Pseudoparalysis in the Pavlik Harness: beware of septic arthritis

Abstract

Purpose

Pseudoparalysis of the leg occurring during use of the Pavlik Harness (PH) is a seldom-reported condition. Three cases of pseudoparalysis are reported here to illustrate the need for careful assessment of this condition.

Methods

A series of patients using the PH and presenting with pseudoparalysis was compiled following a retrospective review of case notes.

Results

In 3 cases, infants treated for developmental dysplasia of the hip using the PH were found to have developed a pseudoparalysis of the affected limb. All presented with similar signs, with the infant being systemically irritable and reluctant to move the limb. In 2 of the cases, this was related to the harness—its removal resulted in recovery of the affected limb. The third case was proven to be septic arthritis, unrelated to the harness, and treatment by means of arthrotomy, intravenous antibiotics and use of the PH for hip stabilisation was used successfully. In the first two cases, the pseudoparalysis was noticed at routine review clinic, and clinical assessment, ultrasound scan and blood tests were performed. The case of septic arthritis was similarly assessed, following referral by paediatric physicians.

Conclusion

Pseudoparalysis in the PH is a rare event and requires careful investigation.

Introduction

The Pavlik Harness (PH) is the most common device used in the initial treatment of developmental dysplasia of the hip (DDH) [1]. Several complications, such as inferior (obturator) dislocation [2, 3], deformity and lateral displacement of the femoral head [4], medial knee instability [5], brachial plexus palsy [6], femoral nerve palsy [7], iliotibial band contracture [8], and notably avascular necrosis (AVN) [4, 9–13], have been reported. Persistent subluxation, dislocation and failure to achieve reduction using the PH has also been well described [14–18].

We report three cases of infants treated for DDH using the PH who developed irritability and pseudoparalysis of the lower limb.

Methods

A total of 837 children have been treated using the PH, at Southampton General Hospital, since 1988 in a prospective study. After initial clinical assessment, patients treated in this way were reviewed weekly using a static ultrasound [16].

A retrospective review of infants treated for DDH at Southampton General Hospital was conducted, and 3 cases of pseudoparalysis were found.

Results

Case 1

Case 1 presented at 8 weeks, due to maternal history of DDH. Clinical exam was normal and ultrasound scan (USS) revealed a subluxed left femoral head (and no effusion). A PH was applied. A 1-week follow-up showed a persistently subluxed femoral head. Then, 5 days later, the patient presented to the paediatricians with a 2-day history of left groin swelling, anorexia and pyrexia. Lymphadenitis was diagnosed, and flucloxacillin treatment was started.

The child was reviewed 2 days later by the orthopaedic team and was found to be unwell, pyrexial, with an irritable hip and pseudoparalysis of the left leg. On examination, he had a temperature of 37.8°C, and an indurated, erythematous lump was present in the left groin. Blood tests revealed a white cell count (WCC) of 17.8 and C-reactive protein (CRP) of 56. USS showed a collection localised around the femoral head and soft tissue swelling. A diagnosis of septic arthritis was made, and arthrotomy revealed frank pus, from which gram-positive cocci were seen on microscopy. A PH was re-applied and intravenous (i.v.) antibiotics commenced.

Case 2

Case 2 presented at age 12 weeks, due to the risk factor of a calcaneo-valgus foot. On examination, the right leg was short, hip abduction reduced and Ortolani test positive. USS confirmed a reducible dislocation and a PH was applied. At 1 week, the mother reported that her baby had been unhappy all week and was not moving her right leg. On examination the baby was apyrexial and holding her right leg motionless. The hip was irritable on examination of range of movement, although full hip abduction was achievable. There was no evidence of femoral nerve palsy. X-ray showed no periosteal reaction and USS revealed a dislocated hip, although no joint effusion or collection was present. Bloods tests showed a WCC of 12.6, erythrocyte sedimentation rate (ESR) of 33 and a CRP level of less than 3.6. An infective cause was feared and i.v. cefuroxime was commenced. Clinical improvement was seen, antibiotics were converted to oral and the patient discharged after 1 week.

A further trial of the PH was attempted; however, irritability and pseudoparalysis recurred and the harness was discontinued. At 7 months, following appearance of the ossific nucleus (ON), the child was admitted and closed reduction performed. Good X-ray appearance and full function were found at the 6-year follow-up.

Case 3

Case 3 presented at 8 weeks, due to a clicky hip. Ortolani test was positive. USS showed complete left hip dislocation and a PH was applied. At the 1-week follow-up, the child was miserable and the left leg held motionless. There was irritability on passive motion. USS showed a dislocated hip and no effusion. Blood tests were normal. The PH was thus removed, and 1 week later, full active leg movement had returned.

The ON appeared at 4 months, following which a closed reduction was achieved. Subsequent reviews have shown marked acetabular dysplasia. At 6 years of age, the patient has normal function, equal leg length and satisfactory X-rays.

Discussion

Pavlik first reported the use of the harness, which bears his name, in 1957. It maintains flexion and allows gentle spontaneous reduction of the femoral head, while avoiding forced abduction; thus, it reduces the incidence of AVN [7]. The device design is simple, easy to use and apply, inexpensive, safe and effective on an outpatient basis [1]. All of these make it the most common device used for the initial treatment of DDH.

Important complications have been reported from its widespread use such as failure to obtain reduction [14–18], AVN [4, 9–13], inferior (obturator) dislocation [2, 3], femoral nerve palsy [7], brachial plexus palsy [6], deformity of the femoral head [4], medial knee instability [5] and iliotibial band contracture [8].

There are essentially three possible causes for reduced range of motion of the lower limb in the Pavlik harness:

• Nervepalsy: Femoral nerve and brachial plexus palsy have presented as true paralysis of a limb. Improper application, excessive flexion and inadequate size of harness have been quoted to be the causes [1, 6, 7, respectively]. An increased vigilance and regular adjustments of the harness under supervision have been emphasised to prevent such complications [16].

• Pseudoparalysis: Pseudoparalysis is sudden immobility, hypotonia and hyporeflexia and is usually a manifestation of a painful lesion in a limb. Conditions that have been associated with this presentation are pyogenic arthritis, soft tissue infection, osteomyelitis, fractures, traumatic periostitis, scurvy and congenital syphilis [19, 20].

• Decreased motion prior to reduction: It has been suggested by Suzuki that all babies are normally irritable in the harness for up to 1 week and may have some swelling around the hip [4]. He also suggests that the infant does not move its legs after application of the harness and remains in the frog leg position. Movement gradually improves, beginning with the ankles, followed by the knees and finally the hips. We, however, disagree with this view—although the movement of the leg is restricted initially, the child is seldom irritable and apparently systemically unwell.

“Irritability” in the harness is unusual. It was first noticed in Case 1, in which the child became pyrexial and irritable 5 days after subluxation was diagnosed. There was no effusion or systemic illness at the time of diagnosis. Septic arthritis in this child clearly represents a coincidental incident in the harness and the dislocation was not due to an effusion secondary to pyogenic arthritis. We were extra vigilant in the subsequent years and encountered two more children with systemic irritability and pseudoparalysis. These were all investigated to rule out the possibility of infection and were treated accordingly. Considering the serious nature of a delayed diagnosis of pyogenic arthritis, we recommend that irritability in the harness should be investigated before being considered to be due to intolerance of the harness or a “normal” phenomenon.