Evaluation of active knee flexion and hamstring strength after anterior cruciate ligament reconstruction using hamstring tendons

Purpose: The purpose of this study was to evaluate active knee flexion range of motion and hamstring strength following hamstring anterior cruciate ligament (ACL) reconstruction. Type of Study: Case control study, consecutive sample. Methods: Seventy-four consecutive patients who had undergone hamstring ACL reconstruction underwent isokinetic muscle strength testing at 2 years post surgery. Measurements of the maximum standing active knee flexion angle with the hip extended were also taken. During isokinetic testing, we evaluated flexion torque at 90° of knee flexion, in addition to the peak flexion torque. We further compared these parameters of muscle strength around the knee for the patients in whom only semitendinosus tendon was harvested as a graft source (ST group), and those from whom the semitendinosus tendon and the gracilis tendon were harvested (ST/G group). Results: Isokinetic testing showed that, in both the ST and ST/G groups, the knee flexor strength of the involved leg was less effectively restored at 90° of knee flexion than at the angle at which the peak torque was generated. Conversely, no significant difference was seen in the side-to-side ratio in either the peak flexion torque or the 90° flexion torque between the groups. The side-to-side ratio in mean maximum standing knee flexion angle was significantly lower in the ST/G group than in the ST group. Conclusions: This study suggests that the loss of knee flexor strength following the harvest of the hamstring tendons may be more significant than has been previously estimated. Furthermore, multiple tendon harvest may affect the range of active knee flexion.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 6 (July-August), 2002: pp 598–602     

Rotational muscle strength of the limb after anterior cruciate ligament reconstruction using semitendinosus and gracilis tendon

Purpose: To investigate the influence of harvesting semitendinosus and gracilis tendons on the rotational muscle strength of the limb after anterior cruciate ligament (ACL) reconstruction. Type of Study: Prospective study. Methods: We performed a prospective study of 62 consecutive (34 male, 28 female) patients with ACL reconstructions using the semitendinosus and gracilis tendons. The mean age at surgery was 20.8 years. The semitendinosus tendon was harvested in 32 patients (ST group), and semitendinosus and gracilis tendons in 30 patients (STG group). The peak isokinetic torques for extension, flexion, internal rotation, and external rotation were measured before and 12 months after ACL reconstruction using the Cybex 6000B system (Cybex Division of Lumex, Ronkonkoma, NY). The rotational torque was measured at 30°/sec and 120°/sec. Results: Before reconstruction, the mean isokinetic peak torque of the involved limb was decreased in extension and internal rotation. The mean isokinetic peak torque of the involved limb in extension recovered 12 months after ACL reconstruction; however, the weakness in internal rotation persisted. The preoperative weakness of the involved limb in extension and internal rotation recovered in the male patients, but not in the female patients after postoperative rehabilitation. The peak torque of the involved limb in internal rotation was decreased in the STG group, but not in the ST group. Conclusions: The internal rotational torque was influenced by harvesting the semitendinosus and gracilis tendons after ACL reconstruction, especially in female patients and patients from whom the gracilis tendon was harvested. Semitendinosus and gracilis tendons are important for the internal rotation of the limb and it was difficult to compensate for this function. Thus, we recommend harvesting the semitendinosus tendon only if tendon quality is sufficient to further minimize harvesting morbidity.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 2 (February), 2002: pp 177–182     

Semitendinosus tendon regeneration after anterior cruciate ligament reconstruction: can we use it twice?

Purpose

It has been demonstrated that the semitendinosus tendon can regenerate after being harvested in its whole length and thickness for anterior cruciate ligament (ACL) reconstruction. Ultrasound studies and guided biopsies of the regenerated tendon have shown compatibility and resembling features of the normal tendon. The question is if this neo-tendon is biologically and functionally adequate for re-use?

Methods

Two randomised groups of 150 volunteers were followed up for two years after harvesting the semitendinosus only (25) or the semitendinosus and gracilis tendons (25) in ACL reconstruction. The patients were followed up with clinical and ultrasound examinations, biopsies and histological tests. Surgical exploration was done in three patients for macroscopic verification. The injected arteries of four lower limbs were dissected and the tendon’s arterial supplies were examined.

Results

Seventy-two percent of the cases showed regeneration of the semitendinosus tendons. The neotendons were inserted mostly below the knee joint (83.3 %) where they had fused with the gracilis tendon, and above the joint (60 %) when the gracilis was harvested as well. The isokinetic strength of the hamstrings and quadriceps was not significantly diminished on the operated side. A macroscopic and histological analysis of the regenerated tendons demonstrates close resemblance to normal anatomy, with focal areas of fibrosis. In one patient the regenerated tendon was used for medial patellofemoral ligament reconstruction.

Conclusion

The semitendinosus muscle can recover and the tendon has great potential to regenerate after harvesting for ACL reconstruction. Our data suggest that the regenerated tendons could be used for iterative ligament reconstruction.     

A comparison of outcomes at 2 to 6 years after acute and chronic anterior cruciate ligament reconstructions using hamstring tendon grafts

Purpose: To compare short- to intermediate-term outcomes of patients in whom an acute or chronic anterior cruciate ligament (ACL) reconstruction was performed with a hamstring tendon graft. Type of Study: A consecutive case series of patients who had 2-incision, arthroscopically assisted ACL reconstructions with a triple-strand hamstring tendon graft was retrospectively evaluated. Methods: A total of 120 patients were evaluated at a mean of 44 months. The Tegner Activity Scale, individual components of the Cincinnati Knee Rating System, and the modified Lysholm Score were administered to all patients. A total of 93 patients (78%) returned for examination, instrumented ligament laxity testing, radiographs, isokinetic strength testing, and completion of the IKDC Standard Knee Ligament Evaluation Form. Data from patients undergoing reconstructions for acute and chronic ACL deficiencies were compared. The acute group was defined as reconstruction within 6 weeks of injury without recurrent episodes of instability. Results: At surgery, significantly more (P <.05) cartilage abnormalities and partial medial menisectomies were found in the chronic group. At final follow-up, no significant differences (P >.05) were found between the acute and chronic groups for instrumented laxity, muscle strength, knee motion, or sports activity level. The acute group scored significantly higher (P <.05) on the Lysholm scale, Cincinnati Function scale, IKDC subjective assessment, and IKDC rating for pain at follow-up. The final IKDC grade resulted in significantly more (P =.039) normal knees for the acute group; however, 94.1% of acute and 92.9% of chronic knees were graded normal or nearly normal. Conclusions: Hamstring tendons are an excellent graft choice for ACL reconstruction in both acute and chronic injuries. According to the strict IKDC rating system, greater than 90% of all patients can be expected to have a normal or nearly normal knee at short- to intermediate-term follow-up; however, the chronic group will have fewer patients with a rating of normal.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 4 (April), 2001: pp 383–392     

Atrophy of semitzendinosus and gracilis and flexor mechanism function after hamstring tendon harvest for anterior cruciate ligament reconstruction

The cross-sectional areas of individual knee flexors and isokinetic flexion measurements were evaluated using computed tomography in 13 patients following semitendinosus and gracilis tendon harvest for anterior cruciate ligament reconstruction. The atrophy of tendon-dissected muscles demonstrated variance with two peaks: >70% and <50%. In three patients whose semitendinosus and gracilis muscles displayed areas <50% of the contralateral area, the cross-sectional area of the entire flexor group and work at >75 degrees of knee flexion was 88.1% and 51.9%, respectively. Therefore, hamstring tendon harvest can induce atrophy of tendon-dissected muscles and decrease flexor function.     

Patellar tendon versus quadrupled bone-semitendinosus anterior cruciate ligament reconstruction: a prospective clinical investigation in athletes

Purpose:Patellar tendon and hamstrings are both used in anterior cruciate ligament (ACL) reconstruction, and comparisons have been reported with different results. The purpose of this clinical study was to compare the results of ACL reconstruction in athletes with 2 different graft types, both using bone-to-bone healing: bone-patellar tendon-bone graft and a quadrupled bone-semitendinosus graft.Type of Study:Outcomes study.Methods:From 1994 to 1997, 2 groups of 40 athletes who underwent ACL replacement with patellar tendon and quadrupled bone-semitendinosus grafts were prospectively evaluated. Preinjury activity level, age, and gender were comparable in both groups. All patients were operated on by the same surgeon within 5 months from injury and underwent group-specific rehabilitation programs. An independent examiner performed the final evaluations at 36 months. Review included clinical examination, radiographs, computed analysis, isokinetic and functional strength tests, and subjective and objective evaluation with standard knee scores. Additional procedures were recorded. Statistical analysis was performed with both parametric and nonparametric tests.Results:Average surgical time was longer with the semitendinosus graft, and postoperative pain was higher in the patellar tendon group. Standard knee evaluation scores and subjective assessment revealed no significant differences. Isokinetic testing of flexion-extension and internal-external rotation showed lower quadriceps strength and a mild deficit of external rotation in the patellar tendon group and slightly lower flexor strength in the semitendinosus group at 12 months. Computerized laxity analysis showed no difference between the 2 groups with 90% of patients having less than 3 mm side-to-side difference, with a gender difference in the semitendinosus group. Kneeling pain was higher in patellar tendon group.Conclusions:The bone-patellar tendon-bone and quadrupled bone-semitendinosus autograft provide excellent grafts for ACL reconstruction. Both techniques are comparable regarding final stability, but in patients with extensor mechanism problems or those who engage in sports with a high incidence of patellar tendonitis, the semitendinosus graft should be considered.     

Arthroscopically assisted combined anterior and posterior cruciate ligament reconstruction in the multiple ligament injured knee: 2- to 10-year follow-up

Purpose: This study presents the 2- to 10-year results of 35 arthroscopically assisted combined anterior cruciate ligament and posterior cruciate ligament (ACL/PCL) reconstructions evaluated preoperative and postoperatively using Lysholm, Tegner, and Hospital for Special Surgery knee ligament rating scales, KT-1000 arthrometer testing, stress radiography, and physical examination. Type of Study: Case series. Methods: This study population included 26 men and 9 women with 19 acute and 16 chronic knee injuries. Ligament injuries included 19 ACL/PCL/posterolateral instabilities, 9 ACL/PCL/medial cruciate ligament (MCL) instabilities, 6 ACL/PCL/posterolateral/MCL instabilities, and 1 ACL/PCL instability. All knees had grade III preoperative ACL/PCL laxity and were assessed preoperatively and postoperatively with arthrometer testing, 3 different knee ligament rating scales, stress radiography, and physical examination. Arthroscopically assisted combined ACL/PCL reconstructions were performed using the single-incision endoscopic ACL technique and the single femoral tunnel–single bundle transtibial tunnel PCL technique. PCLs were reconstructed with allograft Achilles tendon (in 26 cases), autograft bone–patellar tendon–bone (BPTB) (in 7 cases), and autograft semitendinosus/gracilis (in 2 cases). ACLs were reconstructed with autograft BPTB (16 cases), allograft BPTB (12 cases), Achilles tendon allograft (6 cases), and autograft semitendinosus/gracilis (1 case). MCL injuries were treated with bracing or open reconstruction. Posterolateral instability was treated with biceps femoris tendon transfer, with or without primary repair, and posterolateral capsular shift procedures as indicated. Results: Postoperative physical examination revealed normal posterior drawer/tibial step-off in 16 of 35 (46%) knees. Normal Lackman and pivot-shift test results were found in 33 of 35 (94%) knees. Posterolateral stability was restored to normal in 6 of 25 (24%) knees, and tighter than normal knee results were found in 19 of 25 (76%) knees evaluated with the external rotation thigh foot angle test. In this group, 30° varus stress testing was normal in 22 of 25 (88%) knees, and grade 1 laxity was found in 3 of 25 (12%) knees. 30° valgus stress testing was normal in 7 of 7 (100%) surgically treated MCL tears, and in 7 of 8 (87.5%) brace-treated knees. Postoperative KT-1000 arthrometer testing mean side-to-side difference measurements were 2.7 mm (PCL screen), 2.6 mm (corrected posterior), and 1.0 mm (corrected anterior) measurements, a statistically significant improvement from preoperative status (P = .001). Postoperative stress radiographic side-to-side difference measurements measured at 90° of knee flexion and 32 lb posteriorly directed proximal force were 0 to 3 mm in 11 of 21 (52.3%) knees, 4 to 5 mm in 5 of 21 (23.8%), and 6 to 10 mm in 4 of 21 (19%) knees. Postoperative Lysholm, Tegner, and HSS knee ligament rating scale mean values were 91.2, 5.3, and 86.8, respectively, showing a statistically significant improvement from preoperative status (P = .001). Conclusions: Combined ACL/PCL instabilities can be successfully treated with arthroscopic reconstruction and the appropriate collateral ligament surgery. Statistically significant improvement is noted from the preoperative condition at 2- to 10-year follow-up using objective parameters of knee ligament rating scales, arthrometer testing, stress radiography, and physical examination. Postoperatively, these knees are not normal, but they are functionally stable. Continuing technical improvements will probably improve future results.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 7 (September), 2002: pp 703–714     

The effect of initial graft tension on postoperative clinical outcome in anterior cruciate ligament reconstruction with semitendinosus tendon.

Introduction: The goal of this study is to establish the influence of tensioning the graft during anterior cruciate ligament (ACL) reconstruction, with a semitendinosus tendon graft, on postoperative stability. Type of study: Prospective controlled clinical trial. Material and methods: Forty-eight patients were randomly allocated to three groups in which three different tensions, 8, 12, or 15 kg force, was applied on the reconstructed ACL during the operation. The patients were observed for 1 year or more after surgery (min. 1 year, max. 2 years 8 months). Clinical outcome was evaluated using the visual analogue scale, anterior knee laxity (using the KT2000 arthrometer) and the torque of the knee extensor. Results: Postoperatively, the average side-to-side differences in anterior laxity were 1.3 mm in the 8 kg group, 2.1 mm in the 12 kg, and 2.4 mm in the 15 kg group. The visual analogue scale averaged 84, 83, and 79 mm, respectively. There were no significant differences among the three groups. There were also no significant differences between the groups for muscle strength recovery during isokinetic and isometric contraction at 1 year postoperatively. Conclusion: There were no significant differences among the groups in subjective clinical results, anterior laxity, and knee extensor strength in the ACL reconstructions that used the autogenous semitendinosus tendon graft.     

Prospective clinical comparisons of semitendinosus versus semitendinosus and gracilis tendon autografts for anatomic double-bundle anterior cruciate ligament reconstruction

Background

The data available from the previously reported clinical studies remains insufficient concerning the hamstring graft preparation in double-bundle anterior cruciate ligament (ACL) reconstruction.

Objective

To test the hypothesis that there are no significant differences between the semitendinosus tendon alone and the semitendinosus and gracilis tendon graft fashioning techniques concerning knee stability and clinical outcome after anatomic double-bundle ACL reconstruction.

Methods

A prospective study was performed on 120 patients who underwent anatomic double-bundle ACL reconstruction according to the graft fashioning technique. The authors developed the protocol to use hamstring tendon autografts. When the harvested doubled semitendinosus tendon is thicker than 6 mm, each half of the semitendinosus tendon is doubled and used for the anteromedial (AM) and posterolateral (PL) bundle grafts (Group I). On the other hand, when the harvested semitendinosus tendon is under 6 mm in thickness, the gracilis tendon is harvested additionally. The distal half of the semitendinosus and gracilis tendons are doubled and used for the AM bundle graft, and the remaining proximal half of the semitendinosus tendon is doubled and used for the PL bundle grafts (Group II). Sixty-one patients were included in Group I, and 59 patients in Group II. The two groups were compared concerning knee stability and clinical outcome 2 years after surgery.

Results

The postoperative side-to-side anterior laxity averaged 1.3 mm in both groups, showing no statistical difference. There were also no significant differences between the two groups concerning the peak isokinetic torque of the quadriceps and the hamstrings, the Lysholm knee score, and the International Knee Documentation Committee evaluation.

Conclusion

There were no significant differences between the two graft fashioning techniques after anatomic double-bundle ACL reconstruction concerning knee stability and postoperative outcome. The present study provided orthopedic surgeons with important information on double-bundle ACL reconstruction with hamstring tendons.

Level of evidence

Level II; prospective comparative study.     

Nonunited avulsion fractures of the intercondylar eminence of the tibia

Summary: We report 3 cases of nonunited avulsion fracture of the intercondylar eminence of the tibia. Characteristics of the clinical symptoms were limitation of knee extension, pain at knee extension, and a small amount of anterior instability. For the patient with a normal anterior cruciate ligament (ACL), the fragment was fixed by sutures with a button after curettage of the fibrous tissue. Two patients underwent endoscopic ACL reconstruction using quadrupled semitendinosus tendon because their ACLs had degenerated. Since the technique of ACL reconstruction under arthroscopic control has been well refined, endoscopic ACL reconstruction is considered to be 1 of the surgical options for nonunited avulsion fracture with symptomatic anterior instability if the ACL is degenerated.Arthroscopy: The Journal of Arthroscopic and Related surgery, Vol 16, No 7 (October), 2000: pp 757–762     

Anterior cruciate ligament reconstruction in patients with or without accompanying injuries: A re-examination of subjects 5 to 9 years after reconstruction

Purpose: The purpose of this study was to compare the clinical and radiologic results of an anterior cruciate ligament (ACL) reconstruction in patients with an isolated ACL tear and patients with an ACL tear and accompanying injuries. Type of Study: A retrospective investigation. Methods: Seventy-two patients who did not have previous knee surgery or surgery of the contralateral knee were re-examined 5 to 9 years after the primary ACL reconstruction. The clinical assessment was made using the International Knee Documentation Committee (IKDC) evaluation system, and the Lysholm and the Marshall knee scores. Also, radiographic evaluation and isokinetic strength testing were performed. There were 34 patients (25 men and 9 women) with an isolated ACL tear (group A), and 38 patients (23 men and 15 women) with an ACL tear and accompanying injuries (group B). The mean age was 29 years (SD 9; range, 15 to 49 years) in group A, and 34 years (SD 12; range, 15 to 61 years) in group B. Bone–patellar tendon–bone autograft with mini-arthrotomy technique and screw fixation was used in all patients. Postoperative rehabilitation was also similar in both groups. In group B, 10 medial and 12 lateral (partial or subtotal) arthroscopic meniscectomies were performed at the same time as the ACL reconstruction. Also, 18 of the 19 medial collateral ligament ruptures, the 2 lateral collateral ligament ruptures, and the 1 posterior cruciate ligament rupture were treated surgically at this operation. Results: Subjectively (overall assessment, pain, swelling, and giving way of the knee) and objectively (range of motion, stability, crepitation, isokinetic strength testing, and radiological changes of the knee), the groups did not have any significant differences in the 5- to 9-year results. Also, the final evaluation results using the IKDC and the Lysholm and the Marshall knee scores were similar in both groups. However, there were significantly more subsequent knee surgeries in the injured knee in group B than in group A. Conclusions: Our results show no large differences between patients with an isolated ACL tear and those with an ACL tear with accompanying injuries 5 to 9 years after an ACL reconstruction with a bone–patellar tendon–bone autograft. Tibiofemoral osteoarthritis was quite rare, and this may be partly attributable to the fact that the ACL reconstructions were successful, so that all the knees were stable at the re-examination. However, the future will show the final outcome for the patients.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 8 (October), 2001: pp 818–825     

Isokinetic evaluation of anterior cruciate ligament reconstruction: hamstring versus patellar tendon.

The purpose of the study was to compare the hamstring and quadriceps isokinetic results 6 months postoperatively in patients having patellar tendon or hamstring anterior cruciate ligament (ACL) reconstruction. The study group was comprised of 106 randomly selected patients who had ACL reconstruction with either autogenous patellar tendon (PT), semitendinosus (ST), or semitendinosus and gracilis (ST/G). Hamstring and quadriceps isokinetic strength were assessed at 180 degrees/sec and 300 degrees/sec with the results of the operatively treated leg expressed as a percent compared with the nonoperative leg. The mean results for knee extension at 180 degrees/sec were 68.3%, 74.3%, and 78.1%; and at 300 degrees/sec were 70.7%, 76.7%, and 81.7% for PT, ST, and ST/G, respectively. The mean results for knee flexion at 180 degrees/sec were 86.1%, 80.6%, and 81.7%; and at 300 degrees/sec were 77.6%, 79.1%, and 75.6% for PT, ST, and ST/G, respectively. No statistically significant differences were found in regard to knee extension or flexion strength when evaluating the different tissue sources. The results show that selection of autogenous hamstring or PT used for ACL reconstruction should not be based solely on the assumption of the tissue source altering the recovery of quadriceps and/or hamstring strength. In addition, a majority of the patients had not achieved adequate strength to safely partake in unlimited activities at 6 months postoperatively.     

Effects of knee immobilization on morphological changes in the semitendinosus muscle–tendon complex after hamstring harvesting for anterior cruciate ligament reconstruction: evaluation using three-dimensional computed tomography

Background  

It is desirable to maintain the morphology of the semitendinosus muscle–tendon complex after tendon harvesting for anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to evaluate the effect of knee immobilization on morphological changes in the semitendinosus muscle–tendon complex.     

Comparison of sagittal obliquity of the reconstructed anterior cruciate ligament with native anterior cruciate ligament using magnetic resonance imaging

Purpose: This study was conducted to compare the obliquity of asymptomatic anterior cruciate ligament (ACL) grafts with normal controls using sagittal magnetic resonance imaging (MRI). Type of Study: Case control study. Methods: Sagittal MRIs from 30 patients with a reconstructed ACL graft and from 30 individuals with an intact ACL were reviewed. Reconstructed patients were operated on with a 2-incision technique using a patellar tendon autograft. These selected patients had a normal or nearly normal IKDC score with a 3 mm or less anterior posterior translation on KT-1000 arthrometer testing compared with the intact knee. MRI showed a continuous and homogeneous graft without evidence of roof impingement. Obliquity of the grafted ACL was determined on each lateral MRI by measuring the intersection of the graft line with the tibial plateau plane. These figures were compared with data similarly obtained from 30 individuals with a stable knee and an intact ACL determined by history and physical examination. Results: Graft obliquity in reconstructed patients averaged 67° with a range between 55° and 81°. In normal controls, intact ACL obliquity averaged 51° with a range between 45° and 55°. The difference between the two groups was statistically significant (P <.0001). Conclusions: MRIs of patients with an appropriate tibial tunnel placement in order to avoid notch impingement showed a continuous and homogeneous graft similar to the native ACL, but with a more vertical graft that does not recreate the normal sagittal obliquity. However, according to arthrometer testing, these more vertical grafts can control anterior posterior knee displacement.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 19, No 3 (March), 2003: pp 257–261     

Pulley system isokinetic training in knee rehabilitation--initial results

AIM: The purpose of this study was to evaluate the results of a knee rehabilitation program after knee surgery, based on an isokinetic pulley System (Moflex, Recotec/Bernina, Switzerland). METHOD: In this prospective study, 73 patients participated in a standardized rehabilitation program (ACL reconstruction, ACL/all: n = ;51; patellar tendon, ACL/P: n = 30; semitendinosus tendon, ACL/S: n = 21; arthroscopic meniscus resection: n = 22). The major aspect of the program was an isokinetic pulley system with an implemented, linearly working knee device. RESULTS: Isokinetic training with the used device affords strict monitor feed-back to avoid critical torque values. Concentric training strength and workload which were attained without relevant pain were increased by about 130% within a mean of 16 rehabilitation days. At the end of the rehabilitation program, the maximum concentric strength of the affected knee measured by a rotating isokinetic system (Cybex, Kaphingst, Lahntal) increased by about 69% and amounted to about 90% of that of the unaffected knee. CONCLUSION: These first results demonstrate the value of the isokinetic pulley system in the rehabilitation after knee surgery as described above. The equipment may be used already in an early postoperative stage by the use of a passive or active-assistive mode. First results of strength increases using an isokinetic pulley system in knee rehabilitation are presented.     

Quantitative Analysis of Patellar Tendon After Total Knee Arthroplasty Using Echo Intensity: A Nonrandomized Controlled Trial of Alpine Skiing

BackgroundDespite the knee extensor weakness, less attention has been paid to the evaluation of patellar tendon after total knee arthroplasty (TKA). We previously observed patellar tendon hypertrophy after TKA. The purpose of this study is to reanalyze these ultrasound data to detect whether brightness mode ultrasound imaging reflects pathological changes of the patellar tendon after TKA.MethodsTwenty-eight participants with post unilateral TKA were assigned to an intervention group or control group. The intervention group underwent a 12-week skiing program. Patellar tendon mechanical properties were obtained by combining isometric dynamometry, ultrasound imaging, and electromyography in operated knee and nonoperated knee. Luminosity ratio (LR) was measured using echo intensity in a relaxed and maximally loaded phase.ResultsBaseline comparisons revealed significant effects of the surgical side (P < .001) and loading phase (P = .017), but no interaction between leg and phase (P < .149). LR of the operated knee was significantly lower than LR of the nonoperated knee in relaxed (P < .001) and maximally loaded phases (P = .003). In addition, there was a significant correlation between LR of maximum phase and isometric knee extension torque (r² = 0.156, P = .038). However, LR was not related to patellar tendon stiffness, Young’s modulus, or strain. There was a significant time effect in knee extension torque, but no time effects on LR and tendon force.ConclusionPatellar tendon LR is decreased along with degenerative change after TKA. Ultrasound imaging provides a promising metric to acquire in vivo patellar tendon pathological assessment after TKA.     

Single- versus bi-socket anterior cruciate ligament reconstruction using autogenous multiple-stranded hamstring tendons with EndoButton femoral fixation: A prospective study

Purpose: This prospective study was conducted to compare the single-socket and the bi-socket anterior cruciate ligament (ACL) reconstruction techniques in terms of outcome. Type of Study: Nonrandomized control trial. Methods: There were 160 consecutive patients with unilateral chronic ACL insufficiency who underwent endoscopic single- or bi-socket ACL reconstruction alternately using multiple-stranded medial hamstring tendon and EndoButton (Smith & Nephew, Andover, MD) femoral fixation. All patients underwent the same postoperative rehabilitation protocol. Of them, 106 patients (57 single, 49 bi) were available for 2-year follow-up. Results: According to the IKDC Knee Ligament Evaluation Form, 23 patients (40%) of the single-socket group were subjectively graded as normal, 30 (53%) as nearly normal, and 4 (7%) as abnormal. Twenty-six patients (53%) of the bi-socket group were graded as normal, 21 (43%) as nearly normal, and 2 (4%) as abnormal (P =.19). The mean side-to-side anterior laxity difference (KT-1000 manual maximum force) was 0.9 ± 1.8 mm for the single-socket group and 0.7 ± 1.2 mm for the bi-socket group (P =.44). Fifty-three of 57 patients (93%) in the single-socket group and all patients in the bi-socket group showed anterior laxity differences of ±3 mm or less (P =.12). There were no differences in thigh muscle strength between the groups. Conclusions: Both single- and bi-socket ACL reconstruction using autogenous multiple-stranded hamstring tendons with EndoButton fixation provided satisfactory anterior stability, and there were no statistically significant differences in subjective results or measured restored stability between the 2 groups.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 8 (October), 2001: pp 801–807     

Proprioception of the knee before and after anterior cruciate ligament reconstruction

Purpose: The purpose of this study was to determine, first, if there is measurable deficit in proprioception in an anterior cruciate ligament (ACL)-deficient knee, either compared to the contralateral knee or external controls; second, if this deficit, if present, improves after ACL reconstruction; and third, if improvement occurs, what the time course of improvement is. Type of Study: Prospective cohort study. Methods: Patients undergoing ACL reconstruction at the University of Chicago, demonstrating a full and painless range of motion and no other knee ligament injury or history of previous knee surgery, were eligible. Twenty-six patients, with an average age of 25 years (range, 16 to 48) were enrolled. Average time from injury to reconstruction was 8 weeks. The patients' contralateral knee served as an internal control, and 26 age-matched and gender-matched healthy volunteers were enrolled as an external control group. ACL reconstructions were performed using a single-incision technique with either bone–patellar tendon–bone or quadrupled hamstring autograft. They were allowed immediate weightbearing as tolerated and participated in a standardized rehabilitation program, with the goal of returning to sport at approximately 6 months. Proprioception testing was carried out using an electrogoniometer, in a seated position. Joint position sense (JPS) and threshold to detection of passive motion (TDPM) were measured preoperatively and at 3 and 6 weeks and 3 and 6 months postoperatively. Results: Mean KT-2000 values 6 months postoperatively were 1.38 mm (±2). Modified Lysholm score improved significantly (P < .01). Calculated r values were 0.65 for JPS and 0.96 for TDPM. No significant differences in postoperative proprioception were found between hamstring and patellar tendon grafts or among patients with meniscus injury, meniscus repair, or chondral injury. Preoperatively, the mean TDPM in both the injured and contralateral knees was significantly higher (worse) than in the external control knees (P = .008; P = .016). Evaluation of changes in proprioception from preoperative to 6 months postoperative showed significant improvement in both injured and contralateral knees (P = .04; P = .01). At 6-month follow-up, there was no significant difference from controls. Conclusions: TDPM was a more reliable method than JPS for testing proprioception before and after ACL reconstruction in this study. Bilateral deficits in knee joint proprioception (TDPM) were documented after unilateral ACL injury. Reconstruction of a mechanical restraint (ACL graft) was believed to have a significantly positive impact on early and progressive improvement in proprioception.     

Quadrupled semitendinosus anterior cruciate ligament reconstruction: 5-year results in patients without meniscus loss

Purpose: The purpose of this study was to determine the mid-term (minimum 5-year) results of isolated primary anterior cruciate ligament (ACL) reconstructions with intact or repaired menisci. Type of Study: Case series. Methods: Of 184 ACL reconstructions from April 1990 to February 1992, 33 initially met the inclusion criteria of primary reconstruction with quadrupled semitendinosus tendon and without extra-articular reconstruction or meniscus removal. Patients with known traumatic rerupture of the graft with revision (1 case) or subsequent meniscectomy (1 case) were excluded from the study. Twenty of the remaining 31 patients were available for follow-up at an average of 5.7 years after surgery. At follow-up, a comprehensive knee examination, KT-1000 arthrometry, radiography, functional testing, and isokinetic strength testing were performed. A subjective questionnaire, Tegner scale, and IKDC evaluation were administered as well. Four patients who were unable to come in for follow-up returned a knee-assessment questionnaire. Results: Arthrometric anterior tibial translation was reduced from a preoperative average of 6.3 ± 2.8 mm (manual maximum side-to-side difference) to an average of 0.0 ± 1.3 mm (range, −2.5 to 2 mm). Radiographically, 1 patient experienced mild narrowing in the lateral compartment. Tegner activity level was maintained at the preinjury level in nearly half the patients. Isokinetic strength deficits were less than 10%; 17 (85%) of the patients had a normal or nearly normal result as graded by the IKDC scoring system. Conclusions: The above data show minimal morbidity, a low reoperation rate, and excellent clinical outcome. Because the stability of the knee persists beyond 5 years after ACL reconstruction, patients are able to maintain preinjury activity levels without reinjury.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 8 (October), 2001: pp 795–800