Faculty Bibliography

CD271 has been applied to isolate mesenchymal stem cells (MSCs) from bone marrow and other tissues. Umbilical cord blood is a unique resource of stem cells and endothelial progenitor cells. Isolation of MSCs from umbilical cord blood, however, has been inefficient and inconsistent. This study was designed to examine the potential application of CD271 as a marker for the isolation of MSCs from umbilical cord blood. CD271+ cells were isolated from umbilical cord blood and bone marrow using CD271 antibody-conjugated microbeads, and characterized in osteogenic, chondrogenic and adipogenic differentiation. CD271+ cells from umbilical cord blood were slow to proliferate compared with those isolated from bone marrow. While CD271+ cells from bone marrow differentiated into osteogenic, chondrogenic and adipogenic lineages, there were no sound indications of differentiation by CD271+ cells from umbilical cord blood under the same differentiation conditions applied to the CD271+ cells from bone marrow. The study also found that bone marrow CD271+ cells remarkably upregulated the expression of chondrogenic genes under chondrogenic differentiation induction. When implanted into bone defects in mice, CD271+ cells from bone marrow regenerated significant bone, but the counterparts in umbilical cord blood formed little bone in the bone defects. In conclusion, CD271 is an efficient marker for MSC isolation from bone marrow but has failed to isolate MSCs from umbilical cord blood. CD271+ cells in bone marrow are particularly chondrogenic. The property of CD271+ cells is unique but varies from different tissues.

Standard 4-strand repair of Achilles tendon tears is effective, but additional strength may be desirable in patients who are compromised or those with reruptures. Use of a xenograft scaffold has not been investigated biomechanically in Achilles tendon repair. This study compared stiffness, gap formation, and ultimate load to failure with Krackow repair vs Krackow repair augmented with xenograft scaffold in 6 matched pairs of fresh-frozen human lower extremities. The Achilles tendon was transected 4 cm above the calcaneal insertion. Specimens were randomized to receive standard Krackow repair or Krackow repair augmented with a porcine xenograft scaffold. The graft was wrapped around the repaired tendon, sutured to itself with 2-0 FiberWire (Arthrex, Naples, Florida), and attached to the tendon distally and proximally and then medially and laterally. Specimens were loaded for 200 cycles between 5 and 30 N. Load to 5-mm gapping and load to ultimate failure were measured. Xenograft scaffold augmentation of standard Krakow Achilles tendon repair was significantly stronger and stiffer than standard Krackow repair in a biomechanical model immediately after repair (39.0±8.8 vs 24.4±4.6 N/mm; P=.01). The augmented repair group had significantly higher load to ultimate failure than did the Krackow group (862.7±174.0 vs 479.5±65.5 N; P<.01). Biological factors remain to be investigated, but this augmentation method could provide additional strength in patients who are compromised or those with reruptures.

BACKGROUND:It may be possible to avoid malleolar osteotomy for treatment of osteochondral talar lesions with chondrocyte transplantation techniques, where perpendicular approach to the talar surface is not required. We hypothesized that limited anterior distal tibial plafondplasty would allow access to most of the talar surface. We compared talar access with soft tissue exposure versus plafondplasty. METHODS:Two soft tissue exposures (anteromedial and anterolateral) and two limited anterior distal tibial plafondplasties (anteromedial and anterolateral) were used on 12 cadaver lower-extremity specimens. Digital analysis was used to assess the accessible area. RESULTS:Percentage of total talar dome surface area access increased significantly between soft tissue exposure and limited plafondplasty medially (22.3 +/- 6.3% versus 37.9 +/- 4.6%; p < 0.001) and laterally (22.4 +/- 7.7% versus 37.9 +/- 7.7%; p < 0.001). Percentage sagittal plane access also increased significantly between soft tissue exposure and limited plafondplasty medially 54.4 +/- 12.0% versus 81.3 +/- 9.7%; p < 0.001) and laterally (53.3 +/- 14.5% versus 80.9 +/- 12.8%; p < 0.001). Limited exposure to an additional 14.2 +/- 5% of the total talar surface area was possible. The posterior 10.6 +/- 8% was inaccessible. CONCLUSIONS:A soft tissue approach with limited plafondplasty provided adequate exposure for the majority of the medial and lateral talar surface. Only the central posterior 10% of the talus was not accessed by this method. CLINICAL RELEVANCE/CONCLUSIONS:It may be possible to avoid malleolar osteotomy by using limited plafondplasty to access the talar dome for treatment of osteochondral lesions if perpendicular access to the talus is not required.

BACKGROUND:We compared forefoot and calcaneocuboid pressure in isolated medial column fusion (1-3 tarsometatarsal fusion) versus medial and lateral column fusion (1-5 tarsometatarsal fusion) in a neutral, inversion, and eversion loading model in stance gait phase. METHODS:Twelve fresh-frozen cadaveric specimens were cyclically loaded to 720 N at 0.5 Hz for 30 cycles. Plantar and calcaneocuboid joint pressures were measured in neutral, inversion, and eversion in the intact foot, with isolated medial column fusion, and with medial and lateral column fusion. RESULTS:Lateral pressure was higher in the medial and lateral column fusion group than isolated medial column fusion and intact in neutral (55.8 +/- 14.8 versus 46.2 +/- 13.6 and 45.5 +/- 14.8 kPa, respectively) and eversion (80.7 +/- 18.4 versus 61.8 +/- 13.7 and 60.2 +/- 18.2 kPa, respectively) (p < or = 0.001). Calcaneocuboid pressure was higher in medial and lateral column fusion than isolated medial column fusion and intact in neutral (1436.7 +/- 210.6 versus 1073.7 +/- 282.5 and 1084.9 +/- 337.6, respectively; p = 0.001) and inversion (1518.3 +/- 270.5 versus 1310.5 +/- 298.8 and 1237.1 +/- 401.9, respectively; p = 0.02). Using combined position data, calcaneocuboid pressure was significantly higher in the medial and lateral column group than in both other groups. The isolated medial column fusion group did not differ significantly from the intact group in any measurement. CONCLUSION/CONCLUSIONS:Medial and lateral column fusion significantly increased lateral and calcaneocuboid pressures with loading compared with isolated medial column fusion and the intact state. No difference was observed between isolated medial column fusion and the intact state. CLINICAL RELEVANCE/CONCLUSIONS:It may be advisable to avoid fusing the lateral column in tarsometatarsal arthrodesis if possible to avoid pressure increase in the forefoot and hindfoot.

Interdigital neuralgia affects a significant number of individuals, with an average age of presentation in the sixth decade and a 4- to 15-fold increased prevalence in women. Historical descriptions date back to the 19th century. Nonoperative treatment with shoe modifications, metatarsal pads, and injections provides relief for most, but long term, 60% to 70% of patients eventually elect to have surgery. Although excision can be performed through a dorsal or plantar approach, we prefer the dorsal incision to prevent scar formation on the plantar aspect of the foot. Satisfactory results are common but not certain with reports of excellent or good ranging from 51% to 93%.