Successful Management of Stage I Congenital Knee Dislocation using a Pavlik Harness as a Novel Treatment Method: A Case Report

Introduction

Congenital Knee Dislocation (CKD) is a rare condition with an estimated incidence of approximately 1 in 100,000 live births. It is characterised by hyperextension deformity at the knee, often accompanied by anterior subluxation or dislocation of the tibia relative to the femur. CKD is considered as a part of ‘packaging disorders’, frequently associated with developmental dysplasia of the hip (50%), syndromic conditions such as arthrogryposis multiplex congenita and Larsen syndrome, although it may occur in isolation. [3] The classification system most used is that described by dividing CKD into three stages graded by passive range of flexion and radiologic appearance and can guide treatment (Table 1, Figure 1)

Figure 1: Tarek Classification of CKD [4].

Management depends on severity at presentation and timing of diagnosis. Early conservative treatment remains the cornerstone for Stage I deformities, with excellent reported outcomes. We present a case demonstrating successful correction using Pavlik harness as ana lternative to traditional serial casting.

Case Presentation

A full-term neonate was referred on first day of life with left knee hyperextension deformity noted at birth. This was the second child for the mother, with a previous healthy child and no knee deformity. The pregnancy had been uncomplicated, with no history of oligohydramnios or intrauterine constraint. There was no family history of musculoskeletal or syndromic conditions. On examination, left knee demonstrated marked hyperextension of approximate 20 degrees beyond neutral. Passive flexion was possible to 70 degrees without resistance. Hip examination was normal. Bilaterally, there was no thigh crease and no leg length discrepancy, with Ortolani and Barlow negative and full range of hip abduction. The feet were plantigrade, and there were no associated deformities, spinal or dysmorphic features (Figure 2).

Figure 2: Clinical appearance of left knee recurvatum 20 degrees achieving 70 degrees of flexion at birth presentation.

Ultrasound knee confirmed hyperextension at the knee joint without evidence of subluxation or dislocation, easily reducible into full flexion with a congruent knee joint. Radiologically there was no evidence of anterior tibial subluxation, and the joint remained congruent on gentle manipulation, consistent with Stage I congenital knee dislocation. Ultrasound of the hip showed left hip Graf type IIA immature hip with an alpha angle of 58 degrees, dynamically stable, and more than 2/3rds of the femoral head within the socket. The right hip was unremarkable with alpha angle >60degrees and Graf type I.

Results

A Pavlik harness was applied with the hips in approximately 90 degrees of flexion and the knees flexed to the maximum achievable angle without undue force (approximately 100 degrees initially) as shown in (Figure 3). The patient was reviewed at weekly intervals under careful clinical supervision. After a total of four weeks, the deformity had fully corrected, with the knee achieving full flexion and extension within normal physiological limits. The harness was discontinued, the knee was clinically stable, with no recurvatum noted on active or passive range of motion, indicating the knee was stable. There were no concerns regarding the hip. The patient was transitioned to physiotherapy focusing on gentle range-of-motion exercises.