Graft failure in intra-articular anterior cruciate ligament reconstructions: a review of the literature

Femoral tunnel enlargement after anatomic ACL reconstruction: a biological problem?

Tunnel enlargement after anterior cruciate ligament (ACL) reconstruction may compromise revision surgery. The cause of this tunnel enlargement is not yet fully understood, but it is thought to be multifactorial, with biomechanical and biological factors playing a role. Tunnel enlargement has been described particularly in patients who underwent ACL reconstruction with hamstring tendons with extracortical fixation devices. The purpose of our study was to evaluate prospectively with magnetic resonance imaging (MRI) the changes in femoral tunnel diameter following arthroscopic anatomic ACL reconstruction with hamstring tendons. At 3-month post-op, all tunnels had enlarged compared to the diameter of the drill and most tunnels enlarged more in the midsection than at the aperture. In the posterolateral tunnels, the entrance increased 16% in diameter and the middle of the tunnel increased 30% in diameter. In the anteromedial femoral tunnels, the tunnels enlarged 14% at the aperture and 35% in the midsection. All femoral tunnels enlarged and most of them enlarged in a fusiform manner. The biological factors explain better our findings than the mechanical theory, although mechanical factors may play a role and the cortical bone at the entrance of the tunnel may modify the way tunnels respond to mechanical stress.

Biology and augmentation of tendon-bone insertion repair

Surgical reattachment of tendon and bone such as in rotator cuff repair, patellar-patella tendon repair and anterior cruciate ligament (ACL) reconstruction often fails due to the failure of regeneration of the specialized tissue ("enthesis") which connects tendon to bone. Tendon-to-bone healing taking place between inhomogenous tissues is a slow process compared to healing within homogenous tissue, such as tendon to tendon or bone to bone healing. Therefore special attention must be paid to augment tendon to bone insertion (TBI) healing. Apart from surgical fixation, biological and biophysical interventions have been studied aiming at regeneration of TBI healing complex, especially the regeneration of interpositioned fibrocartilage and new bone at the healing junction. This paper described the biology and the factors influencing TBI healing using patella-patellar tendon (PPT) healing and tendon graft to bone tunnel healing in ACL reconstruction as examples. Recent development in the improvement of TBI healing and directions for future studies were also reviewed and discussed.

Anatomic double-bundle versus single-bundle ACL reconstruction: a comparative biomechanical study in rabbits

Thirty New Zealand white rabbits underwent anterior cruciate ligament (ACL) reconstruction in their right knees; 15 animals underwent a double-bundle anatomic ACL reconstruction using the medial third of the patellar tendon and the semitendinosus tendon. Additionally, 15 animals underwent ACL reconstruction, using a single-bundle semitendinosus tendon autograft. The knees of both groups were evaluated with a device similar to the KT1000 arthrometer onto which a dial indicator was attached (Mitutoyo dial indicator 2050) in 30 degrees and 90 degrees of flexion, preoperatively, after ACL resection and 3 months postoperatively. Statistical analysis of the results revealed that for 90 degrees of knee flexion, the mean estimated anterior shift for the double-bundle technique was 1.92 mm lesser than that of the single-bundle technique (P = 0.006). For 30 degrees of knee flexion, the mean anterior shift was again lesser than that of the single-bundle technique by 0.66 mm, but this difference was not statistically significant. The described double-bundle ACL reconstruction technique resulted in a more stable knee as far as the anterior tibial shift was concerned as compared to a single-bundle ACL reconstruction. This animal model may be potentially useful in the future for the study of other parameters influencing the outcome of the double-bundle ACL reconstruction.

Repeat revision of anterior cruciate ligament reconstruction: a retrospective review of management and outcome of 10 patients with an average 3-year follow-up

BACKGROUND

To the authors' knowledge, no previous published study has focused on management and outcome of repeat revision of anterior cruciate ligament reconstruction in terms of functional result and meniscus and articular cartilage status.

HYPOTHESIS

Repeat revision of anterior cruciate ligament reconstruction improves knee stability, but with inferior results for functional outcome compared with primary anterior cruciate ligament reconstruction. Meniscal tears and subsequent articular cartilage degeneration are more prevalent with successive revisions due to recurrent laxity.

STUDY DESIGN

Case series; Level of evidence, 4.

MATERIALS AND METHODS

Between February 2003 and November 2006, a consecutive series of 10 patients with an average age at 30 years (range, 17-48) were operated on for a repeat revision of anterior cruciate ligament reconstruction (2 revisions after a primary reconstruction) with arthroscopic procedures. A clinical and a radiographic evaluation were performed to assess anterior cruciate ligament reconstruction failures, outcome of revisions, and causes of failures. Meniscal tears and articular cartilage lesions were analyzed.

RESULTS

The average follow-up of the second revision was 38 months (range, 12-61). At latest follow-up, final International Knee Documentation Committee assessment was excellent or good in 7 cases. Postoperatively, only 2 patients recovered to the same sports activity level they had before their first anterior cruciate ligament reconstruction. Four had a lower level, and 4 discontinued sports activity. The postoperative average side-to-side KT-1000 arthrometer maximum manual difference was 1.3 +/- 1.9 mm. Nine patients had meniscal tears and 7 had articular cartilage lesions. Meniscal tears, meniscectomies, and articular cartilage degeneration increased after the second revision (P = .016, P = .0098, and P = .0197, respectively). Severe articular cartilage degeneration (International Cartilage Repair Society grade III and IV lesions) was found in patients with bad functional outcome (final International Knee Documentation Committee assessment C or D) (P = .0472). Incidence of articular cartilage degeneration was found to be more prevalent in cases of meniscal tears and partial meniscectomy at the same tibiofemoral compartment (P = .0157). Index anterior cruciate ligament reconstruction and first revision failures were caused by recurrent trauma (60% and 70%, respectively) or a surgical technical error with tunnel malpositioning (40% and 10%, respectively).

CONCLUSION

Outcome of repeat revision of anterior cruciate ligament reconstruction was excellent or good in 70% of the cases, although decreased after the second revision, in relation to the occurrence of meniscal tears and articular cartilage lesions. Meniscal and articular cartilage lesions were more frequent and more severe with recurrent laxity. The cause of failures was mainly recurrent trauma, followed by surgical technical errors.

Histological evaluation of the healing potential of the anterior cruciate ligament by means of augmented and non-augmented repair: an in vivo animal study

The purpose of this animal study was to investigate the healing potential of the anterior cruciate ligament following transaction at the femoral end, by means of both the augmented and the nonaugmented primary repair, focusing on the histological changes during a 12-month postoperative observation period with respect to necrosis and the loss of normal structures during the healing period. Twenty sheep were randomly assigned to nonaugmented primary ACL repair, or to augmented ACL repair using a polyethylene terephthalate (PET) band. At 2, 6, 16, 26 and 52 weeks postoperatively four sheep out of each group were sacrificed. Histological healing was achieved after 16 weeks for the augmented repair group and after 26 weeks for the nonaugmented repair group. The main difference between the two techniques was that the PET augmentation device protected the ligament from necrosis and ligamentization. In this group a consistently normal ligament was seen histologically during the entire postoperative observation period. The nonaugmented repaired ACLs underwent the processes of necrosis and ligamentization.

Tunnel enlargement after anterior cruciate ligament reconstruction in patients with post-operative septic arthritis

Tunnel enlargement is a frequent issue after ACL reconstruction and the "synovial bathing effect" is thought to be among the biological factors contributing to this phenomenon. Since the amount and the pressure of the synovial fluid inside the knee joint are higher and the length of its presence is longer in patients with post-operative septic arthritis after ACL reconstruction, we reviewed the tunnel enlargement in these cases in order to better evaluate this phenomenon in such a hostile environment. The null hypothesis of this study was that the highly represented phenomenon of the "synovial bathing effect" that occurs in an infected ACL reconstruction would not affect the amount of post-operative tunnel widening. A case-control study was done. At a mean follow up of 10 months (range 9-11 months) eight patients with septic arthritis following ACL reconstruction (group A) were radiologically reviewed using a CT scan and the diameters of femoral and tibial tunnels were measured. The results were compared with a control group (B) of uncomplicated ACL reconstruction cases operated by the same surgeon using the same technique. Although patients of Group A experienced a bigger amount of tunnel enlargement than patients of group B both on femoral (9.53 +/- 1.07 vs. 9.35 +/- 1.52 mm) and tibial side (10.07 +/- 1.3 vs. 9.92 +/- 0.74 mm), no clinical or statistically significant differences were detected between the groups (P > 0.05). No significant tunnel enlargement could be detected in patients of group A when compared with patients of group B. This seems to minimize the role of biological factors contributing to tunnel widening.

Anterior cruciate ligament reconstruction grafts: MR imaging features at long-term follow-up--correlation with functional and clinical evaluation

PURPOSE

To assess the presence of increased intrasubstance signal intensity within anterior cruciate ligament (ACL) grafts and to assess whether such signal intensity changes are correlated to clinical assessments of graft instability and patient function 4-12 years after ACL reconstruction.

MATERIALS AND METHODS

Ethical permission and written informed patient consent were obtained. The study was HIPAA compliant. Forty-seven patients were included and underwent 1.5-T magnetic resonance (MR) imaging of the knee that was treated surgically. Signal intensity characteristics of the ACL graft were evaluated on sagittal intermediate-weighted and sagittal and axial T2-weighted fast spin-echo MR images. The amount of signal intensity change, femoral and tibial graft tunnel position, and orientation of ACL graft in the coronal plane were assessed. Objective index of graft stability or laxity was performed with arthrometric testing, and subjective function was assessed by using International Knee Documentation Committee (IKDC) scoring.

RESULTS

Increased intrasubstance graft signal intensity was found in 70 % (33 of 47) and in 64% (30 of 47) of patients on intermediate-weighted MR images and T2-weighted MR images, respectively. When present, intrasubstance graft signal intensity changes involved less than 25% of the maximal cross-sectional area of the graft in 70% (23 of 33) of cases on intermediate-weighted acquisitions and in 70% (21 of 30) of cases on T2-weighted acquisitions. No significant association was seen between graft signal intensity changes on intermediate-weighted and T2-weighted images and IKDC score (P = .667 and .698, respectively), arthrometric testing (P = .045-.99), and time since surgery (P = .592 and .610, respectively).

CONCLUSION

Small amounts of increased intrasubstance graft signal intensity on intermediate- and T2-weighted images can be seen after ACL reconstruction at long-term follow-up of 4 years or longer and do not necessarily correlate with findings of joint instability or functional limitations in patients after ACL repair.

Revision anterior cruciate ligament reconstruction with doubled semitendinosus and gracilis tendons and lateral extra-articular reconstruction. Surgical technique

BACKGROUND

The outcome of revision anterior cruciate ligament reconstruction has only rarely been reported. The purpose of this study was to evaluate the results of revision anterior cruciate ligament surgery with use of an autogenous doubled semitendinosus and gracilis graft in association with an extra-articular procedure.

METHODS

Between 1997 and 2003, thirty patients underwent a repeat reconstruction of a previously reconstructed torn anterior cruciate ligament with use of a doubled semitendinosus and gracilis graft combined with an extra-articular reconstruction. Primary reconstruction had been done with an autogenous patellar tendon graft in twenty-six patients and with a prosthetic ligament in four patients; the average time from the primary reconstruction to the revision was five years. Functional outcomes, graft survival, and radiographic outcomes were evaluated at a mean of five years. A graft was considered to have failed when a revision was done or when the side-to-side difference on KT-1000 arthrometer testing was >5 mm and/or the pivot-shift test grade was greater than a trace.

RESULTS

One patient underwent another revision reconstruction because of graft failure at three years postoperatively. The mean International Knee Documentation Committee (IKDC) subjective knee score for the remaining twenty-nine patients was 84 +/- 12 points, and the mean Lysholm knee score was 90 +/- 10 points. The side-to-side difference as measured with the KT-1000 arthrometer with maximum manual force was <3 mm in twenty patients (of the twenty-eight who returned for follow-up), between 3 and 5 mm in six patients, and >5 mm in two patients. The result of the pivot shift examination was normal in fifteen patients, slightly positive in eleven patients, and positive in two patients. Twenty-five percent of the patients showed no radiographic signs of degenerative joint disease.

CONCLUSIONS

Revision anterior cruciate ligament reconstruction with use of an autogenous doubled semitendinosus and gracilis graft combined with an extra-articular procedure provided satisfactory functional outcomes, with a failure rate of 10%.

Preliminary effects of hyaluronic acid on early rehabilitation of patients with isolated anterior cruciate ligament reconstruction

OBJECTIVE

To investigate the effects of Hyaluronic acid (HA) on early rehabilitation of patients with isolated anterior cruciate ligament (ACL) reconstruction.

DESIGN

Randomized, controlled clinical trial.

SETTING

A total 120 patients with isolated ACL injury who had received patellar tendon autograft reconstruction were randomly assigned to four groups (groups I-IV), with 30 subjects in each group.

INTERVENTIONS

All patients received 16 weeks of a regular rehabilitation program and an intra-articular injection of HA or saline weekly for 3 weeks. Additionally, patients in group I received the HA commencing at 4 weeks after surgery, patients in group II at 8 weeks, and patients in group III at 12 weeks. Patients in group IV did not receive HA but did receive the same volume of normal saline as control subjects at 4 weeks after surgery. The rehabilitation program started at the same time after surgery for all groups.

MAIN OUTCOME MEASUREMENTS

Outcomes were measured at 4, 8, 12, and 16 weeks after reconstruction, and at follow-up 1 year later. These included the changes in Lysholm knee scoring scale, knee range of motion, ambulation speed (AS), and muscle peak torque (MPT) of knee flexion and extension.

RESULTS

There were improvements in groups I-III shortly after receiving the HA, but not in the saline group (group IV). Patients in groups II and III showed more improvement in AS and MPT after rehabilitation program and at follow-up. Besides, the best results 1 year later occurred in the group receiving HA at 8 weeks after surgery (group II).

CONCLUSION

HA therapy results in more functional and MPT improvement in ACL rehabilitation, and the intervention at 8 weeks after surgery results in the best outcome.

Biomechanical evaluation of two techniques for double-bundle anterior cruciate ligament reconstruction: one tibial tunnel versus two tibial tunnels

BACKGROUND

This research was undertaken to determine whether there is a need for a second tibial tunnel in anatomic anterior cruciate ligament reconstruction.

HYPOTHESIS

Anatomic two-bundle reconstruction with two tibial tunnels restores knee anterior tibial translation in response to 134 N and to 5-N.m internal tibial torque combined with 10-N.m valgus torque more closely to normal than does double-bundle reconstruction with one tibial tunnel.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten cadaveric knees were subjected to a 134-N anterior tibial load at 0 degrees, 30 degrees, 60 degrees, and 90 degrees and to 5-N.m internal tibial torque and 10-N.m valgus torque at 15 degrees and 30 degrees. Resulting knee kinematics and in situ force in the anterior cruciate ligament or replacement graft were determined by using a robotic/universal force-moment sensor testing system for (1) intact, (2) anterior cruciate ligament-deficient, (3) double-bundle/one tibial tunnel, and (4) double-bundle/two tibial tunnels.

RESULTS

Anterior tibial translation for the reconstruction with two tibial tunnels was significantly closer to that of the intact knee than was the reconstruction with one tibial tunnel at 0 degrees and 30 degrees of flexion (0 degrees = 3.82 vs 6.0 mm, P < .05; 30 degrees = 7.99 vs 11 mm, P < .05). The in situ force normalized to the intact anterior cruciate ligament for the reconstruction with two tibial tunnels was significantly higher than the in situ force of the reconstruction with one tibial tunnel (30 degrees = 89 vs 82 N, P < .05). With a combined rotatory load, the anterior tibial translation of specimens with a tibial two-tunnel technique was significantly lower than that of specimens with one tunnel (0 degrees = 5.7 vs 8.4 mm, P < .05; 30 degrees = 7.5 vs 9.5 mm, P < .05).

CONCLUSIONS

Anatomic reconstruction with two tibial tunnels may produce a better biomechanical outcome, especially close to extension.

CLINICAL RELEVANCE

At the time of initial fixation, there appears to be a small biomechanical advantage to the second tibial tunnel in the setting of two-bundle anterior cruciate ligament reconstruction.

Double-bundle ACL reconstruction can improve rotational stability

Double-bundle anterior cruciate ligament (ACL) reconstruction reproduces anteromedial and posterolateral bundles, and thus has theoretical advantages over conventional single-bundle reconstruction in controlling rotational torque in vitro. However, its superiority in clinical practice has not been proven. We analyzed rotational stability with three reconstruction techniques in 60 consecutive patients who were randomly divided into three groups (double-bundle, anteromedial single-bundle, posterolateral single-bundle). In the reconstructive procedure, the hamstring tendon was harvested and used as a free tendon graft. Followup examinations were performed 1 year after surgery. Anteroposterior laxity of the knee was examined with a KT-1000 arthrometer, whereas rotatory instability, as elicited by the pivot shift test, was assessed using a new measurement system incorporating three-dimensional electromagnetic sensors. Routine clinical evaluations, including KT examination, demonstrated no differences among the three groups. However, using the new measurement system, patients with double-bundle ACL reconstruction showed better pivot shift control of complex instability than patients with anteromedial and posterolateral single-bundle reconstruction.

Biomechanical testing of hybrid hamstring graft tibial fixation in anterior cruciate ligament reconstruction

Hamstring tendon using quadrupled semitendinosus and gracilis autografts is a well-established technique for ACL reconstruction. However, several methods have been used for tibial fixation of the tendon graft. The purpose of this study was to compare the biomechanical characteristics of quadrupled hamstring graft tibial fixation using three different fixation methods. Nine matched pairs (18 specimens) of cadaver tibias were divided into three groups of six specimens. The first group was fixed with only a tapered 30-mm bioabsorbable screw (BIS), the second group was fixed first with a BIS and then the remaining tendon portion was additionally fixed with a titanium cortical screw and spike washer, and the third group was fixed with only a cortical screw and spike washer. A custom-made probe hook was mounted on a load cell (Interface, MFG, Scottsdale, AZ) to measure the ACL tension before and after the final tibial fixation. Group 2 displayed greater mean maximum load at failure than both groups 1 and 3 (p<0.05). The stiffness of the graft nearly doubled in group 2 compared to groups 1 and 3 (p<0.05). All specimens failed by slippage and pullout. Biomechanical testing with cadavers showed that a BIS and additional cortical screw and spike washer fixation to the distal hamstring tendon resulted in higher load at failure and stiffness compared to either BIS or cortical screw and spike washer fixation alone.

Revision anterior cruciate ligament reconstruction with doubled semitendinosus and gracilis tendons and lateral extra-articular reconstruction

BACKGROUND

The outcome of revision anterior cruciate ligament reconstruction has only rarely been reported. The purpose of this study was to evaluate the results of revision anterior cruciate ligament surgery with use of an autogenous doubled semitendinosus and gracilis graft in association with an extra-articular procedure.

METHODS

Between 1997 and 2003, thirty patients underwent a repeat reconstruction of a previously reconstructed torn anterior cruciate ligament with use of a doubled semitendinosus and gracilis graft combined with an extra-articular reconstruction. Primary reconstruction had been done with an autogenous patellar tendon graft in twenty-six patients and with a prosthetic ligament in four patients; the average time from the primary reconstruction to the revision was five years. Functional outcomes, graft survival, and radiographic outcomes were evaluated at a mean of five years. A graft was considered to have failed when a revision was done or when the side-to-side difference on KT-1000 arthrometer testing was >5 mm and/or the pivot-shift test grade was greater than a trace.

RESULTS

One patient underwent another revision reconstruction because of graft failure at three years postoperatively. The mean International Knee Documentation Committee (IKDC) subjective knee score for the remaining twenty-nine patients was 84 +/- 12 points, and the mean Lysholm knee score was 90 +/- 10 points. The side-to-side difference as measured with the KT-1000 arthrometer with maximum manual force was <3 mm in twenty patients (of the twenty-eight who returned for follow-up), between 3 and 5 mm in six patients, and >5 mm in two patients. The result of the pivot shift examination was normal in fifteen patients, slightly positive in eleven patients, and positive in two patients. Twenty-five percent of the patients showed no radiographic signs of degenerative joint disease.

CONCLUSIONS

Revision anterior cruciate ligament reconstruction with use of an autogenous doubled semitendinosus and gracilis graft combined with an extra-articular procedure provided satisfactory functional outcomes, with a failure rate of 10%.

Influence of the tunnel angle in ACL reconstructions on the biomechanics of the knee joint

BACKGROUND

A high tension in anterior cruciate ligament grafts affects both graft and knee functional performance. Clinical observations suggest that impingement of the graft against the posterior cruciate ligament might cause high graft tensions. Also, meniscal injury has been well documented in association with damage in the anterior cruciate ligament.

METHODS

In this paper, we present the results obtained in a three-dimensional finite element model of the human knee, corresponding to different aspects of anterior cruciate ligament reconstruction with bone-patellar tendon-bone grafts. This model was used to investigate the effect of the angle in the coronal plane of femoral and tibial tunnels. Firstly, graft tension was computed in a knee moved from 0 degrees to 60 degrees of flexion and the results were compared with experimental ones obtained by other authors. Secondly, the resulting kinematics under an anterior load of 134 N was compared to that of the intact knee.

FINDINGS

The obtained results showed that the closest anterior tibial translation to that of the intact knee was obtained with femoral and tibial tunnels with angles of 60 degrees. In this same case, a lower graft tension was also obtained. The results demonstrated noticeable increases in the meniscal stresses after anterior cruciate ligament reconstruction.

INTERPRETATION

Our results showed that impingement only depends on the femoral tunnel angle. On the contrary, laxity principally depends on the tibial tunnel angle. The angle of the femoral tunnel affects the graft tension while the tibial tunnel affects laxity, meniscal stresses and strains.

Postoperative Imaging of the Knee

The knee is a frequently injured joint and, thus, a common focus of operative intervention. As operative techniques and imaging modalities evolve, radiologists must be aware of the expected postoperative appearance after knee surgeries that are performed commonly and also must be comfortable recognizing complications encountered commonly in the immediate and delayed postoperative period. Drawing on the large amount of attention this subject has received of late in the radiologic and orthopedic literature, this article reviews the knee surgeries performed most commonly and the expected normal and most frequently encountered abnormal postoperative imaging findings with an emphasis on MR imaging.

ACL graft can replicate the normal ligament's tension curve

The anatomical femoral insertion of the normal anterior cruciate ligament (ACL) lies on the deep portion of the lateral wall of the intercondylar fossa. Following the deep bone-cartilage border, it stretches from 11 o'clock high in the notch all the way down to its lowest border at 8 o'clock. The tension curve of the normal ACL during passive flexion-extension shows a characteristic pattern with two tension peaks, one in full extension and the other in deep flexion. Low tension in mid-flexion is measured between those two peaks. Standard ACL reconstructions use a femoral insertion at 11 o'clock, which results in non-physiological tension curves with one peak in full extension only. The hypothesis was that it is possible to reproduce the typical tension curve of the normal ACL by placing the femoral tunnel into the low part of the normal ACL footprint. In a controlled laboratory study, three different femoral tunnel positions at 9, 10 and 11 o'clock were tested in four cadaver knees while using the identical standard tibial tunnel each time. The tension curve was measured during passive flexion-extension with a custom-made tension measurement device, using an artificial Dacron graft. The tension curve of grafts in the 9 o'clock tunnels showed the characteristic pattern of the normal ACL's tension curve with tension peaks in extension as well as in deep flexion. The tunnels in the 10 and 11 o'clock positions failed to reproduce the normal ACL's tension curve with high-tension values in extension only.

CLINICAL RELEVANCE

If an ACL graft is placed low within the normal femoral footprint, the physiological tension curve of the normal ACL can be reproduced.

Revision anterior cruciate ligament reconstruction using a 2-stage technique with bone grafting of the tibial tunnel

BACKGROUND

Revision anterior cruciate ligament surgery is often considered a salvage procedure with limited goals. However, this limitation need not be the case. Similar to primary reconstruction, the goal should be to choose an appropriate graft and place it in an anatomical position in a good quality bone. The issue of good quality bone seems to have been ignored.

HYPOTHESIS

A 2-stage anterior cruciate ligament revision reconstruction with bone grafting of the tibial tunnel and the use of a different femoral tunnel will produce measured knee laxity and International Knee Documentation Committee scores similar to a primary anterior cruciate ligament reconstruction.

STUDY DESIGN

Case control study; Level of evidence, 3.

METHODS

This prospective study involved 49 consecutive 2-stage anterior cruciate ligament revisions (group R) performed by a single surgeon from 1993 to 2000. Two-stage revision surgery was performed if the tibial tunnel from a previous reconstruction surgery would overlap (either partially or fully) the correctly placed revision tunnel. The first stage consisted of removal of the old graft and interfering metalwork, together with bone grafting of the tibial tunnel. After ensuring adequate bone graft incorporation using computed tomography scan, the second stage revision was undertaken. This stage comprised harvesting the autograft, its anatomical placement, and its adequate fixation. The results were compared with the results of a matched group of patients with primary anterior cruciate ligament reconstruction (group P).

RESULTS

In group R, as meniscal and chondral lesions were more common, the International Knee Documentation Committee scores were lower than those of group P (61.2 for group R and 72.8 for group P; P = .006). Objective laxity measurement was similar in both groups (1.36 mm for group R and 1.2 mm for group P; P = .25).

CONCLUSION

This study establishes that the laxity measurements achieved with a 2-stage revision anterior cruciate ligament reconstruction can be similar to those achieved after primary anterior cruciate ligament reconstruction, although the International Knee Documentation Committee rating is lower.

[MRI after meniscus and cruciate ligament surgery]

Nowadays, due to its high diagnostic accuracy, MR imaging is the method of choice for the evaluation of knee joint disorders pre- and postoperatively. Accurate diagnosis is sometimes possible only if the reporting radiologist has knowledge of the therapeutic procedures and the surgical report. Frequently, further therapeutic management is strongly influenced by MR examinations and radiological reports.

MR imaging evaluation of the postoperative knee: ligaments, menisci, and articular cartilage

The surgical management of knee injuries has increased in recent years. Postoperative magnetic resonance (MR) imaging of the knee following surgical intervention serves an important role in the diagnostic evaluation of patients with recurrent or residual symptoms following surgical intervention. MR imaging additionally assists in the noninvasive documentation of temporal changes at the surgical site potentially reflective of procedural success, or failure. Background understanding of the common surgical procedures performed, their normal postoperative MR imaging appearance, and imaging features of potential procedural complications are essential in the accurate evaluation of patients following prior knee surgery. The focus of the following article is to review the clinical and MR imaging features of the postoperative knee following prior surgical treatment of ligamentous, meniscal, and articular cartilage injuries of the joint.

Incidence and risk factors for graft rupture and contralateral rupture after anterior cruciate ligament reconstruction

PURPOSE

The aim of this study was to determine the rates of contralateral anterior cruciate ligament (ACL) rupture and of ACL graft rupture after ACL reconstruction using either patellar tendon or hamstring tendon autograft, and to identify any patient characteristics that may increase this risk.

TYPE OF STUDY

Case series.

METHODS

Over a 2-year period, 760 endoscopic ACL reconstructions were performed in 743 patients. Bone-patellar tendon-bone autograft was used in 316 patients and 4-strand hamstring tendon in 427 patients. Those patients with a previous contralateral ACL rupture or those who underwent a simultaneous bilateral ACL reconstruction were excluded, leaving 675 knees (675 patients) for review. Persons not involved in the index operation or the care of the patient conducted follow-up assessment by telephone interview conducted 5 years after surgery. Patients were questioned about the incidence of ACL graft rupture, contralateral ACL rupture, symptoms of instability or significant injury, family history of ACL injury, and activity level according to the International Knee Documentation Committee scale. From our prospective database we obtained further information on graft source, meniscal or articular surface injury, and gender. Binary logistic regression was used to measure the relative association between the measured variables and the risk of graft rupture and contralateral ACL rupture.

RESULTS

Five years after primary ACL reconstruction, 612 of the 675 patients (90.7%) were assessed. ACL graft rupture occurred in 39 patients (6%) and contralateral ACL rupture occurred in 35 patients (6%). Three patients suffered both a graft rupture and a contralateral ACL injury. The odds of ACL graft rupture were increased 3-fold by a contact mechanism of initial injury. Return to level 1 or 2 sports increased the risk of contralateral ACL injury by a factor of 10. The risk of sustaining an ACL graft rupture was greatest in the first 12 months after reconstruction. No other studied variable increased the risk of repeat ACL injury.

CONCLUSIONS

After reconstruction, repeat ACL injury occurred in 12% of patients over 5 years. Twelve months after reconstruction, the ACL graft is at no greater risk than the contralateral ACL, suggesting that adequate graft and muscular function for most activities is achieved by this time. Risk factors for repeat ACL injury identified included a return to competitive side-stepping, pivoting, or jumping sports, and the contact mechanism of the index injury. Female patients were at no greater risk of repeat ACL injury than male patients and graft choice did not affect the rate of repeat ACL injury.

LEVEL OF EVIDENCE

Level IV, case series.

Imaging evaluation of the postoperative knee ligaments

Until the advent of magnetic resonance imaging (MRI), evaluation of ligament reconstruction of the knee was largely based on clinical examination and radiographs. MRI is the modality of choice for noninvasive evaluation of reconstructed ligaments, menisco-capsular structures and soft tissues. This article reviews the surgical techniques, normal and abnormal appearances of the ACL and PCL grafts and common complications following ligament reconstruction.

The effect of anterior cruciate ligament reconstruction on knee joint kinematics under simulated muscle loads

BACKGROUND

Numerous studies have investigated anterior stability of the knee during the anterior drawer test after anterior cruciate ligament reconstruction. Few studies have evaluated anterior cruciate ligament reconstruction under physiological loads.

PURPOSE

To determine whether anterior cruciate ligament reconstruction reproduced knee motion under simulated muscle loads.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight human cadaveric knees were tested with the anterior cruciate ligament intact, transected, and reconstructed (using a bone-patellar tendon-bone graft) on a robotic testing system. Tibial translation and rotation were measured at 0 degrees, 15 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion under anterior drawer loading (130 N), quadriceps muscle loading (400 N), and combined quadriceps and hamstring muscle loading (400 N and 200 N, respectively). Repeated-measures analysis of variance and the Student-Newman-Keuls test were used to detect statistically significant differences between knee states.

RESULTS

Anterior cruciate ligament reconstruction resulted in a clinically satisfactory anterior tibial translation. The anterior tibial translation of the reconstructed knee was 1.93 mm larger than the intact knee at 30 degrees of flexion under anterior load. Anterior cruciate ligament reconstruction overconstrained tibial rotation, causing significantly less internal tibial rotation in the reconstructed knee at low flexion angles (0 degrees-30 degrees) under muscle loads (P < .05). At 30 degrees of flexion, under muscle loads, the tibia of the reconstructed knee was 1.9 degrees externally rotated compared to the intact knee.

CONCLUSIONS

Anterior cruciate ligament reconstruction may not restore the rotational kinematics of the intact knee under muscle loads, even though anterior tibial translation was restored to a clinically satisfactory level under anterior drawer loads. These data suggest that reproducing anterior stability under anterior tibial loads may not ensure that knee joint kinematics is restored under physiological loading conditions.

CLINICAL RELEVANCE

Decreased internal rotation of the knee after anterior cruciate ligament reconstruction may lead to increased patellofemoral joint contact pressures. Future anterior cruciate ligament reconstruction techniques should aim at restoring 3-dimensional knee kinematics under physiological loads.

Tunnel enlargement and changes in synovial fluid cytokine profile following anterior cruciate ligament reconstruction with patellar tendon and hamstring tendon autografts

There is growing evidence that cytokines such as tumor necrosis factor (TNF) alpha, interleukin (IL) 1beta, IL-6, bone morphogenetic proteins (BMP), and nitric oxide (NO) play an important role in the pathogenesis of bone tunnel enlargement following anterior cruciate ligament (ACL) reconstruction. Furthermore, the release of these mediators has been considered a possible reason for the higher incidence of bone tunnel enlargement following hamstring tendon (HST) than following patellar tendon (PT) ACL reconstruction observed in several studies. In this investigation synovial fluid samples from 13 patients were collected immediately before (24+/-7 days after ACL rupture) and 7 days after ACL surgery and values of TNF-alpha, IL-1beta, IL-6, NO, and BMP-2 were analyzed. Furthermore, the incidence of bone tunnel enlargement was assessed using radiographs 38+/-7 weeks after surgery. Six patients underwent autologous HST ACL reconstruction, and in seven patients an PT autograft was used. In the overall patient population there were significantly higher synovial fluid concentrations of IL-6 and BMP-2 postoperatively than preoperatively; TNF-alpha showed a trend towards lower postoperative levels while IL-1beta and NO remained unchanged. The concentrations of NO, TNF-alpha, and IL-6 found in the present study were clearly higher than normal values given in the literature. Assessment of bone tunnel enlargement revealed an average increase in tibial tunnel width of 28.4+/-3.1% with comparable values for HST and PT ACL reconstructions. There was no significant correlation between bone tunnel enlargement and postoperative synovial fluid concentrations of TNF-alpha, IL-1beta, IL-6, NO, and BMP-2. However, all patients with bone tunnel enlargement had higher postoperative concentrations of TNF-alpha, IL-6, and NO in the synovial fluid. There were no significant differences in concentrations between HST and PT groups. In conclusion, we observed an association between tibial bone tunnel enlargement and elevated synovial fluid concentrations of IL-6, TNF-alpha, and NO 7 days after ACL surgery indicating the potential involvement of these biological mediators in the pathogenesis of bone tunnel enlargement. However, there was no difference between HST and PT ACL reconstructions regarding synovial fluid contents of IL-6, TNF-alpha, IL-1beta, NO, and BMP-2, suggesting a comparable biological response between these autografts following their use in ACL reconstruction.

Current opinion on computer-aided surgical navigation and robotics: role in the treatment of sports-related injuries

Computer-assisted surgery (CAS) may allow surgeons to be more precise and minimally invasive, in addition to being an excellent research tool. Medical imaging, such as magnetic resonance and computed tomography is not only an important diagnostic tool, but also a necessary planning tool. In orthopaedic sports medicine, precision is needed when placing tunnels for soft tissue fixation of replacement grafts. Two types of CAS systems -- passive and active -- have been developed. Passive systems, or surgical navigation systems, provide the surgeon with additional information prior to and during the surgical procedure (in real time). Active systems have the ability of performing certain surgical steps autonomously. Both active and passive CAS systems are currently a subject of basic science and clinical investigations and will be discussed and commented on in this article. In summary, passive navigation systems can provide additional information to the surgeon and can therefore lead to more precise tunnel placement. Active robotic technology seems to be accurate and feasible with promising initial results from Europe. However, active and passive CAS can only be as precise as the surgeon who plans the procedure. Therefore, future studies have to focus on integrating, arthroscopy, 3-D image-enhanced computer navigation, and virtual kinematics, as well as to increase precision in surgical techniques.

Anterior cruciate ligament reconstruction using semitendinosus and gracilis tendons, bone patellar tendon, or quadriceps tendon-graft with press-fit fixation without hardware. A new and innovative procedure

BONE--PATELLAR TENDON: The "no hardware" technique for ACL reconstruction is a new method that offers many advantages and is straightforward to perform. Its main innovative feature is that it does not require bone-block harvesting from the patella. This reduces donor site morbidity and prevents patellar fractures. The bone tunnels are made using tube harvesters and compaction drilling. This minimizes trauma and obviates the risk of bone necrosis. The articular entrance of the tibial tunnel is completely occupied by the grafts. This prevents a windshield-wiper effect and synovial fluid ingress into the tunnel, and enhances graft incorporation. The fact that no hardware is used with both patellar tendon or hamstring grafts significantly reduces the overall cost of the operation and facilitates revision surgery. The quadriceps tendon is also a very good graft. It is thick and has good biomechanical properties and low donor site morbidity. Its disadvantages are: weakness of quadriceps after the operation, an unsightly scar, and some difficulty in graft harvesting [58]. Also, postoperative MRI is not fraught with the problem of metal artifacts. It is difficult to decide which of the methods currently available for ACL reconstruction is the best because most of them give satisfactory results. In the future, assessments of knee ligament reconstruction techniques should look at long-term stability combined with low complication rates. Ease of revision surgery and low cost should also be taken into consideration, given the large annual volume of knee ligament reconstructions (50,000 in the United States alone) [59]. We believe that our technique addresses most of these issues, and that it constitutes a useful alternative method for ACL reconstruction. SEMITENDINOSUS--GRACILIS: This technique, which was used with 915 patients from June 1998 to February 2002, shows a particularly low rate of postoperative morbidity. The reason is probably to be found in the "waterproofing" of the bone tunnels, which lead to less postoperative bleeding and swelling. No drains were used. Rehabilitation follows the same protocol as used for the reconstruction using patellar tendon grafts (accelerated/functional). As expected, there was no widening of the femoral tunnels and little widening of the tibial tunnels. Interestingly, tibial tunnel enlargement was significantly less in a nonaccelarated rehabilitation group than in the accelerated group [60] without affecting stability. The measured internal torque of the hamstrings, as well as their flexion force, already had returned to normal 12 months postoperatively. In a prospective randomized (unpublished) study comparing this technique with ACL reconstruction with BPT grafts with medial or lateral third with only one bone plug (from the tibial tuberosity, see technique described above), we found no significant difference between both groups in subjective scores, stability, KT-1000 values, Tegner activity score, and IKDC at 1-year follow-up. Only the results of kneeling and knee walking testing were significantly better in the hamstring group [61]. In summary, the advantages of this presented technique are: (1) the knot of the graft is close proximally to the anatomic site of the insertion of the ACL, thus avoiding the Bungee effect.; (2) the press-fit tunnel fixation prevents synovial fluid entering the bone tunnels, windshield-wiper effect, and longitudinal motion within the tunnel; the intensive contact between the bony wall of the tunnel and graft collagen over a long distance without any suture material results in quick and complete graft incorporation; and (3) no fixation material means no hardware problems, facilitates revision surgery, and lowers overall costs.

Complications in anterior cruciate ligament surgery

There are many potential problems associated with ACL surgery; however, careful attention to detail can prevent problems from occurring or provide corrective options in the event they do occur. Multiple backup options are not only desirable but also essential to a successful outcome. By following these guidelines, ACL surgery can have good long-term results and return the recreational or higher-level athlete to sports participation.

Revision anterior cruciate ligament reconstruction

Revision ACL surgery is indicated in patients who present with pathologic anterior laxity on clinical examination that reproduces their symptoms of instability during activities of daily living or athletic activities. The goals of the revision ACL surgery are to stabilize the knee, prevent further injury to the articular cartilage and menisci, and maximize the patient's function. Successful revision ACL surgery requires a thorough preoperative evaluation, including a detailed history, physical examination, and radiographic evaluation. Preoperative planning begins with a determination of the mechanisms of failure for the initial ACL reconstruction. Often a primary, as well as secondary cause, for failure can be identified. The determination of the cause of failure is the first step in a carefully-constructed treatment plan, which includes consideration of skin incisions to be used, method of graft removal, hardware removal, the need for a staged procedure or concomitant surgery, graft material selection, tunnel placement, graft fixation, and postoperative rehabilitation protocol. Despite the most meticulous planning, unanticipated findings may be encountered in the operating room, and the preoperative plan should have enough flexibility to accommodate these developments. Finally, it is crucial to counsel the patient preoperatively to limit his or her expectations regarding their surgical outcome. Given the complexity of revision ACL reconstruction, patient expectations must be adjusted to realistically match the potential for success. With proper planning, attention to detail, and appropriate patient expectations, revision ACL surgery can result in a beneficial and satisfying patient outcome.

Accuracy of anterior cruciate ligament tunnel placement with an active robotic system: a cadaveric study

PURPOSE

The objective of this study was to evaluate the accuracy of tunnel placement for ACL reconstruction performed with an active robotic system.

TYPE OF STUDY

Cadaveric analysis.

METHODS

A reference screw containing 4 fiducials was placed in the femur and tibia of 13 fresh-frozen cadaveric knees. A preoperative plan was developed using images from 3-dimensional computed tomography reconstructions of the knee. The active robotic system then drilled the tunnels. The location and direction of each planned tunnel in the femur and tibia were determined from the preoperative plan. To compare these parameters postoperatively, a mechanical digitizer and a tunnel plug were used. The deviation in location and direction between the planned and drilled tunnel was determined.

RESULTS

In preliminary trials, the tibial tunnel was located inaccurately because slippage of the drill bit occurred on the bone at the start of tunnel drilling. This was minimized by decreasing the feed rate of the robot by 75%. For the remaining 10 knees, deviations with respect to the preoperative plan were found of 2.0 +/- 1.2 mm and 1.1 degrees +/- 0.7 degrees for the intra- articular tibial tunnel location and direction, respectively. For the femur, the deviations were 1.3 +/- 0.9 mm for the tunnel location (intra-articular) and 1.0 degrees +/- 0.6 degrees for the tunnel direction.

CONCLUSIONS

The active robotic system is highly accurate for tunnel placement during ACL reconstruction, meaning that the robot drills the tunnels very close to the surgeon's plan. Comparison to a control group of surgeons could not be made because no preoperative plan is usually created in traditional surgery. However, accuracy values in this study were found to be below the values for precision of repeated tunnel placements reported in the literature.

Tensioning of the anterior cruciate ligament graft

A great deal in variability exists in the protocols for graft tensioning. Biologic studies have not been conclusive about the optimum tension for revascularization while minimizing stress relaxation. Clinically, the risk of undertensioning the graft, and thereby not correcting the laxity, must be balanced with the risk of overconstraining the knee, which may lead to pathologic stresses on the joint cartilage, graft failure, or infrapatellar contracture syndrome . Amis and Jakob reported at the European Society of Sports Traumatology Knee Surgery and Arthroscopy scientific workshop in 1998 that most surgeons chose to impose a graft tension of 20 N to 80 N at an average of 11 degrees flexion. Preloading in full or nearly full extension limits the risk of pathologic stresses that can occur at full extension when the graft is tensioned at 30 degrees, but increases the risk of laxity at that angle. For our flexion parameters, we recommend tensioning the graft at 20 degrees to 30 degrees unless the graft tightens or shortens 5 mm or more with knee extension. If shortening occurs, tensioning should be performed in extension. The magnitude of graft tensioning should be tissue specific. For bone-patellar tendon-bone autograft or allograft, 5 pounds of tension should be applied. For hamstring graft, we apply 15 pounds of tension with each bundle tensioned individually.

Biomechanical analysis of an anatomic anterior cruciate ligament reconstruction

BACKGROUND

The focus of most anterior cruciate ligament reconstructions has been on replacing the anteromedial bundle and not the posterolateral bundle.

HYPOTHESIS

Anatomic two-bundle reconstruction restores knee kinematics more closely to normal than does single-bundle reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten cadaveric knees were subjected to external loading conditions: 1) a 134-N anterior tibial load and 2) a combined rotatory load of 5-N x m internal tibial torque and 10-N x m valgus torque. Resulting knee kinematics and in situ force in the anterior cruciate ligament or replacement graft were determined by using a robotic/universal force-moment sensor testing system for 1) intact, 2) anterior cruciate ligament deficient, 3) single-bundle reconstructed, and 4) anatomically reconstructed knees.

RESULTS

Anterior tibial translation for the anatomic reconstruction was significantly closer to that of the intact knee than was the single-bundle reconstruction. The in situ force normalized to the intact anterior cruciate ligament for the anatomic reconstruction was 97% +/- 9%, whereas the single-bundle reconstruction was only 89% +/- 13%. With a combined rotatory load, the normalized in situ force for the single-bundle and anatomic reconstructions at 30 degrees of flexion was 66% +/- 40%and 91% +/- 35%, respectively.

CONCLUSIONS

Anatomic reconstruction may produce a better biomechanical outcome, especially during rotatory loads.

CLINICAL RELEVANCE

Results may lead to the use of a two-bundle technique.

Collapsing the tibial bone tunnel in hamstring autograft reconstruction of the anterior cruciate ligament

The use of double staples is an accepted method for fixation of hamstring anterior cruciate ligament (ACL) grafts at the distal tibial site. In the last year, we have modified the 2-staple technique that we have been using for distal tibial fixation of our double loop hamstring ACL autografts. Previously, we had impacted the graft with 2 toothed staples onto the cortex distal to the opening of the tibial tunnel. The modification we report here involves driving the proximal staple into the tibial tunnel roof, thus collapsing the tunnel onto the tendon during fixation. The distal staple is introduced in the usual manner. Clinical follow-up including subjective and objective KT-1000 arthrometry has indicated no difference in the early results compared with the former staple technique. Radiologic follow-up showed tunnel obliteration and filling in the area of the proximal staple, suggesting early graft incorporation in callus. While early results are encouraging, long-term follow-up and pullout studies will be reported. It would appear that collapsing the bony tunnel by the proximal staple may be a simple method of providing fracture callus to increase the stiffness of the tibial graft fixation, with no major or minor complications. Animal experiments are being carried out to objectively define the mechanical advantage of the graft incorporation by callus.

Patient satisfaction needs as related to knee stability and objective findings after ACL reconstruction using the LARS artificial ligament

The purposes of this study are to compare patient satisfaction with the objective measurement of knee stability and assess early complications following ACL reconstruction using a LARS artificial ligament. Forty-seven patients were reviewed 8-45 months after surgery. Assessment was made by the Knee and Osteoarthritis Outcome Score for patient satisfaction, a modified International Knee Documentation Committee form for clinical knee stability, and a Telos stress radiography for PA stability. Complications were assessed at interview and were double-checked with charts. The LARS artificial ligament may be a safe device to reconstruct an ACL tear. Documenting mechanical stability of the knee is inadequate when reporting follow-up studies and a questionnaire assessing patient satisfaction should be added to provide a better picture of the outcome and results.

Mechanical behavior of two hamstring graft constructs for reconstruction of the anterior cruciate ligament

We compared the mechanical behavior of two common hamstring graft constructs that are frequently used for reconstruction of the anterior cruciate ligament-Graft A: quadrupled semitendinosus tendon fixed with titanium button/polyester tape and suture/screw post, and Graft B: a double semitendinosus and double gracilis tendon fixed with a cross pin and two screws over washers. The experimental protocol used to evaluate each graft construct included stress relaxation (with and without preconditioning), cyclic loading, and a tensile load-to-failure test. The amount of stress relaxation without preconditioning was 60.6% for Graft A and 53.8% for Graft B. With preconditioning, it significantly decreased (p < 0.05) to 48.7 and 42.3%, respectively. Elongation of the graft construct in response to 100 cycles of loading (20-150 N) was 1.8 and 0.6% of the original length for Grafts A and B, respectively. However, after a series of five cyclic loading tests, the residual permanent elongation for each construct was 3.8 +/- 1.2 and 0.3 +/- 0.2 mm, a significant difference (p < 0.05) between the two graft constructs. Further analysis found more than 90% of the permanent elongation in the proximal and distal regions of Graft A, which consisted of polyester tape tied to a titanium button (proximal) and sutures tied around a screw post (distal). The tensile load-to-failure tests also revealed significant differences (p < 0.05) between the two graft constructs. Linear stiffness was 32 +/- 1 and 119 +/- 19 Nmm and ultimate load was 415 +/- 36 and 658 +/- 128 N for Grafts A and B, respectively. For Graft A, the polyester tape consistently failed; for Graft B, slippage or tearing from the washers was the mode of failure. We conclude that a quadruple-hamstring graft fixed over a cross pin proximally and with metal washers distally (Graft B) has less permanent elongation in response to cyclic loading and has structural properties superior to those of a graft construct that includes suture and tape material (Graft A). The large permanent elongation following repetitive loading of a graft construct with tape and suture material during the early postoperative period is of concern.

The natural history of the intercondylar notch after notchplasty

Ten patients who underwent anterior cruciate ligament reconstruction by one surgeon using autologous patellar tendon grafts were evaluated. A standardized technique of performing a notchplasty was done to remove at least 5 mm of bone at the anterior outlet of the intercondylar notch. Computed tomography scans were done preoperatively, within 1 week postoperatively, and after 1 year of follow-up. There were no statistically significant differences in the measured dimensions of the intercondylar notch between 1 week and 1 year postoperatively. While previous investigations have evaluated the relationship between intercondylar notch dimensions and risk of anterior cruciate ligament injury, we believe this is the first statistical study that addresses the natural history of the intercondylar notch in humans after bone resection. We believe that the data reported here may enhance our understanding and treatment of patients who have undergone previously failed anterior cruciate ligament reconstructions.

Revision anterior cruciate ligament surgery

An increasing number of revision ACL reconstructions are being performed each year. Revision ACL surgery is challenging and cannot be approached in the same manner as primary ACL surgery. Successful revision ACL surgery requires a detailed history, a comprehensive physical examination, appropriate radiologic studies, and careful preoperative planning. The results of revision ACL surgery do not equal the results of primary ACL surgery, and this should be explained to the patient prior to surgery. In order to avoid repeating errors that led to failure of the primary reconstruction, the etiology of the primary failure must be clearly understood before proceeding with the revision procedure. Although graft failure is the most common reason for failure of the original reconstruction and revision surgery, other non-graft-related problems, such as loss of motion, extensor mechanism dysfunction, and degenerative arthritis, can also result in an unsatisfactory outcome and residual complaints. Errors in surgical technique, specifically nonanatomic graft placement and failure to address associated ligamentous injuries at the time of the original procedure, are responsible for graft failures in most reported series. Preoperative planning must address the issues of graft selection, skin incisions, hardware removal, tunnel placement, graft fixation, and associated ligamentous injuries. Loss of motion and in some cases enlarged bone tunnels may require a staged approach. Because of the weaker initial graft fixation, laxity of secondary restraints, the potential need to address associated ligamentous injuries, and the presence of more significant articular cartilage changes, an accelerated rehabilitation program is inappropriate in most revision cases. Successful revision ACL surgery requires a motivated and compliant patient, a well thought out plan, and an experienced surgeon who is knowledgeable and proficient with a variety of different surgical techniques, graft sources, and graft fixation techniques.

Ipsi- or contralateral patellar tendon graft in anterior cruciate ligament revision surgery. A comparison of two methods

Twenty-four patients who underwent anterior cruciate ligament revision surgery were studied postoperatively (12 with reharvested ipsilateral patellar tendon grafts and 12 with contralateral patellar tendon grafts). For comparison purposes, 12 matched patients with primary anterior cruciate ligament reconstruction, who had been operated on using the same technique by the same surgeons, were chosen. The median time since the first reconstruction was 57 months (range, 15 to 132) in the ipsilateral tendon group and 54 months (range, 20 to 108) in the contralateral tendon group. Follow-up examination showed that there were no significant differences in total KT-1000 arthrometer side-to-side measurements between the groups, but the Lysholm score was higher for patients with contralateral tendon grafts than for patients with ipsilateral grafts. Only two patients with ipsilateral grafts were classified as having excellent or good results. Functional testing outcomes were similar for all groups, and magnetic resonance imaging screening showed no differences between the reharvest and primary harvest groups in terms of length, width, thickness, or donor site gap of the patellar tendon. However, there were two major complications in the group with revision surgery with the ipsilateral reharvested patellar tendon. Reharvesting the ipsilateral patellar tendon resulted in lower functional scores and a higher rate of complications than revision with the contralateral patellar tendon or primary anterior cruciate ligament reconstruction.

The Human Genome Project: implications for the treatment of musculoskeletal disease

The ultimate goal of the Human Genome Project is the determination of the molecular sequence of the entire human chromosomal complement. Realization of this goal will include characterization of all the genes that cause or predispose to disease, which will most certainly lead to the development of powerful new tools for diagnosis, prevention, and treatment in all medical fields, including orthopaedics. The authors review the fundamentals of human genetics and gene mapping, summarize the progress of the Human Genome Project thus far, and discuss the implications of this research as it relates to the treatment of musculoskeletal diseases.

Revision anterior cruciate ligament surgery: experience from Miami

Failed anterior cruciate ligament reconstruction as defined by recurrent patholaxity is increasingly commonplace. This report presents the findings of 54 patients who had unsuccessful intraarticular anterior cruciate ligament reconstruction to correct persistent instability and who subsequently underwent revision anterior cruciate ligament surgery. Before revision, patients were evaluated by clinical examination, KT-1000 arthrometer, radiographs, Lysholm knee score, Tegner activity scale, and subjective questionnaire. The results were compared at a mean of 32 months following revision surgery. There was an average of 16 months from index procedure to the time of revision. Autogenous patellar tendon grafts were used in 61% of the cases with 30% of these harvested from the contralateral knee. Fresh frozen patellar tendon was used in 35% and autogenous hamstring tendons in 4%. Revision was successful in objectively improving stability in all patients with an average KT-000 of 2.8 mm. Autogenous tissue grafts provided greater objective stability when compared with allograft tissue with average KT-1000 of 2.2 and 3.3, respectively. Functionally, however, there was no significant difference in outcome between the 2 groups. Harvesting of the contralateral patellar tendon was found to have no adverse long term effect. Subjectively, the results were significantly worse depending on the degree of articular cartilage degeneration. Only 54% of patients returned to their preanterior cruciate ligament injury activity level. Competence in various anterior cruciate ligament reconstruction techniques will facilitate revision surgery especially in avoiding preexisting tunnels and hardware. Correct graft placement and addressing the secondary restraints are critical to successful revision surgery.