G. Yves Laflamme

Causes of Early Failure in a Multicenter Clinical Trial of Hip Resurfacing

The purpose of this study was to evaluate the clinical outcomes and possible causes of early failure in a multicenter trial of metal-on-metal hip resurfacing. Two hundred patients were prospectively enrolled and followed for an average of 31.2 months (range, 12-54 months). Of 200 patients, 14 (7.0%) required revision surgery at a mean time of 19.5 months (range, 3-47 months). Patients with failures were significantly younger and heavier than the nonfailures, and all were male. Patients who were revised did not differ from those who were not revised in terms of radiographic outcomes, but they did report lower functional outcome scores at all preoperative and postoperative testing intervals. Most failures (10/14) were related to early acetabular loosening. The learning curve was likely a factor in these cup failures. This report highlights the importance of patient selection and surgical technique in hip resurfacing arthroplasty. It is anticipated that further surgical experience will lead to a reduction in this high early failure rate.

Trabecular Metal Used for Major Bone Loss in Acetabular Hip Revision

The purpose of this study was to evaluate the outcome of trabecular metal (TM) acetabular components used in revision hip arthroplasty with major bone deficiency. We retrospectively reviewed the records of 46 patients undergoing revision hip arthroplasty with severe acetabular bone loss. Clinical outcomes were assessed using Harris Hip Score, Western Ontario and McMaster Universities, and Short-Form 12. Mean follow-up was 50 months. All patients had Paprosky type IIc or III acetabular bone deficiency. Major complications included 1 infection, 2 dislocations, and 1 arterial bleeding. Average Harris Hip Score was 78.2. Short-Form 12 scores were within population-based age-matched averages. Western Ontario and McMaster Universities scores were mainly in the 2 lowest disability categories. Porous tantalum shows promising results in revision arthroplasty with severe acetabular bone loss.

Posttraumatic avascular necrosis of the talus.

Avascular necrosis of the talus is one the most challenging problems encountered in posttraumatic reconstruction of the hindfoot. Since the first description of the talus injury in 1608 by Fabricius of Hilden, our knowledge of the talar anatomy, injuries, sequelae, and management has increased significantly. Adequate knowledge of the etiology, the extent of the disease, and the degree of patient symptoms are required to determine optimal treatment.

Augmentation of tibial plateau fractures with Trabecular Metal™: a biomechanical study

BackgroundRestoration and maintenance of the plateau surface are the key points in the treatment of tibial plateau fractures. Any deformity of the articular surface jeopardizes the future of the knee by causing osteoarthritis and axis deviation. The purpose of this study is to evaluate the effect of Trabecular Metal (porous tantalum metal) on stability and strength of fracture repair in the central depression tibial plateau fracture.MethodSix matched pairs of fresh frozen human cadaveric tibias were fractured and randomly assigned to be treated with either the standard of treatment (impacted cancellous bone graft stabilized by two 4.5 mm screws under the comminuted articular surface) or the experimental method (the same screws supporting a 2 cm diameter Trabecular Metal (TM) disc placed under the comminuted articular surface). Each tibia was tested on a MTS machine simulating immediate postoperative load transmission with 500 Newton for 10,000 cycles and then loaded to failure to determine the ultimate strength of the construct.ResultsThe trabecular metal construct showed 40% less caudad displacement of the articular surface (1, 32 ± 0.1 mm vs. 0, 80 ± 0.1 mm) in cyclic loading (p < 0.05). Its mechanical failure occurred at a mean of 3275 N compared to 2650 N for the standard of care construct (p < 0, 05).ConclusionThe current study shows the biomechanical superiority of the trabecular metal construct compared to the current standard of treatment with regards to both its resistance to caudad displacement of the articular surface in cyclic loading and its strength at load to failure.

Improving greater trochanteric reattachment with a novel cable plate system.

Cable-grip systems are commonly used for greater trochanteric reattachment because they have provided the best fixation performance to date, even though they have a rather high complication rate. A novel reattachment system is proposed with the aim of improving fixation stability. It consists of a Y-shaped fixation plate combined with locking screws and superelastic cables to reduce cable loosening and limit greater trochanter movement. The novel system is compared with a commercially available reattachment system in terms of greater trochanter movement and cable tensions under different greater trochanteric abductor application angles. A factorial design of experiments was used including four independent variables: plate system, cable type, abductor application angle, and femur model. The test procedure included 50 cycles of simultaneous application of an abductor force on the greater trochanter and a hip force on the femoral head. The novel plate reduces the movements of a greater trochanter fragment within a single loading cycle up to 26%. Permanent degradation of the fixation (accumulated movement based on 50-cycle testing) is reduced up to 46%. The use of superelastic cables reduces tension loosening up to 24%. However this last improvement did not result in a significant reduction of the grater trochanter movement. The novel plate and cables present advantages over the commercially available greater trochanter reattachment system. The plate reduces movements generated by the hip abductor. The superelastic cables reduce cable loosening during cycling. Both of these positive effects could decrease the risks related to grater trochanter non-union.

Biomechanical analysis of trochanteric fracture fixations using a Y-shaped locking plate.

Objectives: Clinical evidence suggests that the use of Y-shaped locking plates with anterior and lateral locking screws provide improved primary fixation stability over the use of straight locking plates in the treatment of greater trochanter (GT) fractures. However, it remains unclear how the use of cable cerclages, in replacement or addition to the locking screws, would impact the primary fixation stability. Methods: Nine surgical fixations were tested on a dynamic test bench through 27 sawbones experiments. These fixations on the GT and bone shaft (BS) included locking screws alone, cable cerclages alone, or 7 combinations of both. Migrations, defined as the remaining movements of the unloaded GT fragment, were measured for all 9 fixations submitted to dynamic stair climbing cycling after an experimental plan. Results: Under dynamic stair climbing conditions: (1) Y-shaped locking plates fixed by locking screws alone (vs cable cerclages alone) significantly reduced GT migrations, (2) adding cable cerclages to screws provided no significant reduction of migrations, and (3) cable cerclages alone can be used on the BS but is not recommended on the GT. Conclusions: Y-shaped locking plates with anterior and lateral locking screws improved primary stability of GT fractures over fixation with cable cerclages. Cable cerclages provided acceptable primary stability when screw fixations were unachievable but on the BS only.

Fractures of the greater tuberosity of the humerus: a study of associated rotator cuff injury and atrophy

Background This is a retrospective prognostic study on soft tissue injury following isolated greater tuberosity (GT) fractures of the proximal humerus with respect to the relationship between rotator cuff tears and GT displacement. Methods Forty-three patients with isolated GT fractures were recruited and evaluated with a standardized interview and physical examination, quality of life and shoulder function questionnaires (Western Ontario Rotator Cuff Index, SF-12 Version 2, Constant, Quick-Disabilities of the Arm, Shoulder and Hand, Visual Analogue Scale), standard shoulder radiographs and an ultrasound. The main outcome measurements were: incidence of rotator cuff tears and atrophy, biceps pathology and sub-acromial impingement; superior displacement of the GT fragment; and questionnaire scores. Results Mean age was 57 years (31 years to 90 years) with a follow-up of 2.4 years (0.8 years to 6.8 years). In total, 16% had a full rotator cuff tear and 57% showed subacromial impingement on ultrasound. Full rotator cuff tears and supraspinatus fatty atrophy significantly correlated with decreased function and abduction strength. Significant atrophy (>50%) of the supraspinatus and infraspinatus, without a rotator cuff tear, was correlated with the worst function in the presence of a residual displacement of the greater tuberosity at the last-follow-up (7 mm). Conclusions Residual displacement, full rotator cuff tear and muscle atrophy are associated with the worst outcomes. Soft tissue imaging could benefit patients with an unfavourable outcome after a GT fracture to treat soft tissue injury.

Management of a bent femoral intramedullary nail associated with an ipsilateral femoral neck fracture--a case report.

Interlocked intramedullary (IM) nails are the standard treatment for most femoral shaft fractures. In rare instances after femoral nailing, a patient presents with a bent nail as a result of another trauma. Authors have previously described different techniques for the removal and replacement of such bent nails.1–8 However, in the presence of an ipsilateral femoral neck fracture, removal of the nail may be inappropriate. We report a technique for correcting the nail deformity and fixing the shaft fracture without removing the nail, thus minimizing the risk of displacing the femoral neck fracture.

Impact of olecranon fracture malunion: Study on the importance of PUDA (Proximal Ulna Dorsal Angulation).

PURPOSE The Proximal Ulna Dorsal Angulation (PUDA) is part of the proximal ulnas normal anatomy. The importance of restoring ulnar anatomy characteristics precisely after olecranon fracture is not known, however, failure to recreate the PUDA after surgery may result in poorer functional outcomes. The purpose of this study is to evaluate the impact of minimal proximal ulna malunion on elbow ROM and function at least one year after olecranon ORIF. METHOD A retrospective comparative cohort study took place in three level-1 trauma centers. Forty-nine adult volunteers who underwent ORIF for olecranon fracture were included. Patients were separated into two groups according to PUDA malreduction-defined as more than 5° of difference between the fractured and the contralateral elbow. OUTCOME MEASUREMENTS Radiographic ROM measurement, demographic data and quality of life questionnaires were recorded (PREE, MEPS, Q-DASH, SF12, VAS). RESULTS The mean follow up was 3 years and 9 months (1-7 years). There was no difference in terms of outcome, quality of reduction or range of motion between patients treated with plate or tension band. The mean PUDA on the fracture side was different from the normal side (2.20 vs 4.90, p<0.001). Fourteen patients (29%) had PUDA malunion. Those patients had decreased elbow flexion (-7°, p=0.011), extension (-11.2°, p=0.013) and total ROM (-18.6°, p=0.006) as opposed to the control group. Both groups had comparable quality of life questionnaire scores. Alcohol consumption was the only risk factor associated with worse scores. CONCLUSION Incidence of olecranon malunion-as defined by PUDA measurement - was 29% and it was associated with decreased elbow range of motion. Alcohol consumption was correlated with a worse prognosis in our series of patients. Tension band and plate fixation can maintain a good reduction in terms of PUDA and the choice of fixation method does not influence outcome. LEVEL OF EVIDENCE III Therapeutic study.

Anterior locking plate reduces trochanteric fracture migrations during hip extension

BACKGROUND Greater trochanter fractures or osteotomies fixed with lateral plates still present high rates of complications. Unblocked greater trochanter anterior movement during hip extension might be a possible cause of failure. This study aimed to determine, under stair climbing conditions, the biomechanical behaviour of a greater trochanter fragment and the impact of an anterior locking plate on its migration. METHODS Eighteen femurs paired from nine fresh frozen cadaveric specimens were tested on a quasi-dynamic stair climbing cycling test bench. Left and right sides with greater trochanter fractures were randomly fixed either with an antero-lateral locking plate or with a lateral locking plate. Migrations, defined as the remaining movements of the unloaded greater trochanter fragment, were measured for all 18 femurs. FINDINGS During hip extension, multi-directional greater trochanter fragment movements occurred and showed a back-and-forth anterior rotation. The lateral locking plate failed due to greater trochanter fragment rotation around the superior axis and anterior translation. The antero-lateral locking plate significantly reduced greater trochanter anterior migration (-0.9 mm ± 1.6) compared to the lateral locking plate (9.6 mm ± 9.5). INTERPRETATION Hip extension provides a plausible explanation for the high rate of post-operative failures of greater trochanter fixations. An antero-lateral locking plate represents an efficient surgical alternative counteracting the multi-directional greater trochanter movements occurring during hip extension.