Wearing arm splint affects driving ability

Study finds that arm splints make it more difficult to control a vehicle

An arm splint can negatively affect a driver’s ability to control a vehicle—especially if that splint is applied to the left upper extremity, according to  the results of a study on driving performance at the 2009 annual meeting of the American Society for Surgery of the Hand.

The research team filmed and interviewed 30 healthy police officers-in-training who were tested on a cone-marked driving course in a randomized, balanced cross-over study. Each cadet made control runs with no splints as well as runs while wearing various types of fiberglass splints, including long arm thumb spica and short arm splints on both left and right sides. The order of the runs was randomized for each participant to minimize learning effects.

The participants were tested on the standardized driving course where they had been training for several weeks prior to the study. The course has an established scoring system, and is normally used to certify the driving skills of emergency personnel.

Scores were based on the time it took to complete the course; a penalty of 5 seconds was assessed each time the driver hit a cone. A participant passed the course if he or she completed the run in less than 230 seconds with fewer than 4 cones hit.

“These cadets are trained to drive in a very specific fashion,” explained Donald H. Lee, MD, one of the study’s authors. “They are taught to use the shuffle steering method. When they’re backing up, they’re taught to turn to the right and look out the rear window.”

Left side splints are worse
The research team found that left long arm thumb spica splints were the most detrimental to performance, with participants’ cone-penalized time increasing on average by 22.2 seconds (p < 0.001) compared to controls. Left short arm splints were the second most detrimental, with average increases of 16.2 seconds (p = 0.007).

“We were not expecting that,” said Dr. Chong. “We were expecting that people with right-hand dominance would do worse if the right upper extremity was immobilized.”

The researchers found similar trends in the number of cones knocked down and, although the data did not approach significance, left arm splints continued to increase cone-penalized time even when the analysis was limited to portions of the course that did not involve backing up.

The researchers also asked each cadet to rate the perceived difficulty and safety driving the course for each splint used. Participants in the study consistently rated the left long arm thumb spica splint with the highest perceived difficulty and the lowest perceived safety.

“Backing up seems to be quite difficult with a left arm cast, because of the way American cars are designed, with the driver’s seat on the left side,” said Dr. Chong. “When you back up while looking out the back window, you have to use the left arm to steer. I think that played a large part in why people didn’t do well with a left-arm splint.”

What to tell patients?

 
“This is a best-case scenario,” said Dr. Lee. “These were trained drivers who had no pain. They didn’t have a fracture or an injury. They had been driving on this course for several weeks. Nonetheless, they had difficulty with immobilization. If we extended the results to the general population, and to drivers who may be in pain as well as immobilized, we can assume that they would perform worse.”

Given that, what advice is reasonable for orthopaedic surgeons to offer their patients who may wish to climb behind the wheel of an automobile?

“This test wasn’t about liability issues, which are always a concern,” explained Dr. Lee. “Driving with a splint does impair mobility. My response to patients is that, as long as they’re not going to cause further damage to an injury, they’re driving at their own risk. Our job is not to determine whether they have the capability of driving. I think they eventually have to decide on their own or at least know their own limitations.” 

The study co-authors include: Elizabeth A. Koehler, MS; Yu Shyr, MD; Douglas R. Weikert, MD; and Jeffry T. Watson, MD.

AAOS Now
January 2010 Issue
http://www.aaos.org/news/aaosnow/jan10/clinical5.asp

Thanks,

JTM, MD
 

Minimally invasive TKA shows little benefit in outcomes

So an established patient comes into the office to see me for some knee pain.  He has been researching knee arthritis on the internet and finds a web site that promotes "minimally invasive " knee replacements.  He is thinking about going to Chicago to have his total knee done.  I wish him well.

"Minimally invasive" is a very popular term and seems to be more marketing shtick than reality.  There may be some role for it in certain procedures like rotator cuff repair, but the benefits are questionable when analyzing the long term benefits versus complications for joint replacements.  The is not much of an advantage when doing a total knee replacement to making a small incision if to get the knee components into the patient's body the surgeon must stretch the heck out of the soft tissues.  The short term benefits of a questionably quicker recovery must be compared to the long term problems related to component malpositioning due to limited surgical exposure.  Below is an article from the AAOS news.  (My thoughts, JTM, MD)

Postoperative strength, functional recovery similar to standard approach

A prospective, randomized, double-blinded study comparing postoperative strength and functional recovery after minimally invasive or standard total knee arthroplasty (TKA) showed limited benefits for the minimally invasive (MIS) approach—and those benefits had disappeared by 6 weeks after surgery.

“The cited advantages of minimally invasive TKA are well known,” said presenter Bryan J. Nestor, MD. “Most studies to date, however, have been either retrospective or at best prospective comparisons with matched controls and as such fail to control for the influence of patient expectations, placebo effect, or selection bias. Only two studies have measured quantitative differences in quadriceps muscle strength.”

The study involved 27 patients (mean age 66.7 years; 18 females) who were candidates for bilateral TKA. Each patient was randomized to receive a minimally invasive midvastus approach on one knee (Fig. 1) and a standard quad-splitting approach on the other. Skin incisions were of equal length so that both patients and investigators were blinded as to the approach used. All other aspects of the surgery were identical, including the implant design (cemented posterior stabilized design), treatment of the patella (resurfaced), anesthesia (spinal epidural with a femoral nerve block), and postsurgical standardized clinical pathways for physical therapy and pain management.

Fig. 1 Intraoperative photo of MIS TKA. Courtesy of Bryan J. Nestor, MD

Quadriceps strength testing
Isometric strength testing was measured with the knee in 30 degrees and 60 degrees of flexion, with peak torques reported for each of three trials. Isokinetic strength was performed at velocities of 60 degrees/second and 180 degrees/second through a motion arc of 0 degrees–90 degrees, and peak torques were reported for each trial.

Quadriceps strength testing was performed before surgery as well as at 3, 6, and 12 weeks after surgery. “At 3 weeks after surgery, we observed a significant increase (p < .05) in isokinetic extensor peak torque and isometric strength in the minimally invasive midvastus group,” reported Dr. Nestor. “Likewise, with the isokinetic data, at 60 degrees/second, the difference was significant at 3 weeks after surgery, again favoring the MIS group.”

The early differences in strength did not last, however; by 3 months after surgery, patients in both groups had returned to presurgery levels of quadriceps strength. 

Functional recovery
Researchers used an instrumented walkway to conduct a gait analysis; stride length, single hip stance time, and double limb stance time were also measured and average data from three trials were used for analysis.  

They found no differences between the standard and minimally invasive knees at any point (3, 6, and 12 weeks after surgery). 

“Based on a visual analog scale, patients reported no difference in pain between the two approaches at any point,” said Dr. Nestor. “The only significant difference in range of motion was on postoperative day 3, again favoring the minimally invasive approach. When we asked patients about which knee had less swelling, stiffness, or weakness, we found a patient preference for the MIS knee at 3 weeks, but that difference had disappeared by 6 weeks, which is when most patients return for follow-up. By 12 weeks, most patients reported that both knees felt the same.”

Radiograph analysis
A radiographic analysis was performed at the 6-week follow-up to assess alignment. Researchers found no significant differences in radiographic outliers between the MIS and standard approach knees, although two knees in the MIS group had tibial malalignment in the coronal plane, compared to no knees in the standard-approach group.

“Unlike previous studies, the cited advantages of MIS TKA—improved early range of motion and less pain—were not observed in this study. Our results do concur with a recent multicenter randomized clinical trial that compared the MIS midvastus and standard approaches and showed no clinical difference. Although we saw modest improvement in quadriceps strength, as well as patient preference for the MIS midvastus approach at 3 weeks, that effect was lost at 6 weeks,” summarized Dr. Nestor.

“At least one study has raised concerns about increased component malalignment,” he continued, “and we did observe tibial malalignment in the MIS group and not in the standard group, although this was not statistically signficiant. 

“In conclusion, the MIS mid-vastus approach offers limited, if any, benefits compared to a standard TKA approach, and the potential risk of tibial component malalignment is cause for concern.”

AAOS Now
January 2010 Issue
http://www.aaos.org/news/aaosnow/jan10/clinical9.asp

Thanks,

JTM, MD