In order to achieve full flexion post-TKR, many factors, in addition to the surgical technique, should be addressed. Some of these factors can be controlled by the surgeon such as the implant design, surgical techniques, postoperative pain management, and rehabilitation. Other factors such as preoperative ROM, patient’s body mass index, and patient’s physical ability unfortunately cannot be controlled by the surgeon [6].

The implant design has the least direct effect on obtaining full flexion, and the implant is only useful in being more accommodating to full flexion. However, in order to accomplish full flexion in any patient, it’s important to remember that pain management and good rehabilitation program and multidisciplinary approach to the patient should be established in the hospital on a solid basis. Aggressive rehabilitation and adequate pain control are important in preventing postoperative contracture of the soft tissue and achieving better flexion [7].

We truly believe that surgical procedure is quite important to improve the ROM after TKR, and in this chapter, we will focus on quadriceps release technique. We still consider preoperative ROM has a great effect on the outcome of the TKR as many of the international studies so far claim that the ROM postoperatively averages the same as preoperatively [8]. However, in our series which are more than 6000 cases, we were able to obtain a better average ROM postoperatively compared to preoperatively. We consider that this is mainly due to the fact that we have performed routinely a modified quadriceps release (Tarabichi’s maneuver) in all our patients to increase the ROM intraoperatively [9]. In the literature, no one has discussed before the importance of the quadriceps release in achieving better flexion in TKR. The purpose of this chapter again is to discuss the anterior knee release and how to obtain a better flexion intraoperatively. Nevertheless, always be reminded that the other factors should be met in order to obtain a better ROM.

Quadriceps release has been used by sports medicine in order to increase the ROM. It is normally done through arthroscopy to increase the mobility for patients who suffer from posttraumatic and postsurgical knee stiffness. The stiffness is typically developed after a period of inactivity in the lower limbs [10]. It has been demonstrated that the restriction in ROM of stiff knee is frequently caused by adhesions that tether the distal quadriceps tendon and/or muscle to the bone surface, thereby preventing the quadriceps muscle and tendon from its normal excursion during flexion [11].

We have done analysis of knee movement; on average in order for the knee to bend from 0 to 90°, the quadriceps tendon normally stretches 6 cm which varies depending on femur size; the larger the femur, the more quadriceps stretching is needed to achieve the flexion (Fig. 12.2). The stretching of the quadriceps per 1° of knee flexion is more on the extreme ends of ROM. The quadriceps have to stretch 1.5 cm in order for the knee to bend from 135–155°; the average stretching is 0.7 mm per 1° compared to 0.4 mm per 1° in the ROM of 80–110°.

In our experience, as in the case of posttraumatic stiff knee, the anterior adhesions between the quadriceps muscle and the anterior surface of the femur are the main responsible factors for the restriction of ROM in the stiff arthritic knee. Therefore, we adapted our surgical techniques to address these adhesions and to improve the ROM in all our patients who undergo TKR (Fig. 12.3).

In another study, we performed 42 modified quadriceps muscle releases on patients with advanced osteoarthritis scheduled for TKR. The ROM was documented intraoperatively both before and immediately after the release. Passive flexion improved significantly in all patients (mean, 32.4° of improvement, P: 0.001) following a modified quadriceps release only, before doing any ligamentous release and excision of posterior osteophytes [9]. These results strongly suggest that adhesions of the quadriceps muscle to the underlying femur are the major factors which prevent the distal excursion of the quadriceps tendon, thereby preventing deep flexion in patients with osteoarthritis.

Our technique is a standard subvastus approach, initiated with an anterior midline skin incision. Once the extensor mechanism is mobilized, the underlying suprapatellar pouch can be identified and is subsequently excised along with any adhering bands or fibrotic tissue (Fig. 12.4a, b). Doing so provides direct access to the deep interface of the quadriceps muscle and the anterior surface of the femur, allowing the release to be carried out (Fig. 12.4c, d).