Biomedical subjects

J C Wolchok

Publications and source records attributed to J C Wolchok.

6 recordsLinked to original sources

PubMed1998

The effect of intersegmental knee moments on patellofemoral contact mechanics in cycling.

The aim of this study was to evaluate the effect of bicycle pedal design on the mechanics of the patellofemoral joint. Previous research determined that for certain riders the non-driving varus and internal knee moments could be reduced by switching from fixed to free floating pedals (Ruby and Hull, 1993). It was postulated that the presence of varus and internal knee moments during fixed pedal cycling may adversely affect patellofemoral joint contact mechanics which could lead to the development of anterior knee pain. To investigate the effect of pedal design the hypothesis that varus and internal intersegmental knee moments significantly increase patellofemoral contact pressure, contact area and contact force was tested. To test this hypothesis cycling loads were simulated in vitro using a six-degree-of-freedom load application system (LAS). Using the LAS, varus moments ranging from 0-20 Nm and internal knee moments ranging from 0-10 Nm were applied simultaneously with quadriceps force at knee flexion angles of 60 and 90 degrees. Patellofemoral contact patterns were measured using pressure sensitive film. An applied 10 Nm internal moment significantly increased both contact area by 16% and contact force by 22% at 90 of flexion. The application of a 20 Nm varus moment modestly yet significantly increased contact area by 6% and contact force by 5%. When applied in combination, varus and internal knee moments increased contact area and force by as much as 29% and 28% respectively. The mean contact pressure was not significantly increased by either of the two moments. The results suggest that non-driving intersegmental knee moments subject the patellofemoral joint to loads and contact patterns which may accelerate the development of chondromalacia.

Aged↗

PubMed1998

Arthroscopic Lachman test: a new technique using anatomic references.

Using familiar anatomic references viewed during a standard arthroscopic evaluation, an arthroscopic Lachman test can help the surgeon identify anterior cruciate ligament deficiency. This test is especially useful in those patients where a false-negative report as a result of guarding, meniscal tears or other factors is suspected. Additionally, this test can be used after anterior cruciate ligament reconstruction to verify that the abnormal anterior laxity has been eliminated.

Anterior Cruciate Ligament Injuries↗

PubMed1997

Consistent and accurate graft passage and interference screw guide wire placement during single incision anterior cruciate ligament reconstruction.

Misplacement and misalignment of trocar pins and guide wires during single-incision anterior cruciate ligament reconstructions can lead potentially to a number of complications. These complications include unacceptable trocar pin exit locations, difficulty repositioning the trocar pin along the initial track after unsuccessful attempts at graft passage, as well as guide wire impingement and graft transection during interference screw advancement. To help overcome these complications, a surgical technique using an eccentric aimer and two-pin passer was developed to help provide precise and repeatable placement of both a trocar pin and guide wire.

Anterior Cruciate Ligament↗

PubMedDate not supplied

Extra-articular lateral reconstruction technique.

This article describes an anterolateral reconstruction procedure that, when used in combination with an intra-articular anterior cruciate ligament (ACL) reconstruction, restores rotary and anterior knee stability. We believe that failing to recognize lateral instabilities and to perform an extra-articular reconstruction is an under-recognized cause of failure of ACL reconstruction. We also describe the indications, medical histories, and physical examination tests used to determine when an anterolateral reconstruction is needed. One should suspect a compromise of the lateral structures when presented with a failed ACL reconstruction in which the tunnels, the graft, and the rehabilitation all seem to have been done properly, or when a prior lateral procedure has been attempted and failed. In our experience, if a second ACL reconstruction is undertaken without the benefit of a lateral reconstruction, it may fail as well.

Anterior Cruciate Ligament↗

PubMedDate not supplied

A postmortem examination of poly-L lactic acid interference screws 4 months after implantation during anterior cruciate ligament reconstruction.

This is a report of a postmortem examination of an implanted bioabsorbable interference screw used for patellar tendon graft fixation during anterior cruciate ligament reconstruction. Examination was conducted 4 months after implantation. Examination included radiographic, arthroscopic, and magnetic resonance evaluations as well as histologic and mechanical pullout testing. Examination showed no evidence of tunnel widening, lytic bone changes, or inflammatory or foreign body reaction. Pullout and histologic testing indicated that appropriate bone plug incorporation was occurring. We believe the results of this case suggest that the use of bioabsorbable poly-L lactic acid interference screws is a safe and efficacious alternative to metallic screws during anterior cruciate ligament reconstruction.

Adult↗

PubMedDate not supplied

The use of allografts in ligamentous reconstructions of the knee.

Our continuing experience with allografts has led us to the firm conclusion that there is a clear place for allografts in the ligamentous reconstruction of the unstable knee. Clearly, issues such as cost and availability will limit allograft usage, however concerns regarding inferior clinical results should not. Our experience and those reported by others, indicates that comparable clinical results can be obtained with the added benefit of reduced surgical morbidity. In all cases meticulous attention must be given to the surgical technique. When surgical accuracy is uniformly obtained, the graft choice becomes less important when considering the sole goal of obtaining ligamentous stability in the knee.

Achilles Tendon↗