2003 Meniscus Transplantation Study Group
MENISCUS TRANSPLANTATION STUDY GROUP
February 6, 2003, 3:00 p.m. - 6:00 p.m.
Ritz Carlton Hotel, Lasalle Room
921 Canal Street
New Orleans, Louisiana
| INTRODUCTION | 3:00 p.m. |
| Meniscal Allografts - the European Experience René Verdonk, M.D., Ph.D. Department of Orthopaedic Surgery, Ghent University Hospital, Belgium |
3:20 p.m. |
| Normal vs Transplanted Menisci: Evaluation of Extrusion
Using MRI and US. A Preliminary Report René Verdonk, M.D., Ph.D. Department of Orthopaedic Surgery, Ghent University Hospital, Belgium |
3:40 p.m. |
| Biomechanical, Histologic, and Radiographic Indices in an Ovine Post-Meniscectomy Model Scott Rodeo, M.D. Hospital for Special Surgery, New York, NY |
4:00 p.m |
| A Clinical and Objective Evaluation of Meniscus Allograft
Transplantation at Minimum Two-Year Follow-Up Hollis G. Potter, M.D. Hospital for Special Surgery, New York, NY |
4:20 p.m. |
| Meniscal Allografts in Patients with Severe Arthrosis Kevin R. Stone, M.D. The Stone Clinc, San Francisco, CA. |
4:40 p.m. |
| Role of Meniscus Allografts Alone and Combined with ACL Reconstruction or Osteochondral Autograft Transfer Procedures Frank R. Noyes, M.D Cincinnati Sportsmedicine and Orthopaedic Center, Cincinnati, OH |
5:00 p.m. |
| Long Term (Five to Six Years) Follow-Up of Collagen Meniscus
Implants: A Prospective Clinical Study William G. Rodkey, D.V.M. |
5:20 p.m. |
| DISCUSSION | 5:40 p.m. |
MENISCAL ALOGRAFTS - THE EUROPEAN EXPERIENCE
René Verdonk, M.D., Ph.D.
Department of Orthopaedic Surgery, Ghent University Hospital, Belgium
Introduction: Michael Krogsgaard, MD, PhD, coordinated a meniscal transplantation symposium in Kopenhagen in September 1998. The European consensus is published in the Scandinavian Journal of Medicine & Science in Sports (1999, 9:134-187). An extensive overview of problems and solutions regarding this issue has been assembled, leading to the conclusion that meniscal transplantation is still somehow an experimental approach to the meniscectomized knee. Several solutions are suggested, based on short-term and long-term results. It is clear that this experience has to be confronted with other modalities of treatment in case of evolving degenerative joint disease of the knee.
HARVEST AND CONSERVATION OF MENISCAL ALLOGRAFTS
Summary: Menisci are ideally harvested within 12 hours after the start of
ischemia. When frozen no cells survive. Cryopreservation allows the fibrochondrocytes
to be preserved in 10 to 30 % of the cases. Frozen and cryopreserved allografts
can be stored and thus be readily available. In case of viable meniscal
allografts it appears that the ideal time for implantation is 10 to 14
days after harvesting.
Frozen meniscal allografts: Meniscal implants are required to be readily
available for transplantation. The material should be safe regarding transmissable
diseases. Clinical immune response should be eliminated.
The meniscal bodies are removed from general organ donors. The freezing process
can then be induced as fresh-frozen or following cryopreservation technique.
The fresh-freezing process brings the material down to -78°C. In the
cryopreservation process the deepfreezing is progressive, using DMSO. The
freezing temperature is -178°C. According to Fabbriciani the cryopreservation
technique does not induce better histological results after implantation.
Viable meniscal allograft harvesting and conservation techniques: Donor
menisci are removed in an operating room under strict aseptic conditions,
after the procurement of other organs from heart-beating (multiple-organ
donors) or non-heart-beating donors. The cold ischaemia time must not exceed
12 hours, during which the meniscus remains viable. Through a transverse
arthrotomy, the lateral collateral ligaments and cruciate ligaments are divided
and the knee is dislocated anteriorly.
The menisci are removed and can then be transported in a sterile physiological
solution to the tissue bank. The specimens are then put in culture, using
Dulbecco's modified Eagle's medium with 0.002 M L-glutamine, 1/1000 antibiotic-antimycotic
suspension (streptomycin 10 mg/ml, penicillin 10 U/ml, fungizone 0.025 mg/ml)
and 20 % of the recipient's serum. This serum has been prepared and frozen
from the recipient's blood by centrifugation.
The menisci are then stored in a plastic container (DANCON; Teknunc - 4000
Roskilde, Denmark) to which 70 ml of incubation medium are added. The containers
are placed in a modular incubation chamber (Flow Laboratories - Del Mar,
California, USA) at a constant temperature of 37°C and under continuous
air flow (95 % air and 5 % CO2). Humidity is controlled by placing an open
receptacle filled with sterile water in the incubation chamber. The incubation
media are replaced every three days under sterile conditions.
The recipient's sera have been stored at -18°C and are appropriate for
clinical use for a maximum of 6 weeks post-puncture. Results have shown that
the transplanted allograft remains viable, producing fibrochondrocytes, proteoglycans
and also collagen fibre structures. From the moment of implantation a normal
cellular function can be expected, inducing potentially normal meniscal function,
which may prove to be of great advantage compared to frozen allografts.
MENISCUS TRANSPLANTATION: PREOPERATIVE PLANNING
Summary: Precise preoperative planning is mandatory to obtain good clinical
results of meniscus transplantation. Any pathology in addition to the missing
meniscus should be detected, including malalignment, and ligament instability.
A full status of the changes in the cartilage should be made.
Preoperative planning
X-rays: Anterior-posterior views are essential to exclude any major bone
pathology. They will also indicate potential subchondral condensation and
potential cystic degeneration.
Standing X-rays: To properly determine any axial malalignment and potential
joint space narrowing, standing X-rays are mandatory in the preoperative
evaluation of the transplant recipient. Loadbearing X-rays in 45° of
flexion and 10° of ray inclination allow for better visualization of
degenerative joint disease.
Bone scan: Disturbed homeostasis of the subchondral bone is appropriately
visualized by Technetium bone scanning. It is an excellent method to confirm
mechanical pathology. Moreover, it allows for follow-up evaluation. Functional
normalization of the joint after meniscus transplantation may result in a
normalization of the bone scan.
CT scan: Both the donor's and the recipient's joint can be sized using CT
scan. It is appropriate to use this technique for evaluating the recipient's
knee joint, as correct information about size of the allograft meniscus is
obtained when the allograft is removed from the donor and measured.
MR evaluation: MR evaluation is mandatory to illustrate preoperative findings.
Indeed, meniscal allografting is only indicated in total meniscectomy. Theoretically
dynamic MRI may give valuable information about the mechanical behavior of
the knee (ligaments, menisci(us)) before the operation, and after meniscus
replacement.
Arthroscopy: Arthroscopy is the only means to evaluate the chondral status
of the knee and thus to exclude extensive chondral deterioration (from grade
4). Obviously, arthroscopy can also confirm that the meniscus is actually
missing. If the arthroscopy is performed elsewhere, information (photo prints
or video documents) should be available to the surgeon and correlated with
MRI findings.
MENISCAL ALLOGRAFT IMPLANTATION - SURGICAL TECHNIQUE
In case of meniscal allograft implantation surgery should be minimally invasive,
not sacrificing the original meniscal insertion points. It appears to be
preferable to use an open technique in medial transplantation, whereas
the arthroscopic approach appears to allow for easier lateral implantation.
Transplantation of the medial meniscus: Epidural anesthesia is induced and
a tourniquet is applied. The patient is placed supine, and a medial anterior
arthrotomy is performed. The possible meniscal remnant is resected down to
the meniscosynovial junction until a potentially bleeding surface is exposed.
Whether a standard medioposterior incision is made to facilitate transplantation
and further removal of the meniscal remnant, or an osteotomy of the medial
collateral ligament is performed, the meniscal can be inserted using 2.0
PDS sutures. In case of bone plug fixation, one should consider the increased
difficulty in regard to a more difficult technique and the increased risk
of improper placement of the bone plugs.
Transplantation of the lateral meniscus: Because of inherent increased varus
laxity versus valgus laxity, an arthroscopic technique is more indicated
in lateral meniscal transplantation.
The lateral meniscal allograft is prepared, whether associated with bone
plug fixation or meniscal wall suture or fixation, and the allograft is inserted
through a lateral arthroscopic portal, allowing easy passage through the
skin.
In case of an open approach, an extended lateral skin incision allows for
an osteotomy with bone plug of the lateral collateral ligament and popliteus
tendon insertion. This approach opens up the lateral compartment and makes
the implantation of the lateral meniscus from posterior to anterior possible.
Technique for tendon transplantation: Dieter Kohn described a modified medial
hockeystick incision, allowing to detach the medial collateral ligament with
a bone block. This allows medial opening of the knee joint and precise drill
hole preparation, allowing correct insertion of the tendon autograft. The
graft thickness should be at least 5 mm. This allows for correct graft fixation.
POSTOPERATIVE CONTROL AND REHABILITATION AFTER MENISCUS REPLACEMENT
Although no strict protocol could be advanced, based on the limited clinical
experience, the current protocols for postoperative rehabilitation should
follow parameters such as pain, effusion, locking and progressive gait
pattern. One could advocate accellerated rehabilitation based on successful
meniscal repair results.
In the early postoperative phase, with the use of prolonged epidural anaesthesia
continuous passive motion exercises are encouraged. It can be expected that
the patients can be discharged from the hospital at 8 days postoperatively.
Nonweightbearing should be implemented until day 21 p.o. Progressive weightbearing
is then allowed, as to obtain fullweightbearing by week 6.
Even though cycling and swimming promote rehabilitation in the early phase
of motion recruitment, return to noncontact sports is not allowed until the
4th month p.o. Contact sports are to be avoided until 12 months p.o.
VIABLE MENISCAL ALLOGRAFTS - CLINICAL RESULTS
A hundred and one implants are included in a study ranging from January 1989
to December 1999. Thirty-six patients had a transplantation of the medial
meniscus and 59 of the lateral meniscus. Three patients underwent bilateral
replacement (lateral and medial). The mean age at time of surgery was 34
years 5 months.
Although in 36 cases meniscal transplantation was performed as a solitary
procedure, it was combined with a valgus osteotomy in 13 cases and with an
intra-articular reconstruction of the anterior cruciate ligament using a
tendon allograft in 3 patients. A lateral meniscal transplantation was combined
with a supracondylar femoral varus osteotomy in 1 patient. Two valgus osteotomies
were associated with lateral meniscal implantation as was 1 ACL reconstruction
in another case.
Thirty-eight % of the patients went back to their original professional activities,
which had had to be stopped because of the pain and debilitating effect of
the meniscectomy performed before.
The HSS-score was arbitrarily devided in excellent (more than 175 points),
good to average (between 100 and 175 points) and poor (below 100 points).
At the mean follow-up of 5 years and 10 months 74 % of the patients remained
above the 175 points bracket. Twenty-six % dropped between 100 and 175 points.
None were rated below 100 points on the HSS score. Six total knee arthroplasties
are excluded in this evaluation.
There was a significant difference between pre- and postoperative pain evaluation
(n = 51; p < 0.001). There was no significant difference in statistical
evaluation of the HSS-score after medial transplants versus medial transplants
in association with a valgus osteotomy nor between lateral meniscal transplants
versus medial meniscal transplants in association with valgus osteotomy.
However, when referring to purely medial versus lateral transplantation,
pain relief was more pertinent ( p = 0.029) in case of lateral transplantation.
MRI evaluation was performed 103 times in 34 patients with 39 allografts
from 2 to 73 months postoperatively. There appeared to be a satisfactory
correlation between MRI and arthroscopic findings, but the relation to the
HSS-score was poor.
DNA fingerprinting of the cells cultured from the harvested material in 23
patients showed matching in 8 patients, nonmatching in 3 and both matching
and nonmatching cells in 4 patients. In 8 patients the biopsy did not contain
enough cells, even after culture, to perform correct DNA fingerprinting.
These results suggest that at a 2-year follow-up ingrowth had occurred in
the meniscal transplant, while some donor cells were still surviving, suggesting
biochemical activity in the meniscal transplant from the first day of transplantation.
We do not yet know whether the long-term survival of donor cells, with the
slow ingrowth of host cells into the transplanted meniscus, will have any
effect on the long-term functional results.
NORMAL VS. TRANSPLANTED MENISCI: EVALUATION OF EXTRUSION USING MRI AND US.
A PRELIMINARY REPORT.
Verdonk P, Depaepe Y, Desmyter S, De Muynck M, Almqvist F, Verdonk R. Department
of Orthopaedic Surgery and Rehabilitation, University Hospital Ghent, Belgium
This study investigates to what extent menisci extrude between femur and
tibia in the weightbearing position. A comparison is made between healthy
and transplanted menisci.
Aim of the study: To develop a clinically useful and reproducible method
to evaluate and to compare lateral meniscal extrusion in normal and transplanted
knees. We also hope to establish a correlation between extrusion and clinical
outcome.
Method: Two imaging techniques were used: magnetic resonance imaging and
ultrasonography. MRI images of 10 normal knee and 17 laterally transplanted
knee were analysed, both medial and lateral compartments. Extrusion was defined
as the distance measured from femoral condyl to the outer edge of the meniscus.
These measurements were done using MRI written software. Ultrasonographic
print-outs were analysed of 10 laterally transplanted knees and 10 normal
knees. Extrusion was defined in 2 way: extrusion surface was defined as the
surface measured outside the knee, extrusion distance was measured as the
greatest distance from a line connecting femur and tibia to the outer edge
of the meniscus. Patients were evaluated in the supine position, bipodal
stance and unipodal stance.
Results: A. MRI Results: The lateral transplanted meniscus is statistically
(p<0,005) more extruded than the normal lateral meniscus. The anterior
horn of the transplanted meniscus tends to be more extruded than the posterior
horn. The normal meniscus shows no extrusion. B. US Results: The lateral
transplanted meniscus is statistically (p<0,005) more extruded than the
normal lateral meniscus in all patient positions. Both surface and distance
are equally good parameters to determine meniscal extrusion. There is no
statistical difference between patient positions.
Discussion: The lateral meniscal implant is more extruded than the normal
meniscus measured by MRI and ultrasonography. Correlation between meniscal
extrusion and clinical results remains to be determined.
BIOCHEMICAL, BIOMECHANICAL, HISTOLOGIC, AND RADIOGRAPHIC INDICES OF ARTHRITIS
IN AN OVINE POST-MENISCECTOMY MODEL
+*Kelly, BT; *Potter HG; *Pearle, AD; *Nofsinger CC; *Deng X; **Kraus VB;
***Trumble TN; ***Billinghurst RC; ***Turner AS; *Warren, RF; *Rodeo SA
+*Hospital for Special Surgery, NY, NY, **Duke University Medical Center,
Durham, NC, ***Colorado State University, Fort Collins, CO
| INTRODUCTION: Preservation or repair of damaged
menisci is not always possible, and meniscal transplantation into knees
of patients with previous meniscectomies or irreparable damage has become
a means to protect the knee from progressive joint degeneration. The
long-term surgical results of this operative intervention have not been
well established, nor has the optimal timing for surgical transplantation
been defined. It has become evident, however, that meniscal transplantation
must be performed prior to the development of advanced joint degeneration.
The results of this procedure are sub-optimal if transplantation is delayed
until advanced radiographic changes are present. Thus, it is imperative
to develop a tool to allow early identification of articular degeneration,
in order to recommend reconstructive procedures in a timely fashion.
The purposes of this project were to: 1. implement and evaluate the accuracy
and reliability of various molecular markers for the quantification of
early articular cartilage damage in an ovine post-meniscectomy degenerative
knee model; and 2. correlate the molecular marker data with traditional
outcome measures including biomechanical testing, gross inspection with
india ink stain, histology, plain radiographs, and magnetic resonance
(MR) imaging. The primary hypothesis was that changes in biochemical
markers of cartilage destruction and joint homeostasis occur after total
lateral meniscectomy in the sheep knee, and that these changes correlate
with degeneration assessed by biomechanical testing, histologic criteria,
and imaging studies. METHODS: After IACUC approval was obtained, total lateral meniscectomies were performed on twelve skeletally mature Columbian X Rambouillet ewes and four control animals underwent a sham operation consisting of takedown and repair of the lateral collateral ligament. Serum was collected prior to the initial surgical procedure, every three days for the first two weeks post-surgery, and every two weeks thereafter until sacrifice. Synovial fluid was collected prior to the initial surgical procedure and every two weeks until sacrifice. Six meniscectomy animals and two sham operation animals were sacrificed at four months, and the remaining animals were sacrificed at two months. The markers that were studied included: synovial fluid and serum levels of keratan sulfate (KS)-5D4, COL2-3/4Cshort and COL2CEQ collagen degradation products; and serum levels of bone alkaline phosphatase (BAP). ELISA tests were performed on all fluid samples in order to quantify the biomarker levels at each collection period and to correlate the molecular marker data with traditional outcome measures. After sacrifice, all knee joints were assessed by cartilage biomechanical testing (Artscan), gross inspection, histology, plain radiographs, and MR imaging. ESSENTIAL RESULTS: Biochemical Testing: Serum BAP demonstrated a significant decrease from baseline levels between 5 and 14 days (p<0.05), followed by a gradual and continual rise to above baseline levels at two months. Synovial fluid levels of KS-5D4 from the operated side showed an early peak between two and four weeks with a slow but continual rise up to the limit of the study period. In contrast, the non-operated side did not show an early peak nor a continual rise. Synovial fluid levels of the COL2-3/4Cshort marker was significantly greater on the operated side compared to the non-operated side throughout the study period (p=0.04). As with the KS-5D4, the data demonstrated a bimodal distribution with an early and late peak, however, the non-operated side also appeared to have a bimodal distribution. Preliminary data suggest that the marker levels on the operated side may peak earlier than the non-operated side. Biomechanical Testing: Biomechanical testing of four month meniscectomy knees demonstrated significantly decreased articular cartilage stiffness over the lateral tibial plateau compared to controls (p=0.005). At two months stiffness was significantly decreased over the anterior, lateral tibial plateau only compared to controls (p=0.02). Gross Inspection: All knees were dissected and disarticulated. India ink staining was performed and the stain area was calculated. The average stain area overlying the lateral tibial plateau was significantly greater (p<0.05) on the meniscectomy knee compared to the non-operated side (69.68 mm2 versus 12.43 mm2) |
MRI: MR imaging quantitatively evaluated cartilage wear, bone sclerosis, sub-chondral edema, and osteophyte formation. Spin echo T2 relaxation maps of the tibia were processed. MR imaging demonstrated severe joint degeneration four months post-meniscectomy. At two months joint degeneration was present, but significantly less than at four months (p=.05). MR data correlated with biomechanical data (r=-.7). Both MR and biomechanical findings correlated with gross inspection.
|
Fig.
2: Meniscectomy Knee
A CLINICAL AND OBJECTIVE EVALUATION OF MENISCUS ALLOGRAFT TRANSPLANTATION
AT MINIMUM TWO-YEAR FOLLOW-UP
Scott A. Rodeo MD, Hollis G. Potter MD, Mario Berkowitz MD, Peter Sultan
MD, Thomas L. Wickiewicz MD, and Russell F. Warren MD
Sports Medicine and
Shoulder Service, The Hospital for Special Surgery
Background: Despite early reports of clinical improvement following meniscus
allograft transplantation, very few studies have directly evaluated the transplanted
meniscus. Since many meniscus transplants are performed with other concomitant
procedures, it is important to objectively evaluate healing and survival
of the meniscus allograft. The purpose of this study is to test the hypothesis
that the clinical outcome of meniscus transplantation is related to degree
of arthrosis and flattening of the femoral condyle, based on objective assessment
measures.
Methods: We evaluated 36 patients with 42 fresh-frozen, non-irradiated meniscal
transplants using magnetic resonance imaging (MRI), physical examination,
and standardized outcome scales at a mean of 56 months following surgery.
A "Meniscus Score" (0-15) was derived for each transplanted meniscus
by grading the MRI for intra-meniscal signal intensity, position relative
to the tibial plateau, size, morphology, and healing to the capsule. Transplants
were graded as good (0-4), fair (5-7), or failed (>8). Remodeling (flattening)
of the femoral condyle was graded on MRI. The thickness, size, and location
of hyaline cartilage lesions were used to derive a "Cartilage Score" (0-100,
a measure of arthrosis). Correlations were made between the Meniscus Score,
Cartilage Score, condylar flattening, alignment, and scores on the outcome
scales.
Results: Based on our objective evaluation, 17 transplants were graded as
good, 12 as fair, and 13 as failed. There were significant improvements on
Lysholm II, I.K.D.C., and visual analog scale pain and function scores. Our
hypothesis was affirmed: there was a significant correlation between the
Meniscus Score and the Cartilage Score (r2=-.32, p=.04), demonstrating a
worse outcome for meniscus transplants with more advanced arthrosis. The
Meniscus Score also correlated with the degree of flattening of the femoral
condyle (r2=.45, p=.003), with worse outcomes associated with greater flattening
of the condyle. There was a strong correlation between the Meniscus Score
and the degree of extrusion (r2=.83, p<.001), and the amount of extrusion
was greatest in knees with the greatest degree of flattening of the condyle
(r2=.41, p=.009). Transplants performed with a common bone slot connecting
the anterior and posterior meniscal horns had a significantly better outcome
than menisci implanted with free bone plugs (p=.036).
Conclusions: We found that the outcome of meniscus transplantation was directly
related to the degree of arthrosis and flattening of the femoral condyle,
as assessed by MRI. The best results were found in transplants where the
native horn attachments were preserved. Meniscus transplantation should be
performed prior to the development of advanced arthrosis and condylar remodelling,
both of which may be assessed on a preoperative MR examination.
MENISCAL ALLOGRAFTS IN PATIENTS WITH SEVERE ARTHROSIS
Kevin R. Stone, M.D.*, Ann Walgenbach, R.N.N.P*,
Ronald LaVallee, MPH, PA-C†,
and Thomas Turek‡
*Stone Clinic, San Francisco, CA, † The Stone Foundation for Sports
Medicine and Arthritis Research, San Francisco, CA ‡ Cross Cart, Inc.
San Francisco, CA.
OBJECTIVE: Can meniscus allografting survive in the setting of knee arthritis?
Previous clinical reviews stated that allografting was contraindicated in
patients with arthritis and past the age of 50. We studied the effect of
age and arthritis on the survival of meniscal allografts in the hope of discovering
that the technique might have usefulness for those patients trying to delay
arthroplasty. We present the findings of 46 meniscus allograft patients (48
allografts) with grade IV arthritis with a minimum of 2 years from surgery,
mean age of 50 years (range 14-69) and with 25% over the age of 58 years.
METHODS: Prospective data was collected for 46 consecutive patients (two
patients had bilateral grafts) with pre-operative x-ray, MRI, arthroscopic
and clinical evidence of loss of the meniscus and grade IV arthritis with
informed consent. The surgical technique used was the "three tunnel
technique" previously described by the senior author. Serial clinical
exams, x-ray, MRI and questionnaires for pain, activity, and function were
used. No patient was lost to follow up. Graft failure was defined as surgical
removal of the allograft. Statistical analysis included paired t-tests and
Kaplan-Meir survival curves. Power analysis with a delta of 0.1, sigma of
0.18, an alpha of 0.05, and N=35 demonstrates a power of 0.89.
RESULTS: Statistically significant (p<0.05) improvement occurred in the
mean pre-operative pain score, the mean activity score, and the mean function
score independent of age, joint space narrowing, or severe malalignment.
Twelve of 48 menisci required a second arthroscopy for either suture repair
or partial meniscectomy. Using a Kaplan-Meier analysis the mean time to failure
adjusting for censoring was 4.3 years. The overall failure rate was 6/48
or 13%.
CONCLUSIONS: Our study demonstrates that the previous contraindication of
age and severity of arthrosis is overstated. We found that our results compare
favorably with previous reports of patients who were younger and with less
severe degenerative disease. Meniscal allografts survive moderately well
in knees with arthritis. The role that they play however is difficult to
parse from the benefit of the concomitant procedures performed during arthroscopy
of arthritic knees.
ROLE OF MENISCUS ALLOGRAFTS ALONE AND COMBINED WITH ACL RECONSTRUCTION OR
OSTEOCHONDRAL AUTOGRAFT TRANSFER PROCEDURES
Frank R. Noyes, M.D. and Sue D. Barber-Westin, B.S. Cincinnati Sportsmedicine
and Orthopaedic Center, Cincinnati, OH
Background: The purpose of this study was to report on
our experience with meniscal transplantation by prospectively following a
consecutive group of patients a minimum of two years postoperatively. We
rigorously assessed outcome using tibiofemoral compartment pain or clinical
signs of transplant tearing, follow-up arthroscopy, and magnetic resonance
imaging (MRI) to determine meniscus allograft failure rates. We are not aware
of any study that used weightbearing MRI to determine meniscus allograft
displacement, deformation, position and motion compared to normal menisci,
or that determined the outcome of knees that had an associated osteochondral
autograft transfer (OAT) with the meniscus transplant.
Methods: Between November 1995 and March 2000, 38 patients
were treated with 40 cryopreserved meniscal allografts at our institution.
Four allografts in three patients were removed before 2 years postoperative.
This left 35 patients with 36 meniscus allografts who were followed (100%
follow-up) a mean of 3.3 years (range, 2 to 6.9 years) postoperatively. The
mean age at surgery was 30 years (range, 14 to 49 years). In 14 knees, an
associated OAT procedure was done for a full-thickness femoral condylar defect
and in 8 knees, an associated ligament reconstruction was performed. MRI
was used to evaluate 29 of the 36 (81%) meniscus allografts under weightbearing
conditions an average of 34 months (range, 12 to 66 months) post-implantation.
Results: Statistically significant improvements were found
postoperatively for pain with activity, pain severity, and tibiofemoral compartment
pain at the meniscus transplant site. At follow-up, 94% of the patients rated
their knee condition as improved compared to the preoperative condition.
Pain in the meniscectomized tibiofemoral compartment was alleviated in 71%
and reduced to mild in 11% even though articular cartilage degeneration or
bone exposure was found in the meniscectomized tibiofemoral compartments
in 88% of the knees. The overall classification of the meniscus allografts
(MRI, clinical joint pain and signs of meniscus tears, and follow-up arthroscopy)
showed 18 (45%) with normal characteristics, 13 (33%) with altered characteristics
(MRI increased signal intensity, mild pain), and 9 (22%) failed. Concomitant
OAT procedures and knee ligament reconstructions did not effect meniscus
allograft characteristics, functional or symptom results, or postoperative
complications.
Conclusions: The data showed that meniscus transplantation
is an acceptable short-term procedure for select patients, as it produced
a marked decrease in pain in the meniscectomized compartment and improved
knee function. Patients with femoral condylar defects treated with an associated
OAT procedure also had significant improvements in pain and function. The
long-term function of the meniscus transplant remains questionable. The transplant
undergoes incomplete remodeling resulting in alterations in meniscus fibrous
micro-architecture and matrix required for load-sharing and long-term survival.
The chondroprotective effect of the meniscus transplant remains unknown.
LONG TERM (FIVE TO SIX YEARS) FOLLOW-UP OF COLLAGEN MENISCUS IMPLANTS USED
TO RECONSTRUCT THE INJURED MEDIAL MENISCUS: A PROSPECTIVE CLINICAL STUDY
William G. Rodkey, D.V.M.
PURPOSE: We conducted 5 to 6-year follow-up on eight patients who underwent
reconstruction of one injured medial meniscus with a collagen meniscus implant.
We hypothesized that, based on standardized pain and functional assessment
scores, these patients would demonstrate significant clinical improvement
over their preoperative status and would have maintained their status determined
at the 2-year follow-up.
METHODS: Eight patients underwent arthroscopic placement of a collagen meniscus
implant to reconstruct the damaged medial meniscus of one knee between December
1995 and July 1996. Patients initially were followed for two years clinically,
with imaging, and relook arthroscopy at 6 or 12 months with biopsy. For the
present study, all patients returned an average 5.8 years (range, 5.5 to
6.3 years) after collagen meniscus implant placement. Patients underwent
clinical, radiographic, magnetic resonance imaging, and arthroscopic examinations.
Pain, Lysholm, Tegner and self-assessment scores were determined and compared
to scores at time of implantation and two years afterward.
RESULTS: Lysholm scores improved significantly (p=0.045) from 75 preoperatively
(range, 52 to 97) to 88 at final follow-up (range, 74 to 95). Tegner activity
scores improved significantly (p=0.001) from 3 (range, 1 to 5) to 6 (range,
4 to 8) at these time points. Patient self-assessment improved significantly
(p=0.046) from 2.4 to 1.9 (1=normal, 4=severely abnormal). Pain scores improved
from 23 to 11 (0=no pain, 100=worst pain). Imaging studies confirmed the
chondral surfaces appeared protected from further degeneration, and the new
tissue became indistinguishable from native meniscus. The tissue appeared
stable and virtually unchanged since the initial relook.
CONCLUSIONS: The meniscus-like tissue that developed after collagen meniscus
implant placement maintained its structure and functioned similar to native
meniscus for more than five years. We affirmed our hypothesis that these
patients were significantly improved compared to their preoperative status
and unchanged compared to two years.
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