Endoscopic Approach to Proximal Hamstring Avulsion Repair

Abstract

Background:

Endoscopic repair of a proximal hamstring avulsion promotes precise anatomical repair and lowers the risk of neurovascular injury.

Description:

Indications for proximal endoscopic repair of the proximal part of the hamstrings include acute tears of 2 tendons with >2 cm of retraction in young active patients, acute complete tears of 3 tendons with >2 cm of retraction, or failed conservative treatment of tears of ≥2 tendons with ≤2 cm of retraction. Repair of a proximal hamstring avulsion is performed using 2 portals. The medial portal is developed percutaneously under fluoroscopic guidance. The lateral portal is developed under direct visualization. The footprint of the hamstrings is identified from medial to lateral. The sciatic and posterior femoral cutaneous nerves must be carefully identified and protected. The avulsed tendons are fixed with suture anchors with the knee in flexion.

Alternatives:

Conservative treatment is commonly used to treat injuries of the musculotendinous junction (type 2), incomplete or complete avulsion with minimal retraction (≤2 cm) (type 3 or 4, respectively), and patients with limited mobility or severe comorbidities¹. The initial treatments consist of RICE (rest, ice, compression, and elevation), protective ambulation, and then physical therapy. Open repair is used for incomplete or complete avulsion with >2 cm of retraction, or when conservative treatments have failed^1-3. Open reconstruction is used for chronic avulsion with tendon retraction of >5 cm^4-6.

Rationale:

Endoscopic surgery is a minimally invasive procedure that offers excellent visualization of the subgluteal space without gluteus maximus muscle retraction. In open repair, the inferior border of the gluteus maximus muscle is mobilized to access the ischial tuberosity. The mean distance (and standard deviation) from the inferior border of the gluteus maximus muscle to the hamstring origin has been reported to be 6.3 ± 1.3 cm, which is close to the mean distance from the inferior border of the gluteus maximus to the inferior gluteal nerve and artery, which has been reported to be 5.0 ± 0.8 cm⁷. Open repair, which requires gluteus maximus retraction, poses an injury risk to the inferior gluteal nerve and artery. Open repair increases the risk of wound infection because the incision involves the perineum⁸. The feasibility of the endoscopic repair depends on the chronicity and amount of tendon retraction. It is feasible for a symptomatic tear of ≥2 tendons with a retraction of ≤2 cm. Mobilization of the retracted tendon is challenging in endoscopic repair. In acute injuries, the degree of retraction is not critical because the tendon is easily mobilized. Chronic injuries (>2 months) and those with far tendon retraction (>5 cm) are not suitable for endoscopy⁹. In chronic injuries with incomplete or complete avulsion with minimal retraction (≤2 cm) (types 3 and 4) that have failed conservative treatment, endoscopy is suitable since the tendon is not retracted¹. Endoscopic repair can be converted to an open procedure in difficult endoscopic conditions.

Introductory Statement

Endoscopic proximal hamstring repair promotes a minimally invasive, precise anatomical repair that may result in superior outcomes and reduced complications compared with those associated with an open approach, as observed in studies comparing endoscopic procedures and their open surgery counterpart^10-14.

Indications & Contraindications

Indications

• Proximal hamstring avulsions with ≤5 cm of retraction.

Contraindications

• Contraindications for operative proximal hamstring repair^1,15:

  • Severe comorbidities.

  • Single tendon injury without a previous trial of nonoperative treatment.

  • An elderly and low-demand patient.

  • Chronic injuries with no functional deficits.

  • Intramuscular injuries and musculotendinous junction injuries.

• Contraindication for endoscopic repair⁹:

  • Chronic tears of ≥2 tendons with >5 cm of retraction.

Step 1: Preoperative Preparation (Video 1)

Video 1.

Download video file ^{(46MB, mp4)}

DOI: 10.2106/JBJS.ST.19.00037.vid1

Introduction.

Evaluate the neurological status, inspect the pelvic radiograph, and confirm the injury type, extent of retraction, and concomitant soft-tissue injury on the magnetic resonance imaging (MRI) scan.

• Evaluate the neurological status, particularly of the sciatic nerve. If sciatica is present, the avulsed tendon may be adhered to the sciatic nerve.

• Inspect the pelvic radiograph to exclude osseous avulsion injury (type-1 injury)¹.

• Confirm the injury type, extent of retraction, and concomitant soft-tissue injury on the MRI.

Step 2: Anesthesia and Positioning (Video 2)

Video 2.

Download video file ^{(7MB, mp4)}

DOI: 10.2106/JBJS.ST.19.00037.vid2

Setup and portals.

Use general anesthesia, place the patient in the prone position, ensure that all osseous prominences are padded, and drape the affected side with sterile technique, allowing free mobilization of the limb.

• Use general anesthesia with complete muscle relaxation.

• Use hypotensive anesthesia to avoid using high irrigation pressure.

• Place the patient in the prone position with slight hip flexion, hip abduction, and knee flexion on the radiolucent operating table.

• Pad all osseous prominence areas.

• Drape the affected side with sterile technique, which allows free mobilization of the limb (Fig. 1).

Fig. 1.

Figs. 1-A, 1-B, and 1-C Patient positioning. Fig. 1-A Careful padding of all osseous prominence areas is needed to prevent pressure sores during surgery. Fig. 1-B The patient is placed in the prone position with slight hip flexion, hip abduction, and knee flexion on the radiolucent operating table to relax the gluteus maximus and sciatic nerve. Fig. 1-C Sterile draping on the right hip and thigh allows free mobilization of the limb.

Step 3: Surface Landmark Outline and Portal Placement (Videos 3 and 4)

Video 3.

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DOI: 10.2106/JBJS.ST.19.00037.vid3

Portal landmark.

Video 4.

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DOI: 10.2106/JBJS.ST.19.00037.vid4

Exposure of subgluteal space.

After identifying the ischial tuberosity and gluteal fold, mark the medial and lateral portals, establish the medial portal first and insert a 70° arthroscope, and then create the lateral portal and insert a shaver.

• Identify the ischial tuberosity and gluteal fold.

• Mark the medial portal in the gluteal fold at approximately 2 cm medial to the lateral border of the ischial tuberosity.

• Mark the lateral portal in the gluteal fold at approximately 4 cm lateral to the lateral border of ischial tuberosity (Fig. 2).

• Establish the medial portal first.

• Directly insert a needle percutaneously to the medial aspect of the ischial tuberosity, using tactile sensation and fluoroscopic guidance. Then insert the nitinol wire and trocar sheath.

• Insert a 70° arthroscope in the medial portal (Fig. 3).

• Create the lateral portal under direct visualization.

• Insert a shaver in the lateral portal.

• Create a space under the gluteus maximus muscle (subgluteal space) by shaving the remaining fibrous tissue between the ischium and the gluteus maximus muscle from medial to lateral.

Fig. 2.

An outline of the skin incisions for portal placement on the posterior aspect of the right hip. The medial portal (MP) is located in the gluteal fold (green dashed line) and just medial to the lateral border of the ischial tuberosity (yellow dashed line). The lateral portal (LP) is located in the gluteal fold and approximately 4 cm lateral to the lateral border of the ischial tuberosity.

Fig. 3.

A 70° arthroscope is placed in the medial portal (MP) of the posterior part of the right hip. The medial portal is created first under fluoroscopic guidance. Then the lateral portal (LP) is created under direct visualization.

Step 4: Identification of Ischial Tuberosity, Hamstring Tendon, and Sciatic Nerve (Video 4, 5, and 6)

Video 5.

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DOI: 10.2106/JBJS.ST.19.00037.vid5

Identification of tear.

Video 6.

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DOI: 10.2106/JBJS.ST.19.00037.vid6

Identification of nerve.

After obtaining a clear space under the gluteus maximus muscle, identify the caudal tip of the ischial tuberosity and the hamstring tendon, and then dissect anteriorly and laterally to identify the sciatic nerve and the posterior femoral cutaneous nerve, which must be protected before and during mobilization and fixation of the tendons.

• After obtaining a clear space under the gluteus maximus muscle, identify the caudal tip of the ischial tuberosity, as well as the location of its medial and lateral borders.

• Identify the hamstring tendon.

• Using a combination of a switching stick and electrocautery, dissect anteriorly and laterally to identify the sciatic nerve, which is located a mean (and standard deviation) of approximately 1.2 ± 0.2 cm lateral to the most lateral part of the ischial tuberosity⁷ (Fig. 4).

• Using a switching stick as a tactile aid, visualize the posterior femoral cutaneous nerve, which is often the first nerve identified during dissection and serves as a signal of the main sciatic nerve³ (Fig. 5).

• Carefully release any fibrous tissue from the proximal to distal direction along the nerves.

• Ensure that the nerves are identified and protected prior to and during mobilization and fixation of the tendons.

• Identify the hamstring footprint for any obvious tear.

  • In acute tears, the tear is easily recognized, and the tendon is often retracted distally with occasional hematoma⁹.

  • In chronic partial tears, the tear can be identified by tissue ballottement with palpation⁹.

Fig. 4.

The drawing shows the sciatic nerve, which is located a mean of approximately 1.2 ± 0.2 cm lateral to the most lateral part of the ischial tuberosity. SmM = semimembranosus muscle, SmT = semitendinosus muscle, and LHBF = long head of the biceps femoris muscle.

Fig. 5.

The drawings and intraoperative image show the location of the sciatic nerve and posterior femoral cutaneous nerve. The posterior femoral cutaneous nerve is often the first nerve identified during dissection before the sciatic nerve.

Step 5: Preparation for Repair (Video 7)

Video 7.

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DOI: 10.2106/JBJS.ST.19.00037.vid7

Anchor placement.

Clean the remaining hamstring tissue on the lateral aspect of the ischial tuberosity, freshen the devitalized tissue at the tendon edge, and use a burr to form a bleeding cancellous surface on the ischial tuberosity.

• Clean the remaining hamstring tissue on the lateral aspect of the ischial tuberosity with an oscillating shaver to establish an osseous contact surface.

• Freshen the devitalized tissue at the tendon edge.

• Use a 5.5-mm burr to perform ischial tuberosity decortication to form a bleeding cancellous surface.

Step 6: Anchor Placement and Suture Management (Video 8 and 9)

Video 8.

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DOI: 10.2106/JBJS.ST.19.00037.vid8

Placement of stitches.

Video 9.

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DOI: 10.2106/JBJS.ST.19.00037.vid9

Final repair.

Place the suture anchors at the footprint through the lateral portal under fluoroscopic guidance, protect the sciatic nerve and pass stitches through the torn tendon using the lateral portal, tie the stitches, place the knee in flexion throughout closure, check for hemostasis, close the skin, and apply a hinged knee brace.

• Place the suture anchors at the footprint through the lateral portal under fluoroscopic guidance (Fig. 6).

• With sciatic nerve protection, pass the stitches using a suture-penetrating device through the torn tendon using the lateral portal with a horizontal mattress configuration (Fig. 7).

• Tie the stitches, with the knee in 40° to 60° of flexion (Fig. 8).

• Place the knee in a flexion position throughout the closure.

• Meticulously check for hemostasis to prevent postoperative hematoma formation and sciatic nerve compression.

• Ensure that the sciatic nerve is tension-free after fixation of the torn tendon.

• Close the skin.

• Place the knee in a hinged knee brace fixed in 50° of flexion.

Fig. 6.

The drawing and intraoperative images show suture anchor placement at the footprint through the lateral portal under fluoroscopic guidance.

Fig. 7.

The drawings and intraoperative image show suture passing through the hamstring tendon in the horizontal mattress configuration.

Fig. 8.

The drawing shows the final construct of the proximal hamstring repair.

Step 7: Postoperative Rehabilitation

Manage the patient with the hinged brace and toe-touch weight-bearing on crutches for the first 6 weeks postoperatively, allow increased weight-bearing as tolerated at 6 weeks, permit concentric strengthening after 8 weeks, and allow eccentric strengthening and light jogging, short sprints, and closed-chain plyometrics at 3 months.

• Manage the patient with the hinged brace for the first 6 weeks after surgery; limit weight-bearing to toe-touch only during this time and instruct the patient to walk with crutches.

• After 6 weeks, allow the patient to increase weight-bearing as tolerated, with very light hamstring concentric motion.

• Permit concentric strengthening after 8 weeks and eccentric strengthening at 3 months after surgery.

• At 3 months, allow the patient to begin light jogging, light short sprints, and closed-chain plyometric exercises.

• Sport-specific drills and activities should not begin prior to 4 months after surgery, with return to competitive sports after 6 months.

Results

Recently, a few case series have described the outcomes of patients undergoing endoscopic repair of proximal hamstring avulsions. Schröder et al. evaluated the outcomes of 12 patients with a mean follow-up of 25 months after endoscopic repair¹⁶. The authors reported an average visual analog scale (VAS) score of 0 (range, 0 to 2) and an average subjective hip value of 94%. Additionally, all patients were able to return to their original level of activity, and no postoperative complications, such as neuromuscular disorders, paresthesia, rerupture, or wound-healing disorders, were reported. More recently, Kurowicki et al. assessed the functional scores of 20 patients with a minimum follow-up of 1 year¹⁷. Postoperatively, the study group had satisfactory outcomes, with a mean VAS pain score of 1.85 ± 2.0, mean University of California Los Angeles activity score of 8.0 ± 2.0, and mean modified Harris hip score of 90.6 ± 10.5. Of the 20 participants, 3 reported persistent pain with sitting; however, 100% returned to work and 95% returned to sport.

Compared with the complications reported for patients undergoing open proximal hamstring repair, the endoscopic repair groups appear to have much lower complication rates. In a systematic review and meta-analysis, Bodendorfer et al. observed a complication rate of 23.2% among patients undergoing open repair of proximal hamstring avulsion, with approximately 8% having neurological complications; 5.2%, peri-incisional numbness; and 3.3%, infection or wound complications⁸. It is possible that complication rates are lower for endoscopic repair because of the absence of muscle retraction, as well as excellent visualization of the site of avulsion and subsequent repair from endoscopic magnification. However, it is also possible that complication rates for endoscopic repairs are lower because the technique is still gaining traction among surgeons and few studies have described outcomes of the procedure.

Pitfalls & Challenges

Preoperative

• Any sciatica symptoms during preoperative assessment or in chronic injuries indicate that there is potential nerve adherence to the avulsed tendon.

• Careful padding of all osseous prominences is needed to avoid the risk of pressure ulcers in the prone position.

Intraoperative

• Hypotensive anesthesia should be used to control bleeding.

• Optimal pump pressure is 30 to 40 mm Hg or as low as possible for good visualization with continuous outflow to avoid the risk of fluid extravasation, soft-tissue swelling, and compartment syndrome.

• Switch to an open procedure if there is severe thigh swelling, abdominal distention, or difficult tendon mobilization.

• Chronic injuries are more technically challenging than acute injuries because of anatomical distortion, tendon retraction, and tissue fibrosis.

• The optimal surgical timing is within 3 to 4 weeks after injury¹.

• Always identify the nerve prior to mobilization and fixation of the tendons to prevent iatrogenic nerve injury.

• Meticulous hemostasis throughout the procedure is essential to prevent the development of a hematoma.

Postoperative

• The function of the sciatic nerve must be addressed postoperatively. If hematoma with sciatic nerve irritation is present, revision with hematoma removal is indicated.