A review of the orthopedic interventions and functional outcomes among a cohort of 114 children with arthrogryposis multiplex congenita

Table 2 lists the number of lower extremity surgical procedures per child across AMC category and Table 3 depicts the various surgical procedures recorded in the medical records according to joint. There were 496 surgical procedures among the 114 cases, consisting of bony surgeries, soft tissue releases, internal or external fixator and serial casting, resulting in an average of 4.35 operative procedures per participant (range: 0 to 14). The median number of surgical procedures among the participants was 4 (lower quartile = 2, upper quartile = 6). Seventeen children (14.9%) did not undergo any surgery. The most frequent site for surgical intervention was the foot and ankle with 255 procedures within this cohort, followed by the hip with 116 procedures. Fourteen children (12.3%) underwent a surgical procedure for deformity of the upper extremity. The most common procedures performed for the UE included first web-space and thumb-in-palm releases. Ninety-two children (80.7%) had a surgical procedure to the lower limb, with the most common being foot or ankle soft tissue releases and Achilles tendon lengthening. The highest number of lower extremity surgical procedures in all AMC categories (Amyoplasia, Distal and Other) was 7. The median number of lower extremity surgical procedures was 2 in the cohort (median of 1 in the Amyoplasia group, 2 in the distal group and 2 in the Other group). Eleven participants (9.6%) had surgeries in both the LEs and UEs.

The functional status of participants is described in Table 4. Among the participants for whom the goal of walking was age appropriate ( n = 44), those with distal arthrogryposis were all community ambulators ( n = 43) except for one participant for whom ambulation status was unspecified. Ambulation level was more varied in the Amyoplasia and Other groups with only 59.0% and 52.9% respectively able to ambulate, with or without a device. Among the children with Amyoplasia, 12 of the 23 participants (52.1%) able to ambulate required a device when walking and in the Other group, 3 of the 9 ambulatory patients (33.3%) required a device when walking. In addition, 42 participants of the whole cohort reported wearing orthoses at some point during their rehabilitation process, either knee-ankle-foot (KAFOs, n = 11) or ankle-foot orthoses (AFOs, n = 31).

Similarly, 97.2% of the distal arthrogryposis group were able to transfer to various surfaces in the home independently while 42.3% and 71.4% of the Amyoplasia and Other groups respectively were autonomous during these activities. In terms of self-care, 75.0% of the group with distal arthrogryposis were independent compared to those with Amyoplasia or those in the Other category with rates of 28.0% and 64.3% respectively. Details on functional abilities in self-care and transfers were not specified or the subject was too young to assess these skills in about half of individuals in the Amyoplasia group.

4. Discussion

The aim of this retrospective chart review was to describe the functional status, clinical presentation, and orthopedic interventions of children with AMC who were followed in a pediatric orthopedic setting. As previously described in literature [1, 5], our data confirmed that AMC affects girls and boys roughly equally (52.6% vs. 47.3%). Classifying the category of AMC was done in the context of an orthopedic visit, so the use of known classification systems, such as the ones by Bamshad et al. [13] and Hall [14] was not systematic. The literature reports that over 50% of individuals with AMC are diagnosed with either Amyoplasia or distal arthrogryposis [11]. Amyoplasia is the most common form of AMC and distal arthrogryposis the second most common [15]. Our findings show a higher proportion of children with Amyoplasia and distal arthrogryposis at our Hospital than those with CNS involvement. As we are a pediatric hospital providing elective orthopedic surgery, it seems likely that children with multiple co-morbidities, particularly CNS involvement are not referred to our Hospital to the same extent as children with Amyoplasia and distal arthrogryposis.

Although several studies have identified genetic etiologies related to AMC [2, 11, 16, 17, 18], there is a need for identifying the genetic pathways associated with the different forms of AMC. Genetic testing is not typically offered to patients and families in community health care settings. Thus, a genetic workup should be made available to families of children with AMC to gain a better understanding of the underlying mechanisms associated with AMC, to inform them about the long-term trajectories of specific diagnoses, and for genetic counselling. Genetic testing would also help rule out other possible syndromes in the differential diagnosis that would require different management. Genetic counselling should be repositioned at the beginning of the diagnostic and therapeutic endeavor within a multidisciplinary clinical context to reach the best functional outcome possible through early, tailored therapy [19].

The majority of children with Amyoplasia (55.5%) had involvement of all three joints of the UEs, which might explain the finding that only 28.0% were independent walkers, and that 32.0% required technical or human aid to achieve independence in self-care activities. In the distal group, joint involvement is much less predominant at the levels of the shoulder and elbow and not surprisingly, rates of autonomy in self-care are much higher (e.g., 75.0% versus 28.0%). This finding suggests that proximal upper extremity involvement is a critical factor in reaching independence in self-care. Nevertheless, only a small percentage of the children with Amyoplasia had UE surgery to address these contractures. The paucity of scientific literature on the effectiveness of interventions in the UE in AMC highlights the need for research on operative and non-operative outcomes in this area. It has been suggested in the literature that coordination of upper and lower limb surgical procedures can be a good strategy to limit anesthetic exposure and maximize rehabilitation early in life [20]. The annotated definition of AMC proposed by Dahan-Oliel and colleagues in 2019 states that spinal deformities may be present at birth or may develop during childhood and adolescence [15]. Although we did not report on spinal involvement for the 114 children in this retrospective chart review, three children or 2.6% of the cohort had spinal fusion. Given the broad age range of our sample, it is possible that other participants eventually required surgical treatment of their spinal deformities at a later date, which was not captured by our review. As our Hospital provides elective orthopedic care, some spinal surgeries for children with intubation difficulties are performed at an affiliated children’s hospital that has an intensive care unit. Therefore, some of the cases reviewed may have had spine surgeries that were not reported at our Hospital.

Children in all three classification groups had joint involvement of all three levels of the lower extremity. Not surprisingly, those with distal AMC were found to have the least hip involvement, 52.1%. The Amyoplasia group were most affected at the foot and ankle, with 91.5% of the participants being recorded with unilateral or bilateral contractures at that level. Relatively less involvement of the hip and knee appears to be associated with independence in ambulation and transfers as noted by the high rates of community ambulation without devices in those with distal arthrogryposis. In contrast to the UE, interventions addressing the LE issues were frequent. This finding correlates with the incidence of 5 subjects (4.4%) in our review with only UE involvement. Children with joint contractures of only the UE or LE may not be readily detected with AMC, as contractures of several different body parts may be associated with a more characteristic AMC phenotype.

Studies have also shown that even with severe initial presentation, children with AMC can achieve functional outcomes through early treatment interventions and individualized and aggressive management [21, 22, 23, 24]. Documentation regarding rehabilitation as well as the use of standardized functional measures was lacking in the charts reviewed, leading us to infer that referral to rehabilitation, particularly in the early years of this review was inconsistent. Functional outcome measures inform evidence-based practice and are essential for the evaluation of treatment effectiveness. In lieu of the use of outcome measures, a classification system to describe ambulation was used which was based on previous work of Dr. van Bosse (personal communication). This classification system was then extrapolated for describing self-care and transfers. This simple classification system enabled accurate description in a large sample of patients in AMC despite the retrospective nature of this study.

Our findings of multiple joint involvement, the extensive orthopedic management as well as the need for aids in daily activities are in line with the current literature [25, 26, 27] and emphasize the importance of early referral to rehabilitation and orthopedics. Therefore, it is suggested that the management of children with AMC should be within a multidisciplinary context, and should encompass genetics, orthopaedics, nursing, rehabilitation, social services, orthotics, and other professions to meet the spectrum of needs children with AMC may experience. This is in line with previous studies that demonstrate the importance of integrating the care of children with AMC with a multidisciplinary team approach [19, 28]. Indeed, a multidisciplinary approach could potentially diminish waiting times for families, provide specialty coordinated care across several health care disciplines in one setting, ensure early genetic evaluation, and improve the quality of care provided as has been demonstrated in the care of children with chronic musculoskeletal conditions [29, 30]. For these reasons, we established a monthly multidisciplinary clinic for children with AMC in 2016, which provides coordinated care from the following disciplines: orthopedic subspecialties in upper extremities, lower extremities and spine, rehabilitation, social work, radiology, dietetics, orthotics, and metabolic investigation [31].

As our Hospital provides care to children with musculoskeletal conditions across the geographic landscape, our team piloted the remote delivery of a home exercise program for youth with AMC living across Canada [32]. The pre-established clinic model and prior use of telemedicine in AMC greatly facilitated the provision of continued care to our patients when the COVID-19 pandemic manifested in March 2020. Our experience pre-COVID-19 helped us immensely in facing the realities of a pandemic while providing care, and demonstrated that our clinic model could also be delivered utilizing a remote approach. Indeed, telemedicine plays a key role in prioritizing the treatment of common orthopaedic conditions and is a safe modality to deliver care when physical distancing measures must be implemented [33]. In fact, in July 2020 with traveling restrictions still in place, the multidisciplinary AMC clinic was delivered via telemedicine. The use of telemedicine to deliver multidisciplinary care has also been implemented for other populations with rare musculoskeletal conditions, including osteogenesis imperfecta, and could be applied to other pediatric populations at our center, such as skeletal dysplasias and neuromuscular conditions.

Limitations of this retrospective review include the lack of routine genetic testing which precluded the provision of a specific AMC diagnosis. Due to the lack of information on the underlying genetic diagnosis, categories of AMC may have been misclassified. Furthermore, the inconsistent referral of patients to rehabilitation services resulted in limited information of functional status. In cases when patients were referred to rehabilitation, a standardized evaluation protocol was missing. Therefore, the evaluation of the effectiveness of specific interventions was not possible. This highlights the need for the development of guidelines for early diagnosis and management of arthrogryposis as well as long-term follow-up using standardized functional outcomes. As children with arthrogryposis have a heterogenous presentation, the development of clinical tools specific to their wide range of physical presentations should be a research priority.

As AMC is rare, the relatively large sample size of this chart review allowed better insight and understanding into the challenges associated with multiple congenital contractures. Severe upper limb involvement is clearly associated with more challenges to reaching autonomy in self-care. Lower limb involvement at the proximal level is often associated with a poorer prognosis in terms of mobility outcome. However, this also highlights that children with distal arthrogryposis can usually be independent in self-care, transfers and mobility and should be treated with those objectives in mind.

Moving forward, multi-site prospective studies are required in the fields of genetics, treatment effectiveness and adult outcomes [34]. The findings of this study demonstrate the importance of genetic testing to provide accurate diagnosis and classification, researching and promoting the use of standardized functional measures in AMC, and the provision of care within a multidisciplinary context.