Postless hip arthroscopy in the acute setting following open reduction internal fixation for comminuted posterior wall acetabular fracture dislocation

INTRODUCTION

The incidence of acetabular fractures is 3 out of 100,000 and is most commonly due to high-energy trauma.^[1] Posterior wall acetabular fractures are the most common acetabular fractures and are commonly complicated by hip dislocations.^[1] There is an increased risk of arthritis post-hip dislocation, potentially due to the presence of intraarticular loose bodies.^[2] The most common management for surgically indicated posterior wall fractures is open reduction internal fixation (ORIF); indications for ORIF include joint instability, fracture displacement, marginal impaction, and loose bodies.^[1] Complications include post-traumatic arthritis, avascular necrosis, infection, deep vein thrombosis, nerve injury, heterotopic ossification, and retained intraarticular loose bodies.^[1-3]

In certain cases of severe comminution, management is difficult as patients may present with tremendous injury to both the bone and the cartilage. Therefore, acute total hip arthroplasty is a consideration as well.^[1] In a study observing patients who had traumatic injury to their hip, intra-articular loose bodies were more accurately detected by arthroscopy than computed tomography (CT) and magnetic resonance imaging/Magnetic resonance angiography.^[4] Symptoms for these patients can include joint pain and sensations of catching, clicking, locking, and grinding.^[2] Intraoperative management of loose bodies during acetabular ORIF can be technically demanding as the orientation of the hip joint complicates the access to deep regions such as the cotyloid fossa, even with an open surgical approach.

Postless techniques are considered safe and effective means of gaining traction during hip arthroscopy.^[5,6] However, no data have been published on postless hip arthroscopy in the acute setting following acetabular ORIF. The following manuscript presents a case report of a patient undergoing hip arthroscopy following posterior wall ORIF for the removal of a retained intra-articular loose body. The patient provided consent that he was the subject of this case report.

CASE REPORT

A 39-year-old man presented as a polytrauma after a motorcycle accident (MCA) with right posterior wall acetabular fracture with hip dislocation [Figure 1]. Other injuries sustained included right patella fracture and left forearm open fracture. The fracture was classified as a highly comminuted posterior wall acetabular fracture with concern for loose osteochondral or chondral fragmentation intraarticularly. On the date of injury, the patient presented to the emergency department (ED) status post-MCA with a helmet and loss of consciousness. In the ED, the patient had his forearm splinted and knee immobilized. Closed reduction of the hip was performed, with the placement of a distal femoral traction pin for skeletal traction to maintain reduction.

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Figure 1:

Preoperative imaging of the pelvis demonstrating posterior wall acetabular fracture with hip dislocation and comminution: (a) axial CT image showing posterior wall fracture (red arrow), (b) axial CT image showing dislocation of femoral head (red arrow), (c) coronal CT image (red arrow), (d) 3D reconstruction (red arrow), and (e) AP pelvis radiograph after closed reduction (red arrow).

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On the following day, the patient had operative fixation of the right posterior wall acetabular fracture with internal fixation, with concomitant sciatic nerve neuroplasty at the hip. Many fragments of articular cartilage without bony support were identified inside the hip joint and were removed both manually and with flushing of the joint. No marginal impaction was noted. Initial reduction was held with k-wires and a ball spike pusher. Internal fixation consisted of an 8-hole plate for compression and buttress. A second supplemental 7-hole plate was utilized. Post-operative radiographs demonstrated excellent reduction and fixation [Figure 2].

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Figure 2:

Post-operative radiographs following open reduction internal fixation right acetabulum: (a) Anteroposterior pelvis (red arrow), (b) obturator oblique (red arrow), and (c) iliac oblique (red arrow).

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Subsequent post-operative CT scan demonstrated retained intra-articular loose bodies within the right hip at the cotyloid fossa, one of which measured 9 × 16 mm [Figure 3]. Revision open surgery for the removal of a loose body was felt to be a sub-optimal solution. A fellowship-trained hip arthroscopy specialist was consulted for consideration of hip arthroscopy surgery in the acute setting, given large intraarticular loose bodies.

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Figure 3:

Postoperative CT imaging following open reduction internal fixation (ORIF) right acetabulum showing retained intraarticular loose bodies: (a) coronal image (red arrow) and (b) axial image (red arrow).

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On post-operative day (POD) 4 after initial acetabular ORIF, the patient underwent the right hip arthroscopy with removal of loose bodies, debridement, and chondroplasty [Figure 4]. A Hana table (Mizuho Osi, Union City, CA) in a Trendelenburg position was used for positioning. A post-less technique for traction was utilized, with intraarticular needle placement for an air arthrogram performed before pulling for traction.^[5,6] Anterolateral and midanterior portals were utilized. He was noted to have a labral tear with absent segmental flap that was not visible posteriorly from 8:00 to 4:00, grade 4 changes to the acetabular cartilage at the superior weight-bearing surface with visible fissuring from fracture, but had a congruent articular surface without step off, and two large osseous/cartilaginous loose bodies in the cotyloid fossa. One loose body measured approximately 1 × 5 × 5 mm and was free-floating and excised. The second was 20 × 5 × 10 mm and was freed from the remaining chondral flap that was holding it to the central acetabular cartilage , and was removed piece by piece.

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Figure 4:

Intraoperative photos during hip arthroscopy following open reduction internal fixation (ORIF) right acetabulum: (a) intraarticular loose body (red arrow), (b) excellent articular surface reduction, (c) intraarticular loose body (red arrow).

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The patient also underwent ORIF of the forearm and patella fractures while admitted. The patient was discharged home on POD 9 with touch-down weight-bearing precautions for the operative extremity. His recovery was unremarkable, showing steady improvement. At follow-up with the orthopedic traumatologist at 6 and 10 weeks status post-ORIF, routine radiographs demonstrated implants in excellent positioning without evidence of loosening or failure, with concentric reduction and no signs of post-traumatic arthritis.

He was cleared for weight-bearing as tolerated at 3.5 months postoperative. At 11-month postoperative follow-up, the patient reported no pain, had regained a functional range of motion, was able to ambulate without an assistive device, and had returned to activity as tolerated.

DISCUSSION

Acetabular fractures remain a challenging clinical problem. Since most acetabular fractures are associated with high-impact injuries, the prognosis is poor.^[1] However, as techniques for ORIF have evolved, the prognosis has improved.^[1] Key factors influencing prognosis are the type of fracture and the condition of the hip at the time of injury; findings at one year post-injury are most indicative of prognosis post-treatment, as most hips show little improvement beyond this point.^[1]

The determination of optimal treatment depends on fracture severity and location, elapsed time since the injury, and displacement.^[1] Percutaneous fixation techniques are becoming more widely used, especially in patients who are polytraumatized or when an extensive procedure is not suitable.^[1] Total hip arthroplasty in the acute setting after acetabular fracture is indicated if patients present with pre-existing arthritis or if there is expected to be long-term complications after ORIF.^[7]

Acetabular fractures with associated hip dislocations are most often seen with a posterior wall fracture pattern. These fracture dislocations are inherently high risk for chondral damage and loose bodies. However, in pre-operative imaging, it is often observed that hip dislocations do not present with obvious intra-articular fragments.^[2] In a retrospective review analyzing patients who sustained traumatic hip injuries, 7 out of 9 patients were found to have loose bodies during arthroscopy despite negative pre-operative imaging (anteroposterior pelvis radiographs and CT scan).^[2] It is desirable to remove intra-articular loose bodies as these fragments are associated with acetabular dislocation and fracture and are linked to degenerative changes.^[2]

Hip arthroscopy for traumatic hip injuries is becoming increasingly common due to its minimally invasive nature. Niroopan et al. found that in post-hip trauma, arthroscopy had a success rate of 96%.^[8] Indications for hip arthroscopy included acetabular fracture fixation with osteochondral injury, loose body removal, labral injury, debridement of ligamentum teres avulsion, bullet extraction, femoral head fixation, and stable acetabulum with no indication for open reduction.^[3,8] Risks of hip arthroscopy in the traumatic setting can include retained loose bodies, avascular necrosis, thromboembolic event, abdominal compartment syndrome, and transient lateral femoral cutaneous nerve palsy.^[8] Arthroscopy for high-impact trauma should be carefully monitored to avoid compartment syndrome or hemodynamic compromise as a consequence of arthroscopic fluid extravasation.^[8]

A case series involving 17 patients with posterior hip dislocation resulting from high-energy trauma underwent closed reduction, followed by arthroscopy, an average of 3 months later.^[9] 14 of the 17 patients had intra-articular loose bodies, which were successfully removed via arthroscopy.^[9] Fourteen patients were followed for 3 years or more and showed a statistically significant improvement in Preoperative Western Ontario and McMaster Universities Osteoarthritis Index scores, from 46 pre-operatively to 87 at the 3-year follow-up appointment.^[9] The success of arthroscopy depended on multiple factors: injury sustained, duration between dislocation and reduction, risk factors, and associated injuries.^[9]

Hip arthroscopy following ORIF of the acetabulum offers a minimally invasive method to address persistent intra-articular issues such as loose bodies. Most published studies looking at this clinical scenario describe the secondary procedure taking place weeks to months after the index procedure. Several downsides exist in waiting to proceed with arthroscopy, including technical difficulty, prolonged patient rehabilitation/recovery, and early post-traumatic chondral damage. One concern for early hip arthroscopy after acetabular ORIF is the need for hip joint distraction. Postless techniques for hip arthroscopy, including the use of intra-articular needle placement for an air arthrogram before pulling for traction, provide a means of decreasing axial load while gaining the necessary traction. This is an ideal option after acetabular ORIF to minimize the risk of disturbing the fracture fixation. This case report describes hip arthroscopy with postless technique being performed safely in the acute setting following ORIF, where the secondary surgery was performed 3 days after the initial ORIF. Future studies should examine expanded indications for hip arthroscopy early after acetabular ORIF.

CONCLUSION

This case highlights the successful use of postless hip arthroscopy following comminuted right posterior wall acetabular fracture with hip dislocation from high-energy trauma. Early intervention of ORIF and arthroscopy with the removal of loose bodies, debridement, and chondroplasty showed promising results–decreased morbidity, better prognosis, and fewer long-term complications. This case shows that postless hip arthroscopy techniques warrant further investigation for acute traumatic fractures and dislocations.