March 1, 2001, 3 p.m. - 6 p.m.
Sheraton Palace - Twin Peaks Room
Two Montgomery Street
San Francisco CA 94105
Phone: 415-512-1111
This meeting took place during the AAOS convention in San Francisco.
Thank you to our meeting sponsors:
the medcom group, ltd.
The Stone Foundation for Sports Medicine and Arthritis Research
Agenda
| INTRODUCTION | 3:00 p.m. |
| Cryolife Data on the Current Status of Meniscus Allografting in the
U.S. and Plans for the Future David M. Fronk, M.S. Cryolife, Inc., Kennesaw, Georgia |
3:10 p.m. |
| Protective Effects Of Meniscal Allografts Mora G*., Forriol F**., Ripalda P.**, Alvarez E**. *Instituto COT. Clinica Quiron. Valencia. SPAIN **Orthopaedic Research Laboratory. University of Navarra. SPAIN |
3:25 p.m. |
| Meniscal Allografts - Indications in patients with grade IV articular
cartilage changes Mohi El-Shazly, M.D. Droitwich Knee Clinic, Droitwich Spa, England |
3:40 p.m. |
| Is DNA Fingerprinting a Tool in Evaluating the Success Rate of Viable
Meniscal Allografting? Karl F. Almqvist, M.D., T. Lootens, René Verdonk, M.D. Department Of Physical Medicine And Orthopaedic Surgery University Hospital Of Ghent, Gent, Belgium |
3:55 p.m. |
| Meniscal Lesion Repair After Implantation of New Porous Polymers. A
Study in Dogs T.G. van Tienen, P. Buma, R.G.J.C. Heijakants*, N.G. Lieuwes, J.H. de Groot*, R.P.H. Veth Orthopaedic Research Laboratory, University Medical Centre, Nijmegen, The Netherlands *Plymer Chemistry, University of Groningen, The Netherlands. |
4:10 p.m. |
| Update on Meniscal Allografting in Arthritic Knees Kevin R. Stone, M.D., Ann Walgenbach, R.N., M.S.N, N.P. The Stone Clinic, San Francisco, CA |
4:25 p.m. |
| Porcine Xenografts for Orthopaedic Applications Stone KR, Walgenbach AW, Turek TJ, Galili U CrossCart, Inc., San Francisco, CA |
4:40 p.m. |
| Advances in the Basic Science of the Normal and Remodeling Meniscus Cahir McDevitt, Ph.D** Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation |
4:55 p.m. |
| The Future of Meniscal Transplantation and Replacement in Europe Henrik Aagaard, M.D., Ph.D Department of Orthopaedic Surgery RASK Koege, Denmark |
5:15 p.m. |
| Combined Meniscal Transplant and ACL Reconstruction Christopher Harner, M.D.** University of Pittsburg Medical Center, Center for Sports Medicine |
5:30 p.m. |
| The Present Status and Future of Meniscal Transplantation Allan E. Gross, M.D., F.R.C.S. Mt. Sinai Hospital, University of Toronto, Canada |
5:45 p.m. |
| Presentations to be eight minutes followed
by discussion. **Presentation to be twelve minutes followed by discussion. |
|
Abstracts
CryoLife Data on the Current Status of Meniscal Allografting in the United States
Authors: D.M. Fronk, M.S., J.D. Lehman, B.S.
CryoLife Inc., Kennesaw, Georgia
Introduction: CryoLife's first meniscal allograft was implanted in November
of 1989. Since then, over 3500 grafts have been provided for implant. These
grafts have been implanted by over 450 surgeons throughout the U.S. In the
early stages of meniscus reconstruction, clear indications of the procedure
had yet to be shown. Through an initial study, those parameters were set
to clearly identify future candidates for meniscal reconstruction. The purpose
for this study was to provide clinical outcome data evaluating the mid-term
performance of cryopreserved meniscal allografts.
Methods: One hundred thirty-six patients with a mean age of 35 (range 17-58)
were retrospectively reviewed based on objective and subjective data obtained
through a patient mailing. Thirteen surgical sites were included. Clinical
outcome was assessed using a quality of life questionnaire including a modified
version of the Lysholm activity scoring system.
Results: The range of follow-up was from 36-96 months (mean 5.1 years). The
average post-operative Lysholm score was 79 ± 18 with 80% of patients
rating their current knee function as normal or nearly normal. The average
post-operative pain level was rated low at an average of 2.7 on a 10-point
scale. Ninety percent of patients reported their surgery as a success, while
93% reported that they would have the surgery again if presented with the
same situation. There was a 76% good to excellent result of those patients
at >5 years follow-up.
There was an 86% success rate based on re-operation. A total removal was
indicated in 6 patients with a partial removal in 14 patients. Six of 7 partial
removals were performed on patients with pre-operative Fairbanks changes
of Stage III & IV with 4 of the same patients presenting with Grade IV
Outerbridge changes.
Conclusion: Meniscus reconstruction using cryopreserved meniscus allografts
is shown to have successful mid-term results in most patients who have indications
of isolated pain, no greater than Stage II Fairbanks or Grade IV Outerbridge
changes at the time of surgery, and who have previously undergone a total
or partial meniscectomy.
Is DNA Fingerprinting a Tool in Evaluating The Success Rate of Viable Meniscal Allografting?
Authors: K.F. Almqvist, T. Lootens, R. Verdonk.
Department of Physical Medicine and Orthopaedic Surgery,
University Hospital of Ghent, Gent, Belgium.
Aim of the study: Meniscal allografting has been reported to allow for slow
integration of recipient fibrochondrocytes into the transplanted meniscal
tissue. The integration of recipient fibrochondrocytes into human viable
meniscal allografts was evaluated in this study.
Methods: 21 of 98 patients who had received an allogenic viable meniscal
transplant, underwent a control arthroscopy. A biopsy specimen was harvested
from the implanted menisci during this second operation. DNA fingerprinting
was performed to evaluate possible ingrowth of the meniscal allograft by
acceptor fibrochondrocytes.
Results: The compared DNA region showed complete matching in 7 cases, incomplete
matching (cell population of the recipient and the donor) in 4 cases, and
non-matching in 3 cases. The remaining 5 cases could not be analyzed due
to culture failure. Two patients underwent a second arthroscopy. The initial
DNA determination was mixed and non-matching, and at the second arthroscopy
this became matching and mixed DNA pattern, respectively.
Conclusion: These findings suggest partial or complete ingrowth of the transplanted
meniscus by acceptor fibrochondrocytes. However, non-matching does not imply
a graft failure as evidenced by a simultaneous clinical examination using
the Hospital for Special Surgery score, and by the macroscopic aspect during
control arthroscopy. MRI performed prior to control arthroscopy and pathological
examination of the retrieved fragment both showed a certain degree of mucoid
degeneration in case of a non-matching DNA pattern.
Protective Effects Of Meniscal Allografts
Authors
Mora G*., Forriol F**., Ripalda P.**, Alvarez E**.
*Instituto COT. Clinica Quiron. Valencia. SPAIN
**Orthopaedic Research Laboratory. University of Navarra. SPAIN
Objective: To quantify histologic changes of articular cartilage after medial
meniscectomy and after medial meniscectomy followed by immediate reconstruction
with meniscal allograft or Aquiles tendon allograft, with reference to the
development of degenerative arthritis.
Methods: Three groups of eight sheep each were used for the study. (1) meniscectomy,
(2) meniscal allografts and (3) Aquiles tendon allograft. Horns of the reconstructed
menisci were secured with non-absorbable transosseous sutures and absorbable
sutures were used for the body of the menisci. Animals were euthanized after
6 months and articular cartilage was histologically studied according to
Mankin's score for osteoarthritis.
Results: Significant differences were found among all the groups with the
highest score in meniscectomy (worst) and lowest score in meniscal allograft
reconstruction (best) although changes were always found compared to a normal
(control) knee.
Conclusions: Meniscal transplantation provides protection, although not complete,
against damage to the articular cartilage after a meniscectomy.
The Present Status and Future of Meniscal Transplantation
Author: Allan E. Gross M.D., F.R.C.S.(C)
Mt. Sinai Hospital
University of Toronto
Experimental meniscal transplantation in rabbits has been performed to evaluate
the healing response of free meniscal allografts. Fresh, frozen, and frozen
irradiated allograft menisci were inserted with interrupted sutures. Macroscopic,
microscopic, biochemical and viability studies were performed. Meniscal allografts
healed peripherally. The donor cells died and the meniscus was repopulated
by host cells within six months. Tritiated cytidine radiography revealed
that fresh allografts started with 90 % viable cells, while frozen cryopreserved
menisci had 4% viable cells. Even in fresh grafts by two months, most cells
died and repopulation was necessary. During the period of cell repopulation
the menisci remained structurally intact. There was a mild immune response
to allograft tissue compared to autograft menisci. Overall experimental meniscal
transplantation by many investigators has supported the clinical use of meniscal
allografts.
From 1972 to 1992, 126 osteochondral allografts were carried out for post
traumatic defects of the knee. As part of that series 47 meniscal allografts
were performed as part of a composite osteochondral plateau graft for trauma.
There was an 85% success rate for the entire series at an average follow
up of 7.5 years. There was no relationship between failure and the need for
meniscal allograft. In a more recent study of 60 knees that had received
fresh femoral condylar allografts for traumatic defects, 10 meniscal allografts
were transplanted. At a mean follow up of 10 years there was an 85% survival
with patients requiring a meniscal transplant doing as well as those that
did not. Arthroscopic examination of 10 allograft menisci at an average follow
up of 4.5 years revealed structurally intact menisci with some degenerative
changes and viable cells.
The issues to be considered for the future for meniscal transplantation are
the indications, preparation, sizing, surgical technique and evaluation.
The potential indications are the post menisectomy early arthritic knee with
or without an osteotomy, the post menisectomy knee undergoing ligament reconstruction,
fresh meniscal tears that cannot be repaired and the meniscus as part of
an osteochondral allograft. In our experience fresh tissue does best but
the logistics are more difficult and there is the risk of disease transmission.
Plain x-rays are adequate for sizing the medial meniscus but C.T. or M.R.I.
is more accurate for the lateral meniscus. In our series direct suturing
was used but other authors advocate bone blocks. Evaluation of meniscal allografts
should be done by arthroscopic examination and biopsy.
Meniscal Allografts - Indications in Patients with Grade IV Articular Cartilage Changes
Authors: Strover AE, El-Shazly M
Droitwich Knee Clinic, Droitwich Spa, UK
Introduction: The function of the meniscus has been well documented in recent
years, mainly following long-term follow-up of patients who had total meniscectomies
in the past. The consequences of meniscectomy in these patients include osteoarthritic
change due mainly to high contact stresses developed in the absence of the
meniscus.
A number of recent studies have shown gratifying short-term results of meniscal
allografts. The objective of meniscal allograft transplantation is relief
of pain and improvement of function. By restoring joint mechanics it should
also prevent long-term arthritic degeneration. While relief of pain is achieved
in most cases, its effect on prevention of degenerative joint disease has
not been shown. The procedure is generally recommended for patients with
little or no joint surface damage
We report on the short-term results of meniscal allografts performed for
a small cohort of patients most of whom had significant long standing joint
surface damage.
Material & Methods: In the period from May 1996 to June 2000, 12 meniscal
transplants in 10 patients performed at the Droitwich Knee Clinic, were monitored
prospectively. Age ranged from 19 to 53 years (mean 33.3). There were two
females and eight males. There were six medial and six lateral menisci. Mean
follow-up period was 24.6 months (range 6 to 53 months). Most were secondary
or tertiary referrals, with a mean of 3.6 previous procedures (range 2 -
9), and a mean time from onset of symptoms of 9.3 years (2.5 - 14 y). Seven
of the ten patients had articular surface changes (grade II - IV).
Each patient filled out a detailed preoperative questionnaire, from which
a pre-operative Lysholm score and Tegner activity rating was derived. Postoperatively,
patients were asked to fill out a follow-up questionnaire at six months,
1 year and yearly thereafter. The forms included detailed questions on symptoms
including the Borg scale for pain (0 - 10), the presence of mechanical symptoms
such as locking or giving way. Postoperative Lysholm and Tegner scores were
recorded as well as the IKDC system. A thorough clinical examination was
performed at each time point particularly recording the presence and size
of any effusion, joint line tenderness and range of motion. Isokinetic testing
was used to monitor improvement in muscle function prior to return to sporting
activity.
Second look arthroscopy was performed routinely at three months for all patients.
Pre and postoperative X-rays and MRI scans were analysed.
Results: Pain was the main pre-operative symptom in all cases with a mean
value of 5.3 on the Borg scale (range 3 to 8). Seven patients had recurrent
or persistent effusion and 5 cases had mechanical symptoms such as locking
or giving way.
The mean pre-injury Tegner rating was 8 (range 3 - 9). Mean pre-operative
scores were 2 (0 - 5). At a mean follow up of 24 months, the mean Tegner
rating had improved to 3.2 (0 - 4). Three patients had no improvement on
preoperative activity. Another two were worse and the rest had improved (overall
mean improvement of 1.3 Tegner grades).
Lysholm scores improved from a preoperative mean of 63.3 (range 29 - 95)
to 76.4 (48 - 99) postoperatively.
Of the 9 patients who filled out their subjective IKDC questionnaire, 5 (56%)
rated their knee as nearly normal. 3 as abnormal and 1 remained severely
abnormal.
Improvement in pain however was disappointing with a mean preoperative Borg
score of 4.6, which improved to 3.5 postoperatively.
Discussion: Contrary to recommendations in the literature this study includes
patients who have been referred with long standing problems, including multiple
operative procedures in the past and grade IV changes affecting the weight-bearing
surfaces in many cases. Although those who had grade IV changes did not fare
very well, there was an overall improvement in pain and function and activity.
The two patients with the highest postoperative Lysholm scores (96 & 99
respectively) had had no joint surface damage preoperatively and no pain
postoperatively (0 on the Borg scale). However, return to pre-injury level
of activity is by no means the rule. Only one patient was able to return
to the same level of sporting activity. In general, however, all but one
patient reported some degree of improvement.
Conclusion: It is difficult to draw firm conclusions from this small cohort
with short-term follow-up. However, it appears that although it is possible
to achieve some improvement in patients with severe articular surface damage,
the results are far better if the patient is referred early enough prior
to the onset of severe degenerative joint disease. This begs the question
whether this procedure should perhaps be recommended for patients who have
had meniscectomies and have little or no symptoms.
Meniscal Lesion Repair After Implantation Of New Porous Polymers. A Study In Dogs
Authors: T.G. van Tienen, P. Buma, R.G.J.C. Heijkants*, N.G. Lieuwes,
J.H. de Groot*, R.P.H. Veth
Orthopaedic Research Laboratory, University Medical Centre, Nijmegen,
The Netherlands
*Polymer Chemistry, University of Groningen, The Netherlands
Purpose of the study. Bucket-handle lesions in the avascular part of the
meniscus do not heal spontaneously. Connecting the lesion to the meniscus'
vascular periphery by implanting a smart scaffold in a partial thickness
defect may induce healing.
Materials and methods. We created partial thickness defects in 22 menisci
of 16 Beagle dogs with lesions which had full thickness longitudinal extensions
in the avascular meniscus substance. In 12 lateral menisci a newly developed
porous degradable copolymer implant of 50/50 L-lactide/e-caprolactone was
sutured into the defect. 10 meniscal defects were left empty and served as
controls. Healing of the lesion, repair of the defect and consequences for
the tibial cartilage were evaluated macroscopically, routine histologically
and immunohistochemically.
Results. Six months after surgery all polymers were completely incorporated
and resembled normal meniscal fibrocartilage, which was confirmed by matrix
staining. Ten cases in the implant group showed at least partial healing
of the lesion compared to four in the control group. Also the ingrown tissue
in the implants more frequently showed a fibrocartilaginous aspect than in
controls. Cartilage degeneration with ulcera occurred three times in the
implant group while in controls all cases had this aspect. In all implant
cases only few macrophages and giant cells were seen.
Conclusions. In meniscal defects with a porous polymer, more healing of the
longitudinal full thickness lesions occurred and more fibrocartilage was
detected in the implants. A degrading porous polymer seems an adequate scaffold
to enable repair tissue to reach the lesion and restores the fibrocartilage
in the defect rapidly. This method might be adequate to repair lesions in
the avascular zone of the meniscus.
Porcine Xenografts for Orthopaedic Applications
Authors: *+Stone KR, *Walgenbach AW, +Turek TJ, **+Galili U
*The Stone Clinic, 3727 Buchanan St., San Francisco, CA
**Rush University, Chicago, IL
+CrossCart Inc., SanFrancisco, CA
More than 350,000 cruciate ligaments are reconstructed in the U.S each year,
70% of which use the patient's own patellar tendon. The autogenous harvest
is associated with anterior knee pain, weakness, scar formation, and patella
tendon complications. Substitute tissues include the hamstrings and allografts
with varying degrees of success and complications.
Efforts to replace the cruciate ligament with synthetic materials have failed
and are no longer in use in the U.S. Early efforts to replace the cruciate
ligament with bovine xenograft tissue were successful for some of the patients
who received the tissue. Other bovine graft patients suffered complications
from synovitis, graft loosening, failure of fixation, and abrasion. Much
of the synovitis was attributed to the high levels of glutaraldehyde in which
the product was packaged.
It is our belief that the ideal tissue replacement would be a de-antigenated
porcine patellar tendon due to similar biological, anatomical and biomechanical
properties to human tissue. We have identified the key antigens that cause
rejection and have developed a processing technique of de-antigenation within
the imposed constraints that the end product exhibit similar biomechanical
characteristics as native tissue.
This talk will present the results of our work identifying the antigens in
a porcine bone-patellar tendon-bone device, describing the enzymatic removal
technique, testing the implants in animal immunologic models, and comparing
the resulting initial biomechanical properties of the device to human allografts.
Additional work will be presented reviewing development of porcine graft
tissues in the areas of bone, meniscal and articular cartilage grafts.
The Future of Meniscal Transplantation in Europe
Authors: Henrik Aagaard, Denmark
European Meniscal Transplantation Group (EMTG)
During the past two decades experimental and clinical studies dealing with
meniscal replacement have been reported from various parts of Europe, and
most of them are rather recent. Studies dealing with both meniscal transplantation
and other types of meniscal replacement have been reported. Meniscal replacement
in Europe is currently rather sporadic and only very few clinics offer it
as a routine treatment. Until recently meniscal replacement was not coordinated
and formalized meeting activity were non-existent.
The health care systems in Europe vary from country to country, and there
are large cultural differences from north to south and from east to west,
but there seems to be an increasing European interest in the subject of meniscal
replacement.
Based on an increasing need to meet and share experiences, the European Meniscal
Transplantation Group (EMTG) was founded in London September 2000. The EMTG
is informally affiliated to the European Society of Sports Traumatology,
Knee Surgery, and Arthroscopy (ESSKA), and the group plans to meet every
second year during the ESSKA Congress.
The EMTG intends to establish and maintain contact with the Meniscal Transplantation
Study Group in USA, and hope to benefit from their greater experience dealing
in meniscal replacement. Hopefully the contact will become one of mutual
benefit within the coming years. The EMTG intends to contact persons and
clinics in Asia who have reported on meniscal replacement.
Those subjects that the EMTG would like to emphasize in the years to come
are standards for patient evaluation, tissue banks (centralization, industry
vs. healthcare system, preservation techniques, rehabilitation protocols,
common clinical databases, surgical techniques, experimental animal models,
coordination of future studies, development of new ideas.
The aim of the EMTG is to influence the future of meniscal transplantation, rather than to control it.