Patellar height influences knee function in patients with aggressive bone tumors of the proximal tibia after endoprosthetic reconstruction

Muscle strength characteristics following megaprosthetic knee reconstruction for bone sarcoma

OBJECTIVE

To assess muscle strength characteristics in patients with resection and megaprosthetic reconstruction of the knee for bone sarcoma compared to age- and sex-matched controls.

METHODS

This was a cross-sectional, case-control study. Muscle strength characteristics for knee extension and -flexion were assessed isokinetically at three different joint velocities: 60, 120 and 180°/s, and by the rate of force development (RDFmax) in knee extension. The Toronto Extremity Salvage Score (TESS) was used in patients.

RESULTS

Eighteen patients (91.6 months postop.) and 18 controls were included. Relative to controls, patients generated maximal torques of 19%, 23% and 23% in knee extension at 60, 120 and 180°/s, respectively. For knee flexion, patients generated maximal torques of 58%, 53% and 60% at 60, 120, and 180°/s, relative to the controls. RDFmax of the operated leg was 2.75 ± 2.13 N/ms, 7.16 ± 4.78 N/ms for the non-operated leg, and 7.95 ± 4.29 N/ms for the controls. The mean TESS score was 84.0.

CONCLUSION

Patients reached approximately 20% of the maximal knee extension torque. In isometric assessments, they used double the amount of time to generate one-third of the maximal force compared to the controls despite good TESS scores.

Reconstruction of the extensor mechanism augmented with reverse transferred iliotibial band after proximal tibia tumor resection and mega-prosthetic replacement

BACKGROUND

The optimal procedure for functional reconstruction of the extensor mechanism after proximal tibia mega-prosthetic replacement remains unclear.

METHODS

Since 2006, 14 consecutive patients with aggressive bone tumors in the proximal tibia who underwent mega-prosthetic replacement were prospectively treated with reconstruction of the extensor mechanism using an ipsilateral iliotibial band. The surgical procedure consisted of wrapping the reversed iliotibial band around the tibia component, firmly suturing it to the remaining patellar tendon and tibialis anterior fascia, and covering it with a muscle flap. At the last follow up, the function was assessed based on extensor lag, active flexion of the knee, and Musculoskeletal Tumor Society score. Patellar height was measured with the Insall-Salvati ratio (ISR) preoperatively, postoperatively, and at the last follow up.

RESULTS

At the last follow up, the extensor lag and active flexion in 14 patients averaged 2.5° and 86°, respectively. Musculoskeletal Tumor Society score could be obtained in nine surviving patients at the last follow up and was a mean of 20.7 points. The mean ISR preoperatively, postoperatively, and at the last follow up was 1.04, 0.75, and 0.89, respectively. The extensor lag was not associated with the ISR value at any points, while reduced active flexion significantly correlated with a low ISR at the last follow up (P = 0.015). Four patients underwent additional surgeries due to postoperative infection, but none required eventual revision or amputation.

CONCLUSION

The extensor mechanism reconstruction with the reverse transferred iliotibial band for mega-prosthetic replacement after proximal tibia resection yielded reliable outcomes with functional benefit to stabilize active knee extension.

Oesophageal carcinoma with solitary patellar metastasis: a rare case report

The incidence of tumours found in the patella, including primary and metastatic tumours, is low. Solitary metastasis of oesophageal carcinoma (OC) in the patella is even rarer. A 50-year-old man presented to our clinic because of pain and limited range of motion in the right knee for 4 hours and after a fall. On the basis of the patient’s medical history, he was diagnosed with OC 2 months previously and underwent two cycles of paclitaxel liposome combined with tiggio chemotherapy (oral tiggio, 40 mg, two times/day, with a treatment cycle of 3 weeks). A 99mTc-methylene diphosphonate bone scintigraphy scan showed increased radioactivity in the right patella. A right knee biopsy showed the presence of patellar metastasis from OC. Unfortunately, the patient denied additional treatment and was discharged for personal reasons. At the 1-month follow-up, which was conducted by a telephone survey, we learned that the patient had died of acute pulmonary embolism. X-rays and computed tomography are useful for diagnosing patellar metastases, but 99mTc-methylene diphosphonate bone scintigraphy can help physicians diagnose patellar metastasis of OC more rapidly. Biopsy with pathology is the gold standard for diagnosing patellar metastases. Additionally, timely surgical treatment prolongs the survival time of these patients.