Anterior Cruciate Ligament Reconstruction Using a Bone–Patellar Tendon–Bone Autograft to Avoid Harvest-Site Morbidity in Knee Arthroscopy

Abstract

Although anterior cruciate ligament reconstruction using a bone–patellar tendon–bone (BPTB) autograft has many advantages (e.g., high strength and solid fixation), there are also several complications (e.g., anterior knee pain or kneeling pain) due to harvest-site morbidity associated with the use of this graft type compared with the use of hamstring tendon. Therefore the ultimate goal of anterior cruciate ligament reconstruction using a BPTB graft is to minimize harvest-site morbidity. We have used a technique for harvesting central-third BPTB grafts that involves only a 3-cm-long, longitudinal, curved incision in the medial tibial tuberosity for both graft harvesting and fixation. The purpose of this report is to describe the technique, which can avoid the harvest-site morbidities associated with BPTB autografts during knee arthroscopy. We believe that this less invasive reconstruction may reduce the harvest-site morbidities associated with BPTB grafts because it allows for BPTB graft harvesting without incising the synovial bursa or paratenon and mitigates scarring and adhesion formation.

Anterior cruciate ligament (ACL) ruptures are among the most frequent ligament injuries. Given that obtaining sufficient regeneration is difficult in cases of a torn ACL because of its poor healing potential, reconstruction surgery is the first choice for treatment of ACL ruptures. Thus bone–patellar tendon–bone (BPTB) and hamstring tendon (HS) autografts are the 2 most commonly used reconstruction techniques. In 1963 Jones¹ pioneered the use of BPTB grafts, and this technique has since been considered the gold-standard technique. The BPTB graft is most frequently used because it provides high strength and stiffness, graft size consistency, harvesting ease, early graft incorporation, and solid fixation. However, reconstruction using a BPTB graft is not a perfect solution and may result in harvest-site morbidities, including anterior knee pain or kneeling pain. To avoid the harvest-site morbidities associated with BPTB grafts, HS grafts have recently been used for ACL reconstruction²; however, they are associated with graft loosening, require more expensive implants, and have the potential for knee flexion weakness. In fact, many surgeons who regularly use HS grafts advocate the use of BPTB grafts in athletes and heavy laborers.³ We believe that the ultimate goal of ACL reconstruction, using a BPTB graft, is to minimize harvest-site morbidity.

We have successfully used a technique for harvesting central-third BPTB grafts that involves only 1 longitudinal, curved incision, approximately 3 cm in length, in the medial tibial tuberosity for both graft harvesting and fixation. This technique, performed using devices previously developed by us, not only involves a small skin incision but also allows for BPTB graft harvesting without incising the synovial bursa or paratenon. Subsequently, the BPTB graft can be fixed through the same incision using an all-inside technique. In this report we describe our technique, which may avoid the harvest-site morbidities associated with BPTB grafts.

Technique

Arthroscopy routinely precedes ACL reconstruction, and additional procedures, such as meniscal repair, partial meniscectomy, synovectomy, and removal of chondral fragments, are performed when required. We use an Alvarado surgical knee holder (Zimmer, Tokyo, Japan) for harvesting the ipsilateral BPTB graft, with the knee flexed at 90°.

Graft Harvesting

A central-third BPTB graft can be obtained without incising the synovial bursa or paratenon using the instruments (Ario Medical, Osaka, Japan) shown in Figure 1.

Fig 1.

Surgical instruments (Ario Medical): (A) guide plate, (B) scalpel blade, (C) scalpel holder, (D) bone fragment harvester, (E) drill holder, and (F) trephine drill.

Skin and Paratenon Incision

A longitudinal, curved incision, approximately 3 cm in length, is made above the medial tibial tubercle. The paratenon is exposed and incised in the transverse direction (Fig 2A), with a width of 2.0 cm, at the level at which the patellar tendon is attached to the tibial tubercle (Tables 1 and 2, Video 1). The paratenon detachment from the patellar tendon is extended from the incision toward the distal third of the patella, using scissors.

Fig 2.

Surgical procedure involving left knee, flexed at 90° (the insets in some panels are lateral radiographs, taken under fluoroscopic guidance). (A) Skin and paratenon incision. The paratenon is exposed and incised in the transverse direction. (B) Guide plate fixation. The tibial side of the guidewire is fixed using a K-wire. (C) Cutting of patellar tendon. The patellar tendon is incised between the paratenon and patellar tendon by pushing the tendon cutter (scalpel holder and blade) along the guide plate. (D) Detachment of tibial bone fragment. A soft wire is inserted through the tibial bone fragment and is doubled up. (E) Detachment of tissue attached to patellar tendon. The detached tibial bone fragment and patellar tendon are pushed through the bone fragment harvester. (F) Preparation to detach patellar bone fragment. A large beak of the drill holder is hooked on the already fixed K-wire above the patella. (G) Cutting of patellar bone. Osteotomy of the patellar bone is performed using the trephine drill after hooking the large beak of the drill holder. (H) Detachment of patellar bone fragment. The bone fragment harvester is advanced from the bottom to the center of the patella. (I) Bone–patellar tendon–bone (BPTB) graft release. The BPTB graft is completely harvested.

Table 1.

Advantages and Risks of Procedure

Advantages

Avoids harvest-site morbidities

Decreases potential for injury to neurologic structures

Allows improved cosmesis (small skin incision)

Risks

Intraoperative patellar fracture

Mismatched harvesting (non-straight tendon or small bone fragment)

Table 2.

Graft Harvesting to Avoid Harvest-Site Morbidities

Indication

All patients with symptomatic anterior cruciate ligament insufficiency

Procedural summary

1. A longitudinal, curved incision (approximately 3 cm long) is made above the medial tibial tubercle.

2. The paratenon is exposed, incised in the transverse direction, and detached.

3. A K-wire (first K-wire) is inserted above the patella.

4. A guide plate is inserted between the paratenon and patellar tendon and is hooked to the K-wire.

5. The guide plate is distally fixed using another K-wire (second K-wire).

6. The patellar tendon is cut using a tendon cutter, preserving the paratenon.

7. The second K-wire and the guide plate are removed.

8. The tibial bone fragment is detached using a bone saw, and a soft wire is inserted through the tibial bone fragment.

9. The soft wire is passed into a bone fragment harvester, and the detached tibial bone fragment and patellar tendon are pushed through the bone fragment harvester.

10. The detached tibial bone fragment and patellar tendon are pushed through a drill holder.

11. A trephine drill is inserted into the drill holder and pushed to the bottom of the patella.

12. The small beak of the drill holder is driven to the bottom of the patella and immobilized.

13. After removal of the drill holder and trephine drill, the bone fragment harvester is advanced to the bottom of the patella.

14. The bone–patellar tendon–bone graft is harvested by twisting the patellar bone fragment.

15. The first K-wire is removed.

Fixation of Guide Plate

A Kirschner wire (1.5 mm in diameter) is inserted above the proximal-third of the patella. A guide plate (Fig 1A), having the same width as the BPTB graft to be harvested, is inserted between the paratenon and patellar tendon, and the bifurcated tip on its patellar side is hooked to the K-wire. The guide plate is placed in the center of the patellar tendon, and its tibial side is fixed using a 2.0-mm-diameter K-wire inserted into a hole on the guide plate (Fig 2B). This maneuver allows the guide plate to be precisely fixed above the patellar tendon to be incised.

Cutting of Patellar Tendon

A scalpel blade (Fig 1B), having the same width as the guide plate, is mounted on a scalpel holder (Fig 1C), and the scalpel holder and blade (termed a “tendon cutter”) are applied to the immobilized guide plate. The tendon cutter has 3 different possible widths: 9.0, 10.0, and 11.0 mm. A 9.0-mm-wide blade is used for patients whose height is 165 cm or less; 10.0 mm, for patients whose height is 166 to 175 cm; and 11.0 mm, for patients whose height is 176 cm or more. The patellar tendon is incised between the paratenon and patellar tendon by pushing the tendon cutter along the guide plate (Fig 2C). The tendon cutter is advanced in a straight line, with the guide plate serving as a rail, and the K-wire is held in the groove of the scalpel holder. This method results in an accurate incision of the patellar tendon; thereafter the tendon cutter, guide plate, and 2.0-mm-diameter K-wire are removed.

Detachment of Tibial Bone Fragment

The tibial bone fragment is detached using a bone saw. An 80-cm-long soft wire, with a diameter of 0.9 mm, is inserted through the tibial bone fragment and is doubled up (Fig 2D).

Detachment of Tissue Attached to Patellar Tendon

The soft wire is passed into a bone fragment harvester (Fig 1D), and the detached tibial bone fragment and patellar tendon are pushed through the bone fragment harvester, which is advanced into the patellar tendon while the soft wire is being pulled (Fig 2E). This maneuver allows detachment of the tissue attached to the patellar tendon. The bone fragment harvester also has 3 different possible diameters: 9.0, 10.0, and 11.0 mm.

Preparation to Detach Patellar Bone Fragment

The detached tibial bone fragment and patellar tendon are pushed through a drill holder (Fig 1E), and the large beak at its tip is hooked to the K-wire initially fixed above the patella (Fig 2F).

Cutting of Patellar Bone

A trephine drill (Fig 1F) is inserted into the drill holder and pushed to the bottom of the patella while the soft wire, under continuous tension, is pulled to the patellar tendon. In this state the small beak of the drill holder is driven to the bottom of the patella and immobilized. With the soft wire being pulled by an assistant and the drill holder being immobilized by the surgeon, osteotomy of the patellar bone, excluding the proximal end of the BPTB graft, is performed using the trephine drill (Fig 2G). As a result, the cross section of the osteotomized patella is D-shaped.

Detachment of Patellar Bone Fragment

After removal of the drill holder and trephine drill, the bone fragment harvester, with a shape matching the osteotomized patellar cross section, is advanced to the bottom of the patella (with the soft wire being pulled by the assistant) and further to the center of the patella (Fig 2H).

BPTB Graft Release

The proximal end of the BPTB graft is detached by twisting the tail of the bone fragment harvester thrice; the soft wire is not pulled during this maneuver. Finally, the BPTB graft is harvested completely (Fig 2I), and the 1.5-mm-diameter K-wire is removed.

Creation of Tibial and Femoral Tunnels

A tibial tunnel is established using a Pinn-ACL Tibial Guide (ConMed Linvatec, Largo, FL), positioned at a 45° angle to the bone. A guidewire is first inserted from the medial side of the tibial tubercle, at a 45° angle, under fluoroscopic guidance, and a tibial tunnel, with a diameter equal to that of the BPTB graft, is endoscopically drilled over the guidewire. The resident's ridge is visualized on the lateral wall, and a femoral tunnel is created behind the resident's ridge through the tibial tunnel; notchplasty is performed when necessary. A Bullseye Femoral Off-Set Guide (ConMed Linvatec) is used to insert the guidewire into the ACL femoral footprint; this guidewire is positioned 7.0 mm forward from the over-the-top position at the 10- to 11-o'clock location of the intercondylar notch (right knee) or the 1- to 2-o'clock position (left knee), under fluoroscopic guidance. A femoral tunnel, with a diameter equal to that of the BPTB graft, is also endoscopically drilled, up to 40 mm in length, over the guidewire. The length of the femoral tunnel is measured using a depth gauge.

Graft Preparation and Fixation

Each bone fragment is trimmed to its appropriate diameter. On the femoral side, 2 No. 5 Ti-Cron sutures (Covidien Japan, Tokyo, Japan) are passed through the drill holes, along with an EndoButton (Smith & Nephew Endoscopy, Andover, MA), with a 15-mm loop, according to the measured length of the femoral tunnel. The EndoButton is connected to a passing pin (Smith & Nephew Endoscopy) using a No. 5 Ti-Cron suture and a No. 2 Vicryl suture (Johnson & Johnson, Tokyo, Japan). On the tibial side, two 30-cm-long soft wires (diameter, 0.9 mm) are inserted through the 2 holes in the tibial bone fragment and are doubled up (Fig 3A). During arthroscopy, the BPTB graft is introduced from the tibial tunnel to the femoral tunnel, using the passing pin, and the EndoButton is flipped and fixed to the femoral cortical surface, under fluoroscopic guidance (Fig 3B). An interference screw (Zimmer) is used for graft fixation on the tibial side, at 90° of knee flexion, while manual tension is maintained on the soft wire with the BPTB graft. Then, the 2 soft wires are removed. The tibial bone defect at the donor site is filled with cancellous bone, which is collected after reaming of the tibial tunnel. With the tendon defect left open, the soft tissue is closed over the donor site, layer by layer.

Fig 3.

(A) Bone–patellar tendon–bone (BPTB) autograft. (B) Arthroscopic view from anterolateral portal of left knee. The BPTB graft tension is confirmed with a probe.

Postoperative Management

Immediately after surgery, the knee is immobilized, in full extension, using a cast for the first postoperative week. Patients begin active quadriceps isometric exercises on the first postoperative day and begin passive-motion exercises using a continuous passive-motion machine at 1 week, after swelling mitigation. At the same time, they are placed in a knee brace adjusted to allow full flexion; the knee brace is worn for 8 weeks. At 2 weeks, patients are allowed to walk with partial weight bearing; at 3 weeks, full weight bearing is allowed as tolerated. At 4 weeks, active muscle-strengthening exercises are started, and jogging is permitted at 4 months; unrestricted return to full sports activities is allowed 7 months after surgery.

Discussion

Harvest-site morbidity is the most important concern during ACL reconstruction using a BPTB graft. In the 13 published randomized controlled trials comparing BPTB and HS grafts,^4-16 BPTB grafts were associated with a higher incidence of anterior knee pain or kneeling pain. However, harvest-site morbidities occurred with both HS and BPTB grafts, suggesting that these complications are not inherent to BPTB grafts. Many studies have shown that BPTB grafts result in kneeling pain more frequently than do HS grafts (range, 36% to 84% v 19% to 53%).^{5,7,9,12,13,16,17} However, some studies could not detect a significant difference in the incidence of anterior knee pain associated with BPTB versus HS grafts (range, 16% to 43% v 7% to 33%).^4-9,11 Furthermore, one study has shown that BPTB autografts have an advantage because the allograft group had a failure rate 15 times greater than that in the autograft group.¹⁸ Thus, diminishing the harvest-site morbidity associated with BPTB autografts is necessary.

Some authors have recommended the use of a double incision for harvesting BPTB autografts because of the cosmetic advantage and/or reduced risk of potential nerve injury.^19-21 Kartus et al.²⁰ compared the use of the traditional technique and the double-incision technique to protect the infrapatellar nerves and paratenon and reported that the double incision significantly decreased the risk of anterior knee pain. In response to the vertical double incisions recommended by Kartus et al., Tsuda et al.²¹ advocated a horizontal double-incision harvesting technique because the horizontal incisions decreased the risk of potential injury to neurologic structures. Regardless, harvesting the graft without incising the synovial bursa or paratenon is crucial for decreasing harvest-site morbidity. We harvested the BPTB graft using a single incision, through the tuberosity, and the BPTB graft was fixed through the same incision using an all-inside technique, which resulted in lower visual analog scale pain scores.²² This technique allowed the BPTB graft to be harvested without longitudinally incising the synovial bursa or paratenon. Therefore the paratenon remains as a barrier for preventing the spread of inflammation or hematoma, and this tissue-friendly procedure also mitigates scarring and adhesion formation. Helpful tips and pearls for the procedure are listed in Table 3.

Table 3.

Tips and Pearls for Anterior Cruciate Ligament Reconstruction Using Bone–Patellar Tendon–Bone Autograft to Avoid Harvest-Site Morbidities

Keep the knee positioned for graft harvesting.

Use lateral fluoroscopic guidance for graft harvesting.

Do not longitudinally incise the synovial bursa or paratenon.

Carefully use instruments for graft harvesting.

Use an arthroscopic all-inside technique for creation of tibial and femoral tunnels and for graft fixation.

In summary, this technique seems to be safe and allows for diminishing harvest-site morbidity. However, the technique requires a detailed evaluation and further follow-up to confirm its apparent reliability. We advocate the use of this technique as a less invasive reconstruction method for all patients with ACL ruptures.

Supplementary Data

Video 1

Technique for harvesting a central-third bone–patellar tendon–bone (BPTB) graft in a left knee, flexed at 90°. This technique involves only a small skin incision that also allows for BPTB graft harvesting. This procedure may reduce the harvest-site morbidities associated with BPTB grafts.