Anterior cruciate ligament (ACL)-deficient knee with degenerative arthrosis: treatment with an isolated autogenous patellar tendon ACL reconstruction

Introduction

The natural history of a knee with a severely damaged orabsent meniscus involves the gradual development ofarthrosis [1, 3, 9]. The anterior cruciate ligament (ACL)protects the menisci by providing stability to the knee.ACL instability frequently results in meniscal tears and

consequent arthrosis [8, 11, 12]. Historically, the treat-ment of meniscal tears in the ACL-deficient knee hasbeen partial or complete meniscectomy. Active patientswith chronic ACL deficiency who have undergone ameniscectomy and who are experiencing symptomatic in-stability may develop degenerative arthrosis rapidly. Be-fore angular deformity arises, however, patients fre-quently present with debilitating knee pain despite having

Abstract We evaluated 58 patients(mean age 30.4 years) who had un-dergone an isolated anterior cruciateligament (ACL) reconstruction forchronic instability (mean time frominjury to surgery, 8.2 ± 5.2 years) andshowed radiographic evidence of de-generative arthrosis. Objective evalu-ation at a mean of 4.1 years postop-eratively included KT-1000 arthrom-eter stability, range of motion, andquadriceps muscle strength testing.Subjective analysis at a mean of 5.5years postoperatively included ratingof pain, stability, activity level, and atotal score both preoperative andpostoperative. Patients were dividedinto two groups: group 1 (n = 28)with a follow-up ≤ 5 years (mean 3.3years); group 2 (n = 30) with a fol-low-up > 5 years (mean 7.2 years).Results were analyzed by length offollow-up and by the grade and com-partment of arthrosis. All patientsenjoyed a full range of motion pre-operatively and postoperatively. Themean KT-1000 arthrometer manualmaximum difference improved from

a mean of 8.2 mm preoperatively to2.4 mm postoperatively. All subjec-tive scores showed statistically sig-nificant improvement over the preop-erative values. Patients with medialcompartment arthrosis reported a bet-ter subjective total score (mean 87)than patients with lateral compart-ment (mean 73) or bicompartmental(mean 79) arthrosis, but there was nota statistically significant difference.There was no correlation betweenpain, stability, or total scores and timeafter surgery. Patients in groups 1 and2 had equal objective stability andsimilar subjective scores, but group 2reported a lower activity level. Anisolated ACL reconstruction can pro-vide long-term stability and sympto-matic pain relief in patients withchronic instability and arthrosis. Theprocedure has low morbidity anddoes not compromise future tibial os-teotomy or total knee replacement.

Key words Anterior cruciate ligament · Arthrosis · Chronic instability

KNEEKnee Surg, Sports Traumatol, Arthrosc(1997) 5 :150–156

© Springer-Verlag 1997

K. Donald ShelbourneKeith C. Stube

Anterior cruciate ligament (ACL)-deficient knee with degenerative arthrosis: treatment with an isolated autogenous patellar tendon ACL reconstruction

Received: 16 September 1996Accepted: 1 March 1997

K. D. Shelbourne (Y) · K. C. StubeMethodist Sports Medicine Center, 1815 North Capitol Avenue, Suite 530, Indianapolis, IN 46202, USATel.: (317) 924-8636 Fax: (317) 921-0230

limited their activities so that instability is not a problem.Currently accepted treatment options for these patients in-clude activity modification, bracing, tibial or femoral os-teotomy, and the combination of osteotomy with ACL re-construction. Patients with gross instability and pain wouldlikely benefit from an ACL reconstruction with or withoutan osteotomy [10]. Patients with pain and limited range ofmotion, no instability, and significant angular deformitywould likely benefit from an osteotomy [2, 7]. There is aselect group of younger patients, however, who seek treat-ment because of pain and occasional instability who donot have good, recognized treatment options. They pre-sent as young (less than 45 years old), active patients withchronic ACL deficiency who have undergone a meniscec-tomy and experience knee pain but do not have frequentepisodes of instability because of activity modification.They show a full range of motion, objective laxity, and ra-diographic evidence of unicompartmental or bicompart-mental arthrosis without angular deformity. The patients’complaints are primarily of pain and secondarily of sub-jective instability, and they are not candidates for an os-teotomy or a knee replacement. An isolated ACL recon-struction, considered by some to be contraindicated in pa-tients with degenerative arthrosis [5], has not been inves-tigated as a long-term treatment option in this group of pa-tients. Shelbourne and Wilckens [17] showed promisingshort-term results in a 4-year follow-up of isolated ACLreconstructions in an active patient population averaging30 years old. The purpose of this study was to evaluate thelong-term results of isolated ACL reconstruction in a younggroup of patients with chronic ACL-deficient knees andarthrosis who presented with primary complaints of painand secondary complaints of instability.

Patients and methods

From 1982 to 1992, 58 arthritic, ACL-deficient patients (mean age30.4 years, range 19–43 years) were surgically treated with an iso-lated ACL reconstruction using an ipsilateral patellar tendon graftby the senior author (K.D.S.). The selection criteria produced agroup of young active patients with chronic ACL deficiency whohad previously undergone a medial and/or lateral meniscectomyand continued to have primary complaints of pain and secondarycomplaints of instability despite conservative care. The mean timefrom injury to surgery was 8.2 ± 5.2 years (range 2.3–23.9 years).All patients had radiographic evidence of degenerative arthrosis, atleast grade 1, in one or more compartments of the knee as seen onposteroanterior, 45 deg, flexed weight-bearing knee [15], lateral,and Merchants radiographs, as read blindly by a radiologist. Thedegree of arthrosis was graded by the radiologist: 0, normal; 1,mild degeneration with 50% decreased joint space (Fig. 1); 2,moderate degeneration with periarticular sclerosis or > 50% jointspace narrowing, no osteophytes; 3, severe degeneration with ex-tensive osteophytes or complete or near complete joint space loss(Fig. 2). Presenting symptoms included knee pain and instabilitywhich required significant activity modification and symptomspersisting despite conservative care. All patients obtained tempo-rary relief of both their pain and instability by a 1-month period ofbracing, using either a custom-fit or off-the-shelf functional bracedesigned for ACL insufficiency. Preoperative and postoperative

objective analysis consisted of testing for stability using a manualmaximum KT-1000 arthrometer score (Med Metric, San Diego,Ca.), isokinetic quadriceps muscle strength at 180 per s (Cybex; aDivision of Lumex, Ronkonkoma, N.Y.), and range of motion.Range of motion measurements were recorded as a/b/c (a = de-grees of hyperextension; b = degrees short of neutral; c = degreesof flexion). Subjective analysis consisted of responses to a modi-fied Noyes questionnaire [16] in which patients evaluated theirpain level, stability, and level of activity on a scale from 0 (worst)to 20 (best) (Fig. 3). The sum of these scores, in addition to the pa-tients’ own evaluation of swelling, walking, running, jumping, andstair climbing, represent a combined total score (scale 0–100 points,100 being the best). All patients underwent an isolated ACL re-construction with a medial patellar miniarthrotomy using a patellartendon autograft and button fixation. Postoperative care followedthe accelerated rehabilitation protocol as previously described[16]. The patients were educated regarding the progression of theirarthrosis and were thus encouraged to limit high impact activitiessuch as long distance running and basketball on a regular basis.

The patients were evaluated at a mean of 5.5 years (range 2.3–12.1 years) following ACL reconstruction. To test the long-termeffect of stabilizing an arthritic, ACL-deficient knee, this groupwas further divided into two: group 1 (n = 28) followed for less

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Fig. 1 Grade 1 arthrosis in the medial and lateral compartment ofthe left knee

Fig. 2 Grade 2 arthrosis in the medial compartment and grade 3arthrosis in the lateral compartment of the right knee

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than 5 years (range 2.0–4.8 years, average 3.3 years); and group 2(n = 30) followed for more than 5 years (range 5.0–12.1 years, av-erage 7.2 years).

Preoperative objective and subjective scores were comparedwith postoperative values, and the results were analyzed based onthe grade and location of arthrosis. The degree of arthrosis on thepreoperative radiograph was correlated with the final result to de-termine if radiographic findings could be predictive of a postoper-ative result.

Statistical analysis was performed by using a Spearman corre-lation coefficient and Student’s t-test, with a P value < 0.05 beingconsidered statistically significant.

Results

All 58 patients returned subjective questionnaires at amean follow-up of 5.5 years after ACL reconstruction(range 2.3–12.1 years; SD ± 2.5). Additional examina-tions for range of motion, KT-1000, and strength scoreswere conducted at their latest clinic visit (mean 4.1 yearsSD ± 2.6; range 2–11 years). Preoperative and postopera-tive subjective responses are summarized in Table 1.

The subjective pain score improved from 8.1 preoper-atively to 15.3 postoperatively (P < 0.05; Table 1). Follow-up at 7.2 years revealed a decline to 14.9. Twenty-one pa-tients (75%) in group 1 (mean follow-up 3.3 years) hadsubjective pain scores greater than or equal to 16 (Table2), and 23 (77%) patients likewise in group 2 (mean fol-

low-up 7.2 years). Two patients reported a worse score forpain after ACL reconstruction.

Objective laxity was present in all patients preopera-tively. The subjective stability score improved from 9.6preoperatively to 19.4 postoperatively (Table 1). Follow-up in the long-term group (group 2) revealed a score of18.7. All group 1 patients had stability scores greater thanor equal to 16 (Table 3), as did 29 patients (97%) in group2. The objective KT-1000 manual maximum differencebetween the ACL reconstructed knee and the non-in-volved knee improved from a mean of 8.2 mm preopera-tively (range 3–14 mm; SD ± 2.9) to 2.4 mm postopera-tively (range –2 to 8 mm; SD ± 1.8). Postoperatively, 45patients (78%) had manual maximum KT-1000 values of3 mm, 11 (19%) had values of 4–5 mm, and 2 (3%) hadvalues > 5 mm.

The activity level score increased from 11.4 preopera-tively to 15.1 postoperatively at 5.5-year follow-up. Ingroup 2, at 7.2-year follow-up, the score decreased to 13.3.Using as a comparison the average preoperative activityscore of 11.4, 27 patients (96%) in group 1 and 27 patients(90%) in group 2 had maintained or increased their activ-ity level at follow-up (Table 4).

The total score gives the patient’s subjective evaluationof their knee. Improvement was noted from 55 preopera-tively to 83 postoperatively (P < 0.05; Table 1). One pa-

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Table 1 Subjective questionnaire results (mean ± SD)

Preoperative Postoperative scoresscores

All patients Group 1a Group 2b

Pain 8.1 ± 3.8 15.3 ± 4.3 15.9 ± 3.7 14.9 ± 5.2Stability 9.6 ± 4.9 19.4 ± 2.3 19.8 ± 0.9 18.7 ± 3.9Activity 11.4 ± 5.0 15.1 ± 3.8 15.9 ± 3.2 13.3 ± 4.3*Total 55.3 ± 15.9 83.0 ± 13.9 86.2 ± 10.3 76.3 ± 18.1

* There was a statistically significant difference between groups 1and 2a Patients followed up 5 years after ACL reconstructionb Patients followed up > 5 years after ACL reconstruction

Table 2 Pain score frequency distribution

Pain score Pre- Postoperativeoperative

All patients Group 1 Group 2(n = 40) (n = 58) (n = 28) (n = 30)

n (%) n (%) n (%) n (%)

0 points 1 (2) 1 (2) 0 (0) 1 (3)4 points 11 (28) 1 (2) 0 (0) 1 (3)8 points 20 (50) 6 (10) 4 (14) 2 (7)


Table 3 Stability score frequency distribution

Stability Pre- Postoperativescore operative


n (%) n (%) n (%) n (%)



Table 4 Activity level score frequency distribution

Activity Pre- Postoperativescore operative


n (%) n (%) n (%) n (%)



tient rated their knee lower than preoperatively at finalfollow-up 6.2 years after ACL reconstruction.

Spearman correlation coefficient analysis of the sub-jective scores revealed a negative correlation between ac-tivity score and time after surgery (CC = –0.33, P < 0.05).No correlation was noted between pain scores, stabilityscores, or total scores and time after surgery.

Objectively, range of motion averaged 4/0/138 preop-eratively and 5/0/138 postoperatively. Isokinetic quadri-ceps muscle strength tests at 180 deg/s revealed a side-to-side difference of 74% preoperatively and 87% postoper-atively. There was no preoperative quadriceps musclestrength recorded for 12 patients.

Thirty-two patients had isolated medial compartmentinvolvement, 5 patients had isolated lateral compartmentinvolvement, and 21 had both compartments involved.Table 5 lists the subjective scores according to the com-partment involved. No statistically significant differencewas noted in the subjective postoperative scores betweenpatients with lateral compartment involvement and pa-tients with medial or bicompartmental arthrosis at fol-low-up. There was a significant difference noted in ac-

tivity scores between medial and bicompartmental in-volvement (P = 0.0363), but not in pain, stability, or to-tal scores.

Tables 6 and 7 separate patients with medial and lateralcompartment involvement by the degree of arthrosis. Nostatistically significant difference in subjective pain, stabil-ity, activity level, and total scores was noted in either group.

Two patients required further operation. One patientunderwent arthroscopic debridement at another institution4 years postoperatively for removal of loose bodies. An-other patient underwent a high tibial osteotomy at 5.5years after ACL reconstruction.

Discussion

ACL-deficient, arthritic, painful knees are a difficultproblem to treat for several reasons. First, to treat theproblem effectively, the etiology of the pain has to be ac-curately identified. Occasionally, the cause is easily iden-tifiable, and an appropriate treatment option can pre-dictably lead to successful results.

Most of the patients who seek treatment at this sportsclinic for chronic ACL deficiency and arthrosis secondaryto previous meniscectomy are young and active. Some ofthem have objective ACL laxity and full range of motionand, therefore, have not become “arthritically stable.” Thepatients have primary complaints of pain with varying de-grees of instability, and their pain likely has a componentof both instability and arthrosis. Subjective improvementin the patients’ symptoms with a trial of bracing suggestedto us that the patients would benefit from ACL stabiliza-tion. It is this select group of young (mean age 30 years),active patients that we elected to review.

Another problem with treating the arthritic, unstableknee is that no good treatment options with long-term fol-low-up have been reported. Patients with isolated medialcompartment arthrosis and ACL deficiency are presentlythought to be good candidates for tibial osteotomy com-bined with ACL reconstruction, either staged or as a com-bined procedure [4, 13, 14]. Although good results havebeen described, this option subjects the patient to the riskof a prolonged surgical procedure, and no long-term fol-low-up (over 5 years has been published yet). Patientswith isolated lateral compartment arthrosis and ACL defi-ciency are thought to benefit from ACL reconstruction withdistal femoral osteotomy, although the results from this pro-cedure are even less predictable. There are also no goodconservative or surgical options for bicompartmental ar-throsis and ACL deficiency. Total knee arthroplasty is notrecommended in this select group of young, active patients.

Traditionally, isolated ACL reconstruction in the ar-thritic knee was believed to be a poor option because it ledto stiffness and increased postoperative pain [5]. We be-lieve that many of the problems previously seen with iso-lated ACL reconstruction in these patients can now be

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Table 5 Compartment involved with arthrosis and postoperativesubjective scores (mean ± SD)

Subjective Medial Lateral Bicompartmentcategory (n = 32) (n = 5) (n = 21)

Pain 16.3 ± 3 10.8 ± 5 14.9 ± 4Stability 19.9 ± 0 20.0 ± 0 18.9 ± 3Activity* 16.0 ± 3 14.4 ± 3 13.7 ± 4Total score 87.0 ± 9 73.0 ± 14 79.4 ± 17

* There was a statistically significant difference between patientswith medial compartment changes alone and patients with bicom-partmental changes

Table 6 Medial compartment arthrosis and postoperative subjec-tive scores (mean ± SD)

Subjective Grade 1 Grade 2 Grade 3category (n = 18) (n = 30) (n = 3)

Pain 16.4 ± 2.7 15.0 ± 4.6 17.3 ± 2.3Stability 20.0 ± 0.0 19.0 ± 4.6 20.0 ± 0.0Activity 16.4 ± 2.7 14.2 ± 4.2 14.7 ± 4.6Total score 89.1 ± 7.5 80.3 ± 15.8 86.0 ± 10.6

Table 7 Lateral compartment arthrosis and postoperative subjec-tive scores (mean ± SD)

Subjective Grade 1 Grade 2 Grade 3category (n = 13) (n = 11) (n = 2)

Pain 14.9 ± 4.8 13.8 ± 5.5 10.0 ± 2.8Stability 19.4 ± 1.5 18.5 ± 4.8 20.0 ± 0.0Activity 15.1 ± 2.9 13.5 ± 4.8 8.0 ± 5.7Total score 82.3 ± 11.6 75.2 ± 21.5 67.5 ± 10.6

avoided secondary to improvements in both operativetechnique and perioperative rehabilitation.

Average subjective pain scores improved from 8.1 pre-operatively to 15.3 postoperatively (P < 0.05). Eighty per-cent of patients had a pain score of 8 or less preopera-tively. Seventy-five percent maintained a pain score of 16at 3.3 years postoperatively, which did not deteriorate by7.2 years (77%).

The activity level was also maintained or increased in81% of patients at 3.3 years and 83% of patients at 7.2years. The preoperative activity level did not appear to af-fect the postoperative scores. Predictably, good results canbe obtained regardless of the patient’s preoperative activ-ity level.

The patient’s subjective satisfaction with the procedureappeared to persist in the long term. Total score, reflectinga combination of the above parameters and overall patientsatisfaction, averaged 55 preoperatively, 86 at 3.3 years,and 80 at 7.2 years. Spearman correlation coefficient analy-sis revealed no correlation between pain, stability, or totalscores and length of time after surgery.

Objective laxity was present in all patients preopera-tively. Subjective stability scores averaged 9.6 preopera-tively and 19.4 postoperatively. Stability scores greaterthan or equal to 16 were maintained from the 3.3-year(100%) to 7.2-year (97%) follow-ups. KT-1000 arthrome-ter results improved from 8.2 mm preoperatively to 2.4mm at 5.5-year follow-up (P < 0.05). Objective stabilitywas maintained from 3.3 years (2.4 mm) to 7.2 years (2.3mm). Two patients had a KT-1000 manual maximum dif-ference > 5 mm at follow-up: one had 7 mm and the other,8 mm. Subjectively, however, a stable knee was obtainedregardless of the degree of preoperative KT-1000 arthro-meter laxity. Both patients with postoperative KT-1000differences > 5 mm had preoperative KT-1000 differencesof 14 mm, which may explain why the patients reportedgood subjective stability after the ACL reconstructiveprocedure.

Patients with isolated medial compartment involvementappeared to do better than those with lateral compartmentor bicompartmental involvement, although statistically sig-nificant differences could not be demonstrated because ofthe low number of patients with isolated lateral compart-ment involvement. There was no statistically significantdifference in results for those with medial compartment in-volvement regardless of their degree of arthrosis. Patientswith grade 3 medial compartment arthrosis, normally idealcandidates for tibial osteotomy, still reported satisfactionwith symptoms at the 7-year follow-up with an isolatedACL reconstruction. If symptoms worsen, as expected withtime, a tibial osteotomy is still a reasonable option with noreason to believe the result of the osteotomy would be in-ferior than if it had been performed earlier. No surgicalbridges are burned with isolated ACL reconstruction.

Young patients with bicompartmental arthrosis havefew good surgical options. Patients with bicompartmental

involvement reported significant improvement in symp-toms when comparing preoperative and postoperative re-sults. A total knee replacement is not a good option be-cause of their age. An isolated ACL reconstruction, on theother hand, offers good long-term results with minimalmorbidity without compromising future surgical options.

Patients with isolated lateral compartment arthrosislikewise have few alternative treatment options. The op-tions include a varus tibial osteotomy for patients withminimal valgus deformity or distal femoral osteotomy [6].Long-term follow-up data on combined valgus osteo-tomy/ACL reconstructions are not available.

Angular deformities were not measured in this study.However, most patients had either isolated medial or lat-eral compartment involvement and, thus, were also candi-dates for osteotomy. The excellent functional result seenwith isolated ACL reconstruction in these patients, de-spite the degree of arthrosis, suggests that this proceduremay effectively delay the need for osteotomy. Most pa-tients comprehend the progressive nature of their diseaseand have restricted their activities voluntarily to limit theprogression of arthrosis. By staging ACL reconstructionand tibial osteotomy several years apart in this population,arthroplasty may be delayed for many years.

The use of button fixation instead of interference screwfixation did not compromise graft fixation at this institu-tion despite the development of aggressive postoperativerehabilitation. Button fixation may be preferable to othertypes of fixation for this population because it does notcompromise future osteotomy. The tibial bone plug isfixed within the proximal tibial bone tunnel so that an os-teotomy can be performed without worrying about tran-secting the patellar tendon graft. Furthermore, no screwremoval is necessary. Button fixation may be a good op-tion in ACL reconstructions in the degenerative knee.

This study can serve as a baseline for comparisonswith surgeons performing other procedures in this patientpopulation: (1) osteotomy alone, (2) combined ACL re-construction with osteotomy, and (3) combined ACL re-construction with meniscal allograft. To our knowledge,in this patient population, there are no studies reportingthese procedures with a follow-up longer than 5 years.

Isolated ACL reconstruction has proven to be a proce-dure that can predictably provide excellent long-term sta-bility with minimal perioperative and postoperative mor-bidity in patients with degenerative knees who have painand instability. This isolated procedure provided pain re-lief, improved stability, increased activity level, and im-proved total knee scores at 7.2 years postoperatively.There was a trend that those with medial compartmentarthrosis had better subjective results than patients withbicompartmental or isolated lateral compartment arthro-sis, but it was not statistically significant. This procedureinvolves minimal morbidity and does not hinder perform-ing later osteotomy if needed.

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References

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Anterior cruciate ligament (ACL)-deficient knee with degenerative arthrosis: treatment with an isolated autogenous patellar tendon ACL reconstruction