I. Concept of minimally invasive total hip replacement
Minimally invasive total hip replacement has clinical features such as small surgical incision, less blood loss, shorter hospital stay and faster recovery, but it can be divided into two categories in terms of minimally invasive concept. One category is to make the skin incision of traditional hip replacement surgery smaller, while the deep access and operation are almost the same as that of traditional surgery, and this type of surgery should be strictly called small incision total hip replacement. The incision and deep dissection of these procedures are unique and innovative, which emphasize the entry through the muscle gap without cutting the gluteus medius and external rotator muscles, and therefore are more in line with the true meaning of minimally invasive surgery.
At present, there is no consensus on the definition and criteria of minimally invasive total hip arthroplasty, but most scholars believe that minimally invasive total hip arthroplasty should have the following characteristics: first, the skin incision should be less than 8 cm; second, the operation should be performed through the muscle gap without cutting the muscle, and third, the hip capsule should be preserved.
Second, the introduction of various minimally invasive surgical methods
1.OCM anterolateral approach
This approach is characterized by entering from the muscle gap and preserving the hip capsule intact after surgery. The surgery is performed from the anterior border of the gluteus medius muscle into the hip joint, so the skin incision is also parallel to the anterior border of the gluteus medius muscle. Generally, patients can go to the ground on the third day after surgery and can be discharged after one week.
2.Double incision approach
Both the anterior and posterior incisions enter through the muscle gap, preserving the joint capsule, so it is also considered to be a truly minimally invasive technique. The anterior and posterior approaches to the hip have their advantages and disadvantages. The anterolateral approach exposes the acetabulum clearly and it is convenient to install the acetabular prosthesis, but it is more difficult to place the femoral stem prosthesis; the posterior lateral approach requires cutting the external rotator muscle, which exposes the acetabulum less than the anterior approach and increases the risk of dislocation after surgery, but it is easy to place the femoral stem prosthesis, so the anterior and posterior approaches are used to install the prosthesis separately.
3.Posterior lateral approach to the hip joint (modified Gibson incision)
The postero-lateral hip incision is the most commonly used incision because of its familiarity, and it is also the incision that was first tried in MIS and is one of the most reported accesses for MIS surgery at present.
It enters through the posterior border of the gluteus medius muscle, cutting off the posterior external hip rotators and the joint capsule to enter the joint. It is slightly difficult to reveal and install the acetabular prosthesis, but it is easy to place the femoral prosthetic stem. The disadvantage is that the surgery still requires cutting off the posterior external rotation structure of the joint, which destroys the stability of the posterior hip joint, and posterior dislocation of the hip joint is likely to occur after surgery.
Recently, the SuperPATH technique also adopts the postero-lateral approach and can be performed without severing the external rotators using special instruments, and the joint capsule can be sutured, which further shortens the recovery time of the patient and is gaining more and more respect. We carried out this technique in early 2015 and found that in addition to the advantages of small incision and quick recovery, the intraoperative bleeding was significantly reduced and the postoperative recovery time was significantly shortened because the external rotator muscle was not cut off.
4.Lateral approach to the hip joint (Hardinge incision)
The lateral hip incision is the approach used by a small number of scholars for hip replacement. It is mostly a straight incision centered on the greater trochanter. After the skin is cut, the broad fascial tensor muscle is cut in the direction of the incision, and the anterior 1/3 fibers of the gluteus medius muscle, the joint capsule and part of the attachment point of the lateral femoral muscle are peeled off from the trochanter, and the affected limb is rotated backward to one side to reveal the upper end of the femur and the acetabulum. The drawback of the operation is that the operation destroys the gluteus medius muscle, which stabilizes the hip joint, and it is easy to cause damage to the superior gluteal nerve, and individual patients may have claudication for a long time after the operation.
Special instruments required for minimally invasive total hip arthroplasty
Minimally invasive surgery has a small incision, and special instruments must be needed during the surgery, otherwise the surgery is very difficult. The required instruments include.
1.Special small semicircular acetabular contusion.
2.Acetabular tapper with eccentric distance.
3, femoral medullary enlarger handle with eccentric distance.
4, special acetabular pulling hook with light source.
5, television X-ray machine.
6, metal osteotomy plate on the lesser trochanter.
7, removable operating table.
8, sterilized leg cover, etc.
Fourth, the development prospect of minimally invasive total hip joint replacement technology
With the popularization of the concept of minimally invasive and the rapid development of minimally invasive technology in various fields of surgery, minimally invasive joint replacement has become a hot spot in orthopedics. Although there are still controversies, from the perspective of future development, minimally invasive joint replacement undoubtedly represents the trend of future development. The indications for minimally invasive total hip arthroplasty are mainly for first-time replacement, patients who are not overly obese and muscularly strong. It is not suitable for those who need revision, have internal fixation removed and those who need soft tissue release for hip flexion contracture, and should be performed with caution or enlarged incision for congenital hip dislocation, acetabular dysplasia, severe acetabular fracture and osteoporosis.
At present, scholars have points of disagreement on minimally invasive techniques, but there is also consensus on the following aspects.
1, Patient selection and preoperative education are very important.
2, Surgeons who perform minimally invasive total hip replacement need a clear learning curve, and the initial phase is a high complication period for inexperienced surgeons.
3. Minimally invasive patients have different anesthesia, postoperative analgesia, and rehabilitation than conventional surgery, which is also a topic that needs to be studied in the future.
4. Minimally invasive surgery must require special instruments, and both experienced doctors and special instruments are indispensable.
In conclusion, minimally invasive total hip replacement has been controversial for a long time, and the focus of the controversy is its value and significance. Theoretically, there should be no difference in the long-term effect between minimally invasive and conventional surgery, but minimally invasive surgery is more acceptable to patients and is the direction orthopedic surgeons strive to pursue.