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A 4-year-old boy with persistent L-hip pain, subluxation following closed reduction of hip dislocation
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A 4-year-old healthy boy sustained a traumatic dislocation of his left hip from falling off his bed the previous evening. He initially presented to an outside hospital with his left leg flexed and internally rotated. He had full motor and sensory functions and denied any numbness, but had pain overlying his left buttock. Soft compartments and intact pedal pulses were noted on presentation.
An unsuccessful attempt at closed reduction with conscious sedation was performed in the emergency department. The patient was then urgently taken to the OR for closed reduction of the left hip. Post-reduction radiographs demonstrated an incongruous reduction of his left hip joint (Figure 1), and CT and MRI scans were performed. Persistent lateral subluxation and concern for an incarcerated osteochondral or soft-tissue fragment was noted on post-reduction images (Figure 2 and Figure 3).
The patient was transferred to our institution for further evaluation and treatment by a pediatric orthopedic hip specialist. Prior to evaluation, the patient had an abduction pillow between his legs and was placed in a knee immobilizer. He was tender to palpation over the left lateral buttock and hip with soft compartments. He had intact and symmetric motor and sensory functions of the left lower limb and intact pulses with brisk capillary refill.
Image: Gourineni PV
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Persistent subluxation following closed reduction of a traumatic hip dislocation due to soft-tissue interposition
Pediatric hip dislocations are rare events that carry significant risks for long-term disability, if managed inappropriately. Posterior dislocations occur approximately 90% of the time, with low-energy mechanisms presenting in patients younger than 10 years old and high-energy mechanisms seen in adolescents due to the increased rigidity of their bony and soft-tissue structures.
Ideally, closed reduction with adequate sedation should take place within 6 hours to limit the risk of hip osteonecrosis (ON). Post-reduction radiographs also should be scrutinized carefully to evaluate for joint space asymmetry.
If any hip joint incongruity is suspected, additional higher level imaging studies are warranted to evaluate for labral, capsule or ligamentum teres interposition in addition to intra-articular osteochondral fragments.
Of all pediatric hip dislocations, 25% will have interposed soft-tissue or osteochondral fragments preventing a concentric reduction, thus requiring operative intervention.
Treatment with hip arthroscopy
After diagnosing the patient with persistent left hip subluxation due to soft tissue interposition following traumatic dislocation and a failed closed reduction, a left hip arthroscopy was performed to remove the interposed tissue and to provide concentric reduction.
The patient was placed supine on a fracture table, padding both feet well prior to placing feet into the foot holders. Traction was applied, and care was taken to avoid injury to all anatomic structures of the lower extremity and pelvis until adequate distraction of the left hip was noted under fluoroscopic guidance. An anterolateral portal was initially established under fluoroscopic guidance followed by a modified mid-anterior portal under direct visualization. A mass of soft tissue was noted lying between the femoral head and opposing joint surface (Figure 4 and Figure 5). The articular cartilage of the femoral head and acetabulum did not show any signs of chondral damage, and the labrum was slightly erythematous, but upon probing, it was found to be stable and firmly attached to the rim.
An arthroscopic shaver was used to debride the soft-tissue mass, which appeared to extend medially toward the ligamentum teres and pulvinar fat in the cotyloid fossa. Due to the posteromedial orientation of the soft-tissue mass, which was inaccessible with the anterior or modified mid-anterior portals, an additional posterolateral portal was made along with the use of a curved shaver to access and debride the remaining soft tissue.
Once most of the soft tissue had been resected, careful arthroscopic evaluation through all three portals demonstrated no evidence of soft-tissue interposition and traction was released. The medial joint space on fluoroscopy was noted to be symmetrical to that of the contralateral hip joint. Portal sites were then injected with local anesthetic and closed with 2-0 nylon sutures. The patient was placed in a fiberglass long-leg splint maintaining 20° of flexion and abduction. No neurological deficits were noted postoperatively, and no gross fluid extravasation was noted intra-abdominally or in the ipsilateral thigh compartments. The patient’s pain was well-controlled. He was cleared for discharge the following day and he was made non-weight-bearing for his lower left extremity and used a wheelchair, wagon or stroller for transportation.
Follow-up
At the patient’s 2-week follow-up, a concentric reduction was seen on radiographs (Figure 6). The patient reported minimal pain, had a discontinued splint and progressed to weight-bearing as tolerated.
At his 6-week follow-up, the patient maintained his concentric reduction and was running and jumping with full active and passive range of motion without restriction.
Discussion
Traditionally, in cases where a concentric closed reduction was not possible, open reduction with an arthrotomy and possible surgical dislocation was indicated to directly visualize the joint, remove incarcerated fragments and repair or debride soft tissue. However, the increased prevalence of adult hip arthroscopy with a focus on hip preservation has expanded the use of arthroscopy into the pediatric population. Challenges of hip arthroscopy in this population include smaller body habitus and the presence of tri-radiate, femoral and acetabular physeal cartilage. However, the advantages include a less invasive procedure with decreased morbidity, and excellent visualization of the joint surface and articular cartilage.
In 1977, Thomas P. Goss, MD, described a technique where he used an anterior and subadductor portal to treat developmental dysplasia of the hip (DDH), Legg Calve Perthes (LCP) and other disorders. Current indications include intra-articular evaluation of infantile DDH with arthroscopically assisted reduction, treatment of loose bodies, labral pathology and chondral tears associated with LCP, osteoplasty in femoral acetabular impingement and irrigation and debridement of a septic joint.
The use of hip arthroscopy as an alternative to open reduction and surgical dislocation is another emerging indication. In 1994, Graham S. Keene, FRCS, MBBS Orth, and Richard N. Villar, BSc (Hons), MA, MS, FRCS, presented one of the earliest cases using a supratrochanteric portal to remove multiple loose bodies in a 17-year old male after a hip dislocation. Naoya Kashiwagi, MD, and his colleagues successfully treated a 10-year old female with a ligamentum teres avulsion fracture with arthroscopy and removal of osteochondral fragments. In a cases series, Andrew C. Morris, MD, and his colleagues treated seven patients between ages of 8 years to 17 years old using anterior, anterolateral and posterolateral portals. The most common pathology seen in five cases of seven cases was an avulsion of a small bony fragment attached to the posterior capsular labral soft-tissue complex, which became enfolded and blocked the reduction; this was reduced without suture or bone repair. All osteochondral fragments were removed, and there were no cases of avascular necrosis or recurrent instability were reported at an average follow-up of 10 months.
Arthroscopy may also be used to treat patients with persistent symptoms following a closed- or open-hip reduction. Dennis R. Roy, MD, presented a case of a patient who underwent an open arthrotomy with a loose body removal and had persistent, postoperative pain. An arthroscopic procedure performed 6 months later revealed a torn and detached posterior labrum, which was debrided with resolution of symptoms.
Another case presented a patient with persistent hip pain 6 months after a concentric hip reduction. On subsequent arthroscopy, he was found to have a torn labrum, ligamentum teres and an impaction lesion on his femoral head, which were treated with debridement and microfracture.
Following reduction, most patients are managed with a period of protected weight-bearing before advancing activities. Close radiographic follow-up is necessary to monitor for ON.
Complications, benefits
Potential complications of hip arthroscopy include extravasation of fluid locally or intra-abdominally. Close monitoring of abdominal compartment pressures is required. Prolonged traction may result in lateral femoral cutaneous or pudendal nerve palsy, and inappropriate padding of traction boots may result in foot neurpraxias.
In addition, great care should be taken when positioning younger children on the traction tables given their smaller body habitus. Careful portal placement and insertion to avoid damaging the capsulolabral structures, physeal structures or articular surface are essential. Femoral head ON after hip arthroscopy has also been reported with injury to the medial and lateral femoral circumflex arteries due to traction placed during the procedure.
Hip arthroscopy offers significant clinical benefits compared to an open hip arthrotomy. Ahmed Mounir Moustafa El-Sayed, MD, compared open hip arthrotomy with arthroscopic drainage for treatment of the pediatric septic hip and found equal eradication rates of infection with no recurrence or development of complications in either group.
However, he discovered the arthroscopy group demonstrated significantly shorter hospital stays with equal recovery times and improved cosmetic outcomes due to use of smaller incisions. In addition, complications of open-surgical hip dislocation include the development of low-grade heterotopic ossification and trochanteric nonunion with a transtrochanteric approach.
While open reduction of the non-concentrically reduced hip has been the standard of treatment, hip arthroscopy is an emerging alternative that offers excellent joint space visualization and treatment of the underlying pathology, with decreased morbidity to the patient.
- References:
- Avascular necrosis of the femoral head after hip arthroscopy. Available at: http://www.hip-int.com/public/hip/Article/Attach.action?cmd=Download&uid=FA616FF4-0D13-40FF-ACCE-464E89F69C36\nhttp://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=reference&D=emed10&NEWS=N&AN=2011559465. Accessed: Oct. 12, 2016.
- Herrera-Soto JA, et al. J Am Acad Orthop Surg. 2009;17:15-21.
- Kashiwagi N, et al. Arthroscopy. 2001;doi:10.1053/jars.2001.8024.
- Keene GS, et al. Injury. 1994;doi:10.1016/0020-1383(94)90090-6.
- Morris AC, et al. J Pediatr Orthop. 2015;doi:10.1097/BPO.0000000000000670.
- Roy DR. J Child Orthop. 2009;doi:10.1007/s11832-008-0143-8.
- Roy DR. J Hip Preserv Surg. 2015;doi:10.1093/jhps/hnv070.
- Vialle R, et al. Pediatr Radiol. 2004;doi:10.1007/s00247-004-1299-0.
- Scher DL, et al. Clin Orthop Relat Res. 2010;468(11):3121-3125.
- El-Sayed AMM. J Child Orthop. 2008;doi:10.1007/s11832-008-0094-0.
- Ricciardi BF, et al. J Pediatr Orthop. 2014;doi:10.1097/BPO.0000000000000296.
- For more information:
- Walter Kim, MD, MPH, is a PGY-5 resident at the Department of Orthopaedic Surgery, University of Illinois and can be reached at email: walter.jw.kim@gmail.com.
- Matthew Craig, MD, is a PGY-3 resident at the Department of Orthopaedic Surgery, University of Illinois, and can be reached at email: MJC8719@gmail.com.
- Prasad V. Gourineni, MD, is an associate professor of pediatric orthopaedic surgery at the Department of Orthopaedic Surgery, University of Illinois, and can be reached at email: pgourineni@gmail.com.
Disclosures: Kim, Craig and Gourineni report no relevant financial disclosures.