With the increase of human life expectancy, the aging of the population has led to an increasing number of osteoporosis (OP) and fractures caused by it, which seriously threaten the health of middle-aged and elderly people. According to the epidemiological research results of China’s “Ninth Five-Year Plan” project, the total prevalence of OP and low bone mass in China is 22.6% and 13.3% respectively. Meanwhile, the total prevalence of osteoporotic fracture among people over 50 years old is 26.6%, of which 24.6% are men and 28.5% are women.
At present, surgery is mostly advocated for patients with osteoporotic fractures that can tolerate surgery, but how to properly assess the status before surgery, how to improve the stability of internal fixation and postoperative rehabilitation to prevent re-fall are gradually becoming concerns. This paper reviews the current status of research on the selection of surgical treatment for osteoporotic fractures, strengthening of internal fixation and postoperative rehabilitation.
1.Surgical treatment of osteoporotic fracture
Patients with osteoporotic fractures have a reduced ability to repair themselves and poor tolerance for surgery, which increases the risk of surgical treatment. Patients with osteoporotic fractures whose general condition is relatively stable and can tolerate surgery should be operated as early as possible, and the complications and mortality rate are relatively less if the surgery is performed within 24 to 72 h after the fracture. The treatment of osteoporotic fractures is based on the principles of simplicity, safety and effectiveness, and the treatment method with less surgical trauma and less impact on joint function should be chosen for the purpose of early restoration of patients’ quality of life.
1.1 Hip fracture
Hip fracture is one of the most common and serious complications caused by OP in the elderly, and mostly requires surgical treatment. Osteoporotic fractures of the hip mainly include intertrochanteric fractures and femoral neck fractures, of which the incidence of intertrochanteric fractures is slightly higher than that of femoral neck fractures. Inter-rotor fractures are less likely to have non-union and femoral head necrosis because of the rich blood flow. However, because of its poor stability, it often fails internal fixation due to bone compression, resulting in limb shortening, hip inversion and external rotation deformity. In contrast, femoral neck fractures have a higher probability of femoral head necrosis and fracture non-union due to their anatomical reasons, which is about 20% to 40%.
1.1.1 Femoral intertrochanteric fracture
Currently, osteoporotic intertrochanteric fractures should be treated surgically as early as possible and with early partial or complete weight-bearing activities if conditions permit. The choice of surgical methods mainly includes incisional internal fixation and artificial arthroplasty, among which the internal fixation methods are mainly extramedullary and intramedullary fixation. The most representative nail plate system for extramedullary fixation is the dynamic hip screw (DHS), and the proximal femoral nail (PFN) includes Gamma nail and proximal femoral nail, etc. The surgical method should be selected according to the patient’s age and fracture type.
A large number of clinical observations have confirmed that DHS internal fixation is an effective method for treating intertrochanteric fractures, which is easy to perform, has anti-rotation and sliding compression effects, and is generally weight-bearing 2 weeks after surgery. At the same time, the disadvantages of this procedure are the extensive exposure required for the placement of the plate, the greater trauma, and the longer postoperative hospital stay, especially for fractures involving the greater trochanter and severe comminuted subtrochanteric fractures, etc. The Gamma nail is nearly minimally invasive and combines the advantages of DHS and intramedullary fixation with a shorter weight-bearing arm.
Adams et al [Adams, 2001] treated 400 intertrochanteric femoral fractures with both Gamma nailing and DHS, with no significant difference in outcomes. They concluded that Gamma nailing has the advantages of small surgical incision, less trauma, and early weight bearing, but the incidence of intraoperative and postoperative complications of femoral stem fractures is higher than that of DHS.
Moroni et al [Moroni , 2005] used hydroxyapatite-coated Gamma nail to treat intertrochanteric fractures and found that patients had significantly less pain at 5 d postoperatively than the DHS group, and the fixation was more The repositioning was maintained for a longer period of time. The hydroxyapatite-coated screws also significantly reduced the rate of internal fixation failure in osteoporotic intertrochanteric fractures compared with normal screws [Moroni, 2004].The proximal anti-rotation screws of PFN were indeed effective in preventing persistent rotational instability of the fracture end and minimized the stress concentration at the nail tail, reducing the incidence of femoral stem fractures compared with Gamma nails.
Compared to DHS, PFN internal fixation allows patients to return to ambulation earlier after surgery and is indicated for inter-rotor stable fractures, anterior inter-rotor fractures and subrotor fractures [Pajarinen, 2005]. Meanwhile, Schippper et al [Schipper, 2004] concluded that DHS is more advantageous in the treatment of stable intertrochanteric fractures, while intramedullary fixation should be used to treat unstable intertrochanteric fractures as much as possible.
For elderly OP patients, it is difficult to achieve a secure fixation of the comminuted intertrochanteric fracture by internal fixation, and artificial hip replacement can be considered. As for whether to choose artificial femoral head replacement or total hip replacement (THR), it is mainly based on whether there is deformation and destruction of the acetabulum. If the acetabulum is basically intact, artificial femoral head replacement is recommended, which can save the operation time and reduce bleeding, and can basically meet the needs of daily life for elderly patients with less postoperative activities. Those aged between 65 and 75 years, in good health and with an expected survival of more than 10 years are suitable for THR treatment.
Non-cemented prostheses are also appropriate in cases with relatively young age and good bone quality. Overall, the incidence of post-THR complications is low and the duration of bed-rest treatment is short, reducing the level of pain and improving the quality of life of patients [Ren Zhang, 2003]. However, due to the severe osteoporosis of the patient, care should be taken to avoid complications such as fracture and femoral stem penetration during and after surgery.
1.1.2 Femoral neck fracture
In recent years, prosthetic replacement has become the preferred treatment for osteoporotic femoral neck fractures, and Tidermark et al [Tidermark, 2003] randomly divided 102 elderly patients (mean age 80 years) with osteoporotic femoral neck fractures into compression screw internal fixation group and THR group, and the results of postoperative follow-up at 4, 12, and 24 months showed that The incidence of complications was 36% and 4% in the internal fixation group and THR group at 24 months postoperatively, and the need for reoperation was 42% and 4%, respectively. The hip pain in the THR group was significantly lower than that in the internal fixation group, and the hip movement and walking function were significantly better than those in the internal fixation group.
A study reported that a group of patients with Garden III and IV femoral neck fractures with a mean age of 80 years were randomized to hollow nail internal fixation and THR treatment, and the results of the 4-year postoperative follow-up showed that the THR group was significantly better than the hollow nail internal fixation group in terms of hip function and quality of life [Blomfeldt, 2005].Rogmark et al. also advocated that for displaced femoral neck fractures THR is the preferred treatment for displaced femoral neck fractures in elderly patients. Weise et al. [Weise, 2003] concluded that in most elderly osteoporotic femoral neck fractures, cemented fixation provides an immediate stable joint that allows for rapid postoperative mobility and weight bearing. The incidence of prosthesis loosening and subsidence can be reduced.
According to a survey, 89% of physicians prefer internal fixation for femoral neck fractures in patients younger than 60 years of age; 25% of physicians prefer internal fixation in those aged 60 to 80 years of age, and most of them choose bipolar-head THR; 94% of physicians choose THR for femoral neck fractures in those older than 80 years of age, and 60% of them choose unipolar-head THR.
1.2 Vertebral compression fractures
Osteoporotic vertebral compression facture (OVCF) of the thoracolumbar segment is one of the most common complications of OP, and a minor trauma can cause a multi-segment vertebral compression fracture. Currently, surgery is advocated for those with vertebral body height loss greater than 1/3, or multi-segment compression fractures with severe pain. With the development of medical devices and surgical techniques, percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) have gradually become the trend in the treatment of OVCF.
Barr et al [Barr, 2000] treated 38 patients (70 vertebrae) with OVCF with PVP and injected an average of 3-5 ml of low-viscosity bone cement into each vertebra. 36 cases had complete or partial pain relief within 24 h after surgery, and only 5 cases had reoccurrence of pain at 18 months of follow-up, and none of them had re-fracture or other complications. McKiernan et al [ Mckiernan, 2005] concluded that PVP provides rapid and effective pain relief and improves quality of life in elderly and frail OVCF patients after postoperative quality follow-up.
PKP can restore the height of the vertebral body and correct the kyphosis by intraoperative high-pressure balloon expansion of the injured vertebrae, which can effectively avoid complications such as persistent thoracolumbar pain and susceptibility to fall and re-fracture after PVP. 30 patients with OVCF were treated with PKP by Lieberman et al. and the vertebral body recovered an average of 47% of the compression height after surgery. Majd et al [Majd, 2005] performed PKP surgery on 360 patients with OVCF, and postoperative follow-up found that 89% of the patients had pain relief or relief, concluding that PKP surgery is a safe and effective treatment for OVCF. Also, PKP was significantly more effective in acute OVCF (<10 weeks) than in chronic patients (>4 months) [Crandall, 2004].
Compared with PVP, PKP has the advantage of reducing the occurrence of cement leakage, restoring vertebral body height, and correcting kyphosis to some extent. Fribourg et al [Fribourg, 2004] found that the rate of secondary fractures was significantly higher in the immediate postoperative period after PKP than in the preoperative period, and most fractures occurred in the adjacent vertebrae. Grohs et al [Grohs, 2005] concluded that the analgesic effect of PKP was superior to that of PVP, but that it took about 1 year for PKP to improve disability and that the effect of correcting vertebral deformity was mainly limited to the treated vertebrae.
Meanwhile, some scholars believe that the expander often causes displacement of the original fracture cortical bone in the process of propping up the vertebral body, resulting in increased leakage of bone cement, and the expander disrupts the trabecular structure, which can lead to changes in its original mechanical properties. During the follow-up, some scholars found that the loss of vertebral body height and the increase of vertebral body kyphosis angle after PKP were more obvious than PVP, and the X-ray showed a reduction of cancellous bone in the treated vertebral body and the bone cement tightly adhered to the end plate, but no corresponding clinical symptoms were found yet.
2. Strengthening techniques for internal fixation of osteoporotic fractures
In addition to choosing a reasonable internal fixation method for osteoporotic fractures, an important issue for orthopedic surgeons is how to maintain the stability and firmness of the internal fixation to ensure that the fracture does not shift during the bone healing process and that a certain amount of functional exercise can be performed early to prevent secondary OP. In this regard, many scholars have looked to improvements in internal fixation design, intraoperative strengthening, and improved surgical technique and bone volume to improve the robustness of internal fixation in osteoporotic fractures.
Collinge et al [Collinge, 2007] found in an in vitro study of reinforced plate screw fixation with artificial osteoporotic bone blocks that tricalcium phosphate (TCP) cement and polymethylmethacrylate (PMMA) infusion of the nail tract, respectively, could Kleeman et al. used PMMA to reinforce 6.5 mm screw tracts in the distal heel and tibia of human cadavers to increase the extraction resistance by a factor of 2.3 and 1.4, respectively. Ignatius et al. used the same reinforcement technique in the spine and distal femur to achieve 1.9 and 1.2 times. The locking compress plate (LCP) can improve the stability of internal fixation for complex osteoporotic fractures.
One study confirmed that LCP can improve the stability of internal fixation by 1.5 times compared to normal plate in osteoporotic bone condition. Strengthening the nail tract with TCP can increase the stability of LCP and plain plate internal fixation by 3.3 and 3.6 times, respectively, so that strengthening LCP with TCP can increase the stability of plain plate internal fixation by 5 times overall.
Regardless of the method used to strengthen internal fixation, bone quality is the primary factor in maintaining the stability of its internal fixation. When the bone density decreases below 0.4 g/cm3, simply increasing the holding force of the screw will have no meaningful effect on the stability of internal fixation. Therefore, while increasing the stability of internal fixation, the focus should be on improving the quality of the patient’s own bone.
3. Rehabilitation of osteoporotic fractures
It is well known that limb braking can induce rapid and sustained bone loss, which is undoubtedly an aggravation to the strength and prognosis of internal fixation for existing osteoporotic fractures. Some studies have reported that the risk of re-fracture after osteoporotic fracture is significantly increased, and 20% occurs at 1 year postoperatively and 55% within 3 years postoperatively. Therefore, it is especially important to carry out effective comprehensive rehabilitation exercises along with surgical treatment of osteoporotic fractures.
3.1 Rehabilitation of hip fractures
Cognitive ability, nutritional status, pre-injury level of function, and mental status are critical to the recovery of health after osteoporotic hip fracture surgery. Some research studies have reported that sexual antagonism and functional training can be started 6 to 8 weeks after hip fracture in elderly OP patients to improve lower limb muscle strength, maintain balance and promote functional recovery. Integrated multidisciplinary rehabilitation is the current trend in postoperative fracture rehabilitation treatment, which combines the advantages of rehabilitation exercises of related departments and can help early patients to restore their pre-injury independent living ability.
Stenvall et al. conducted multidisciplinary integrated rehabilitation in elderly patients with femoral neck fractures (mean age >70 years) after surgery. Through the follow-up of 4-12 months, they found that the integrated rehabilitation significantly improved the patients’ ability to live independently in daily life and walk independently indoors after surgery compared with ordinary conventional rehabilitation methods, and reduced the probability of patients falling and re-fracturing after surgery.
3.2 Rehabilitation of spinal compression fractures
Repeated spinal compression fractures often result in kyphosis, which causes persistent low back pain, imbalance, and re-fracture due to falls. Wearing a spinal orthosis for acute spinal compression fractures can significantly reduce paravertebral muscle spasm and pain, and later strengthen muscle ligaments to prevent further compression of the vertebral body. Wearing a spinal orthosis for a long period of time can reduce kyphosis, prevent swaying of the body when walking, and prevent re-fractures caused by falls.
At the same time, lumbar back muscle exercises are particularly important for the rehabilitation of patients with spinal compression fractures, especially those with kyphosis. A study found that in postmenopausal women, 2 years of lumbar back exercise significantly reduced the incidence of OVCF in the following 10 years.
In summary, a proper preoperative status assessment should be performed in elderly osteoporotic fractures to make a reasonable choice of surgical versus conservative treatment. For patients determined to be treated surgically, a simple, safe and effective surgical method should be selected according to the specific fracture, with emphasis on improving the stability of internal fixation. Meanwhile, multidisciplinary comprehensive rehabilitation exercises after osteoporotic fracture are crucial to the prognosis and rehabilitation of the fracture. It is believed that with the continuous development of science and technology, the treatment methods for osteoporotic fractures will be more comprehensive and effective.