Biomechanics of hamstring tendon, quadriceps tendon, and bone-patellar tendon-bone grafts for anterior cruciate ligament reconstruction: a cadaveric study.

PURPOSE: The three most commonly used autografts for anterior cruciate ligament reconstruction (ACL) are: bone-patellar tendon-bone (BTB), hamstring tendons (HT), and quadriceps tendon (QT). A cadaveric study was performed to determine if there were any differences in mechanical and structural properties under biomechanical testing. METHODS: Twenty-seven graft specimens were harvested from 9 human cadaveric legs. Mean donor age was 75.2 years (range 53-85 years). Twenty-two specimens (8 HT, 7 QT, and 7 BTB) completed cyclic preconditioning from 50 to 800 N for 200 cycles and a load to failure test at an extension rate of 1 mm/s. Structural and mechanical properties of BTB, HT, and QT grafts were compared using a one-way ANOVA and Tukey's honest significant difference. RESULTS: There was no difference in the ultimate load to failure (N) across all 3 graft types (p = 0.951). Quadriceps tendon demonstrated greater cross-sectional area (mm2) when compared to both HT and BTB (p = 0.001) and was significantly stiffer (N/mm) than HT but not BTB (p = 0.004). Stress (N/mm2) of the HT at ultimate load was greater than QT but not BTB (p = 0.036). Elastic modulus (MPa) of HT was greater than both QT and BTB (p = 0.016). CONCLUSION: There was no difference in the ultimate load to failure of BTB, HT, and QT grafts harvested from the same specimens. All 3 grafts had similar loads to failure with a significant increase in stiffness when compared to the native ACL. Furthermore, QT demonstrated more favourable structural properties compared to HT and BTB with greater cross-sectional area to both HT and BTB and greater stiffness compared to HT.

Revisability of polyetheretherketone suture anchors utilised in primary and revision Bankart repair.

BACKGROUND: Polyetheretherketone (PEEK) suture anchors are frequently used in Bankart shoulder stabilisation. This study analyzed the primary stability and revisability of PEEK anchors in-vitro in case of primary Bankart repair and revision Bankart repair after failed primary repair. METHODS: To simulate primary Bankart repair, 12 anchors (Arthrex PEEK PushLock® 3.5 mm) were implanted in 1, 3, 5, 7, 9 and 11 o'clock positions in cadaveric human glenoids and then cyclically tested. To simulate revision Bankart repair, 12 anchors were implanted in the same manner, over-drilled and 12 new anchors of the same diameter were implanted into the same bone socket as the primary anchors and then cyclically tested. The maximum failure loads (Fmax), system displacements, force at clinical failure and modes of failure were recorded. RESULTS: One primary anchor failed prematurely due to a technical problem. Three out of 12 revision anchors (25%) dislocated while setting the 25 N preload. The Fmax, the displacement and clinical failure of the remaining 9 revision anchors were non-significant when compared to the 11 primary repair anchors. The main mode of failure in the primary and revision Bankart surgery group was suture slippage. Anchor dislocations were observed four times in the primary and once in the revision repair groups. CONCLUSIONS: Revision Bankart repair using PEEK anchors of the same diameter in a pre-existing bone socket is possible but bears high risk of premature anchor failure and can jeopardize the reconstruction. PEEK suture anchor in revision Bankart surgery should be implanted in a new bone socket if possible.

Infection risk from surgeons' eyeglasses.

PURPOSE: To assess bacterial contamination of 20 eyeglasses from surgeons. METHODS: 40 samples were taken from the nose pad (n=20) and earpiece (n=20) of 20 eyeglasses from orthopaedic surgeons using a sterile swab stick soaked in sterile distilled water. Swabs were incubated and inoculated onto 3 plates: Staphylococcus/Streptococcus agar plate, Mannitol salt plate, and Chromogenic agar plate. Organisms isolated were identified. RESULTS: Of 20 eyeglasses, 19 were contaminated with Staphylococcus epidermidis (3 of them additionally grew S haemolyticus or S xylosus) and the remaining one grew S aureus . CONCLUSION: Eyeglasses are a source of surgical infection. Contamination can be caused by direct contact of the eyeglasses to the wound and indirect contact by the surgeon's fingers, splashes from saline irrigation, and through air. Therefore, disinfection should be performed for eyeglasses of surgeons. The use of surgical visor masks or filtered exhaust helmets (space suits) are alternatives.

Anterior construct location following vertebral body metastasis reconstruction through a posterolateral transpedicular approach: does it matter?

OBJECT: The posterolateral transpedicular approach (PTA) is a widely used method for the surgical treatment of vertebral body metastases. It is crucial to understand the optimal location of the anterior graft in terms of sound and durable reconstruction following PTA. The purpose of this study was to investigate whether postoperative construct stability is related to the location of anterior grafts. METHODS: The authors conducted a retrospective review of 45 cases of metastatic spine disease with epidural tumor extension in which patients underwent circumferential decompression and fusion by means of PTA. Mechanical (anterior construct stability), pain (visual analog scale score), and neurological (American Spinal Injury Association scale) outcomes were evaluated and correlated with the anterior graft location (lateral or central) and surgical approach (unilateral or bilateral), number of decompressed levels, types of anterior graft, screw density of posterior fixation (number of screws used divided by the number of pedicles spanned), and kyphotic angle change from the immediate postoperative period to the most recent follow-up. RESULTS: Seven of 45 constructs were judged unstable--5 with a lateral location of the anterior graft and 2 with a central location. The anterior graft was located laterally in 31 cases (69%), centrally in 11 (24%), and bilaterally in 3 (7%). A unilateral approach was used in 33 cases and a bilateral approach in 12. Neither the location of the anterior graft nor the approach had a significant effect on the stability of the reconstructed spine (p > 0.05). There was a significant difference in construct stability between the single-level decompression group (33 patients) and the multiple-level decompression group (12 patients) (p = 0.0001). The types of anterior graft, screw density, and kyphotic angle change were not correlated to the mechanical outcome. CONCLUSIONS: The anterior graft location showed no significant relationship to the final mechanical, pain, and neurological outcomes.

The treatment outcome depending on the extent of resection in skull base and spinal chordomas.

PURPOSE: The authors tried to assess the treatment outcomes depending on the extent of resection in axial chordomas and compare the outcome of two adjunctive therapies (external beam radiation therapy vs. stereotactic radiosurgery) following incomplete tumour resection in terms of local tumour control. PATIENTS AND METHODS: We retrospectively reviewed 30 consecutive patients with chordoma involving skull base, sacrum and mobile spine between 1993 and 2008. Their initial treatments had different extent of resection. Wide resection was performed for 12 (40%), subtotal resection and adjunctive radiotherapy/radiosurgery for 12 (40%), while six patients (20%) were solely treated with radiotherapy/radiosurgery. For these three groups, overall and progression-free survival rate were compared. RESULTS: The overall survival rate was 96% at 5 years and 67% at 10 years. Tumour progression-free survival (PFS) rates were 73% and 43% at 5 and 10 years, respectively. Local tumour progression was seen in 67% in all patients, 58% in wide resection group, 67% in subtotal resection plus radiotherapy/radiosurgery group, and 75% in radiotherapy/radiosurgery group; however, this was not statistically significant (P = 0.69). Neither the extent of resection nor tumour location significantly influenced overall and progression-free survival (P > 0.05). With regard to the type of radiotherapy, tumour progression occurred in all lesions treated with external photon beam radiation therapy (EBRT) but only 38% of lesions treated with stereotactic radiosurgery (SRS) (P = 0.003). CONCLUSIONS: Adjunctive radiotherapy/radiosurgery following subtotal resection showed comparable local control and survival to wide resection. SRS offered superior local tumour control compared to EBRT.

Pasteurized autograft-prosthesis composite for proximal femoral reconstruction: an alternative to allograft composite.

BACKGROUND: Allograft-prosthesis composite (APC) for proximal femur reconstruction have shown favorable longevity and functional outcome compared to endoprosthesis, owing to restoration of bone stock, load-sharing property, and biological attachment of abductors and iliopsoas tendons. QUESTIONS/PURPOSES: This study examined whether a pasteurized-prosthesis composite (PPC) is comparable to APC regarding implant survival, functional outcome, and complication rates. PATIENTS AND METHODS: We retrospectively reviewed 18 patients with proximal femur malignancy that underwent reconstruction with a cemented pasteurized autograft-prosthesis composite between 1993 and 2008. We evaluated implant survival (Kaplan-Meier), functional outcome (MSTS score), complications and secondary operations. RESULTS: The estimated survival rate of the 18 composites was 86% at 5 and 10 years. Within a mean follow-up of 93 months (median 113, range 14-163) two composites (11%) were removed due to un-resolving infection. The mean MSTS functional score of surviving 16 composites was 80% (range 70-95). Non-union and stem loosening in host bone were identified in a single patient, while infection developed in two patients. THA conversion occurred in three composites due to secondary osteoarthritis in two, and subluxation in one case. Two of the six cases, with greater trochanter (GT) reconstruction, showed GT avulsion. No autograft was fractured. CONCLUSIONS: Pasteurized autograft-prosthesis composite (PPC) of the proximal femur has comparable survival rate, functional outcome, and complication rates to allograft-prosthesis composite (APC), thereby offering an alternative reconstructive option for proximal femoral reconstruction.

The use of pedicle screw-rod system for the posterior fixation in cervico-thoracic junction.

OBJECTIVE: In cervico-thoracic junction (CTJ), the use of strong fixation device such as pedicle screw-rod system is often required. Purpose of this study is to analyze the anatomical features of C7 and T1 pedicles related to screw insertion and to evaluate the safety of pedicle screw insertion at these levels. METHODS: Nineteen patients underwent posterior CTJ fixation with C7 and/or T1 included in fixation levels. Seventeen patients had tumorous conditions and two with post-laminectomy kyphosis. The anatomical features were analyzed for C7 and T1 pedicles in 19 patients using computerized tomography (CT). Pedicle screw and rod fixation system was used in 16 patients. Pedicle violation by screws was evaluated with postoperative CT scan. RESULTS: The mean values of the width, height, stable depth, safety angle, transverse angle, and sagittal angle of C7 pedicles were 6.9 +/- 1.34 mm, 8.23 +/- 1.18 mm, 30.93 +/- 4.65 mm, 26.42 +/- 7.91 degrees, 25.9 +/- 4.83 degrees, and 10.6 +/- 3.39 degrees. At T1 pedicles, anatomic parameters were similar to those of C7. The pedicle violation revealed that 64.1% showed grade I violation and 35.9% showed grade II violation, overall. As for C7 pedicle screw insertion, grade I was 61.5% and grade II 38.5%. At T1 level, grade I was 65.0% and grade II 35.0%. There was no significant difference in violation rate between the whole group, C7, and T1 group. CONCLUSION: C7 pedicles can withstand pedicle screw insertion. C7 pedicle and T1 pedicle are anatomically very similar. With the use of adequate fluoroscopic oblique view, pedicle screw can be safely inserted at C7 and T1 levels.

Pelvis and extremity osteosarcoma with similar tumor volume have an equivalent survival.

BACKGROUND AND OBJECTIVES: The poor prognosis of pelvic osteosarcoma is well recognized, but the cause of this prognosis has not been well defined. METHODS: We analyzed the clinicopathologic characteristics of pelvic osteosarcoma, and their prognostic significances in a cohort of 41 patients, treated either surgically by ablation or non-surgically. In a separate case-controlled study, the 20 surgically treated osteosarcoma patients were matched with 38 patients with extremity osteosarcoma by tumor volume and age. RESULTS: The 5-year overall survival rates of the surgically and the non-surgically treated pelvic osteosarcoma were 55.8 +/- 13.0% and 4.8 +/- 4.7%, respectively (P < 0.01). Non-surgically managed pelvic osteosarcoma group were found to have a larger tumor volume (P = 0.02), bladder displacement and sacroiliac joint involvement (P < 0.01). The 5-year metastasis free survival rates in the surgically treated pelvic and extremity osteosarcoma were no different (41.4 +/- 12.8% vs. 48.6 +/- 8.4%), and histologic responses to chemotherapy were similar in two groups. CONCLUSIONS: No significant difference in survival or histologic response was found between the surgically treated pelvic and the extremity osteosarcoma with suitable tumor volume. Outcome of pelvis osteosarcoma corresponds to the poor survival of extremity osteosarcoma of high initial tumor burden.

Can bone scintigraphy predict the final outcome of pasteurized autografts?

OBJECTIVE: As pasteurization is becoming more widely used in limb salvage reconstruction, more study is required to understand about host-graft junction healing, graft revascularization and incorporation, and the incidence and type of complications among pasteurized autografts. This was mainly achieved by follow-up radiography. We aimed to clarify whether Tc99m bone scanning can be considered a reliable method in determining these three parameters. MATERIALS AND METHODS: Twenty-seven osteosarcoma patients with pasteurized autograft reconstructions were retrospectively reviewed using available scintigraphic and radiographic follow-up every 6 months postoperatively for 36 months. Follow-up of the unhealed cases was continued for the maximum follow-up period available for each case beyond the original study period, ranging from 1 to 15 months. Tc99m uptake was classified as cold, faint, moderate and high uptake. Junction healing was classified as none, partial and complete healing. RESULTS: Seventy percent of junctions united with a mean of 22 months. Ninety to 100% of junctions showed increased uptake (high or moderate) at one time of the study regardless of final outcome. 85% of the pasteurized grafts showed the characteristic "tramline appearance". Four grafts (15%) were complicated: pseudoarthrosis and implant failure (1), fractured plate (1), intramedullary nail (IMN) fracture (1), and prosthesis stem loosening in the host bone (1), with underlying unhealed junctions in all cases. CONCLUSION: Bone scanning can determine the stages of the graft's rim revascularization and incorporation; however, it cannot detect or predict junction healing or occurrence of complications. Supplementary treatment of unhealed junctions showing either decreased junctional uptake or graft quiescence may be warranted. Otherwise, detection of distant metastasis and early local recurrence remains the main application of Tc99m scanning in the management of bone sarcomas.