Introduction
Periprosthetic fracture is a medical condition that refers to a fracture occurring surrounding an implanted orthopedic prosthesis, commonly known as hip or knee arthroplasties. Peri-implant fractures are fractures that occur around rods, plates, or other prosthesis. It is also to be noted that non-prosthetic peri-implant fractures may be considered a separate entity. The incidence of hip fractures has now exceeded 300,000 annually, with most of the cases requiring operative treatment that involves prosthetic replacement. There has also been a notable increase in implants for bones such as the ankle, shoulder, and elbow.
What Are Periprosthetic Fractures?
Periprosthetic fractures following total hip arthroplasty (THA) represent a complication linked to the rising prevalence of arthroplasty procedures and the heightened demands in aged people. Diagnosis usually involves plain radiographs of the affected hip and the corresponding femur on the same side. Treatment approaches may vary and may be either nonoperative or operative, depending on factors like fracture location, implant stability, and the available bone stock.
The incidence of periprosthetic fractures is increasing due to an increase in the number of total joint replacements, an aging population, which has now extended beyond the knees and hips to include joints like the elbow and shoulder. Managing these fractures remains a significant hurdle for orthopedics. Despite extensive efforts to comprehend and address these cases, reports still show high failure rates and mortality rates.
What Are Periprosthetic Fractures?
Fractures occurring around plates, rods, or other prostheses are more generally termed peri-implant fractures. The indications for joint replacement have expanded remarkably over the years, encompassing both young and old patients, both of whom are at higher risk for periprosthetic fractures. Among the major complications of total joint arthroplasty are osteolysis (progressive bone destruction) and loosening. Osteolytic bone defects amplify with time, serve as stress risers, and predispose to fractures.
Computer-assisted navigation and robotic-assisted surgery can be adopted in joint replacement, necessitating the use of tracking pins placed in the femur and tibia. While periprosthetic fractures through pin sites have been reported very infrequently. As the utilization of computer-assisted techniques grows, such fractures are likely to increase as well.
How Do Periprosthetic and Peri-Implant Fractures Occur?
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Patients with periprosthetic fractures can have a history of either internal fixation or joint replacement for a previous fracture.
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Peri-implant fractures encompass both periprosthetic fractures and fractures around orthopedic fixation devices.
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The patient's recent medical history might involve a traumatic event, similar to non-periprosthetic fractures, or the gradual onset of increased pain due to a stress fracture around the implant.
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Intraoperative periprosthetic fractures can occur due to challenges in preparing for implant placement, such as difficulties during prosthesis insertion or over reaming the acetabulum before total hip prosthesis placement.
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Thigh pain during weight-bearing activities or reduced hip mobility prior to a fraction suggests a high likelihood of loosening.
How to Manage Periprosthetic and Peri-Implant Fractures?
Almost all periprosthetic fractures will require treatment. Minor fractures may just need limited weight-bearing or a cast or brace usage along with pain relief through drugs. However, most serious peri-implant fractures need surgery or implant replacement, or sometimes both, to regain lost function. Surgical treatment for these fractures follows similar principles as for other fractures. The treatment goals are as follows:
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Early Ambulation - Promoting early walking can prevent problems like lung issues, disuse osteoporosis (bone weakening due to inactivity), pressure sores, and other risks related to prolonged bed rest.
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Restoration of Axial Alignment - Restoring proper alignment of the body can help prevent uneven strain on the prosthesis, which can result in loosening prematurely.
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Limb Stabilization - Keeping the limb stable will allow for movement in the joint and help in preventing stiffness and atrophy of muscles.
What Are the Treatments Approached for Periprosthetic and Peri-Implant Fractures?
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Treatment is rarely discouraged after a periprosthetic fracture, although observation might be suitable for fractures in paralyzed limbs.
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Surgery can usually help in nursing care even in patients who are paralyzed.
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Cancer patients with widespread resistant metastases can benefit more from palliative care or pain control alone.
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Patients with unstable medical conditions have the need to achieve optimal health before undergoing surgery.
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If an ongoing infection is present, addressing it should be part of the surgical plan.
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Peri-implant fractures mostly occur in elderly patients and often require the participation of a multidisciplinary team for treatment.
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Current treatment approaches for the treatment of periprosthetic fractures highlight the prevention and utilize newer implants for better fixation.
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Modern prosthetic designs target at distributing loads more evenly to avoid stress shielding–induced bone weakening followed by fracture risk.
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Novel plate designs like the low-contact dynamic compression plate will help in reducing the stress shielding-induced bone weakening by decreasing plate contact area.
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Material advancements such as using less rigid materials like titanium for stainless steel can help in distributing loads more efficiently.
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Fixed-angle plate systems like the less invasive surgical stabilization (LISS) technique can ensure more stable fixation with minimally invasive procedures.
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Minimally invasive techniques are constantly under development to improve fracture healing and potentially increase the chances of bone reunion.
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Percutaneous reduction, using minimally invasive locking plates and cerclage wiring, possesses promising results in the treatment of unstable peri-implant fractures around total hip replacements.
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There is still a debate going on about the optimal approach for treating fractures after total knee replacement, with some studies showing an increased incidence of nonunion rates and hardware failures with locked plating techniques, while others find no significant differences in the surgical outcomes compared to retrograde intramedullary nails.
Conclusion
The most crucial aspect of treating peri-implant fractures is evaluating the patient’s condition. It is also important to examine preoperative X-rays and compare them with previous X-rays whenever possible to accurately assess the situation. The fracture should be regularly monitored using radiography and clinical examination until there is complete healing. Patients should also be monitored until they achieve full rehabilitation potential. For periprosthetic fractures, it is generally advised to assess the prosthesis every one to two years. For peri-implant fractures, monitoring should continue until the fracture has fully healed and union is established.
