Abstract
The number of osteoporotic fractures is still increasing and the overall management of these multimorbid patients is demanding. Surgical management of these fractures is challenging due to often comminuted fractures and poor purchase of implants. New implants and some with add-on possibilities such as standardized cement augmentation have been developed to address these problems. With these technical innovations the overall patient outcome can be improved. This review describes general considerations in operative treatment of osteoporotic fractures and gives recommendations for a selection of frequent fracture types.
Introduction
Fragility fractures are common in the elderly and affecting up to 9 million people worldwide each year . Over the next decades there is an expected increase of these fractures . An imbalance of osteoclast and osteoblast activity leads to an overall bone mineral loss particularly in the metaphyseal regions with high proportion of cancellous bone such as the distal radius, proximal femur, proximal humerus or the spine are affected. In the elderly, associated morbidities are causing significant complication rates and a high mortality. The one-year mortality of hip fractures is up to 30% and the overall costs of medical treatment related to an osteoporotic fracture is $18 billion yearly .
From an orthopedic perspective osteoporosis often leads to fracture fixation failures. It is widely known for a long time that the holding power of the screw is decreasing with shrinking bone mass and this is especially true for nonlocking screws. Therefore, cut-out of screws and implant migration are common in osteoporotic bone. The other issue of concern is severe fracture comminution which hampers fracture fixation. Bone regeneration may be handicapped in the elderly due to age- related changes but interestingly there is no evidence that an osteoporosis therapy alters fracture healing and mostly an inappropriate fixation facilitates loss of reduction and malunion.
General considerations on osteoporotic fracture fixations
Plates and locked plates
Plates are classified as load bearing devices in order to achieve fracture stability through the friction forces between the plate and bone . There are several principles to bear in mind when plating an osteoporotic fracture. Firstly a gap in the fracture zone should be avoided especially so in a comminuted situation. In the presence of a fracture gap, the entire load is carried by the implant without bone contact and this is likely to cause implant failure. The best way to avoid this is to achieve cortical contact at the fracture site which sometimes requires shortening. But as shortening of the bone alters anatomy and leads to malunion this should only be done in exceptional cases. Second, screw positioning is essential in order to achieve a felicitous construct. The working length of a plate is the distance between the closest screws on both fracture sites and is important to define tortional and axial stiffness. This distance should be as short as possible by positioning these screws very near to the fracture site. As showed by Sanders and coworkers , longer plates significantly improve the bending strength. These findings suggest that an ideal construct maximizes plate length and minimizes working length . An advantage over the last decade is the locked plate which shifts the stability from bone/plate-friction to the screw/plate interface . This angular stability prevents screws from toggling within the plate and requires a breakdown of the whole construct in case of a failure. The main benefits of these locked plates is fixation in the metaphyseal region . Interestingly the incidence of peri-implant fractures after locked plating is as high as 2.6% due to the stress-riser resulting from the mismatch of high stiffness of the plate/screw construct and low stiffness of the osteoporotic bone. Using a non-locked screw at the plate end instead of a locking screw has shown to improve bending strength without reduction of torsional loads . Same rigidity reduces micromotions at the fracture site which – especially in periarticular comminuted fractures – would be needed for secondary fracture healing and this fact leads to a nonunion rate of up to 19% . Another problem of locked plating is the inability to use the plate-screw construct for reduction. This can be addressed with combi-holes in the plate which have both locking and non-locking option allowing for equivalent bending strength compared to the use of locking screws alone . Biomechanical findings shows that in osteoporotic bone at least three bicortical screws should be used on each side of the fracture line in order to optimize torsional stiffness .
Intramedullary nails
These devices are the gold standard in the treatment of diaphyseal fractures in the lower extremities. The load is equally distributed within the fixation construct in comparison to the excentric loading of plate fixations. One main advantage is the preservation of blood supply, fracture hematoma and soft tissues in the fracture zone which facilitates fracture healing . In osteoporotic fracture treatment with intramedullary nails there are two major issues – first the nail diameter and second the interlocking screws. A larger nail diameter has to be inserted to maximize the stability within the medullary canal which is known to be enlarged in osteoporosis . The weak points of intramedullary nails especialy in osteoporotic bones are the interlocking screws in the metaphyseal region. As they are principally needed to achieve rotational and axial stability in weak bone they are likely to fail . Several attempts were taken to enhance fixation such a interlocking in multiple planes, cement augmentation or the use of a washer . Newer developments include the use of blades instead of screws which have a greater load bearing surface and therefore higher stability or the use of angle stable locking screws . The latter are special designed screws which are fixed within the nail by usage of a biodegradable sleeve with inside thread and biomechanical studies showed that they provide significantly higher stability compared to usual interlocking screws .
Augmentation
Main problem in construction failures in osteoporotic bone are affecting the metaphyseal region or the head-neck fragment – thus cancellous bone. Osteoporosis results in reduced bone mass and these effects in the cancellous bone leads to a smaller bone/implant contact area and therefore decreases the holding power for implants. With bone augments such a polymethylmethacrylate (PMMA) or tricalcium phosphate bone cement, the contact area can be increased and the anchorage of the implant in cancellous bone made stronger . One problem is that the PMMA cement does not integrate into the bone structure and becomes permanent and is probably hard to remove if needed. With tricalcium phosphate this is not the case as it works as a scaffold for the bone progenitor cells and is remodeled into native bone with time. Another issue of the PMMA is heat development while the cement is hardening which may be harmful for the surrounding tissue . The maximum heat is depending on the amount of applied cement and recent studies showed hardening within a hazard-free range of temperature for a special PMMA cement used for standardized augmentation technique for hip fractures . The standardized use of such bone substitutes is widely known in spine surgery for screw fixation within the osteoporotic vertebral body and newer developments include other body regions such as the hip or the proximal humerus .
General considerations on osteoporotic fracture fixations
Plates and locked plates
Plates are classified as load bearing devices in order to achieve fracture stability through the friction forces between the plate and bone . There are several principles to bear in mind when plating an osteoporotic fracture. Firstly a gap in the fracture zone should be avoided especially so in a comminuted situation. In the presence of a fracture gap, the entire load is carried by the implant without bone contact and this is likely to cause implant failure. The best way to avoid this is to achieve cortical contact at the fracture site which sometimes requires shortening. But as shortening of the bone alters anatomy and leads to malunion this should only be done in exceptional cases. Second, screw positioning is essential in order to achieve a felicitous construct. The working length of a plate is the distance between the closest screws on both fracture sites and is important to define tortional and axial stiffness. This distance should be as short as possible by positioning these screws very near to the fracture site. As showed by Sanders and coworkers , longer plates significantly improve the bending strength. These findings suggest that an ideal construct maximizes plate length and minimizes working length . An advantage over the last decade is the locked plate which shifts the stability from bone/plate-friction to the screw/plate interface . This angular stability prevents screws from toggling within the plate and requires a breakdown of the whole construct in case of a failure. The main benefits of these locked plates is fixation in the metaphyseal region . Interestingly the incidence of peri-implant fractures after locked plating is as high as 2.6% due to the stress-riser resulting from the mismatch of high stiffness of the plate/screw construct and low stiffness of the osteoporotic bone. Using a non-locked screw at the plate end instead of a locking screw has shown to improve bending strength without reduction of torsional loads . Same rigidity reduces micromotions at the fracture site which – especially in periarticular comminuted fractures – would be needed for secondary fracture healing and this fact leads to a nonunion rate of up to 19% . Another problem of locked plating is the inability to use the plate-screw construct for reduction. This can be addressed with combi-holes in the plate which have both locking and non-locking option allowing for equivalent bending strength compared to the use of locking screws alone . Biomechanical findings shows that in osteoporotic bone at least three bicortical screws should be used on each side of the fracture line in order to optimize torsional stiffness .
Intramedullary nails
These devices are the gold standard in the treatment of diaphyseal fractures in the lower extremities. The load is equally distributed within the fixation construct in comparison to the excentric loading of plate fixations. One main advantage is the preservation of blood supply, fracture hematoma and soft tissues in the fracture zone which facilitates fracture healing . In osteoporotic fracture treatment with intramedullary nails there are two major issues – first the nail diameter and second the interlocking screws. A larger nail diameter has to be inserted to maximize the stability within the medullary canal which is known to be enlarged in osteoporosis . The weak points of intramedullary nails especialy in osteoporotic bones are the interlocking screws in the metaphyseal region. As they are principally needed to achieve rotational and axial stability in weak bone they are likely to fail . Several attempts were taken to enhance fixation such a interlocking in multiple planes, cement augmentation or the use of a washer . Newer developments include the use of blades instead of screws which have a greater load bearing surface and therefore higher stability or the use of angle stable locking screws . The latter are special designed screws which are fixed within the nail by usage of a biodegradable sleeve with inside thread and biomechanical studies showed that they provide significantly higher stability compared to usual interlocking screws .
Augmentation
Main problem in construction failures in osteoporotic bone are affecting the metaphyseal region or the head-neck fragment – thus cancellous bone. Osteoporosis results in reduced bone mass and these effects in the cancellous bone leads to a smaller bone/implant contact area and therefore decreases the holding power for implants. With bone augments such a polymethylmethacrylate (PMMA) or tricalcium phosphate bone cement, the contact area can be increased and the anchorage of the implant in cancellous bone made stronger . One problem is that the PMMA cement does not integrate into the bone structure and becomes permanent and is probably hard to remove if needed. With tricalcium phosphate this is not the case as it works as a scaffold for the bone progenitor cells and is remodeled into native bone with time. Another issue of the PMMA is heat development while the cement is hardening which may be harmful for the surrounding tissue . The maximum heat is depending on the amount of applied cement and recent studies showed hardening within a hazard-free range of temperature for a special PMMA cement used for standardized augmentation technique for hip fractures . The standardized use of such bone substitutes is widely known in spine surgery for screw fixation within the osteoporotic vertebral body and newer developments include other body regions such as the hip or the proximal humerus .
Special considerations
Proximal humerus
Proximal humerus fractures are very common fragility fractures with a yearly increasing incidence of 298/100,000 persons per year in the octogenarian . Only about 15% of these fractures are treated operatively as they are displaced and unstable. Noteworthy a recent randomized controlled study have shown no difference in the one year outcome of three-part and four-part fractures treated either operatively or conservatively . Overall the indication for operative treatment is now more focused on the patients characteristics and moves away from strict radiological classifications .
Fracture fixation may be challenging at the proximal humerus particularly due to the presence of osteoporosis of the humeral head which was formerly compared to an eggshell. Another specific problem of the humerus head is its blood supply. The main perfusion comes from the posterior circumflex artery and this vessel is known to be damaged in 80% of the cases. A neovascularization is thought to occur and with a proper surgical technique, the overall head necrosis rate is 2.3–3.1% .
Nonoperative treatment
This includes the immobilization with a shoulder-arm sling or a Velpeau bandage and should be combined with early gentle movements starting not later than after two weeks . Later on when the patient has less pain the range of motion can be increased. Major complications are non-union, secondary displacement and humeral head necrosis .
Surgical treatment
Closed reduction and percutaneous pinning
This technique may be used for certain fracture types without massive displacement and no involvement of the area below the surgical neck. The technique requires additional immobilization of the shoulder joint in order to prevent a loss of reduction. Keener et al. showed good functional and healing results in a population with a mean age of 61 years . In the geriatric population the overall goal is to restore the prefractural function as soon as possible. This requires surgical techniques which allow an early full weight bearing as tolerated. Furthermore the holding power of single pins in the osteoporotic humeral head is reduced.
Intramedullary devices
Intramedullary nailing of humeral head fractures is a newer development ( Figs. 1–4 ) and was described to be an alternative to plate fixation within a mixed age population. Main concerns were the iatrogenic damage to the rotator cuff at the entry point of the nail which lead to development of nails having the entry point at the superior cartilage . Anatomical repair of the rotator cuff is mandatory to decrease postoperative shoulder pain. Although fixation was described for three-part and four-part fractures, the ideal indications are simple two-part fractures .
Plate fixation
With the development of locking screws, a new era begun in plating of proximal humerus fractures in osteoporotic bone. In addition special anatomical plate designs with additional options to suture the rotator cuff in order to increase stability was developed . Some aspects have to be pointed out as crucial in this context. First, a medial support at the calcar region and an anatomical reduction has been identified to be most necessary in order to prevent a fixation failure . Second, the plate must not be placed to high causing impingement with abduction. Furthermore the screw length has to be checked carefully with image intensifier in order to avoid screw penetration to the shoulder joint damaging the glenoid cartilage. This is especially necessary as best purchase of the screws is expected to be at the subchondral region . An additional augmentation of the screws with a PMMA ( Figs. 5 and 6 ) cement leads to a higher stability of the construct in biomechanical settings but clinical studies have not proven it yet. Another augmentation option is the use of a fibular strut graft for medial support of displaced proximal humerus fractures. Neviaser et al. showed good clinical results with this technique in a mixed age population .
Arthroplasty
With the development of site specific locked plates the formerly widely recommended primary shoulder arthroplasty for treatment of three-part and four-part fractures have been reduced . The hemiarthroplasty as a primary treatment showed lower functional outcome rates than expected . Healing of the tubercula in an anatomical position has a high impact on the functional outcome . A total shoulder arthroplasty may be indicated if the head is not salvageable while the rotator cuff is intact . In the elderly the rotator cuff is known to have preexisting tears in a number of cases and in these cases a reversed hemiarthroplasty may lead to good functional results .
Conclusion
Due to the high impact of poor bone quality in proximal humerus fractures, percutaneous pinning after closed reduction is not very often used. Locked plating seems to be the standard for displaces fractures whereas the use of intramedullary nails is increasing. Hemiarthroplasty and reversed arthroplasties have shown good functional results if done in a proper way and are still mostly salvage procedures. Finally it has to be mentioned that conservative treatment is done in most of the cases.
Distal radius fractures
Distal radial fractures are the second most common osteoporotic fractures . Generally, the treatment of distal radial fractures has been well documented in the literature. Factors for decision making include stability of the fracture, intraarticular involvement and joint congruency . Most of the literature dealing with distal radius fractures is based on findings in younger patients. When geriatric distal radial fractures are considered, the clear indications for operative treatment become more controversial and sometimes even contradictory. In elderly patients, fracture reduction, and anatomical alignment do not correlate with functional outcomes . Notwithstanding, there have been some studies reporting that locking plate fixation of elderly patients can achieve good outcomes . Whereas external fixators are also available to manage distal radial fractures with good functional outcomes, in elderly patients volar locking plate fixation has become the standard in the operative treatment of these fractures.
In the geriatric population there are patients with the typical pattern of the low demanding geriatric patient coming along with a high perioperative risk due to multiple comorbidities. On the other hand many of the elderly remain highly active doing sports or at least being self-supporter. These considerations have to be taken into account in order to decide about the proper treatment for the individual patient. Another necessary part in decision making is the presence of intraarticular involvement, significant shortening, or metaphyseal comminution which affects the stability of fracture reduction, and hence, the success rate of maintaining the reduction by non-operative means.
Nonsurgical treatment
Most distal radial fractures can be treated non-operatively using closed reduction and cast immobilization. Generally, the fracture is considered stable when the fracture alignment is maintained with minor displacement after a period of cast immobilization for 4–6 weeks. Risk factors for the displacement include: age, initial displacement, ulna fracture, and intraarticular involvement. This is a rather general statement that applies to all age groups. In the geriatric group, it is not entirely true clinically because the radiological outcome does not correlate with the functional outcome . However, it is important to note that displacement, especially shortening >6 mm can affect function in active elderly patients .
In low-functioning, low-demand patients living sedentary lifestyles, non-operative treatment is good, provided that cast consequences, namely atrophy and stiffness, can be avoided by early mobilization of the fingers and thumb .
Surgical treatment
Open reduction and internal fixation using the locking plate system and the volar approach has become increasingly popular with excellent results in elderly patients . When compared with other methods like the external fixator, open reduction and internal fixation has also been shown to be superior in outcomes and complication rate .
The rate of recovery and limitations of Activities of daily Living – ADL during treatment affects the quality of life of the geriatric patient with a distal radial fracture. Compared to younger patients, the geriatric group already experiences a delay of six months in gaining functional improvement. These findings imply that the rate of recovery of ADL performance and the possibility of major complications during recovery may be more important than the final functional outcome when deciding on a treatment method .
The volar approach is the most common for elderly patients, for both intra- and extraarticular fractures.
Most fixed fractures can be mobilized immediately. The most important thing is to instruct the patients to exercise the fingers and thumb immediately. Gentle, early mobilization is the key to success.
Conclusion
There is no consensus on the best treatment for the distal radial fracture in elderly patients because there is insufficient evidence as to whether operative or non-operative treatment is better with regards to long-term functional outcome . Indications for surgical treatment are judged individually based on the balance of risks and benefits. Since there is no great difference in long-term functional outcome (ie, quality of life after the injury), the speed of recovery, the control of pain, the limitations of activities of daily living, and the complications are the points for consideration. Quality of life is a measure of lifestyle, activities, and attitude, but not age. Therefore, the treatment which is most appropriate may be the result of a combination of physiological age and sometimes even geographical factors .
Hip fractures
These are the most common osteoporotic fractures and associated with high morbidity and mortality rates. 90% of all hip fractures are caused by a low energy trauma such as a fall from standing height . The increase of the number on elderly persons will also result in an increase of hip fractures. Up to half a million hip fractures are expected for the U.S. by 2040 . Mortality in the first year is up to 30% and disability rates and dependency are also very high . In the elderly patients with multiple comorbidities poor functional outcome rates are still common . Nevertheless upcoming developments with ortho-geriatric comanagement can lead to better outcome rates and lower complication rates . The main treatment goal is to restore the prefracture functional level which also includes a weight bearing solution for fracture fixation.
Treatment
Femoral neck fractures
This is the group of intracapsular hip fractures and classified into four groups as described by Garden. The degree of dislocation is associated with femoral head necrosis rate due to an interruption of perfusion.
Stable intracapsular fractures with impacted or non-displaced pattern can be addressed with cannulated screw fixation in a percutaneous manner whereas there is an incidence of nonunion from 2% to 15% . The osteosynthesis of intracapsular fractures in the elderly is – depending on the initial dislocation – associated with high rates of collapse necessitating a reoperation commonly with arthroplasty or femoral neck shortening and subsequent gait disorders . For displaced femoral neck fractures an arthrolasty is the choice of treatment. This allows immediate full weight bearing and there is no risk of head necrosis. Gjertsen compared internal fixation with bipolar prosthesis for these types of fracture in the elderly and found advantages such as improved postoperative function, reduced reoperation rate and higher patient satisfaction with the bipolar prosthestis . Hemiarthroplasty has a lower risk of dislocation and is less invasive. A total hip arthroplasty is used in relatively younger patients and in patients with preexisting signs of arthritis .
Pertrochanteric fractures
For extracapsular hip fractures the AO classification is widely used and groups the fractures into 3 types whereby the A1-type is simple, the A2-type is multifragmentary and the A3-type is intertrochanteric or reversed. For the simple fracture types a sliding hip screw is a valid and inexpensive method for fixation. The construct allows a controlled compression of the fracture and is widely accepted. Correct reduction and proper placement of the lag screw within the head-neck fragment is the key for optimal results as the failure risk of approximately 10% is mostly due to an improper screw placement . From a biomechanical perspective the center–center position of the lag screw results in lower rotational forces during mobilization and may therefore lead to lower cutout rates . Main limitations of the dynamic hip screw are the unstable fractures with multiple fragments, reversed fractures or subtrochanteric fracture lines resulting in higher rates of fixation failure . For these types of fracture a cephalomedullary nail is another option. Saudan described the lower blood loss, the independency from intact medial cortex, the shorter lever arm and the shorter operation time as main advantages of intramedullary nails compared to an extramedullary device such as a dynamic hip screw for fixation of unstable pertrochanteric fractures . Interestingly many randomized trials have not shown significant advantages of the intramedullary nails . However, intramedullary nails provide a stable fixation for reversed intertrochanteric fractures and subtrochanteric fractures and are also favored for unstable pertrochanteric fractures if the lateral wall of the greater trochanter is fractured as this is otherwise often associated with high reoperation rates . Cephalomedullary nails are available either with a screw or a blade for fixation of the head-neck fragment. The screw is most common and widely known. The blade is hammered into the head and compacts the surrounding bone which leads to higher stability . From a biomechanical perspective the blade is superior to a screw due higher cut-out resistance . Recent developments include even an option for standardized cement augmentation of the helical blade ( Fig. 7 ) which improves stability and also leads to good clinical results . Main advantage is the high stability which provides a good purchase of the implant in osteoporotic bone whereas the long-term clinical results are not known yet.
Related posts:
Hip fracture as the tracer condition
Multi-disciplinary care of the patient with acute hip fracture: How to optimise the care for the elderly, traumatised patient at and around the time of the fracture to ensure the best short-term outcome as a foundation for the best long-term outcome
Osteoporosis and fragility fractures: Vertebral fractures
Prevention of incident fractures in patients with prevalent fragility fractures: Current and future approaches
How can you prevent falls and subsequent fractures?
Secondary prevention and estimation of fracture risk
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
