Introduction

Central Core Disease (CCD) is a congenital myopathy first described by Shy and Magee in 1956, characterised histologically by well-demarcated central regions within skeletal muscle fibres lacking oxidative enzyme activity, termed “central cores”.¹ CCD is most commonly caused by mutations in the RYR1 gene, which encodes the skeletal muscle ryanodine receptor, a critical calcium release channel for excitation–contraction coupling.² Clinically, CCD presents with a spectrum of severity, from mild proximal muscle weakness to more pronounced neonatal hypotonia, delayed motor milestones, and persistent gait abnormalities.³

While muscle weakness in CCD is often static or only slowly progressive, orthopaedic manifestations — particularly scoliosis, developmental dysplasia of the hip (DDH), and generalised joint laxity — can significantly impact mobility, posture, and long-term independence.^4,5 These musculoskeletal complications frequently emerge or worsen during growth spurts, meaning early recognition and surveillance are vital to optimal outcomes. The orthopaedic challenges in CCD arise from the interplay between hypotonia, reduced muscle bulk, and ligamentous laxity, leading to abnormal mechanical forces across developing joints and the spine.⁶

Pathophysiology and Musculoskeletal Impact of CCD

Mutations in RYR1 disrupt calcium homeostasis in skeletal muscle, reducing contractile efficiency.^2,7 In CCD, type I muscle fibres are often hypotrophic, with reduced oxidative capacity in the central core regions.⁷ The resulting proximal muscle weakness is most pronounced in the hip and shoulder girdles, impairing dynamic joint stabilisation.

Ligamentous laxity, which may be intrinsic or secondary to reduced muscle tone, further destabilises joints.⁸ In weight-bearing joints, such as the hips, this combination increases the risk of subluxation and dysplasia during skeletal development. Similarly, reduced axial muscle tone impairs spinal stability, predisposing to scoliosis.⁹ The orthopaedic problems in CCD are therefore not purely secondary to weakness; they reflect an ongoing biomechanical imbalance between passive structures (ligaments, capsules) and active muscle control. Over time, static postural deviations become structural deformities, often requiring surgical intervention.

Scoliosis in CCD

Scoliosis, defined as a lateral curvature of the spine exceeding 10 degrees Cobb angle, is one of the most common orthopaedic complications in neuromuscular disorders, including CCD.¹⁰ Reported prevalence in CCD ranges from 15% to over 40%, with progression risk highest during rapid skeletal growth.^3,9 The pathogenesis involves asymmetric muscle weakness in the trunk and paraspinal muscles, leading to loss of spinal alignment control.

Clinically, scoliosis may present subtly in early childhood with asymmetrical shoulder height, waistline discrepancy, or pelvic tilt.¹¹ In CCD, curves may initially be flexible but can stiffen over time, particularly if accompanied by pelvic obliquity. Respiratory compromise is less common than in more severe neuromuscular conditions, but large thoracic curves can reduce lung volumes and impact endurance.⁴

Radiographic monitoring with standing posteroanterior and lateral views is essential for both diagnosis and surveillance.¹² During growth, curves of 20–40 degrees Cobb require follow-up every 6–12 months.¹³

Non-surgical management primarily involves physiotherapy to maintain spinal flexibility and core muscle strength, although its effect on curve progression is limited in neuromuscular scoliosis.¹⁴ Spinal bracing, such as thoracolumbosacral orthoses (TLSO), can provide temporary postural support but rarely halts progression entirely.¹⁵

Surgical intervention is indicated for curves exceeding 40–50 degrees, or for rapid progression, postural instability, or functional impairment. ¹⁵ Posterior spinal fusion with segmental instrumentation is the most common approach. Preoperative assessment must account for the malignant hyperthermia risk associated with RYR1 mutations.¹⁶ This involves avoiding triggering agents such as volatile anaesthetics and depolarising neuromuscular blockers, and ensuring dantrolene availability.¹⁶

Case series suggest that early surgical correction in CCD patients results in good postoperative alignment and improved sitting balance, although long-term mobility outcomes depend on preexisting muscle strength.^9,15 Postoperative rehabilitation should be cautious but progressive, emphasising respiratory physiotherapy and trunk reconditioning.

Hip Dysplasia in CCD

Developmental dysplasia of the hip is common in CCD, with presentations ranging from mild acetabular undercoverage to frank dislocation.^8,17 In CCD, hypotonia reduces the dynamic stability provided by periarticular muscles, while ligamentous laxity permits excessive joint translation.¹⁸ These factors disrupt the normal concentric reduction of the femoral head in the acetabulum during growth.

Early detection is critical. In newborns with CCD, clinical screening using Ortolani and Barlow manoeuvres should be performed at birth and during early check-ups.¹⁹ If instability is suspected, hip ultrasonography is recommended in the first six months, transitioning to plain radiographs thereafter.¹⁹

In infants, a Pavlik harness is the first-line treatment for reducible hips.²⁰ This device maintains the hip in flexion and abduction, promoting acetabular development. However, in CCD, prolonged harness use can exacerbate muscle weakness, so treatment duration must be carefully monitored.⁸ For older infants and children, surgical approaches such as open reduction, femoral varus derotation osteotomy, and pelvic osteotomy may be required to achieve stability.²¹ 

Decision-making in ambulatory patients must balance the need for stability against the potential for postoperative loss of walking ability due to muscle trauma.^8,21 In non-ambulatory patients, surgery is reserved for painful or unstable hips that interfere with sitting or hygiene.^17,22 Long-term hip surveillance is necessary, as secondary subluxations can develop during growth or after other orthopaedic interventions.²² Physical therapy focusing on strengthening hip abductors and extensors, alongside positioning strategies, can support joint integrity.

Joint Laxity in CCD

Generalised joint laxity is a recognised feature of CCD and may affect both small and large joints.^8,23 Laxity arises partly from hypotonia and muscle weakness, but there is also evidence of altered collagen cross-linking and connective tissue adaptation secondary to chronic underuse.⁸ Hyperextension of knees and elbows, excessive ankle dorsiflexion, and increased finger joint mobility are common findings.

While joint laxity itself is not always painful, it increases the risk of joint instability, recurrent sprains, and early degenerative changes.²³ In CCD, laxity contributes to orthopaedic complications by reducing the passive resistance that normally supports joint integrity. This is especially problematic in weight-bearing joints such as the hips, knees, and ankles, where instability can impair gait and increase fall risk. Assessment of joint laxity is commonly performed using the Beighton scoring system.²³ In CCD, this should be part of routine musculoskeletal surveillance, as progressive instability can undermine functional abilities over time.

Management is predominantly non-surgical. Physiotherapy focuses on strengthening periarticular muscles to improve dynamic stability, alongside proprioceptive training to enhance joint position awareness. Orthotic devices — such as ankle–foot orthoses or knee supports — may be indicated in cases of recurrent instability. Surgical stabilisation is rarely indicated for joint laxity alone in CCD, but may be considered if instability severely limits mobility or contributes to secondary joint degeneration.⁸ In such cases, careful anaesthetic planning is essential due to malignant hyperthermia susceptibility.¹⁶

Multidisciplinary Management Approach

Orthopaedic issues in CCD cannot be addressed in isolation. Optimal care requires a multidisciplinary approach involving orthopaedic surgeons, pediatric neurologists, physiotherapists, occupational therapists, respiratory physicians, and anaesthetists familiar with neuromuscular disorders.

Regular orthopaedic assessments — including spine and hip imaging — are recommended at least annually during growth, and more frequently if abnormalities are detected.^8,10 Physiotherapists play a crucial role in maintaining joint range of motion, preventing contractures, and optimising gait mechanics. In patients with scoliosis, targeted exercises to preserve trunk flexibility and strengthen paraspinal muscles can aid postural control, even if curve progression cannot be halted.¹⁴

Occupational therapists contribute by adapting seating systems, mobility devices, and environmental modifications to maximise independence in activities of daily living. For children with hip dysplasia or spinal deformities, appropriate wheelchair positioning and custom-moulded seating can prevent secondary complications such as pressure injuries and pelvic obliquity.¹⁵

Respiratory monitoring is important in CCD, particularly in cases with significant scoliosis. Pulmonary function testing should be performed regularly, and non-invasive ventilation considered if nocturnal hypoventilation develops.⁴ Speech and language therapists may be involved if bulbar weakness affects feeding or swallowing. Care coordination is especially important when surgery is indicated. Preoperative planning must include anaesthetic consultation to mitigate malignant hyperthermia risk, alongside respiratory optimisation to reduce postoperative complications.¹⁶ Postoperative rehabilitation must be individualised, balancing the need for mobilisation with the patient’s limited muscle endurance.

Prognosis and Long-Term Outcomes

While CCD is often considered non-progressive in terms of muscle strength, orthopaedic complications can significantly alter functional trajectories.^3,8 Unmanaged scoliosis can impair sitting balance, reduce pulmonary function, and limit mobility. Untreated hip dysplasia can cause pain, instability, and difficulty with transfers or walking. Joint laxity, if severe, may increase the risk of falls and joint degeneration.

The long-term outlook for patients with CCD has improved with earlier diagnosis, proactive orthopaedic surveillance, and advances in surgical techniques.^9,15 Many individuals remain ambulatory into adulthood, although some require mobility aids during later life. Importantly, appropriate orthopaedic management can preserve function and prevent secondary complications, even when underlying muscle weakness remains static.

Conclusion

Central Core Disease is a rare congenital myopathy in which orthopaedic complications — particularly scoliosis, hip dysplasia, and joint laxity — can substantially impact quality of life. The underlying mechanisms involve a combination of proximal muscle weakness, hypotonia, and ligamentous laxity, which disrupt normal joint and spinal biomechanics.

Scoliosis in CCD often emerges during growth and requires vigilant monitoring, with surgical correction indicated for severe or progressive curves. Hip dysplasia, common due to reduced muscular stability, necessitates early detection and timely intervention to preserve joint integrity and function. Joint laxity compounds these problems by reducing passive stability, increasing the likelihood of deformity progression and functional decline.

Management is inherently multidisciplinary, integrating orthopaedic surveillance, physiotherapy, assistive technology, respiratory care, and meticulous perioperative planning. While CCD’s muscle weakness is generally non-progressive, orthopaedic complications can evolve over time, underscoring the importance of early intervention and coordinated care. With proactive management, many individuals with CCD can maintain mobility, independence, and participation in daily activities well into adulthood.