Implant and limb survival after resection of primary bone tumors of the lower extremities and reconstruction with mega-prostheses fifty patients followed for a mean of forteen years.

PURPOSE: Previous studies reported variable outcome and failure rates after mega-prosthetic reconstructions in the lower extremities. The purpose of this study was to make a long-term single-center evaluation of patients treated with limb-sparing surgery and reconstruction with mega-prostheses in the lower extremities. METHODS: We identified 50 patients (osteosarcoma (n = 30), chondrosarcoma (n = 9), osteoclastoma (n = 6), Ewing sarcoma (n = 4), angiosarcoma (n = 1)), who underwent limb-sparing reconstruction of the lower extremities (proximal femur (n = 9), distal femur (n = 29), proximal tibia (n = 9), and the entire femur (n = 3)) between 1985 and 2005. Surviving patients not lost to follow-up were evaluated using the MSTS score. Causes of failure were classified according to the Henderson classification. Kaplan-Meier survival analysis was used for evaluation of patient, prosthesis, and limb survival. RESULTS: Twenty-eight patients were alive at follow-up. Fifty-four percent had revision surgery (n = 27). The ten year patient survival was 60% (95%CI 46-74%); the ten year implant survival was 24% (95%CI 9-41%), and the ten year limb survival rate was 83% (95%CI 65-96%). Type 1 failure occurred in 9%, type 2 in 16%, type 3 in 28%, type 4 in 18%, and type 5 in 3%. Mean MSTS score was 21 (range, 6-30), representing a median score of 71%. CONCLUSIONS: Our long-term results with mega-prostheses justify the use of limb-salvage surgery and prosthetic reconstruction. Our results are fully comparable with other findings, with regard to limb and prosthesis survival, but also with regard to functional outcome.

Validity and reliability of an ultrasound measurement of the free length of the Achilles tendon.

INTRODUCTION: Valid length measurements of the different segments of the Achilles tendon are needed in order to investigate if differential elongation of the Achilles tendon takes place after rupture. The purpose of this paper was to present data concerning the accuracy and reliability of an ultrasound measurement of the free part of the Achilles tendon. METHODS: Both legs of 19 non-injured subjects were examined by magnetic resonance imagining (MRI) and ultrasound. The length from the distal tip of the soleus muscle to the tendon insertion on the calcaneus was measured by three independent ultrasound examiners. Repeated ultrasound measurements were performed and compared with MRI measurements. Intra-rater and inter-rater reliability and the agreement between MRI and ultrasound were determined. Data were evaluated using the intraclass correlation coefficient (ICC), the standard error of the measurement (SEM) and the minimal detectable change (MDC). RESULTS: The measurement showed excellent intra-rater reliability (ICC = 0.94 (95% confidence interval (CI): 0.91-0.96), SEM = 5 mm and MDC = 13 mm) and inter-rater reliability (ICC = 0.96 (95% CI: 0.93-0.97), SEM = 4 mm and MDC = 11 mm). On average, ultrasound measurements exceeded the MRI measurements by 2 mm (non-significant), resulting in a measurement error of 5%. CONCLUSIONS: The ultrasound measurement of the free part of the Achilles tendon showed good reliability and accuracy. For comparison between groups of non-injured subjects, differences of > 5 mm can be detected. For repeated assessment of individual subject differences ≥ 13 mm can be detected. FUNDING: none. TRIAL REGISTRATION: Institutional Review Board of Zealand, Denmark, Ref. no: SJ-318.

Validation of a novel ultrasound measurement of achilles tendon length.

PURPOSE: A clinically applicable and accurate method for measuring Achilles tendon length is needed to investigate the influence of elongation of the Achilles tendon after acute rupture. The purpose of this study was to develop and validate an ultrasonographic (US) length measurement of the Achilles tendon-aponeurosis complex. METHODS: Both legs of 19 non-injured subjects were examined by magnetic resonance imaging (MRI) and US. The length from calcaneus to the medial head of m. Gastrocnemius was measured by three independent US examiners. Repeated US measurements were performed and compared to MRI measurements. Intra-rater and inter-rater reliability and the agreement between MRI and US were determined. Data were evaluated using the intraclass correlation coefficient (ICC), the standard error of the measurement (SEM) and the minimal detectable change (MDC). RESULTS: Intra-rater reliability of US assessment showed no significant differences between test days: ICC 0.96, SEM 4 mm and MDC 10 mm. Inter-rater reliability showed a systematic difference between US observers of 2-5 mm (p = 0.001-0.036); ICC 0.97, SEM 3 mm and MDC 9 mm. MRI measurements were on average 4 mm longer than US (p = 0.001). CONCLUSION: The novel ultrasound measurement showed good reliability and accuracy. For comparison between groups of non-injured subjects differences of more than 4 mm can be detected. For repeated assessment of individual subjects differences of more than 10 mm can be detected. The measurement needs to be further assessed in the setting of acute Achilles tendon rupture. CLINICAL RELEVANCE: This new ultrasound measurement might allow for length measurement of ruptured Achilles tendons in the acute and chronic state after rupture. LEVEL OF EVIDENCE: II.