The majority of children with arthrogryposis multiplex congenita (AMC) have lower extremity involvement. Although there are typical patterns of presentation, variability of deformity combinations seems unlimited, including asymmetric involvement. The classic arthrogrypotic hip contracture is flexed, abducted and externally rotated, with a subgroup of children with hip extension contractures. AMC hips dislocate much earlier in pregnancy and are therefore more proximally displaced and stiffer than idiopathic dislocations. Knee contractures can either be in flexion or extension, with a lack of motion causing added treatment difficulty. Foot deformities include the clubfoot and its variants, and the congenital vertical talus (CVT), which have all seen a recent paradigm shift in treatment.
Although not all adults with AMC are ambulatory, those who do walk work hard to remain so. The philosophy of treating children is gradually changing toward achieving each child’s individual potential to become more functional, independent, and ambulatory. This article synopsizes the treatment strategies presented in September 2014 in Saint Petersburg, Russia at the second international symposium on arthrogryposis. It will discuss different procedures to approach the constellation of lower extremity deformities in AMC, and strategies of timing of the procedures and treatments to effect the best outcomes, without over treating a patient past their potential.
OVERALL GOALS AND STRATEGIES OF TREATMENT FOR THE LOWER EXTREMITIES
Arthrogryposis is a heterogenous spectrum of conditions with >400 different causes, making all-encompassing statements on treatment difficult. However, the general aim should be to optimize hip, knee, and ankle positioning for sitting, standing, and walking when the child is fully grown, while importantly preserving muscle strength.
Sometimes the first encounter with an orthopaedic surgeon follows an ultrasound discovery of a fetus with malpositioned joints and a scarcity of movements. In these cases, it is advised to not let the fetus be born overdue, as early free movement is advantageous for muscle formation and joint mobility. After birth, stiff and malaligned joints should be gently mobilized, modifying retaining splints as the range of motion improves. Early after birth the connective tissues are very compliant, and the noncalcified cartilaginous joints are elastic, so early manipulations may almost normalize some joint and ligament configurations. The hyperextended and dislocated knees are a good example, where very early manipulations often alleviates any need for surgery. When hyperextended knees present with congenital foot deformities, they can be treated early with simultaneous serial casting. Later, the child’s normal urge to sit, stand, and walk is supported, with the help of ankle-foot orthoses (AFOs), knee-ankle-foot orthoses, or hip-knee-ankle-foot orthoses, as appropriate. By using the usually strong core muscles, the child will learn to find their center of gravity. Balanced standing and walking, with the help of custom molded orthotics, will reduce the need for crutches.
Open reduction of dislocated hips should be performed after correction of the feet, and in any case before the age of 3. Hip contractures are best treated during the same timeframe, with a reorientational osteotomy of the proximal femur for severe contractures, and fascial releases for more minor ones. This could minimize the need for tenotomies around the hip, maintaining all the muscle strength available.
Knee flexion contractures may be the last deformity corrected. Guided growth may be used for mild deformities. Alternatives are serial casting or posterior releases followed by slow extension with an external fixator. Clubfoot relapses will often occur during the growth years and may be treated by repeated serial casting. Such casting is more beneficial for the child, as extensive surgery increases the risk for future osteoarthritis and pain. If casting is unsuccessful, a posterior release might be needed, but talectomy should be avoided.1 Fibrotic and malfunctioning muscle will have a disordering effect on the physes and joints, resulting in recurrence of the malformed joints. The use of splints can help to counteract these forces by keeping the joints in a functional position. It is therefore strongly advised that orthotics be used throughout childhood and adolescence.
HIP DISLOCATIONS AND CONTRACTURES
Hip involvement in AMC occurs in 56% to 90% of patients, either as hip dislocations (15% to 30%) or hip contractures (18% to 51%). Correcting these deformities improves the chances of achieving independent ambulatory status, and/or continued functional ambulation as an adult.
These teratologic dislocations occur much earlier in gestation than idiopathic hip dislocations, and are therefore stiffer with higher displacement. Nonsurgical methods of relocation (eg, Pavlik harness) have proven to be ineffective. Historically, strong arguments were made against performing open reductions of arthrogrypotic hips out of concern of resulting hips becoming stiff and painful. But 2 studies have shown that in cases of unilateral dislocations, the flexion-extension total arc of motion of the dislocated hip is only 12 to 20 degrees2 less than the contralateral side, both before and after relocation. When comparing preoperative to follow-up range of motion of a dislocated hip, the flexion-extension total arc of motion only decreased by 8 degrees on an average. In a study of 14 patients with 5 to 23 years follow-up after hip reduction, 11 were community and 3 were household ambulators.
Strategies on the timing and extent of surgery for hip dislocations differ with the authors:
- Open reduction between 3 and 6 months of age, none of the patients requiring femoral shortening.
- Reduction via the anteriolateral approach, either as reduction alone for age 6 to 20 months, or supplemented with femoral osteotomies (shortening, derotation, varus) and pelvic osteotomies for ages 2 to 6 years (Fig. 1).
- Reduction via the anteriolateral approach for ages 10 to 38 months, each including a femoral derotation-varus and/or shortening osteotomy, and 18 of 22 having pelvic osteotomies (Fig. 2); or
- Reduction via the medial approach for ages 10 to 40 months with femoral shortening osteotomies in 22 of 33 hips.
The anteriolateral approach is a more direct exposure, and has accessibility for pelvic osteotomies if needed, but often has higher blood loss and possibly an ancedotal association with heterotopic bone formation. The medial approach tends to have less blood loss, with a cosmetic scar, but has a higher risk of neurovascular traction injury. Two methods to supplement the stability of the reduction were described, one used the ligamentum teres to tether the femoral head to the acetabulum,3 and the other was a temporary fixation pin across the femoral-acetabular joint.4 Despite preoperative radiographic appearances, there is nearly always an appropriately sized acetabulum present. A hip spica cast is used for about 6 weeks, with possible removal in the operating room to allow for evaluation of the hips under anesthesia. Some authors used a hip abduction brace for a variable amount of time thereafter. Complications included redislocation, stiffness, and an avascular necrosis rate up to 19% in 1 series, the majority in patients over 3 years of age at surgery. Therefore, treatment before 3 years of age is optimal.
Isolated hip flexion contractures may respond to a percutaneous anterior hip release. The contracted conjoin tendon of the sartorius and the tensor fascia lata are released below the anterior superior iliac spine through a “stab” incision. The fascia lata is further incised laterally to just superior to the greater trochanter. The rectus femoris and the lateral fascia overlying the ileopsoas muscle may be carefully incised if necessary. A Petrie cast is used for 4 to 6 weeks, with prone lying to help with hip stretching. Any remaining flexion contracture may continue to improve with aggressive physical therapy.
The typical arthrogryposis hip contracture is multiplanar, in abduction, flexion, and external rotation. A proximal femoral reoreintational osteotomy addresses all the deformities at a single level with a posterior-medially based wedge-shaped intratrochanteric osteotomy, acutely derotating the limb.5 With the hip in its usual resting position, a proximal osteotomy is made parallel to the transverse plain of the pelvis, and a second osteotomy is made perpendicular to the shaft of the femur, removing the wedge of bone. This leaves the hip joint in its original position but realigns the leg with the body. Fixation is attained with a 90-degree angled cannulated blade plate (Fig. 3); a Petrie cast is used for 6 weeks, to allow for osteotomy healing and prone positioning for hip flexor stretching. At an average 40-month follow-up after the procedure, 36 of 65 patients with severe hip contractures walked independently, and another 20 walked with walkers.
Knee contractures, whether in flexion or in extension, limit activities. Unopposed, spastic or fibrotic quadriceps during gestation will lead to extension contractures. In severe cases the tibia will dislocate anteriorly and proximally. If treated just after birth, when muscle, tendon and cartilaginous tissues are soft and pliable, the dislocation and flexion deficit can in some cases be overcome without surgery. The knee is reduced similarly to how a dislocated finger joint is reduced, by first distracting the joint, and then flexing the knee while simultaneously translating the proximal tibia articular surface posteriorly with respect to the femoral condyles.6 The limb is then casted in the maximally flexed position. By having the parents extend the hip while stabilizing the pelvis, the short and stiff rectus femoris muscle can be stretched further between weekly castings. If progress is limited, a lateral radiograph of the knee will determine if a pseudocorrection is occurring through an iatrogenic anterior bow of the tibia, due to a too stiff knee. If so, surgery is needed, with lengthening or percutaneous tenotomy of the rectus tendon (Fig. 4). If sufficient flexion is not achieved, the skin incision is expanded and a quadricepsplasty with a V-Y-plasty of the rectus tendon is performed.7 For sitting 90 degrees of flexion is ideal, but for bicycling 110 degrees of flexion is needed. A theoretical concern of performing a quadriceps lengthening is that it will lead to knee extension weakness, so some practitioners favor waiting until after 10 years of age and performing a Judet quadricepsplasty, elevating of the quadriceps from the femur, and transecting the muscular fascia.8
Flexion contractures are more common than extension contractures, and may make walking difficult. For optimal ambulation, the knees should have <15 degrees extension deficit. With this aim in mind, a child born with flexion contractures should as early as possible be treated with manipulations and splinting in maximal extension. If the flexion contractures are very stiff, serial casting could be tried. Surgical treatment of flexion contractures is performed as early as 3 years of age by some, whereas others wait until after 4 years for the larger anatomy and better cooperation with postoperative therapies.
Flexion contractures can be loosely categorized as mild (<30 degrees), moderate (30 to 50 or 60 degrees), and severe (>50 or 60 degrees). Mild contractures can be treated by serial casting, or by temporary anterior hemiepiphysiodesis of the distal femoral physis.9 Using fluoroscopy with a true lateral view, 2-hole plates are placed over the physis medial and lateral to the patella, ensuring no impingement or soft tissue tethering. Moderate and severe contractures often benefit from posterior knee releases as an adjunct procedure, either through a standard posterior incision, or through medial and lateral longitudinal incisions.10 Posterior releases usually do not increase knee extension by >10 to 20 degrees, but are permissive to further correction with either serial casting or anterior distal femoral hemiepiphysiodess, for moderate contractures, or gradual joint distraction with an external frame (Ilizarov) for severe contractures.10 With a frame, the knee could be gradually extended 1 to 2 degrees per day. It is important to align the knee hinges with the knee center of rotation, essentially along a line between the medial and lateral epicondyles. The acquired full correction is maintained in the frame for an additional 4 weeks. When the frame is removed, the leg is casted in extension for 4 weeks, where weight-bearing is allowed in the cast, then transitioned to a knee-ankle-foot orthoses. Light-weight orthotics are most often needed the whole life, and should be fine-tuned to each individual’s special need for stability, mobility, and power loading.
Obviously, when the physes are closed, guided growth cannot be performed. Although extension osteotomies are shown to result in a recurrence of the flexion deformity with 1 degree per month if the physes are open, the procedure has its place in the skeletally mature patient.11 The extension osteotomies could be fixed either with an external fixator, or with a plate.
Foot deformities occur in 80% to 90% of children with AMC, and can be classified as the classic clubfoot, the equinocavus clubfoot variant, and the CVT. Treatment of these deformities has changed significantly in the past 2 decades, with an emphasis on deformity correction by casting and limited surgeries.
The goal of treatment for these severe, rigid, and relapsing deformities was defined by Lloyd-Roberts and Lettin in 1970: “conversion of a deformed rigid foot into a rigid plantigrade platform”12 to which we add “with as few surgical procedures as possible,” ultimately resulting in a painless, plantigrade foot that can be readily shoed or braced. What makes the arthrogrypotic clubfoot so challenging is the high recurrence rate, regardless of how correction is obtain (surgery or casting), probably related to both inherent muscular imbalances and residual growth. Relapses become less frequent as the child ages, and rarely occur after skeletal maturity. Historically, treatment of arthrogrypotic clubfeet was wholly surgical, usually an aggressive posterior medial release. But the recurrence rate was on an average 73%, and secondary procedures would become incrementally more ablative, including decancellations of individual tarsal bones, talectomies, osteotomies, and fusions.13 Unfortunately, these procedures often did not prevent further deformity in the growing child, and after several operations the foot was short, painful, and deformed. Talectomies, in particular, are associated with lack of forefoot correction, clubfoot relapse, and calcaneotibial arthrodesis in rigid equinus. Large series report the long-term satisfaction rate between 45% and 50% even for primary talectomies.1,14–16
The Ponseti method of serial casting has been modified by several practitioners to treat nonidiopathic clubfeet, including to treat children of older ages (Fig. 5). The standard technique relies on a series of cast moldings to gradually abduct the forefoot relative to the talus, thereby realigning the talonavicular joint and indirectly correcting heel varus. A percutaneous Achilles tenotomy (PAT) is required in the majority of cases at the end of treatment to achieve full correction. Modifications to this technique specifically for the arthrogrypotic clubfoot include a PAT either initially or early in treatment for feet with severe equinus (∼40 degrees) to unlock the talus from the posterior tibia and allow further correction; a second tenotomy is often required at the end of cast treatment to correct the residual equinus. AMC clubfeet rarely dorsiflex as fully as idiopathic clubfeet directly after a PAT, and occasionally a limited posterior ankle release or continued serial casting is required to achieve dorsiflexion above neutral.17 In severe cases, initial treatment may require up to 20 casts and 2 Achilles tenotomies, although <10 casts and 1 tenotomy is the norm. Once corrected, full-time bracing is necessary for the growing child after clubfoot correction. The standard Ponseti foot abduction brace is difficult to apply to children with hip and knee contractures, and children with AMC are unable to kick their feet, a necessary function to prevent recurrent equinus with the foot abduction brace. Most practitioners used custom molded AFOs with correction of heel varus and forefoot adductus; many use nighttime dorsiflexion straps for Achilles stretching. A spring-loaded abduction-dorsiflexion mechanism brace has also had good early results as a nighttime brace. Bracing is often necessary for the duration of childhood to prevent growth-related relapses, as well as stable weight-bearing.
To treat relapsed AMC clubfeet, recommendations include repeated series of castings, soft tissue releases, or decancellations of tarsal bones. Talectomies lead to secondary deformities and tibiocalcaneal fusions, and are rarely indicated.
In older children with severe neglected deformities or previous surgeries, gradual correction may be required with a circular external fixator. This can be done as purely soft tissue distraction, or the frame can be applied after soft tissue releases or osteotomies.
In circumstances and/or regions with limited medical services or lack of follow-up care, a single-step complete correction surgery has been described for children over 3 years of age. A comprehensive soft tissue release is followed by resection of a 3-dimensional midfoot bone wedge designed to align the forefoot with the hindfoot (Fig. 6).
Equinocavus Clubfoot Variant
Equinus and complete midfoot cavus are the major deformities; heel varus, forefoot supination, and adductus are mild or absent. Often a midfoot crease traverses the entire sole of the foot, and toe flexion contractures are usually present. The deformity is very similar to the “atypical” or “complex” type of idiopathic clubfoot, occasionally including the apparently foreshortened great toe. Casting is performed in a manner similar to that of the atypical clubfoot as well, using the thumbs of both hands to dorsiflex the metatarsal heads, with counterpressure of the index and forefingers on the dorsum of the midfoot to correct the cavus. Forefoot abduction is avoided, to prevent development of an ugly equinovalgus/abducted foot. Achilles tenotomies should be delayed until the cavus is fully corrected. This type of clubfoot seems less inclined to relapse if well braced (Fig. 7).
Arthrogrypotic CVT are much less common (3% to 10%) compared with arthrogrypotic clubfeet (78% to 90%). CVTs are usually associated with the distal arthrogryposis, contractural syndromes, or the more severe syndromic or unclassified forms of arthrogryposis and rarely occur in amyoplasia. Treatment of CVT changed precipitously a decade ago when the Dobbs method was described.18 The feet undergo serial “reverse Ponseti” casting, stretching the foot into adductus, plantarflexion and supination, whereafter a limited talonavicular open reduction with pinning is performed. Even in cases of recurrence, correction can be reachieved in the same manner. Care should be taken to evaluate the calcaneal cuboid joint—if it too is initially dislocated, it should be percutaneously pinned at the time of surgical reduction.
Postoperatively the patient is casted for 6 weeks, then protected with an AFO molded to correct hindfoot valgus and forefoot abductus, transitioning to a University of California Biomechanics Laboratory (UCBL) when the patient demonstrates adequate ankle plantarflexion power for proper ambulation.
Treatment of lower limb deformities in patients with arthrogryposis can make meaningful and often life altering changes to their abilities, function, and independence. The constellation of deformities with which each patient presents can be overwhelming to the treating practitioner, unless they have knowledge of applicable procedures and an algorithm to follow. These children are usually of normal or above normal intelligence, and are motivated to achieve their potential, making them a very rewarding population with which to work.
The authors wish to thank Dr. Johannes Correll for his contributions to this article and sharing of clinical photographs.
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