Different femoral designs in TKA have shown multiple effects on the conformity of the patella-femoral joint. Historically, this anatomical relationship may interfere with clinical results. The objective of this study was to compare the reproducibility of a correct patello-femoral conformity in patients underwent TKA utilizing modern femoral implants.

Introduction: The objective of this study was to evaluate the biomechanical proprieties of a hip resurfacing system in terms of failure of the implant with different positioning of the prosthesis in cadaveric femurs.

Materials and Methods: The study has been divided in 3 phases. First phase: Six-teen cadaveric femurs were tested to failure using a standard MTS device once the Conserve Plus (Wright Medical) system was implanted: 8 femurs after a 4mm notching of the neck and 8 contralateral without notching. Second phase: Six-teen cadaveric femurs were tested using a 210 Kg axial load: 8 with the Conserve Plus system implanted at 140° and 8 contralateral with 10° of varus. Third phase: Eight femurs were tested with the implant having 10 ° of excessive antiversion of the component and 8 with the implant having 10 ° of excessive retroversion. The control group was represented by 16 femurs having the system implanted following the natural version of the femoral neck.

Results: An average of 4865 Newtons(N) was necessary for the failure of the implant after notching, compared to 7043 N without notching. The varus alignment of the implant showed a statistical different increase of the stress on the femoral neck: 15% postero-superiorly and 21% antero-superiorly. The neutral alignment at 140° showed a decrease of the overall stress on the femoral neck. Adding 10 ° of excessive anteversion or retroversion did not show any statistical difference in terms of failure of the implant when compared to the anatomical alignment.

Conclusions: This biomechanical study showed that the correct positioning of the implant represents a fundamental requirement for the success of the hip resurfacing procedure. The notching of the neck decreases significantly the biomechanical proprieties of the implant, while the varus alignment increases the stress on the superior neck cortex.

Objective: The treatment of Anterior Cruciate Ligament (ACL) instability resulting from incomplete tears or elongation in continuity has been historically treated either conservatively or by graft replacement. The literature is sparce with regard to alternative reparative surgical treatment of this condition. We report our early experience using a thermal shrinkage treatment on 11 consecutive knees suffering from this condition in patients experiencing continuing instability.

Methods: Eleven patients underwent ACL electrothermal monopolar treatment at our institution between 1998 and 1999. All of these patients presented a difference of 6 mm or more when comparing the involved to the uninvolved side using KT-1000 evaluation. They showed ACL incomplete tears or elongation in continuity at the time of the arthroscopic evaluation. A single electrothermal device (Oratec, Oratec Interventions, Menlo Park, CA) was used in all of the cases. Rehabilitation protocol included immobilization and non-weight-bearing for 6 weeks. A one-year minimum follow-up study was conducted in all of the patients following the IKDC rating system.

Results: The overall outcome at a one-year minimum F.U. was normal or nearly normal in all of the patients. They also showed a 30 pound side to side difference less than 5 mm. They were allowed to return to running 3 months after ACL shrinkage and to full unrestricted sports after 6 months.

Conclusions: The thermal repair of ACL-insufficient knees represents an emerging alternative treatment to standard techniques. The primary controindication for this technique is discontinuity of the ligament. Particular attention must be paid to patient compliance during ligament healing in its early stages.

Objective: Bone-patellar tendon-bone (BPTB) and Achilles tendon allografts have been widely used in primary and revision ACL reconstructions showing good results comparable to those with autografts. The literature is sparce with regard to treatment and results of primary ACL reconstruction using Achilles tendon alone. The objective of this study was to present the clinical outcome of 50 consecutive primary ACL reconstructions with Achilles allograft utilizing interference screws fixation. Particular attention was dedicated to the incidence of tunnel widening and graft rejection phenomenon.

Methods: Fifty consecutive patients had primary ACL reconstruction using fresh frozen Achilles tendon allografts from 1997 to 1998 at our institution. All grafts were sterilely harvested and none of them were subjected to secondary sterilization. All procedures were performed using interference screws fixation. A two-year minimum follow-up study was conducted in all of the patients: clinical and functional evaluation was performed according to the International Knee Documentation Committee (IKDC) by an independent examiner. All patients were evaluated using the KT-1000 arthrometer at 30 pounds of force: data was reported as an injured-to-uninjured difference. Lateral and 45° posteroanterior weightbearing radiographs were performed in each patient. The sclerotic margins of the tibial tunnel were measured at the widest dimension by a single observer and were compared with the initially drilled tunnel size.

Results: According to the IKDC rating system, the overall outcome was normal or nearly normal in 96% of the patients. Forty-eight patients had a 30 pound side to side difference £ 5 mm. None of the patients had greater than a 10 mm difference. There was no evidence of graft rejection from an immune response or disease transmission. On the femoral side, all bone plugs appeared to be incorporated radiographically. The average allograft tibial tunnel enlargement at the widest level was 1.9 mm (0 to 5 mm) in the posteroanterior view and 1.7 mm (−0.2 to 5 mm) in the lateral view.

Conclusion: Our results suggest that fresh frozen Achilles tendon allografts represent a good alternative in primary ACL reconstructions. No significant difference was seen in KT-1000 arthrometer measurements and clinical outcomes between patients with different tibial tunnel widening. We believe that fixation with interference screws could reduce the incidence of this undesirable phenomenon.