Research

Updated: November 28, 1999

This page of eRadius is devoted to listing research presentations from meetings around the world. We are looking for Corresponding Editors for North America (AAOS, ORS), Japan, India, and Australia. We need one for SICOT. If you are interested in volunteering or if you know of proceedings that are not listed, please contact the Webmaster.

Note: All comments are by David Nelson, MD, unless otherwise indicated.

Prediction of Instability of Fractures of the Distal Radius
Paul J. MacKenney, FRCS; Margaret M. McQueen, MD; Rob Elton, PhD

Edinburgh Orthopaedic Trauma Unit, Edinburgh, Scotland

Purpose: To produce a method of accurately predicting instability of distal radius fractures on the day of injury which is easily applicable in the clinical situation.

Methods: During a five-and-one-half year period, data were recorded prospectively on 4025 patients with distal radial fracture. The items of information included demographic data, mode of injury, the patient's level of function, and radiological data. The latter included: fracture classification (AO and Frykman); the degree of fracture comminution; measurement of dorsal angulation, radial shift and ulnar variance at presentation, post manipulation, one week, and six weeks after injury; carpal alignment at union. Using the position of the fracture at one and six weeks and the alignment of the carpus as outcome measures, statistical analysis of the data was performed to identify factors of independent significance in the prediction of early instability, late instability, and carpal malalignment respectively. Each factor was analysed using the Mann-Whitney or chi- squared test, and significant factors used in multiple logistic regression analysis. Predictive equations were then derived from the multiple logistic regression.

Results: Factors predictive of fracture instability were seen to vary depending on the position of the fracture at presentation (displaced with more than 10 degrees of dorsal angulation or minimally displaced with less than 10 degrees of dorsal angulation). There were also differences between factors predictive of early and late instability. The most highly significant prognostic factor was the age of the patient (p<0.001), and this applied to all sets of data analysed. Comminution was also important, though to a lesser degree. The dorsal angulation of the fracture at presentation was only of prognostic significance in fractures with minimal displacement at presentation, whereas the ulnar variance was significant in all fractures. Surprisingly, independence in the activities of daily living was of value in predicting late instability in displaced fractures. The sex of the patient, mode of injury, the radial shift at presentation, and Frykman classification was of no prognostic value following multiple logistic regression. In the prediction of carpal malalignment the patient's age and level of function, fracture comminution, AO and Frykman classifications, and the dorsal angulation of the fracture at presentation were all of significance. From the data analysed it was possible to construct an equation to predict the percentage chance of instability after distal radius fracture. The following example is for the probability of early instability in a displaced fracture at presentation:

An example can be given as follows. A 75-year-old lady sustains a distal radial fracture after slipping on ice. She is normally independent and active. Initial dorsal angle is 17 degrees and ulnar variance is 3 mm with dorsal comminution. This patient therefore has a fracture which is displaced at presentation. To calculate the probability of displacement at one week, the formula is used as above. The score is -0.14. Using the probability formula, this patient has an 82% chance of the fracture being unstable at one week.

Discussion and conclusions: Previously it has been demonstrated that the ulnar variance, dorsal angulation, and age of the patient were all factors related to the anatomical outcome following distal radial fracture. We have shown that the significance of these factors depends on the position of the fracture at presentation, and whether one is trying to predict early or late instability. We have shown that the age of the patient is by far the most important factor in assessing the instability of a fracture. It is hoped that refinement of the predictive equations will produce a user-friendly and reliable method of assessing the distal radial fracture at presentation. The value of such a system cannot be underestimated: unnecessary manipulations can be avoided in patients with fractures that require operative fixation, and these patients will be able to have definitive treatment at presentation. In addition, this rationalisation of the treatment protocol is likely to be of economic benefit.

Webmaster's Comments: This is a very important paper and I think that this work will get a lot of attention once it is published. In some ways, it represents a Holy Grail of distal radius fracture management: predicting in the ER which patients will collapse and therefore may need prophylactic fixation of some type, rather than waiting until the collapse happens and then playing catchup, or worse, an osteotomy. (As Jesse Jupiter has phrased it once to me, a Darrach procedure is not fracture aftercare; the implication is that proper fracture care will avoid the salvage procedures down the line.)

The paper only presented one equation, which was the probability of early instability, although that was not clear from the abstract in the program. This was clearer after I talked to the authors after the presentation. During the presentation, they gave a different equation, the probability of late instability:

Dr. McQueen told me that they have four equations based on their dataset. The third one predicts carpal malalignment. She did not mention what the fourth equation represented.

Before you complain, "But I don't have time to do an exponential calculation at 2 am in the ER!", the authors have worked out tables that do all the calculations for you. These could be posted in the ER or reduced and carried in a pocket. Other more convenient means are also underway.

There are a number of surprises in the results of the study. One: the best predictor of late instability is age. I believe that we all have felt that this was a factor, but this is the first study to document (rather than just opine) that this is the most important factor. Two: dorsal angle is not a good predictor. I discussed this with Dr. McQueen (who incidentally is on the Board of Editors of eRadius), who clairfied that, although it was a predictor, it was not an independant predictor and therefore did not make it into the equation. I asked if angle was not more readily measured than degree of comminution (a problem with other attempts at prediction), and learned that communution was rated as either present or absent, not graded, which simplified the matter. Three: mode of injury was not of prognostic significance. I usually feel that high velocity injuries are more unstable; it could be that the dataset did not have enough of these injuries to reflect this contribution. (I await the manuscript, or possibly the authors will respond.) Four: dorsal angulation was of value only with minimally displaced fractures. I would like to know if this means that minimally displaced fractures were predictive of stability, but more displaced fractures were not predictive. This was not clear either from the abstract or presentation.

Criticisms aside, this is a very important work and one that will be a benchmark for future studies. Most questions will probably be answered in the manuscript. Congratulations to the authors (and apologies if I have misunderstood or misrepresented any of your work. I was writing madly in the dark during the presentation, and only remembered a limited number of questions when we spoke.)

There were other good presentations at the OTA, which will be posted as time permits.

Comparison of Structural and Nonstructural Bone Graft for Distal Radius Osteotomy

Celine Roberge, MD, David Ring, MD, and Jesse Jupiter, MD; Boston, MA

This was an excellent clinical study comparing the standard, Fernandez osteotomy with iliac crest corticocancellous graft with a new approach, using only cancellous graft. This technique is only possible due to the stability allowed by the new Synthes' Pi plate. Nine consecutive patients had the traditional osteotomy and grafting (Group I) and eight had the new technique (Group II). The average ages were similar (50 and 46, respectively), the delay from the time of injury was similar (62 weeks and 67 weeks, respectively), the degrees of deformity were similar (but the data was not given), and the followup was similar (14 months and 22 months, respectively). All osteotomies healed. The average ulnar variance improved from 2.6 mm to 1.3 mm in Group I, and from 5.6 mm to 1.5 mm in Group II. The average volar tilt improved from -20 degrees to +1 degree in Group I, and from -10 degrees to +3 degrees in Group II. The results were Group I: 3 excellent, 4 good, 1 fair, and 1 poor; compared to Group II: 4 excellent, 3 good, and 1 poor. Both the poor outcomes were in Workers' Compensation cases, and one had severe intracarpal trauma. The paper was reviewed by Thomas Trumble, who noted that the groups were not entirely comparable, and questioned if there was a selection bias. However, my feeling from hearing both the paper and the review, was that this was a very exciting technique that had been adequately tested to suggest it to the surgical community. We all know how difficult it can be to contour the corticocancellous graft properly and how nearly impossible it is to get it into the osteotomy site. I ususally need to employ a few choice swear words to get it to fit. I would note that the only complication was that five patients in each group required plate removal. This is not a criticism of the technique, since they both use it. However, I have found that if you enter through the third compartment (a bit radial on the superficial layer and a bit ulnar on the deep layer), you have enough soft tissue to cover the plate. I have not had to remove any plates since using this technique. An obvious question arises: if the osteotomy can be done with cancellous bone, and Collagraft has been shown to be equivalent to cancellous bone [J Bone Joint Surg Am 1997 Apr;79(4):495-502, Treatment of acute fractures with a collagen-calcium phosphate graft material. A randomized clinical trial.Chapman MW, Bucholz R, Cornell C], could this not be done without any iliac crest harvest at all? If the criteria of excellence include changing clinical practice and stimulating further research, this paper rates excellent on all grounds.

A Prospective, Randomized Comparison of Corraline Hydroxyapitite and Autogenous Bone Graft in the Treatment of Distal Radius Fractures

John Wyrick, MD, Christopher Spieles, MD, and Irfan Ansari, MD

This was a prospective, randomized clinical study of 36 comminuted distal radius fractures in 35 patients, all treated with external fixation and supplementaly K-wire fixation. Group I consisted of 16 patients treated with iliac crest bone grafting and Group II had "coralline hydroxyapetite", which presumeably was Interpore's Prosteon. [Although the authors did not say if it was the newer 500R, I suspect it was the earlier version of the product that had less of the calcium carbonate changed into calcium phosphate, which makes the product much slower to incorporate, and in my opinion, too slow to incorporate. Interpore apparently agrees, since they came up with the 500 R (for resorbable). For further discussion and histology, see the navigation button Basic Science (to the left on your screen), and choose the paper Types of Bone Graft Substitute.] The fixators were removed at six weeks in both groups. The average range of motion, grip strength, and outcome were not statistically different for the two groups. The cost of the product was equal to the surgeon's fee, but Group II did not require an overnight stay in the hospital. There was no comment about the rate of incorporation, which to me is a very important consideration, and there were 10 patients lost to followup (29%). I have not had to admit any of my patients who have had an iliac crest bone graft since I have started to place a Marcaine block prior to closing the hip incision, so there would not be that benefit in my patients. The area of bone graft substitutes is a very important one for the surgeon to stay abreast of, and this paper demonstrates the advantages of avoiding iliac crest complications by using "bone in a bottle." The question is, which bone in a bottle? Prospective, double blind studies are needed, and the one cited above by Chapman, from the J Bone Joint Surg Am 1997, is the only one of which I am aware.

Norian SRS vs. Conventional Therapy in Distal Radius Fractures: Minimum One-year Follow-up in 323 Patients

Charles Cassidy, MD (Boston, MA), Jesse Jupiter, MD (Boston, MA), Michelle Delli-Santi, BS (Norian, Cupertino, CA), Jeffrey Husband, MD, Charles Leinberry, MD, and Brent Constantz, PhD (Norian, Cupertino, CA)

This was the data upon which Norian Corporation had their carbonated hyproxyapetite cement, SRS (for Skeletal Reconstruction System), approved by the FDA. It was a very complex undertaking, with vast amounts of data collected, and the authors are to be congratulated. The study was run by Dr. Amy Ladd of Stanford. The study was a prospective, randomized, culticenter clinical study of distal radius fractures. The patients were stratified by fracture type, bone density as measured by DXA scanning, and type of treatment chosen by the patient and surgeon (either cast or ex fix), and randomized to either the control group (conventional treatment) or treatment with SRS. With this many treatment arms, a large number of patients were required, and there were 162 in the conventional treatment group and 161 in the SRS group. The conventional treatment (cast of ex fix) group was immobilized for 6-8 weeks, and the SRS group immoblized in a cast for 2 weeks and a splint for 4 weeks. The large amount of data collected allowed many different comparisons to be made, more than could be presented at the ASSH or presented here. To summarize: although there were many early differences between the groups, they usually did not persist beyond 3 months. The authors claim that the loss of reduction was similar between the two groups, but others looking at the same data have felt that the loss of reduction in the SRS patients that did not have supplemental K-wire fixation was greater, and the FDA has suggested that "use of the cement does not eliminate the need for other stabilizing devices, such as hardware and pins, in patients who would normally need them. This is espeically true for patients with very complex fractures." (http://www.fda.gov/bbs/topics/ANSWERS/ANS00931.html) The infection rate was significantly higher in the control group, due to the use of external fixation, but this should not be clinically relevant, given the FDA's suggestion that SRS not be used without external fixation, if the surgeon felt that normally ex fix was indicated. The authors concluded that "Norian SRS appears to be safe and effective in the management of distal radius fractures." I would agree, with several caveats: the surgeon needs to be sure to take Norian surgeon's training course and closely follow the company's recommendations. Although we all expect to see a large amount of off-label use of this product, the surgeon is strongly advised to speak to the experienced surgeons who have used SRS in the study and learned a great deal about its strengths and weaknesses. There is no need to repeat the lessons already learned by these excellent surgeons.

Arthroscopic Assisted Reduction of Distal Radius Fractures

William Geissler, MD Jackson, Mississippi

This was an excellent clinical study of 33 patients who had an intraarticular distal radius fracture with > 2mm of articular displacement after attempted closed reduction. There were 7 Type B1, 1 Type B2, 3 Type B3, 9 Type C1, 3 Type C2, and 10 Type C3 fractures (AO Classification). There were, in addition to the bony injury, TFCC tears in 13 (40%), with 8 peripheral tears, 4 radial avulsions, and 1 central tear. A complete or partial SL tear was found in 12 (36%) and a complete or partial LT tear in 4 (12%). All patients had an arthroscopically-assisted reduction, plus percutaneous pin fixation alone in 18, plates and K-wires in 11, and cannulated screws in 4. The general procedure was to reduce the radial styloid first, then elevate the depressed fragments, and then the volar medial complex. SL tears of Geissler Grade II were pinned for 6 weeks, Grade III and IV had an open "reconstruction". [Will did not discuss the type of "reconstruction", but I believe he meant "repair." Due to the various types of repair (Taleisnik), substitution (Blatt or Linscheid), or true reconstruction (Weiss {bone-ligament-bone}or Nelson {using the transverse carpal ligament, which was presented at the previous year's IWIW meeting}), I think it is important to be clear which surgery is done.] The articular reduction was anatomic (< 1 mm) in 25 and nearly anatomic (1 mm) in 8. There were twenty excellent, 10 good, and 3 fair results (Gartland and Werley). Simple articular fractures (Type B) had 82% (9/11) excellent results compared with 50% (11/22) complex articular fractures (Type C). Partial tears of the SL ligament did not adversely affect results (6/8 excellent results). However, the higher grade (III and IV) tears occurred more frequently in the Type C fractures, and did have an effect: Type C without Type III or IV tears had an excellent result, while those with this level of tear had only good or fair results. Additionally, none of the LT ligament tears had an excellent result, but the low number (4) made generalizations difficult. Interestingly, the presence of a TFC tear did not adversely affect the results. Will concluded that arthroscopy was a valuable aid in treating these fractures, somewhat like a mini-c-arm. Someone from the audience called it the "gold standard", but this view was not supported byothers, who took a more limited view, and Will reiterated his opinion that it was a "valuable aid." His circumspect attitude was appreciated by many. This is a very important paper, by a thoughtful and reliable investigator. The role of arthroscopy has not yet been established, but some role can no longer be denied. One observation: there has been a controversy in the literture regarding whether the initial displacement or the final reduction affects outcome most. This study would posit a third possibility: it is the soft tissue injury that best predicts outcome. Other researchers (Bain in Australia and Lindau in Sweden, to mention two) are also working in this area.

Correction of Distal Radius Malunion Fractures Using the Norian SRS

Riccardo Luchetti, MD

The complete manuscript and xrays are available here. This is an interesting, preliminary study of three patients who had an osteotomy performed for malunion. Instead of inserting tricortical bone graft (the standard method) or cancellous graft (see Jupiter's paper, above), the author stabilized the osteotomy with K-wires and inserted Norian SRS. This has the advantages of not requiring iliac crest bone or a dorsal plate. Norian has been shown to have a large amount of settling in distal radius fractures (see the FDA report , page 10, Table 8). Norian SRS had loss of radial length of 4.7 + 4.3 mm at 3 months compared to a control of 4.0 + 4.3, and a loss of 4.5 + 4.3 compared to a control of 3.7 + 4.0 at 12 months. However, settling does not seem to be the problem with osteotomy as it is with fractures, at least as seen by these three cases. Norian is remodeled fairly slowly, but that may not be a problem in this application.

This is an interesting approach and should be investigated further.

As a member of the FDA Panel that approved Norian SRS for use in unstable distal radius fractures, I feel it is important to urge readers not to attempt to use Norian SRS off-label. We have seen many examples of how these new materials do not behave as one might think, and all new indications should be evaluated carefully as part of a controlled study, with the results (either positive or negative) shared with the rest of the surgical community. Personally, I do not feel we will know the exact indications for the in-situ hardening cements (there are at least three on the market in Europe; for a listing, see the paper under Basic Knowledge, Types of Bone Graft Substitutes, and scroll down to Mineral Cements) for at least a decade. However, we will never reach that point if surgeons use them outside of controlled studies. (See also my comments under Norian SRS vs. Conventional Therapy in Distal Radius Fractures, reviewed above.) -reviewed by David Nelson, MD

All of the abstracts as well as some of the Instructional Course Lectures are on-line. Some papers you might like to look at include:

Pin Site Care During External Fixation in Children: Results of a Nihilistic Approach

This contribution to the ongoing controversy regarding pin site care suggests that daily showering without specific pin site care can result in only a 4% complication rate. No pins needed removal.

A Randomized Controlled Trial of Indirect Reduction and Percutaneous Fixation Versus ORIF for Displaced Intra-Articular Distal Radius Fractures

An excellent paper by a well-known group of investigators, including one of our own Editors. This paper will put the pressure on the ORIF guys to show a better outcome compared to percutaneous methods.

Do Fractures Heal by the Reinduction of Genes Expressed During Bone Development?

An interesting basic science paper in mice that documents what we have guessed: fracture healing utilizes a similar pathway to skeletogenesis.

Delayed Postoperative Injection of Osteogenic Protein-1 (OP-1) in the Canine Noncritical-Sized Defect Model

Allthough the cytokines are not curently (Feb 24, 1999) available for use in humans in the US, they are a hotbed of research. Indeed, the ORS used to be a biomechanics meeting, and now it is a cytokine, tissue engineering, and gene therapy meeting! This paper lets you see what will be coming down the pike in the future.

Synergism of Bone Marrow and rhBMP-2 in Segmental Bone Repair

Another cytokine paper that shows what will be possible in the future.

Instructional Course Lecture: Advances in Distal Radius Fracture Management

An excellent symposium with William Geissler, Jesse Jupiter, Matthew Putnam, and William Sieitz; moderated by Scott Wolfe.

The use of BMP-2 in Interbody Fusion Cages: Definitive Evidence of Osteoinduction in Humans

You may wonder why I include a paper on lumbar fusions on this site. The reason is that this technology will be applied to distal radius fractures in the future, and was so important that Scott D. Boden, MD, was given the Kappa Delta/Young Investigator Award for this work. The paper is worth review if you have an interest in bone grafting alternatives. Also, be sure to visit the paper on this site on bone graft alternatives, available through the Basic Knowledge navigation button (on the left of your screen), under Types of Bone Graft Substitutes.

The abstracts for the ORS are on a protected site and I cannot directly link to them. I have asked the authors of all papers relating to distal radius fractures and bone grafting for permission to post their work. I will post them as I get permission and have time to format them. Stay tuned.

THE SIGNIFICANCE OF THE IMMUNE RESPONSE IN THE FATE OF BONE ALLOGRAFTS
Wooley, P.H., Nadim, Y, Schaefer, C.J., and Ryan, J.R. Department of Orthopaedic Surgery, Wayne State University, Hutzel Hospital 1S, 4707 St Antoine Blvd,
Detroit, MI48201. (313)745-6828 FAX (313) 993-0857, p_wooley@wayne.edu