Orthopedic Surgical Treatment of Patients with Tumor-induced Osteomalacia Located in the Hip Bones: A Retrospective Analysis of 10 Years in a Single Center

Abstract

Objective: The orthopedic surgical treatment strategies for patients with tumor-induced osteomalacia (TIO) require improvement, especially for patients where the causative tumors are located in surgically challenging areas, requiring a greater degree of in-depth investigation. This work aims to summarize and investigate clinical features and orthopedic surgical treatment effects of patients with tumor-induced osteomalacia (TIO), whose causative tumors are located in the hip bones.

Methods: A retrospective analysis was conducted on the clinical data of all patients diagnosed with culprit tumors located in the hip bones who underwent surgical treatment at the orthopedic bone and soft tissue tumor sub-professional group of Peking Union Medical College Hospital from January 2013 to January 2023. This retrospective study summarized the clinical data, preoperative laboratory test results, imaging findings, surgery-related data, perioperative changes in blood phosphorus levels, and postoperative follow-up data of all patients who met the inclusion criteria. Normally distributed data are presented as mean and standard deviation, while non-normally distributed data are shown as the means and 25th and 75th interquartile ranges.

Results: The clinical diagnostic criteria for TIO were met by all 16 patients, as confirmed by pathology after surgery. Among the 16 patients, we obtained varying degrees of bone pain and limited mobility (16/16), often accompanied by difficulties in sitting up, walking, and fatigue. An estimated 62.5% (10/16) of patients had significantly shorter heights during the disease stages. All 16 patients underwent surgical treatment for tumors in the hip bones, totaling 21 surgeries. In the pathogenic tumor, there were 16 cases of skeletal involvement and none of pure soft tissue involvement. Out of the 16 patients, 13 cases had a gradual increase in blood phosphorus levels following the latest orthopedic surgery, which was followed up for 12 months to 10 years. Due to unresolved conditions after the original surgery, four patients received reoperation intervention. Two cases of refractory TIO did not improve in their disease course.

Conclusion: In summary, the location of the causative tumor in the hip bone is hidden and diverse, and there is no defined orthopedic surgical intervention method for this case in clinical practice. For patients with TIO where the tumors are located in the hip bones, surgical treatment is difficult and the risk of postoperative recurrence is high. Careful identification of the tumor edge using precise preoperative positioning and qualitative diagnosis is crucial to ensure adequate boundaries for surgical resection to reduce the likelihood of disease recurrence and improve prognosis.

Keywords: Hip bone; Orthopedic surgery; Treatment strategy; Tumor‐induced osteomalacia.

FIGURE 1

Time distribution map of disease progression from onset to diagnosis for all patients included in this study.

FIGURE 2

The distribution diagram of the locations where fractures/insufficiency fractures occurred in patients included in this study during the course of the disease.

FIGURE 3

Anatomical distribution map of the hip bones where the responsible tumors were located (Created with BioRender.com, and the license to publish from the BioRender has been obtained).

FIGURE 4

Case 1 (A) The octreoscan showing the suspected culprit tumor in left acetabular region. (B) The ⁶⁸Ga‐DOTATATE PET/CT revealing high intake in the left acetabulum. (C, D) MRI of the hip revealing the mass, which was highly indicative of the causative tumor. (E, F) The postoperative X‐ray of the pelvis. (G) Serum phosphorus levels elevated to the normal range after the operation.

FIGURE 5

Case 2 (A) CT of the hip showing the suspected culprit tumor of the left acetabulum. (B) MRI of the hip revealing the suspected causative tumor. (C) The first‐line ⁶⁸Ga‐DOTATATE PET/CT scan showing high intake in the left acetabulum. (D) Postoperative X‐ray demonstrating the position of the internal fixation was satisfactory. (E) Pathological results confirmed the diagnosis of phosphaturic mesenchymal tumor. (F) Serum phosphorus levels elevated to the normal range postoperative.