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Preoperative anterior knee laxity did not influence postoperative stability restored by anterior cruciate ligament reconstruction
Preoperative Anterior Knee Laxity Did Not Influence Postoperative Stability Restored by Anterior Cruciate Ligament Reconstruction Masayuki Hamada, M.D., Konsei Shino, M.D., Shuji Horibe, M.D., Tomoki Mitsuoka, M.D., Takahide Miyama, M.D., and Yukiyoshi Toritsuka, M.D.
Summary: Eighty-six chronic anterior cruciate ligament (ACL)-injured patients were quantitatively measured for anterior knee stability preoperatively and at 2 years or later (mean, 30 months) postoperatively to examine the influence of preoperative knee laxity on the postoperative knee stability restored by the ACL reconstruction using multiplied hamstring tendon graft. The patients were divided into 3 groups according to the preoperative injured minus normal anterior laxity difference (AL-D) (group I [n ⫽ 27] ⬍5 mm, group II [n ⫽ 48] 5 to 9 mm, group III [n ⫽ 11] ⬎10 mm). The 3 groups were comparable in gender, age, meniscal status, graft excursion measured during operation, time from injury to operation, and activity level. The postoperative AL-D in group I was 0.8 ⫾ 1.7 mm, that in group II was 1.1 ⫾ 1.6 mm, and in group III was 1.5 ⫾ 1.4 mm. There were no significant statistical differences among these 3 groups. With our surgical technique including postoperative rehabilitation, patients with severe instability could be treated successfully without needing any additional procedures such as extra-articular augmentation or specially designed postoperative rehabilitation programs. Key Words: Anterior cruciate ligament reconstruction—Knee stability—Preoperative knee laxity—Hamstring tendon grafts.
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everal factors, such as surgical procedure, graft material, or postoperative rehabilitation program, are known to affect the stability of the restored by anterior cruciate ligament (ACL) reconstruction.1-9 However, it is still unknown how preoperative knee laxity affects postoperative knee stability. It is generally accepted that severe instabilities following ACL disruptions are caused by the functional loss of the ACL in association with stretched secondary stabilizing structures including capsules, menisci, or collateral ligaments.10 If the damage to the secondary restraints affects the remodeling process of the transplanted ACL
graft resulting in increased laxity to the reconstructed knee, the operative procedure and/or the postoperative rehabilitation program should be individualized based on the quantity of the preoperative anterior patholaxity. The purpose of this study was to clarify the overall results of a consecutive series of patients who had been operated on by the 3 surgeons (K.S., M.H., T. Mitsuoka) using the same graft materials, followed by the same postoperative regimen, and to examine the influence of preoperative knee laxity on the postoperative knee stability restored by the ACL reconstruction. MATERIALS AND METHODS
From the Department of Orthopaedic Surgery, Osaka University Medical School (M.H., K.S.); and the Department of Orthopaedic Sports Medicine, Osaka Rosai Hospital (S.H., T. Mitsuoka, T. Miyama, Y.T.), Osaka, Japan. Address correspondence to Konsei Shino, M.D., Department of Orthopaedic Surgery, Osaka University Medical School, 2-2 Yamadaoka, Suita-city, Osaka 565-0871, Japan. r 2000 by the Arthroscopy Association of North America 0749-8063/00/1605-2149$3.00/0 doi:10.1053/jars.2000.5876
Patients Between January 1992 and August 1994, ACL reconstructions were performed with multiple-stranded autogenous hamstring tendons using the arthroscopic 2-incision technique. The indications for the reconstruction were functional instability during daily living or sports activities and complete rupture or absence of the
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ACL as verified by arthroscopy. The inclusion criteria in this study were as follows: (1) no prior intraarticular or extra-articular ligament reconstruction, (2) absence of posterior drawer sign, varus/valgus instability, excessive external tibial rotation compared to the contralateral normal knee, recurvatum, or reversed pivot shift, (3) a healthy contralateral knee, (4) no severe osteoarthritic changes detected by radiography, (5) no restriction of motion of more than 5° in extension or flexion, and (6) no acute cases of injury sustained within 3 weeks (those who visited our hospital during acute phase underwent rehabilitation to regain normal range of motion for correct preoperative laxity measurement). Initially, 132 patients met the inclusion criteria for this study. However, 6 patients were excluded because they had a retear of the reconstructed ACL during strenuous activities. Eight patients were excluded because they had a tear of the contralateral ACL (6 patients) or posterior cruciate ligament (2 patients) while participating in sports before the follow-up examination. Two patients were excluded because they underwent meniscal surgery of the contralateral knee before the follow-up examination. Finally, 29 patients were excluded because they were unavailable for a follow-up examination. Thus, 86 patients underwent an evaluation for a mean follow-up period of 30 months (range, 24 to 55 months). There were 43 male and 43 female patients with a mean age of 24.5 years (range, 14 to 52 years). Average time from injury to surgery was 21 months (range, 1 to 165 months). A total of 57 patients underwent associated meniscal surgery. There were 45 meniscal repairs (23 medial, 22 lateral) and 28 partial or total meniscectomies (13 medial, 15 lateral). According to the activity scale of the Knee Ligament Standard Evaluation Form of the International Knee Documentation Committee (IKDC), 55 patients (64%) were graded as level I, 27 patients (31%) as level II, 3 patients (3%) as level III, and 1 patient (1%) as level IV before injury. ACL Reconstruction The semitendinosus tendon was harvested from the ipsilateral lower limb. The harvest technique was described previously by Maeda et al.11 After harvesting the tendon, it was shaped to more than 7 mm in diameter and at least 60 mm in length by multiplication. If the diameter was less than 7 mm, ipsilateral gracilis tendon was also harvested and doubled to reinforce the semitendinosus graft. Forty-four patients underwent reconstruction with the semitendinosus tendon alone (tripled in 5 patients, quadrupled in 39
patients) and 42 patients had reconstruction with both the semitendinosus (doubled in 3 patients, tripled in 21 patients, quadrupled in 18 patients) and doubled gracilis tendons. The average graft diameter was 8.1 ⫾ 0.6 mm (range, 7 to 9 mm) The operation was performed arthroscopically using 2 arthroscopic portals (anterolateral and anteromedial). Tibial and femoral stumps of the torn ACL were excised to allow anatomic ACL attachment sites to be visualized. A 2.4-mm K-wire was inserted to the center of the tibial ACL attachment site from the anteromedial aspect of the tibia using a commercially available tibial drill guide (Acufex, Mansfield, MA). After the guide wire was reconfirmed to be correctly positioned with a lateral radiograph, it was overdrilled by a 7- to 9-mm diameter cannulated reamer according to the maximum diameter of the graft. The doubled No. 2 suture attached to an isometry testing device (Isotac, Acufex) was screwed to the superior portion of the femoral ACL attachment site. Using the tension isometer, excursion of the trial suture was checked throughout the range of motion. The trial suture should be shortened by 3 to 5 mm approaching full extension to mimic the tension pattern of the normal ACL. After the position of the Isotac was confirmed to be appropriate, a 15- to 25-mm deep femoral socket was created through the tibial drill hole using an endoscopic cannulated reamer. A 2.4-mm K-wire was then placed from the tibial drill hole to the socket and drilled through the proximal anterolateral femoral cortex. The graft was then passed from the tibial tunnel to the femoral tunnel, and graft excursion throughout the entire range of motion was doublechecked using a tension isometer. A notchplasty was performed if the graft impinged on the roof or lateral wall of the notch. Finally, the graft was fixed on both ends under maximum manual tension by tying sutures over buttons or around screws. Postoperative Regimen Postoperatively, the knee was immobilized in a knee brace for 1 week. Partial weight bearing was allowed at 3 weeks, followed by full weight bearing at 5 weeks. Jogging was recommended at 4 months. Full sports activity was allowed 8 to 9 months postoperatively. Evaluation All patients were evaluated qualitatively using the IKDC Knee Ligament Standard Evaluation Form at 24 months or later. For ligament stability evaluation, preoperatively and at follow-up, anterior knee laxity was measured using the Knee Laxity Tester (Orthopedic Systems, Union City, CA). Injured and contralat-
PREOPERATIVE VERSUS POSTOPERATIVE KNEE LAXITY eral normal knees were measured with 30 lb anterior force applied to the proximal tibia at 20° of knee flexion. The side-to-side difference (injured minus normal) in anterior laxity (AL-D) was used as a representative indicator of restored knee stability. For thigh muscle strength analysis, both extension and flexion peak torques were isokinetically measured using the Cybex 6000 dynamometer (Cybex, Division of Lumex, Ronkonkoma, NY) at 60°/second and 180°/second. The value of side-to-side ratio in peak torque for each group was used as the representative parameter for thigh muscle strength. To evaluate the effects of preoperative knee joint laxity on postoperative results, we divided the patients into 3 groups according to the preoperative AL-D (group I [n ⫽ 27] ⬍5 mm, group II [n ⫽ 48] 5 to 9 mm, group III [n ⫽ 11] ⬎10 mm ). As shown in Table 1, the 3 groups were comparable in age, gender, meniscal status, graft excursion measured during operation, time from injury to operation, and activity level (1-way analysis of variance [ANOVA] and -square test). Postoperative AL-D was compared among these groups. Statistical analyses were conducted using StatView IV (Abacus Concepts, Berkeley, CA). To test thigh muscle strength differences between involved and contralateral normal knees, we used a paired t test. To analyze the differences of postoperative AL-D among groups, we used a 1-way ANOVA test. Pearson’s correlation coefficient was used to describe the relationship between preoperative and postoperative AL-D. RESULTS Overall Results Qualitative Evaluation: According to the IKDC subjective assessment, 47 patients (55%) were graded as normal, 35 (41%) as nearly normal, 4 (5%) as
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abnormal, and none (0%) as severely abnormal. Based on the IKDC activity scale, 35 patients (41%) were graded as level I, 31 (36%) as level II, 17 (20%) as level III, and 3 (3%) as level IV. Of the 85 patients who were categorized as level I, II, or III activities, 59 (69%) were able to return to their preinjury activity levels, whereas 26 (31%) reduced their activity level: 4 due to pain; 2 due to instability; and 20 due to social reasons such as graduation from school. Five patients (6%) showed crepitus in the patellofemoral joint: 1 (1%) in the medial femorotibial joint and 6 (7%) in the lateral femorotibial joint. Radiographically, joint space narrowing of the patellofemoral compartment was seen in 4 patients (5%), that of the medial femorotibial compartment in 12 (14%), and that of the lateral femorotibial compartment in 22 (26%), using the flexion weight-bearing view described by Rosenberg et al.12 Knee Joint Stability: Before the operation, all but 7 patients had a grade 2 or 3 pivot shift. At follow-up, 67 (78%) patients had grade 0 and 19 (22%) had a grade 1 pivot shift. The average preoperative AL-D was 5.9 ⫾ 3.1 mm ranging from 1 to 13 mm. The postoperative AL-D was reduced to 1.0 ⫾ 1.7 mm with a range from ⫺3 to 5 mm. Eighty-one of 86 patients (94%) showed ⫾3 mm or less of AL-D and 5 patients (6%) showed more than 3 mm of AL-D (3 patients, 4 mm; 2 patients, 5 mm) (Fig 1). Thigh Muscle Strength: Overall data are listed in Table 2. The mean isokinetic peak extension torques for the involved limb were 91% and 95% of the contralateral healthy limb at 60°/second and 180°/ second, respectively. The differences between the involved limbs and the uninvolved were significant (P ⬍ .0001, paired t test). The mean isokinetic peak flexion torques for the involved limb were 96% and 97% of the contralateral healthy limb at 60°/second
TABLE 1. Demographics of the Groups Group Preop AL-D
Group I ⬍4 mm
Group II 5-9 mm
Group III ⬎10 mm
No. of pts Age (yr) Gender (M/F) Meniscal status (preserved/excised) Graft excursion (mm) IKDC activity level preop (I/II, III, IV) IKDC activity level postop (I/II, III, IV) Time to surgery (mo)
27 24.3 ⫾ 10.0 11/16 19/8 1.8 ⫾ 0.9 15/12 10/17 13.8 ⫾ 32.4
48 25.2 ⫾ 7.5 26/22 34/14 1.9 ⫾ 1.0 32/16 19/29 26.3 ⫾ 36.5
11 21.8 ⫾ 4.4 6/5 8/3 1.9 ⫾ 1.1 8/3 6/5 19.4 ⫾ 29.9
NOTE. Menisci status: excised is partial or subtotal excision. Abbreviation: AL-D, side-to-side difference in anterior laxity.
P Value Statistics
.44 .51 .99 .95 .51 .59 .32
1-way ANOVA -square -square 1-way ANOVA -square -square 1-way ANOVA
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M. HAMADA ET AL. group III (⬎10 mm of preoperative AL-D) was 1.5 ⫾ 1.4 mm (range, ⫺1 to 3 mm). There were no statistical differences among these 3 groups (1-way ANOVA, P ⫽ .40) (Fig 2). In addition, there was no positive correlation between the preoperative and the postoperative AL-D. The correlation coefficient was 0.15 (Fig 3). DISCUSSION
FIGURE 1. (A) The distribution of preoperative side-to-side difference in anterior laxity (AL-D). (B) The distribution of postoperative side-to-side difference in anterior laxity (AL-D).
and 180°/second, respectively. The side-to-side differences were also significant (P ⬍ .01, paired t test).
Several reports have discussed the effectiveness of the extra-articular procedures combined with intraarticular ACL reconstruction. In 1982, Clancy et al.13 stated that combined extra-articular procedures were performed in all cases to correct for capsular laxity and to decrease the load on the ACL graft. Noyes and Barber6 reported in 1991 that extra-articular procedures combined with intra-articular ACL reconstruction provided better postoperative knee stability than intra-articular ACL reconstruction alone. On the other hand, Shino et al.14 in 1990, Roth et al.15 in 1987, and Noyes and Barber16 in 1996 showed that the combined extra-articular procedures did not improve the efficacy of an intra-articular reconstruction. Because combined extra-articular procedures are complex and nonanatomic, surgeons currently tend to reconstruct the ACL using intra-articular procedures alone. However, no consensus exists on the treatment of patients with chronic severe anterior laxity, and this study is the first to investigate this issue. In our research of chronic ACL-injured patients, we found that preoperative AL-D did not affect the postoperative results. That is to say, patients with chronic severe anterior instability were successfully treated with regular reconstructive surgery. This finding could be explained as follows: the techniques of intra-articular reconstruction and
Preoperative Versus Postoperative Laxity Testing The postoperative AL-D in group I (0 to 4 mm of preoperative AL-D) was 0.8 ⫾ 1.7 mm (range, ⫺1 to 5 mm), that in group II (5 to 9 mm of preoperative AL-D) was 1.1 ⫾ 1.6 mm (range, ⫺2 to 4 mm), and in TABLE 2. Cybex Isokinetic Muscle Strength Analysis of the Knees (mean ⫾ SD)
Extension 60°/sec 180°/sec Flexion 60°/sec 180°/sec
Involved (N-m)
Contralateral (N-m)
Involved/ Contralateral (%)
143.1 ⫾ 43.4 93.0 ⫾ 30.4
158.4 ⫾ 42.6 99.4 ⫾ 30.2
90.8 ⫾ 15.6 94.9 ⫾ 16.3
79.7 ⫾ 26.3 58.3 ⫾ 21.2
83.6 ⫾ 26.2 60.6 ⫾ 20.5
96.1 ⫾ 13.7 97.3 ⫾ 16.6
FIGURE 2. Postoperative side-to-side difference in anterior laxity (AL-D) in each group.
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stability, although statistics do not show a significant difference between the 2 studies (P ⫽ .23, MannWhitney U test). This could be explained for 2 reasons. One is the development of the endoscopic ACL drill guide system. This system has made it possible for us to directly drill a femoral hole. Consequently, the femoral hole was drilled more accurately than the previous rear-entry ACL drill guide system. The other reason could be the difference in force applied to the proximal tibia when the quantitative laxity tests were performed. The applied force of 30 lb in this study was less than the 200 N used in the previous study. FIGURE 3. The relationship between the preoperative and postoperative AL-D (␥ ⫽ 0.15).
postoperative rehabilitation programs have been progressively improved owing to the many experimental and clinical studies on the ACL and transplanted ACL grafts. These factors may have diminished the adverse effects of the slackened secondary restraints on healing of the ACL graft and led to the improvement in postoperative knee stability achieved by intra-articular reconstruction. We have to point out that this study was conducted under less aggressive postoperative rehabilitation programs. It is natural to think that a more aggressive rehabilitation program may alter the results. With this study, however, we could not draw any conclusion on this issue. Aggressive rehabilitation was advocated to prevent postoperative extension loss, arthrofibrosis, or quadriceps weakness resulting from ACL reconstruction, particularly in patients using autogenous bone– patellar tendon–bone grafts.17,18 We have previously reported that these kind of complications are not common after reconstruction in patients using semitendinosus tendon, even though they were rehabilitated with a less aggressive rehabilitation protocol.11 Therefore, at present we do not feel the necessity of aggressive rehabilitation after using semitendinosus tendon as a graft. Finally, we would like to compare the results of this study with those of our previous study to evaluate whether the endoscopic technique (femoral socket created through the tibial tunnel) shows any advantages over the 2-incision technique with rear-entry guide.11 Graft materials (autogenous multistranded semitendinosus and/or gracilis tendons) and postoperative rehabilitation programs are the same in both studies. The mean AL-D in this study was 1.0 mm and in the previous study was 1.5 mm. The current study may provide better results in restoring anterior knee
CONCLUSIONS ACL reconstruction using multistranded autogenous hamstring tendons provided satisfactory stability. Preoperative knee laxity did not influence postoperative stability.
REFERENCES 1. Aglietti P, Zaccherotti G, Menchetti PP, De BP. A comparison of clinical and radiological parameters with two arthroscopic techniques for anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 1995;3:2-8. 2. Harter RA, Osternig LR, Standifer LW. Isokinetic evaluation of quadriceps and hamstrings symmetry following anterior cruciate ligament reconstruction. Arch Phys Med Rehabil 1990;71: 465-468. 3. Holm I, Hammer S, Larsen S, Nordsletten L, Steen H. Can a regular leg extension bench be used in testing deficits of the quadriceps muscle during rehabilitation? Scand J Med Sci Sports 1995;5:29-35. 4. Indelicato PA, Bittar ES, Prevot TJ, Woods GA, Branch TP, Huegel M. Clinical comparison of freeze-dried and fresh frozen patellar tendon allografts for anterior cruciate ligament reconstruction of the knee. Am J Sports Med 1990;18:335-342. 5. Marder RA, Raskind JR, Carroll M. Prospective evaluation of arthroscopically assisted anterior cruciate ligament reconstruction. Patellar tendon versus semitendinosus and gracilis tendons. Am J Sports Med 1991;19:478-484. 6. Noyes FR, Barber SD. The effect of an extra-articular procedure on allograft reconstructions for chronic ruptures of the anterior cruciate ligament. J Bone Joint Surg Am 1991;73:882892. 7. Otero AL, Hutcheson L. A comparison of the doubled semitendinosus/gracilis and central third of the patellar tendon autografts in arthroscopic anterior cruciate ligament reconstruction. Arthroscopy 1993;9:143-148. 8. Shino K, Nakata K, Horibe S, Inoue M, Nakagawa S. Quantitative evaluation after arthroscopic anterior cruciate ligament reconstruction. Allograft versus autograft. Am J Sports Med 1993;21:609-616. 9. Specchiulli F, Laforgia R, Mocci A, Miolla L, Scialpi L, Solarino GJ. Anterior cruciate ligament reconstruction. A comparison of 2 techniques. Clin Orthop 1995;311:142-147. 10. Butler DL, Noyes FR, Grood ES. Ligamentous restraints to anterior-posterior drawer in the human knee. A biomechanical study. J Bone Joint Surg Am 1980;62:259-270.
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11. Maeda A, Shino K, Horibe S, Nakata K, Buccafusca G. Anterior cruciate ligament reconstruction with multistranded autogenous semitendinosus tendon. Am J Sports Med 1996;24: 504-509. 12. Rosenberg TD, Paulos LE, Parker RD, Coward DB, Scott SM. The forty-five-degree posteroanterior flexion weight-bearing radiograph of the knee. J Bone Joint Surg Am 1988;70:14791483. 13. Clancy WJ, Nelson DA, Reider B, Narechania RG. Anterior cruciate ligament reconstruction using one-third of the patellar ligament, augmented by extra-articular tendon transfers. J Bone Joint Surg Am 1982;64:352-359. 14. Shino K, Inoue M, Horibe S, Hamada M, Ono K. Reconstruction of the anterior cruciate ligament using allogeneic tendon. Long-term follow-up. Am J Sports Med 1990;18:457-465.
15. Roth JH, Kennedy JC, Lockstadt H, McCallum CL, Cunning LA. Intra-articular reconstruction of the anterior cruciate ligament with and without extra-articular supplementation by transfer of the biceps femoris tendon. J Bone Joint Surg Am 1987;69:275-278. 16. Noyes FR, Barber WS. Reconstruction of the anterior cruciate ligament with human allograft. Comparison of early and later results. J Bone Joint Surg Am 1996;78:524-537. 17. Shelbourne KD, Klootwyk TE, Wilckens JH, De Carlo MS. Ligament stability two to six years after anterior cruciate ligament reconstruction with autogenous patellar tendon graft and participation in accelerated rehabilitation program. Am J Sports Med 1995;23:575-579. 18. Shelbourne KD, Nitz P. Accelerated rehabilitation after anterior cruciate ligament reconstruction. Am J Sports Med 1990;18:292299.
Summary: Eighty-six chronic anterior cruciate ligament (ACL)-injured patients were quantitatively measured for anterior knee stability preoperatively and at 2 years or later (mean, 30 months) postoperatively to examine the influence of preoperative knee laxity on the postoperative knee stability restored by the ACL reconstruction using multiplied hamstring tendon graft. The patients were divided into 3 groups according to the preoperative injured minus normal anterior laxity difference (AL-D) (group I [n ⫽ 27] ⬍5 mm, group II [n ⫽ 48] 5 to 9 mm, group III [n ⫽ 11] ⬎10 mm). The 3 groups were comparable in gender, age, meniscal status, graft excursion measured during operation, time from injury to operation, and activity level. The postoperative AL-D in group I was 0.8 ⫾ 1.7 mm, that in group II was 1.1 ⫾ 1.6 mm, and in group III was 1.5 ⫾ 1.4 mm. There were no significant statistical differences among these 3 groups. With our surgical technique including postoperative rehabilitation, patients with severe instability could be treated successfully without needing any additional procedures such as extra-articular augmentation or specially designed postoperative rehabilitation programs. Key Words: Anterior cruciate ligament reconstruction—Knee stability—Preoperative knee laxity—Hamstring tendon grafts.
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everal factors, such as surgical procedure, graft material, or postoperative rehabilitation program, are known to affect the stability of the restored by anterior cruciate ligament (ACL) reconstruction.1-9 However, it is still unknown how preoperative knee laxity affects postoperative knee stability. It is generally accepted that severe instabilities following ACL disruptions are caused by the functional loss of the ACL in association with stretched secondary stabilizing structures including capsules, menisci, or collateral ligaments.10 If the damage to the secondary restraints affects the remodeling process of the transplanted ACL
graft resulting in increased laxity to the reconstructed knee, the operative procedure and/or the postoperative rehabilitation program should be individualized based on the quantity of the preoperative anterior patholaxity. The purpose of this study was to clarify the overall results of a consecutive series of patients who had been operated on by the 3 surgeons (K.S., M.H., T. Mitsuoka) using the same graft materials, followed by the same postoperative regimen, and to examine the influence of preoperative knee laxity on the postoperative knee stability restored by the ACL reconstruction. MATERIALS AND METHODS
From the Department of Orthopaedic Surgery, Osaka University Medical School (M.H., K.S.); and the Department of Orthopaedic Sports Medicine, Osaka Rosai Hospital (S.H., T. Mitsuoka, T. Miyama, Y.T.), Osaka, Japan. Address correspondence to Konsei Shino, M.D., Department of Orthopaedic Surgery, Osaka University Medical School, 2-2 Yamadaoka, Suita-city, Osaka 565-0871, Japan. r 2000 by the Arthroscopy Association of North America 0749-8063/00/1605-2149$3.00/0 doi:10.1053/jars.2000.5876
Patients Between January 1992 and August 1994, ACL reconstructions were performed with multiple-stranded autogenous hamstring tendons using the arthroscopic 2-incision technique. The indications for the reconstruction were functional instability during daily living or sports activities and complete rupture or absence of the
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 16, No 5 (July-August), 2000: pp 477–482
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ACL as verified by arthroscopy. The inclusion criteria in this study were as follows: (1) no prior intraarticular or extra-articular ligament reconstruction, (2) absence of posterior drawer sign, varus/valgus instability, excessive external tibial rotation compared to the contralateral normal knee, recurvatum, or reversed pivot shift, (3) a healthy contralateral knee, (4) no severe osteoarthritic changes detected by radiography, (5) no restriction of motion of more than 5° in extension or flexion, and (6) no acute cases of injury sustained within 3 weeks (those who visited our hospital during acute phase underwent rehabilitation to regain normal range of motion for correct preoperative laxity measurement). Initially, 132 patients met the inclusion criteria for this study. However, 6 patients were excluded because they had a retear of the reconstructed ACL during strenuous activities. Eight patients were excluded because they had a tear of the contralateral ACL (6 patients) or posterior cruciate ligament (2 patients) while participating in sports before the follow-up examination. Two patients were excluded because they underwent meniscal surgery of the contralateral knee before the follow-up examination. Finally, 29 patients were excluded because they were unavailable for a follow-up examination. Thus, 86 patients underwent an evaluation for a mean follow-up period of 30 months (range, 24 to 55 months). There were 43 male and 43 female patients with a mean age of 24.5 years (range, 14 to 52 years). Average time from injury to surgery was 21 months (range, 1 to 165 months). A total of 57 patients underwent associated meniscal surgery. There were 45 meniscal repairs (23 medial, 22 lateral) and 28 partial or total meniscectomies (13 medial, 15 lateral). According to the activity scale of the Knee Ligament Standard Evaluation Form of the International Knee Documentation Committee (IKDC), 55 patients (64%) were graded as level I, 27 patients (31%) as level II, 3 patients (3%) as level III, and 1 patient (1%) as level IV before injury. ACL Reconstruction The semitendinosus tendon was harvested from the ipsilateral lower limb. The harvest technique was described previously by Maeda et al.11 After harvesting the tendon, it was shaped to more than 7 mm in diameter and at least 60 mm in length by multiplication. If the diameter was less than 7 mm, ipsilateral gracilis tendon was also harvested and doubled to reinforce the semitendinosus graft. Forty-four patients underwent reconstruction with the semitendinosus tendon alone (tripled in 5 patients, quadrupled in 39
patients) and 42 patients had reconstruction with both the semitendinosus (doubled in 3 patients, tripled in 21 patients, quadrupled in 18 patients) and doubled gracilis tendons. The average graft diameter was 8.1 ⫾ 0.6 mm (range, 7 to 9 mm) The operation was performed arthroscopically using 2 arthroscopic portals (anterolateral and anteromedial). Tibial and femoral stumps of the torn ACL were excised to allow anatomic ACL attachment sites to be visualized. A 2.4-mm K-wire was inserted to the center of the tibial ACL attachment site from the anteromedial aspect of the tibia using a commercially available tibial drill guide (Acufex, Mansfield, MA). After the guide wire was reconfirmed to be correctly positioned with a lateral radiograph, it was overdrilled by a 7- to 9-mm diameter cannulated reamer according to the maximum diameter of the graft. The doubled No. 2 suture attached to an isometry testing device (Isotac, Acufex) was screwed to the superior portion of the femoral ACL attachment site. Using the tension isometer, excursion of the trial suture was checked throughout the range of motion. The trial suture should be shortened by 3 to 5 mm approaching full extension to mimic the tension pattern of the normal ACL. After the position of the Isotac was confirmed to be appropriate, a 15- to 25-mm deep femoral socket was created through the tibial drill hole using an endoscopic cannulated reamer. A 2.4-mm K-wire was then placed from the tibial drill hole to the socket and drilled through the proximal anterolateral femoral cortex. The graft was then passed from the tibial tunnel to the femoral tunnel, and graft excursion throughout the entire range of motion was doublechecked using a tension isometer. A notchplasty was performed if the graft impinged on the roof or lateral wall of the notch. Finally, the graft was fixed on both ends under maximum manual tension by tying sutures over buttons or around screws. Postoperative Regimen Postoperatively, the knee was immobilized in a knee brace for 1 week. Partial weight bearing was allowed at 3 weeks, followed by full weight bearing at 5 weeks. Jogging was recommended at 4 months. Full sports activity was allowed 8 to 9 months postoperatively. Evaluation All patients were evaluated qualitatively using the IKDC Knee Ligament Standard Evaluation Form at 24 months or later. For ligament stability evaluation, preoperatively and at follow-up, anterior knee laxity was measured using the Knee Laxity Tester (Orthopedic Systems, Union City, CA). Injured and contralat-
PREOPERATIVE VERSUS POSTOPERATIVE KNEE LAXITY eral normal knees were measured with 30 lb anterior force applied to the proximal tibia at 20° of knee flexion. The side-to-side difference (injured minus normal) in anterior laxity (AL-D) was used as a representative indicator of restored knee stability. For thigh muscle strength analysis, both extension and flexion peak torques were isokinetically measured using the Cybex 6000 dynamometer (Cybex, Division of Lumex, Ronkonkoma, NY) at 60°/second and 180°/second. The value of side-to-side ratio in peak torque for each group was used as the representative parameter for thigh muscle strength. To evaluate the effects of preoperative knee joint laxity on postoperative results, we divided the patients into 3 groups according to the preoperative AL-D (group I [n ⫽ 27] ⬍5 mm, group II [n ⫽ 48] 5 to 9 mm, group III [n ⫽ 11] ⬎10 mm ). As shown in Table 1, the 3 groups were comparable in age, gender, meniscal status, graft excursion measured during operation, time from injury to operation, and activity level (1-way analysis of variance [ANOVA] and -square test). Postoperative AL-D was compared among these groups. Statistical analyses were conducted using StatView IV (Abacus Concepts, Berkeley, CA). To test thigh muscle strength differences between involved and contralateral normal knees, we used a paired t test. To analyze the differences of postoperative AL-D among groups, we used a 1-way ANOVA test. Pearson’s correlation coefficient was used to describe the relationship between preoperative and postoperative AL-D. RESULTS Overall Results Qualitative Evaluation: According to the IKDC subjective assessment, 47 patients (55%) were graded as normal, 35 (41%) as nearly normal, 4 (5%) as
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abnormal, and none (0%) as severely abnormal. Based on the IKDC activity scale, 35 patients (41%) were graded as level I, 31 (36%) as level II, 17 (20%) as level III, and 3 (3%) as level IV. Of the 85 patients who were categorized as level I, II, or III activities, 59 (69%) were able to return to their preinjury activity levels, whereas 26 (31%) reduced their activity level: 4 due to pain; 2 due to instability; and 20 due to social reasons such as graduation from school. Five patients (6%) showed crepitus in the patellofemoral joint: 1 (1%) in the medial femorotibial joint and 6 (7%) in the lateral femorotibial joint. Radiographically, joint space narrowing of the patellofemoral compartment was seen in 4 patients (5%), that of the medial femorotibial compartment in 12 (14%), and that of the lateral femorotibial compartment in 22 (26%), using the flexion weight-bearing view described by Rosenberg et al.12 Knee Joint Stability: Before the operation, all but 7 patients had a grade 2 or 3 pivot shift. At follow-up, 67 (78%) patients had grade 0 and 19 (22%) had a grade 1 pivot shift. The average preoperative AL-D was 5.9 ⫾ 3.1 mm ranging from 1 to 13 mm. The postoperative AL-D was reduced to 1.0 ⫾ 1.7 mm with a range from ⫺3 to 5 mm. Eighty-one of 86 patients (94%) showed ⫾3 mm or less of AL-D and 5 patients (6%) showed more than 3 mm of AL-D (3 patients, 4 mm; 2 patients, 5 mm) (Fig 1). Thigh Muscle Strength: Overall data are listed in Table 2. The mean isokinetic peak extension torques for the involved limb were 91% and 95% of the contralateral healthy limb at 60°/second and 180°/ second, respectively. The differences between the involved limbs and the uninvolved were significant (P ⬍ .0001, paired t test). The mean isokinetic peak flexion torques for the involved limb were 96% and 97% of the contralateral healthy limb at 60°/second
TABLE 1. Demographics of the Groups Group Preop AL-D
Group I ⬍4 mm
Group II 5-9 mm
Group III ⬎10 mm
No. of pts Age (yr) Gender (M/F) Meniscal status (preserved/excised) Graft excursion (mm) IKDC activity level preop (I/II, III, IV) IKDC activity level postop (I/II, III, IV) Time to surgery (mo)
27 24.3 ⫾ 10.0 11/16 19/8 1.8 ⫾ 0.9 15/12 10/17 13.8 ⫾ 32.4
48 25.2 ⫾ 7.5 26/22 34/14 1.9 ⫾ 1.0 32/16 19/29 26.3 ⫾ 36.5
11 21.8 ⫾ 4.4 6/5 8/3 1.9 ⫾ 1.1 8/3 6/5 19.4 ⫾ 29.9
NOTE. Menisci status: excised is partial or subtotal excision. Abbreviation: AL-D, side-to-side difference in anterior laxity.
P Value Statistics
.44 .51 .99 .95 .51 .59 .32
1-way ANOVA -square -square 1-way ANOVA -square -square 1-way ANOVA
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M. HAMADA ET AL. group III (⬎10 mm of preoperative AL-D) was 1.5 ⫾ 1.4 mm (range, ⫺1 to 3 mm). There were no statistical differences among these 3 groups (1-way ANOVA, P ⫽ .40) (Fig 2). In addition, there was no positive correlation between the preoperative and the postoperative AL-D. The correlation coefficient was 0.15 (Fig 3). DISCUSSION
FIGURE 1. (A) The distribution of preoperative side-to-side difference in anterior laxity (AL-D). (B) The distribution of postoperative side-to-side difference in anterior laxity (AL-D).
and 180°/second, respectively. The side-to-side differences were also significant (P ⬍ .01, paired t test).
Several reports have discussed the effectiveness of the extra-articular procedures combined with intraarticular ACL reconstruction. In 1982, Clancy et al.13 stated that combined extra-articular procedures were performed in all cases to correct for capsular laxity and to decrease the load on the ACL graft. Noyes and Barber6 reported in 1991 that extra-articular procedures combined with intra-articular ACL reconstruction provided better postoperative knee stability than intra-articular ACL reconstruction alone. On the other hand, Shino et al.14 in 1990, Roth et al.15 in 1987, and Noyes and Barber16 in 1996 showed that the combined extra-articular procedures did not improve the efficacy of an intra-articular reconstruction. Because combined extra-articular procedures are complex and nonanatomic, surgeons currently tend to reconstruct the ACL using intra-articular procedures alone. However, no consensus exists on the treatment of patients with chronic severe anterior laxity, and this study is the first to investigate this issue. In our research of chronic ACL-injured patients, we found that preoperative AL-D did not affect the postoperative results. That is to say, patients with chronic severe anterior instability were successfully treated with regular reconstructive surgery. This finding could be explained as follows: the techniques of intra-articular reconstruction and
Preoperative Versus Postoperative Laxity Testing The postoperative AL-D in group I (0 to 4 mm of preoperative AL-D) was 0.8 ⫾ 1.7 mm (range, ⫺1 to 5 mm), that in group II (5 to 9 mm of preoperative AL-D) was 1.1 ⫾ 1.6 mm (range, ⫺2 to 4 mm), and in TABLE 2. Cybex Isokinetic Muscle Strength Analysis of the Knees (mean ⫾ SD)
Extension 60°/sec 180°/sec Flexion 60°/sec 180°/sec
Involved (N-m)
Contralateral (N-m)
Involved/ Contralateral (%)
143.1 ⫾ 43.4 93.0 ⫾ 30.4
158.4 ⫾ 42.6 99.4 ⫾ 30.2
90.8 ⫾ 15.6 94.9 ⫾ 16.3
79.7 ⫾ 26.3 58.3 ⫾ 21.2
83.6 ⫾ 26.2 60.6 ⫾ 20.5
96.1 ⫾ 13.7 97.3 ⫾ 16.6
FIGURE 2. Postoperative side-to-side difference in anterior laxity (AL-D) in each group.
PREOPERATIVE VERSUS POSTOPERATIVE KNEE LAXITY
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stability, although statistics do not show a significant difference between the 2 studies (P ⫽ .23, MannWhitney U test). This could be explained for 2 reasons. One is the development of the endoscopic ACL drill guide system. This system has made it possible for us to directly drill a femoral hole. Consequently, the femoral hole was drilled more accurately than the previous rear-entry ACL drill guide system. The other reason could be the difference in force applied to the proximal tibia when the quantitative laxity tests were performed. The applied force of 30 lb in this study was less than the 200 N used in the previous study. FIGURE 3. The relationship between the preoperative and postoperative AL-D (␥ ⫽ 0.15).
postoperative rehabilitation programs have been progressively improved owing to the many experimental and clinical studies on the ACL and transplanted ACL grafts. These factors may have diminished the adverse effects of the slackened secondary restraints on healing of the ACL graft and led to the improvement in postoperative knee stability achieved by intra-articular reconstruction. We have to point out that this study was conducted under less aggressive postoperative rehabilitation programs. It is natural to think that a more aggressive rehabilitation program may alter the results. With this study, however, we could not draw any conclusion on this issue. Aggressive rehabilitation was advocated to prevent postoperative extension loss, arthrofibrosis, or quadriceps weakness resulting from ACL reconstruction, particularly in patients using autogenous bone– patellar tendon–bone grafts.17,18 We have previously reported that these kind of complications are not common after reconstruction in patients using semitendinosus tendon, even though they were rehabilitated with a less aggressive rehabilitation protocol.11 Therefore, at present we do not feel the necessity of aggressive rehabilitation after using semitendinosus tendon as a graft. Finally, we would like to compare the results of this study with those of our previous study to evaluate whether the endoscopic technique (femoral socket created through the tibial tunnel) shows any advantages over the 2-incision technique with rear-entry guide.11 Graft materials (autogenous multistranded semitendinosus and/or gracilis tendons) and postoperative rehabilitation programs are the same in both studies. The mean AL-D in this study was 1.0 mm and in the previous study was 1.5 mm. The current study may provide better results in restoring anterior knee
CONCLUSIONS ACL reconstruction using multistranded autogenous hamstring tendons provided satisfactory stability. Preoperative knee laxity did not influence postoperative stability.
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