Effects of metaphyseal bone tumor removal with preservation of the epiphysis and knee arthroplasty

Abstract

In this study, the effects of surgical removal of malignant metaphyseal bone tumors with epiphysis preservation and knee arthroplasty were analyzed. A total of 15 patients with malignant metaphyseal bone tumors were investigated. Six of these patients underwent epiphyseal preservation surgery with preoperative physeal distraction, termed the physeal distraction (PD) group. Nine patients underwent resection of the knee joint, combined with metal prosthesis transfer, termed the knee arthroplasty (KA) group. Tumor control, limb length discrepancy, range of movement (ROM) of the knee and functional outcome of lower limb [Musculoskeletal Tumor Society (MSTS) score and the Toronto extremity salvage score (TESS)] were assessed for these two groups. All 15 patients were followed-up after the surgery. One patient in the PD group was found to have lung tumor metastasis; however, no local tumor recurrence was found. In the KA group, local tumor recurrence was found in one patient, and lung metastases were observed in two cases postoperatively. The limb length discrepancy in patients of the PD group was 2.58±0.27 cm, which was significantly less compared with that in patients in the KA group (4.01±0.13 cm; P<0.05). In addition, the lower limb knee ROM in patients in the PD group was 127.70±14.63°, which was increased compared to that in patients in the KA group (105.70±15.48°; P<0.05). The mean MSTS score was 86.67% with a mean TESS of 82.33% in patients from the PD group, which showed no significant difference compared with the respective scores for patients in the KA group (P>0.05). Therefore, epiphyseal sparing limb-saving surgeries should be considered for the treatment of malignant metaphyseal bone tumors in children, when certain indications are satisfied.

Keywords: epiphysis preservation; knee arthroplasty; limb length discrepancy; metaphyseal bone tumors; physeal distraction.

Figure 1

A patient who underwent epiphyseal preservation surgery. (A) A preoperative MRI image shows the tumor not reaching the physis. (B) An external fixator with a T-shaped piece for the epiphysis pins is attached for physeal distraction in the leg of a patient with malignant bone tumor. (C) An X-ray image shows the separation of the epiphysis from the metaphysis (white arrow). (D) An anteroposterior and lateral X-ray image shows the situation of a patient 6 months following tumor resection and reconstruction of the defect with allograft bone graft. (E) An anteroposterior and lateral X-ray image shows the situation of the same patient 2 years following tumor resection and reconstruction of the defect with allograft bone graft. MRI, magnetic resonance imaging.

Figure 2

A patient who underwent knee arthroplasty (A and B) Preoperative MRI images show the tumor having crossed the physis. (C) A lateral X-ray image shows the tumor having crossed the physis. (D) An anteroposterior X-ray image shows the situation of the patient 6 months following knee joint and tumor resection, and reconstruction of the defect with metal prosthesis. (E) A lateral X-ray image shows the situation of the same patient 6 months following knee arthroplasty. MRI, magnetic resonance imaging.

Figure 3

Functional outcome of the lower limb in the two groups. (A) The length discrepancy of the lower limb with the tumor, which was resected, and the other healthy lower limb in patients of the PD group was significantly smaller compared with that in patients in the KA group (^*P<0.05 versus the KA group). (B) The knee ROM of lower limbs with tumor resection in patients from the PD group was significantly increased, compared with that in patients in the KA group (^*P<0.05 versus KA group). (C and D) There was no significant difference between the PD and KA groups in MSTS score or TESS results. PD physeal distraction group; KA, knee arthroplasty group; ROM, range of motion; MSTS, Musculoskeletal Tumor Society; TESS, Toronto extremity salvage score.