Appeal from the Circuit Court of Cook County Honorable Deborah Mary Dooling and Aaron Jaffe, Judges Presiding
 The opinion of the court was delivered by: Justice McNULTY
 In August 1994 Richard Mele sued Howmedica, Inc., the manufacturer of a medical device a surgeon implanted into plaintiff. The trial court denied plaintiff's motion for certification of a class of all patients into whom surgeons in Illinois implanted similar devices. A jury found that plaintiff did not have notice of wrongful causation for his injury until September 1992. The jury also found that Howmedica's unreasonably dangerous medical device caused plaintiff's injury. The court entered judgment on the jury's verdict awarding plaintiff $400,000 in damages. Defendant appeals and plaintiff cross-appeals from denial of the motion to permit the lawsuit to proceed as a class action.
 Plaintiff had severe arthritis in his right hip. He went to Dr. Mitchell Sheinkop, an orthopedic surgeon, in May 1991. Dr. Sheinkop recommended a total replacement of the hip with artificial components. Plaintiff agreed. Dr. Sheinkop performed the surgery on May 28, 1991.
 To gain access to the hip Dr. Sheinkop needed to cut through the femur, the bone that extends from the hip to the knee. The femur has a nearly spherical head which fits into the acetabular cup of the hip; near the femur's head lies a large protuberance called the trochanter, where several muscles attach to the bone. Dr. Sheinkop performed a trochanteric osteotomy on plaintiff. That is, he cut through the bone and pulled out the top part, including the trochanter.
 Dr. Sheinkop then cemented an artificial stem into the marrow canal of the femur. The artificial stem connected to an artificial nearly spherical head of the femur, designed to move smoothly in an artificial acetabular cup. Dr. Sheinkop implanted an artificial acetabular cup, with a smooth polyethylene lining, into plaintiff's hip, to complete the artificial joint.
 After inserting the artificial pieces, Dr. Sheinkop reattached the top part of the femur, including the trochanter, to the portion of the femur that remained in place during the surgery. For the artificial hip to perform properly, the femur must heal, with the top part of the femur realigning with the body of the femur. When Dr. Sheinkop put the top of the femur back in place, he secured it to the body of the femur with a Dall-Miles trochanter cable grip system (D-M system) manufactured by defendant.
 On the day of surgery, shortly after the operation, Dr. Sheinkop discovered a dislocation of the hip. About 7% of patients experience similar dislocations following hip replacement surgery. Dr. Sheinkop and his assistants, using accepted techniques, manipulated the hip back into place.
 At follow-up visits in February and September 1992, plaintiff complained to Dr. Sheinkop of pain in the hip. Dr. Sheinkop took X rays during both visits. According to the medical record for September 18, 1992, Dr. Sheinkop then "introduced the thought of removing the Dall-Miles cable system" to alleviate the pain. In a second surgery performed on January 28, 1993, Dr. Sheinkop removed the D-M system.
 In September 1997 plaintiff consulted another doctor about increasing pain in his thigh. New X rays showed that plaintiff had suffered endosteal lysis, which is a form of severe bone loss. The doctor recommended revision surgery to replace several elements of the artificial hip. Dr. Aaron Rosenberg performed the revision surgery in November 1997. Plaintiff recovered well from the surgery.
 The complaint filed in August 1994 included a class action count, in which plaintiff sought to represent all persons into whom surgeons implanted the D-M system in the course of hip surgeries performed in Illinois. Plaintiff listed several questions allegedly common to claims of all class members, including the question of whether the D-M system had a design defect rendering defendant strictly liable in tort and whether defendant negligently designed the D-M system. Plaintiff also requested class certification with the class action limited to "one or more of the common questions" listed.
 Plaintiff supported his motion for class certification with an article reporting on a study of the D-M system. Silverton, "Complications of a Cable Grip System," 11 J. Arthroplasty 400 (1996). Dr. Silverton reported that, at the one hospital studied, five surgeons used the D-M system in 68 surgeries performed between January 1990 and July 1992. Eight of the patients had large deposits of metal debris near the joint of the femur with the hip. 11 J. Arthroplasty at 401. "Bone destruction or osteolysis around the cable in the area of the lesser trochanter was seen in seven patients (10%)." 11 J. Arthroplasty at 401. Five of the patients needed reoperations due to painful cables and fragmentation. 11 J. Arthroplasty at 401. As a result of the study, the hospital decided not to use the D-M system for routine trochanteric osteotomies. 11 J. Arthroplasty at 404.
 Plaintiff found two other patients who filed lawsuits against defendant alleging defective design of the D-M system.
 After argument on the motion for class certification, the court said:
 "[B]ifurcation, as I understand it, at least deals with establishing liability first and then going on to damages.
 And I don't think that's what we're doing in this particular case. I have trouble certifying the class for a number of reasons.
 It's a medical device. And I went through the transcript, and as I understand it, there's not great numerosity here.
 [Dr. Silverton] mentions a doctor in Boston who's had excellent results. And so Silverton says I can't understand why we had these results.
 I just can't say I have numerosity because these people have the device implanted in them. ***
 It's not a tort liability like an airplane crash where *** it arises out of one occurrence.
 *** [I]f I would certify the class, it would result in piecemeal litigation with troubling issues of causation and damage left unresolved.
 It seems to me that too many details would be left unresolved, and complex individual trials would need to be adjudicated as well.
 *** I don't think that (A) you established numerosity.
 You talk about predominance, and we talk about adequacy of representation. I don't think that he's a proper class representative because these are tort cases, and they are very different than the mass disaster torts ***.
 I think they are completely different. I think it's a products case. And I think that looking down the line, I think there are too many individual legal issues that really predominate."
 Plaintiff moved for clarification of the basis for denial of class certification. The court denied the motion. Plaintiff then moved for an order pursuant to Supreme Court Rule 308 (155 Ill. 2d R. 308) to permit immediate appellate review of the denial of class certification. At the hearing the court responded:
 "[T]here are individual issues in this thing that make it very difficult for you to have class certification. ***
 I've read the cases. When you have product liability cases that concern medical devices I think that the courts are hesitant to move in that area. ***And for that reason and for a multitude of other reasons, which have been argued for many many hours now, I am going to deny the [Rule] 308 request."
 After plaintiff's second deposition, defendant moved for summary judgment, arguing that the deposition testimony showed that by February 1992 plaintiff had sufficient notice of wrongful causation to trigger the statute of limitations period. The defendant argued that the filing of the complaint in August 1994 came too late. The trial court found material issues of fact concerning the time plaintiff discovered wrongful causation for his injury. Accordingly the court denied the motion for summary judgment.
 Before trial plaintiff moved to exclude evidence of "the expectation of injury by anyone other than [an] implantee patient; *** the comparative superiority of the Dall-Miles cable over other fixation devices; *** the fact that there was a need for a cable in view of problems with earlier fixation devices; *** the fact that other fixation devices or other cable can abrade bone, fray or fragment; *** [and] a risk versus benefit test."
 Plaintiff sought to prove that the D-M system was designed defectively in that it did not perform as safely as an ordinary implantee would expect. He argued that the evidence he sought to exclude bore no relevance to the case, because the evidence would rebut only a case in which a plaintiff tried to show that another design could achieve similar benefits with less risk. Defendant argued that surgeons who implanted the system were its consumers for purposes of determining whether the device met the expectations of ordinary consumers. In the alternative defendant sought to show that the benefits of the product outweighed its risks.
 "[I]n this case, the plaintiffs have decided to bring their action on strict liability in tort based only on the consumer user contemplation test.
 So that would for the court set up the parameters of what is relevant. I did not see a case where that was the claim and solely that being the consumer user approach where that was used by the plaintiff that the defense could then *** rebut that claim or put on a defense of the danger utility or risk benefit when the sole claim was the consumer user expectation test.
 So the court is going to judge the relevance of what evidence goes in *** based on the claim of the plaintiff. ***
 *** And the risk benefit analysis is out given the pleadings by the plaintiff."
 At trial plaintiff testified that when he complained of pain nine months after the initial surgery, on February 28, 1992, Dr. Sheinkop told him that such pain was a "very normal" part of recovery, and it may persist for 18 months after a successful surgery. The pain persisted into September, when plaintiff next visited Dr. Sheinkop. Plaintiff testified that Dr. Sheinkop then suggested that the D-M system might be the cause of the pain and that plaintiff might want the system removed. Contrary to his trial testimony, plaintiff at his second deposition had testified that he learned in February 1992 that the D-M system caused the pain. At trial plaintiff explained that he confused the dates in his testimony at the second deposition. Prior to the September 1992 visit with Dr. Sheinkop, he had never heard of the D-M system, and he had no idea Dr. Sheinkop had placed such a device in him. Plaintiff testified that he was very surprised to learn about the system and to learn that it might be the cause of his pain.
 According to plaintiff, the first surgery in May 1991 relieved the pain from arthritis that led him to choose hip replacement surgery. But new pains began around February 1992. Plaintiff described the pain and disability he suffered from that time until spring of 1998, when he completed his recovery from his third hip surgery, the revision operation Dr. Rosenberg performed. The surgical removal of the D-M system in January 1993 did not alleviate the pain.
 On cross-examination plaintiff admitted that shortly after February 1992 he telephoned a friend of his neighbor who worked as an attorney. He discussed with the attorney possible legal liability for the pain he continued to suffer. But plaintiff did not then meet with or retain an attorney.
 Dr. Sheinkop testified that as a general practice he discussed with each patient the benefits and risks associated with the surgery proposed for the patient. He usually would not discuss the possibility of dislocation with hip replacement patients. He would not describe the trochanteric osteotomy, as part of the hip replacement, to his patients. And he usually would not mention the device he used to reattach the parts of the femur following a trochanteric osteotomy. Dr. Sheinkop did not recall giving any special warnings to plaintiff.
 Dr. Sheinkop described the first surgery and his use of the D-M system. He secured the top of the femur, including the trochanter, to the body of the femur by drilling a hole in the trochanter and passing the cable of the D-M system through the hole. He cut the end of the cable with a cutter that was also part of the D-M system. The cable, attached to the grip, then held the two parts of the bone in place.
 The cable consisted of a number of wires wound together. The wound wires gave the cable a rougher surface than an individual monofilament wire. Dr. Sheinkop believed that when plaintiff walked the cable moved very slightly back and forth through the bone. Dr. Sheinkop characterized this effect as micromotion that acted like a saw against the bone. The abrasion of the cable separated small particles of the bone near the hole from the rest of the bone. X rays of plaintiff's femur showed expansion of the hole for the cable. In September 1992 Dr. Sheinkop noted in plaintiff's medical record that the X ray showed bone loss in connection with the D-M system.
 In general Dr. Sheinkop would discuss the X rays with the patient the same day he took them. He admitted that the X ray he took in February 1992 showed expansion of the hole drilled for the cable, probably due to the sawing effect of the cable against the bone. He did not specifically ...