Uneven hips, medically referred to as pelvic obliquity or pelvic tilt, occur when the pelvis is not level, causing one hip to appear higher than the other. This common condition can cause a cascade of effects throughout the spine and lower limbs. While it may sometimes indicate a significant underlying issue, uneven hips are frequently correctable. Understanding the root cause is the first step toward finding an effective solution.
Distinguishing Structural from Functional Causes
The two main categories of uneven hips are structural and functional, and the distinction between them governs the approach to correction. A structural unevenness, or anatomical leg length discrepancy (LLD), is caused by a fixed difference in the length of the bones in the lower limbs, typically the femur or tibia. This difference forces the pelvis to tilt to accommodate the shorter leg and is permanent without surgical intervention.
Functional unevenness, or compensatory LLD, occurs when bone lengths are equal, but the pelvis is tilted due to issues in the body’s soft tissues. Common causes include chronic muscular imbalances, where muscles on one side of the torso or hip become tight and pull the pelvis upward, while opposing muscles become weak. Postural habits, such as always standing with weight shifted to one leg or having pronated feet, can also create this compensatory misalignment. Functional issues are easier to address because they involve correcting muscle tension, movement patterns, and joint mechanics rather than fixed skeletal differences.
Identifying the Degree of Unevenness
Before treatment begins, a healthcare provider must accurately diagnose the type and severity of the pelvic obliquity. Diagnosis usually starts with a physical examination, where the clinician visually assesses the patient’s posture and gait while measuring specific bony landmarks. The anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS)—prominent points on the front and back of the hip bones—are checked for height differences to estimate the tilt.
To confirm a structural leg length discrepancy, imaging is required for precise measurement. A full-length X-ray or a CT scanogram is utilized to measure the exact length of the femur and tibia on both sides. This radiological measurement provides definitive evidence of an anatomical LLD, allowing the provider to determine the difference in centimeters or millimeters. Identifying the magnitude of the discrepancy is necessary to guide the decision between non-surgical management and more invasive procedures.
Non-Surgical Paths to Correction
The majority of people with uneven hips, especially those with functional causes or mild structural differences, can find correction through non-surgical methods. For functional unevenness, targeted physical therapy is the primary intervention, focusing on restoring balance to the musculature surrounding the pelvis and spine. This involves strengthening weak muscles, such as the gluteals and core stabilizers, while stretching chronically tight muscles, like the hip flexors or quadratus lumborum.
For individuals with a mild structural LLD, typically a difference less than 2 centimeters, equalization can be achieved using external aids. Shoe inserts, heel lifts, or custom orthotics are placed in the shoe of the shorter leg to effectively level the pelvis. This mechanical intervention reduces the compensatory strain on the spine and hips. These non-invasive methods manage symptoms and prevent secondary issues associated with minor bone length differences.
When Surgical Correction is Necessary
Surgical intervention is reserved for severe structural leg length discrepancy that cannot be adequately managed with shoe lifts or orthotics. A difference greater than 2 centimeters is the threshold for considering surgery, as discrepancies of this magnitude often lead to significant gait issues and chronic joint problems. The goal of surgery is to make the legs equal in length to permanently level the pelvis.
One approach, primarily used in children or adolescents who are still growing, is epiphysiodesis. This procedure involves surgically slowing or stopping the growth plate of the longer leg, allowing the shorter leg time to catch up and achieve near-equal length by skeletal maturity. For patients who have finished growing, limb lengthening procedures are utilized, which involve an osteotomy, or cutting the shorter bone. A fixation device is then used to gradually pull the bone segments apart, stimulating new bone formation to achieve the desired increase in length.