Rectus Femoris Heterotopic Ossification: Combined Arthroscopic and Open Resection With Allograft Reconstruction and Concomitant Treatment of Femoroacetabular Impingement

Abstract

Background:

Heterotopic ossification (HO), or the abnormal formation of bone in extra-skeletal tissue, is a well-known complication of orthopedic trauma, tendon avulsions, chronic injuries, spinal cord injuries, and soft tissue damage from surgery. Heterotopic ossification commonly develops at the direct or indirect head of the rectus femoris. Athletes are especially susceptible to chronic microtearing and acute tendon avulsion, which may result in HO. When HO develops in the setting of concurrent intra-articular hip pathology, it may be amendable to arthroscopic excision, depending on its size and location.

Indications:

Heterotopic ossification that develops adjacent to the hip joint can affect range of motion of the joint and is often a source of pain. Arthroscopic excision is indicated when the HO that develops within or about the hip joint is symptomatic and is of a location and size that it can be reached and excised arthroscopically.

Technique Description:

In this technical note, we describe our method to excise HO using initial arthroscopic surgery to address femoroacetabular impingement syndrome (FAIS) and perform initial dissection of the HO fragment. Heterotopic ossification resection was then completed via an anterior open approach followed by reconstruction of the rectus femoris origin with Achilles allograft. This is followed by our HO prophylaxis protocol of indomethacin 75 mg daily for 4 days, followed by naproxen 500 mg 2 times daily through postoperative day 30, although many other regimens exist for HO prophylaxis.

Results:

Using arthroscopy for the removal of symptomatic HO at the time of surgery allows for the management of concomitant intra-articular pathology and efficient and precise dissection of the undersurface of the HO fragment.

Discussion/Conclusion:

Heterotopic ossification is a well-characterized complication of soft tissue damage, including tendon avulsion, trauma, previous surgery, and chronic microtear of the hip musculature. Oftentimes, HO develops in a location that can be reached arthroscopically. Surgeons should consider combining intra-articular arthroscopic surgery with arthroscopic excision of HO when appropriate, noting that there are many advantages to arthroscopic removal when compared with open procedures.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

We present a case of heterotopic ossification (HO) from the anterior inferior iliac spine with a combined arthroscopic and open approach.

In this video, we present a case in which a distant history of rectus femoris avulsion resulted in significant HO consistent with extreme subspine impingement. Our technique, as presented, uses a combined arthroscopic and open treatment of this large rectus femoris avulsion HO with Achilles allograft reconstruction of the proximal rectus femoris.

Heterotopic ossification of the anterior inferior iliac spine (AIIS) is typically the result of avulsion injury of the rectus femoris. In adolescents, injury occurs at the apophysis of the AIIS; whereas in adults, the injury is most often at the tendinous insertion, notably the myotendinous junction. In the acute setting, nonoperative management is typically successful. However, the development of HO can lead to decrease in hip range of motion and function, and as in this case, extra-articular subspine impingement. In treating this, both open and arthroscopic strategies have been described, with no consensus on the best approach.

In this case, we present an active 36-year-old man who works as a personal trainer with hobbies including martial arts. He had a remote history of 2 separate injuries at age 16 and 20 years that were described as “avulsion type” and located at the AIIS. He was treated nonoperatively and was able to function at a high level. However, he presented to clinic with a 5-year history of progressive right hip pain and restricted range of motion with a grinding sensation noted during deep squats.

Examination showed restricted hip flexion of 85° and limited internal rotation of 5°. The patient reported a grinding sensation was reproduced with internal and external rotation with the hip in a flexed position.

X-ray imaging, including standing AP pelvis, 45° Dunn lateral, and false profile demonstrated HO emanating from the AIIS, representing an extreme example of extra-articular subspine impingement.

Magnetic resonance imaging (MRI) further delineated the HO and the origin of the rectus femoris at the distal most aspect of the prominent HO. Magnetic resonance imaging also identified an anterosuperior labral tear as well as chondrolabral cartilage delamination, consistent with cam-type femoroacetabular impingement (FAI).

Low-dose hip preservation three-dimensional (3D) computed tomography was obtained to further assess bony morphology. This outlined the extent of the HO. From this, we also obtained measurements of the femoroacetabular joint showing combined impingement morphology with an elevated alpha angle of 73° and lateral center edge angle of 44°.

Based on his symptoms and radiographic parameters, the patient was indicated for hip arthroscopy to assess and treat intra-articular pathology in addition to arthroscopically assisted open resection of the HO.

For this procedure, patient is placed supine using a bed attachment designed to allow traction of the operative extremity during hip arthroscopy. Postless traction is the standard at our institution.

Diagnostic arthroscopy demonstrated anterosuperior tear of the labrum with delamination of the chondrolabral junction. Contrecoup wear pattern of the posterior acetabular articular surface was noted. This pattern of posterior chondrolabral wear can be seen in cam-predominant FAI, as the femoral head levers off the anterior edge of the acetabulum and is pushed posteriorly. In our patient, this was likely a result of significant extra-articular subspine impingement exacerbating the contrecoup phenomenon. Development of the synovial plane between the labrum and the overlying capsule allowed for visualization of the complete detachment of the labrum from approximately 12 o’clock to 2:30.

A DALA portal was then established to allow placement of suture anchors. Simple suture repair was performed using an antegrade passing device. Chondrolabral junction cartilage fraying, which was consistent with grade 2 chondromalaica, was gently debrided with a shaver. This wear pattern was quite consistent with cam-type impingement. However, given the significant limitation in the patient’s ability to flex his hip, it was surprising to see this degree of cartilage wear in this area of the hip. Traction was released and the hip reduced with visual confirmation of restoration of labral suction seal.

The pericapsular peripheral compartment was then entered and pericapsular fat debrided. Radiofrequency ablation was then used to clear soft tissue from the undersurface of the HO fragment and release any capsular adhesions to aid in capsular mobility. T capsulotomy was then created for visualization and osteoplasty of the cam deformity. Osteoplasty was performed and assessed with fluoroscopy, dynamic hip flexion, and internal rotation. The image on the left was taken prior to cam resection, and the image on the right shows restoration of femoral head/neck offset following resection of the cam deformity.

Arthroscopic dissection of the HO fragment was then continued. Fluoroscopic imaging confirmed that the distal extent was reached while undersurface attachments had been fully released. We kept the rectus tendon attached to the very distal end of the HO for ease of identification and later reconstruction during the open approach. Routine capsular closure was performed arthroscopically.

We then removed the arthroscope and proceeded to the open portion of the procedure. Maintaining the same positioning on the hip arthroscopy table, we created a bikini skin incision, distal to the anterior superior iliac spine (ASIS).

The interval between the sartorius and tensor fasciae latae (TFL) was identified. Care was taken to identify and protect the lateral femoral cutaneous nerve (LFCN) throughout the duration of the procedure.

A longitudinal incision was then made on the TFL side of the interval to avoid damage to LFCN. Alice clamps were placed on the fascia to allow for the underlying muscle to be swept and retracted laterally while the sartorius was retracted medially.

With deep retractors in place, the rectus femoris originating from the very distal aspect of HO fragment was visualized. The HO fragment was skeletonized with electrocautery to dissect remaining soft tissue off the fragment medially and laterally. Straight osteotome was then used to resect the fragment at its base.

Given the insertion of the rectus femoris to the distal aspect of the HO fragment measured 11 cm from the anatomic AIIS, an Achilles allograft used to reconstruction the insertion of the rectus femoris to its anatomic location with suture anchors.

Fluoroscopic images confirmed no remaining subspine impingement after HO resection.

After closure and dressing application with a cryotherapy device, the patient was discharged home the same day.

Postoperatively, we allowed 20% weight bearing on the affected leg with crutches for the first 6 weeks to protect the rectus femoris reconstruction. No hip brace was used. Beginning at 6 weeks, crutches were weaned once gait had normalized. We instructed the patient to avoid hip extension past neutral as well as hip abduction past 30° for the first 6 weeks to protect the rectus femoris graft and capsular closure. Running and impact activities were initiated around 3 months postoperatively with expected return to sport around 4 to 6 months postoperatively.

For HO prophylaxis, we gave the patient indomethacin 75 mg for 4 days, subsequently followed by 500 mg twice daily of naproxen for the first 30 days. Radiotherapy was not used as the evidence for its use in hip arthroscopy over chemoprophylaxis is limited. In addition, there were concerns regarding the effect of radiotherapy on the healing of the rectus femoris graft and capsular closure as well as potential long-term side effects of extra-radiation.

Here are comparison of preoperative and postoperative radiographs, demonstrating complete resection of the rectus femoris HO and resolution of both cam and subspine impingement with no evidence of HO formation.

As early as 4 months postoperatively, the patient demonstrated significant improvements in his range of motion in both hip flexion and internal rotation. He also demonstrated full strength in active hip flexion.

Specific to this unique procedure, we avoided inadequate resection of the HO fragment by demarcating and visualizing the edges of the fragment arthroscopically. The resection was performed with fluoroscopic guidance to assure appropriate resection. It is also important to prevent the HO from returning postoperatively. To minimize recurrence, we waited until the HO had matured before indicating the patient for excision. It is also important to assess for any barriers to adherence to prophylactic therapy. A common side effect of the non-steroidal anti-inflammatory drugs (NSAIDs) used for prophylaxis is gastrointestinal (GI) discomfort, which we alleviate with a proton pump inhibitor while on indomethacin, and longer if patient has a history of gastroesophogeal reflux disease. To avoid weakness that would occur if we completely detached the rectus femoris direct head, we elected to reconstruct this insertion with allograft and extend the postoperative restrictions beyond the typical 2 to 3 weeks of crutches we recommend for hip arthroscopy alone.

Regarding postoperative outcomes of HO-related impingement, previous case reports have shown improved range of motion and return to activities with open resection in addition to cam femoroplasty. While the role of concomitant hip arthroscopy has yet to be clearly defined, we found that the addition of arthroscopically assisted HO excision as well as simultaneous treatment of the intra-articular pathology allowed easier resection of the HO and treatment of all related hip pathologies.

Although rectus femoris reconstruction with Achilles allograft was not previously reported with resection of prominent AIIS HO, we found this to be a successful means of restoring the patient’s rectus femoris length and function postoperatively.

Thank you!