Back or Contralateral Hip Pain May Limit Meaningful Improvement After THA

For many patients undergoing total hip arthroplasty (THA), pain does not end with the procedure.

“Many total hip patients have pain in their other hip or their back,” says orthopaedic surgeon Matthew Deren, MD, Director of the Adult Reconstruction Fellowship at Cleveland Clinic. “Even after their hip pain is gone, other parts of their body may still be causing pain and functional limitations.”

Patients with pain in other areas often report worse outcomes after arthroplasty, notes Nicolas S. Piuzzi, MD, Vice Chair of Research for Orthopaedics and Rehabilitation at Cleveland Clinic.

“After surgery, pain in other joints can limit rehabilitation and recovery and reduce functional gains,” he says.

Dr. Piuzzi adds that it has been unclear how these factors affect achievement of substantial clinical benefit (SCB), the metric the Centers for Medicare & Medicaid Services (CMS) now requires hospitals to report for primary joint replacement patients.

That knowledge gap prompted a prospective study by Cleveland Clinic researchers, who analyzed patient-reported outcome measures (PROMs) from 4,412 Medicare patients who had primary unilateral THA between 2016 and 2023. Patients were grouped by preoperative pain profile:

• Contralateral hip pain (6%)
• Back pain (38%)
• Both contralateral hip and back pain (38%)
• No other pain (18%)

Dr. Piuzzi presented key findings of the study at the American Academy of Orthopaedic Surgeons (AAOS) 2026 meeting. Dr. Deren was a coauthor.

The analysis showed that 82% of patients having primary THA had preoperative pain in the contralateral hip, the back or both, and that these comorbid pain sources significantly reduced the likelihood of achieving meaningful functional improvement after surgery, even when the operative joint healed as expected.

Comorbid pain worsens outcomes

Using multivariate analyses, the research team compared each group’s odds of failing to achieve the CMS-defined SCB threshold: a 22-point improvement on the HOOS-JR (Hip disability and Osteoarthritis Outcome Score for Joint Replacement) at one year.

Relative to patients with no comorbid pain:

• Patients with back pain alone were 1.6 times more likely to fall short of the SCB threshold.
• Patients with contralateral hip pain alone had 1.7 times the odds of failing to reach SCB.
• Patients with both conditions were more than three times as likely not to achieve meaningful improvement.

Patient satisfaction, assessed with the Patient Acceptable Symptom State (PASS) tool, followed a similar pattern. Compared with patients with no comorbid pain at one year:

• Patients with back pain were 1.4 times more likely to report dissatisfaction.
• Patients with contralateral hip pain were twice as likely to report dissatisfaction.
• Patients with both pain types were 2.1 times more likely to report dissatisfaction.

Pain severity also mattered. For back pain, the odds of failing to reach SCB ranged from 1.7 for mild-to-moderate pain to 2.8 for severe pain. For contralateral hip pain, the corresponding odds ratios were 1.7 and 2.0.

“These findings challenge the idea that outcomes depend mainly on the operated joint,” says Dr. Piuzzi. “Global pain burden, not just hip pathology, is a major driver of outcomes.”

Implications for CMS performance measurement

The findings are especially relevant in light of the CMS Patient-Reported Outcome Performance Measure policy, which requires hospitals performing elective primary THA and total knee arthroplasty to collect complete preoperative and postoperative PROMs data for at least 50% of eligible patients. Payment determinations based on SCB improvement rates are scheduled to begin in 2028.

CMS risk adjustment does account for comorbid joint and back pain, the factors this study identifies as clinically important. Surgeons who do not thoroughly screen for and document these pain sources preoperatively may be at a disadvantage when those adjustments are applied.

“We need to be able to collect the data,” says Dr. Piuzzi. “Joint pain and back pain are extremely important as part of that risk-adjusted performance assessment. This matters for every physician, first, so we can counsel patients better, and second, because it is directly relevant to CMS reimbursement and quality metrics.”

Dr. Deren notes that current PROM instruments may not fully capture what surgeons accomplish. A patient with significant spinal stenosis, for example, may continue to report pain with stair climbing even after a technically successful hip replacement and resolution of hip pain. In that case, the reported limitation reflects the comorbidity, not the surgery.

Preoperative screening and whole-patient assessment

Both Drs. Piuzzi and Deren recommend making routine preoperative screening for contralateral joint and spinal pain standard practice before THA. When indicated, that screening should be paired with multidisciplinary optimization involving spine specialists, pain management and physical therapy.

“By better understanding individual groups of patients, we can identify which patients may not improve as much after hip replacement and then look for interventions that may help them improve,” Dr. Deren says. “It’s not that the surgery won’t be successful. It’s that there might be more to do to give those patients the best quality of life.”

Adds Dr. Piuzzi, “I think the study supports a shift toward whole-patient assessment. For value-based care to progress, we are going to need fair benchmarking.”