A hip bone graft is a surgical procedure where bone is harvested from the patient’s own body, most commonly from the iliac crest, the prominent top of the hip bone. This type of graft, an autograft, is used to repair or fuse bones elsewhere in the body, such as the spine. While many individuals recover without incident, some report persistent pain at the harvest site years after the surgery. This long-term discomfort can affect daily activities and quality of life.
Causes of Chronic Pain After Hip Bone Graft
One of the most frequent sources of long-term pain is injury to the small sensory nerves that cross the iliac crest. During a posterior harvest, where bone is taken from the back of the hip, the superior cluneal nerves can be stretched, trapped in scar tissue, or inadvertently cut. These nerves supply sensation to the upper part of the buttocks, and injury can result in neuropathic pain, characterized by burning, tingling, or numbness in that area, which is often worsened by sitting.
When the graft is taken from the anterior, or front part of the hip bone, other nerves are at risk. The lateral femoral cutaneous nerve, which provides sensation to the skin on the outer thigh, can be injured, leading to a condition called meralgia paresthetica. This results in pain, numbness, or a burning sensation along the side of the thigh. Similarly, the ilioinguinal nerve can be affected, causing pain in the groin and upper thigh region.
Musculoskeletal problems are another source of chronic donor site pain. The iliac crest serves as an attachment point for several large muscles of the abdomen, back, and buttocks. Harvesting bone requires detaching these muscles, and while they are reattached, the area can heal with less flexible scar tissue, causing pain with movement. This disruption can also lead to muscle weakness, subtle changes in walking gait, or a feeling of instability in the pelvis.
In some cases, the structural integrity of the pelvis itself is altered. The removal of bone can place stress on the nearby sacroiliac (SI) joint, and this added biomechanical stress can cause inflammation and dysfunction in the SI joint, resulting in low back and buttock pain. Although less common, the weakened harvest site can also be susceptible to stress fractures years later, or a defect in the bone can lead to an iatrogenic hernia, where abdominal contents bulge through the pelvic wall.
Diagnosing the Source of Long-Term Pain
A physical examination helps identify the cause of pain. A physician will palpate the iliac crest and surrounding tissues to find tender areas suggesting nerve irritation or scar tissue. The assessment also includes observing the patient’s gait, testing the range of motion of the hip and lower back, and performing muscle strength tests.
Imaging studies are often employed to gain a clearer picture. Standard X-rays are useful for evaluating the bone for non-healing, stress fractures, or issues with surgical hardware. A computed tomography (CT) scan offers a more detailed view for detecting complications like a hernia, while an MRI is preferred for visualizing soft tissues like nerves, muscles, and scar tissue.
A diagnostic nerve block is an effective tool for confirming nerve-related pain. This procedure involves injecting a local anesthetic near a suspected nerve, such as a cluneal or lateral femoral cutaneous nerve. If the injection provides temporary but significant pain relief, it strongly indicates that the targeted nerve is the source of the discomfort.
Management and Treatment Approaches
The initial approach to managing chronic hip graft pain is conservative and non-surgical. Physical therapy focuses on exercises to strengthen core and gluteal muscles, correct gait changes, and improve pelvic stability. Therapists may also use manual techniques to break down painful scar tissue, and over-the-counter NSAIDs can be recommended for inflammation. For neuropathic pain, physicians may prescribe medications like gabapentin or pregabalin.
Therapeutic injections are another conservative treatment. Corticosteroid injections can be administered to reduce localized inflammation around nerves or in the sacroiliac joint. For neuropathic pain confined to a specific area, topical treatments such as lidocaine or capsaicin patches can be effective.
When conservative measures fail to provide adequate relief, surgical intervention may be considered. If a specific nerve is identified as the problem, a neurectomy, which involves surgically removing the damaged portion of the nerve, may be performed. In other cases, surgery might focus on releasing a nerve entrapped in scar tissue or repairing a hernia that developed at the harvest site.
Prevention and Surgical Alternatives
Surgeons have developed techniques to minimize tissue disruption and the risk of donor site pain. The use of smaller incisions and more precise, minimally invasive harvesting tools can reduce damage to the surrounding muscles and nerves. Careful surgical planning, such as placing incisions to avoid major sensory nerves, also lowers the risk of long-term neuropathic pain.
Medical advances also provide alternatives that eliminate the need for an autograft. Allografts, which use bone from a deceased donor, are a common option that avoids creating a second surgical site. Synthetic bone graft substitutes are another alternative, including materials like ceramics and bone morphogenetic proteins (BMPs), which are engineered to provide a scaffold for new bone to grow.