Biomechanical analysis of the Medoff sliding plate.

BACKGROUND: A new device for fixation of hip fractures the Medoff plate was biomechanically tested and compared with the Ambi plate and Gamma nail. METHODS: Six pairs of human cadaveric femurs were used. The characteristics evaluated were structural stiffness, strain distribution, and modes of failure. Results were compared with the Ambi plate and Gamma nail biomechanical studies from a previous study that used the same methods. RESULTS: The Medoff plate was stiffer than the other two implants for intertrochanteric fractures, and for segmental subtrochanteric fracture. The Medoff plate was more load sharing than the other implants in these fracture configurations. The mean load to failure was lower than for the Ambi plate or the Gamma nail. CONCLUSION: The Medoff plate is a better load-sharing device than the Ambi (DHS) or Gamma nail systems. The main concern is its structural weakness. The implant failed at loads 50% less than other devices. The greatest risk of implant failure is with unstable subtrochanteric fractures.

Salvage after severe lower-extremity trauma: are the outcomes worth the means?

Advances in reconstructive surgery have allowed for impressive salvage after severe lower-extremity trauma but not without complications when compared with immediate below-knee amputation. Several amputation index scores have been developed to help predict successful salvage as defined by a viable rather than a functional extremity. The purpose of this study was to evaluate retrospectively the predictive value of the amputation index scores and to assess prospectively overall health status and specific dysfunction in successful limb salvage and primary and secondary amputation by administering standardized generic and specific outcomes questionnaires (Medical Outcomes Study 36-Item Short-Form Health Survey, Western Ontario and MacMaster Universities Osteoarthritis Index). A retrospective chart review identified 55 severe lower-extremity injuries (Gustilo Type IIIB and IIIC) over a 12-year period (1984 to 1996). Forty-six severe open tibial fractures in 45 patients underwent attempted salvage. All required soft-tissue coverage by either local or free flap or vascular repair for leg salvage. The attempted-salvage group was subdivided into successful salvage and secondary amputation. The other nine patients underwent a primary amputation. There were no statistically significant differences in terms of patient demographics or other injuries (Injury Severity Score) in the three groups. Forty-eight of 54 patients with an average 5-year follow-up completed a validated generic and specific outcomes health questionnaire. In the attempted-salvage group, 89 percent of patients had a successful salvage and 11 percent came to a secondary amputation. The amputation index scores correctly predicted an amputation in 32 percent of patients. The magnitude of the amputation index scores did not correlate with the physical outcomes scores and were not found to add any significant value of information to the surgeon's decision making. Patients undergoing primary and secondary amputation had a worse physical outcomes score (28 versus 38) than successful salvage (p < 0.007). Even so, the SF-36 (physical component score) outcomes score for this group of injured extremities, regardless as to whether salvaged or amputated, was as low as or lower than that of many serious medical illnesses, suggesting that severe lower-extremity trauma impairs health as much as or more than being seriously ill. The mental component score in this group was comparable to that of a healthy population (49 versus 50), which implies the disability is primarily physical rather than psychological. Ninety-two percent of patients preferred their salvaged leg to an amputation at any stage of their injury, and none would have preferred a primary amputation.

The long-term success of fresh, small fragment osteochondral allografts used for intraarticular post-traumatic defects in the knee joint.

Ninety-two fresh osteochondral allografts were implanted in 91 patients with posttraumatic osteoarticular defects of the knee joint. These patients have been prospectively followed since 1972. An analysis of long-term survival of these grafts has been performed to determine their success rates: 75% at 5 years, 64% at 10 years, and 63% at 14 years. An evaluation was made between unipolar grafts, which involve only one surface of the compartment, and bipolar grafts, which involve both surfaces. The unipolar grafts had a lower failure rate at all time periods compared to bipolar grafts, with 76% survival at 5 years, 69% at 10 years, and 67% at 14 years. While investigating other factors that might affect the survival of the fresh osteochondral allografts, we calculated the influence of the anatomical location of the graft, patient sex, and patient age. There was no meaningful impact on allograft survival by either the location of the allograft or the sex of the patient. However, there was a significant effect on allograft longevity in terms of patient age, with patients under age 60 doing better. The best indication for the use of unipolar fresh osteochondral allografts is for posttraumatic defects in relatively young, active patients. Joint malalignment should be corrected to achieve best results.