Biomedical subjects

Ormonde M Mahoney

Publications and source records attributed to Ormonde M Mahoney.

6 recordsLinked to original sources

PubMed2006

Two-year experience using a limited-incision direct lateral approach in total hip arthroplasty.

We evaluated clinical, radiographic, and short-term recovery outcomes in an 18-month 1 surgeon series of 102 unilateral primary total hip arthroplasties performed by direct lateral approach through standard size (15-20 cm) and limited (<10 cm) incisions. Patients were blinded to incision type. Observed measures related to hematological status, transfusions, operative time, hospitalization time, narcotic use, rehabilitation, and discharge disposition did not appear to differ by incision type. Components were well placed in both groups. Intraoperative femoral fractures occurred in 2 limited-incision cases. At 2 years' minimum follow-up, we did not observe evidence that minimally invasive surgical technique provided clinically significant benefit to these patients.

Adult↗

PubMed2006

Biomechanical differences exhibited during sit-to-stand between total knee arthroplasty designs of varying radii.

The purpose of the study was to investigate the influence of the mechanical differences between a single-radius total knee arthroplasty (SR TKA) and a multi-radius (MR) TKA design on the functional performance during a sit-to-stand movement. Three-dimensional kinematics and electromyography for selected knee flexor and extensor muscles were obtained for 16 (8 SR and 8 MR) unilateral, posterior-stabilized TKA participants. Compared to the SR group, the MR group demonstrated compensatory adaptations, with increases in performance time, trunk flexion displacement and velocity, and knee extensor electromyography; and greater relative hamstring co-activation of the MR limbs was needed to increase joint stability. An initial knee abduction displacement was exhibited by more MR than SR participants. In conclusion, SR TKA provides functional benefits to patients.

Aged↗

PubMed2006

Modular femoral offset stems facilitate joint line restoration in revision knee arthroplasty.

UNLABELLED: Restoration of proper joint line position in revision total knee arthroplasty is essential in promoting recovery of function. We retrospectively analyzed joint line restoration and clinical outcomes in 22 consecutive femur revision cases using modular offsets of variable length and direction between the intramedullary fixation rod and the femoral component. Flexion and extension gap balancing techniques and medial epicondylar referencing was used to achieve proper position of the joint line. Position of the reconstructed joint line from postoperative radiographs was compared to the baseline position of intended anatomic placement determined from pre-operative planning radiographs. Postoperative joint line height averaged 1.6 mm distal to baseline (range, 5 mm distal to 2.5 proximal). Joint line was restored to within 2 mm of anatomic position in 12 of the 22 knees. Sixteen patients received conventional, minimally constrained tibial inserts, and joint stability was achieved in all cases. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series). See Guidelines for Authors for a complete description of levels of evidence.

Adult↗

PubMed2005

Reconstructed hip joint position and abductor muscle strength after total hip arthroplasty.

We evaluated 60 limbs in 30 patients with unilateral primary total hip arthroplasty and nondiseased contralateral hip. The ratio of femoral offset (FO) to the body weight lever arm (FO ratio) and the ratio of the height of hip center (HC) to pelvic height (HC ratio) were calculated on radiographs. Isometric hip abductor strength was measured by dynamometer. The ratio of normalized strength of the reconstructed side to that of the nonoperated side was calculated (strength ratio). The FO ratio correlated positively to the strength ratio (r = 0.491; P = .0059), whereas the HC ratio correlated negatively (r = -0.568; P = .0011). Slight increase of FO ratio along with restoration of normal hip joint center erring on the side of slight inferomedial cup positioning appeared to optimize hip abductor function.

Aged↗

PubMed2003

Surface damage on open box posterior-stabilized polyethylene tibial inserts.

Twenty retrieved Scorpio posterior-stabilized implants were available for analysis. The mean implantation time was 22 months (range, 2 days-42 months). Favorable types and amounts of surface damage were seen on the tibiofemoral and backsides of these modular PE liners that had been packaged in an inert environment and then sterilized by gamma irradiation. Delamination represented only 0.1% of the total surface damage. Off-axis loading (varus malalignment) was associated with tibial component loosening but there was no evidence of peripheral damage of PE caused by edge loading. With this open-box design, hyperextension marks on the anterior aspect of the posterior-stabilized post from femoral component impingement occurred in 11 of 20 cases and was related to sagittal component positioning: excess tibial slope or increased tibial slope combined with a flexed femoral component. Unique coarse abrasions occurred in 16 of 20 cases and were the result of cement extrusion into the open box, especially with varus malalignment. These observations provide guidance for optimizing the surgical technique and the design of posterior-stabilized total knee components.

Adult↗

PubMed2002

The effect of total knee arthroplasty design on extensor mechanism function.

The effect of total knee arthroplasty design on extensor mechanism function was evaluated prospectively in a consecutive, single-surgeon series. Group 1 knees (n = 83) were implanted with a prosthesis that has a multiradius femoral component, and group 2 knees (n = 101) were implanted with a femoral prosthesis that has a single flexion-extension axis. Group 2 knees gained flexion more rapidly: At 6 weeks, the average flexion for was 94.5 degrees for group 1 and 107.1 degrees for group 2 (P<.001). Significantly more patients with group 2 knees were able to arise from a 16-inch (low) chair without using their arms starting at 6 weeks, and a difference was maintained through 2 years (90% vs 73%; P=.003). Patients with group 2 knees had significantly less anterior knee pain when rising from a seated position starting at 6 weeks, and a difference was maintained through 2 years (1% vs 22%; P=.001).

Aged↗