chromo- Other congenital abnormalities are Most of these were in first-degree somal abnormalities exist.14 There observed with high frequency. Con- relatives. are likely multiple genetic alterations genital hip dislocation, vertebral A more recent study by Clinton and and inheritance patterns responsible malformations, bifurcation of the Birch5 details a longitudinal series of for tibial deficiency. femur, imperforate anus, and hypo- 95 patients spanning 37 years at Syndromic forms of tibial deficiency spadias have been reported.2,3,16 In Texas Scottish Rite Hospital. Among also exist, with four known associated an older series of 57 patients studied these patients, 79% had other autosomal-dominant types: Warner’s by Schoenecker et al,2 34 patients abnormalities, consistent with pre- Syndrome, tibial hemimelia diplopodia (60%) had an associated abnormal- vious reports. These were mostly syndrome, tibial hemimelia–split hand ity of the hip, hand, or spine. The other lower extremity anomalies,

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Table 2 cation based on their experience. They simplified the Jones classifica- Number of Observed Additional Upper Extremity, Lower Extremity, and Spine Abnormalities, Organized by Jones Type in 71 Limbs Described by tion into three groups, omitting Schoenecker et al2 Jones type 3 patients because this form was never encountered at their Upper Extremity, Lower Extremity, Spine, Type No. (%) No. (%) No. (%) Total Limbs institution. Arguing that 15% of patients could not be described ac- 1A 6 (18) 12 (36) 5 (15) 33 cording to the Jones method, Weber 1B 1 (17) 3 (50) 2 (33) 6 created a more elaborate classifica- 2 2 (12) 6 (37) 3 (19) 16 tion, incorporating seven categories 3 3 (43) 1 (14) 1 (14) 7 from “best” to “worst” and 5 sub- 4 4 (44) 1 (11) 1 (11) 9 categories based on the presence or Totals 16 (23) 22 (31) 12 (17) 71 absence of a tibia cartilaginous anlage, which affects reconstruction. Type 1 is hypoplastic, type 2 is distal Table 3 diastasis, type 3 is distal aplasia, Number of Observed Additional Upper Extremity, Lower Extremity, type 4 is proximal aplasia, type 5 Visceral Organ, and Spine Abnormalities, Organized by Jones Type in 125 is bifocal aplasia, type 6 is agenesis 5 Extremities Described by Clinton and Birch with a double fibula, and type 7 is Upper Lower agenesis with a single fibula (Figure 3). Extremity, Extremity, Visceral, Spine, Total A final classification system, first Type No. (%) No. (%) No. (%) No. (%) Limbs proposed by Paley21 in 2003 and later 1A 23 (32) 44 (60) 23 (32) 12 (16) 73 modified, describes both the progres- 1B 1 (17) 1 (17) 1 (17) 1 (17) 6 sive spectrum of deficiency and the 20,21 2 6 (33) 11 (61) 5 (28) 4 (22) 18 treatment algorithm for each type 3 1 (50) 2 (100) 0 (0) 0 (0) 2 (Figure 4). Type 1 represents a con- 4 4 (33) 5 (42) 2 (17) 0 (0) 12 genitally short tibia with relative fibula 5 2 (14) 12 (86) 2 (14) 1 (7) 14 overgrowth. In type 2, the proximal Totals 37 (30) 75 (60) 33 (26) 18 (14) 125 and distal epiphyses are present with a dysplastic ankle. The tibia plafond is absent or deficient in type 3 with distal such as absent lateral rays and hip “worst” to “best,” based on the diastasis. Only the proximal tibia is dislocation. Upper extremity anom- skeletal morphology of radiographs present in type 4. Type 5 represents alies, such as cleft hand, radial defi- of affected infants.17 Type 1, which the most severe with complete absence ciency, and congenital scoliosis, also lacks any tibial ossification, has two of the tibia (Table 4). occurred. Congenital tibial deficiency, distinct clinically relevant subgroups. unlike other longitudinal deficiencies, Type 1b contains a cartilaginous is particularly notable for associated anlage, whereas type 1a has no carti- Epidemiology Based on the visceral organ involvement. This series lagenous anlage and further has a Jones Classification noted that 20 patients had an hypoplastic distal femoral epiphysis. associated cardiac malformation, 14 Type 2 demonstrates ossification of Schoenecker et al2 presented in their had a gastrointestinal malformation, the proximal tibia. In type 3, the least report a distribution of commonly and 7 had a genitourinary congenital common form, isolated ossification of encountered forms. Type 1a and 2 abnormality. These two studies are the distal tibia is seen. Type 4 is short deficiencies were the most common, the largest reports of observed con- tibia with an absent distal articular representing 46% and 21% of the genital anomalies (Tables 1–3). surface and distal tibiofibular diastasis series, respectively. Type 4 occurred (Figures 1 and 2). Although this clas- in 14%, and type 3 and 1b were the sification scheme remains the most least common, affecting 9% and 8% Classification Systems widely adopted, limitations exist of limbs, respectively. In this series, owing to the broad clinical spectrum no limbs were described that did not The Jones classification is the most of the condition. fit the Jones classification. commonly used system, dividing tib- Kalamchi and Dawe18 and Consistent with Schoenecker et al, ial deficiency into four groups, from Weber19 modified the Jones classifi- Clinton and Birch5 reported a similar e270 Journal of the American Academy of Orthopaedic Surgeons

Copyright © the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited. Jody Litrenta, MD, et al epidemiologic pattern of tibial defi- Figure 1 ciency. Among them, type 1a was the most common, occurring in 58% of limbs. Type 2 was the second most common, occurring in 14%. No limb was truly type 3, because all eventually developed a proximal tibia epiphysis on radiographs. Fourteen of 95 limbs (11%) were characterized by more global tibial deficiency and deemed not classifiable by Jones criteria. All patients had similar radiographic appearance, with proximal and distal tibia epiphyses, and proximal and distal fibula overgrowth leading the authors to propose a distinct “Jones 5” group. Of note, a wide range of deformity coexisted with this group which affected management. Table 5 details the relative frequency of Jones types observedinthesetwolargeseries.

Clinical Features

A broad spectrum of clinical pathology exists in congenital tibial deficiency. Physical examination of the affected limb follows the Jones classification. In Jones type 1a, with complete tibial aplasia, hamstring function is present and quadriceps function is deficient, causing knee flexion contracture. The patella does not form, and the foot is in rigid equinovarus. In Jones type 1b and 2, the knee extensor mechanism is formed, producing a functional knee Jones classification of congenital tibial deficiency. (Reproduced with permission without contracture. The fibula dis- from Jones D, Barnes J, Lloyd-Roberts GC: Congenital aplasia and dysplasia of places proximally and laterally, and the tibia with intact fibula: Classification and management. J Bone Joint Surg Br an equinovarus foot is noted. In Jones 1978;60:31-39.) type 3, with isolated distal tibia ossification, the knee is unstable, with for initial orthopaedic referral. An the treatment and prognosis are varus positioning of the overall limb. atypically rigid clubfoot, absent vastly different (Figure 5). Jones type 4 patients have a stable lateralrays,ormedialrayduplica- In addition to the characteristic knee and a rigid equinovarus foot tion should alert the orthopaedic clinical findings, congenital tibial positioned in the diastasis between surgeon to investigate for tibial deficiency is distinctive for frequent the tibia and fibula. deficiency. We stress the importance associated congenital abnormalities, The equinovarus foot position of fully evaluating the entire lower which do not correlate well with any akin to all types of congenital tibial extremity for clues that the equi- classification system. Other orthopae- deficiencycanbeconfusedwithan novarus foot may be a manifestation dic anomalies are commonly encoun- isolated clubfoot, a common reason of a longitudinal deficiency, because tered in all forms, and a thorough

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Figure 2 physical examination of all extremities, hips, and the spine is essential with a low threshold to obtain additional imaging. Because of the risk of associated visceral organ abnormalities, we recommend a genetics consultation and advanced imaging to evaluate for other organ dysfunction.

Surgical Intervention

The most fundamental treatment principle is to determine whether the knee is stable with a functional extensor mechanism. Type 1a deficiencies lack any tibia. Hamstring function but not quad function is present, creating a nonfunctional contracted and displaced knee joint proximal and lateral to the femoral condyles. For this reason, the standard management of Jones type 1a tibia deficiency is knee disarticulation. In all other types of tibial deficiency, with a theoretically functional knee, an attempt is made to reconstruct the proximal tibia and fibula and preserve the knee joint. Because of the severity of foot and ankle deformity and instability, the distal limb is often managed with a Syme amputation and prosthetic fitting. For Jones type 1b and 2 limbs in which varying ossification of the proximal tibia is present, traditional management consists of proximal tibiofibular synostosis and distal Syme amputation. It is vitally important to differenti- ate type 1a and 1b deficiencies because these types distinguish a nonfunctional and functional knee and extensor mechanism. Though less commonly encountered, in type 1b deficiency, the cartilaginous anlage of the proximal tibia will ossify, al- lowing the knee joint to be preserved. Ultrasonography is a simple method that can identify a cartilaginous tibial anlage predictive of future ossification. Additionally, ultrasonography Radiographic examples of each Jones type of congenital tibial deficiency. elucidates the presence of other e272 Journal of the American Academy of Orthopaedic Surgeons

Copyright © the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited. Jody Litrenta, MD, et al important components of knee stabil- Figure 3 ity, including an intact patella tendon and functioning quadriceps mechanism.22 Advanced imaging with MRI provides more precise detail, and in some cases, it may be helpful in determining whether knee reconstruction options are possible and aid in surgical preparation.23 The rare Jones type 3 deficiencies are commonly managed with a Syme or Chopart amputation, assuming eventual ossification of a proximal tibial cartilaginous anlage and a functional quadriceps mechanism. Similarly, the modified Syme ankle disarticulation has been the standard management of type 4 deficiencies associated with dis- taldiastasis.Alternatively,lengthening and reconstruction options that repo- sition and achieve a plantigrade foot may be possible. Foot preservation techniques are often hindered by the Weber classification of congenital tibial deficiency. (Reproduced with permission absent distal tibia and notable de- from Weber M: New classification and score for tibial hemimelia. J Child Orthop 2008;2:169-175.) formities of the talus and calcaneus.

ization procedure. Epps et al26 function, despite the fact that one Brown Procedure published a series of 14 patients with had a knee flexion contraction and complete tibial deficiency treated another had a limited range of In 1965, Brown24 described a fibular within the first year of life. All pa- motion. Similarly, Simmons et al28 centralization procedure for congenital tients developed severe flexion defor- reviewed seven patients followed an tibial deficiency. In this procedure, a mity of the knee which impaired gait average of 7 years after Brown pro- U-shaped incision was made at the and interfered with prosthetic wear, cedure and also documented good level of the knee joint and the fibula and they underwent secondary sur- results. The average arc of motion was dissected from the surrounding geries to manage either the flexion was 57°, and all were ambulating soft tissues through a lateral para- deformity or knee disarticulation. The with patellar tendon–bearing pros- patellar arthrotomy. The proximal 3/8 seven patients who underwent knee theses and thigh extensions for col- inch of the fibular epiphysis was os- disarticulation obtained a satisfactory lateral support. Both Christini and teotomized to make a flat surface and result, whereas the others remained Simmons found that the Brown was then centralized and fixed with limited by their knee flexion contrac- procedure may lead to subjectively K-wires underneath the femoral con- ture at final follow-up. Clinton and reported acceptable function in dyles. The soft tissues were imbricated Birch5 also noted a high rate of knee patients with complete tibial defi- to centralize the patella and tighten the disarticulation after the Brown pro- ciency, as long as they had a func- capsule; distally, the patellar tendon cedure and knee flexion contractures tioning quadriceps of at least grade 3 was reattached to the centralized fib- in a small number of patients who did strength preoperatively. Other ula. This procedure was largely un- not have further revision surgery. important criteria for a functional dertaken in Jones type 1a patients. Although a high rate of conversion outcome included the absence of Although initial enthusiasm was pre- to knee disarticulation is present, the fibular bowing and pterygium folds sent, a 15-year follow-up study re- Brown procedure has been successful in the popliteus fossa which lead to vealed that most of these patients went in patients who meet certain in- progressive flexion contractures, on to have a knee disarticulation.25 dications. Christini et al27 found that and age less than 1 year so the Other series similarly reported poor 5 of 13 patients who underwent the fibula has adequate time to hyper- outcomes after the Brown central- Brown procedure had acceptable trophy with growth.27,28

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Figure 4 distal femur, but long-term functional outcome studies are unavailable.

Reconstruction Principles

Advances in technology, our knowl- edge of biology, and better understanding of the pathology of all types of tibial deficiency may lend alterna- tive treatments to amputation in the future even for the most severe types. Certain principles apply for reconstructive surgery to successfully create a functional limb in the hands of an experienced surgeon. No single intervention can address the complexity of the limb deficiency. Multi- ple staged procedures to realign, recreate and stabilize the joints, and lengthen the leg must be anticipated. A plantigrade foot and stable ankle must be achieved. Reconstruction of the knee, restoration of a functional extensor mechanism, and elimination of the flexion contracture must be Paley classification of congenital tibial deficiency. (Reproduced with permission addressed. Repeated lengthenings from Paley D: Tibia hemimelia: New classification and reconstructive options. of the tibia or centralized fibula J Child Orthop 2016;10:529-555.) mayberequiredandtheadjacent joints must be stabilized. Paley21 elaborately described reconstruc- Notable advantages exist in selecting functional knee mechanism. In 2002, tion options that correspond to his a more distal level of amputation to Weber29 proposed a technique in classification of tibial deficiency preserve the native knee joint. Pa- which the patella anlage is trans- (Table 4). Functional outcome tients benefit from improved energy posed to articulate with the distal studies of these new and modified expenditure, gait efficiency, and femur. To facilitate the transposi- techniques are unavailable. proprioception. Although fibular tion, the quadriceps tendon is centralization appears to be unsuc- Z-lengthened and stabilized by the cessful for many patients with com- creation of two visor flaps made Distal Amputation Versus plete tibial deficiency, those who from the surrounding capsular tissue Reconstruction demonstratesomepreoperativeactive and crossed to provide medial and knee function may be candidates. lateral support. The fibula can then Less controversy exists over the Identifying these patients by thorough be centralized below the patella and management of partial tibial defi- physical examination and adjunct attached to the patella tendon. The ciency (Jones Ib-Jones 2). A tibio- ultrasonography will help select construct is supported with a ringed fibular synostosis can be performed appropriate patients for the Brown fixator, which gradually increases by first osteotomizing the fibula at the centralization procedure. the range of motion of the new knee neck and fusing the distal portion of joint. In theory, this surgical tech- the fibula to the remnant tibia in an nique improves on the Brown cen- end-to-end or side-to-side fashion Knee Reconstruction tralization by adding better knee with supplemental screw or plate and stability through the creation of screw fixation (Figure 6). Because Given the mixed results of the Brown the capsular visor flaps and by using the fibula typically is migrated procedure, other surgical techniques the patella to provide a larger, more proximally, the technique involves have been developed to recreate a stable articulating surface for the resecting the proximal fibula to e274 Journal of the American Academy of Orthopaedic Surgeons

Table 4 Paley Classification and Reconstruction Principles Paley Classification Features Reconstruction Options

1 Congenitally short tibia overgrown fibula Correction of valgus deformity and lengthening Proximal valgus Normal distal plafond 2 Deficient tibia plafond with diastasis of tibia and Reconstruction of ankle joint fibula Foot follows the fibula Correction of any tibia deformity 1 lengthening 3a Distal tibia physis formed but separate from Reconstruction of ankle joint proximal physis Plafond dysplastic Correction of tibia deformity 1 lengtheninga Overgrown fibula Fibula management:(1) resection of diaphysis to create non-union and (2) distraction of tibia without fibula fixation 3b Delta tibia representing proximal and distal physis Excision of bracket connected through bracket epiphysis Malorientation of knee and ankle Acute correction of tibia deformity 1 partial resection fibula Overgrown fibula Lengtheninga 4a Delayed ossification of tibia Creation of plantigrade foot with stable ankle Absent distal physis Correction of tibia deformity Ankle joint present but nonfunctional Lengthening after anlage ossifiesa Overgrown fibula 4b Complete absence of distal tibia Correct foot deformity Overgrown fibula Fuse talus to distal fibula Transfer fibula diaphysis to distal end of proximal tibia Future lengthening of single bone lega 4c Proximal epiphysis present but absent physis Correct foot deformity and knee contracture Knee joint present Fuse talus to distal fibula Notable overgrown fibula Fibula fixed to tibia epiphysis Repeated future lengtheningsa 5a Complete absence of tibia Patella converted to a tibia plateau Patella present Fibula centralized to patella (Weber procedure) Knee flexion contracture 5b (i) Complete absence of tibia Correction of knee contracture No patella Centralize foot to distal fibula Knee flexion contracture Reconstruction of knee ligaments and transfer quad to fibula Fibula autocentralized Fuse talus to fibula Repeated future lengtheningsa 5b (ii) Same as 5b (i) Centralize fibula to femur Fibula dislocated Correction of knee contracture Centralize foot to distal fibula Repeated future lengtheningsa

a Recommends extending the external fixator to the femur to stabilize the knee.

avoid prosthetic fit problems from maintains the heel pad, or Boyd ostosis in 8 of them. Christini the protruded fibular head. Re- amputation, which differs because recommended the Boyd procedure growth of the resected proximal the calcaneus is retained, centralized, instead of a Syme amputation if the fibula may be prevented by removing and fused to the proximal limb. calcaneus can be centralized, and the periosteum. Schoenecker et al2 used distal Syme some surgeons suggest that retaining Distally, the limb is traditionally amputation in 12 patients with type the calcaneus better maintains the managed with either a Syme ampu- 2 deficiency and successfully com- heel pad position.27 The Boyd pro- tation, an ankle disarticulation that bined this with tibiofibular syn- cedure is technically more difficult

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Table 5 Figure 5 Relative Frequency of Observed Forms of Congenital Tibial Deficiency in the Two Largest Series, Organized by Jones Type Schoenecker et al2 Clinton and Birch5 Type (71 Limbs) (%) (125 Limbs) (%)

1a 46 58 1b 8 5 22314 3102 41310 Unclassifiable 0 11 Clinical photograph of an extremity affected by congenital tibial deficiency. than the Syme, and good functional The goals of this procedure are to outcome is achieved through the use obtain a plantigrade foot, a stable Another long-term study evaluated of a prosthetic with either amputa- and functional knee joint, and a sta- the outcomes between patients with tion. However, some surgeons ad- ble ankle joint with arthrodesis, as primary amputation and those with vocate for distal reconstruction, well as to equalize leg lengths. The use distal foot reconstruction using the which depends on the length of the of distraction osteogenesis provides Pediatric Quality of Life question- affected limb and the amount of gradual centralization of the foot and naire. Although the scores were not deformity present in the foot. Dif- eventual lengthening of the extrem- statistically different, in many areas ferent combinations of limb leng- ity. Although successful in achieving patients with reconstruction scored thening and foot centralization and these goals, this approach requires slightly higher. However, it should be reconstruction have varying success. multiple surgeries and has a high rate noted that the amputation group The first report of foot centraliza- of complications. On average, pa- was a much smaller group of patients tion was by Hosny.30 In addition to tients underwent an average of 6.4 and had proportionately more bilat- performing fibular centralization, an surgeries, spent 17 months in an eral cases than the reconstruction Ilizarov frame was used to center the external fixator, and experienced 5.5 group. Although distal reconstructive foot underneath the fibula. Since complications. The severity of these procedures require long treatment then, several series have detailed the complications varied, including knee times in a frame and high rates of results.31-33 In a recent publication, subluxation or dislocation, knee complications, many patients and Balci et al32 presented a clear protocol flexion contracture, equinus defor- families select this option and report for foot centralization and the results mity, fracture through the regenerate, good satisfaction rates.33 in 17 patients with partial tibial revision of the circular fixator, and deficiency. Their protocol involved pin tract infections. It is also impor- initially addressing the ankle, fol- tant to note that the functional Timing of Surgical lowed by centralization of the fibula outcomes after this reconstructive Intervention under the remaining tibia. Achilles procedure compared with knee dis- tenotomy and posteromedial release articulation in Jones 1a deficiency The optimal time to proceed with were performed first to mobilize the were not different. Furthermore, surgical intervention may be individ- foot. Next, the posterior facet of 13 of 23 patients who underwent ualized. Amputation is best performed the calcaneus was centralized under reconstruction required bracing treat- between the ages of 6 months and 1 the fibula with a circular external ment or crutches at long-term year to allow early prosthetic fitting at fixation. Finally, the fibula was os- follow-up, including all of Jones type the onset of walking. Patients with an teotomized and centralized beneath 1 patients.32 Finally, neither report additional upper extremity deficiency the tibia and held with a Steinman specifically discusses the outcomes of present an exception to this rule. De- wire. Distraction osteogenesis for feet with or without deficient lateral laying lower limb amputation is limb lengthening in a staged fashion rays. It is logical to consider that the appropriate until surrogate use of the was performed, once the distal fibula status of the foot may in part dictate lower extremity to replace the upper had healed to the proximal tibia and the success of centralization, but this extremity is established. For manage- had expanded to its width. has not been reported. ment of partial tibia hemimelia, a e276 Journal of the American Academy of Orthopaedic Surgeons

Copyright © the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited. Jody Litrenta, MD, et al proximal tibiofibular synostosis can Figure 6 be performed when sufficient ossification of the upper tibia develops to permit successful union, but Jones argued that stability can be achieved with fusion to the cartilaginous anlage that will eventually ossify.17 The surgical plan may vary considerably with multiple staged procedures anticipated to achieve a functional limb for patients suitable for more complex reconstruction procedures. Brown24 initially recommended fibular centralization surgery by 1 year of age to maximize early ambulation, fibular articulation, and hypertrophy potential. Similarly, the Weber29 procedure was first described in a 15-month-old child. Paley recommends achieving a stable ankle and plantigrade foot, followed by secondary procedures to create a one-bone leg and reconstruct the knee.20,21 The timing of additional lengthening procedures is driven by the projected discrepancy, expected number of procedures, the child’s functional needs, and pre- paredness of the family for lengthening surgery. In general, the discrepancy should be addressed with as few surgeries as possible to Radiographic example of a patient after tibiofibular synostosis. achieve acceptable alignment, a plantigrade foot, a stable knee, and equal limb lengths by the time of the day. Although most of them do reference values. However, adoles- skeletal maturity. Serial lengthenings not have problems with pain, in one cents reported less diversity in the can be spaced throughout childhood survey, 16% reported having at activities they participated in and less to allow sufficient time without least moderate pain.34 Pediatric involvement in social and skill-based surgery. We suggest engaging the patients with prosthetics may struggle activities. None of these findings parents in a discussion of treatment compared with their peers. Their correlated with the degree of limb options at the initial consultation different appearance and physical deficiency.35 and beginning reconstruction within limitations compared with typically This research does highlight the fact the first few years of life. developing children may predispose that children with limb deficiencies them to difficulty with psychosocial and prosthetics are a highly adaptive adjustment. group who enjoy participation in Psychosocial Outcomes Michielsen et al evaluated a group leisure activities. It is notable that of 56 Dutch children and adoles- adolescents did struggle in a few Children with limb deficiencies cents with lower limb deficiencies. areas. It would be worthwhile to experience a high level of function. In this assessment, 8- to 18 year olds examine the transition from child- Overall, they are better equipped reported their participation in lei- hood to adolescence in this pop- than the adult population to deal sure activities and their health- ulation and better understand what with a prosthetic limb. Most pa- related quality of life. Their general contributes to their differences. tients are able to wear their pros- participation and health-related qual- Furthermore, comparisons between thetic for long intervals during ity of life were not different from patients with limb reconstruction

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Copyright © the American Academy of Orthopaedic Surgeons. Unauthorized reproduction of this article is prohibited. Congenital Tibial Deficiency and those with amputation may other syndromes and organ dysfunc- 10. Deimling S, Sotiropoulos C, Lau K, et al: Tibial hemimelia associated with GLI3 better describe how these procedures tion, it is important for each patient to truncation. J Hum Genet 2016;61:443-446. affect childhood. be thoroughly evaluated for coexist- 11. Clark MW: Autosomal dominant ing congenital anomalies. Addition- inheritance of tibial meromelia: Report of a ally, more clearly understanding the kindred. J Bone Joint Surg Am 1975;57:262. Summary psychosocial needs of affected chil- 12. Leite JA, Lima LC, Sampaio ML: Tibial dren may in turn allow healthcare hemimelia in one of the identical twins. 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