The Pipkin classification is a commonly used classification system for femoral head fractures. Pipkin IV refers to the anterior 3 types combined with acetabular fractures. Asghar et al. believe that this type of fracture needs surgery if it meets any of the following conditions: displacement of articular fracture surface > 1 mm, instability after joint reduction, and fracture range of acetabular wall > 20%; Wang et al. indicated that it is very important to restore the consistency and stability of the hip joint and remove small and comminuted intra-articular fractures as soon as possible. In addition, if the articular surface fracture of the femoral head cartilage is involved in the weight-bearing area, even small fracture blocks should be fixed and repaired. However, if the cartilage surface is defective or cannot be fixed, femoral head cartilage transplantation can reduce complications and obtain good results. Ahmed et al. A delayed reduction was associated with a higher rate of femoral head necrosis. Crock et al. noted that avascular necrosis of the femoral head is an important factor affecting the prognosis of femoral head fracture, which is closely related to the injury of blood vessels supplying the femoral head, especially the medial circumflex femoral artery. Therefore, surgery is recommended as soon as possible. Some scholars reported that the operation should be performed within 3 days after injury. The author's clinical data showed that early traction closed reduction of the hip joint and operation within 7 days after the injury did not increase the incidence of femoral head necrosis.
In this study, a limited S-P incision combined with a posterior K-L incision was used to treat Pipkin type IV fractures. The procedures are as follows: take the posterior K-L approach first, expose but not free the sciatic nerve to protect the sciatic nerve to the greatest extent, fix the fracture of the posterior wall of the acetabulum, protect (or repair) the joint capsule attached to the posterior wall of the acetabulum, determine the fracture position of the femoral head by rotating the lower limbs, and then take the distal part of the anterior S-P approach to fully expose and fix the fracture. Studies have shown that the distal part of the S-P approach is sufficient for the exposure and repair of femoral head fractures.
Operation details: (1) Because only the distal part of the S-P approach is selected, the stable structure in front of the hip joint can be protected to the greatest extent, and the stripping of muscle tissue can be reduced to lower the risk of ectopic ossification; (2) When the femoral head fracture block is reduced and fixed through partial S-P incision, the "4" position of hip flexion and abduction can be maintained to expose the anterior and inferior fracture block when the joint capsule and synovial tissue connected to it are protected to the greatest extent; (3) The partial S-P incision for femoral head fracture fixation keeps away from the branch of femoral head blood supply mainly by the posterior medial femoral circumflex artery (MFCA). Thus, the purpose of reducing the risk of femoral head necrosis may be achieved. (4) The exposure of the anterior approach is clear, which is conducive to the reconstruction of the femoral head with bone graft and the matching and fixation of the head and acetabulum. (5) Studies have shown that the sub-branch of the MFCA penetrates the bone cartilage junction of the femoral head along the posterior upper part of the femoral neck to nourish the femoral head. In the operation of the posterior approach, we tried to reduce the separation of the short external rotator muscle group, especially protecting the muscle group below the level of the external obturator muscle and the internal obturator muscle. Pay attention to the M-shaped incision of the joint capsule and avoid disturbing the synovial branch of the MFCA when resetting the posterior wall of the acetabulum. At the same time, without posterior reduction of the femoral head fracture, it also reduces the possibility of interfering with the MFCA and protects the blood supply of the femoral head.
At present, the commonly used surgical approaches for the treatment of Pipkin type IV fractures mainly include the simple Kocher-Langenbeck (K-L) and surgical dislocation of the hip joint (Ganz) approaches. The simple K-L approach has a wide exposure range and can address fractures of the posterior acetabulum and femoral head simultaneously, which is favored by many scholars. However, its surgical trauma is large, the incidence of complications such as vascular and nerve injury, avascular necrosis of the femoral head, and heterotopic ossification is high. It is difficult to reduce and fix under direct vision for anterior and inferior femoral head fracture blocks. Ganz et al. proposed the improved K-L approach in 2001, also known as the surgical dislocation of hip joint (Ganz) approach. This approach can protect the blood supply of the femoral head fully expose the fracture site and achieve complete reduction and fixation. It has obtained good curative effects treating Pipkin type IV fractures[17, 18]. However, the operation of this approach is complex, the learning curve is long, and the surgical trauma is large. The incidence of postoperative femoral head necrosis is 12.5%, and the incidence of ectopic ossification is as high as 20% ~ 60%[19–21]. At the same time, because this approach requires femoral greater trochanter osteotomy, there is a risk of nonunion of the osteotomy block.
There are relatively few cases of Pipkin IV fracture treated by the combined anterior and posterior approach. Ellis et al. have made relevant reports and agreed with its curative effect. Some scholars have conducted a 15-year follow-up study on a patient with a Pipkin IV fracture treated by a combined anterior and posterior approach and found that it can be used as an appropriate alternative method to treat Pipkin IV fractures under appropriate circumstances. Although it has been reported that the modified Gibson approach has the advantage of treating two parts of fractures with one incision simultaneously, two approaches from one incision have the disadvantage of mutual interference due to their close distance and may aggravate the damage to soft tissue. In this study, the exposition of fractures through two incisions increased some trauma, but it did not increase the traction injury of soft tissue, and the exposition was clearer. Our latest research also shows that the clinical effect of a direct anterior combined with direct posterior approach, which represents the idea of a combined approach, is also satisfactory.
Shortcomings of this study: To date, none of the patients in this group have serious surgical complications. However, the follow-up time of this study was 3 ~ 36 months, which is much shorter than the 81 months of Oransky et al.. Therefore, there is still the possibility of complications such as avascular necrosis of the femoral head and traumatic arthritis of the hip in the later stage of this group, which needs further follow-up observation. Meanwhile, in a few cases, there is no discussion of Pipkin type IV fracture with a femoral neck fracture, and there is also a lack of control study. Next, we will study all Pipkin type IV fractures, summarize appropriate treatment methods and reduce complications.