Anastomotic vascularized femoral medial epicondyle periosteal bone flap graft for non-union of navicular fracture
[Abstract
Objective: To investigate the clinical efficacy of an anastomosed intra-epicondylar femoral flap graft in the treatment of non-union of navicular fractures. METHODS: The feasibility of cutting the periosteal flap of the medial epicondyle of the femur was investigated through cadaveric anatomical studies. 7 cases of nonunion of navicular fractures were treated with this periosteal flap, and the clinical efficacy of this method was evaluated through long-term follow-up.
RESULTS: On the basis of familiarity with anatomy, the periosteal bone flap of the medial epicondyle of the femur was relatively easy to cut, and 7 cases were clinically applied, and as a result, 4 cases were excellent and 3 cases were good.
CONCLUSION: Anastomotic vascularized medial epicondylar femoral periosteal bone flap graft is a better method for the treatment of non-healing navicular fracture and is worthy of clinical promotion. Jia Xinlu, Department of Orthopedics, Liaocheng People’s Hospital
Fracture of the navicular bone is the most common wrist fracture, accounting for 51%-62% of all wrist fractures [1], and fresh fractures often occur due to the destruction of blood flow in the proximal part of the navicular bone, fracture omission or improper treatment, resulting in fracture nonunion; the incidence of fracture nonunion is as high as 13%-50% [2]. Seven cases of non-union of navicular fractures were treated with an anastomotic medial femoral epicondyle flap graft between May 2003 and May 2007, and good clinical results were achieved after follow-up:
1 Data and methods
1.1 Anatomy of application
The trophic vessels of the medial epicondylar bone flap come from the articular branch of the descending knee vessels or the superior knee vessels. The knee descending vessels are thicker, about 1.5-2 mm in diameter, and originate from the slightly proximal side of the medial wall of the femoral artery, which penetrates the fascia between the greater trochanter and the medial femoral muscle and divides into a deep branch and a superficial branch, with the deep branch reaching the periosteum of the medial femoral condyle and the superficial branch continuing to travel distally to the underside of the patella. The vessels originate from the medial wall of the N artery at the level of the superior border of the medial femoral condyle, travel deeper in the semitendinosus and semimembranosus muscles to the underside of the medial femoral membrane, and then enter the skin of the medial femoral epicondyle and the medial superior region of the patella between the medial femoral muscle and the suture muscle. The descending knee vessel branches off from the knee to nourish the skin of the medial superior knee and medial calf, and this vessel can be used to design a flap to monitor the blood flow of the osteochondral flap.
1.2 General information
There were 7 cases in this group, 6 males and 1 female, aged 16-40 years old, with an average of 24 years old. There were 5 cases on the dominant side and 2 cases on the non-dominant side. There were 5 cases of lumbar fracture and 2 cases at the proximal 1/3. The injury time from the time of consultation was 3-20 months, with an average of 9 months. The clinical manifestations were: painful wrist movement, aggravated by dorsal extension and radial deviation in 7 cases, limitation of wrist movement, and pressure pain at the nasal fossa in 6 cases. x-ray showed resorption of the fracture end in 7 cases, cystic changes in 3 cases, sclerosis and cystic changes at the same time in 2 cases, and ischemic necrosis of the proximal end of the fracture in 5 cases. all 7 cases had obvious displacement of the fracture end and hunchback deformity. 2 cases had a history of failed Rusee cancellous bone grafting. 3 cases had been diagnosed as navicular fracture and were fixed in a cast. All three cases showed ischemic necrosis of the proximal segment of the navicular fracture on preoperative MRI.
1.3 Surgical method
Under general anesthesia, the upper limb of the affected side was abducted, and the bone flap of the contralateral lower limb was taken slightly posterior to the medial midline of the distal 1/3 of the contralateral femur, and the cryptic branch of the descending knee vessels and its position through the deep fascia to the subcutis were marked with Doppler, and a tourniquet was installed for backup. The affected limb and the contralateral medial femoral epicondyle were disinfected and toweled at the surgical field where the bone flap was taken.
The radial palmar incision was made along the radial flexor carpi radialis tendon, and a 5-cm-long incision was made along the radial stem to reveal the radial stem. The radial stem was excised to fully reveal the navicular bone and fracture end, and the fibrous granulation tissue and a small amount of sclerotic bone were cleared from the fracture end to determine the blood flow to the fracture end. A bone groove of approximately 10 mm × 6 mm × 4 mm was created across the fracture end on the palmar side of the navicular bone using a special bone knife and a grinding drill. The radial artery and cephalic vein were temporarily removed from the nasal fossa to preserve their continuity and set aside.
A longitudinal incision of approximately 15 cm in length was made at the medial epicondyle according to the location of the cryptic branch marker, and the cryptic branch of the descending knee vessels was found subcutaneously and the flap was cut at its center, measuring approximately 3 cm × 2 cm. The medial femoral muscle was separated from the greater trochanter to reveal and free the descending knee vessels from the femoral artery to the medial epicondyle of the femur. The large branches of the descending knee vessels are searched for so that an embedded vascular anastomosis can be performed. The distribution of the terminal branches of the descending knee vessels in the periosteum of the medial femoral epicondyle is fully exposed, and the periosteal flap is designed at the medial femoral epicondyle according to the size of the navicular bone groove, avoiding the medial collateral ligament and the joint capsule, and the periosteal flap is first cut with a scalpel and then chiseled down with a sharp bone chisel, taking care not to separate the periosteum from the bone. After the blood flow is proved to be normal, the knee descending vessels are ligated and cut off at the femoral artery, and the osteocutaneous flap is cut. If the descending knee vessels are too thin (<1 mm), they can be replaced by the superior knee vessels. To protect the blood flow of the flap, the flap is carefully trimmed to fit into the navicular sulcus with an occlusal forceps. The bone flap is embedded in the navicular sulcus and fixed in the navicular sulcus with 1-2 1mm kerf pins, and the artery of the descending knee vessel is embedded or end-to-end anastomosed with the radial artery, and the vein of the descending knee vessel is end-to-end anastomosed with the cephalic vein, respectively, under the microscope, and the flap is set in the skin incision for observation of bone flap blood flow. The wrist incision was sutured. The super elbow cast was fixed to the wrist in the functional position for 3 weeks and then changed to the inferior elbow cast for another 2 weeks. The kyphosis pin was removed at 3-4 months depending on the fracture healing. Routine postoperative anticoagulation and antibiotics were administered for 7 days.
2 Follow-up results
The follow-up period was 8 months-3 years with an average of 12 months. All 7 cases were monitored for normal flap blood flow and good flap survival. 7 cases obtained bony healing within 8 months after surgery, and the humpback deformity disappeared or basically disappeared after fracture healing. The wrist movement pain disappeared or was reduced, and all wrist movements were significantly improved compared with before. No osteoarthritis appeared. According to the functional judgment criteria of Liu Shuqing et al [3], 4 cases were excellent and 3 cases were good.
3 Discussion
3.1 Treatment methods and advantages and disadvantages of non-healing wrist navicular fractures
Most navicular fracture fracture nonunion can be treated by the traditional Russe cancellous bone graft method, and the fracture healing rate can generally reach 75%, with the advantages of easy surgical operation and convenient bone grafting, etc. However, there is still a high rate of fracture nonunion due to graft resorption and proximal ischemic necrosis of the fracture [4]. Various live bone grafts with vascular tips can promote fracture healing because they can avoid graft resorption, facilitate the establishment of blood circulation in the ischemic necrotic proximal fracture segment, and accelerate the osteogenesis of the fracture end. Commonly used are the bone flap of the radial stem of the return branch of the radial artery [5, 6], the bone flap with the anterior rotator muscle as the tip, and the bone flap of the first metacarpal with the dorsal vessels of the thumb as the tip. The above bone flaps with fascial tips are short, and due to the restricted rotation, it is difficult to implant bone flaps from the metacarpal side of the navicular bone to correct the hunchback deformity of the navicular fracture. The anastomotic bone flap graft can overcome the above disadvantages. It has the advantages of constant vascular anatomy, convenient cutting and extraction, and small trauma to the bone site. The deep iliac artery-tipped iliac flap is less commonly used to treat short bone fractures that do not heal because of the difficulty of cutting, trauma, and the small size of the flap required for shaping. Compared with the tipped flap, the anastomosed medial epicondylar femoral flap still has the disadvantages of adding a knee incision, large trauma, relatively complex operation, and higher microsurgical technique requirements, so the indications for this procedure need to be strictly controlled.
3.2 Indications for medial epicondylar femoral bone flap for non-union of navicular fracture
The indications for medial epicondylar femoral flap grafting for nonunion of navicular fractures are controversial [7]. We believe that the following indications are available: i. X-ray shows sclerosis and cystic changes at the fracture end of the navicular bone, and MRI shows ischemic necrosis in the proximal segment of the fracture. II. Failure of conventional Russe cancellous bone grafting (fracture still not healed 1 to 2 years after surgery). III. Intraoperative confirmation of cystic degeneration at both ends of the fracture, cleanup of the distal section of the fracture without punctate hemorrhage, and confirmation of ischemic necrosis in the proximal fracture segment. IV. The operator has solid microsurgical skills. V. The patient agrees to perform the procedure.
3.3 On the cutting of the bone flap
In order to monitor the postoperative blood flow of the flap, the cryptic branch of the descending knee artery should generally be removed at the same time. For this reason, preoperative ultrasound Doppler should be used to locate the travel position of the cryptic branch of the descending knee artery in order to reduce the blindness in removing the flap, which is usually located slightly posterior to the medial midline of the distal 1/3 of the thigh. The descending knee vessels are located between the vastus lateralis and the medial femoral muscles, and are observed for their diameter, which sometimes varies. When freeing the tip of the vessel, it should be as close as possible to the femoral artery or N artery, and after finding the branch of the vessel, the vessel should be cut off near the bifurcation of the vessel in order to perform an embedded vessel anastomosis, and if a large branch of the descending knee vessel cannot be found, an end-lateral anastomosis should be performed to prevent damage to the blood flow of the hand.