Ligament stability two to six years after anterior cruciate ligament reconstruction with autogenous patellar tendon graft and participation in accelerated rehabilitation program

Bone-patellar tendon-bone, hamstring, and quadriceps tendon autografts for anterior cruciate ligament reconstruction in skeletally immature patients: a systematic review

INTRODUCTION

Historically, anterior cruciate ligament (ACL) ruptures in the paediatric age group were managed conservatively with bracing, casting, activity modification, and physical therapy. However, most of these patients had to reduce their sports activities, and secondary damages to the affected knee were prevalent.

SOURCE OF DATA

Published scientific literature in Embase, Web of Science, PubMed, and Google Scholar databases.

AREAS OF AGREEMENT

ACL reconstruction in children with open physes patients is debated. Any damage to the physes around the knee could lead to growth abnormalities and axial deviation of the knee.

AREAS OF CONTROVERSY

Different grafts are available and suitable for ACL reconstruction in skeletally immature patients; however, which graft performs better remains unclear.

GROWING POINTS

This systematic review compared bone-patellar tendon-bone (BPTB), hamstring tendon (HT), and quadriceps tendon (QT) autografts for ACL reconstruction in skeletally immature patients. The joint laxity, Patient-reported outcome measures (PROMs), return to sport, and complications were compared.

AREAS TIMELY FOR DEVELOPING RESEARCH

In skeletally immature patients, HT, BPTB, and QT autografts for ACL reconstruction yielded good outcomes. Comparative studies are strongly required to establish the most suitable autograft.

Platelet-Rich Fibrin-Augmented Gap-Bridging Strategy in Rabbit Anterior Cruciate Ligament Repair

BACKGROUND

We assessed the efficacy of a novel platelet-rich fibrin (PRF)-augmented repair strategy for promoting biological healing of an anterior cruciate ligament (ACL) midsubstance tear in a rabbit model. The biological gap-bridging effect of a PRF scaffold alone or in combination with rabbit ligamentocytes on primary ACL healing was evaluated both in vitro and in vivo.

HYPOTHESIS

A PRF matrix can be implanted as a provisional fibrin-platelet bridging scaffold at an ACL defect to facilitate functional healing.

STUDY DESIGN

Controlled laboratory study.

METHODS

The biological effects of PRF on primary rabbit ligamentocyte proliferation, tenogenic differentiation, migration, and tendon-specific matrix production were investigated for treatment of cells with PRF-conditioned medium (PRFM). Three-dimensional (3D) lyophilized PRF (LPRF)-cell composite was fabricated by culturing ligamentocytes on an LPRF patch for 14 days. Cell-scaffold interactions were investigated under a scanning electron microscope and through histological analysis. An ACL midsubstance tear model was established in 3 rabbit groups: a ruptured ACL was treated with isolated suture repair in group A, whereas the primary repair was augmented with LPRF and LPRF-cell composite to bridge the gap between ruptured ends of ligaments in groups B and C, respectively. Outcomes-gross appearance, magnetic resonance imaging, and histological analysis-were evaluated in postoperative weeks 8 and 12.

RESULTS

PRFM promoted cultured ligamentocyte proliferation, migration, and expression of tenogenic genes (type I and III collagen and tenascin). PRF was noted to upregulate cell tenogenic differentiation in terms of matrix production. In the 3D culture, viable cells formed layers at high density on the LPRF scaffold surface, with notable cell ingrowth and abundant collagenous matrix depositions. Moreover, ACL repair tissue and less articular cartilage damage were observed in knee joints in groups B and C, implying the existence of a chondroprotective phenomenon associated with PRF-augmented treatment.

CONCLUSION

Our PRF-augmented strategy can facilitate the formation of stable repair tissue and thus provide gap-bridging in ACL repair.

CLINICAL RELEVANCE

From the translational viewpoint, effective primary repair of the ACL may enable considerable advancement in therapeutic strategy for ACL injuries, particularly allowing for proprioception retention and thus improved physiological joint kinematics.

Range of Motion, Strength, and Function After ACL Reconstruction Using a Contralateral Patellar Tendon Graft

BACKGROUND

Regaining preinjury levels of activity and progressing rehabilitation factors after anterior cruciate ligament (ACL) reconstruction have shown mixed results.

PURPOSE

To evaluate the timing and rate of return for knee range of motion (ROM), stability, strength, and subjective scores after ACL reconstruction with contralateral patellar tendon graft (PTG).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Included were 2148 patients (1238 male patients, 910 female patients) who underwent primary ACL reconstruction with a contralateral PTG between 1995 and 2017 and had complete objective data through 3 months of follow-up. All patients participated in a rehabilitation program specific to goals for each knee. Patients were evaluated objectively with goniometric measurement of ROM, isokinetic quadriceps strength testing, and laxity with a KT-2000 arthrometer. Subjective data were collected at 2 and 5 years.

RESULTS

Normal extension on the reconstructed knee was attained for 95% of patients at 1 week postoperatively; normal flexion on the reconstructed knee was reached by 77% of patients by 3 months. At 3 months postoperatively, mean limb symmetry index strength was 104%, and the strength on the ACL-reconstructed and graft-donor knees was 87% and 86% of their respective preoperative strength. Mean manual maximum side-to-side difference in laxity was 2.0 mm at 1 month. Most patients (90%) returned to level 8 sports or higher and did so at an average of 5.7 months. Mean International Knee Documentation Committee scores for the ACL-reconstructed and graft-donor knees were 89 and 91 at 2 years (n = 1015 patients) and 84 and 90 at 5 years (n = 1275 patients), respectively. Mean Cincinnati Knee Rating Scale scores for the ACL-reconstructed and graft-donor knees were 92 and 96 at 2 years (n = 1184) and 88 and 94 at 5 years (n = 1236), respectively.

CONCLUSION

For patients who underwent ACL reconstruction with a contralateral PTG, postoperative ROM and strength were restored quickly by splitting the rehabilitation into different goals between the two knees. Using a contralateral PTG, this structured rehabilitation plan can lead to a relatively quick return to sport and good subjective long-term outcomes.

Accelerated Versus Non-accelerated Rehabilitation After Primary Anterior Cruciate Ligament Reconstruction Using Hamstring Autografts: A Systematic Review and Meta-analysis of Comparative Studies

PURPOSE

This study aimed to compare the clinical outcomes between accelerated rehabilitation (AR) and non-accelerated rehabilitation (NR) after anterior cruciate ligament reconstruction (ACLR) using hamstring autografts through a systematic review and meta-analysis.

METHODS

To compare the outcomes between AR and NR, we searched Medline, Embase, and the Cochrane Library. Studies comparing their clinical outcomes after ACLR using hamstring autografts were included. AR was characterized by the starting range of motion and weight-bearing within 3 days and return to sports within 6-9 months. A meta-analysis of clinical outcome parameters used in ≥ 3 studies was conducted.

RESULTS

Seven studies were included. The International Knee Documentation Committee subjective score was significantly higher in AR than in NR at the 3- (mean difference [MD], 7.30; 95% confidence interval [CI] 1.55-13.05; P = 0.013) and 6-month follow-ups (MD, 5.64; 95% CI 0.11-11.17; P = 0.046). The side-to-side difference in anterior tibial translation at the final follow-up assessed in four studies was significantly lower in NR than in AR (MD, 0.59; 95% CI 0.12-1.07; P = 0.015). Overall Tunnel widening at the final follow-up assessed in four studies was also smaller in NR than in AR (MD, 0.48; 95% CI 0.00-0.96; P = 0.0479). However, the mean side-to-side difference and overall tunnel widening between them was < 1 mm.

CONCLUSION

The early subjective clinical outcomes of AR after ACLR using hamstring autografts were superior to those of NR. Although tunnel widening and anterior instability were also significantly larger in AR than in NR, the difference was not clinically relevant.

Biological Augmentation of ACL Repair and Reconstruction: Current Status and Future Perspective

Historically, anterior cruciate ligament (ACL) suture repair mostly resulted in failure because of intra-articular hypovascularity and poor intrinsic healing capacity of ACL. ACL reconstruction was therefore deemed the gold standard with a high success rate because of more evolved surgical technique. There are, however, clinical and subclinical disadvantages of reconstruction; low rate in full recovery to sports, donor harvest morbidity, tunnel enlargement, and incomplete microscopic healing of the graft. Recent experimental and clinical studies on biological augmentation of mesenchymal stem cells, platelet-rich plasma, or the other biologic agents with scaffold suggested potential feasibility of positive effects by such bio-therapies for both ACL repair and reconstruction. Biological augmentation of ACL surgery is still in the exploratory stages and more evidence from preclinical and clinical studies is required for implementation in clinical practice.

Increased knee laxity with hamstring tendon autograft compared to patellar tendon autograft: a cohort study of 5462 patients with primary anterior cruciate ligament reconstruction

PURPOSE

To compare anterior knee laxity and patient-reported outcome measures (PROMs) between anterior cruciate ligament reconstruction (ACLR) performed with bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts and, moreover, to study any correlation between postoperative anterior knee laxity and PROMs.

METHODS

Patients who underwent primary ACLR at Capio Artro Clinic, Stockholm, Sweden, from January 2000 to October 2015, were identified in our local database. Instrumented laxity measurements and PROMs were reviewed. The KT-1000 arthrometer, with an anterior tibial load of 134-N, was used to evaluate knee laxity preoperatively and at the 6-month follow-up. The Lysholm score was collected preoperatively and at 6 months postoperatively. The Knee injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and at the 1-year follow-up.

RESULTS

A total of 5462 primary ACLRs, 692 BPTBs and 4770 HT autografts were included in the study. All the patients showed a significant reduction in knee laxity from preoperatively to postoperatively (BPTB group: from 3.8 ± 2.6 to 1.2 ± 2.1 mm; HT group: from 3.6 ± 3.1 to 1.8 ± 2.2 mm; P < 0.001 for both). The HT group showed a significantly increased postoperative knee laxity compared with the BPTB group (1.8 ± 2.2 vs 1.2 ± 2.1 mm; P < 0.001). The mean anterior tibial translation (ATT) reduction from preoperative to postoperative was significantly larger for the BPTB graft compared with the HT graft (2.7 ± 2.2 vs 1.7 ± 2.6 mm; P < 0.001). A significantly higher rate of "surgical failures", defined as a postoperative side-to-side (STS) difference > 5 mm, was found in the HT group compared with the BPTB group at follow-up (4.3 vs 2.4%; P < 0.001). A significantly larger improvement was found in the HT group compared with the BPTB group for the KOOS Pain (9.5 vs 8.0; P = 0.02), Activities of Daily Living (7.2 vs 5.7; P = 0.006), Sports (24.2 vs 15.3; P < 0.001) and Quality of Life (25.8 vs 22.1; P = 0.001) subscales. No significant difference regarding the mean improvement in the Lysholm knee score was found between the two grafts (BPTB group: 14.5, HT group: 14.0; n.s.). No correlation between postoperative anterior knee laxity and PROMs was found in either graft group.

CONCLUSION

Primary ACLR performed with HT autograft resulted in greater postoperative anterior knee laxity and significantly more surgical failures (STS > 5 mm) compared with BPTB autograft. The BPTB autograft showed a larger anterior knee laxity reduction (ATT reduction) in conjunction with primary ACLR. The HT autograft led to a significantly larger improvement in four of five KOOS subscales from preoperatively to the 1-year follow-up, compared with BPTB autograft. There was no association between postoperative anterior knee laxity and PROMs for either graft. The findings of the present study provide clinicians with valuable information regarding differences in knee laxity and subjective knee function between BPTB and HT autograft after primary ACLR. The use of BPTB autograft should be considered for patients with high knee stability demands.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

The Effects of Bone Marrow-Derived Mesenchymal Stem Cells and Fascia Wrap Application to Anterior Cruciate Ligament Tissue Engineering

After an anterior cruciate ligament (ACL) injury, surgical reconstructions are necessary in most cases, either with autografts, allografts, or artificial ligaments. Potential tissue-engineered ligaments would circumvent the disadvantages apparent in these methods. While seeding of mesenchymal stem cells (MSCs) and fascia wrap could potentially improve tissue regeneration and mechanical properties, their exact roles were evaluated in the current study. Knitted biodegradable scaffolds of poly-L-lactic acid (PLLA) and poly-glycolic-lactic acid (PGLA) yarns were used to reconstruct ACL in 48 rabbits. These were divided into four equal groups: only knitted scaffolds were used in group I; knitted scaffolds and mesenchymal stem cells were used in group II; knitted scaffolds, MSCs, and fascia lata were used in group III; knitted scaffolds and fascia lata were used in group IV. Carboxyfluorescein diacetate (CFDA)-labeled MSCs were used to trace the fate of seeded cells in groups II and III. Histology, Western blot analysis, and mechanical properties of reconstructed ACL were analyzed after 20 weeks. Fibroblast ingrowths were seen in all four groups while CFDA-labeled MSCs could be found after 8 weeks of implantation in groups II and III. Both the amount of collagen type I and collagen type III in groups III and IV were significantly higher than in group II, which was much higher than in group I. Both maximal tensile loads and stiffness of the reconstructed ACLs in groups I, II, III, and IV were significantly lower than normal controls after 20 weeks of implantation. It is concluded that MSCs could promote synthesis of collagen type I and collagen type III in tissue-engineered ligaments, while fascia wraps have stronger effects. Both MSC seeding and fascia wrap could not enhance ultimate tensile load and stiffness.

Technical variables of ACL surgical reconstruction: effect on post-operative static laxity and clinical implication

PURPOSE

The hypothesis was that an alteration of different surgical variables of ACL reconstruction would produce significant changes in post-operative static laxity of knee joint.

METHODS

Joint laxity was acquired by a surgical navigation system for 17 patients just after graft fixation during single-bundle reconstruction with extra-articular lateral tenodesis. The analysed laxity parameters were: internal/external rotation at 30° (IE30) and 90° (IE90) of flexion, varus/valgus rotation at 0° (VV0) and 30° (VV30) of flexion and anterior/posterior displacement at 30° (AP30) and 90° (AP90) of flexion. As surgical variables, the angles between the tibial tunnel and the three planes were defined as well as the lengths of the tunnel and the relationship between native footprints and tunnels. The same analysis was performed for the femoral side. All surgical variables were combined in a multivariate analysis to assess for predictive factors between them and post-operative laxities values. To quantify the performance of each multivariate model, the correlation ratio (η ²) and the corresponding P value (*P < 0.050) have been evaluated.

RESULTS

Multivariate analysis underlined statistically significant models for the estimation of: AP30 (η ² = 0.987; P = 0.014), IE30 (η ² = 0.995; P = 0.005), IE90 (η ² = 0.568; P = 0.010), VV0 (η ² = 0.932; P = 0.003). The parameters that greatly affected the identified models were the orientation of the tibial tunnel with respect to the three anatomical planes. The estimation of AP30, IE30 and IE90 got lower value as the orientation of the tibial tunnel with respect to transverse plane decreases. Considering the orientation to sagittal ([Formula: see text]) and coronal ([Formula: see text]) plane, we found that their reduction provoked a decrease in the estimation of AP30, IE30 and IE90 (except [Formula: see text] that did not appear in the estimation of AP30). The estimation of VV0 got an increase of [Formula: see text], and [Formula: see text] which led to a laxity reduction.

CONCLUSION

The main finding of the present in vivo study was the possibility to determine significant effects on post-operative static laxity level of different surgical variables of ACL reconstruction. In particular, the present study defined the conditions that minimize the different aspects of post-operative laxity at time-zero after surgery.

Patient-based decision for resuming activity after ACL reconstruction: a single-centre experience

PURPOSE

The purpose of the study was to report the functional outcome following anterior cruciate ligament (ACL) reconstruction in patients who decide when to resume work and normal sporting activity post-operatively. The hypothesis tested was that patient-based decision to return to work and sport was possible without compromising functional outcome and increased the rate of repeat rupture in comparison with the existing literature.

METHODS

This was a monocentric, retrospective study. Seventy-two patients requiring primary ACL reconstruction were included. All patients were followed up for a mean period of 4.3 years. Return to work and to sporting activity was allowed based on patient's decision. No restriction was suggested by the physician. Delays to return to work and sports and occurrence of graft failure were documented.

RESULTS

Sixty-six patients (92 %) returned to any sporting activity. The mean delay was 4.1 months for running, 6.1 months for pivoting sports, and 6.6 months for contact sports. Return to competitive sport was possible in 82 % of patients after a mean delay of 7.1 months. Return to work was possible for 96 % of patients after a mean delay of 2.3 months. Index Tegner score normalized in 71 % of patients. Four repeat ruptures (6 %) were observed, all of them following a significant knee injury.

CONCLUSIONS

Patient-based decision to return to work and sport was possible without compromising functional outcome. The post-operative restrictions implemented by orthopaedic surgeons following ACL reconstructions may be relaxed and more patient based.

Biomechanical comparison of rotational activities between anterior cruciate ligament- and posterior cruciate ligament-reconstructed patients

PURPOSE

The purpose of this study was to compare the early functional recovery using biomechanical properties between anterior cruciate ligament (ACL)- and posterior cruciate ligament (PCL)-reconstructed patients and to determine the biomechanical deficit of PCL-reconstructed patients compared to ACL-reconstructed patients.

METHODS

A motion analysis system was used to measure and calculate kinematic and kinetic data for 10 patients who underwent PCL-reconstructed patients [experimental group (group 1)], 10 ACL-reconstructed patients (group 2), and 10 healthy subjects (group 3) during 45°, 90°, 135°, and 180° cutting and turn running tasks. Groups 1 and 2 were assessed at 3 (return to daily activity) and 6 months (return to light sports) postoperatively.

RESULTS

At 3 months postoperatively, compared to groups 2 and 3, group 1 showed a decrease in knee flexion angle, extension moment, valgus moment, external rotational moment, ground reaction force, and increased hamstring-quadriceps ratio. At 6 months postoperatively, results from group 1 resembled those of groups 2 and 3 over time.

CONCLUSIONS

Patients who underwent PCL reconstruction showed some biomechanical deficits in performance of activities requiring rotation, compared to those who underwent ACL reconstruction. Therefore, the modification of a rehabilitation programme for patients who underwent PCL reconstruction would be necessary for improvement of the biomechanical properties during performance of dynamic activities.

LEVEL OF EVIDENCE

Case-control study, Level III.

Variability of tunnel positioning in ACL reconstruction

INTRODUCTION

Since tunnel positioning is one of the key factors in anterior cruciate ligament (ACL) reconstruction and the variability of tunnel positioning in ACL reconstruction has so far never been analyzed, the objective of this study was to determine the inter- and intra-observer variability of tibial and femoral tunnel positioning in ACL reconstruction.

MATERIALS AND METHODS

In an operating room setup, 13 surgeons were asked to identify the tunnel positions in one and the same ACL-deficient cadaver knee. Using a fluoroscopic based ACL navigation system, tunnel positions were digitally measured in a test/re-test scenario. For variability analysis mean positions, standard deviations and range were calculated as well as differences between test/re-test positions.

RESULTS

The intraobserver analysis showed a tibial variability of 3.3 mm (SD 2.1, range 7.5 mm) and a femoral variability of 2.0 mm (SD 1.6 mm, range 6.8 mm). The interobserver variability of the tibial tunnel positions was 3.2 mm (SD) with a range of 18.3 mm and a femoral variability of 3.7 mm (SD) with a range of 13.2 mm.

CONCLUSIONS

This study demonstrates that a reasonable inter- and intra-observer variability in ACL tunnel positioning exists even among experienced surgeons. Although deviations of 2-3 mm may seem to be acceptable at first sight, a range of up to 18.3 mm indicates that outliers exist, which can cause graft failure. More reliable reconstruction techniques should be developed to reduce the variability in tunnel positioning.

Effect of a too posterior placement of the tibial tunnel on the outcome 10-12 years after anterior cruciate ligament reconstruction using the 70-degree tibial guide

PURPOSE

To examine the relationship between the radiographically assessed placement of the tibial tunnel and the long-term clinical and subjective outcome in anterior cruciate ligament-reconstructed patients.

METHODS

Patients were examined clinically, with subjective score systems and with standardised radiographs 10-12 years postoperatively. Only patients reconstructed with the aid of the 70-degree tibial drill guide were included. A posterior placement of the tibial tunnel was defined as >50% along the Amis and Jakob line (AJL). A high tunnel inclination was defined as >75° in the coronal plane. The possible linear relationships between clinical findings, subjective scores and tibial tunnel placement were investigated.

RESULTS

Eighty-six percentage of the 96 patients were available for examination. Mean tibial tunnel inclination was 71.1° (SD 4.2). No difference was found in subjective scores and knee stability between high (14%) and low (86%) inclination groups. Mean placement of the tibial tunnel along the AJL was 46% (SD 5). Patients with a posterior tibial tunnel placement (24%) had a higher incidence of rotational instability (P = 0.02). Patients with rotational instability (grade 2 pivot shift) had significant lower Lysholm score than those with grade 0 and 1 rotational instability (P = 0.001).

CONCLUSIONS

The use of a tibial drill guide that relates to the femoral roof leads to a posterior tibial tunnel placement (>50% of the tibial AP-diameter) in 24% of the patients. These patients have a significant higher proportion of rotational instability and worse subjective outcome.

LEVEL OF EVIDENCE

Case series, Level IV.

The in vivo relationship between anterior neutral tibial position and loss of knee extension after transtibial ACL reconstruction

BACKGROUND

Restoration of anterior tibial stability while avoiding knee extension deficit are a common goal of anterior cruciate ligament (ACL) reconstruction. However, achieving this goal can be challenging. The purpose of this study was to determine whether side-to-side differences in anterior tibial neutral position and laxity are correlated with knee extension deficit in subjects 2 years after ACL reconstruction.

METHODS

In the reconstructed and contralateral knees of 29 subjects with transtibial reconstruction, anterior tibiofemoral neutral position was measured with MRI and three-dimensional modeling techniques; terminal knee extension at heel strike of walking and during a seated knee extension were measured via gait analysis; and anterior laxity was measured using the KT-1000.

RESULTS

Knees that approached normal anterior stability and anterior tibial position had increased extension deficit relative to the contralateral knee. On average the reconstructed knee had significantly less (2.1±4.4°) extension during active extension and during heel strike of walking (3.0±4.3º), with increased anterior neutral tibial position (2.5±1.7 mm) and anterior laxity (1.8±1.0 mm). There was a significant correlation between side-to-side difference in anterior neutral tibial position with both measures of knee extension (walking, r=-0.711, p<0.001); active knee extension, r=-0.544, p=0.002).

CONCLUSION

The results indicate a relationship between the loss of active knee extension and a change in anterior neutral tibial position following non-anatomic transtibial ACL reconstruction. Given the increasing evidence of a link between altered kinematics and premature osteoarthritis, these findings provide important information to improve our understanding of in vivo knee function after ACL reconstruction.

Rehabilitation after posterior cruciate ligament reconstruction: a review of the literature and theoretical support

INTRODUCTION

The purpose of this study was to conduct a literature review of studies that have addressed rehabilitation after posterior cruciate ligament (PCL) reconstruction. In particular, we intended to perform categorical analysis and discuss some critical points.

MATERIALS AND METHODS

A literature review of English language articles was performed using the PubMed databases. Our literature search was performed using the following text words: [posterior cruciate ligament OR PCL] AND [reconstruction] AND [rehabilitation]. A total of 34 articles met our criteria and were included in the final systematic review. Rehabilitation protocols were reviewed and tabulated according to main rehabilitation protocol categories [range of motion (ROM), weight bearing, bracing, and strengthening].

RESULTS

Ranges of motion of 90° and 120° were allowed at 4-8 and 6-12 weeks postoperatively in 70 % of studies. Full weight bearing was delayed until 6 weeks postoperatively in 60 % of studies. Most studies (73 % of studies) used a brace for 6-8 weeks and active hamstring exercise was not allowed for 6-24 weeks postoperatively.

CONCLUSIONS

The review showed that flexion of 90° was allowed at around 6 weeks and prone passive flexion exercise or supine passive ROM exercise with posterior support was used to prevent a posteriorly directed force. Most authors used non-weight bearing or partial weight bearing in their rehabilitation programs, however it may be possible to perform active weight bearing in full extension or early flexion grades as soon as the soft tissue situation allows. Co-strengthening exercises could be recommended because these exercises produce co-contraction between the quadriceps and hamstring muscles with little posterior shear force.

Biomechanical evaluation of augmented and nonaugmented primary repair of the anterior cruciate ligament: an in vivo animal study

PURPOSE

The purpose of this study was to evaluate in a sheep model the biomechanical performance of augmented and nonaugmented primary repair of the anterior cruciate ligament (ACL) following transection at the femoral end during a 12-month postoperative observation.

METHODS

Forty sheep were randomly assigned to nonaugmented or augmented primary ACL repair using a polyethylene terephthalate (PET) band. At two, six, 16, 26 and 52 weeks postoperatively four sheep in each group were sacrificed and biomechanical testing performed.

RESULTS

Compared with nonaugmented primary ACL repair, the PET-augmented repair demonstrated superior biomechanical results from 16 weeks postoperatively onwards in terms of anterioposterior (AP) laxity, tensile strength and ligament stiffness. The augmentation device works as a stress shield during the ligament healing process. The nonaugmented ACL repair also resulted in ligament healing, but the biomechanical properties were at a significantly lower level.

CONCLUSION

These results support the previously reported histological findings following augmented primary ACL repair. This animal study on the healing capacity of the ACL may provide some important contributions to how primary healing in certain types of ruptures can be achieved.

CLINICAL RELEVANCE

I.

Cruciate ligament loading during common knee rehabilitation exercises

Cruciate ligament injuries are common and may lead to dysfunction if not rehabilitated. Understanding how to progress anterior cruciate ligament and posterior cruciate ligament loading, early after injury or reconstruction, helps clinicians prescribe rehabilitation exercises in a safe manner to enhance recovery. Commonly prescribed therapeutic exercises include both weight-bearing exercise and non-weight-bearing exercise. This review was written to summarize and provide an update on the available literature on cruciate ligament loading during commonly used therapeutic exercises. In general, weight-bearing exercise produces smaller loads on the anterior cruciate ligament and posterior cruciate ligament compared with non-weight-bearing exercise. The anterior cruciate ligament is loaded less at higher knee angles (i.e. 50-100 degrees). Squatting and lunging with a more forward trunk tilt and moving the resistance pad proximally on the leg during the seated knee extension unloads the anterior cruciate ligament. The posterior cruciate ligament is less loaded at lower knee angles (i.e. 0-50 degrees), and may be progressed from level ground walking to a one-leg squat, lunges, wall squat, leg press, and the two-leg squat (from smallest to greatest). Exercise type and technique variation affect cruciate ligament loading, such that the clinician may prescribe therapeutic exercises to progress ligament loading safely, while ensuring optimal recovery of the musculoskeletal system.

Recent advances following anterior cruciate ligament reconstruction: rehabilitation perspectives : Critical reviews in rehabilitation medicine

Injuries to the anterior cruciate ligament are common. Surgical reconstruction is more prevalent than ever. This review article discusses treatment of the patient following surgical reconstruction of the anterior cruciate ligament. Various phases of rehabilitation are discussed with emphasis on early return of passive motion, early weight bearing, bracing, kinetic chain exercises, neuromuscular electrical stimulation and accelerated rehabilitation. Although evidence exists for the treatment of the surgically reconstructed cruciate ligament, more is needed to better define specific timeframes for advancement. Evidence exists that many of these young individuals are not fully returning to unlimited high level activities. This review article presents some of the latest evidence regarding anterior cruciate ligament rehabilitation in an attempt to help the busy clinician understand and relate basic and clinical research to rehabilitation of a patient following reconstruction.

No association of time from surgery with functional deficits in athletes after anterior cruciate ligament reconstruction: evidence for objective return-to-sport criteria

BACKGROUND

Release for full activity and return to sport after anterior cruciate ligament reconstruction (ACLR) is often dictated by time from surgery and subjective opinion by the medical team. Temporal guidelines for return to sport may not accurately identify impaired strength and neuromuscular control, which are associated with increased risk for second injury (contralateral and/or ipsilateral limb) after ACLR in athletes.

HYPOTHESES

Athletes undergoing ACLR and returning to sport would demonstrate functional deficits that would not be associated with time from surgery.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-three male (n = 10) and female (n = 23) athletes with unilateral ACLR, who were cleared by a physician to return to their sport after surgery and rehabilitation, performed the single-legged vertical hop test for 10 seconds on a portable force plate. Matched teammates of each patient were recruited to serve as sex-, sport-, and age-matched controls (CTRL; n = 67). Maximum vertical ground-reaction force (VGRF) was measured during each single-limb landing. Single-limb symmetry index (LSI) was calculated as the ratio of the involved divided by uninvolved limb, expressed as a percentage.

RESULTS

The single-limb vertical jump height LSI was reduced in the ACLR group, 89% (95% confidence interval [CI], 83%-95%), compared with the matched CTRL group, 101% (95% CI, 96%-105%; P < .01). The LSI for VGRF normalized to potential energy achieved during flight of the hop was increased in ACLR at 112% (95% CI, 106%-117%) relative to the CTRL group at 102% (95% CI, 98%-106%; P < .01). Linear regression analysis indicated that time from surgery was not associated with limb symmetry deficits in the ACLR group (P > .05; R (2) = .002-.01).

CONCLUSION

Deficits in unilateral force development (vertical jump height) and absorption (normalized VGRF) persist in an athlete's single-limb performance after ACLR and full return to sports. These symmetry deficits appear to be independent of time after reconstruction.

CLINICAL RELEVANCE

On the basis of these results, clinicians should consider assessment of single-limb power performance in the decision-making process for return-to-sport release. Persistent side-to-side asymmetries may increase the risk of contralateral and/or ipsilateral injury.

The impact of quadriceps femoris strength asymmetry on functional performance at return to sport following anterior cruciate ligament reconstruction

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To investigate the impact of quadriceps femoris (QF) muscle strength asymmetry at the time of return to sport on self-reported function and functional performance of individuals following anterior cruciate ligament reconstruction (ACLR).

BACKGROUND

Evidence-based QF strength guidelines for return-to-sport decision making are lacking. Objective guidelines necessitate understanding the impact of QF strength deficits at the time of return to sport on function and performance.

METHODS

Fifty-five individuals (mean age, 17.3 years) who were cleared for return to sport following primary ACLR (ACLR group) and 35 uninjured individuals (mean age, 17.0 years) in a control group participated in the study. QF strength (maximum voluntary isometric contraction) was assessed, and the quadriceps index (QI) was calculated [(involved strength/uninvolved strength) × 100%]. The ACLR group was further subdivided into 2 groups, based on the QI: high quadriceps (QI of 90% or greater) and low quadriceps (QI of less than 85%). The International Knee Documentation Committee Subjective Knee Evaluation Form score was used to assess self-reported function, and hop tests were used to assess functional performance. Multivariate analysis of variance and hierarchical regression analyses were performed.

RESULTS

The individuals in the ACLR group were weaker, reported worse function, and performed worse on hop tests compared to those in the control group (P<.05). The low-quadriceps group demonstrated worse performance on the hop tests compared to the high-quadriceps group and the control group (P ≤.016). Hop test performance did not differ between the high-quadriceps and control groups (P ≥.14). QF strength predicted performance on the hop tests beyond graft type, presence of meniscus injury, knee pain, and knee symptoms.

CONCLUSION

At the time of return to sport, individuals post-ACLR who had weaker QF (QI of less than 85%) demonstrated decreased function, whereas those with minimal QF strength deficits (QI of 90% or greater) demonstrated functional performance similar to uninjured individuals. QF strength deficits predicted hop test performance beyond the influences of graft type, presence of meniscus injury, knee pain, and knee symptoms.

Accelerated versus nonaccelerated rehabilitation after anterior cruciate ligament reconstruction: a prospective, randomized, double-blind investigation evaluating knee joint laxity using roentgen stereophotogrammetric analysis

BACKGROUND

The relationship between the biomechanical dose of rehabilitation exercises administered after anterior cruciate ligament (ACL) reconstruction and the healing response of the graft and knee is not well understood.

HYPOTHESIS

After ACL reconstruction, rehabilitation administered with either accelerated or nonaccelerated programs produces the same change in the knees' 6 degrees of freedom, or envelope, laxity values.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Patients who underwent ACL reconstruction with a bone-patellar tendon-bone autograft were randomized to rehabilitation with either accelerated (19 week) or nonaccelerated (32 week) programs. At the time of surgery, and then 3, 6, 12, and 24 months later, the 6 degrees of freedom knee laxity values were measured using roentgen stereophotogrammetric analysis and clinical, functional, and patient-oriented outcome measures.

RESULTS

Eighty-five percent of those enrolled were followed through 2 years. Laxity of the reconstructed knee was restored to within the limits of the contralateral, normal side at the time of surgery (baseline) in all participants. Patients in both programs underwent a similar increase in the envelope of knee laxity over the 2-year follow-up interval (anterior-posterior translation 3.2 vs 4.5 mm, and coupled internal-external rotations 2.6° vs 1.9° for participants in the accelerated and nonaccelerated programs, respectively). Those who underwent accelerated rehabilitation experienced a significant improvement in thigh muscle strength at the 3-month follow-up (P < .05) compared with those who participated in nonaccelerated rehabilitation, but no differences between the programs were seen after this time interval. At the 2-year follow-up, the groups were similar in terms of clinical assessment, patient satisfaction, function, proprioception, and isokinetic thigh muscle strength.

CONCLUSION

Rehabilitation with the accelerated and nonaccelerated programs administered in this study produced the same increase in the envelope of knee laxity. A majority of the increase in the envelope of knee laxity occurred during healing when exercises were advanced and activity level increased. Patients in both programs had the same clinical assessment, functional performance, proprioception, and thigh muscle strength, which returned to normal levels after healing was complete. For participants in both treatment programs, the Knee Injury and Osteoarthritis Outcome Score (KOOS) assessment of quality of life did not return to preinjury levels.

Criteria-based management of an acute multistructure knee injury in a professional football player: a case report

STUDY DESIGN

Case report.

BACKGROUND

Joint stiffness, also called arthrofibrosis, remains the primary complication following any reconstructive knee surgery. Acute anterior cruciate ligament surgery, performed with concomitant multiple ligamentous repair and/or reconstruction, further increases the likelihood of developing impaired knee motion following surgery. The purpose of this case report is to present a criteria-based approach to the postoperative management of a multiligament knee injury.

CASE DESCRIPTION

A 25-year-old male professional football player sustained a contact injury to his right knee while making a tackle during a regular season game in 2007. He underwent an acute anterior cruciate ligament reconstruction, with concomitant posterolateral corner repair, biceps femoris/iliotibial band repair, lateral collateral ligament repair, and a medial meniscocapsular junction repair. He completed 17 weeks of a multiphased rehabilitation program that emphasized immediate range of motion, low-load long-duration stretching, therapeutic exercise, neuromuscular reeducation/perturbation training, plyometrics, and sport-specific functional drills. Electrical neurostimulation was implemented during the early stages of rehabilitation to control postoperative pain and to promote a steady progression of therapeutic exercise activity.

OUTCOMES

The patient was cleared to begin sport-specific activity 7 months after major multistructure reconstructive knee surgery. He began the 2008 season on the physically-unable-to-perform list, but was activated midseason and played in every game thereafter. During the 2009 and 2010 seasons, he played all regular season games and all playoff games as a starter, and continues to start as a defensive cornerback in the National Football League.

DISCUSSION

This case report highlights the clinical decision-making process and management involved in an acute multiple ligamentous knee injury/reconstruction.

LEVEL OF EVIDENCE

Therapy, level 4.

Precision of tunnel positioning in navigated anterior cruciate ligament reconstruction

PURPOSE

The aim of this study was to validate the precision of navigated tunnel positioning using a fluoroscopy-based computer-assisted technique.

METHODS

Ten human cadaveric knees were operated on under operating room conditions. After resection of the anterior cruciate ligament, referenced fluoroscopic images were acquired to plan the tunnel positions according to established radiologic measurement methods. Afterward, femoral and tibial K-wires were placed by use of navigated drill guides without arthroscopic control. Deviations between the planned and actually drilled tunnel positions at the joint level were analyzed by use of both navigated and radiologic assessment methods.

RESULTS

Navigated analysis between planned and actually drilled tunnel position showed mean deviations of 0.4 mm (range, 0 to 1 mm; SD, 0.52 mm) at the femur and 0.5 mm (range, 0 to 1 mm; SD, 0.5 mm) at the tibia. The radiologic analysis showed mean deviations for the femoral tunnel of 0.83 mm for the depth (range, 0 to 1.46 mm; SD, 0.46 mm) and 0.54 mm for the height (range, 0 to 1.08 mm; SD, 0.41 mm). At the tibia, deviation of 0.74 mm (range, 0 to 1.2 mm; SD, 0.46 mm) was found.

CONCLUSIONS

The fluoroscopy-based navigation system used in this study allows for precise tunnel positioning with deviations of 1 mm or less.

CLINICAL RELEVANCE

This technique provides accurate tunnel placement in anterior cruciate ligament surgery.

Biomechanics of the anterior cruciate ligament and implications for surgical reconstruction

Injury to the anterior cruciate ligament (ACL) is regarded as critical to the physiological kinematics of the femoral-tibial joint, its disruption eventually causing long-term functional impairment. Both the initial trauma and the pathologic motion pattern of the injured knee may result in primary degenerative lesions of the secondary stabilisers of the knee, each of which are associated with the early onset of osteoarthritis. Consequently, there is a wide consensus that young and active patients may profit from reconstructing the ACL. Several factors have been identified as significantly influencing the biomechanical characteristics and the functional outcome of an ACL reconstructed knee joint. These factors are: (1) individual choice of autologous graft material using either patellar tendon-bone grafts or quadrupled hamstring tendon grafts, (2) anatomical bone tunnel placement within the footprints of the native ACL, (3) adequate substitute tension after cyclic graft preconditioning, and (4) graft fixation close to the joint line using biodegradable graft fixation materials that provide an initial fixation strength exceeding those loads commonly expected during rehabilitation. Under observance of these factors, the literature encourages mid-to long-term clinical and functional outcomes after ACL reconstruction.

Surgery for ACL deficiency in patients over 50

PURPOSE

To compare the outcomes of arthroscopic ACL reconstruction procedure in 20 middle-aged patients (12 men and 8 women) and 20 subjects younger than 30 years (control group) at a minimum post-operative follow-up of 24 months.

METHODS

Pre- and post-operative anterior-posterior laxity was assessed by Lachman test, pivot shift test and KT1000 arthrometer at manual maximum stress. Clinical functional evaluation was assessed according to IKDC Committee (IKDC) subjective knee form, IKDC ligament standard evaluation and Lysholm score.

RESULTS

At 2 years, all variables significantly improved in both groups compared to pre-operative values (P < 0.05), with non-significant intergroup difference.

CONCLUSIONS

When faced with ACL deficiency, physiological age, condition of the knee at the time of examination, life expectancy and activity level are probably more important than chronologic age. In the present study, arthroscopic surgery for the management of ACL tear and secondary lesions provides comparable clinical outcomes in middle-aged patients and in patients aged below 30.

Autologous patellar tendon and quadrupled hamstring grafts in anterior cruciate ligament reconstruction: a prospective randomized multicenter review of different fixation methods

ACL reconstruction with bone patellar tendon bone (BPTB) grafts has been shown to produce dependable results. Recently, reconstructions with double-looped semitendinosus gracilis (DLSG) grafts have become common. The prevailing opinion is that ACL reconstruction with patellar tendon graft produces a more stable knee with more anterior knee pain than DLSG grafts, while the functional results and knee scores are similar. The present study evaluates BPTB grafts fixed with metallic interference screws and DLSG grafts fixed with Bone Mulch Screw on the femur and WasherLoc fixation on the tibia. All else being the same, there is no difference in the outcome between the two grafts and fixation methods. This is a prospective randomized multicenter study. A total of 115 patients with isolated ACL ruptures were randomized to either reconstruction with BPTB grafts fixed with metal interference screws (58 patients) or DLSG grafts (57 patients) fixed with Bone Mulch Screws and WasherLoc Screws. Follow-up was at one and two years; the latter by an independent observer. At two years, one ACL revision had been performed in each group. Eight patients in the DLSG group and one in the BPTB group underwent meniscus surgery in the follow-up period (P = 0.014). Mean Lysholm score at the two year follow-up was 91 (SD +/- 10.3) in the DLSG group and also 91 (SD +/- 10.2) in the BPTB group. Mean KT-1000 at two years was 1.5 mm in the BPTB group and 1.8 mm in the DLSG group (n.s.). At two years, four patients in the BPTB group and three in the DLSG group had a Lachman test grade 2 or 3 (n.s.). More patients in the BPTB group had pain at the lower pole of the patella (P = 0.04). Peak flexion torque and total flexion work were lower in the DLSG group at one year (P = 0.003 and P = 0.000) and total flexion work also at two years (P = 0.05). BPTB ACL reconstruction fixed with interference screws and DLSG fixed with Bone Mulch Screws on the femur and WasherLoc Screws on the tibia produce satisfactory and nearly identical outcomes. Among our patients in the DLSG group, flexion strength was lower, and more patients underwent meniscus surgery in the follow-up period. The BPTB group has more anterior knee pain.

Knee laxity measurements after anterior cruciate ligament reconstruction, using either bone-patellar-tendon-bone or hamstring tendon autografts, with special emphasis on comparison over time

The aims of the study were to analyse the change in knee laxity over time after anterior cruciate ligament (ACL) reconstruction, using either bone-patellar-tendon-bone (BPTB) or hamstring (HS) tendon autografts, and to compare the knee laxity measurements between the study groups both pre-operatively and on multiple follow-up occasions. Another aim was to compare the radiographic findings in terms of degenerative changes between the study groups. A randomised series of 71 patients, who underwent ACL reconstruction using BPTB or HS tendon autografts and interference screw fixation, were included in the study. Of these patients, 47/71 (66%) attended a clinical examination, including laxity measurements using the KT-1000 arthrometer, pre-operatively and on four post-operative occasions; 6 months, 1 year, 2 years and 7 years after the reconstruction. The BPTB group consisted of 22 patients, while there were 25 patients in the HS group. There were no significant differences in the mean side-to-side knee laxity between the BPTB and the HS group pre-operatively or at the follow-up examinations. There was a tendency towards a reduction in side-to-side knee laxity over time in both groups, measured with the KT-1000 arthrometer. The decrease was significant when analysing the injured and uninjured knee separately (injured side p < 0.001 (BPTB) and p = 0.005 (HS), uninjured side p = 0.008 and p = 0.042, respectively). Forty-four patients (BPTB 21, ST 23) underwent a radiographic assessment at the 7-year follow-up, which revealed no significant differences between the study groups in terms of osteoarthritic findings classified according to the Fairbank and Ahlbäck rating systems. In overall terms, osteoarthritis was identified in 16% (BPTB 19%; ST 13%; n.s.) according to the Ahlbäck rating system and 68% (BPTB 67%; ST 70%; n.s.) according to the Fairbank rating system. There were no significant differences in knee laxity measurements between the two study groups pre-operatively or at 7 years. A decrease in knee laxity over time was seen in both groups. There were no significant differences between the BPTB and ST groups in terms of osteoarthritic findings at 7 years.

Factors affecting patient selection of graft type in anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to assess factors associated with patient selection of graft type for anterior cruciate ligament (ACL) reconstruction.

METHODS

We retrospectively identified 1,038 patients who underwent ACL reconstruction over a 5-year period. Surgery was performed by 5 different surgeons. A questionnaire was sent to patients at a minimum of 24 months' follow-up to determine which type of graft was used, why they chose that graft, whether they were satisfied with their graft and outcome, and whether they would choose another graft and, if so, which one; it also included a visual analog scale to rate their recovery.

RESULTS

Questionnaires were received from 240 patients. The mean follow-up from the time of surgery was 41.3 months (range, 24 to 96 months). There were a variety of allografts and autografts used. Overall, allograft was used in 63.3% of patients and autograft in 35.4%. The most common factor influencing graft selection was physician recommendation (74.2%). Patients rated their recovery on average as 8.48 (+/-1.8) out of 10 on the visual analog scale (range, 0 to 10). Of the patients, 93% were satisfied with their graft selection. Only 12.7% would choose another graft if in the situation again. Of these patients, 63.3% would change from an autograft to allograft.

CONCLUSIONS

This study suggests that the most important factor for a patient choosing a graft for ACL reconstruction is physician recommendation. Our study has shown an increasing trend in our group toward the use of allograft materials for ACL reconstruction (63.3% of all graft materials selected). Of the individuals who were dissatisfied with their graft, 63% who originally chose autograft would choose allograft as a source in the future.

LEVEL OF EVIDENCE

Level III, prognostic case-control study.

Patella fracture during rehabilitation after bone-patellar tendon-bone anterior cruciate ligament reconstruction: 2 case reports

STUDY DESIGN

Case report.

BACKGROUND

Patellar fracture is a rare but significant complication following anterior cruciate ligament (ACL) reconstruction when using a bone-patellar tendon-bone (BPTB) autograft. The purpose of these case reports is to describe 2 cases in which patellar fracture occurred during rehabilitation after ACL reconstruction using a BPTB.

CASE DESCRIPTION

Both patients were 23-year-old males referred for rehabilitation after ACL reconstruction using a BPTB autograft. They were both progressing satisfactorily in rehabilitation until sustaining a fracture of the patella. One fracture occurred during the performance of the eccentric phase of a knee extension exercise during the sixth week of rehabilitation (7 weeks postsurgery), whereas the other fracture occurred during testing of the patient is quadriceps maximum voluntary isometric contraction in the ninth week of rehabilitation (10 weeks postsurgery). Both patients were subsequently treated with open reduction and internal fixation of the patella.

DISCUSSION

During rehabilitation following ACL reconstruction using BPTB autograft, clinicians should consider the need to balance the sometimes-competing goals of improving quadriceps strength while providing protection to the healing graft, minimization of patellofemoral pain, and protection of the patellar donor site.

Anterior cruciate ligament reconstruction associated with extra-articular tenodesis: A prospective clinical and radiographic evaluation with 10- to 13-year follow-up

BACKGROUND

This study was undertaken to prospectively analyze, at a mean 11-year follow-up, the clinical and radiographic outcomes in patients undergoing the authors' intra-articular anterior cruciate ligament reconstructive procedure with extra- articular augmentation, and to compare these data with those at 5-year follow-up.

PURPOSE

The clinical and radiographic outcomes in patients undergoing anterior cruciate ligament reconstruction were analyzed at a mean 11-year follow-up.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The authors studied 54 of 60 consecutive high-level sports patients who underwent their anterior cruciate ligament reconstruction technique between 1993 and 1995. The surgical technique uses the hamstring tendons with intact tibial insertions for intra-articular double-stranded reconstruction plus an extra-articular plasty (augmentation) performed with the remnant part of the tendons. Clinical and radiographic evaluations were performed.

RESULTS

After 11 years, the International Knee Documentation Committee score demonstrated good or excellent results (A and B) in 90.7% of patients. Ligament arthrometry using the KT-2000 arthrometer demonstrated that only 2 patients had >5 mm manual maximum side-to-side difference in laxity. The mean Tegner activity score was 4.5, while the mean Lysholm score was 97.3 and the mean subjective score was 90.0%. Radiographic evaluation demonstrated progressive joint narrowing only for the 20 patients having concomitant medial meniscal surgery.

CONCLUSION

The original technique demonstrates highly satisfactory results. Factors negatively affecting the outcomes are meniscectomy and laxity. In this series, anterior cruciate ligament reconstruction with lateral plasty shows maintenance of knee stability at long-term follow-up. Knee osteoarthritis after anterior cruciate ligament reconstruction with extra-articular tenodesis does not appear to be greater than after anterior cruciate ligament reconstructions without extra-articular augmentation as reported in historical controls.

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.

Neuromuscular training techniques to target deficits before return to sport after anterior cruciate ligament reconstruction

Surgical intervention and early-phase rehabilitation after anterior cruciate ligament (ACL) reconstruction have undergone a relatively rapid and global evolution over the past 25 years. Despite the advances that have significantly improved outcomes, decreases in healthcare coverage (limited visits allowed for physical therapy) have increased the role of the strength and conditioning specialist in the rehabilitation of athletes returning to sport after ACL reconstruction. In addition, there is an absence of standardized, objective criteria to accurately assess an athlete's ability to progress through the end stages of rehabilitation and safely return to sport. The purpose of this Scientific Commentary is to present an example of a progressive, end-stage return to sport protocol that is targeted to measured deficits of neuromuscular control, strength, power, and functional symmetry that are rehabilitative landmarks after ACL reconstruction. The proposed return to sport training protocol incorporates quantitative measurement tools that will provide the athlete with objective feedback and targeted goal setting. Objective feedback and targeted goal setting may aid the strength and conditioning specialist with exercise selection and progression. In addition, a rationale for exercise selection is outlined to provide the strength and conditioning specialist with a flexible decision-making approach that will aid in the modification of return to sport training to meet the individual athlete's abilities and to target objectively measured deficits. This algorithmic approach may improve the potential for athletes to return to sport after ACL reconstruction at the optimal performance level and with minimized risk of reinjury.

Bone-patella tendon-bone autograft anterior cruciate ligament reconstruction

The anterior cruciate ligament (ACL) serves an important stabilizing and biomechanical function for the knee. Reconstruction of the ACL remains one of the most commonly performed procedures in the field of sports medicine. Reconstruction of the ACL with bone-patella tendon-bone (BPTB) autograft secured with interference screw fixation has been the historical reference standard and remains the benchmark against which other methods are gauged. This article reviews the reconstruction of the ACL with BPTB autograft including the surgical technique, rationale for BTPB use, and outcomes.

Pathological changes of human ligament after complete mechanical unloading

OBJECTIVE

To investigate the pathologic changes with a time sequence among patients with injured ligaments after complete mechanical unloading, based on a human anterior cruciate ligament (ACL) model.

DESIGN

Pathologic examinations were done on remnants of completely ruptured ACLs at various times up to 14 wks after injury on 31 patients and on normal ACLs from five cadaver donors. Testing variables included fibroblast density, crimp amplitude, and crimp nuclear shape.

RESULTS

Sequential changes were observed: Fibroblast density significantly increased within 5-6 wks of unloading. By 7-8 wks, crimp amplitude significantly decreased, accompanied by formation of irregular fiber patterns and fragments. This was followed by crimp wavelength and nuclear shape change within 9-14 wks.

CONCLUSIONS

These pathologic findings suggest that the ACL undergoes significantly deleterious changes from 5 to 6 wks after mechanical unloading. This study may emphasize the important concept of early implementation of mechanical force in rehabilitation programs for patients with injured ligaments.

Early active extension after anterior cruciate ligament reconstruction does not result in increased laxity of the knee

If permission of full active and passive extension immediately after an anterior cruciate ligament (ACL) reconstruction will increase the post-operative laxity of the knee has been a subject of discussion. We investigated whether a post-operative rehabilitation protocol including active and passive extension without any restrictions in extension immediately after an ACL reconstruction would increase the post-operative anterior-posterior knee laxity (A-P laxity). Our hypothesis was that full active and passive extension immediately after an ACL reconstruction would have no effect on the A-P laxity and clinical results up to 2 years after the operation. Twenty-two consecutive patients (14 men, 8 women, median age 21 years, range 17-41) were included. All the patients had a unilateral ACL rupture and no other ligament injuries or any other history of previous knee injuries. The surgical procedure was identical in all patients and one experienced surgeon operated on all the patients, using the bone-patellar tendon-bone autograft. The post-operative rehabilitation programme was identical in both groups, except for extension training during the first 4 weeks post-operatively. The patients were randomly allocated to post-operative rehabilitation programmes either allowing (Group A, n=11) or not allowing [Group B (30 to -10 degrees ), n=11] full active and passive extension immediately after the operation. They were evaluated pre-operatively and at 6 months and 2 years after the reconstruction. To evaluate the A-P knee laxity, radiostereometric analysis (RSA) and KT-1000 arthrometer (KT-1000) measurements were used, range of motion, Lysholm score, Tegner activity level, the International Knee Documentation Committee (IKDC) evaluation system and one-leg-hop test quotient were used. Pre-operatively, the RSA measurements revealed side-to-side differences in Group A of 8.6 mm (2.3-15.4), median (range) and in Group B of 7.2 mm (2.2-17.4) (n.s.). The corresponding KT-1000 values were for Group A, 2.0 mm (0-8.0) and Group B, 4.0 mm (0-10.0) (n.s.). At 2 years, the differences between the two groups were minimal, regardless of the method that had been used. The RSA measurements in Group A were 2.7 mm (0-10.7) and in Group B 2.8 (-1.8 to 9.5). The KT-1000 values were for Group A, 1.0 mm (-1.5 to 3.5), and for Group B, 0.5 mm (-1.0 to 4.0), without any significant differences between the groups. Nor did the Lysholm score, Tegner activity level, IKDC or one-leg-hop test differ. Early active and passive extension training, without any restrictions in extension, immediately after an ACL reconstruction using bone-patellar tendon-bone graft did not increase post-operative knee laxity up to 2 years after the ACL reconstruction.

Prospective and randomized evaluation of ACL reconstruction with three techniques: a clinical and radiographic evaluation at 5 years follow-up

A variety of graft sources have been used for ACL reconstruction to improve functions and kinematics in ACL deficient knees. The two most commonly used autogenous grafts are the central third of the patellar tendon and the hamstring tendon constructs. The choice of different grafts and different construct influence the final clinical outcome of ACL reconstruction. The 3 groups, of 25 patients each, were generated by choosing the technique (PT tendon, 4 strand hamstring, and single hamstring plus extraarticular plasty) to utilize and followed for 5 years, with an alternate systematic sampling. Our comparison has shown significant kneeling pain in the patellar tendon with respect to the groups with hamstrings techniques. Single hamstring plus extraarticular plasty achieved subjective score significantly higher with respect to the other two groups as well as for the time to resume sport. The study confirms that patellar tendon and hamstring can be equivalent options for ACL reconstruction. This study demonstrated that a superior outcome as far as subjective clinical findings were concerned, was obtained in group III. Patients in the latter group were also able to return to sports sooner than those in the bone-patellar tendon graft group and the four-strand hamstring group.

The evolution of osteoarthritis in 103 patients with ACL reconstruction at 17 years follow-up

AIM

To evaluate the functional and radiological outcome of a bone-tendon-bone anterior cruciate ligament reconstruction, at long-term follow-up.

METHODS

A retrospective study of 148 patients, of which 103 were available for long-term follow-up. Complete functional and radiological evaluation (International Knee Documentation Committee scale) were performed in 89 out of the 103 patients [Anderson AF. Rating scales. In: Fu FH, Harner CD, Vince KG, (Eds.). Knee Surgery, Baltimore, Williams and Wilkins vol. 1, 1994; 12, pp. 275-296].

RESULTS

The mean follow-up time was 17.4 years. Subjectively, 88% of the patients were very satisfied or satisfied. According to the IKDC score 55% had type A symptoms, 29% type B, 12% type C, and 4% type D. The IKDC ligament evaluation showed 14.9% type A, 44.8% type B, 35.8% type C, and 4.5% type D. At the review 22.7% had a narrowing <50% (C) and 4.7% a narrowing >50% (D). Onset of osteoarthritis showed an association with the status of the medial meniscus. Knees with a preserved (healthy or sutured) medial meniscus had a significantly (p < 0.05) better radiological outcome. Among these, 9% had a joint space narrowing <50% (C) and 2% had a narrowing >50% (D). Medial meniscectomy, residual laxity, and femoral chondral defects were associated with osteoarthritis.

CONCLUSION

The outcome of anterior cruciate ligament reconstruction plus extra-articular tenodesis is good in the very long term, particularly in knees with a preserved medial meniscus.

Post-operative use of knee brace in bone-tendon-bone patellar tendon anterior cruciate ligament reconstruction: 5-year follow-up results of a randomized prospective study

Sixty patients were prospectively randomized to brace and no-brace groups after bone-tendon-bone patellar tendon anterior cruciate ligament (ACL) reconstruction. The brace group wore a rehabilitation knee brace for 12 weeks post-operatively, while the no-brace group was mobilized immediately, and crutches were discarded 2 weeks post-operatively. The groups were comparable with respect to age, gender, time from injury to surgery and concomitant injuries. There were no differences either pre-operatively or 5 years post-operatively (80% of patients reviewed) between the groups in terms of the knee score (Lysholm), activity level (Tegner), degree of laxity or isokinetic peak muscle torque. Thus it appears that knee braces are not needed in the post-operative rehabilitation after ACL reconstruction with the patellar tendon graft.

Rehabilitation after anterior cruciate ligament reconstruction: criteria-based progression through the return-to-sport phase

Rehabilitation following anterior cruciate ligament (ACL) reconstruction has undergone a relatively rapid and global evolution over the past 25 years. However, there is an absence of standardized, objective criteria to accurately assess an athlete's ability to progress through the end stages of rehabilitation and safe return to sport. Return-to-sport rehabilitation, progressed by quantitatively measured functional goals, may improve the athlete's integration back into sport participation. The purpose of the following clinical commentary is to introduce an example of a criteria-driven algorithm for progression through return-to-sport rehabilitation following ACL reconstruction. Our criteria-based protocol incorporates a dynamic assessment of baseline limb strength, patient-reported outcomes, functional knee stability, bilateral limb symmetry with functional tasks, postural control, power, endurance, agility, and technique with sport-specific tasks. Although this algorithm has limitations, it serves as a foundation to expand future evidence-based evaluation and to foster critical investigation into the development of objective measures to accurately determine readiness to safely return to sport following injury.

Treatment of anterior cruciate ligament injuries, part 2

Anterior cruciate ligament tears, common among athletes, are functionally disabling; they predispose the knee to subsequent injuries and the early onset of osteoarthritis. A total of 3810 studies published between January 1994 and the present were identified and reviewed to determine the current state of knowledge regarding the treatment of anterior cruciate ligament injuries. Part 1 of this article focused on studies pertaining to the biomechanical behavior of the anterior cruciate ligament, the prevalence of and risk factors for injuries related to it, the natural history of the ligament-deficient knee, injuries associated with anterior cruciate ligament disruption, indications for the treatment of anterior cruciate ligament injuries, as well as nonoperative and operative treatments. Part 2 includes technical aspects of anterior cruciate ligament surgery, bone tunnel widening, graft healing, rehabilitation after anterior cruciate ligament reconstruction, and the effects of sex, age, and activity level on the outcome of such reconstructive surgery.

Anterior cruciate ligament reconstruction in patients older than 40 years: allograft versus autograft patellar tendon

BACKGROUND

Anterior cruciate ligament reconstruction is the recommended treatment for patients of all ages who are involved in sports and have symptoms of knee instability.

HYPOTHESIS

In patients older than 40 years, allograft reconstruction will have better subjective and objective results than autograft reconstruction, proving allograft to be a better graft source for this patient population.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The authors identified 63 patients meeting the criteria for this study, including 38 patients in the allograft group and 25 patients in the autograft group. All patients were older than 40 years and had at least 2 years' follow-up. Objective parameters included preinjury and postoperative Tegner activity rating scale and Lysholm scores, range of motion, thigh circumference differences, side-to-side difference at maximum manual force in anterior displacement by KT-1000 arthrometer, and clinical examination for Lachman and pivot-shift tests. Using a 15-point visual analog scale, the authors performed subjective evaluations.

RESULTS

Both groups' Tegner activity rating scale scores returned to preoperative levels. Visual analog scales and range of motion data were similar for both groups. KT-1000 arthrometer data showed a mean maximum difference of 1.46 mm for the allograft group and 0.10 mm for the autograft group (P = .398). Three patients in the allograft group showed greater than 5 mm difference, compared with none in the autograft group. There was 1 clinical failure in the allograft group. In the allograft group, 57% of patients had returned to sports by 6 months versus 25% of patients in the autograft group (P = .005), increasing to 71% and 43%, respectively, at final follow-up (P = .127).

CONCLUSION

Allograft bone-patellar tendon-bone advantages include quicker return to sporting activities; disadvantages include increased laxity and higher incidence of failure. The advantage of autograft bone-patellar tendon-bone is that it appears to be a tighter graft. The authors found that allograft was not a superior graft source in this patient population, leading them to offer both options.

Rehabilitation after anterior cruciate ligament reconstruction: a prospective, randomized, double-blind comparison of programs administered over 2 different time intervals

BACKGROUND

There are adverse effects associated with immobilization of the knee after anterior cruciate ligament reconstruction, yet very little is known about how much activity will promote adequate rehabilitation without permanently elongating the graft, producing graft failure, or creating damage to articular cartilage.

HYPOTHESIS

Rehabilitation with either an accelerated or nonaccelerated program produces no difference in anterior-posterior knee laxity, clinical assessment, patient satisfaction, functional performance, and the synovial fluid biomarkers of articular cartilage metabolism.

STUDY DESIGN

Randomized controlled clinical trial; Level of evidence, 1.

METHODS

Twenty-five patients who tore their anterior cruciate ligament were enrolled and underwent anterior cruciate ligament reconstruction. Patients were randomized to accelerated rehabilitation or nonaccelerated rehabilitation. At the time of surgery and 3, 6, 12, and 24 months later, measurements of anterior-posterior knee laxity, clinical assessment, patient satisfaction, functional performance, and cartilage metabolism were completed.

RESULTS

At the 2-year follow-up, there was no difference in the increase of anterior knee laxity relative to the baseline values that were obtained immediately after surgery between the 2 groups (2.2-mm vs 1.8-mm increase relative to the normal knee). The groups were similar in terms of clinical assessment, patient satisfaction, activity level, function, and response of the bio-markers. After 1 year of healing, synthesis of collagen and turnover of aggrecan remained elevated in both groups.

CONCLUSION

Anterior cruciate ligament reconstruction with a bone-patellar tendon-bone graft followed by either accelerated or nonaccelerated rehabilitation produces the same increase of anterior knee laxity. Both programs had the same effect in terms of clinical assessment, patient satisfaction, functional performance, and the biomarkers of articular cartilage metabolism. There is concern that the cartilage biomarkers remained elevated for an extended period.

Return to official Italian First Division soccer games within 90 days after anterior cruciate ligament reconstruction: a case report

STUDY DESIGN

Case report.

BACKGROUND

To present the rehabilitative course, decision-making, and clinical milestones that allowed a top-level professional soccer player to return to full competitive activity 90 days after surgery.

CASE DESCRIPTION

The patient was a 35-year-old forward player who sustained an isolated complete tear of the left anterior cruciate ligament (ACL) in the midst of the competitive 2001-2002 season. He was in contention for a position on the Italian World Cup Team that was to be played 135 days after his injury, only if he demonstrated that he could return to play at the highest level before the team was selected. The patient underwent an arthroscopically assisted ACL reconstruction with a double-loop semitendinosus-gracilis autograft 4 days after the injury. Eight days after surgery he began rehabilitation at a rate of 2 sessions a day, 5 days a week, plus 1 session every Saturday morning. These sessions were performed in a pool for aquatic exercises, in a gymnasium for flexibility, coordination, and strength exercises, and on a soccer field for recovery of technical and tactical skills, with continuous monitoring of training intensity.

OUTCOMES

The surgical technique and the progressive rehabilitation program allowed the patient to play for 20 minutes in an official First Division soccer game 77 days after surgery and to play a full game 90 days after surgery. Eighteen months postsurgery, the player had participated in 62 First Division matches, scoring 26 times, and had received no further treatment for his knee.

DISCUSSION

This case report suggests that early return to high-level competition after ACL reconstruction is possible in some instances. Some factors that may have favored the early return include optimal physical fitness before surgery, a strong psychological determination, an isolated ACL lesion, a properly placed and tensioned graft, a personalized progression of volume and intensity of exercise loads, and an appropriate density of rehabilitative training consisting of a mix of gymnasium, pool, and field exercises.

Contribution of biomechanics, orthopaedics and rehabilitation: the past present and future

Biomechanics is a field that has a very long history. From its beginnings in ancient Chinese and Greek literature, the field of orthopaedic biomechanics has grown in the areas of biomechanics of bone, articular cartilage, soft tissues, upper extremities, spine and so on. Bioengineers in collaboration with orthopaedic surgeons have applied biomechanical principles to study clinically relevant problems, improving patient treatment and outcome. In the past 30 years, my colleagues and I have focused our research on the biomechanics of musculoskeletal soft tissues, ligaments and tendons in particular. Therefore, in this review article, the function of the knee ligaments and the associated homeostatic responses secondary to immobilisation and exercise will be described. Research on healing of the medial collateral ligament (MCL) of the knee and possible future approaches in improving the healing of the knee ligaments will be presented. Finally, improvement of the understanding of ligament reconstruction, specifically of the anterior cruciate ligament (ACL), through the use of robotics technology will be included. Throughout the manuscript, specific scientific findings that have guided or changed the clinical management of injury to these soft tissues will be emphasised.

Biomechanics of knee ligaments: injury, healing, and repair

Knee ligament injuries are common, particularly in sports and sports related activities. Rupture of these ligaments upsets the balance between knee mobility and stability, resulting in abnormal knee kinematics and damage to other tissues in and around the joint that lead to morbidity and pain. During the past three decades, significant advances have been made in characterizing the biomechanical and biochemical properties of knee ligaments as an individual component as well as their contribution to joint function. Further, significant knowledge on the healing process and replacement of ligaments after rupture have helped to evaluate the effectiveness of various treatment procedures. This review paper provides an overview of the current biological and biomechanical knowledge on normal knee ligaments, as well as ligament healing and reconstruction following injury. Further, it deals with new and exciting functional tissue engineering approaches (ex. growth factors, gene transfer and gene therapy, cell therapy, mechanical factors, and the use of scaffolding materials) aimed at improving the healing of ligaments as well as the interface between a replacement graft and bone. In addition, it explores the anatomical, biological and functional perspectives of current reconstruction procedures. Through the utilization of robotics technology and computational modeling, there is a better understanding of the kinematics of the knee and the in situ forces in knee ligaments and replacement grafts. The research summarized here is multidisciplinary and cutting edge that will ultimately help improve the treatment of ligament injuries. The material presented should serve as an inspiration to future investigators.