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The Bone & Joint Journal
Vol. 102-B, Issue 7 Supple B | Pages 20 - 26
1 Jul 2020
Romero J Wach A Silberberg S Chiu Y Westrich G Wright TM Padgett DE

Aims

This combined clinical and in vitro study aimed to determine the incidence of liner malseating in modular dual mobility (MDM) constructs in primary total hip arthroplasties (THAs) from a large volume arthroplasty centre, and determine whether malseating increases the potential for fretting and corrosion at the modular metal interface in malseated MDM constructs using a simulated corrosion chamber.

Methods

For the clinical arm of the study, observers independently reviewed postoperative radiographs of 551 primary THAs using MDM constructs from a single manufacturer over a three-year period, to identify the incidence of MDM liner-shell malseating. Multivariable logistic regression analysis was performed to identify risk factors including age, sex, body mass index (BMI), cup design, cup size, and the MDM case volume of the surgeon. For the in vitro arm, six pristine MDM implants with cobalt-chrome liners were tested in a simulated corrosion chamber. Three were well-seated and three were malseated with 6° of canting. The liner-shell couples underwent cyclic loading of increasing magnitudes. Fretting current was measured throughout testing and the onset of fretting load was determined by analyzing the increase in average current.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_12 | Pages 2 - 2
1 Oct 2019
Padgett DE Romero J Wach A Wright TM
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Introduction

Enhanced stability using dual mobility has been demonstrated but concerns about potential for corrosion in modular versions have been raised. Case reports of corrosion with malseated inserts have heightened concerns over this modularity. Some have claimed that malseating is rare, the true frequency is unknown. The purpose of our investigation was to determine the incidence of liner malseating in dual mobility implants at our institution.

Methods

567 hips had primary modular dual mobility hip replacements (Biomet or Stryker) between 2016 and 2018. Post-operative radiographs were reviewed independently by two reviewers to identify malseating. Liners were considered malseated if there was a noticeable gap between the metal liner and acetabular shell(figure 1). All liners deemed to be malseated were independently assessed by 3 separate reviewers for confirmation.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_IV | Pages 396 - 396
1 Apr 2004
Boldt J Romero J Hodler J Zanetti M Drobny T Munzinger U
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The purpose of this study was to analyse a potential correlation of arthrofibrosis (AF) and femoral rotational mal-alignment in total knee arthroplasty (TKA). We hypothesized an increased internal mal-rotation of the femoral component leading to unphysiological kinematic motion of the arthroplastic knee joint. These repetitive microtrauma may then induce increased synovial hyperplasia leading to arthrofibrosis. Arthrofibrosis is an ill-defined entity that results in unsatisfactory outcome following TKA. Biological and mechanical factors have been suggested as etiology, but specific causes have not been identified.

Methods: From a cohort of 3058 mobile bearing TKA 44 (1.4%) cases were diagnosed with arthrofibrosis, of which 38 (86%) cases underwent clinical examination and CT investigation to determine femoral component rotation taking the transepicondylar (TEA) axis as reference point. A control group with 38 well functioning TKA was compared.

Results: Increased internal mal-rotation of the femoral component of 5.0° in the AF group (reference to the TEA) was highly significant (p < 0.001) ranging from 10°IR to 1°ER compared with the control group (0.0° parallel to TEA, 4°IR to 5°ER). Men younger than average for index TKA in this center with a decreased BMI, previous knee surgery (particularly correcting osteoto-mies), poliomyelitis, and OA had an increased risk of developing arthrofibrosis. PCL retaining or sacrificing, patella resurfacing or retaining had no increased prevalence for AF. Rheumatoid patients had a decreased risk of developing arthrofibrosis .

Conclusion: The correlation of AF to femoral component internal mal-rotation was statistically significant (p < 0.001). These results confirm that unphysiological kinematics in TKA appear to be a major etiopathological factor for arthrofibrosis (AF). In this study femoral component internal mal-rotation has shown to be a significant risk factor in the development of arthrofibrosis. We, therefore, recommend consideration of early CT evaluation in cases with AF and, when internally mal-rotated, revision of the femoral component.

This study has been cleared by the Ethical Committee, University of Zurich, Switzerland.


The Journal of Bone & Joint Surgery British Volume
Vol. 85-B, Issue 8 | Pages 1141 - 1145
1 Nov 2003
Romero J Gerber C

Spinal accessory nerve palsy leads to painful disability of the shoulder, carrying an uncertain prognosis. We reviewed the long-term outcome in 16 patients who were treated for pain, weakness of active elevation and asymmetry of the shoulder and the neck due to chronic paralysis of the trapezius muscle, as a result of nerve palsy. Of four patients who were treated conservatively, none regained satisfactory function, although two became pain-free. The other 12 patients were treated operatively with transfer of the levator scapulae to the acromion and the rhomboid muscles to the infraspinatus fossa (the Eden-Lange procedure). At a mean follow-up of 32 years, the clinical outcome of the operatively treated patients was excellent in nine, fair in two, and poor in one patient, as determined by the Constant score. Pain was adequately relieved in 11 and overhead function was restored in nine patients. Pre-operative electromyography had been carried out in four patients. In two, who eventually had a poor outcome, a concomitant long thoracic and dorsal scapular nerve lesion had been present.

The Eden-Lange procedure gives very satisfactory long-term results for the treatment of isolated paralysis of trapezius. In the presence of an additional serratus anterior palsy or weak rhomboid muscles, the procedure is less successful in restoring shoulder function.