Hip arthroscopy for trauma: Innovative techniques for a new frontier

When one thinks of hip arthroscopy, thoughts of labral tears or femoroacetabular impingement (FAI) may arise. But in the hip trauma setting, a recent review article by Foulk and Mullis on hip dislocations in the Journal of the American Academy of Orthopaedic Surgeons mentions hip arthroscopy as being useful for the minimally invasive management of loose bodies, labral tears and chondral defects.

Several authors have found intra-articular fracture fragments upon arthroscopic examination, even in the face of concentric reductions and the absence of visualized loose bodies on preoperative radiographs and thin-cut CT scans. Third-body wear may be a major factor in the development of the most common complication from hip dislocations, which is post-traumatic coxarthrosis, not femoral head osteonecrosis. Although controversial whether routine early surgical intervention is indicated after traumatic hip dislocations, few would argue against the osteosynthesis of displaced major weight-bearing fractures of the femoral head.

We recently published an article on the arthroscopic osteosynthesis of a displaced femoral head fracture and have since had other interesting trauma cases that we have managed with hip arthroscopy. The following is a review of four of them.

Dean K. Matsuda

Arthroscopic femoral head fracture osteosynthesis

An 18-year-old woman was ejected during a rollover motor vehicle accident and had surprisingly few injuries other than a rare isolated femoral head fracture without associated dislocation. She was referred to us for consideration of arthroscopic removal of her fracture fragment. She had a displaced large suprafoveal osteochondral fracture of the femoral head. Essential preoperative planning included a critical assessment of the fracture and an equally critical assessment of our arthroscopic hip experience.

Multiple images depicting a large displaced supra-foveal femoral head fracture.

Postoperative views after arthroscopic reduction and internal fixation using "chopstick" maneuver (shown intraoperatively in lower left inset) and Herbert screw fixation Images: Matsuda DK

We decided to attempt an arthroscopic reduction and internal fixation after full disclosure with the patient that this procedure had not yet been performed. Moreover, we committed to an open reduction and internal fixation surgery if an arthroscopic osteosynthesis failed rather than resort to arthroscopic removal of a major weight-bearing fragment.

We performed supine arthroscopic hip surgery under general anesthesia with intermittent hip distraction as an outpatient procedure, utilizing our two standard portals (anterolateral viewing portal and the modified mid-anterior working portal) plus an anterior portal.

Arthroscopic view of “clamshell” fracture being pried open with microfracture awl prior to arthroscopic osteosynthesis. The two cartilage surfaces of the folded-over fracture are represented by A and B.

Arthroscopic view of first headless screw being inserted after angle of approach has been improved with arthroscopic rim trimming. Note cannulated screw being inserted between trimmed acetabular rim and detached labrum.

Arthroscopic view of osteochondral fracture after fixation with two headless cannulated screws buried below femoral head chondral surface to level of subchondral bone (arrows).

Cross-over techniques and creativity

Crossover techniques gained from experience with arthroscopic FAI surgery, including comfort with 70° arthroscopic visualization and adequate capsulotomies permitting instrument navigation and fracture reduction, resulted in a successful surgery; anatomically based portal placement with attention to traction time and intra-articular fluid pressure led to a safe one.

Creative positioning of the operative extremity in atypical positions, even adduction, aided fracture reduction and fixation. The displaced osteochondral fragment was reduced using a “chopstick” maneuver described in the original article and then fixated with Herbert screws buried below the femoral head chondral surface while engaging subchondral bone.

Dynamic arthroscopic examination confirmed secure internal fixation permitting early hip motion with protected weight-bearing. We prefer radio-opaque metallic screws so that we may monitor possible early joint encroachment on intermittent standard postoperative imaging studies.

This patient healed uneventfully and at 2 years out, is asymptomatic and runs 3 miles daily.

Femoral head fracture with anterior dislocation

We have also managed a femoral head fracture associated with an anterior dislocation in a 22-year-old man sustained while snowboarding. A closed reduction had been performed within 4 hours of injury, and the patient was referred to us for evaluation 1 week later.

The patient underwent supine arthroscopic hip surgery 2 weeks postinjury and was found to have an unusual fracture configuration whereby the osteochondral fragment folded over on itself (presumably during the closed hip reduction) with articular cartilage circumferentially surrounding this “clamshell” fracture. We arthroscopically “pried open” the fracture with a microfracture awl prior to osteosynthesis with headless screws.

Arthroscopic rim reduction

It is important to note that this patient had pre-existing abnormal hip morphology consistent with cam-pincer FAI. As part of this outpatient procedure, an arthroscopic rim reduction was initially performed to permit an improved angle of attack for screw placement followed by labral re-fixation and femoral osteoplasty.

At 1-year postoperative, the patient is highly satisfied, plays tennis and snowboards.

Arthroscopic femoral head malunion

An 18-year-old man presented to our clinic with a malunion of a femoral head fracture sustained 9 months earlier from a gunshot injury. His initial open reduction and internal fixation appeared promising until his vertical fracture displaced with premature weight-bearing and resulted in a malunion with more than 1 cm of inferior displacement with secondary FAI of the intact lateral column of the femoral head against the lateral acetabulum.

Preoperative radiograph showing femoral head malunion with greater than 1 cm inferior translation of major head fragment (blue arrow) and secondary impingement of proximal extension of lateral femoral head column with lateral acetabulum (red arrow).	Arthroscopic view of femoral head reduction after malunion takedown with main femoral head segment (A) reduced into desired cephalad relationship to lateral column (B) and prior to arthroscopic bone grafting with demineralized bone matrix putty inserted via arthroscopic cannula and internal fixation.
Preoperative 3D CT scan of acetabulum with arrows noting the anterior acetabular fracture pattern.	Arthroscopic image showing the internal fixation of the anterior acetabular fracture with a second cannulated screw. Also note the rim-trimmed acetabulum with re-fixated labrum (left) and femoral osteoplasty (right).

Because the patient had painful restriction of hip motion and a noticeable leg length discrepancy, and because his young age dictated an aggressive approach to forestall eventual total hip arthroplasty, we opted for this arthroscopic approach. Moreover, we felt that by improving the femoral head reduction, a future surface replacement could become a viable option.

Arthroscopic takedown, bone grafting and internal fixation

We addressed this challenging situation in six separate steps. An arthroscopic takedown of the malunion was performed with small straight and angled osteotomes. Arthroscopic reduction was achieved using a combination of ipsilateral leg traction and mechanical translation with an osteotome applying a cephalad-directed force against the retained broken screw shaft, the latter permitting significant force to be distributed without iatrogenic damage to the mobilized segment.

Arthroscopic bone grafting was performed with insertion of demineralized bone matrix putty via an arthroscopic cannula. Percutaneous screw fixation was performed under arthroscopic and fluoroscopic guidance.

A residual proximal osteophyte of the lateral column was removed via arthroscopic burr resection. Finally, arthroscopic dynamic testing confirmed resolution of lateral impingement and a stable fracture construct permitting early motion.

Arthroscopic acetabular fracture osteosynthesis

Another recent case involved an 18-year-old man with a gunshot injury with resultant anterior column and wall fractures with intra-articular fracture fragments.

Preoperative imaging studies revealed FAI pathoanatomy.

Postoperative radiograph showing the reduced femoral head fracture with percutaneous screw fixation. Also note the absence of secondary lateral impingement.

Intraoperative fluoroscopic image under mild hip distraction showing the anterior acetabular fixation with two screws prior to removal of flexible guide pins.

We chose to stabilize his acetabular fracture as we did not want another malunion case from postoperative compliance issues. Arthroscopic placement of two cannulated screws was performed without incident. We also performed extraction of small fracture fragments and the bullet, plus rim trimming with labral re-fixation and femoral osteoplasty as part of this outpatient procedure.

Fluid extravasation into the intraperitoneal and retroperitoneal spaces with resultant abdominal compartment syndrome is rare but may occur, especially with acetabular fractures. Intermittent palpation of the draped abdomen and monitoring of core body temperature are prudent measures.

The last two cases were performed recently, therefore outcomes of substance are yet to be reported.

The preceding examples give an interesting and exciting glimpse into future possible applications of hip arthroscopy. An open procedure done well trumps a minimally invasive one done poorly; all of us recognize this. Anatomic reduction with secure internal fixation permitting early joint motion remains the goal.

However, if the arthroscopic equivalent can be performed in a safe manner, one can envision an expanding role of arthroscopy in select cases of hip trauma … well beyond that of loose body removal.

References:

• Foulk DM, Mullis. Hip dislocation: Evaluation and management. J Am Acad Orthop Surg. 2010:18(4):199-209.
• Matsuda DK. A rare fracture, an even rarer treatment: The arthroscopic reduction and internal fixation of an isolated femoral head fracture. Arthroscopy. 2009;25(4):408-412.

• Dean K. Matsuda, MD,can be reached at Kaiser West Los Angeles Medical Center, 6041 Cadillac Ave., Los Angeles, CA, 90034; 323-857-4477; e-mail: dean.k.matsuda@kp.org