Summary Cephalomedullary Nail (CMN) peri-implant femur fractures are a rare traumatic condition caused by mechanical stress concentration around the intramedullary nail that leads to a fracture at the distal end of the nail. The condition typically presents in elderly patients with localized pain and dysfunction near the implant site. Diagnosis is made with plain radiographs of the femur, which reveal the location and configuration of the fracture around the nail. Treatment is usually operative with distal femur ORIF if the CMN is stable, or revision CMN combined with distal femur ORIF if the nail is not stable. Distal femur ORIF is usually performed with a combination of cerclage wires and plates. Select patients may be treated with nonoperative treatment if they are not surgical candidates or the fracture is non-displaced and relatively stable. Epidemiology Incidence incidence peri-implant femur fractures around cephalomedullary nails are an emerging clinical issue with an estimated occurrence of 0.6% to 4% following surgery. prevalence an increasing recognition of these fractures has been noted due to the rising number of femoral fracture repairs using CMNs, especially among the elderly. US new cases the number of new cases per year in the United States is not precisely reported in the literature, but extrapolation from registry and cohort data suggests several thousand cases annually, given the high volume of hip fracture surgeries and the 1–2% complication rate. Demographics age these fractures are predominantly seen in patients over the age of 65 due to their higher likelihood of osteoporosis and an initial femoral fracture. sex females are more frequently affected than males, reflecting the general pattern observed in osteoporotic and low-energy fractures. Location body location femur, with a particular focus on the region surrounding the previously implanted cephalomedullary nail. physiologic location fractures commonly occur either at the tip of the implanted nail in the femur, indicating biomechanical stress concentration points. Risk factors osteoporosis advanced age comorbid conditions such as diabetes, rheumatoid arthritis, or chronic steroid use exacerbate risks. suboptimal surgical technique of CMN improper nail length improper distal locking screws improper nail diameter improper radius of curvature leading to cortical stress at the tip of the nail prior femoral fractures TKA can increase stress between implants Etiology Pathophysiology mechanism of injury (trauma) low-energy falls especially in the elderly with osteoporotic bones, can lead to peri-implant fractures after internal fixation using cephalomedullary nails. high-energy trauma in younger patients can also result in peri-implant fractures due to excessive force surpassing the structural integrity of the fixation and native bone. pathoanatomy mechanical stress concentrations around the nail tip promote microfractures, which can propagate under repetitive loading conditions. cell biology bone remodeling is disrupted, leading to an imbalance in osteoblast and osteoclast activity around the implant regions, contributing to fracture risk. microbiology infections are less common as an etiology for peri-implant fractures, but possible infective organisms include Staphylococcus aureus and coagulase-negative staphylococci. Genetics inheritance no specific inheritance pattern is directly associated with peri-implant fractures, but genetic susceptibility to osteoporosis can be inherited in autosomal dominant or recessive patterns. mutations mutations in genes such as COL1A1 may affect bone matrix formation and contribute to fracture susceptibility, though a direct link to peri-implant fractures specifically is not established. Associated conditions medical osteoporosis is a significant risk factor that weakens bone structure, increasing the likelihood of peri-implant fractures following femoral fixation with a CMN. orthopaedic previous femoral fractures and their surgical management implant positioning and the stress distribution around existing hardware, can contribute to the risk of secondary peri-implant fractures. Anatomy Osteology the femur, being the longest and strongest bone in the human body, has notable anatomic regions including the head, neck, greater and lesser trochanters, shaft, and distal condyles. The peritrochanteric region, relevant for peri-implant fractures, involves the proximal femoral anatomy surrounding the cephalomedullary nails. Arthrology the hip joint, a ball-and-socket synovial joint, is formed between the acetabulum of the pelvis and the femoral head. It provides a wide range of motion essential for weight-bearing activities. Muscles the primary muscles associated with the femur include: muscles of the hip: Responsible for movement stabilization, flexion, extension, abduction, and rotation of the hip joint. quadriceps Femoris: Extends the knee and stabilizes the patella. the muscles insert mainly onto the greater and lesser trochanter, shaft, and supracondylar regions. these muscles originate primarily from the pelvis and proximal femoral areas. Tendons iliotibial Band originates at the iliac crest. inserts into the lateral condyle of the tibia. functions to stabilize the knee laterally and assist in flexion and extension of the hip. Ligaments iliofemoral Ligament attaches from the anterior inferior iliac spine to the intertrochanteric line of the femur, providing anterior support to the hip joint. Blood Supply femoral artery femoral artery and its branches provide the main blood supply to the femur. the medial and lateral circumflex femoral arteries supply the proximal femur, critical for the head and neck region, whereas the perforating branches of the profunda femoris artery supply the shaft. Nervous System and Nerves femoral nerve is primarily responsible for innervating the anterior compartment of the thigh. the sciatic nerve branching into tibial and common peroneal nerves, innervates the posterior and lateral compartments obturator nerve supplies the medial compartment. Biomechanics the femur undergoes significant biomechanical forces, mainly in bending and torsion during daily activities, due to its long lever arm. biomechanical stresses are increased in the presence of implants such as cephalomedullary nails, as they alter load distribution and can predispose to peri-implant fractures at stress risers. Classification Basic cephalomedullary Nail (CMN) peri-implant femur fractures are classified based on their location in relation to the nail, the stability of the fracture, and the integrity of the hardware. fracture Location type 1: Fractures at the proximal end of the nail, encompassing the femoral neck and head region. type 2: Fractures occurring around the distal portion of the nail, typically in the diaphyseal region. fracture Stability stable: Fractures without significant displacement, maintaining alignment. unstable: Fractures with displacement or comminution, risking loss of alignment. Advanced in-depth classification considers biomechanical, radiographic, and surgical factors. biomechanical Component assessment of load transfer at the fracture site, considering lever arms, force distribution, and implant stress points. radiographic Classification morphological analysis using advanced imaging (CT, MRI) to visualize fracture patterns and cortical involvement. evaluation of nail protrusion or bending as indicators of potential hardware compromise. surgical Considerations surgical strategy influenced by fracture type, patient's bone quality, and presence of osteolytic lesions. decision-making for potential hardware revision or augmentation, including considerations for bone grafting or additional fixation. Presentation History basic investigate any recent trauma or fall history, especially in the context of previous femoral surgeries. determine if the patient has previously had a Cephalomedullary Nail (CMN) fixation. advanced assess for any history of osteoporosis or metabolic bone diseases. evaluate the presence of systemic conditions affecting bone health, such as rheumatoid arthritis or chronic steroid use. inquire about previous complications from the initial CMN procedure, such as infection or non-union. Symptoms common symptoms location pain localized to the thigh or hip region, often adjacent to the site of the original nail insertion. duration pain onset typically occurs immediately after a traumatic event but can be delayed in stress fractures associated with hardware fatigue. severity pain is often severe, exacerbated by weight-bearing activities, and alleviated by rest. aggravating / alleviating factors weight-bearing activities significantly aggravate the pain, while rest and immobilization may provide temporary relief. rare symptoms referred pain to the knee or lower back due to compensatory gait changes. painful hardware loosening may lead to crepitus or snapping sensations. Physical exam inspection deformity visible deformity or malalignment of the affected limb. swelling significant swelling or hematoma formation in the soft tissue around the site of fracture. palpation tenderness to palpation over the lateral thigh or proximal femur, often with crepitus. range motion flexion limited flexion due to pain or mechanical blockage. extension restricted extension often due to protective muscle spasms. rotation internal and external rotation may be severely limited by pain. vascular normal vascular examination unless there is swelling causing compression; assess distal pulses and capillary refill. neuro check for any neurological deficits, though typically not involved unless there is significant displacement. instability instability around the fracture site may be palpable, indicating hardware failure or fracture displacement. provocative tests gentle axial loading may reproduce pain, indicating fracture site stress. Imaging Radiographs required views xrays that should always be obtained on evaluation anteroposterior (AP) view of the pelvis. full-length femur AP and lateral views. optional views secondary views that might give additional information oblique views for better fracture line visualization. findings normal anatomy intact alignment with no evidence of new fracture lines. basic abnormal findings presence of fracture lines near the proximal or distal ends of the nail. displacement or angulation at the fracture site. advanced abnormal findings peri-implant lucency indicating potential implant loosening. comminution at fracture site compromising bone stability. measurements basic measurements degree of displacement advanced measurements (pelvic incidence) pelvic incidence helps assess spinopelvic relations but not directly linked to femur fractures. criteria dictating treatment basic criteria minimal displacement can often be managed non-operatively. advanced criteria significant displacement or comminution may warrant surgical intervention, either revision fixation or plating. sensitivity & specificity standard radiographs are highly sensitive for detecting fractures but may miss subtle implant loosening unless advanced views are used. CT indications complex fracture patterns or when radiographs are inconclusive. usually obtain to help with surgical planning views multiplanar reconstruction: Axial, sagittal, and coronal views. findings basic findings better delineation of fracture lines relative to the nail. advanced findings identification of occult fractures not visible on X-ray. assessment of implant position and potential loosening. sensitivity and specificity higher sensitivity and specificity compared to radiographs, particularly for subtle or complex fracture patterns. MRI indications evaluation of soft tissue damage or if CT findings are inconclusive. views axial, sagittal, and coronal sequences with fat suppression. findings basic findings soft tissue swelling, hematoma presence. advanced findings occult fractures and marrow edema around the implant. sensitivity and specificity highly sensitive for soft tissue and marrow changes but limited by metal artifacts from the nail. Ultrasound indications primarily for evaluation of soft tissue injuries or hematomas around the fracture site. preferred views longitudinal and transverse scans over the fracture site. finding basic findings detection of fluid collections or hematoma. advanced findings detailed assessment of soft tissue integrity. sensitivity/specific limited sensitivity and specificity for bone injuries, more informative for soft tissue pathologies. Bone scan indications suspected periprosthetic infection or delayed/non-union evaluation. sensitivity and specificity high sensitivity but low specificity; useful for detecting increased bone turnover. DEXA scan indications obtaining a DEXA scan does not change current surgical management 43% of surgeons would obtain after discharge from the hospital if the patient has not had a DEXA scan in last year Studies Labs serum routine laboratory tests such as complete blood count (CBC) and inflammatory markers (CRP, ESR) may be utilized to assess systemic inflammation or infection in peri-implant femur fractures. electrolyte panel to evaluate calcium and phosphate levels, which are critical for bone healing. urine urinalysis might be indicated to rule out systemic infection that could complicate the fracture healing process. surface (nasal swab, sputum) while not directly related to femur fractures, nasal swabs or sputum cultures could be important if there is suspicion of respiratory infection that might interfere with surgical recovery. Differential Surgical Site Infection presents with local erythema, swelling, warmth, pain, and sometimes drainage or systemic signs (fever, elevated inflammatory markers) deep infection is associated with nonunion and increased risk of hardware failure. Risk factors include open fractures, massive transfusion, and prolonged hospitalization. Common pathogens include Staphylococcus aureus and coliforms, with polymicrobial infections not uncommon. Diagnosis is confirmed by clinical, laboratory, and microbiological findings. management requires prompt surgical debridement, targeted antibiotics, and often hardware retention or staged revision depending on infection chronicity and stability Hardware Failure manifestations include implant breakage (commonly at the lag screw junction or distal aperture), screw cut-out, or loss of fixation. predisposing factors are poor fracture reduction (varus malalignment, fracture gaps >5 mm), use of short nails in unstable patterns, and nonunion. Mechanical failure typically occurs months after index surgery and is often secondary to delayed or nonunion salvage options include revision osteosynthesis (nail exchange, plate fixation) or conversion to arthroplasty, with the choice guided by patient factors and bone quality. Nonunion defined as failure of fracture healing by 6–9 months postoperatively, presenting with persistent pain, abnormal mobility, and radiographic evidence of incomplete healing. risk factors include inadequate reduction, poor implant positioning, infection, and patient comorbidities. Nonunion is a major contributor to hardware failure and may be associated with infection. management involves addressing underlying causes (e.g., infection control, revision fixation, bone grafting) and optimizing patient factors. Diagnosis Clinical Diagnosis patients typically present with acute pain, deformity, and inability to bear weight following new trauma or, less commonly, with insidious onset of pain in the thigh or hip region. physical examination may reveal localized swelling, tenderness, crepitus, and abnormal limb alignment. In the setting of prior cephalomedullary nailing, a high index of suspicion is warranted for peri-implant fracture, especially in elderly, osteoporotic patients or those with a history of low-energy falls. Radiographic Diagnosis standard anteroposterior and lateral radiographs of the entire femur, including the hip and knee, are essential to identify the fracture location relative to the existing implant fractures may occur at the tip of the nail, just distal to the implant, or at interlocking screw sites. Radiographs should be scrutinized for fracture pattern (transverse, oblique, comminuted), implant integrity, and evidence of previous fracture healing or hardware failure classification systems such as the AO/OTA and modified Vancouver classification are commonly used to describe these fractures and guide management advanced imaging (CT) may be considered in cases where fracture extension, comminution, or implant-bone interface is unclear on plain films prompt and accurate diagnosis is critical, as peri-implant femur fractures after cephalomedullary nailing are associated with significant morbidity and require tailored surgical management strategies. Treatment Nonoperative immobilization, protected weight bearing, +/- closed reduction indications rarely indication non-displaced or Minimally displaced fractures in non-surgical candidates techniques manual traction and manipulation under sedation or anesthesia outcomes variable outcomes depending on fracture stability post-reduction potential for secondary displacement Operative temporizing external fixation indications unstable patients not cleared for surgery closed reduction and definitive external fixation (ExFix) (+/- limited internal fixation) indications severe soft tissue damage or swelling preventing internal fixation timing performed urgently (same day or following day from admission), post clinical assessment techniques application of uniplanar or multiplanar frames incorporating limited percutaneous screws if stability requires outcomes effective temporary stabilization prepares for future definitive fixation open reduction internal fixation (ORIF) (with retention of existing nail) indications unstable fractures requiring anatomic restoration and rigidity existing IMN is stable and well positioned timing commence once patient's soft tissues allow usually done on urgent basis on same day of admission or following day during normal OR hours techniques reduction open reduction through a standard lateral approach fixation cerclage wires and lateral plate is most common construct extramedullary augment is an option, but rarely used outcomes high success rates with appropriate case selection potential complications include infection, hardware failure revision intramedullary nail fixation +/- distal femur ORIF with plates indications fracture patten and planning fixation would benefit from a change in the nail length stable long bone fractures affected by existing Cephalomedullary Nail IMN/CMN is unstable or improperly placed contraindications significant joint destruction or need for arthroplasty timing dependent on patient stabilization techniques reduction reduction may be performed opened or closed with MIPO technique fixation nail cephalomedullary nail is usually implant of choice placement of nail through current fracture site interlocking screw fixation for additional stability distal plates single lateral plate is most common construct outcomes successful outcomes hinge on proper biomechanical alignment reduced reoperation rates compared to other methods arthroplasty indications severely comminuted fractures in the presence of advanced osteoarthritic changes timing considered once other surgical options are excluded techniques hemiarthroplasty or total hip arthroplasty procedures outcomes good pain relief and functional restoration in selected cases amputation indications cases where limb functionality cannot be preserved Techniques Open Reduction Internal Fixation (with retention of existing nail) approach lateral incision with standard lateral approach to access the fracture site. lateral, anterolateral, or posterior approach based on fracture location reduction technqiue exposure of fracture, remove distal locking screw removal if necessary obtain provisional fixation with reduction clamps, stand-alone screws fixation techniques apply cerclage wires to obtain optimal reduction place lateral plate cerclage wires may be placed on or below plate depending on reduction strategy postoperative immobilization rehabilitation focusing on weight-bearing and range of motion as healing permits soft tissue dressing or hinged knee brace range of motion as tolerated usually advanced to WBAT at 5-6 weeks weight bearing dictated by surgeon preference and confidence in fixation complications non-union, infection, or hardware failure. Revision intramedullary nail fixation indications diaphyseal femur fractures or when existing implant provides sufficient stability for inclusion in fixation. approach closed entry through a minimal incision proximal to the trochanteric region. techniques introduction of a new nail alongside the previous implant, bridging the fracture. interlocking screws are placed to optimize stabilization. complications malalignment, leg length discrepancy, and potential for secondary procedures. postoperative care weight-bearing restrictions based on fracture stability and healing. regular follow-up with imaging to monitor healing. Arthroplasty indications fractures associated with severe arthritis or non-reconstructible cases. approach direct lateral or anterolateral approach to the hip joint. technique replacement of femoral head and/or acetabulum with prosthetic components. techniques - advanced use of modular implants to address severe bone loss. basic complications dislocation, infection, and prosthetic loosening. advanced complications periprosthetic fracture or aseptic loosening requiring revision surgery. Amputation approach considered for irreparable severe infections or traumatic damage. technique through-knee or transfemoral, determined by level of viability. Complications Postoperative Anemia, Blood Loss incidence occurs in approximately 20-30% of patients undergoing CMN. risk factors preoperative anemia. large intraoperative blood loss. high-energy trauma. diagnosis monitoring hemoglobin and hematocrit levels. clinical signs of pallor, fatigue, and tachycardia. treatment blood transfusion for significant anemia. iron supplementation. Surgical Site Infection (SSI) incidence occurs in 1-5% of cases. risk factors diabetes mellitus. obesity. prolonged surgery duration. diagnosis clinical examination for redness, swelling, and discharge. elevated inflammatory markers. treatment tested treatment in bold blue indications use of **antibiotic therapy** for mild infections. surgical debridement for severe infections. Nonunion incidence occurs in 5-10% of CMN procedures. risk factors poor bone quality. inadequate reduction or fixation. diagnosis failure to show radiographic healing over a prolonged period. persistent pain at the fracture site. treatment bone grafting or revision surgery. Stiffness / Loss of Motion / Arthrofibrosis / Heterotopic Ossification incidence affects approximately 3-7% of CMN cases. risk factors prolonged immobilization. severe initial injury. diagnosis reduction in range of motion via clinical examination. radiographic evaluation for heterotopic ossification. treatment physical therapy to enhance mobility. surgical intervention for severe cases. Hardware Failure incidence occurs in 1-3% of CMN procedures. risk factors inadequate fixation or technical error in placement. diagnosis loosening or breakage of hardware evident on imaging. treatment hardware removal or replacement if necessary. Posttraumatic Arthritis incidence develops in 5-10% of long-term CMN follow-ups. risk factors joint involvement in fracture. previous trauma. diagnosis persistent joint pain and stiffness. radiographic degenerative changes. treatment conservative management includes NSAIDs. surgical options such as joint arthroplasty for advanced cases. Prognosis Natural history of disease / Prognosis without treatment untreated peri-implant femur fractures typically result in progressive instability and potential migration of the hardware. without intervention, there is increased risk of nonunion or malunion due to lack of adequate stabilization. patients may experience persistent pain, increasing disability, and reduced mobilization which can lead to complications such as muscle atrophy and osteoporosis. the overall prognosis without treatment is poor, with a significant impact on the patient's quality of life and increased morbidity. Prognostic variable favorable early detection and proper classification of the fracture type lead to more effective treatment plans. presence of good bone quality can support effective stabilization and enhance healing. patient adherence to a guided physiotherapy program post-surgery assists in regaining function. advanced age associated with high physiological reserve can also be favorable due to potential comorbid condition management. negative poor bone quality predisposes to further fracture risk and complications in healing. delayed intervention can lead to worsened outcomes, including increased fracture displacement and soft tissue injury. significant comorbidities, such as diabetes or vascular disease, can impair healing and recovery. inadequate initial surgical intervention or improper implant selection can compromise stability and healing. Survival with treatment when appropriately managed, patients can expect significant recovery in function and pain reduction. successful surgical intervention leads to fracture union and allows resumption of near-normal activity levels. A comprehensive rehabilitation program post-treatment is crucial for maximizing outcomes and minimizing complications. overall prognosis with appropriate treatment is favorable, with most patients achieving satisfactory functional outcomes and quality of life improvement.