Hamstring Anterior Cruciate Ligament Reconstruction with a Quadrupled or Tripled Semitendinosus Tendon Graft

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Chapter 16 Hamstring Anterior Cruciate Ligament Reconstruction with a Quadrupled or Tripled Semitendinosus Tendon Graft

Alberto Gobbi, Ramces Francisco

Introduction

A wide variety of techniques and graft types are now available for the reconstruction of the anterior cruciate ligament (ACL). Years of clinical and surgical experiences gained by surgeons together with the development and modification of the various instrumentations have greatly contributed to the better results currently reported in literature. However, disagreement persists among experts with regard to the ideal technique and graft type most suitable for reconstruction.

Currently, most surgeons use either the hamstring graft or the bone–patellar tendon–bone (BPTB) graft for ACL reconstruction. Previous studies have demonstrated the advantages and disadvantages of using one type of graft over the other. However, recent investigations have confirmed that comparable outcomes can be achieved with either of these two graft types.¹^–³

Inherent advantages cited with the use of hamstring grafts include its strength, decreased incidence of donor site morbidity, easier rehabilitation, smaller incisions, and better cosmesis.^1,^2,⁴ With BPTB graft, the strong bone-to-bone fixation and the faster healing achieved with the bone plugs at the graft’s end^1,⁵ remain important advantages.

In this chapter, we describe the technique of using a quadrupled semitendinosus tendon graft harvested with a bone block for the reconstruction of a torn ACL.

Studies have demonstrated that this type of graft configuration is capable of producing a clinically stable construct that allows recovery of normal limb strength and early return to active sports and results in low donor site morbidity.

Scientific Rationale for a Quadrupled Construct

Hamstring grafts have gained popularity among surgeons due to the well-documented higher donor site morbidity when patellar tendon graft is used.⁶^–⁸ Although prospective randomized studies comparing patellar tendon and hamstring grafts demonstrated no significant difference in final outcome, the apparent advantages offered by hamstring grafts remain appealing to surgeons. Previous concerns related to the hamstring tendon’s viability have long been dismissed, and studies comparing different graft types and configurations have demonstrated that failure load and stiffness values for four-stranded hamstring tendon grafts are higher than values reported for the natural ACL (2160N, 242 N/mm), 10-mm-wide patellar tendon grafts (2977N, 455 N/mm), and 10-mm-wide quadriceps tendon grafts (2353N, 326 N/mm).^9,¹⁰

On the other hand, concerns related to hamstring graft incorporation within the tunnel was addressed with Morgan’s ¹¹ introduction of an “all inside” technique using bone–hamstring–bone composite graft. Therefore to address the concerns related to morbidity and delayed graft incorporation, we developed a technique that combines the advantages of a decreased donor site morbidity by using only one hamstring tendon (semitendinosus) with the possibility of achieving faster graft–tunnel incorporation by including a bone block with the distal limb of the semitendinosus tendon during harvest.^1,^12,¹³

Surgical Technique

The surgery can be performed under spinal anesthesia or general anesthesia. The patient is positioned supine on the operating table, and the tourniquet is placed as high as possible on the thigh to allow sufficient distance from the exit point of the Beath needles in the lateral thigh. The tourniquet is inflated only during graft harvest. A thigh support is placed at the level of the tourniquet cuff while a foot bar is positioned at the end of the table to enable the knee to be fixed at 90 degrees of flexion during surgery while at the same time still allowing free range of motion.

A 3-cm vertical incision centered approximately 5 cm below the medial joint line, midway between the tibial tubercle and the posteromedial aspect of the tibia, is performed. The sartorial fascia is incised, and the semitendinosus tendon is dissected and detached proximally with a tendon stripper. The distal limb of the tendon is detached along with a tibial bone plug and periosteum with the use of an osteotome. To achieve the desired 7-cm quadrupled graft construct (2 cm inserted in the femoral tunnel, 3 cm intraarticular, and 2 cm inserted in the tibial tunnel), the required minimum tendon length would be 28 cm (range 28–30 cm) (Fig. 16-1). Alternatively, semitendinosus tendons that are shorter than 28 cm can be prepared in a tripled configuration.

Fig. 16-1 The semitendinosus tendon harvested with a bone block attached on one end. The ideal length for the graft should be at least 28 cm to allow the preparation of a quadrupled construct.

Graft Preparation

Quadrupled Semitendinosus Graft

At the back table, all the muscle tissues attached to the tendon are removed with the use of a curette. Once devoid of excess tissues, the tendon is folded in a quadrupled fashion with the bone plug tied outside. Prior to suture placement on the tendon construct, the depth of the femoral tunnel is measured to determine the appropriate size of the Endobutton-CL (Smith & Nephew, Endoscopy, Andover, MA) to be used. Once the proper size is chosen, the Endobutton is then positioned in the quadrupled construct’s end where the bone block is located. Both ends of the graft are then whipstitched using #5 nonabsorbable sutures. A polyester tape is then knotted at the other end of the graft (Fig. 16-2, A, B). Measurement of the graft diameter follows, using 0.5-mm increment sizers to match this with the diameter of the femoral and tibial tunnels. Once in place, the grafts are pretensioned and preconditioned prior to fixation with cyclical flexion and extension of the knee under maximum manual tension.^1,⁶

Fig. 16-2 Diagram (A) and actual quadrupled semitendinosus construct with Endobutton on one end and polyester tape in the other end (B). The bone block is positioned and stitched outside the graft.

Tripled Semitendinosus Graft (Alternative Option for Short Semitendinosus Grafts)

Harvested semitendinosus tendons with a total length of less than 28 cm can be prepared in a tripled configuration. Once the excess tissues are removed, both ends of the semitendinosus tendon are whipstitched using #5 nonabsorbable sutures (Fig. 16-3, A). The tendon is then folded in three parts (three limbs) to determine the graft’s length and to approximate the size of the Endobutton-CL to be used. In general, we usually use either a 20- or 25-mm Endobutton-CL, considering that we have a tunnel length of about 40 to 45 mm. On the end of the graft where the bone plug is located, the free ends of the suture are used to tie a knot around the Endobutton-CL so that it becomes attached to the graft (Fig. 16-3, B). The other end of the graft is then passed through the loop of the Endobutton-CL as the tendon is folded in three parts. After passing through the Endobutton-CL, the suture at the free end of the graft is separated and positioned in such a way that it would catch the looped tendon at the opposite end (Fig. 16-3, C). With this configuration the diameter of this tripled semitendinosus is measured to make sure that it corresponds with the femoral and tibial tunnels. Prior to the final fixation, routine pretensioning and preconditioning of the graft are performed.

Fig. 16-3 A, Diagram of the semitendinosus tendon with both ends sutured. B, Endobutton-CL is knotted on the end where the bone plug is located; the free end of the graft is then passed through the Endobutton-CL to form the three limbs. C, The free ends of the suture are separated and hooked around the opposite loop to complete the configuration.

Arthroscopic Anterior Cruciate Ligament Reconstruction

A standard anterolateral portal is created through which the arthroscope is inserted followed by an anteromedial portal where instruments can be introduced. While the graft is being prepared at the back table, tunnel preparations are completed. The tibial tunnel is prepared with the Acufex aimer set at 45 degrees with 70 degrees of inclination from the sagittal plane. During tibial tunnel reaming, a bone plug is obtained through the coring system used. On the other hand, the femoral tunnel is drilled in the 10:30 position for the right knee. Femoral fixation is achieved with the Endobutton connected to the graft while tibial fixation is obtained with an 8-mm titanium Fastlok device (Neoligaments, Leeds, United Kingdom), which is also connected to the graft with a quadrupled polyester tape. Finally, the bone block previously obtained from reaming the tibia is press-fitted in the tibial tunnel (Fig. 16-4). Postoperatively, rehabilitation is commenced according to the protocol described by Rosenberg and Pazik.¹⁴

Fig. 16-4 Diagram of quadrupled semitendinosus with bone (QSTB) anterior cruciate ligament reconstruction. Femoral fixation was achieved with a continuous loop Endobutton while tibial fixation was carried out with a Fastlok device augmented by a bone block impacted in the tibial tunnel.

Clinical Results

In a previous study ¹⁰ of 100 patients who underwent ACL reconstruction using this technique, it was demonstrated that the average postoperative VAS pain score was 5 (range 2–7), with 90% of the patients discharged within 24 hours following the procedure. This finding was consistent with the subjective IKDC scores in which an average rating of 80% was obtained. Six months following the procedure, 10% of patients had noted pain over the tibial hardware with associated hypoesthesia over the surgical incision. Clinical examination at final evaluation demonstrated 90 patients with less than 1 cm difference in thigh circumference, two patients with extension lag of 6 degrees, and another two patients with flexion loss of 10 degrees. Kneeling test was positive only in 7% of these patients, while the postoperative Lachman test was negative in 90% (+1 in nine cases and +2 in one case). Sensory changes were evident in 30% of patients at 3 months with only 10% having localized hypoesthesia at the proximal third of the tibia at final evaluation.

Subsequent radiographs and magnetic resonance imaging (MRI) revealed that only three tibial tunnels and four femoral tunnels were widened more than 25% from the original diameter. However, all these cases retained an anterior laxity that was less than 3 mm and subjectively rated their knees above 80%. MRI studies using T1- and T2-weighted transaxial sequences in 30 patients at 3 and 6 months demonstrated graft incorporation in the tunnels with evidence of viability.

Computerized analysis of knee laxity at final follow-up showed 90 cases to have a side-to-side difference of less than 3 mm, nine cases with 3 to 5 mm of difference, and one case with more than 5 mm of difference. The mean side-to-side difference was 1.9 mm (1.7 mm in males and 2.3 mm in females).

Isokinetic tests were not significantly different between 6 and 12 months (P = 0.6526). The hamstring/quadriceps ratio was slightly lower in the operated limbs compared with the normal limbs at all test intervals and speed settings but was not statistically significant (P = 0.9576). Neither external (P = 0.6181) nor internal rotation strength (P = 0.3681) demonstrated significant deficits at 6 and 12 months post-reconstruction when compared with the normal limb.

Knee evaluation scores demonstrated the following: IKDC (A, 66%; B, 24%; C, 9%; D, 1%); Noyes, 87.9 (range 65–100); Lysholm, 93 (range 70–100); and preinjury and postoperative Tegner, 6.1 and 6.0, respectively.