Abstract The menisci provide a vi-tal role in load transmission acrossthe knee joint as well as contribute toknee stability, particularly in the ACL-deficient knee. Loss of the meniscus,in part or in total, significantly altersjoint function and predisposes the ar-ticular cartilage to degenerativechanges, which has been well docu-mented both clinically and radiograph-ically. This study examined clinicaland patient-reported outcomes follow-ing meniscal allograft transplantationwith and without combined ACL re-construction in a select group of 31 patients with complaints of painand/or instability (34 meniscal allo-grafts); 11 underwent isolated menis-cal transplantation and 20 meniscaltransplantation combined with ACLreconstruction. Bony fixation wasperformed with bone plugs for medialtransplants and using a bone bridgefor lateral transplants. All patientscompleted several knee-specific andgeneral measures of health-relatedquality of life and underwent a com-prehensive physical examination.Flexion weightbearing PA radiographsat latest follow-up were compared tothose obtained preoperatively. Meanfollow-up was 2.9 years (range 2–5.5 years). The Activities of DailyLiving and Sports Activities Scalescores were 86±11 and 78±16, re-spectively, and the average Lysholmscore was 84±14. There were no sig-nificant differences in these scoresbased upon which meniscus (medial

or lateral) was transplanted, concur-rent ACL reconstruction, or the degreeof chondrosis at arthroscopy. SF-36scores indicated that patients werefunctioning at a level similar to theage- and sex-matched population.Twenty-two patients stated they weregreatly improved, 8 were somewhatimproved, 1 was without change. Allbut one patient reported that kneefunction and level of activity werenormal or nearly normal. The averageloss of motion compared to the non-involved side was 3° for extensionand 9° for flexion. All but one patienthad a negative or 1+ Lachman’s test.The remaining patient had a 2+ Lach-man’s test. Assessment with the KT-1000 arthrometer revealed a side-to-side difference of 2 mm (range –2 mm to 7 mm). Average hop andvertical jump indices were both 85%of the contralateral extremity. No sta-tistically significant joint space nar-rowing was observed by radiographyover time. Meniscal allograft trans-plantation with and without combinedACL reconstruction in carefully se-lected patients with complaints ofcompartmental joint line pain and/orinstability appears able to provide re-lief of symptoms and restore relativelyhigh levels of function, particularlyduring activities of daily living.

Keywords Meniscal allografts ·Transplantation · Meniscustransplantation · Meniscal surgery ·Meniscus

KNEEKnee Surg Sports Traumatol Arthrosc(2003) 11 : 173–182

DOI 10.1007/s00167-003-0362-y

Erol A. Yoldas Jon K. Sekiya James J. Irrgang Freddie H. Fu Christopher D. Harner

Arthroscopically assisted meniscalallograft transplantation with and without combined anterior cruciateligament reconstruction

Received: 12 October 2001 Accepted: 16 December 2002 Published online: 9 May 2003© Springer-Verlag 2003

E. A. YoldasHoly Cross Hospital Medical Group, 6000 N. Federal Highway, Ft. Lauderdale,FL 33308, USA

J. K. SekiyaBone and Joint/Sports Medicine Institute,Department of Orthopaedic Surgery,Naval Medical Center Portsmouth,Portsmouth, VA, USA

J. J. Irrgang · F. H. Fu · C. D. Harner (✉)Center for Sports Medicine, University of Pittsburgh Medical Center,3200 South Water Street, Pittsburgh, PA 15203, USATel.: +1-412-4323662, Fax: +1-412-4323690,e-mail: harnercd@msx.upmc.edu

Introduction

The role of the meniscus in load transmission and stabil-ity of the knee joint is well documented [14, 18, 27, 28, 29,44, 45, 52]. The menisci have been found to transmit up to60% of the load across the knee joint, with the lateralmeniscus playing a more important role in load transmis-sion than the medial meniscus [11, 25, 26, 42]. In the past,total or subtotal meniscectomy was routinely performed forpatients with meniscal tears. The usual sequela of such pro-cedures is the onset of degenerative arthritis over time, in-cluding narrowing of the joint space, flattening of the fem-oral condyles, and formation of osteophytes [2, 3, 11, 19,47].

In recent years most orthopedic surgeons have recog-nized the biomechanical and morphological importance ofthe meniscus and advocated its preservation. Meniscal re-pair has become the accepted treatment for meniscal tears,and if the meniscus is not repairable, arthroscopic partialmeniscectomy of only the torn portions of meniscus is rec-ommended [8, 9, 10]. Unfortunately in some cases nearlythe entire meniscus is torn and irreparable, requiring subto-tal or complete meniscectomy which leads to a predictablepattern of progressive deterioration of the articular carti-lage and radiographic joint space narrowing [2, 3, 11, 25,47]. Management of the meniscus-deficient knee is verydifficult, particularly in young active patients and in pa-tients with anterior cruciate ligament (ACL) deficiency.

Meniscal allograft transplantation has gained interestin recent years and has become a viable option for treatingthis very difficult patient population. Our interest in thisprocedure is based on both our experience and that of oth-ers with allograft ligament reconstruction [16, 17, 19, 22,34, 41] and on studies of meniscal allograft transplanta-tion in animals [4, 7, 21, 56] and in humans [5, 6, 15, 23,24, 32, 33, 37, 46, 49, 50, 51].

The purpose of this study was to determine the clinicaland patient-reported outcomes following meniscal allo-graft transplantation with and without ACL reconstructionin carefully selected patients with a minimum follow-upof 2 years. Our hypothesis was that following this proce-dure patients would have satisfactory overall knee functionand relief of symptoms, and that the meniscal allograftwould provide protection for the transplanted compart-ment’s chondral surfaces, as seen by delayed radiographicjoint space narrowing. A secondary goal of the study wasto determine whether stability can be reliably restored withACL reconstruction in patients with a combined ACL andmeniscus-deficient knee.

Materials and methods

Between 1993 and 1996 we performed 38 meniscal allograft trans-plants in 35 patients. Of these, 31 patients with 34 allografts couldbe located for follow-up. The average duration of follow-up was2.9 years (range 2.0–5.5 years). There were 18 men and 13 women

with an average age of 28 years (range 15–42) at the time of surgery.Patients averaged 2.4 surgical procedures (range 1–4) prior totransplantation. The average interval between the initial meniscec-tomy and transplantation was 8 years (range 10 months–28 years).Eleven patients underwent isolated meniscal transplantation; thelateral meniscus was implanted in 9 and the medial meniscus wasimplanted in 2. Of the 20 remaining patients, 12 underwent con-comitant primary ACL reconstruction with patellar tendon auto-graft, and 8 underwent revision ACL reconstruction using patellartendon allograft. Of the patients undergoing concomitant ACL re-construction 3 had the lateral meniscus implanted, 14 had the me-dial meniscus implanted, and 3 had both menisci transplanted. Themean follow-up period was 2.9 years (range 2.0–5.5).

Indications for meniscal transplantation

Essential to the success of meniscal allograft surgery is identifyingthe appropriate patient via history, physical examination, andimaging techniques including radiographs and magnetic resonanceimaging (MRI) [6, 15, 23, 32, 33, 49, 50]. The criteria that we usedto select patients for meniscal transplantation included pain, age,status of articular cartilage, joint stability, and mechanical align-ment. Although there are no formal age limitations, “younger” in-dividuals who had prior meniscectomies with joint line pain duringactivities of daily living (ADL) and/or sports were considered can-didates for this procedure. Patients with instability secondary toACL injury or a failed ACL reconstruction were also consideredpotential candidates if they also had a prior menisectomy with jointline pain during activity. Because the meniscus has both load dis-tribution and stabilizing functions, we felt that this group of patientswas especially worth considering for combined meniscal transplan-tation and ACL reconstruction.

To estimate the status of the articular cartilage preoperativelywe obtained posterior-anterior (PA) 45° flexion weight-bearing andlong cassette radiographs. If there was joint space narrowing greaterthan 2 mm on either film, the patient was not considered an appro-priate candidate for meniscal transplantation due to advanced degen-erative changes based on criteria established by Rosenberg et al.[40]. In certain instances we could not completely assess the statusof the articular cartilage and had to defer our assessment until di-agnostic arthroscopy. In general most patients had Outerbridge [36]grade II and small areas of grade III chondrosis. Larger areas ofgrade III changes and any grade IV chondrosis were consideredcontraindications to meniscal transplantation. (In the patients witha large area of grade IV chondrosis a combined osteochondral al-lograft and meniscal allograft transplantation was performed.) Thesepatients were not included in this study.

Of the 16 patients receiving a medial meniscus, 7 had grade Ior II chondrosis, and 9 had small, focal (less than 2 cm) grade IIIchondrosis. Of the 12 patients undergoing lateral meniscus trans-plantation, 6 had grade II and 6 had focal grade III chondrosis.There were 3 patients with both medial and lateral meniscal allo-grafts: 2 with grade II and 1 with focal grade III chondrosis. Insummary, of the 31 patients 15 (48%) had grade I or II chondrosis,and 16 (52%) had small, focal areas of grade III chondrosis.

In addition, the mechanical axis was determined using the longcassette films. Asymmetry of greater than 2° from side to side in-volving the meniscus-deficient compartment was considered a con-traindication to meniscal transplantation. A staged realignment os-teotomy was performed prior to meniscal transplantation. Thesepatients were not included in this study.

Donor/recipient matching

Both biological and mechanical factors are involved in the suc-cessful incorporation of the meniscus allograft [4, 14, 33, 37]. Nu-merous animal and human studies have shown that transplanted

174

menisci do heal, especially at the peripheral rim [5, 6, 15, 21, 32,49, 50, 51]. Correct sizing of the meniscal allograft is critical forhealing. Prior to undertaking meniscal transplantation we studieddonor and recipient sizing [24] (Fig. 1). This work enabled us todevelop simple and accurate criteria to size the donor and recipientmeniscus based upon preoperative lateral and PA radiographs. Ourmeasurements were matched with measurements made by techni-cians at the tissue bank to select an appropriately sized graft. Cor-rect sizing of the meniscal allograft requires selection of an isotropicgraft (i.e., a graft matched for the right or left knee and for the me-dial or lateral compartment) as well as the consideration of subchon-dral bone length on lateral and PA radiographs after correction formagnification (Fig. 2). This technique is similar to that describedby Pollard et al. [38]. All tissues were sterilely harvested and frozenat –80° C. None of our meniscal allografts were irradiated. Appro-priate screening using the American Association of Tissue Bankstandards was performed for all grafts.

Surgical technique

An examination under anesthesia was performed in all cases todocument knee instability (if present) and range of motion. Ar-throscopy was then performed and the ACL deficiency (if present)was confirmed and the degree of meniscus deficiency and the con-dition of the articular cartilage were assessed in the involved com-partment. If the knee was appropriate for isolated meniscal trans-plantation or combined meniscal transplantation and ACL recon-struction, the allografts were thawed and reconstituted accordingto standard protocol.

The body of the native meniscus was trimmed to provide afresh bleeding surface for the meniscal allograft to be repaired to. Itwas our goal to preserve as much of the peripheral one third of thenative meniscus as possible for attachment of the allograft. If acombined ACL reconstruction was indicated, standard femoral andtibial tunnels were then drilled and prepared for our ACL graft. Asmall medial or lateral parapatellar arthrotomy was utilized forgraft passage and open suture fixation of the anterior aspect of themeniscal allograft. The anterior horn of the native meniscus wastrimmed to a fresh, bleeding rim. Either a posterolateral or postero-

medial approach to the knee was performed to expose the joint linefor later meniscus repair. For medial meniscal transplantation aposteromedial arthrotomy was also performed between the super-ficial MCL and the posterior oblique ligament, and this was used forboth meniscal allograft passage and posterior capsule suture fixation.

For the medial meniscus transplant we fixed the anterior andposterior horns using bone plugs passed through transosseous tun-nels (Fig. 3). For our lateral meniscal transplant a trough was cre-ated in the lateral tibial plateau, and the bone bridge attached to theanterior and posterior horns was fixed into the trough using tran-sosseous suture fixation (Fig. 4). Three patients prior to 1994 un-derwent a lateral meniscus transplant with bone plugs. The anteriorhorn of the transplanted meniscus was then sutured to the nativemeniscus using #0 braided, nonabsorbable sutures through thearthrotomy. For our medial meniscus transplant the posterior hornwas secured to the posterior capsule with #2 braided, nonabsorbablesutures passed through the posteromedial arthrotomy. The remain-ing meniscal allograft (medial or lateral) was then secured usingarthroscopic inside-out techniques with 2–0 nonabsorable sutures.

A standard ACL reconstruction was then performed (in casesof ACL deficiency), with the femoral and tibial bone plugs of thepatellar tendon allograft secured with metal interference screws us-ing an endoscopically assisted technique. In the revision ACL casesa determination was made regarding tunnel position, hardware ac-cess, and bone quality. Depending upon the individual cases, hard-ware was removed either during the index procedure or in a stagedfashion with bone grafting of the tunnels. All wounds were copi-ously irrigated with antibiotic solution and closed in a standardfashion. The patient was placed in a compression dressing with acontinuous cooling device, and a hinged-knee brace locked in ex-tension.

Postoperative management

Postoperatively all the patients had a similar rehabilitation pro-gram [13]. Immediately after surgery patients began quadricepssets and straight leg raises. Twenty-four hours after surgery pas-sive range of motion using a continuous passive motion machine

175

Fig. 1 Diagram of an axial view of a right tibial plateau, showingthe meniscal horn insertions. AL, PL Anterior, posterior horns of lat-eral meniscus; AM, PM anterior, posterior horns of medial menis-cus. Note the intimate association of the lateral meniscal horn in-sertions with that of the ACL and also their close proximity to oneanother

Fig. 2 Lateral radiograph of cadaveric knee showing the subchon-dral bone lines, which are correlated with the size of the meniscus:open arrows medial meniscus; closed arrows lateral meniscus

was started and was continued for 1 month. The goals for range ofmotion were to achieve full extension symmetrical to the nonin-volved side within 1 week and 90° of flexion within 4–6 weeks.Immediately after surgery patients were restricted to partial weight-bearing with crutches with the brace locked in full extension. After1 week the patient was advanced to weight bearing as tolerated.Crutches were discontinued 4–6 weeks after surgery provided thepatient had full knee extension without a quadriceps lag, 90–100°of knee flexion, absent or minimal swelling, and was able to walkwithout a bent knee gait. Rehabilitation was continued for 2–3 months with an emphasis on restoring full motion and strength.Closed chain exercises were initiated 6 weeks after surgery from0° to 45° and were gradually progressed to 75° of flexion. Low-impact aerobic activities (walking, cycling, swimming) were initi-ated after 8 weeks. Patients returned to sedentary work after 1 weekand to strenuous work after 3–4 months. Patients were allowed toreturn to running after 4–5 months and to light and moderate sportsafter 6–9 months. Return to strenuous sports was not recommended.

Follow-up examination

Thirty-one patients returned for follow-up. At that time physicaland radiographic examinations were performed, and patients com-pleted several questionnaires containing specific and general mea-sures of health status. Specific measures of health status included

the Lysholm Knee Score [48] and Knee Outcome Survey [20]. TheMedical Outcomes Study Short-Form 36-item questionnaire (SF-36)[30, 31, 53] was used as a measure of general health status.

The Lysholm Knee Score is a measure of symptoms and func-tional limitations that was originally developed for ACL injuriesbut has subsequently been applied to individuals with a variety ofknee problems including meniscal allograft transplantation [55].The Lysholm Knee Score ranges from 0 to 100 points and is inter-preted as: excellent, higher than 94; good, 84–94; fair 65–83; andpoor, less than 65 points [48].

The Knee Outcome Survey is a knee-specific measure of symp-toms and functional limitations that has been developed for indi-viduals with a variety of knee problems including meniscal injuries.The Knee Outcome Survey consists of two separate scales. TheActivities of Daily Living Scale (ADLS) includes items related tosymptoms and functional limitations experienced during ADL andthe Sports Activity Scale (SAS) consists of items related to symp-toms and functional limitations commonly experienced during sportsactivities. Each scale is scored from 0 to 100, with 100 represent-ing the absence of symptoms and higher levels of function.

The SF-36 is a general health status measure that is applicableto diverse populations of individuals with a variety of conditions.The SF-36 consists of eight scales including physical function, rolelimitations due to physical problems, bodily pain, general health,vitality, social functioning, role limitations due to emotional prob-lems and mental health. The eight scale scores can be combined intophysical and mental components summary scores. The SF-36 hasbeen used to measure general health status for a variety of ortho-pedic conditions, including anterior cruciate ligament reconstruc-tion [12, 35, 43, 54] and meniscus transplantation [39].

176

Fig. 4 Drawing of the lateral meniscal allograft being inserted us-ing a bone bridge technique

Fig. 3 Drawing of the medial meniscal allograft being transplantedusing the bone plug technique

The follow-up examination was conducted by a physical thera-pist and a physician who was not involved in performing the sur-gery and included an assessment of swelling, crepitus, range of mo-tion, stability, and functional strength. Crepitus of the anterior,medial and lateral compartments and swelling were graded by pal-pation as present or absent. Range of motion was measured with agoniometer and the side-to-side difference for extension and flex-ion was calculated.

The examination for laxity included the Lachman’s, pivot shift,posterior drawer, anterolateral rotatory, posterolateral rotatory andvarus/valgus stress tests. Laxity was graded relative to the contralat-eral side as normal (<2 mm side-to-side difference), nearly normal(3–5 mm side-to-side difference), abnormal (6–10 mm side-to-sidedifference) or severely abnormal (>10 mm side to side difference).All patients who had an ACL reconstruction underwent a 30-lb andmaximum manual KT-1000 test to assess anterior laxity of theknee. Both knees were tested and the side-to-side difference in an-terior laxity was calculated.

Functional strength was evaluated by having the patient per-form the single leg hop and vertical jump tests. Both lower ex-tremities were tested and the results were expressed as a percent-age of the noninvolved side.

Radiographs were obtained on the return visit and were com-pared to those obtained preoperatively. These included the PA 45°flexion weight bearing, lateral, merchant, and long cassette radio-graphs. The medial and lateral joint spaces of both knees weremeasured using a digital micrometer. This allowed for a compari-son of the joint space measurements over time with respect to thenoninvolved side. The joint space measurements were performedtwice by blinded observers to reduce intraobserver errors.

Data management and analysis

Descriptive statistics including frequencies and mean values werecalculated for all variables. One-way analysis of variance was per-formed to determine the effect of isolated meniscal transplantationor transplantation combined with concomitant ACL reconstructionon the outcome measures. A dependent t test was used to evaluatethe radiographic changes in joint space from before surgery to lat-est follow-up.

Results

Subjective results

Patient-reported measures of health status

The knee-specific measures of health status by type ofmeniscus transplant (medial, lateral, or both) and ACL re-construction (primary or revision) are reported in Table 1and by type of meniscus transplant (medial, lateral, orboth) and degree of articular cartilage chondrosis (gradesI – III) in Table 2. In general, patients had higher levels offunction during ADL then during sports activities.

With the relatively small sample sizes we were unableto detect any significant differences in the ADLS, SAS, orLysholm scores by location of the transplanted meniscus(medial vs. lateral vs. combined medial and lateral), con-comitant ACL reconstruction (meniscus transplant withoutACL reconstruction vs. meniscal transplant with primaryACL reconstruction vs. meniscal transplant with revisionACL reconstruction), or degree of chondrosis (grades I

177

Table 1 Knee-specific measures of function by meniscus trans-plant and ACL reconstruction status (ADLS Activities of DailyLiving Scale of Knee Outcome Survey, SAS Sports ActivitiesScale of Knee Outcome Survey, Lysholm Lysholm Knee Score,ACLR anterior cruciate ligament reconstruction)

ADLS SAS Lysholm

MedialNo ACLR (n=2) 79.4±11.5 73.0±26.9 73.5±2.1 Primary ACL (n=9) 92.1±3.4 82.7±17.0 89.4±8.9 Revision ACL (n=5) 84.5±7.1 68.8±19.5 74.0±19.1 Total (n=16) 88.1±7.2 77.1±18.7 82.6±14.3

LateralNo ACLR (n=9) 81.5±14.1 78.7±14.8 83.6±16.70 Primary ACL (n=1) 92.5 76.0 95.0 Revision ACL (n=2) 93.8±3.5 78.0±14.1 93.0±2.8 Total (n=12) 84.5±13.2 78.3±13.3 86.1±15.0

Medial and lateralNo ACLR (n=0)Primary ACL (n=2) 92.5±1.8 89.0±9.9 90.5±6.4 Revision ACL (n=1) 58.8 60.0 79.0 Total (n=3) 81.3±19.5 79.3±18.2 86.7±8.0

TotalNo ACLR (n=11) 81.1±19.5 77.6±15.9 81.7±15.5 Primary ACL (n=12) 92.2±2.9 83.2±15.2 90.1±8.0 Revision (n=8) 83.6±12.2 70.0±n=16.7 79.4±16.9 Total (n=31) 86.1±11.0 77.8±16.2 84.4±13.9

Table 2 Knee-specific measures of function by meniscus trans-plant and chondrosis of articular surface (ADLS Activities of DailyLiving Scale of Knee Outcome Survey, SAS Sports Activities Scaleof Knee Outcome Survey, Lysholm Lysholm Knee Score, grade Iarticular cartilage softening, grade II chondral fissures and fibrilla-tion, grade III extensive chondral fibrillation with crabmeat changes[36])

ADLS SAS Lysholm

MedialGrade I (n=2) 90.6±6.2 86.0±19.8 80.0±26.9 Grade II (n=5) 88.3±9.8 81.6±24.4 81.8±21.8 Grade III (n=9) 87.5±6.6 72.7±15.8 83.7±7.2 Total (n=16) 88.1±7.2 77.1±15.8 82.6±14.3

LateralGrade I (n=0) Grade II (n=6) 82.7±17.9 73.0±15.8 80.7±20.1 Grade III (n=6) 86.3±7.6 83.7±8.6 91.5±4.5 Total (n=12) 84.5±13.2 78.3±13.3 86.1±15.0

Medial and lateralGrade I (n=0) Grade II (n=2) 92.5±1.8 89.0±9.9 90.5±6.4 Grade III (n=1) 58.8 60.0 79.0 Total (n=3) 81.3±19.5 79.3±18.2 86.7±8.0

TotalGrade I (n=2) 90.6±6.2 86.0±19.8 80.0±26.9 Grade II (n=13) 86.4±13.4 78.8±18.7 82.6±18.5 Grade III (n=16) 85.2±9.6 76.0±14.4 86.3±7.3 Total (n=31) 86.1±11.0 77.8±16.2 84.4±13.9

and II chondrosis vs. small focal grade III chondrosis).The ADLS, SAS, and Lysholm Knee Scores in the threepatients who underwent lateral meniscus transplantationwith bone plugs prior to 1994 were slightly lower thanthose who underwent transplantation with bone bridgesafter 1994; however, the sample size was too small to con-firm this statistically.

Subjects also provided a subjective assessment of his/her knee function and current level of activity accordingto the 1993 International Knee Documentation Committee(IKDC) guidelines. In terms of function of the knee 11 pa-tients stated they were normal, 19 were nearly normal,and only 1 reported an abnormal level of function. In termsof current level of activity only 1 patient reported an ab-normal level of activity, 14 reported the level of activity tobe nearly normal, and 16 reported the level of activity tobe normal.

The SF-36 results are reported Table 3. To compare theSF-36 scores with age- and sex-matched population normsin the United States standard scores (i.e., Z scores) werecreated for each individual by subtracting the age- andsex-matched population average from the individual’sscore and then dividing by the age- and sex-matched pop-ulation standard deviation. As shown in Table 3, the scoreof –0.18 for physical function indicates that followingmeniscal transplantation individuals are on average 18%of a standard deviation below their age- and sex-matchedpopulation scores. Review of the eight aspects of the SF-36suggests that the patients are functioning physically, men-tally, and socially at high levels. In fact in seven of theeight categories the meniscal transplant patients scoredhigher than their age- and sex-matched population. How-ever, lack of preoperative SF-36 scores precludes us frombeing able to determine the change in health status as a re-sult of the meniscal transplantation.

The physical components summary score, which was53.3±6.7, supports these results. The physical componentssummary score is a transformed score that combines all 8 SF-36 scale scores into a single score that represents

physical function. In the United States population thisscore has a mean of 50 and standard deviation of 10, thusthe level of physical function in these patients was ap-proximately three-tenths of a standard deviation above theUnited States population average.

Symptoms

Relatively few patients had symptoms during ADL. Basedon the IKDC assessment of symptoms, 94% of the patientsdid not have pain during ADL, 97% did not have swelling,and no patients had instability during ADL. Fewer patientswere asymptomatic during moderate and strenuous sportsactivities. Sixty-one percent could participate in moderateor strenuous sports without pain, 58% could participatewithout swelling, and 74% could participate in these ac-tivities without instability.

Similar results were observed when the items in theLysholm Knee Scale related to pain and instability wereevaluated. Eighty-one percent had either none or onlyslight pain during severe exertion and 84% rarely or neverhad instability, even during strenuous activities.

There were no significant differences in symptomsbased upon which meniscus was transplanted. To deter-mine the effect of concomitant ACL reconstruction on in-stability following meniscal transplantation we comparedthe IKDC rating of instability and the instability questionfrom the Lysholm Knee Scale between those who did nothave a concomitant ACL reconstruction to those who un-derwent a concomitant primary ACL reconstruction andto those who underwent a concomitant revision ACL re-construction. Based on the IKDC rating of full giving way64% of those undergoing meniscal transplantation with-out concomitant ACL reconstruction were able to partici-pate in moderate sports activities without instability. Forcomparison, 83% of those undergoing meniscal transplan-tation with concomitant primary ACL reconstruction and75% of those undergoing meniscal transplantation withconcomitant revision ACL reconstruction were able toparticipate in moderate sports activities without instabil-ity.

Similar results were observed when evaluating the in-stability question from the Lysholm Knee Scale. Eighty-two percent of those undergoing meniscal transplantationwithout concomitant ACL reconstruction reported eitherno or rare episodes of instability with strenuous activities.For comparison, none of the individuals undergoing menis-cal transplantation with concomitant primary ACL recon-struction reported episodes of instability, even with stren-uous activity, and 63% of those undergoing meniscal trans-plantation with concomitant revision ACL reconstructionreported either no or rare episodes of instability with stren-uous activities. These differences in instability based uponconcomitant ACL reconstruction were not significantlydifferent. While these results related to instability are en-

178

Table 3 Scores for individual domains of SF-36: raw scores(ranging from 0 to 100 with 100 representing optimal health) andstandardized scores (age- and sex-matched United States popula-tion norms calculated for each individual patient)

Raw Standardized

Physical function 90.0±14.3 –0.18±1.1Role limitation due to 91.4±22.4 0.01±1.0physical problemsBodily pain 85.1±18.5 0.22±0.9General health 84.9±15.2 0.44±0.9 Vitality 72.6±17.8 0.51±0.9Social function 95.7±11.2 0.53±0.6Role limitations due to 94.3±22.0 0.36±0.8emotional problemsMental health 82.9±11.8 0.48±0.7

couraging, we are not able to conclude whether stabilityof the knee is due to the meniscal transplantation, the ACLreconstruction or a combination of the two.

Overall subjective rating

Patients were asked to rate the degree of change in overallfunction and activity level from before surgery to the cur-rent follow-up on a five-point ordinal scale that rangedfrom greatly improved to greatly worse. Overall 22 of the31 stated that they were “greatly improved,” 8 were “some-what improved,” and only 1 reported no change as a resultof the surgery. None of the patients stated that they wereworse. The patients were also rated according their Lys-holm score. Based on the Lysholm Knee Scale 8 patientswere rated as “excellent,” 13 as “good,” 7 as “fair,” and 3as “poor.”

Objective results

Physical examination findings

All 31 patients had a complete physical examination, func-tional testing, and radiographic examination. Twenty-fivehad no effusion while 6 had a small or trace effusion. Noneof the 31 patients had joint line tenderness. Five patientshad some asymmetric joint line swelling, all of whichwere asymptomatic and all were lateral transplants.

Average flexion of the involved knee for all patientswas 128±9° (range 115–150°). The average loss of flexioncompared to the noninvolved knee was 9±7° (range 0–25°).Average extension of the involved knee for all patients was2±4° (range 5° flexion contracture to 7° of hyperextension).The average loss of extension compared to the noninvolvedknee was 3±4° (range 3° greater knee extension to 12° lessknee extension on the involved side).

Anterior stability was assessed with the Lachman’s andpivot shift tests. Preoperatively all 20 patients who wereACL deficient had a 3+ Lachman’s test and a 3+ pivotshift. Postoperatively 19 of 20 had a 1+ Lachman’s and 1+ pivot shift test. The remaining patient had a 2+ Lach-man’s and pivot shift test. No patients had a 3+ Lach-man’s or pivot shift test. KT-1000 results demonstrated a2.0±2.5 mm (range –2.0 to +7.0) increase in translation incomparison to the contralateral knee.

The single leg hop and vertical jump tests were per-formed to assess functional strength. Expressed as a per-centage of the noninvolved leg, the single leg hop andvertical jump averaged 85±19% (range 41–124%) and85±15% (range 54–110%), respectively. Because the sin-gle leg hop and vertical jump tests were not performed be-fore surgery, we are unable to comment on the change infunctional strength as a result of the meniscus transplanta-tion.

Radiographic findings

Joint space width was measured with a digital micrometeron 45° PA flexion weight-bearing radiographs that weretaken before surgery and at the time of the follow-up ex-amination. All measurements were corrected for magnifi-cation. For those that underwent transplantation of themedial meniscus the medial compartment measured 4.9±1.2 mm preoperatively and 5.2±1.5 mm at the time of thefollow-up examination. For those that underwent trans-plantation of the lateral meniscus the lateral compartmentmeasured 4.1±1.8 mm preoperatively and 4.9±1.4 mm atthe time of the follow-up examination. These data implythat there was no progressive narrowing of the compart-ment, and in fact there was a trend for increased width ofthe compartment; however, this increase was not signifi-cant (P=0.50 for the medial compartment and P=0.20 forthe lateral compartment).

Discussion

It is well established that total meniscectomy can lead toosteoarthritis of the knee over time [2, 3, 11, 25, 47]. Ourresults indicate that meniscal allograft transplantation, insymptomatic individuals who have had a previous menis-cectomy with no more than small focal grade III chondro-sis, may provide relief of symptoms and restore relativelyhigh levels of function during ADL. Other researchershave studied the effects of meniscal transplantation. Mila-chowski et al. [32] were the first to report their resultswith meniscal allograft transplantation in 1989. They per-formed medial meniscal transplantation in 22 knees anddemonstrated that meniscal transplantation was a viableoption but raised concerns over the use of freeze driedgrafts (lyophilized) and graft shrinkage. Since then theseauthors have followed their patients a minimum of 12 yearsfollowing the initial procedure [55]. They found that theaverage Lysholm score dropped from 84±12 3 years aftersurgery to 75±23 at the latest follow-up. The fresh-frozengrafts showed relatively good preservation on MRI whilethe lyophilized grafts revealed significant shrinkage, andclinically the patients did similarly to control patients whohad undergone meniscectomy. Van Arkel et al. [49] re-ported the largest series to date of isolated meniscal trans-plantation in the published literature. They performed 23 meniscus transplants using cryopreserved allografts.Analysis of the results 2–5 years after implantation indi-cated that the allografts had healed and functioned well.Three graft failures were thought to be related to malalign-ment. The largest unpublished series to date was by Noyeset al. [33] who performed 96 fresh frozen, irradiatedmeniscal allograft transplants in 82 patients with historyof prior meniscectomy. Using MRI and arthroscopic crite-ria, 9% healed completely, 31% partially healed, and 57%failed.

179

There are many potential technical problems with menis-cus transplantation, including meniscal sizing, anatomicalimplantation, and fixation. Meniscal transplantation at theUniversity of Pittsburgh Medical Center was initiated in1992 after these technical issues were investigated [24].Our initial experience using fresh-frozen, nonirradiated,size-matched meniscal allografts in carefully selected pa-tients has been very encouraging. The vast majority of ourpatients felt that their level of function and activity hadgreatly improved after meniscal transplantation. The KneeOutcome Survey, Lysholm Knee Scale, and SF-36 scoressupport this finding. Following meniscal transplantationwith or without concomitant ACL reconstruction, our pa-tients had reasonably high levels of function during ADL.The patient’s level of function during sports was some-what lower. The level of function was not dependent onwhether the medial or lateral meniscus was transplanted.Additionally, concomitant primary or revision ACL recon-struction and the degree of chondrosis were not significantlyrelated to function at an average follow-up of 2.9 years. Be-cause we did not have a control group and preoperativemeasures of function, it is not possible to state with cer-tainty that the meniscal transplantation was responsiblefor the level of function that we observed in our patientsat follow-up. Despite this limitation our patients appear tobe functioning at a level that is comparable to the age andsex-matched population in the United States, as indicatedby the standardized SF-36 scores.

At latest follow-up most patients did not have pain,swelling, or instability during ADL; however, fewer pa-tients were able to participate in moderate or strenuoussports without symptoms. To explore the effect of menis-cal transplantation with or without concomitant ACL re-construction on instability we examined the IKDC ratingof instability and the instability question from the LysholmKnee Scale. The results indicated that there was no differ-ence in complaints of knee instability at follow-up basedon which meniscus was transplanted or whether the menis-cus transplantation was combined with a primary or revi-sion ACL reconstruction.

Due to the design of this study we are unable to deter-mine whether meniscal transplantation contributed to thelack of instability in these patients. To reduce complaintsof instability and to protect the meniscal allograft we be-lieve that ACL reconstruction, either primary or revision,should be performed concurrently with meniscal transplan-tation in those patients with a symptomatic ACL-deficientknee that has undergone a previous total or subtotal meni-sectomy. We believe that the lack of instability that we ob-served in our patients who had an ACL-deficient kneewas due to the fact that we combined the meniscal trans-plantation with primary or revision ACL reconstruction.Due to the stabilizing effect of the meniscus, we do not be-lieve that we would have had the level of success in termsof instability and pain relief, if we had reconstructed theACL without transplantation of the meniscus in this pop-

ulation of patients. In addition, we believe that a failedACL reconstruction in the setting of an absent medialmeniscus may fail again unless both structures are recon-structed. Both clinical and basic science research supportthese beliefs [1, 27, 29, 44, 45]. Further clinical studiesare needed to definitively determine the benefits of menis-cal transplantation in a symptomatic ACL-deficient kneethat has undergone previous menisectomy.

The findings of the physical examination at follow-upwere encouraging. Most patients were without swellingand joint line tenderness. Range of motion was compara-ble to that of the noninvolved knee. On average our pa-tients had side-to-side difference in knee extension on theorder of 3° and a side-to-side difference in knee flexion onthe order of 9°. Our clinical experience has indicated thatside-to-side differences in extension less than 5° and side-to-side differences in flexion less than 10° are compatiblewith a satisfactory level of function during ADL as wellas during most sports. In addition, manual examination ofligament laxity as well as with the KT-1000 revealed ex-cellent stability. The results of the hop and vertical jumptests imply that these patients had reasonably good strengthand confidence in their knee. Serial radiographs from be-fore meniscal transplantation to the current follow-up didnot reveal any progressive narrowing of the joint space. Infact at latest follow-up our subjects had a slight increasein the joint space compared to that before surgery; how-ever, this increase was not statistically significant.

Initially in our study the senior author had planned toperform second-look arthroscopy on patients undergoingmeniscal transplantation. This was set up as part of theprotocol and discussed with the patients before surgery.However, due to costs, patient inconvenience, the experi-ence of other centers with second-look arthroscopy, andwith basic science studies we elected to discontinue thispart of the clinical follow-up. However, before discontin-uing this portion of the study we did perform second-lookarthroscopy 6–12 months after transplantation in six ofour patients. In all cases the peripheral rim and meniscalinsertions had healed completely. In two of the six cases(both isolated lateral meniscus transplants) radial tearsless than 1 cm in length were noted. At the time of the cur-rent follow-up none of the patients in this study had clini-cal evidence of a retear or failure requiring removal of thegraft.

This study is limited by relatively short follow-up (min-imum 2 years), a heterogeneous patient population, and asmall number of patients. Additionally, the absence of base-line preoperative scores and lack of a control group pre-vent us from stating conclusively that the meniscal trans-plantation resulted in improved function and decreasedsymptoms. However, the results of our first 35 patients un-dergoing meniscal transplantation are encouraging. As ev-idenced by the standardized SF-36 scores, these patientsare functioning at a level that is comparable to age- andsex-matched individuals in the United States population.

180

To date the senior author has performed more than 100 meniscal allograft transplantations. At the time of thisstudy 35 patients were longer than 2 years from surgery.We continue to closely monitor all of our meniscal trans-plantations with the criteria presented in this paper. In thefuture, prospective research with an appropriate controlgroup is needed to provide additional evidence for the ef-fectiveness of meniscal transplantation.

Conclusion

Meniscus transplantation remains a viable treatment optionin carefully selected individuals who present with pain

with or without instability following menisectomy. Ourresults suggest that meniscal transplantation with or with-out ACL reconstruction, in symptomatic individuals whohave had a previous subtotal or total meniscectomy withor without ACL deficiency, may provide relief of symp-toms and restore relatively high levels of function duringADL.

Acknowledgements This investigation was performed at the Cen-ter for Sports Medicine, University of Pittsburgh Medical Center.The views expressed in this article are those of the authors and donot reflect the official policy or position of the Department of theNavy, Department of Defense, or the United States Government.

181

1. Allen CR, Wong EK, Livesay GA,Sakane M, Fu FH, Woo SLY (2000)Importance of the medial meniscus inthe anterior cruciate ligament-deficientknee. J Orthop Trauma 18:109–115

2. Allen PR, Denham RA, Swan AV(1984) Late degenerative changes aftermeniscectomy: factors affecting theknee after the operation. J Bone JointSurg Br 66:666–671

3. Appel H (1970) Late results after menis-cectomy in the knee joint: a clinicaland roentgenologic follow-up investi-gation. Acta Orthop Scand Suppl:133

4. Arnoczky SP, Mcdevitt CA, SchmidtMB (1988) The effect of cryopreserva-tion on canine menisci: a biochemical,morphologic, biomechanical evaluation.J Orthop Res 6:1–12

5. Arnoczky SP, Warren RF, McDevittCA (1990) Meniscal replacement usinga cryopreserved allograft. Clin Orthop252:121–128

6. Cameron JC, Saha S (1997) Meniscalallograft transplantation for unicom-partmental arthritis of the knee. ClinOrthop 337:164–171

7. Cummins JF, Mansour JN, Howe Z,Allan DG (1997) Meniscal transplanta-tion and degenerative articular change:an experimental study in the rabbit.Arthroscopy 13:485–491

8. DeHaven KE, Arnoczky SP (1994)Meniscus repair: basic science, indica-tions for repair, and open repair.AAOS Instr Course Lect 43:65–76

9. DeHaven KE, Lohrer WA, LovelockJE (1995) Long-term results of openmeniscal repair. Am J Sports Med 23:524–530

10. Eggli S, Wegmuller H, Kosina J,Huckell C, Jakob RP (1995) Long-termresults of arthroscopic meniscal repair:an analysis of isolated tears. Am JSports Med 23:715–720

11. Fairbank TJ (1948) Knee joint changesafter meniscectomy. J Bone Joint SurgBr 30:664–670

12. Ferrari JD, Bach BR Jr, Bush-JosephCA, Wang T, Bojchuk J (2001) Ante-rior cruciate ligament reconstruction inmen and women: an outcome analysiscomparing gender. Arthroscopy 17:588–596

13. Fritz J, Irrgang J, Harner CD (1996)Rehabilitation following allograftmeniscal transplantation: a review ofthe literature and case study. J OrthopSports Phys Ther 24:98–106

14. Fukubayashi T, Kurosawa H (1980)The contact area and pressure distribu-tion pattern of the knee. A study ofnormal and osteoarthritic knee joints.Acta Orthop Scand 51:871–879

15. Garrett JC, Stevensen RW (1991)Meniscal transplantation in the humanknee: a preliminary report. Arthroscopy7:57–62

16. Harner CD, Fu FH (1993) The immuneresponse to allograft ACL reconstruc-tion. Am J Knee Surg 6:45–46

17. Harner CD, Olson E, Irrgang, JJ,Silverstein S, Fu FH, Silbey M (1996)Allograft versus autograft anterior cru-ciate ligament reconstruction 3 to 5 yearoutcome. Clin Orthop 324:134–144

18. Hsieh HH, Walker PS (1976) Stabiliz-ing mechanisms of the loaded and un-loaded knee joint. J Bone Joint SurgAm 58:87–93

19. Indelicato PA, Bittar ES, Prevot TJ,Woods GA, Branch TP, Huegel M(1990) Clinical comparison of freeze-dried and fresh frozen patellar tendonallografts for anterior cruciate ligamentreconstruction of the knee. Am JSports Med 18:335–342

20. Irrgang JJ, Snyder-Mackler L, WainerR, Fu FH, Harner CD (1998) Develop-ment of a patient reported measure offunction of the knee. J Bone Joint SurgAm 80:1132–1145

21. Jackson DW, McDevitt CA, SimonTM (1992) Meniscal transplantationusing fresh and cryopreserved allo-grafts: an experimental study in goats.Am J Sports Med 20:644–656

22. Jackson DW, Grood ES, Goldstein JD,Rosen MA, Kurzweil PR, CummingsJF, Simon TM (1993) A comparison ofpatellar tendon autograft and allograftused for ACL reconstruction in thegoat model. Am J Sports Med 21:176–185

23. Johnson DL, Bealle D (1999) Meniscalallograft transplantation. Clin SportsMed 18:93–107

24. Johnson DL, FU FH, Harner CD(1995) Insertion-site anatomy of thehuman menisci: gross, arthroscopic andtopographical anatomy as a basis formeniscal transplantation. Arthroscopy11:386–394

25. Johnson RJ, Kettelkamp DB, Clark W,Leaverton P (1974) Factors affectinglate results after meniscectomy. J BoneJoint Surg Am 56:719–729

26. Jones RE, Smith EC, Reisch JS (1978)Effects of medial menisectomy in pa-tients older then forty years. J BoneJoint Surg Am 60:783–786

27. Levy IM, Torzilli PA, Warren R(1982) The effect of medial meniscec-tomy on anterior-posterior motion ofthe knee. J Bone Joint Surg Am 64:883–888

28. Markolf KL, Mensch JS, Amstutz HC(1976) Stiffness and laxity of the knee– the contributions of the supportingstructures. J Bone Joint Surg Am 58:583–594

References

182

29. McConville OR, Kipnis JM, RichmondJC, Rockett SE, Michaud MJ (1993)The effect of meniscal status on kneestability and function after anterior cru-ciate ligament reconstruction. Arthros-copy 9:431–439

30. McHorney CA, Ware JE Jr, RaczekAE (1993) The MOS 36-item short-form health survey (SF-36). II. Psycho-metric and clinical tests of validity inmeasuring physical and mental healthconstructs. Med Care 31:247–263

31. McHorney CA, Ware JE Jr, Lu JFR,Sherbourne CD (1994) The MOS 36-item short-form health survey (SF-36).III. Tests of data quality, scaling as-sumptions, and reliability across diversepatient groups. Med Care 32:40–66

32. Milachowski KA, Weismeier K, WirthCJ (1989) Homologous meniscal trans-plantation. Int Orthop 13:1–11

33. Noyes FR, Barber-Westin SD (1995)Irradiated meniscal allografts in the hu-man knee: a two- to five-year followup. Orthop Trans 19:417

34. Noyes FR, Barber SD, Mangine RE(1990) Bone-patellar tendon-bone andfascia lata allografts for reconstructionof the ACL. J Bone Joint Surg Am 72:1125–1136

35. Nyland J, Johnson DL, Caborn DN,Brindle T (2002) Internal health statusbelief and lower perceived functionaldeficit are related among anterior cru-ciate ligament-deficient patients. Ar-throscopy 18:515–518

36. Outerbridge RE (1961) The etiology ofchondromalacia patellae. J Bone JointSurg Br 43:752–757

37. Paletta GA, Manning T, Snell E,Parker R, Bergfeld J (1997) The effectof allograft meniscal replacement onintrarticular contact area and pressuresin the human knee. Am J Sports Med25:692–698

38. Pollard ME, Kang Q, Berg EE (1995)Radiographic sizing for meniscal trans-plantation. Arthroscopy 11:684–687

39. Rath E, Richmond JC, Yassir W,Albright JD, Gundogan F (2001) Menis-cal allograft transplantation: two toeight year results. Am J Sports Med29:410–414

40. Rosenberg TD, Paulos LE, Parker RD,Coward DB, Scott SM (1988) Theforty-five degree posterioranterior flex-ion weight-bearing radiograph of theknee. J Bone Joint Surg Am 70:1479–1483

41. Schulte K, Thompson W, Jamison J,Harner CD (1996) The immunologicalresponse to allograft anterior cruciateligament reconstruction: clinical corre-lation. Arthroscopy 12:357–358

42. Seedhom BB, Wright V (1974) Func-tions of the menisci – a preliminarystudy. J Bone Joint Surg Br 56:381–382

43. Shapiro ET, Richmond JC, Rockett SE,McGrath MM, Donaldson WR (1996)The use of a generic, patient basedhealth assessment (SF-36) for evalua-tion of patients with anterior cruciateligament injuries. Am J Sports Med24:196–200

44. Shelbourne KD, Gray T (2000) Resultsof anterior cruciate ligament recon-struction based on meniscus and articu-lar cartilage status at the time of sur-gery: five- to fifteen-year evaluations.Am J Sports Med 28:446–452

45. Shoemaker SC, Markolf KL (1986)The role of the meniscus in the ante-rior-posterior stability of the loaded an-terior cruciate-deficient knee. J BoneJoint Surg Am 68:71–79

46. Stone KR, Rodkey WA, Weber R(1992) Meniscal regeneration withcopolymeric collagen scaffolds. In vitroand in vivo studies evaluated clinically,histologically, and biomechanically.Am J Sports Med 20:73–81

47. Tapper EM, Hoover NW (1969) Lateresults after meniscectomy. J BoneJoint Surg Am 69:517–526

48. Tegner Y, Lysholm J (1985) Ratingsystems in the evaluation of knee liga-ment injuries. Clin Orthop 198:43–49

49. VanArkel ER, DeBoer H (1995) Hu-man meniscal transplantation. J BoneJoint Surg Br 77:589–595

50. Veltri DM, Warren RF (1994) Currentstatus of allograft meniscal transplanta-tion. Clin Orthop 303:44–55

51. Verdonk R (1997) Alternative treat-ments for meniscal injuries. J BoneJoint Surg Br 79:866–873

52. Walker PS, Erkman MJ (1975) Therole of the meniscus in force transmis-sion across the knee. Clin Orthop 109:184–192

53. Ware JE Jr, Sherbourne CD (1992)The MOS 36-item short-form healthsurvey (SF-36). I. Conceptual frame-work and item selection. Med Care 30:473–483

54. Wexler G, Bach BR Jr, Bush-JosephCA, Smink D, Ferrari JD, Bojchuk J(2000) Outcomes of anterior cruciateligament reconstruction in patientswith Worker’s Compensation claims.Arthroscopy 16:49–58

55. Wirth CJ, Peters G, Milachowski KA,Weismeier KG, Kohn D (2002) Long-term results of meniscal allograft trans-plantation. Am J Sports Med 30:174–181

56. Zukor DJ, Brooks PJ, Gross AE (1988)Meniscal allografts-experimental andclinical study. Orthop Rev 17:522