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’s¹¹ 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.