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Complete rupture of the origin of the hamstrings is an uncommon injury. Primary surgical repair is the treatment of choice, but in some not possible. We present a case of an avid cyclist who had significant disability from a 6-year-old injury. He underwent reconstruction with Achilles allograft and suture anchors. With the knee flexed to 90 degrees and after extensive mobilization, the retracted musculotendinous unit would not reach the ischial tuberosity. Two suture anchors were placed in the ischial tuberosity after soft tissue debridement. One limb of suture from each anchor was placed in the end of an Achilles allograft with a locking suture, with the other end used to pull the end of the graft to the ischial tuberosity. An additional suture was placed in running fashion down each side of the graft. Distally, the graft was fanned out and attached to the retracted hamstrings with interrupted sutures with the knee at 40 degrees and maximal proximal pull on the hamstrings. The patient outcome was excellent. He resumed high level cycling by 6 months after surgery with no symptoms. Isokinetic testing demonstrated a hamstring deficit of 25% at 60 degrees/s, and 20% at 180 degrees/s at 8 months.

We present the results of experimental determination of the heat capacity of the pyrochlore Er 2 Ti 2 O 7 as a function of temperature (0.35–300 K) and magnetic field (up to 9 T), and for magnetically diluted solid solutions of the general formula (Er 1− x Y x ) 2 Ti 2 O 7 ( x ≤0.471). On either doping or increase of magnetic field, or both, the Néel temperature first shifts to lower temperature until a critical point above which there is no well-defined transition but a Schottky-like anomaly associated with the splitting of the ground state Kramers doublet. By taking into account details of the lattice contribution to the heat capacity, we accurately isolate the magnetic contribution to the heat capacity and hence to the entropy. For pure Er 2 Ti 2 O 7 and for (Er 1− x Y x ) 2 Ti 2 O 7 , the magnetic entropy as a function of temperature evolves with two plateaus: the first at R ln ⁡ 2 , and the other at R ln ⁡ 16 . When a very high magnetic field is applied, the first plateau is washed out. The influence of dilution at low values is similar to the increase of magnetic field, as we show by examination of the critical temperature versus critical field curve in reduced terms.

Objective:In this study, we applied a spring-loaded impactor to deliver traumatic forces to articular cartilage in vivo. Based on our recent finding that a 0.28-J impact induces maximal catabolic response in adult bovine articular cartilage in vitro using this device, we hypothesize that this impact will induce the formation of a focal osteoarthritic defect in vivo.Design:The femoral condyle of New Zealand White rabbits was exposed and one of the following procedures performed: 0.28 J impact, anterior cruciate ligament transection, articular surface grooving, or no joint or cartilage destruction (control). After 24 hours, 4 weeks, or 12 weeks (n = 3 for each time point), wounds were localized with India ink, and tissue samples were collected and characterized histomorphometrically with Safranin O/Fast green staining and Hoechst 33342 nuclear staining for cell vitality.Results:The spring-loaded device delivered reproducible impacts with the following characteristics: impact area of 1.39 ± 0.11 mm2, calculated load of 326 ± 47.3 MPa, time-to-peak of 0.32 ± 0.03 ms, and an estimated maximal displacement of 25.1% ± 4.5% at the tip apex. The impact resulted in immediate cartilage fissuring and cell loss in the surface and intermediate zones, and it induced the formation of a focal lesion at 12 weeks. The degeneration was defined and appeared more slowly than after anterior cruciate ligament transection, and more pronounced and characteristic than after grooving.Conclusion:A single traumatic 0.28 J impact delivered with this spring-loaded impactor induces focal cartilage degeneration characteristic of osteoarthritis.