The concept of hip arthroscopy was first introduced by Burman in 1931, Gross reported the application of arthroscopy for the treatment of congenital hip dislocation in 1971, Vakliff and Warren reported the arthroscopic removal of cement blocks left from total hip replacement in 1980, and Holgersson et al. reported the use of hip arthroscopy for the diagnosis and treatment of juvenile forms of chronic hip osteoarthritis. The main reason for the relative lag in the development of hip arthroscopy is due to the fact that the development of hip arthroscopy is very different compared to that of knee arthroscopy. In the past decade, with the advancement of minimally invasive techniques, arthroscopic techniques have developed rapidly in the field of orthopedics, and hip arthroscopy has been rapidly developed for the diagnosis and treatment of hip disorders. Hip arthroscopy has provided an effective space for further exploration and understanding of hip disorders. Hip joint diseases that previously required incisional surgery, such as intra-articular free bodies and bone redundancy, can be accomplished under hip arthroscopy. The use of minimally invasive arthroscopic surgery can greatly accelerate the recovery time, which is incomparable to open surgery. Some lesions that were previously difficult to diagnose without arthroscopy can be operated on visually under arthroscopy. With the understanding of hip joint anatomy, the morphology and etiology of lesions in the hip joint will be greatly improved. Arthroscopic surgery provides us with a new set of diagnostic and treatment tools, and this technology will have a great impact on the future treatment.
I. Equipment and instruments
1. A routine spare C- or G-arm X-ray image intensifier is necessary to ensure accurate and unobtrusive access to the hip joint cavity.
2, 30 degree and 70 degree arthroscope, cold light source, camera imaging system, monitor arthroscope, manual instruments and electric cutting and planing system, radio frequency are necessary equipment. Generally, 30-degree arthroscopy is best for observing the central part of the acetabulum and the upper part of the femoral head and acetabular fossa. 70-degree arthroscopy is best for observing the peripheral part of the joint, the acetabular glenoid lip and the lower part of the acetabular fossa. The best images can be obtained by using them alternately.
3. Mechanical fluid pressure pumps are advantageous in maintaining water flow, as they may cause leakage of irrigation fluid if the water pressure is too high, and do not require high pressure to produce sufficient water flow.
4, a complete assortment of elongated arthroscopic cannulae, 4.5mm, 5.0mm and 5.5-mm in diameter, are specially designed and made for the dense and thick soft tissues around the hip joint, and standard arthroscopes can be used on these cannulae.
5, trocar, puncture cone arthroscopy with guidewire matching instruments, guidewire through a special 17-gauge 6-inch puncture needle into the joint.
6, conical trocar puncture cone in the prevention of injury than the tip of the three-bladed trocar needle is safer, often caused by puncturing the joint capsule when serious articular cartilage surface injury.
7.To adapt to the spherical surface of the femoral head, the elongated curved planing tool and the elongated slotted trocar are designed to create a channel for the curved tool, making the operation more convenient.
8.Specially designed elongated surgical instruments and specially elongated plasma knife help arthroscopic surgery operation.
II. Surgical methods
(A) Anesthesia and surgical position
1.General anesthesia or epidural anesthesia, sufficient blockage of motor nerve in order to ensure muscle relaxation.
2. Regardless of whether the supine or lateral position is adopted, the position must be appropriate, and the choice of position depends on the habit of the physician. Inappropriate position will make it difficult to perform the surgery. The advantage of supine position is that it is convenient to pose, much easier than lateral lying, and it only takes a few minutes to complete.
(b), traction supine position using a standard bone traction bed can be, without the need for those highly specialized, but not high use of traction equipment. It is easier to do an anterior approach in the supine position. An important advantage of the supine position is that fluid leakage can be avoided. Patients operated in the supine position are generally free of the serious complications described above.
Possible complications of the lateral approach are compression of the pubic nerve branches across the sciatic bone and strain on the sciatic nerve due to traction. Some people monitor the sciatic nerve intraoperatively with evoked potentials to determine that the pulling force should not be greater than 75 pounds and that the traction should not exceed 2 hours. Vertical perineal column flexion of the hip can greatly increase the traction force while straining the sciatic nerve, potentially causing sciatic nerve disuse. To protect the pubic nerve from injury, wrapping the perineal column well (at least 9 cm-12 cm in diameter) so that the hip on the surgical side is off to the side can effectively distribute the pressure on the perineum. The placement of the perineal pillar minimizes the risk of compressive perineal nerve palsy. A mild outward distraction is created by traction, which distances the contact point from the pubic nerve, disperses the external forces acting on the sciatic bone, and is well timed to reduce temporary nerve palsy. The patient lies supine on the traction bed and the flexion position allows the joint capsule to relax, but may strain the sciatic nerve or bring the sciatic nerve too close to the joint capsule. Therefore, hip flexion should be avoided during arthroscopic surgery. The lower extremity must be rotated to a neutral position intraoperatively, but the footplate should be free to rotate to ensure that the femoral head can be seen. The contralateral limb should be as abducted as possible, and an image intensifier can be placed between the legs. Light traction should be applied to the contralateral foot while immobilizing it to create a counter-traction force, which maintains the position of the pelvis on the surgical bed and keeps it from shifting due to traction on the affected side. The amount of traction applied to the limb and the degree of hip retraction can be further determined by fluoroscopy. A traction force of 25-50 pounds is required to distract the hip joint. If the joint is too tight, more force can be applied, but the increase in traction must be done carefully. If the joint does not open smoothly, traction can be continued for a few minutes to allow the joint capsule to adjust to the tension so that the capsule can relax and the joint can be opened without excessive traction. The vacuum shown on the fluoroscope is due to the negative intracapsular pressure after joint distraction. The joint can be retracted by injecting fluid into the joint to dilate the joint and open the sealed cavity. After confirming that the hip joint has been retracted, the traction weight should be reduced.
(iii) Preoperative body surface positioning draws the greater trochanter of the femur and marks the bony landmarks around the hip joint, vascular nerve pathways, arthroscopic and instrument entrances. The palpable bony landmarks around the hip joint are the greater trochanter and the anterior superior iliac spine. The deep bony landmarks are the femoral neck and acetabulum. After entering the hip joint, these deep bony landmarks can be explored with both the puncture needle and trocar needle.
(iv) Hip puncture is performed with an 18-gauge, 25-cm-long special puncture needle. The puncture needle is inserted along the apex of the greater trochanter of the femur and pierced into the hip joint along the acetabular rim. If the hip puncture is successful, the saline in the syringe attached to the puncture needle will automatically aspirate 10-15 ml into the hip joint cavity. fluid injected into the hip joint cavity will automatically reflux, indicating that the puncture needle is already in the hip joint cavity. The syringe is used to inject 10-15 ml of water into the joint to break the negative pressure aspiration seal in the joint, and the hip joint will relax and can be further retracted. The guide wire is inserted into the puncture needle, the puncture needle is withdrawn, and the guide needle is placed in place. A 5mm diameter hollow core-shaped arthroscopic guide rod is inserted along the guide needle into the joint cavity, and the arthroscopic puncture cone cannula is passed along the guide rod into the joint cavity. After the arthroscopic channel has been built, a working channel is established above the tip of the greater trochanter, directly over the anterior femoral head, with the instruments kept at a distance from the femoral head to avoid wear of the articular surface. After placement of the arthroscope, the anterior approach is completed under arthroscopic and x-ray surveillance. The puncture site of the hip capsule is directly visualized with a 70-degree arthroscope. Under the free edge of the anterior glenoid labrum, a 17-gauge lumbar puncture needle is first inserted into the joint cavity for exploration, and then the puncture cannula is inserted into and away from the articular surface of the femoral head.
(v) The surgical approach is generally three surgical approaches: anterior, anterolateral and posterolateral approaches. The femoral artery and femoral nerve are medial to the anterior approach, the lateral femoral cutaneous nerve is located close to the anterior approach, and the sciatic nerve is located posterior to the posterior lateral approach. The neurovascular course should be taken into account when determining the approach. Important anatomic structures near the lateral approach include the sciatic nerve posteriorly and the lateral femoral cutaneous nerve anteriorly. Anteriorly, there are femoral artery, femoral nerve and superior gluteal nerve away from the entrance, and their location should be noted to avoid injury.
1. Anterior approach The anterior superior iliac spine is located an average of 6.3 cm away from the anterior joint capsule and crosses the muscle belly of the suture and rectus femoris muscles before entering the anterior joint capsule. The lateral femoral cutaneous nerve is divided into three to four branches at the level of the anterior approach. The distance between the anterior approach and these branches is usually within a few millimeters. Because the nerve has multiple branches, it is inevitable that the nerve will be encountered when changing the position of the approach; however, nerve injury can be avoided by careful manipulation. Of particular note is that if the skin incision is too deep, it is easy to injure the cutaneous nerve branches. The anterior approach is almost perpendicular to the axis of the femoral nerve as it travels from the skin to the joint capsule, and is closer at the level of the joint capsule, with an average distance of 3.2 cm. The ascending branch of the lateral rotor femoral artery has some variation in relation to the anterior approach, but is generally located approximately 3.7 cm below the anterior approach. A terminal artery of this artery was confirmed by some cadaveric specimens at the level of the joint capsule, a few millimeters around the entrance. Care should be taken to prevent vascular injury from the anterior approach.
2. Anterolateral approach The anterolateral approach is established first, which is a safer approach. The anterolateral approach crosses the gluteus medius at the anterior edge of the lateral aspect of the joint capsule. In this area, the only structure that is closely related to the anterolateral approach is the superior gluteal cutaneous nerve that exits the sciatic fossa and travels laterally from posterior to anterior, passing through the deep surface of the gluteus medius. The nerve is located about the same distance from the anterior and posterior lateral approaches, with an average distance of 4.4 cm. anterolateral puncture is performed with a 6-inch-long 17-gauge puncture needle under x-ray guidance. when the puncture needle is inserted into the joint cavity, a vacuum usually occurs as the hip joint is distracted and fluid can be actively drawn into the joint cavity. it is confirmed that the puncture needle is in the joint capsule and 40 ml of fluid is injected to expand the joint cavity. The puncture needle often penetrates the acetabular glenoid labrum when entering the joint cavity via the anterolateral approach, and greater resistance to penetrating the glenoid labrum than the joint capsule can be appreciated when entering the needle. If the puncture needle penetrates the glenoid labrum, the simple treatment is to withdraw the needle after the joint has expanded and then re-enter the joint capsule below the level of the glenoid labrum. If this is not recognized, the trocar can cause glenoid labral injury. When the surgical instrument is inserted into the hip joint, it needs to pass through the gluteus medius and minimus muscles, and once it is inserted into the joint capsule, a definite “drop” sensation is felt. If bone is encountered before penetration into the capsule, the instrument is too far up against the outer wall of the acetabulum and too far down against the femoral head. The arthroscope and the inlet tube are connected, and the arthroscopic cannula is placed under direct arthroscopic vision and the synovial tissue that is hypertrophic, congested and edematous is cleared by planing or radiofrequency cavitation, and the cartilage debris that is floating is stripped away, and the cartilage trauma of the femoral head and acetabulum is repaired.
Anteroposterior fluoroscopy determines the location of the approach. When the lower extremity is rotated to a neutral position, the femoral head is tilted forward so that the center of the joint is located anterior to the center of the greater trochanter. The anterolateral approach is located at the anterior border of the greater trochanter and should enter anteriorly from the middle of the joint.
Due to the limitations of the anatomy of the hip joint and the thick and dense soft tissue envelope, carelessness can cause medically induced articular cartilage injuries. As long as one is familiar with the local anatomy around the hip joint, the nearby femoral nerve will not be injured. However, the course of the lateral femoral cutaneous nerve is very close to this approach. Care should be taken when making the incision and proper surgical technique can prevent injury to this nerve. The nerve can also be easily injured if the skin incision is too deep. If necessary, the arthroscopic surgery can be successfully completed using only two lateral approaches.
When establishing the posterior lateral approach, the puncture needle passes through the gluteus medius and gluteus minimus before reaching the posterior border of the lateral joint capsule and travels anteriorly above the pear-shaped muscle, adjacent to the sciatic nerve at the level of the joint capsule, with an average distance of 2.9 cm from the lateral border of the nerve. the arthroscopic lens is rotated backward to visualize the entry site below the posterior glenoid labrum. Establishing access under arthroscopic monitoring ensures that the instrumentation does not deviate or enter posteriorly, thus protecting the sciatic nerve from injury. Again, when doing a posterior lateral approach, it is important to ensure that the hip is in a neutral position. External rotation of the hip joint displaces the greater trochanter posteriorly. The greater trochanter is the main anatomical landmark, and if it is shifted posteriorly, it will increase the risk of injury to the sciatic nerve.
4.Lateral approach to the hip joint After general anesthesia or epidural anesthesia, the patient is placed in the supine position. The foot is fixed on the traction frame. The hip joint is placed in a mildly abducted, flexed and externally rotated position so that the joint capsule can be relaxed. The perineal pillar is placed against the perineal area between the legs, against the medial aspect of the affected thigh and pushed outward to create a mild outward counter-traction and to keep the perineal pillar away from the pubic nerve branches crossing the sciatic bone. A long puncture needle is inserted near the greater trochanter at the intended incision site to ensure accurate incision placement and that the incision is safer away from important vascular nerves. The branch of the lateral femoral cutaneous nerve is relatively close to the anterior incision but does not pose a risk to the nerve. Sufficient traction is applied to distract the hip joint by at least 12 mm and confirmed by x-ray fluoroscopy, and the traction force can be increased if necessary. After distraction of the hip joint, a long puncture needle is inserted through the anterior border of the greater trochanter and into the joint cavity over the femoral neck. There is a significant breakthrough sensation when penetrating the joint capsule, after which the acetabulum will block the entry of the puncture needle. At this point, an x-ray image intensifier is required to confirm the position of the puncture needle. If it has not yet entered the joint, it should be entered under X-ray fluoroscopy. The operator should adjust the video camera system so that the arthroscopic image that appears on the fluoroscopic screen corresponds to the image of the patient’s anatomic position, and the acetabulum can be seen directly through the lateral entrance. Once the surgical instruments have been inserted into the joint, the traction force is reduced to 50-75 pounds. When the traction force reaches a safer level, the joint remains drawn open because the muscles are already in a relaxed state.
If the acetabular rim and labrum cannot be visualized well at 30° arthroscopy, 70° arthroscopy can be used. Generally, after the joint capsule has been incised, it is easier to enter the joint with curved instruments if a slotted trocar is available. Curved surgical instruments can then be inserted along the slotted trocar. Once the curved instrument has been inserted into the joint through this trocar, the trocar is then removed to allow the instrument to move freely within the joint. Before removing the curved surgical instrument, the slotted trocar should be reinserted along it, which will ensure smooth access. In order to observe the circumferential and capsular portion of the hip joint, the arthroscope should be withdrawn backwards and then the traction pull should be reduced until the femoral head is back in the acetabulum.
The new radiofrequency ablation knife not only removes the synovial membrane, but also flattens the tissue. Clearing and removing the synovial tissue at the opening of the joint capsule provides a clearer view of the femoral head, neck and acetabular lesions. The surgical instruments and arthroscope can be interchanged at each entrance. Rotation, abduction, adduction, flexion and extension of the hip allow the surgeon to view the entire hip joint. While a large bone spur may block the anterior portal, the portal on the posterior aspect of the greater trochanter is not blocked and access to the hip joint can be gained through this portal without difficulty.
It has been found that the best way to use the posterior portal is to place the patient on his or her side. The arthroscope is inserted into the joint through the posterior portal and the hip is dilated by injecting fluid through the arthroscopic cannula. Using the anterior approach to the hip, the bone spur can be seen through the arthroscope. With the aid of an x-ray image intensifier, the surgeon can insert an electric planer under the spur and clear the soft tissue until the tip of the planer is visible. Once the motorized planer has created a gap, a radiofrequency ablation knife can be used to speed up the clearance process. A motorized grinding drill is then inserted to grind away the bone spur under direct vision, and once the bone spur is removed, an anterior access can be used.
Once the access is established, surgical instruments and arthroscopes can be interchanged in between to facilitate systematic examination of the hip and arthroscopic surgical manipulation. With the 30° and 70° arthroscopes, the medially and externally rotated hip can be visualized very accurately with the synovial membrane, the round ligament, and most of the anterior, posterior, and lateral surfaces of the glenoid labrum of the acetabulum and the weight-bearing articular surface of the femoral head in the upper weight-bearing region of the acetabulum. The anterolateral approach is best for visualizing the anterior acetabular wall and anterior glenoid labrum, the posterior lateral approach is best for visualizing the posterior acetabular wall and posterior glenoid labrum, and the anterior approach is best for visualizing the lateral glenoid labrum and the retroflexion of the joint capsule.
The lateral hip arthroscopic approach is safe and simple, and the instruments are easy to operate. The entire joint cavity can be observed with the arthroscope, and the surgical instruments can explore the entire joint. It provides a safe access for arthroscopic surgery. After the surgery is completed, the traction should be released immediately.
Third, the key to the success of surgical indications for hip arthroscopy lies in the selection of suitable cases. Although there are many indications, there are few patients with absolute indications.
In general, free body, glenoid labral tear, acetabular or femoral head cartilage lesion, ischemic necrosis of the femoral head, round ligament rupture or impingement, acetabular dysplasia, synovial disease, collagen disease (such as rheumatoid arthritis or systemic lupus erythematosus with impingement synovitis), crystalline hip arthropathy (such as gout, pseudogout), capsular contracture (such as Ehers- Danlos syndrome), synovial chondromatosis, blood disorders, infections, foreign body removal after total hip arthroplasty (diagnosis of occult infection, removal of intra-articular wire or cement foreign bodies), post-traumatic disorders (dislocation, Pipkin’s fracture), osteoarthritis, extra-articular disorders and intractable hip pain can be examined and treated by arthroscopic surgery. Patients with a history of trauma are better suited for arthroscopy, while patients without a history of trauma or with only mild trauma may have symptoms that indicate a joint more susceptible to injury or a degenerative process, in which case arthroscopic results may be less than optimal.
In addition, patients with symptoms such as strangulation and tingling are more likely to be candidates for arthroscopic debridement than patients with pain alone or those with limited motion due to pain. Hip arthroscopy may also be used in patients with long-term recurrent hip pain with persistent unrelieved symptoms and positive signs on examination but no clear diagnosis.
Patients with symptoms caused by a definite trauma are usually more suitable for arthroscopic surgery; if the patient’s symptoms are not obvious, the efficacy of arthroscopic surgery is difficult to predict. This is because, in the absence of a clear causative factor, there are often underlying pathogenic factors or degenerative pathologies that are difficult to completely reverse with arthroscopic surgery.
Arthroscopic surgery can be performed to relieve symptoms such as locking and sharp stabbing pain during joint movement. For pain during movement only, or even if the symptoms are not related to movement, arthroscopic surgery should be performed with caution, as the expected outcome may not be achieved after surgery. Hip pain in young people is often functional and may arise from soft tissue lesions within and around the hip, and most patients can improve function and reduce hip pain with conservative treatment. If persistent hip pain is not treated by rest, NSAIDs or physiotherapy, hip arthroscopy is of great value.
Fourth, contraindications to surgery hip arthroscopy is not a panacea for all joint disorders, it is very important to strictly grasp the indications for surgery and select patients appropriately. The following conditions are not suitable for hip arthroscopic surgery.
1, people with ankylosis and stiffness of the hip joint or contracture of the joint capsule, and diseases that limit joint retraction; 2, people with ectopic ossified joints that cannot be retracted or filled and cannot be accessed by arthroscopic instruments; 3, people with stress fractures of the femoral neck, incomplete fractures of the sciatic and pubic branches and severe osteoporosis; 4, people with obvious anatomical abnormalities of the hip bone and soft tissue caused by trauma or surgery; 5, people with progressive destruction of the hip joint, osteomyelitis, abscess formation or sepsis; 6, patients with skin disease or ulcers at the adjacent incision; 7, morbidly obese, difficult to reach the joint with instruments and difficult to operate.
V. Complications of surgery Hip arthroscopy complications are usually reported by doctors with more experience in arthroscopic surgery, while many serious problems that occur in beginners are not reported. Hip arthroscopy is much more difficult than knee arthroscopy, both in terms of access and technical operation, and attention should be paid to the prevention of surgical complications.
1. neurovascular strain injury Glick reported that in his early cases there had been temporary sciatic nerve palsy after traction. If a conventional approach is chosen and performed correctly, no vascular nerve will be injured because these structures are quite distant from the incision, and this is confirmed from an anatomical point of view. Flexion of the hip is generally not advocated when the hip is retracted. Flexion of the hip partially relaxes the joint capsule, but gives greater distraction to the sciatic nerve. Possible complications of the lateral approach are due to compression of the pubic nerve branch that crosses the sciatic bone by traction and to the strain on the sciatic nerve. The lateral femoral cutaneous nerve splits into three or more branches just before the arthroscopic entrance, one of which is immediately adjacent to the entrance. Therefore, care should be taken to avoid injury to this nerve when incising the skin. When a larger free body is removed from this exit, the need to enlarge the incision may cause nerve injury, some of which are transient paralysis of a branch, so special attention should be paid.
2, perineal crush injury Eriksson et al. reported a case of soft tissue necrosis of the perineum due to crush. We have encountered two cases of transient paresthesia of the pubic nerve, which was caused by compression of the perineal column in an orthopedic surgical bed. Proper use of traction equipment is important. When the hip joint is retracted, the traction weight and time should be minimized.
3, femoral head and glenoid labrum injury There is abundant soft tissue around the hip joint, and the joint cavity limits the operator’s use of surgical instruments. The cartilage surface of the femoral head is particularly vulnerable to injury during puncture. Damage to the glenoid labrum or cartilage may occur during the establishment of the access or during the operation. When establishing access, it is best to keep the puncture point below the glenoid lip and away from the articular surface of the femoral head.
4. Fluid leakage to tissues outside the joint capsule A large accumulation of fluid in the lateral position has been reported in the abdominal cavity and retroperitoneum, and transiently affected blood flow to the lower extremities, and even caused heart failure in some cases. It may be because of the potential danger of fluid leakage due to the accumulation of abdominal and pelvic fluid under the effect of gravity.
5. The effect of arthroscopic surgery on the blood supply to the femoral head is unknown, and there have been no reports of ischemic necrosis of the femoral head caused by arthroscopy, and no one has reported infection and venous thrombosis after hip arthroscopy. Despite this, these complications may still occur. Another common phenomenon is the occurrence of greater trochanteric bursitis near the lateral portal, which is more difficult to cure. Due to the thick soft tissues of the hip joint, which restrict the manipulation of surgical instruments, resulting in instrument breakage has occurred.