**5. Standard table**

Several advantages exist for the standard table in comparison to the Hana table. The ability to maneuver the legs allow for intraoperative assessment of leg length. The surgeon can directly manage the leg and no additional assistance is required to manage the table. In general, any operative table can be used that is radiolucent and allows for extension of the legs at the level of the hip joint. Regarding the surgical technique, there is no difference in the type of soft tissue releases between a standard or specialized table. The patient is positioned in a supine position with the hip joint at the level of the table break. It is necessary to hyperextend the operated hip during femoral preparation. Draping both lower extremities in a sterile fashion allows an intraoperative crossover of the operated leg for femoral exposure. The leg length discrepancy can be measured manually.

The muscle sparing anterior approach avoids release of the piriformis and obturator externus tendon. No specific hip precautions are needed and the patient is able to return to his or her normal activities after surgery without limitations [32]. The dislocation rate for the anterior THA is described in literature ranges between 0.6 and 0.9% [20, 21]. It is lower in comparison to those reported for other approaches; however, comparative studies have failed to show a consistent benefit [33, 34]. The senior author has no reported dislocations at all after perform-

Anterior Primary Total Hip Arthroplasty http://dx.doi.org/10.5772/intechopen.76070 113

Switching the surgical approach to an anterior THA is associated with a learning curve within the first 40–100 cases [35, 36]. Improvements in surgical and fluoroscopy times as well as differences in leg length have been reported during the learning curve [37, 38]. During the learning curve, it is recommended to carefully select patients. In general, preferred patients are

The anterior approach has some specific complications. These include LFCN injury and greater trochanteric fracture. Injury of LFCN is most commonly encountered during exposure and retraction. The nerve is located in the intermuscular-internervous interval between the sartorius and tensor fasciae latae muscle and is at risk if the incision is extended distally. Its course varies in different branching patterns and is at risk in approximately one-third of the patients during an anterior approach [39]. The risk of an injury can be minimized when staying inside the tensor fascia rather than the interval between the tensor and sartorius muscle [40]. LCFN neurapraxia occurs in approximately 0–5% of patients [41, 42]. None of the patients experienced any hip-related functional limitations, while most symptoms resolving

Muscle damage has not been considered a major problem due to the intermuscular nature of the approach [45]. Nevertheless, incorrect placement or retraction may cause damage. During capsular exposure the rectus femoris muscle is elevated and at risk. Attention while placing the retractors or using specialized retractors developed for the anterior THA can reduce the risk of soft-tissue damage. During femoral exposure the tensor is at risk for injury as well.

Cup alignment is challenging when performing an anterior THA due to limited view of the anterior acetabular wall. When inserting the reamer into the acetabulum, the anterior aspect of the femur might block its entrance. This may lead to an anterior shift of the reamer and can violate the anterior wall. Careful retractor placement and use of intraoperative fluoroscopy

Fractures might occur during femoral preparation, while manipulating on a specialized table [20]. Aggressive extension and external rotation of the femur using the table can result in a fracture of the tip of the greater trochanter secondary to tension of the conjoined tendon. Calcar fractures are the results of medial force on the calcar during broaching and can be fixed with cerclages (**Figure 14**). A rare complication, which might only occur when using a specialized

thin and younger females with elongated femoral necks and a type B Dorr Femur.

ing more than 500 THAs using an anterior approach.

**7. Challenges with the anterior approach**

after 6–24 months [37, 43, 44].

can minimize the risk associated with reaming.

If an anterior retractor is used, the bone hook is inserted with the femur in neutral rotation. Afterward the leg is placed in a figure 4 position (external rotation) to release the medial capsule down to the lesser trochanter. There is no difference in the soft tissue release technique; however, the piriformis usually has to be released in heavy male patients. The distal part of the standard table is extended to 40° allowing hyperextension of the operated hip as well as adduction and external rotation while positioning the limb crossing under the contralateral side.

## **6. Outcome**

Over the last couple of years, the anterior approach has become increasingly popular. Many advantages are described in comparison to the other approaches mentioned at the beginning of this chapter. Patients treated with the minimal invasive approach suffer less pain and consume fewer narcotics [25, 26]. This is usually explained by less soft-tissue damage while avoiding muscle splitting and detachment in comparison to the posterior or anterolateral approach.

An improved hip function and earlier return to normal gait are attributed to using an intermuscular and internervous interval [27, 28]. Rodriguez et al. have shown that patients reach certain milestones after an anterior THA earlier compared to a posterior THA. However, patients with a posterior approach had a similar result after 12 weeks [29].

The possibility of using intraoperative fluoroscopy when performing an anterior THA offers advantages over a posterior THA. The percentage of cup placed in the safe zone increases when using fluoroscopy routinely [6]. A higher precision and increased accuracy when implanting cup components can lead to a decreased dislocation rate [6, 21]. The anterior approach also improves relation of leg length and offset [7].

The majority of hip dislocations occur during the first 3 months after surgery. The healing of the posterior capsule and external rotator muscles release during a conventional posterior approach is considered the reason for early dislocation [30]. Hip precautions are recommended for 4–12 weeks to prevent any flexion and internal rotation after posterior THA [31].

The muscle sparing anterior approach avoids release of the piriformis and obturator externus tendon. No specific hip precautions are needed and the patient is able to return to his or her normal activities after surgery without limitations [32]. The dislocation rate for the anterior THA is described in literature ranges between 0.6 and 0.9% [20, 21]. It is lower in comparison to those reported for other approaches; however, comparative studies have failed to show a consistent benefit [33, 34]. The senior author has no reported dislocations at all after performing more than 500 THAs using an anterior approach.
