Orthoses

If the child is younger than 3 years old and the lesion is no greater than Langenskiöld stage II, orthotic treatment is recommended because 50% or more of these patients can be successfully treated with braces, especially if they have only unilateral involvement. There may be an inclination to brace patients before a true Blount lesion is visible on radiographs, particularly when the MDA is suggestive of varus progression. Thus when evaluating the reported good outcomes from brace treatment, one must realize that some patients probably had physiologic genu varum rather than true infantile tibia vara. Nevertheless, orthotic treatment appears to affect the natural history favorably.

The type of orthosis prescribed and the length of time that the orthosis is worn during a 24-hour period vary. Raney and associates used a knee-ankle-foot orthosis (KAFO) that produced a valgus force by three-point pressure in 60 tibiae (38 patients), with lesions in 54 tibiae (90%) resolving without surgery. Significant risks for failure included ligamentous instability, patient weight greater than the 90th percentile, and late initiation of bracing. Of the 54 tibial lesions that resolved, 27 were treated by full-time orthotic use, 23 by nighttime use only, and 4 by daytime use. Three of the six tibiae requiring surgery had been treated with full-time orthotic use and three with nighttime use only. Based on these findings, the authors conjectured that nighttime-only bracing might be as efficacious as full-time bracing, although they acknowledged that one inherently would expect daytime use (i.e., during weight bearing) to be the most important factor in successful orthotic treatment. On the other hand, Zionts and Shean reported daytime ambulatory bracing to be successful in altering the natural history of tibia vara in patients younger than 3 years with Langenskiöld stage I or II disease.

We have used conventional KAFOs, conventional hip-knee-ankle-foot orthoses (HKAFOs), and elastic KAFOs in the treatment of infantile Blount disease. Since 1987, the elastic Blount brace, a medial upright design that uses a wide elastic band just distal to the knee joint ( Fig. 22-11 ), has been used almost exclusively because of its ease of fabrication and smaller profile. With this orthosis, 65% of tibiae had successful outcomes at an average follow-up of 5.9 years. However, corrective osteotomies for one or both extremities were eventually required in 70% of patients with bilateral involvement, as opposed to only 6% of patients with unilateral involvement. All patients were instructed to use the brace during the day (i.e., during weight bearing). Depending on the patient’s physician, some patients were encouraged to use the brace for 20 to 24 hours per day.

Elastic Blount braces. Note the medial upright with a drop-lock knee hinge that can be locked to increase the effectiveness of valgus pressure during weight bearing.

Early brace treatment therefore appears to be effective in stage I or II disease up through 36 months old, especially in those with unilateral involvement. Patients with bilateral involvement may also benefit from orthotic management, but surgical correction is more likely to be needed for one or both extremities. Full-time orthotic treatment (i.e., 23 hours per day) is traditional so that the knee is fully protected during the day when it is maximally exposed to varus forces during weight bearing and so that appropriate valgus force continues to be applied at nighttime during non–weight bearing, although we recognize that part-time wear has been successful as well.

Valgus correction should be increased by bending the medial upright every 2 months until standing radiographs show that at least a neutral mechanical axis has been achieved. Brace wear can then be gradually tapered over a period of several months. To ensure permanent correction, the metaphyseal lesion should start resolving radiographically while the mechanical axis is being corrected, and the lesion should have nearly resolved by the time that the patient is no longer using the orthosis.

Brace therapy is not generally appropriate for children older than 3 years. A maximum trial of 1 year of orthotic treatment to correct the varus deformity is recommended; thus, if correction is not achieved within this time frame in a child younger than 3 years, the orthopaedist can still perform definitive osteotomy before the patient is 4 years old. Good results from this single surgical intervention by this age are seen in almost 90% of cases. To begin orthotic treatment after age 3 means that the outcome of treatment will not be known until the patient is older than 4 years if brace therapy is given an adequate trial of 1 year. Such delay risks postponing corrective osteotomy past the critical age of 4 years, if 1 year of orthotic treatment is not successful. As melodramatic as it may seem, even a few months’ delay in performing surgery by 4 years old can result in failure to achieve permanent reversal of inhibition of the proximal medial physis. For stage III lesions and especially for stage IV lesions, it is debatable whether mechanical realignment with a single osteotomy can ever reverse the physeal inhibition (see Fig. 22-10 ). The association between those older than 5 years and biologic physeal arrest (stages IV and greater) cannot be overemphasized.

Treatment of Langenskiöld Stage II Lesions.

Surgical treatment in the early stages of the disease (stage II) is crucial to achieve permanent and lasting correction and to avoid the sequelae of joint incongruity, limb shortening, and persistent angulation. Patients with stage I or II disease have a significantly lower incidence of repeat osteotomy than do those with stage III disease. Surgical overcorrection of the mechanical axis to at least 5 degrees of valgus by 4 years of age, along with lateral translation of the distal osteotomy fragment, is believed to be optimal. Such overcorrection ensures that the supine correction attained at surgery will be sufficient to translate the mechanical axis into the lateral compartment of the knee once the patient begins bearing weight. Overcorrection of the mechanical axis offsets the tendency of the knee to go back into varus as a result of any sloping of the medial epiphyseal surface and relaxation of the lateral ligaments.

Although correction to within 5 degrees of neutral alignment may prove to be adequate, most authors recommend physiologic valgus or overcorrection. Based on the physeal inhibition phenomenon, overcorrection to absolute valgus alignment is required to reverse the excessive compressive forces medially and allow a Langenskiöld II or III physis not already irreversibly damaged to respond to such mechanical unloading.

The specific type of proximal tibial osteotomy (e.g., dome, closing wedge, or opening wedge) in young children is not important as long as the appropriate valgus and lateral translation are obtained. The level of osteotomy should be just distal to the patellar tendon insertion to avoid the proximal physis and its most distal extent. Internal tibial torsion should be addressed by external rotation of the distal fragment. Fibular osteotomy in the proximal third of the diaphysis should be performed routinely through a separate incision. Because long-leg casts must often be split during the postoperative period, some form of internal fixation (e.g., with Kirschner wires) is helpful in maintaining correction. Prophylactic fasciotomy of the anterior, lateral, and posterior compartments is recommended because of the not insignificant incidence of compartment syndrome. After proximal tibial osteotomy there may be subtle weakness of the extensor hallucis longus despite fasciotomy. This weakness, which is frequently overlooked, is probably due to partial peroneal nerve palsy.

The concept of “guided growth” using extraperiosteal nonlocking plates may prove to be an attractive alternative to conventional acute corrective osteotomy in young patients (younger than age 4) with Stage I and II disease. The technique relies upon the tension band principle as opposed to physeal compression, and observed rates of correction are equivalent and possibly more rapid than stapling with compar­able effectiveness in desired normalization of mechanical axis. While our institution lacks experience applying this technique to treat infantile tibia vara, an 89% success rate of mechanical alignment attainment in this population (average age 4.8) has been reported. Currently no long-term outcome data exist to answer whether or not rebound deformity occurs following this minimally invasive technique and warrants further investigation before definitive recommendation.

Treatment of Langenskiöld Stage III Lesions.

Stage III lesions can respond to corrective osteotomy alone in patients older than 4 years. However, the longer the delay in surgery after 4 years old, the greater the risk for recurrence, which is not uncommon with stage III lesions (see Fig. 22-10 ). Thus, because of the worsening prognosis, neither observation nor orthotic treatment is recommended beyond this age, especially if the deformity exceeds 10 degrees of femorotibial varus.

Treatment of Langenskiöld Stages IV/V Lesions.

Lesions greater than stage III cannot be definitively corrected by simple mechanical realignment because physiologic physeal arrest has already occurred by stage IV ( Fig. 22-12 ). Even though no bony bridge can be visualized by tomographic methods in stage IV or V lesions, physeal damage has progressed to the point where stages IV and V lesions effectively act as medial physeal arrests.

A, Radiographs of a 6-year, 5-month-old girl showing a stage IV lesion on the left and mild varus residual on the right. B, Radiographic appearance after bilateral upper tibial osteotomies. The mechanical axis is overcorrected to 12 degrees valgus on the left. The distal fragment has not been lateralized, so the effectiveness of this overcorrection is diminished. C, Radiographic appearance 3 years postoperatively. A stage VI growth arrest has resulted on the left.

Because stage IV lesions can be seen in children as young as 6 years, their treatment presents a significant problem in management. Repeated osteotomies, required because of the predictable and certain recurrence of deformity, may help prevent intraarticular deformity but do not address limb shortening and, because of the repeated neurovascular risk, are clearly an unattractive approach.

Alternatively, some form of lateral epiphysiodesis—permanent or transient—will prevent recurrence by eliminating growth from the lateral side of the proximal tibial physis but will obviously result in significant limb length discrepancy when performed in such a young patient. Total physeal closure at the time of osteotomy prevents recurrence but, by producing unacceptable shortening in young patients, predictably commits them to subsequent limb-lengthening procedures.

Thus, treatment must be carefully individualized for stage IV or greater lesions in patients younger than 10 years with at least 2 years of growth remaining. Realignment combined with medial epiphysiolysis and the use of interposition material to prevent rebridging is the treatment of choice for these patients. The medial physis at this stage is so damaged that it will inevitably progress to a fully ossified physeal bridge (stage VI) (see Fig. 22-12 ). Epiphysiolysis can restore symmetric growth of the proximal end of the tibia and prevent retethering medially, thereby reducing the likelihood of recurrent deformity or disruption of the articular surface. A review of 24 patients undergoing this treatment for stage IV or greater infantile tibia vara at our institution demonstrated that the procedure was valuable in gaining meaningful growth. Eighty percent of children operated on at younger than 7 years gained enough growth that they required only angular correction (by osteotomy or hemiepiphysiodesis), if indeed they needed any further treatment at all ( Fig. 22-13 ). Adequate valgus alignment beyond a 0-degree femorotibial angle after epiphysiolysis and osteotomy was also important in the success of the procedure. In patients older than 7 years, epiphysiolysis was effective in fewer than 50% of cases, thus suggesting that alternative methods of treatment should be considered.

A and B, Clinical and radiographic appearance of a 6-year-old girl with a neglected deformity (stage IV-V). Simple osteotomy in such a case is associated with a 100% incidence of recurrence. C, Radiographic appearance after physeal resection with a Cranioplast interposition graft to prevent rebridging. Pins in the epiphysis anchor the interposed material. A corrective osteotomy to neutral mechanical axis was also performed. D, Radiographic appearance 6 years later. The deformity has remained corrected, with growth evident medially. The tibia on the right is 2 cm shorter than on the left. The patient is skeletally mature. E, Clinical appearance at 13 years old. The patient is asymptomatic.

Technique.

Preoperative assessment by MRI is essential to determine the amount of abnormal physis in three dimensions ( Fig. 22-14 ; see Fig. 22-6 , A to C ). A curved skin incision allowing access proximal to the mid-medial joint line and metaphysis distal to the level of the tibial tubercle anteriorly is made so that the epiphysiolysis and a corrective high tibial osteotomy can be performed through the same incision. A separate longitudinal incision is made over the proximal end of the fibula for performance of a fibular osteotomy.

A and B, Preoperative plain radiograph and corresponding MRI with a line marking the area of planned metaphyseal resection. C, Intraoperative fluoroscopic image showing the path of the curved osteotome. D, Radiograph following resection of the metaphyseal “beak” and careful curettage of the physis. E, Resection was continued laterally until the epiphyseal bone, physis, and metaphyseal bone were uncovered. The Cobb is elevating the joint surface under the medial meniscus. F, Fluoroscopic shot after corrective osteotomy performed below the tibial tubercle. A fibular segment was resected at the same level. Note the Bovie cord was used to assess the mechanical axis intraoperatively. G and H, Another case example to illustrate the Cranioplast interposition material pinned to the epiphysis. Subsequent follow-up showed persistent growth disturbance noted by the asymmetric Harris growth lines. In retrospect, the metaphyseal-physeal resection may not have extended far enough laterally.

The pes anserine tendons are sharply elevated in an anterior-to-posterior direction to expose the drooping epiphyseal-metaphyseal junction. A curved osteotome is placed in the cleft between the “beak” of the epimetaphysis and the normal metaphysis. Under fluoroscopic control, the osteotome is advanced in a semicircular path proximally and posteriorly to resect the fibrocartilaginous “beak,” with exit just distal to the medial tibial plateau surface (see Fig. 22-14, C ). This mass of abnormal fibrocartilage lies just under the weight-bearing surface of the medial aspect of the tibia; once it is removed, the true physis can be identified by direct vision and fluoroscopy. A dental burr or small curets are used to further undercut and visualize the normal physis from the metaphyseal side so that any remaining abnormal metaphysis can be completely removed (see Fig. 22-14, D and E ). The defects in the metaphysis and epiphysis supporting the articular surface are then filled with an interposition material, which also covers the medial physis. We prefer Cranioplast because it can be molded in the putty state to a precise fit within the metaphyseal beak, thereby covering all raw bone surfaces securely. It can be anchored to the epiphysis via small Steinmann pins so that the cement will not migrate distally with growth (see Fig. 22-14, G ). The Cranioplast/pin construct also supports the medial tibial joint surface. Technical inadequacy of the metaphyseal and physeal resection—that is, the resection does not proceed far enough laterally to remove all abnormal metaphyseal bone and the presumed abnormal physis immediately adjacent to it—probably plays an important role in eventual failure of the untethering of subsequent growth (see Fig. 22-14, H ).

After hardening of the polymethyl methacrylate, a closing wedge/lateral displacement osteotomy of the proximal end of the tibia just distal to the tibial tubercle is performed (see Fig. 22-14, F ). The osteotomy should be internally fixed, usually with one or more pins, in case proximal control by cast immobilization is compromised by the not infrequent need for cast splitting or partial removal because of neurovascular concerns. Slight overcorrection into valgus alignment is mandatory, primarily to ensure transfer of the mechanical axis into the lateral compartment of the knee. This technique is especially important in knees where long-standing lateral joint laxity may not be apparent until the patient resumes the weight-bearing position or where a small component of joint obliquity encourages recurrent varus. Inadequate valgus alignment after epiphysiolysis is implicated in failure of the procedure.

The extremity is usually placed in a cast for 8 weeks to ensure healing of the osteotomy before any weight bearing. Full weight bearing is then gradually allowed after the patient regains active knee range of motion while non–weight bearing.

Treatment of Langenskiöld Stage VI Lesions.

Treatment of stage VI lesions with established bony bridges must also be individualized. Factors to be considered are patient age, the amount of skeletal growth remaining, and the degree of deformity of the joint surface. If the patient has less than 2 years of growth remaining and a relatively normal joint surface, corrective osteotomy with complete physeal closure is a practical means of obtaining and maintaining correction. The osteotomy can be made through the physis so that the mechanical correction is placed as close to the joint as possible and permanent physeal closure occurs.

As previously mentioned, resection of the bony bridge with placement of interposition material is appropriate in patients younger than 7 years. Unfortunately, a patient with a stage VI lesion will probably be older than this age limit, when epiphysiolysis is less predictable. Treatment options in patients with more than 2 years’ growth remaining include completion of the lateral tibial epiphysiodesis, angular correction, and lengthening, if indicated, usually during the same treatment session. In patients requiring limb length equalization with or without correction of deformity, correction by external fixation and distraction osteogenesis is an effective and invaluable method for salvaging a potentially unsatisfactory extremity. Breaking of a physeal bridge by asymmetric physeal distraction has been described as an alternative approach to resection of the bony bridge in children near skeletal maturity.

In children older than 10 years, the deformity in recurrent or neglected advanced-stage lesions may be so significant that medial plateau elevation by intraarticular osteotomy, along with mechanical axis correction, may be indicated We recommend careful preoperative evaluation of potential joint incongruity as suggested by plain radiographs and confirmation with an MRI because the “true” articular surface may be maintained by cartilage (see Fig. 22-6, A to C ). Intraoperative assessment of the joint line with arthrography (see Fig. 22-8 ) may also assist in identifying which patients may benefit from intraarticular osteotomy to improve joint congruity. Fluoroscopic varus and valgus stress views can demonstrate significant joint instability as a result of “true” joint surface depression. By elevating the medial plateau with the knee in maximal valgus alignment, the instability of the medial compartment during weight bearing is theoretically relieved ( Fig. 22-15 ). Therefore, restoration of joint congruity and removal of varus instability provide rationale for this treatment. Remember that the intraarticular osteotomy represents one component of the procedure and that a separate proximal tibia osteotomy is required to correct the mechanical axis, the so-called double level osteotomy. ( Fig. 22-16 ). The realignment component can be achieved acutely or gradually, which has the advantage of concurrent deformity correction and lengthening because completion of the lateral proximal tibia and fibula epiphysiodesis is also performed.

A and B, Schematic correction of the medial joint line depression by an intraarticular osteotomy to elevate medial plateau, combined with angular correction of tibia vara. C, Sloping of the medial plateau in severe Blount disease. D, The extent of instability and the amount of desired plateau elevation are estimated from varus–valgus stress fluoroscopy.

Medial plateau elevation technique. A, A series of anterior-to-posterior drill holes are made to outline the path of the osteotomy. B and C, The drill holes are connected by a curved osteotome, with the medial plateau segment gradually hinged upward. D, Provisional stabilization of the elevated segment is accomplished with the knee in maximum valgus stress. E and F, The medial plateau is stabilized and buttressed with appropriate internal fixation and bone grafting of the defect created under the plateau.

(Courtesy J Eric Gordon, MD.)

Although the plateau elevation procedure has been performed for more than 20 years, long-term outcome studies are not available. Short-term results are generally encouraging with a reported decrease in pain and instability, satisfactory healing, and reconstitution of the tibial plateau. The ability of the proposed procedure to maintain joint congruity and mechanical alignment over time and prevent early medial compartment degenerative disease, characteristic of stage VI deformity, remains to be proven. Furthermore, no comparative studies of single proximal and double level tibia osteotomies exist. The intraarticular osteotomy must be considered a final salvage procedure in older patients with severe joint deformity secondary to inadequate early treatment of infantile tibia vara.

Complications of Surgery.

Complications of proximal tibial osteotomy in a growing child can be numerous. The osteotomy must be performed distal to the tibial tubercle to avoid growth arrest. Injury to the proximal tibial physis at the level of the tibial tubercle produces proximal tibial recurvatum, with resulting hyperextension instability of the knee. The optimal site of the osteotomy, distal to the tubercle, is near the level of the trifurcation of the popliteal artery. The anterior tibial artery, which passes through the interosseous membrane and enters the anterior compartment, can be injured in as many as 29% of oste­otomy procedures. Prophylactic fasciotomy of all the compartments should be performed during all osteotomy procedures, with appropriate postoperative neurovascular surveillance for the first 48 hours. Other reported complications include peroneal nerve palsy, deep and superficial infections, iatrogenic fractures, and loss of correction. ^†

† References .

Summary.

As can be readily discerned from the complex treatment options and numerous complications discussed under the treatment of Langenskiöld stages IV to VI lesions and the risks involved in general for any osteotomy or repeat procedure, early treatment aimed at curing infantile tibia vara is far more attractive and more likely to produce a good outcome than later treatment of the more advanced condition. Early diagnosis plus corrective treatment (orthotic or osteotomy) by 4 years old is the most reliable way to avoid a poor outcome in both joint and leg function and cannot be overemphasized.

Osteotomy.

High tibial osteotomy is the standard and most direct method to correct adolescent tibia vara. Correction to a neutral mechanical axis is sufficient to restore growth from the medial physis and thus prevent recurrence, although premature closure of the entire physis has been observed after high tibial osteotomy (see Fig. 22-17 ). Overcorrection in adolescent tibia vara is contraindicated, as opposed to the recommended intentional overcorrection into valgus for infantile tibia vara.

There is an interesting dilemma when contemplating correction of the mechanical axis in these patients, in that correction to a neutral mechanical axis in patients with morbidly obese thighs actually produces an unsightly cosmetic result that appears to be excessive valgus. In addition, when these patients undergo correction to neutral alignment, they may have difficulty ambulating because their thighs impinge during normal gait after mechanical realignment (see Fig. 22-17, G and H ). Although undercorrection may invite recurrence of the deformity, it has been our observation that a final femorotibial angle of 0 to 5 degrees varus is probably the best compromise between the mechanical correction desired and the problem posed by the massive proximal thigh girth.

Valgus-producing high tibial osteotomy with rigid internal fixation for acute correction of the mechanical malalignment is probably the most commonly used approach. Again, because of the massive thigh girth, external immobilization with casts is not effective in maintaining alignment of the osteotomy, and rigid internal fixation is far superior. The obvious challenge with this approach is that correct alignment must be achieved at surgery because it cannot be changed postoperatively without reoperation. Loss of fixation and inappropriate intraoperative alignment are causes of postoperative undercorrection or overcorrection. In addition, the well-known complications of high tibial osteotomy (e.g., nerve palsy, compartment syndrome, infection, delayed union or malunion, and in this patient population, the possibility of deep vein thrombosis) make acute correction a formidable surgical task. Special large-circumference tourniquets are required for intraoperative hemostasis, and the logistics of performing high tibial osteotomy in a very obese patient must be taken into account before bringing such a patient into a pediatric operating room.

Emphasis on recognition and treatment of distal femoral varus has added a further dimension of complexity to treatment of adolescent tibia vara. Femoral varus of more than 5 degrees beyond the normal femoral mechanical axis (lateral distal femoral angle >93 degrees) has been reported in more than 50% of patients, with 19% having deformities of more than 10 degrees of varus. Distal femoral varus was corrected acutely in two thirds of limbs undergoing simultaneous proximal tibial osteotomy with correction by external fixation, the indication being mechanical femoral varus greater than 5 degrees beyond normal. The rationale for correction by external fixation (see “Realignment by External Fixation”) is the adjustability of the postoperative limb position to avoid malcorrection in these obese patients, in whom intraoperative control of alignment is challenging. Pain-free and clinically stable knees were reflective of the short-term results studying this comprehensive approach, but avoidance of early degenerative joint disease remains unproven. Because there are no reports comparing these results with proximal tibia osteotomy alone, the value of the additional levels of correction remains uncertain.

Realignment by External Fixation.

The problem of achieving the desired alignment intraoperatively in this patient population is more challenging than is often acknowledged, and the inability to postoperatively adjust internal fixation is a significant disadvantage. In addition, limb length inequality may exist in unilateral cases, and the ability to achieve equalization by lengthening after angular realignment makes external fixation all the more attractive. A direct retrospective comparison of acute versus gradual correction in a small series of patients using external fixation suggested a higher frequency of accurate angulation and mechanical axis correction with the gradual approach, but the clinical relevance of such small differences in radiographic measurements is unclear. The major disadvantages of external fixation are pin or wire complications, which can produce loosening, sepsis, or nerve palsy; and joint stiffness and muscle weakness, which can complicate prolonged treatments. Because the total treatment time with external fixation is definitely longer than the 6 to 8 weeks until union by conventional osteotomy, these disadvantages may have a significant effect on the ultimate outcome.

Three methods of external fixation have been reported. (1) External fixation can be used to align an extremity acutely after complete tibial and fibular osteotomy. (2) Alternatively, a corticotomy technique with gradual correction (distraction osteogenesis) can be performed with either circular or monolateral external fixators ( Fig. 22-18 ). ^‡ (3) Hemichondrodiastasis, or asymmetric physeal distraction, has also been used, with mixed results, depending on the rapidity and strength of bony consolidation in the physeal distraction gap. Because of the almost certain physeal closure after physeal distraction methods, use of asym­metric physeal distraction is limited to patients nearing skeletal maturity. The time to consolidation with physeal distraction can be prolonged, and thus this approach appears to offer little advantage over conventional metaphyseal corticotomy.

A and B, Clinical and radiographic appearance of a 13-year-old with adolescent tibia vara. There is a 2-cm shortening on the left. C, Radiograph obtained after gradual correction by external fixation. The regenerated bone was allowed to consolidate. Total time in the frame was 14 weeks. D, Final result after frame removal.

‡ References .

Although correction by external fixation has the advantage of postoperative adjustability, the technique is just as formidable as traditional osteotomy. Gradual deformity correction carries a different set of problems related to maintaining function and tolerating longer treatment periods with potential fixation and pin complications.

Lateral Epiphysiodesis.

Because of the potential complications associated with proximal tibial osteotomy and either acute or gradual correction, correction by lateral proximal tibial epiphysiodesis is an attractive alternative procedure. The technique is significantly simpler and associated with minimal morbidity, the only real complication being that angular correction is at times not realized. Assuming that the epiphysiodesis is technically adequate, incomplete or inadequate correction may be due to a medial physis that is simply too suppressed to respond to the tethering effect of the lateral epiphysiodesis. The main disadvantage of lateral epiphysiodesis is that rotational deformity cannot be addressed.

Patients treated with this technique have a 50% to 87% response rate in which correction of the varus malalignment is judged to be satisfactory at maturity and no further treatment is necessary ( Fig. 22-19 ). Our institution reported a failure rate, defined by need for osteotomy or mechanical axis deviation exceeding 40 mm, of 66% following lateral hemiepiphysiodesis. Factors associated with a higher risk of failure included an age older than 14, BMI greater than 45 kg/m ² , and more severe varus deformity. While variable amounts of correction can be expected, performing a lateral epiphysiodesis in no way complicates subsequent correction by high tibial osteotomy and remains a viable option for initial treatment, particularly in younger patients with mild-moderate deformity. Surgical decision making should weigh the benefits of a less morbid procedure against a more extensive but predictable realignment achieved with an osteotomy.

A, Radiographic appearance of a 13½-year-old boy with adolescent tibia vara on the left. Only the medial fourth of the proximal physis appears widened. Excessive physiologic genu valgum is present on the right. B, “Windswept” clinical appearance of the combination of deformities. C, Fluoroscopic view of lateral proximal tibial epiphysiodesis performed via a miniincision. The peripheral fourth of the physis is treated by curettage (depth, 1.5 cm). D, Clinical appearance 1 year after left lateral tibial and right medial distal femoral epiphysiodesis.

A lateral epiphysiodesis can be performed either as an open procedure or percutaneously ( Fig. 22-20 ). The percutaneous technique probably has a higher rate of failure because of technical inadequacy of the actual curettage of the physis. In addition, the main advantage of the percutaneous technique, cosmesis, may not be a critical factor in treatment of this patient population. We have found that an open epiphysiodesis performed through a miniincision under fluoroscopic control is reliable in terms of ensuring that the lateral physis is obliterated by curettage under direct vision. A local bone graft from the metaphysis and epiphysis immediately adjacent to the physis is packed into the physeal excavation. In selected patients, a distal lateral femoral epiphysiodesis can also be performed if there is radiographic evidence of distal femoral varus. We have not performed proximal fibular epiphysiodesis as part of the treatment of adolescent tibia vara in the 13- to 15-year-old patient population. A significant difference in fibular overgrowth was reported when proximal tibia epiphysiodesis was performed alone compared with combined fibular epiphysiodesis and controls, with an estimated rate of 3 mm/yr reported from one institution. Unless expected overgrowth exceeds 2 cm, benefits of this added procedure are unlikely because symptomatic fibular overgrowth is not anticipated.

Cavitation of the peripheral physis, including metaphyseal and epiphyseal extension, to ensure adequate ablation for epiphysiodesis.

Hemiepiphyseal Stapling.

Lateral hemiepiphysiodesis of the proximal end of the tibia (and distal end of the femur) can also be produced by insertion of Vitallium staples spanning the physis. This procedure, introduced by Blount and Clarke in 1949, theoretically creates the possibility of a transient hemiepiphysiodesis and should be used in younger patients in whom eventual removal is planned when the deformity has corrected, or slightly overcorrected, and growth remains. Stapling can be effective in patients with late-onset tibia vara with mild to moderate deformity and a chronologic age of 12 years or younger. In this setting, 27 of 29 patients obtained a successful or partially successful outcome from stapling, with minimal morbidity from the procedure itself or from a second procedure to remove or revise staples, required in approximately a third of patients. Severe preoperative varus (zone 4 medial mechanical axis deviation in the Mielke-Stevens classification ) and older adolescents with less growth remaining will not benefit from stapling, just as a permanent hemiepiphysiodesis by curettage might also be ineffective.

The timing of the stapling procedure is not as crucial in avoiding overcorrection as it may be in permanent hemiepiphysiodesis, although patient compliance with follow-up is mandatory with either procedure. We have observed that most patients with adolescent tibia vara have advanced bone age, and thus there is a lessened risk for valgus overcorrection with permanent hemiepiphysiodesis in patients older than 11 years. Stapling has its greatest indication in patients younger than 11, in whom valgus overcorrection is a distinct possibility with any form of hemiepiphysiodesis, including stapling, and thus the transient method with appropriate follow-up is more useful.

Hemiepiphyseal Plating.

The advent of extraperiosteal plate and screw systems introduced an alternative method to nonpermanent deformity correction in patients with open physes ( Fig. 22-21 ). The technique employs a tension-band concept as opposed to the physeal-compressive effect exerted by stapling and has proven to be equally effective in restoring mechanical alignment. However, awareness of potential technical pitfalls when using these devices is essential as more mechanical failures have been reported in obese patients characteristic of adolescent tibia vara (see Fig. 22-21 ). The intersection of the screw shank at the lateral cortex in the metaphyseal region accounted for the failures in nearly all cases. Biomechanical testing of different guided growth constructs suggests fatigue strength is superior for solid compared with cannulated screws with stainless steel screws yielding the highest number of cycles to failure. When using extraperiosteal plating in this high-risk population, consider adding a second parallel plate or a single four-hole plate, noncannulated screws, and possibly stainless steel implants to avoid potential screw breakage and the need for revision surgery.

Case example of guided growth using 8-plates and failure. A, A 10-year-old male with adolescent tibia vara. B, A lateral “8 plate” was implanted to tether the proximal lateral tibial physis. C, Nine months later, minimal correction of the tibia vara is noted, along with a broken distal screw. D, Close-up of broken implant. E, Revision age 11. F, Final result following plate removal.