Faculty Bibliography

BACKGROUND:Little has been reported about the biologic effect of shock waves on human normal or pathologic tendon tissue. We hypothesized that inflammatory cytokine and MMP production would be down-regulated by shock wave stimulation. MATERIALS AND METHODS/METHODS:Diseased Achilles tendon tissue and healthy flexor hallucis longus tissue were used. Shock wave treatment was applied to cultured cells at 0.17 mJ/mm(2)energy 250, 500, 1000, and 2000 times. RESULTS:A dose-dependent decrease in cell viability was noted in cells receiving 1000 and 2000 shocks (86.0 +/- 5.6%, p = 0.01 and 72.4 +/- 8.9%, p = 0.001) as compared with the normal control. Cell count in the 500-shock group increased by 23.4% as compared with the control (p = 0.05). The concentration of MMP 1, 2, and 13 was higher in diseased tenocytes as compared with normal cells (p = 0.04, all comparisons). IL-6 levels were higher in the diseased tenocytes as compared with normal tenocytes (44.10 +/- 16.72 versus 0.21 +/- 0.55 ng/ml, (p < 0.05). IL-1 levels in normal cells increased (2.24 +/- 5.02 ng/ml to 9.31 +/- 6.85 ng/ml) after shock wave treatment (p = 0.04). In diseased tenocytes, levels of MMP-1 (1.12 +/- 0.23 to 0.75 +/- 0.24 ng/ml; p = 0.04) and MMP-13 (1.43 +/- 0.11 to 0.80 +/- 0.15 ng/ml; p = 0.04) were significantly decreased after shock wave treatment. The IL-6 level in diseased tenocytes was decreased (44.10 +/- 16.72 to 14.66 +/- 9.49 ng/ml) after shock wave treatment (p = 0.04). CONCLUSION/CONCLUSIONS:Higher levels of MMPs and ILs were found in human tendinopathy-affected tenocytes as compared with normal cells. ESWT decreased the expression of several MMPs and ILs. CLINICAL RELEVANCE/CONCLUSIONS:This mechanism may play an important role in shock wave treatment of tendinopathy clinically.

Proliferation of cultured human fibroblasts and other types of cells has been shown to be hindered by exposure to local anesthetics, which are widely used in musculoskeletal medicine for their use in regional anesthesia, selective nerve blocks, bursography, and brisement. We hypothesized that bupivacaine would decrease cell proliferation and production of extracellular matrix components collagen and proteoglycan in healthy human tenocytes in culture. Primary human tenocyte cultures were prepared from samples of normal tendons obtained from healthy tissue that would otherwise have been discarded during lower extremity tendon transfer surgery. Samples were obtained from 6 patients, 5 women and 1 man with an average age of 69 years (range, 17-73 years). Five flexor digitorum longus tendon samples and 1 peroneus longus tendon sample were used. Harvested tendon tissues (5 mm(3)) were used as explants for primary cell cultures. To measure the proliferative response to bupivacaine, seeded cells were exposed to saline control or to various concentrations of bupivacaine in 1% fetal bovine serum DMEM/F12 or 10% fetal bovine serum DMEM/F12. The 1% fetal bovine serum medium demonstrated the pure bupivacaine effect, and 10% fetal bovine serum more closely approximated the in vivo environment. Seeded cells were starved of fetal bovine serum for 12 hours before exposure to phosphate-buffered saline (control group) and 500 microM bupivacaine (experimental group). This concentration of bupivacaine was selected because it was found to significantly hinder proliferation in both the 1% and 10% fetal bovine serum groups in our proliferation assay. Tenocyte proliferation and extracellular matrix component production were significantly lower (P<or=.05) at >or=1 time points up to 6 days in bupivacaine-treated groups as compared with controls.

Injection into the posterior subtalar joint has not been validated for accuracy using radiographic end points. We asked whether needle placement into a normal posterior subtalar joint could be performed accurately and selectively by experienced surgeons without fluoroscopic guidance. Three fellowship-trained orthopaedic foot and ankle surgeons each injected the posterior subtalar joint of 20 cadaveric specimens using an anterolateral approach. Fluoroscopic images were obtained by an independent investigator and blinded. A separate fellowship-trained foot and ankle surgeon interpreted the images. Of 60 injections, 58 were accurate and two were extraarticular based on interpretation by an independent foot and ankle surgeon. Extravasation into the ankle occurred in 14 samples and into the peroneal sheath in two samples. Experienced surgeons can place intraarticular injections into a radiographically normal posterior subtalar joint without fluoroscopy with a high degree of accuracy. However, extravasation into the ankle or peroneal tendon sheath occurred in an unpredictable fashion, suggesting selectivity of injection placement is relatively limited without the use of fluoroscopy. Fluoroscopy may not be necessary for injections used solely for therapeutic purposes. However, if the injection is intended for diagnostic purposes or to assist in surgical decision-making or if the joint is abnormal, we recommend fluoroscopy to ensure the subtalar joint is the only anatomic structure impacted by the injection.

BACKGROUND:Elongation of ligaments during early mobilization after reconstruction may be associated with decreased stability. We evaluated elongation of the anterior talofibular ligament (ATFL) before and after lateral ligament reconstruction within a physiologic range of motion with protected and unprotected, isolated dorsiflexion/plantarflexion range of motion. MATERIALS AND METHODS/METHODS:Six fresh frozen cadaver legs were used with the ATFL meticulously dissected. A differential variable reluctance transducer (DVRT) was spaced to span the course of the ATFL using consistent placement points based on previous reports. Elongation was measured in a load frame with protected motion of 30 degrees plantarflexion and 10 degrees dorsiflexion for the intact and sectioned ATFL and for the repaired specimen with and without protected motion. The proximal DVRT anchor point was detached for sectioning and repair of the ATFL and replaced at the same position. Testing was 1000 cycles at 1 Hz for the repaired protected specimen and 10 cycles at 1 Hz for all other stages. RESULTS:Initial elongation in the unprotected, repaired group was significantly higher than initial elongation in the intact (p < 0.01), sectioned (p = 0.02), and repaired, protected (p < 0.01) groups. Final elongation in the unprotected repaired group was also higher than final elongation in all other groups (p < 0.01 for all comparisons). CONCLUSION/CONCLUSIONS:The use of protected range of motion of the ankle after lateral ankle ligament reconstruction was not associated with elongation of the ATFL. The ATFL elongated significantly by comparison without protected dorsiflexion/plantarflexion. CLINICAL RELEVANCE/CONCLUSIONS:The study provides biomechanical support for the safety of early protected dorsiflexion/plantarflexion range of motion after Broström reconstruction.

BACKGROUND:The effect of the Cotton osteotomy has not been studied in isolation, and no alternative to bone graft has been investigated for this osteotomy. We hypothesized that there would be no difference in radiographic and pressure findings using the Cotton osteotomy with bone graft or an opening wedge block plate. MATERIALS AND METHODS/METHODS:Each specimen of eight matched pairs of lower extremities was loaded in simulated double-leg stance via pneumatic cylinders as described previously. Weightbearing lateral and anteroposterior radiographs and medial and lateral pressure measurements were obtained for all intact specimens. Specimens were randomly assigned to receive a Cotton osteotomy with a dorsal opening wedge allograft or an opening wedge plate. Each specimen was cycled at 3 Hz to 720 N for 5000 cycles and measurements were repeated. RESULTS:Calcaneal pitch was lower after the block plate procedure (mean +/- standard error of the mean) (intact, 23.4 +/- 1.2 degrees versus post-procedure, 21.8 +/- 1.1 degrees; p = 0.05). There was a significant difference (p < 0.05) in percentage of total plantar pressure medially and laterally between the intact specimen and the specimen after osteotomy with both methods. Pressure increased medially and decreased laterally. CONCLUSION/CONCLUSIONS:With the numbers available, these methods for performing a Cotton osteotomy did not differ in addressing lateral column overload. CLINICAL RELEVANCE/CONCLUSIONS:Dorsal opening wedge medial cuneiform osteotomy performed with femoral head allograft or a block plate may be effective both in reducing lateral column pressures and increasing medial column pressures when they are deficient preoperatively.

BACKGROUND:We hypothesized that a dorsomedial locking plate with adjunct screw compression would provide superior rigidity compared to crossed screws for first metatarsocuneiform (MTC) arthrodesis. MATERIALS AND METHODS/METHODS:In ten matched lower extremity pairs, specimens in each pair were randomly assigned to receive screw fixation or plate with screw fixation. Bone mineral density (BMD) was measured. For the crossed-screw construct, two 4.0-mm cannulated screws were used. One screw was inserted dorsal to plantar beginning from the first metatarsal 10 to 15 mm distal to the joint, and the second was inserted from the cuneiform 8 to10 mm proximal to the joint, medial to the first screw, into the first metatarsal. For the plate construct, a 4.0-mm cannulated compression screw was inserted from the dorsal cortex of the first metatarsal to the plantar aspect of the medial cuneiform. A locking plate was inserted dorsomedially across the MTC joint. Specimens were loaded in four-point bend configuration (displacement rate, 5 mm/min) until failure of the fixation or 3-mm deformation. An extensometer was used to measure deformation. RESULTS:There was no difference in load to failure or stiffness between the two groups. BMD was positively correlated with load to failure in the screw (r = 0.893, p = 0.001) and the plate (r = 0.858, p = 0.001) construct. CONCLUSION/CONCLUSIONS:The plate construct with compression screw did not show different rigidity as compared with the screw construct with the numbers available. CLINICAL RELEVANCE/CONCLUSIONS:Further investigation of a dorsomedial plate with adjunct screw compression may be warranted for first MTC arthrodesis.

BACKGROUND:Obtaining adequate fixation during tibiotalocalcaneal (TTC) arthrodesis may be challenging. Various fixation constructs have been tested biomechanically, but the use of a locking plate has not been reported. We hypothesized that the locking plate with a TTC augmentation screw would provide structural rigidity comparable to that of the intramedullary (IM) nail with a TTC augmentation screw during dorsiflexion testing. MATERIALS AND METHODS/METHODS:Six matched pairs of fresh frozen cadavers underwent TTC arthrodesis. Specimens in each pair were randomized to receive a locking plate or an intramedullary nail. Each specimen had an additional TTC augmentation screw through the calcaneus, talus, and medial tibia. All samples underwent dorsiflexion testing with determination of structural rigidity at the first cycle (initial rigidity) and last cycle (final rigidity) and the torque required to achieve a failure of 10 degrees of dorsiflexion. Statistical analysis was performed using a paired t-test to determine whether any differences were significant (p < 0.05). RESULTS:The locking plate construct showed higher final rigidity (mean +/- standard error of the mean) (27.7 +/- 2.6 N-m/degree versus 17.6 +/- 2.1 N-m/degree, p = 0.01) than the IM nail construct. There were no other differences measured. CONCLUSION/CONCLUSIONS:Rigidity with the the IM nail was inferior to that with locking plate fixation for TTC arthrodesis in one of the four parameters tested. CLINICAL RELEVANCE/CONCLUSIONS:Screw augmented IM nail fixation and augmented locking plate fixation may offer similar rigidity clinically for TTC arthrodesis.

BACKGROUND:We hypothesized that a locking plate would be stronger than a blade plate for tibiotalocalcaneal arthrodesis under dorsiflexion and torsional loading. MATERIALS AND METHODS/METHODS:Nine pairs of matched cadaveric lower extremities were used. BMD was obtained for each specimen. Each received a retrograde augmentation screw and a stainless steel LC-angled blade plate (Synthes, Paoli, PA) or a stainless steel LCP proximal humerus locking plate (Synthes, Paoli, PA). Specimens were cyclically loaded in dorsiflexion to simulate 6 weeks of partial weightbearing and then monotonically loaded to failure. Specimens were removed from the load frame and remounted to simulate fusion. The specimen received an axial load of 720 N and was externally rotated proximal to the construct at 5 degrees/sec to fracture. Data were compared with a Student's t-test. Pearson correlation analysis was used to determine whether bone mineral density was significantly related to measured parameters. Significance was set at p < or = 0.05. RESULTS:The locking plate group had higher initial stiffness, higher dorsiflexion and torsional load to failure, and lower construct deformation than the blade plate group. Bone mineral density was positively correlated with dorsiflexion failure load and torsional failure load in the locking plate construct. CONCLUSION/CONCLUSIONS:Fixation with the locking plate was superior to that with the blade plate. CLINICAL RELEVANCE/CONCLUSIONS:Use of a locking plate may be an effective fixation technique in tibiotalocalcaneal arthrodesis, especially in complex hindfoot reconstructions with bone loss or deformity.