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Ballard v. Zimmer, Inc.

United States District Court, N.D. Illinois, Eastern Division

January 7, 2015

ZIMMER, INC., Defendant

For Pamela M Ballard, Plaintiff: Edward John Walsh, Jr., LEAD ATTORNEY, Adam Christopher Kruse, Walsh, Knippen, Pollock & Cetina, Chartered, Wheaton, IL.

For Zimmer, Inc., a corporation, Defendant: Michael John Kanute, LEAD ATTORNEY, Mindy Anne Finnigan, Faegre Baker Daniels LLP, Chicago, IL; Adrienne Busby, PRO HAC VICE, Faegre Baker Daniels, L.l.p., Indianapolis, IN.


REBECCA R. PALLMEYER, United States District Judge.

Plaintiff Pamela Ballard brings this products liability action against Defendant Zimmer, Inc., alleging that her hip replacement had a manufacturing defect, which caused severe injuries to her femur and surrounding muscles. She presented the opinions and testimony of Dana J. Medlin, Ph.D. in an initial report. One day before the court-ordered deadline for dispositive motions, Plaintiff filed a supplemental expert disclosure. The next day, Zimmer moved to exclude all of Dr. Medlin's testimony and opinions [44], arguing that his methodology is unreliable. Zimmer also moved for summary judgment. In response to these two motions, Plaintiff submitted two additional affidavits from Dr. Medlin, presenting new opinions in response to Zimmer's expert report. Zimmer moves to strike those affidavits [68] as untimely and argues alternatively that, even if the court considers them, they are unreliable and should be excluded along with the remainder of Dr. Medlin's testimony.

Currently before the court are Zimmer's motion to strike the two affidavits and its motion to exclude the remaining testimony of Dr. Medlin. The court disagrees with Zimmer that considering the disputed affidavits would be prejudicial and denies the motion to strike. The court, however, cannot conclude on the current record whether the methodology employed in Dr. Medlin's affidavit in response to the motion for summary judgment is reliable and requires a hearing before it will determine whether the affidavit is admissible under Federal Rule of Evidence 702.


Pamela Ballard suffered degenerative arthritis in her hip and underwent hip replacement surgery in 2003. (Pl.'s Resp. to Def.'s Local R. 56.1 Statement [53], hereinafter " Pl.'s Resp. to Def.'s SOF, " ¶ 2.) Her doctor implanted a Zimmer-manufactured VerSys Hip System Femoral Head (" Head") and a VerSys Hip System Beaded Fullcoat Femoral Stem (" Stem"). (Id. ¶ 2.) The outside of the Head is spherical; it replaces the rounded head of the patient's femur, which fits into the hip socket, and the bottom of the Stem attaches to the patient's femur. (Medlin Dep., Ex. A to Pl.'s Resp. to Mot. to Exclude [55-1], hereinafter " Medlin Dep., " 15:25-16:8, 100:17-19.) The Head and the Stem fit together to form a " modular junction." (Mem. of Law in Supp. of Zimmer Inc.'s Mot. for Summ. J. [41], 2.) The interior of the Head is a hollow cone formed in such a way that the cone-shaped Stem will fit inside it. (Medlin Dep. at 66:13-67:3.) As Dr. Medlin explained in his deposition, the Head sits on top of the Stem and the two are pressed together so that friction holds the components together: how tightly the two pieces fit together is referred to as the " press-fit." (Id. at 65:19-25.) The press-fit is based on how similar the dimensions of the Head and Stem are: there will be a better fit and a more even distribution of weight on the junction if the diameter of the Stem matches the diameter of the interior of the Head, and if the angles of Stem and interior of the Head are the same, so that the two pieces fit closely together. A better press-fit leads to a more stable hip, but when inadequate, microscopic movement (" micro-motion") of the Stem inside the Head can result. (Dana J. Medlin Investigative Report, Ex. I to Zimmer Inc.'s Statement of Undisputed Facts in Supp. of Its Mot. for Summ. J. [43-9], hereinafter " Medlin Rep., " 3.) Some amount of micro-motion is inevitable with modular junction implants (Medlin Dep. at 133:12-134:13), but severe micro-motion can cause the Stem to rock inside the Head with enough force that, over time, small amounts of metal wear off, potentially causing corrosion. (Medlin Rep. at 3; Medlin Dep. at 115:12-117:5.)

After her surgery, Plaintiff successfully completed physical therapy, and for several years was able to exercise regularly, travel, and hike. (Pl.'s Resp. to Def.'s SOF ¶ ¶ 5-7.) In October 2009, Plaintiff's hip dislocated. (Pl.'s Resp. to Def.'s SOF ¶ 8.) After a second dislocation in December 2009, her doctor decided to remove part of the implanted prosthetic. (Pl.'s Resp. to Def.'s SOF ¶ ¶ 10, 11.) It is undisputed that removing the Stem would have risked extensive damage to Mrs. Ballard, including possible bone death; the Stem, therefore, remains implanted in Plaintiff's body and is unavailable for inspection. (Id. ¶ 12.) Plaintiff brought this suit, alleging that her hip implant suffered from a manufacturing defect that caused her injuries. ( See Compl., Ex. A to Notice of Removal [1-1].)

I. Plaintiff's expert's initial report and deposition

Plaintiff's expert disclosures were due by April 15, 2013 (Jan. 30, 2013 Minute Entry [33]), and on that day, Plaintiff disclosed the report of Dana J. Medlin, Ph.D. Dr. Medlin is a senior consultant at Engineering Systems, Inc., a professional engineering consulting firm. (Pl.'s Resp. to Def.'s SOF ¶ 53.) He has over 20 years of experience in metallurgical, materials, and biomedical engineering--including five years at Zimmer in its materials research group. (Id.) While at Zimmer he focused on metals research, developing new materials to be used in Zimmer's various implants. (Medlin Dep. at 29:12-15.) He also worked on a hip implant project and some knee projects. (Id. at 31:10-15.) Most of Dr. Medlin's experience is with hips and knees, but he has knowledge of the materials that are used to develop implants for other parts of the body, as well. (Id. at 31:25-32:6.)

Dr. Medlin concluded, based on his examination of the explanted Head, that there was evidence that the Stem rocked back and forth inside the Head at a microscopic level, which caused the metal of the inside of the Head to wear off (" fretting") and resulted in corrosion damage to the interior of the Head. (Medlin Rep. at 3, 8.) To reach his conclusion, Dr. Medlin conducted a visual examination of the Head, using various levels of magnification. (Id. at 3-7.) First, he noted that the interior of the Head (where the Stem fits in) had " two large thumbnail shaped scars on diametrically opposed sides of the internal taper, " indicating, to him, that the Stem rocked back and forth inside the Head causing wear to the interior of the Head. (Id. at 3.) He also observed that the scars were located closer to the opening at the bottom of the Head, and from that observation, he determined that " the proximal [deeper] region of the bore [Head] had better fixation on the trunnion [Stem] than the distal region [towards the opening]." (Id. at 4.) This discrepancy in fixation " caused micro-motion (rocking) and fretting at the opening of the bore." (Id.) Dr. Medlin next inspected the interior of the Head using a scanning electron microscope at various levels of magnification to examine the damage to the Head. (Id. at 5.) This examination showed evidence of corrosion, which Dr. Medlin opined was due to metal ions released into Plaintiff's body from the metal that had worn off the interior of the Head. (Id. at 7.) After identifying micro-motion as the source of the damage to the Head, Dr. Medlin concluded that the cause of the micro-motion itself was a " mismatch in the taper angle and/or diameter between the" Head and Stem. (Id. at 8.) That is, the two components were not close enough in their respective dimensions, which caused the Stem to rock inside the Head and cause wear to the metal. (Id. at 8.) Dr. Medlin proposed two possible explanations for the cause of the mismatch between the dimensions of the Head and Stem: One possibility is that the Head and Stem's diameters were both within Zimmer's design specifications, but at the extreme ends of Zimmer's permissible ranges for the dimensions: " [F]or example matching a [Stem] at the smallest diameter tolerance to a [Head] with the largest diameter tolerance may develop in a micro-motion condition that can result in fretting wear and corrosion." (Id. at 7.) The other possibility is that, because " [o]nly 14 of the 100 heads in this lot were inspected" for the diameter dimensions and taper angle, there was the potential for manufacturing error which " may leave some of these components outside the required tolerance range, " that is, outside of Zimmer's specifications. (Id. at 8.) For example, even if the Stem was within specification, the Head may have been outside of the required specifications, creating a mismatch between the Stem and Head.

At his deposition, on May 8, 2013, Dr. Medlin clarified that he did not take any measurements of the inside of the Head because he did not have the correct equipment. (Medlin Dep. at 50:19.) He also opined that, given the significant amount of damage to the interior of the Head, any measurements taken of the explanted Head would not reliably gauge the pre-implantation measurements. (Medlin Dep. at 56:15-19.)

II. Defendant's expert

Defendant's expert disclosures were due May 20, 2013, and Defendant disclosed the report of Dr. Steven Kurtz.[2] (Zimmer Inc.'s Mem. in Supp. of Mot. to Strike Medlin Affs. [69], hereinafter " Def.'s Mem. in Supp. of Mot. to Strike., " 1.) Dr. Kurtz has a Ph.D. in Mechanical Engineering from Cornell University and is the Director of the Biomedical Engineering practice at Exponent, Inc. an engineering and scientific consulting firm. (Zimmer's SOF ¶ 41.) He is also the Director of the Implant Research Center at Drexel University's School of Biomedical Engineering, Science, and Health Systems. (Id.) Dr. Kurtz performed a visual examination similar to the one performed by Dr. Medlin, including basic visual observation and microscopy, but also used a tool called a Talyrond 585 to measure the radius of the inside of the explanted Head. (Steven M. Kurtz Expert Report, Ex. F to Zimmer Inc.'s Statement of Undisputed Facts in Supp. of Its Mot. for Summ. J. [43-6], hereinafter " Kurtz Rep., " 11.) Using the Talyrond, he measured the radius of the explanted Head at six different locations along its vertical axis, at 1.9 millimeter intervals. (Id.) When measuring the radius, Dr. Kurtz excluded the sections of the Head that were most damaged. (Id.) The Talyrond fitted a circle to the remaining sections of the Head and measured the radius of the best-fit circle. (Id.) According to Dr. Kurtz, this is a reliable method for measuring the pre-implantation dimensions of the Head. (Kurtz Dep., Ex. A to Pl.'s Resp. to Def.'s Mot. to Strike [74-1], hereinafter " Kurtz Dep., " 139:5-18, 156:3-21.) He took his six radii measurements and plotted them according to their vertical height to recreate the cone shape of the interior of the Head and plotted a ...

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