A Guide To Minimally Invasive Fracture Management
As the practice of medicine continues to evolve, new advances are being initiated in the management of lower extremity trauma. These techniques involve a philosophical change regarding surgical approaches as well as technical innovations.
The first change constitutes a philosophical departure in technique from the classical AO principles for open reduction and internal fixation (ORIF). While traditional AO techniques emphasized obtaining absolute anatomic reduction and rigid internal fixation of fractures, this goal was sometimes complicated by a large incisional approach with significant soft tissue stripping.1,2 This process resulted in a devascularization of the osseous fragments, creating an environment that fostered soft tissue slough/breakdown, delayed union, nonunion, deformity and infection.3-5
We know that soft tissue blood supply is crucial for successful osseous consolidation. As proof, Borreli, et al., demonstrated that the proximal and distal tibial metaphysis have an excellent extraosseous blood supply.6 These extraosseous blood vessels supply the outer one-tenth to one-third of the tibial cortex and the intraosseous circulation supplies the remainder. Both are important for osseous consolidation but the extraosseous source is more compromised by traditional open techniques.
The second change is technical in nature with the emergence of locking plate technology and anatomically specific plates. In traditional fixation, what attaches the plate to the bone is the friction between the head of the screw and the plate. One must place the screw bicortically to achieve this friction. This arrangement can allow toggling of the screws in cases of delayed consolidation or premature increases in stress that result in a loss of stability. With locking screws, the head of the screw is threaded and engages the threaded hole in the plate. This arrangement eliminates toggling and enhances stability. All the screws are locked into the plate and help create an “internal-external fixator.”
Bicortical screw purchase is less important. The plate is not compressed to the bone. Therefore, the underlying blood supply is preserved. This has led to the concept of bridge plating in long bone shaft fractures. The plate is secure to the distal and proximal fracture fragments. This leaves any comminuted region unmolested and helps to preserve vascularity. The lag screw is less utilized and callus formation is acceptable.7,8
These changes create a more biologically friendly approach to fracture management. With complex periarticular fractures, one only needs to provide anatomical reconstruction of the articular surfaces. The metaphyseal and shaft fragments do not need to be anatomically aligned as long as the joint itself is properly oriented.
One can undertake articular reconstruction and the delivery of internal fixation either percutaneously or through small incisions. Cannulated screws and the image intensifier are the surgeon’s friends. The fixation only needs to be stable. It does not need to be absolutely rigid. One can utilize the arthroscope on larger joints to assist in the reduction of articular fracture fragments.9
Can One Use Percutaneous Techniques For Metatarsal Fractures?
The question arises as to which fractures one can reasonably treat with percutaneous or minimally invasive techniques. When considering metatarsal fractures, the Jones fracture is a classic example in which surgeons could employ percutaneous fixation. This fracture is essentially nondisplaced so it requires no reduction but only internal fixation.
Using an image intensifier for orientation, the surgeon can drive a guide percutaneously from the fifth metatarsal tuberosity across the fracture and down the shaft. Then deliver a cannulated, partially threaded screw of the appropriate length over the guide pin. The intramedullary screw is usually 4.5 or 5.0 mm in diameter. One can utilize a 4.0 mm screw with smaller metatarsals and a 6.5 mm screw in larger metatarsals.10 The key is to make sure the threads of the screw are beyond the fracture site. This technique preserves the periosteal blood supply, creates an internal bone graft and compresses the fracture.
Sometimes the surgeon can approach other fractures of the metatarsals less aggressively. In the past, one could apply finger traps made of wire mesh to the digit of the fractured metatarsal and gain length prior to proceeding with reduction. Transverse fractures are generally more stable when reduced than oblique or spiral fractures.
Stabilize the lesser metatarsals percutaneously, driving a K-wire through the head of the metatarsal in a proximal direction down the shaft. The newer nylon finger traps will not grip the digit. Surgeons can occasionally reduce the internal lesser metatarsals by manipulating the fracture after manually distracting the digit. Sometimes, one can place a K-wire in the distal fracture segment to aid in the manipulation of the fracture.
Another option is to introduce an instrument percutaneously that can push directly on the distal fragment for reduction. The first and fifth metatarsals, because of their locations, actually allow more freedom for the application of the percutaneous pointed reduction forceps and the ability to manipulate the fracture. Surgeons can fixate long oblique and spiral fractures with small cannulated screws. If the fracture is significantly comminuted, apply a small external fixator to reduce the fracture.
Can Percutaneous Reduction Treat Lisfranc, Cuboid And Talar Neck Fractures?
When it comes to Lisfranc fractures, surgeons routinely manage these with ORIF. However, there are potentially some injuries that could be successfully treated with percutaneous reduction and internal fixation. Remember that this technique has been recommended in the past.11,12 The fracture pattern that one may consider for this technique is the ligamentous injury that appears reduced on the initial radiographs but demonstrates some degree of subluxation when stressed. There generally is lateral angulation of the metatarsal bases rather than translation. Some of the dorsolateral ligaments of the metatarsal bases are intact and there is no dorsal subluxation.
All that is required is that one reduces the metatarsal bases with percutaneous forceps and delivers the fixation either with K-wires or screws. Use the pre-op CT scan to document the absence of dorsal subluxation. Also, one may attempt treatment of minimally subluxated Lisfranc injuries with closed reduction and percutaneous fixation. However, dorsal subluxation or fractures of the bases of the metatarsals will preclude this less invasive technique.
Considering the midfoot, it seems unlikely that one could treat a cuboid fracture with a minimally invasive technique. However, a simple two-part navicular fracture could benefit from such treatment.13 Since the navicular is constrained with strong ligamentous structures to the talus posteriorly and the cuneiforms anteriorly, a simple two-part fracture tends to separate (gap) in a medial-lateral direction. There is little tendency to shift anteriorly or posteriorly. Consequently, surgeons can reduce the fracture percutaneously with a large pointed reduction forceps and fixate with cannulated screws. One can place the screws either from the medial or lateral side depending on where the fracture line is located. Comminuted navicular fractures require ORIF.
Talar neck fractures will almost universally require ORIF.14 It is less common to observe a minimally displaced talar neck fracture with a reduced subtalar joint. For me, this represents an occult Type II fracture and may represent a chance for a limited approach.
Since most talar neck fractures usually extend into the anterior aspect of the body, it would be possible to visualize the fracture arthroscopically. The difficulty will be in actually manipulating the fracture either closed or percutaneously. However, one could pursue the reduction by using arthroscopic guidance and image intensification. Two or three lag screws could subsequently go from anterior to posterior.
Key Insights On Treating Calcaneal And Ankle Fractures
Surgeons now routinely treat calcaneal fractures with ORIF through the lateral extensile approach and stabilize them with maximum internal fixation. The deformities of the calcaneus after fracture and the reduction maneuvers are well known.15,16 However, one should give thought to returning to a less invasive approach in certain fractures, including fractures that are less significantly displaced and some tongue type fractures.
In these clinical scenarios, arthroscopic evaluation through the posterior facet of the subtalar joint and radiographic techniques can guide the reduction and internal fixation. If arthroscopic access is not possible, then one may utilize limited incisional exposure along the posterior facet and sinus tarsi laterally.
After obtaining radiographic confirmation of reduction, the surgeon would provide fixation with multiple screws/K-wires and perhaps a percutaneous plate. Advocates of external fixation for calcaneal fractures actually have approached these fractures using minimal invasive principles.17
Ankle fractures are extremely common. While traditional AO techniques are well known and effective, is there a more minimal way to reduce and fixate these fractures?18
Over the past several years, I have been attempting to address this issue. There are some fractures that surgeons can successfully reduce and fixate percutaneously. One can address a transverse fibular fracture through the lateral malleolus. One can visualize this fracture arthroscopically, provide anatomical reduction closed and fixate it percutaneously with an oblique lag screw directed from the tip of the lateral malleolus in a proximal direction. When there is a spiral fibular fracture at or slightly above the syndesmosis, the surgeon can sometimes reduce this percutaneously with a pointed reduction forceps.
Several attempts are usually necessary to achieve an anatomic reduction. One can fixate the fracture with a percutaneous 3.5 mm cortical lag screw. Deliver the screw from anterior to posterior and direct it somewhat inferiorly to make it perpendicular to the fracture.
The potential problem here is iatrogenic damage to the superficial peroneal nerve. Accordingly, one should make a small vertical incision at the tip of the lateral malleolus and create an extraosseous soft tissue tunnel in a proximal direction. Contour a one-third tubular locking plate to the lateral aspect of the fibula and slide it through the incision in a proximal direction. Place the two distal screws into the plate through the incision along the lateral malleolus. Place the proximal screws percutaneously. In reality, this will actually require just a small incision.
However, when the fibular fracture is located in the distal one-fourth to one-third, one problem surgeons may encounter is trying to get through the peroneal musculature in order to reduce the fracture and also place the proximal screw in the plate. Transverse fractures of the medial malleolus have defied a percutaneous approach because it is nearly impossible to place the reduction forceps appropriately. A change in design of the reduction forceps may be helpful. However, one can easily visualize the fractures arthroscopically.
Another problem is that many medial malleolar fractures have periosteum entrapped within the fracture site, negating the possibility of percutaneous reduction. Success has only occurred with obliquely or superiorly oriented medial malleolar fractures. In these cases, one can place a large reduction pointed forceps on the medial aspect of the medial malleolus and the anterolateral aspect of the tibia. One would then proceed with fixation via two 4.0 mm partially threaded cannulated screws guided with image intensification.
Surgeons have managed unstable ankle diastasis and most Maisonneuve fractures with arthroscopic examination of the ankle for osteochondral damage (usually medial talar dome) and percutaneous reduction. They have accomplished fixation with multiple, percutaneously placed, 4.5 mm cortical transsyndesmotic screws.
One can readily manage pediatric ankle fractures in the older child with arthroscopically assisted closed or percutaneous reduction. Use a large pointed bone reduction forceps to reduce or stabilize the fracture, and follow this with percutaneous screw fixation. This approach would be effective with Salter-Harris III medial malleolus, Tillaux and triplane fractures.
Pertinent Pearls On Treating Pilon Fractures
The injury that benefits most from a minimally invasive approach is the pilon fracture, which may be rotational or compressive in configuration.19,20 The rotational pilon fracture is really spiral or oblique fractures of the distal tibia, which may happen to enter the ankle joint. There may or may not be a fibular fracture, and it can occur at the level of the syndesmosis or higher.
One can usually reduce this fracture and provisionally stabilize it with a large point reduction forceps. It requires longitudinal traction and the appropriate rotation. Use an image intensifier to help aid the reduction and proper placement of the forceps.
Perform internal fixation percutaneously with a small vertical incision over the medial maleolus. Create an extraosseous tunnel and slide a precontoured distal tibial plate proximally. Anchor the plate with distal locking screws through the entrance incision and place the more proximal screws percutaneously. If the fibular fracture is at the level of the syndesmosis, reduce it and fixate it percutaneously or with ORIF. When there is a fibular fracture above the syndesmosis, one may provide fixation in the same matter or the surgeon may not fixate it, especially if the ankle joint has not been violated.
The surgeon would usually manage the compression type pilon fracture with a two-stage approach.21 The first intervention at the time of injury includes ORIF of the fibula and application of an ankle spanning simple monolateral or delta frame external fixator. If the soft tissue will allow, one may reduce the articular surface of the tibia and fixate it percutaneously or through a small incisional approach. Arthroscopic visualization may be helpful. Allow the soft tissue to stabilize.
In about seven to 18 days, one would perform the second stage of the procedure using either a minimally invasive technique or percutaneous plate fixation after removal of the external fixator. The surgeon can undertake any additional joint realignment at this time. Open pilon fractures will have undergone multiple debridements followed by the same staged approach after the wounds have healed. Sometimes, external fixation may be the definitive stabilization.
In regard to these emerging trends in fracture management, foot and ankle surgeons should think about old problems in a new way to minimize their surgical impact. This will require unconventional thinking and the development of new skills.
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