Joint laxity and isokinetic thigh muscle strength characteristics after anterior cruciate ligament reconstruction: bone patellar tendon bone versus quadrupled hamstring autografts

Bone-patellar tendon-bone versus two- and four-strand hamstring tendon autografts for ACL reconstruction in young adults: a Bayesian network meta-analysis

Bone-patellar tendon-bone (BPTB), two- and four-strand hamstring tendon (4SHT and 2SHT, respectively) are the most common autografts used for anterior cruciate ligament (ACL) reconstruction. The present study compared BPTB, 2SHT, and 4SHT for ACL reconstruction in terms of joint laxity, patient reported outcome measures (PROMs), rate of failure and anterior knee pain (AKP). The time to return to sport and the peak torque between the autografts were also compared. Finally, prognostic factors leading to worse outcomes were also investigated. It was hypothesized that all grafts yield similar proprieties in terms of joint laxity, patient reported outcome measures (PROMs) and rate of failure, but that the BPTB autograft causes a greater rate of anterior knee pain (AKP). The literature search was conducted. All clinical trials comparing BTPB and/or 2SHT, and/or 4SHT were accessed. Grafts other than BTPB and/or 4SHT and/or 2SHT were not considered. Articles reporting outcomes of allografts or synthetic grafts were not eligible, nor were those concerning revision settings. Articles reporting ACL reconstruction in patients with multi-ligament damage were also not eligible. Data from 95,575 procedures were retrieved. The median length of follow-up was 36 months. The median age of the patients was 27.5 years. With regard to joint laxity, similarity was found in terms of Lachman and Pivot shift tests between all three autografts. The BPTB demonstrated the greatest stability in terms of instrumental laxity. BPTB demonstrated the greatest PROMs. BPTB demonstrated the greatest rate of AKP, while AKP in 2SHT and 4SHT was similar. Concerning failure, statistically significant inconsistency was found (P = 0.008). The 4SHT demonstrated the quickest return to sport, followed by BPTB, and 2SHT. There was evidence of a negative association between the time span between injury to surgery, Lysholm score (P = 0.04), and Tegner scale (P = 0.04). Furthermore, there was evidence of a weak positive association between the time span between injury to surgery and return to sport (P = 0.01). BPTB may result in lower joint laxity, greater PROMs, and greater peak flexion torque compared to 2SHT and 4SHT autografts. On the other hand, BPTB reported the lowest peak extension torque and the greatest rate of AKP. Finally, a longer time span between injury and surgery negatively influences outcome.

Current trends in anterior cruciate ligament surgery. A worldwide benchmark study

OBJECTIVES

To benchmark current trends on anterior cruciate ligament reconstruction (ACLR) surgery.

METHODS

The largest worldwide ACLR survey to date was performed during May 2020, targeted to reach representation of all continents. It was submitted electronically to all International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports surgeons (n = 3,026), asking those who perform ACLR to respond.

RESULTS

With a final sample size of 2,107, the overall response rate was 69.6%. Median years of practice as orthopaedic surgeon was 15 (range 1-52) and 49.6% of all respondents were defined as high-volume surgeons (>50 ACLR annually). Hamstrings tendon autograft was the preferred graft for primary ACLR (80.3%) and the medial portal femoral drilling was the most frequently used technique (78.5%). Cortical buttons (82.7%) and bioabsorbable screws (62.7%) were the preferred fixation methods for hamstring tendon autograft ACLR in femur and tibia, respectively. Metallic screws (45.2%) were the preferred fixation methods for bone patellar tendon bone autograft in femur and tibia. Most of the respondents routinely used pre-tensioning techniques for their graft preparation (63.8%), but less than half of surgeons preferred antibiotic soaking of the grafts (45.3%). The preferred knee position for graft fixation was 10-30° of knee flexion and neutral rotation (57.0%). The addition of anterolateral augmentation (or extra-articular tenodesis) was infrequent in primary and isolated ACLR (10.0%), but a statistically significant raise was seen for revision surgeries (20.0%). Most used brace in the initial postoperative rehabilitation (54.9%) and the time to allow patients to fully resume sports was at an average of 8.9 ± 2.0 months. Treatment algorithm of paediatric ACL injuries exhibited a low consensus among the respondents.

CONCLUSION

This worldwide survey benchmarks the current trends in ACL reconstruction, achieving the largest participation of surgeons to date. Among the great variety of options available for ACL reconstructions, surgeons' preferences showed some differences according to their location and expertise. Reporting trends in practice, and not only the evidence, is important to medical education and providing patients the safest care possible. This is a Level V, expert opinion study.

Deficits in Contralateral Limb Strength Can Overestimate Limb Symmetry Index After Anterior Cruciate Ligament Reconstruction

Purpose

To evaluate whether contralateral limb strength represents a dynamic, rather than static, data point after anterior cruciate ligament reconstruction (ACL-R).

Methods

Patients who underwent isolated ACL-R at a single institution were identified. Patients completed an institutional Lower-Extremity Assessment Protocol (LEAP) testing protocol at 6 and 9 months postoperatively. Extension strength and flexion strength of the ipsilateral and contralateral limbs and limb symmetry index (LSI) were compared between the 6- and 9-month testing outcomes. Subgroup analysis compared patients demonstrating less than or greater than 10% change in contralateral limb flexion and extension strength between 6 and 9 months postoperatively.

Results

A total of 144 subjects were included in this study. On average, contralateral limb flexion and extension strength increased 2-4% between 6 and 9 months postoperatively. However, the contralateral limb increased >10% from 6 to 9 months in extension and flexion strength in 35/144 (24.3%) and 55/144 (38.2%) of patients, respectively. The cohort with >10% change between 6 and 9 months had significantly weaker contralateral extension and flexion strength at 6 months compared to the cohort that demonstrated <10% change (extension: 2.00 vs 2.39; P < .001; flexion: 0.84 vs 1.08; P < .001), but similar ipsilateral limb performance. Therefore, the >10% change cohort had a significantly greater LSI at 6 months compared to the <10% change cohort (67.3% vs 59.4%; P = .006). No demographic or operative factors correlated with which patients demonstrated >10% flexion or extension strength changes of the contralateral limb.

Conclusion

A large percentage of patients demonstrate significant changes in their contralateral limb flexion and extension strength between 6 and 9 months postoperatively that result from an initial contralateral limb strength deficit. This may limit the utility of the contralateral limb as a control for comparison to the operative extremity during return to sport assessment.

Home-Based Nonoperative-Side Quadriceps Neuromuscular Electrical Stimulation Prevents Muscle Weakness Following Anterior Cruciate Ligament Reconstruction

We compared the effectiveness of a home-based neuromuscular electrical stimulation (NMES) program applied to the quadriceps of the nonoperative side against sham-NMES as a complement to standard rehabilitation on knee extensor neuromuscular function in patients following anterior cruciate ligament (ACL) reconstruction. Twenty-four patients completed the 6 week NMES (n = 12) and sham-NMES (n = 12) post-operative interventions and were tested at different time points for neuromuscular function and self-reported knee function. Isometric, concentric, and eccentric strength deficits (muscle weakness) increased significantly from pre-surgery to 24 weeks post-surgery in the sham-NMES group (p < 0.05), while no significant changes were observed in the NMES group. On the stimulated (nonoperative) side, quadriceps voluntary activation and muscle thickness were respectively maintained (p > 0.05) and increased (p < 0.001) as a result of the NMES intervention, contrary to sham-NMES. Self-reported knee function improved progressively during the post-operative phase (p < 0.05), with no difference between the two groups. Compared to a sham-NMES intervention, a 6 week home-based NMES program applied to the quadriceps of the nonoperative side early after ACL reconstruction prevented the occurrence of knee extensor muscle weakness 6 months after surgery. We conclude that nonoperative-side NMES may help counteract muscle weakness after ACL reconstruction.

Effect of Concomitant Meniscal Tear on Strength and Functional Performance in Young Athletes 6 Months After Anterior Cruciate Ligament Reconstruction With Hamstring Autograft

Background:

The effect of concomitant meniscal tears, and their associated treatment, on strength and functional recovery after anterior cruciate ligament reconstruction (ACLR) has not been adequately investigated in young populations.

Hypothesis:

Concomitant meniscal tears, treated with or without repair, would not adversely affect strength, balance, or functional hop test performance at 6 months postoperatively.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

The authors retrospectively analyzed return-to-sports (RTS) assessments prospectively collected 6 months after ACLR with hamstring autograft in 165 patients ≤25 years of age. Descriptive, surgical, and RTS testing data were analyzed, and subgroups were compared using analysis of covariance models designed to assess the effects of sex, meniscal tear, and meniscal repair on RTS performance.

Results:

Included were 115 female (70%) and 50 male (30%) patients with a mean age of 16.4 years (range, 12.3-25 years). Of these patients, 58% had concomitant meniscal tears (59% lateral, 27% medial, 14% lateral + medial), comprising 53% of the female and 70% of the male patients. The authors treated 61% of the tears with repair, with range of motion (ROM) and weightbearing limitations imposed within the first 6 weeks postoperatively, whereas 39% were treated with partial meniscectomy, rasping, or trephination (no ROM or weightbearing restrictions). The mean deficit in hamstring strength at 6 months postoperatively was significantly greater in the meniscal tear group than in those without a tear (32.3% vs 24.6%; P = .028). The meniscal repair group had greater hamstring strength deficits than the group with meniscectomy, rasping or trephination (34.3% vs 26.2%; P = .023). Performance on dynamic balance and functional hop tests was similar among all meniscus subgroups. There were no sex-based effects on any subgroup comparisons.

Conclusion:

At 6 months postoperatively, both young male and young female patients who underwent ACLR with hamstring autograft demonstrated significant hamstring strength deficits compared with their nonoperative leg. The presence of a meniscal tear and subsequent repair, or its related rehabilitation restrictions, appears to have adverse effects on the postoperative recovery of hamstring strength.

Commonly used clinical criteria following ACL reconstruction including time from surgery and isokinetic limb symmetry thresholds are not associated with between-limb loading deficits during running

OBJECTIVES

We included objective measures of gait and functional assessments to examine their associations in athletes who had recently commenced running after ACL reconstruction.

DESIGN

Cross-sectional.

SETTING

Sports medicine.

PARTICIPANTS

65 male athletes with a history of ACL reconstruction.

MAIN OUTCOME MEASURES

Time from surgery, isokinetic knee extension/flexion strength (60°/s), and peak vertical ground reaction force (pVGRF) measured during running using an instrumented treadmill. We also investigated if a range of recommended isokinetic thresholds (e.g. > 70% quadriceps limb symmetry index) affected the magnitude of pVGRF asymmetry during running.

RESULTS

There were significant relationships between quadriceps (r = 0.50) and hamstrings (r = 0.46) peak torque and pVGRF. Quadriceps peak torque explained a quarter of the variance in pVGRF (R² = 0.24; p < 0.001). There was no association was between running pVGRF and time from surgery. Between-group differences in running pVGRF LSI% were trivial (d < 0.20) for all quadriceps and hamstring peak torque LSI thresholds.

CONCLUSIONS

Current clinical criteria including time from surgery and isokinetic strength limb symmetry thresholds were not associated with lower pVGRF asymmetry measured during running. Quadriceps strength is important, but 'minimum symmetry thresholds' should be used with caution.

Outcome of bone-patellar tendon-bone vs hamstring tendon autograft for anterior cruciate ligament reconstruction: A meta-analysis of randomized controlled trials with a 5-year minimum follow-up

BACKGROUND

Many systematic reviews have compared the short-term outcomes of anterior cruciate ligment (ACL)reconstruction with hamstring and patellar tendon autograft,but few differences have been observed. The purpose of this meta-analysis was to compare the medium-term outcome of bone-patellar tendon-bone and hamstring tendon autograft for anterior cruciate ligament reconstruction in terms of clinical function, knee stability, postoperativecomplications, and osteoarthritis changes.

METHODS

This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed, Embase, and the Cochrane Library databases were searched from inception to November 2, 2019. This meta-analysis included only randomized controlled trials that compared BPTB and HT autografts for ACL reconstruction with a 5-year minimum follow-up. The Cochrane Collaboration's risk-of-bias tool was used to estimate the risk-of-bias for all included studies. RevMan 5.3 software was used to performed statistical analysis of the outcomes.

RESULTS

Fifteen RCTs, involving 1298 patients (610 patients in the BPTB group and 688 patients in the HT group) were included. In terms of clinical function, no significant difference was found in the objective International Knee Documentation Committee score (OR = 0.94, 95%CI: 0.64-1.37, P = .75), Lysholm knee score (MD = -2.26, 95%CI: -4.56 to 0.05, P = .06), return to preinjury activity level (OR = 1.01, 95%CI: 0.67-1.52, P = .96), and Tegner activity level (OR = 0.03, 95%CI: -0.36 to 0.41, P = .89). There was no statistically significant difference in the Lachman test (OR = 0.86, 95%CI: 0.5-1.32, P = .50), pivot-shift test (OR = 0.68, 95%CI: 0.44-1.06, P = .09), and side-to-side difference (MD = -0.32, 95%CI: -0.81 to 0.16, P = .19). As for postoperative complications and OA changes, there were no statistically significant difference in flexion loss (OR = 1.09, 95%CI: 0.47-2.54, P = .85) and OA changes (OR = 0.76, 95%CI: 0.52-1.10, P = .15), but we found significant differences in favor of the HT group in the domains of kneeling pain (OR = 1.67, 95%CI: 1.04-2.69, P = .03), anterior knee pain (OR = 2.90, 95%CI: 1.46-5.77, P = .002), and extension loss (OR = 1.75, 95%CI: 1.12-2.75, P = .01). There was a significant difference in favor of the BPTB group in the domain of graft failure (OR = 0.59, 95%CI: 0.38-0.91, P = .02).

CONCLUSIONS

Based on the results above, HT autograft is comparable with the BPTB autograft in terms of clinical function, postoperative knee stability, and OA changes, with a medium-term follow-up. The HT autograft for ACL reconstruction carries a lower risk of complications, such as anterior knee pain, kneeling pain, and extension loss, but an increased incidence of graft failure. Patients should be informed of the differences when deciding on graft choice with their physician.

Comparative Efficacy of Graft Options in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Network Meta-Analysis

Purpose

To evaluate the effectiveness of various graft options for anterior cruciate ligament reconstruction using network meta-analysis.

Methods

A medical literature search was conducted of PubMed, the Cochrane Library, Embase, SCOPUS, and Web of Science from their inception through March 1, 2019. The outcomes, including International Knee Documentation Committee (IKDC) form, Lachman test, Lysholm score, Pivot shift test, and Tegner score, were evaluated among graft options. Data extraction was carried out according to inclusion and exclusion criteria, and a network meta-analysis was performed using STATA 14.0.

Results

A total of 45 trials with 3992 patients were included. The forest plots revealed no significant differences in IKDC, Lysholm, or Tegner score among the grafts. In Lachman score, a significant difference was found in the comparisons of hamstring tendon allograft (HT-AL) versus patellar tendon autograft (PT-AU) and HT-AL versus hamstring tendon autograft (HT-AU). In pivot shift test, PT-AU was superior to all the other grafts, and quadriceps tendon autograft (QT-AU) was superior to HT-AL and artificial ligament (Art-L) in the number of cases with negative results. According to surface under the cumulative ranking area (SUCRA), PT-AU had the highest probability to be the best intervention in Lachman test and Tegner score; tibialis anterior tendon allograft (TA-AL) in IKDC and Lysholm score; and QT-AU in pivot shift test. Based on the cluster analysis of SUCRA, PT-AU was considered the most appropriate intervention by IKDC and Lachman test.

Conclusion

This study suggests that PT-AU may be the most appropriate graft for ACL reconstruction according to IKDC and Lachman test results.

Level of Evidence

Level I, network meta-analysis of randomized controlled trials.

Females Have Earlier Muscle Strength and Functional Recovery After Bridge-Enhanced Anterior Cruciate Ligament Repair

Background: While a sex effect on outcomes following anterior cruciate ligament (ACL) reconstruction surgery has been previously documented, less is known following bridge-enhanced ACL repair (BEAR). We hypothesized that female sex would have significantly worse early functional outcomes and higher retear rates following primary repair of the ACL enhanced with a tissue-engineered scaffold. Methods: Sixty-five patients (28 males and 37 females), age 14-35 with a complete ACL tear underwent primary repair of the ACL enhanced with a tissue-engineered scaffold (bridge-enhanced ACL repair) within 45 days of injury. International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome (KOOS) scores, as well as instrumented anteroposterior (AP) laxity through KT-1000 testing and functional outcome measures were obtained at time points up to 2 years postoperatively and compared between males and females using mixed model repeated measures analyses and chi square tests. Results: There was no significant sex difference on the postoperative IKDC Subjective Score at 3, 6, 12, or 24 months or any of the five KOOS scores at 12 and 24 months. Instrumented AP laxity testing demonstrated mean (standard deviation) side-to-side differences that were similar in the two sexes at 2 years; 1.7 (2.7) mm and 1.5 (3.7) mm in females and males, respectively, p = 0.72. At 6 months postoperatively, males had a larger deficit in hamstring strength on the operated leg (14.0% vs. 1.7%; p = 0.03) and a larger deficit in quadriceps strength on the operated leg (11.3% vs. 2.0%; p = 0.004); however, no sex difference was noted at 12 or 24 months. Females demonstrated superior single leg hop testing at 6 and 12 months ([91.3% vs. 78.1%, p = 0.001], [96.9% vs. 87.0%, p = 0.01] respectively). There were no significant sex differences on ipsilateral (males; 14.3% vs. females; 13.9%, p = 1.00) or contralateral (males; 3.6% vs. females; 2.8%, p = 1.00) ACL reinjury rates. Conclusions: Female subjects had better hamstring and quadriceps strength indices at 6 months than males as well as better hop test results at the 6 and 12-month time period. Despite this, there was no significant sex difference on patient-reported outcomes and objective AP laxity testing at time points up to 2 years postoperatively. Impact statement This is the first study comparing sex specific outcomes following the bridge-enhanced ACL repair technique (BEAR). The results of this study suggest that females have earlier recovery of both muscle strength and functional outcomes compared to their male counterparts. This is an important finding when considering future modifications to postoperative care and rehabilitation in females and males following this tissue-engineered BEAR technique.

Anatomical study of quadriceps tendon for anterior cruciate ligament reconstruction

Background

The quadriceps tendon is a promising alternative graft choice for anterior cruciate ligament (ACL) reconstruction. Morphology of the graft directly affects the biomechanical properties. However, a few studies are evaluating the anatomical structures of quadriceps tendon as a graft in Asian population.

Objective

To define the anatomical structures of quadriceps tendon as a graft for ACL reconstruction.

Methods

Forty-nine quadriceps tendons were dissected and analyzed. Measurements were also done including length, width, and thickness.

Results

The maximum length of superficial quadriceps tendon was 63.2 ± 12.5 mm (range 37.6–83.4). The maximum length of tendon at the deepest part was 57.2 ± 11.5 (range 30.9–83.4). The maximum length of quadriceps tendon was located at 61.4% ± 13% (range 31.8–83.6) from medial edge of the patella insertion (approximately 5 mm lateral from the center of quadriceps tendon insertion). The width of quadriceps tendon at patella insertion was 42.4 ± 3.8 mm (range 33.8–50.5). The thickness of quadriceps tendon at its maximum length on patella insertion was 6.9 ± 2.0 mm (range 1.5–9.5). Positive correlation between the height of cadaver and the maximum length of quadriceps tendon was noted.

Conclusions

The maximum length of quadriceps tendon was located 5 mm lateral from the center of quadriceps tendon insertion. Thus, we recommend marking midline of the quadriceps tendon insertion as a medial border of the harvested graft to get maximum length of the graft. Graft length measurement using superficial anatomy should be cautioned because graft shortening might occur.

No Difference in Outcome of Anterior Cruciate Ligament Reconstruction with "Bone-patellar Tendon-bone versus Semitendinosus-gracilis Graft with Preserved Insertion": A Randomized Clinical Trial

BACKGROUND

The type of graft for anterior cruciate ligament (ACL) reconstruction is still a topic of debate and there is still no clear consensus on the ideal graft for ACL reconstruction.

PURPOSE

This study was conducted to compare the outcome of ACL reconstruction surgery between hamstring tendon graft and bone-patellar tendon-bone (BPTB) graft.

MATERIALS AND METHODS

One hundred and sixty professional athletes were enrolled in the study. They were divided into two groups by computerized randomization. In Group I, ACL reconstruction was done using BPTB graft, and in Group II, ACL reconstruction was done using semitendinosus gracilis graft with preserved tibial insertion (STGPI). Postoperatively, patients were assessed for knee stability, Lysholm score, and WOMAC score.

RESULTS

Mean KT-1000 side-to-side difference at 1 year was 2.31 ± 1.68 mm in BPTB cohort and 2.52 ± 1.6 mm in STGPI cohort (P = 0.4); and at 2 years, it was 1.98 ± 1.62 mm in BPTB cohort and 2.23 ± 1.6 mm in STGPI cohort (P = 0.4). Mean Lysholm score at 2 years was 96.1 ± 5.81 in STGPI cohort and 97.3 ± 4.62 in BPTB cohort (P = 0.15). Mean WOMAC score at 2 years was 3.3 ± 2.76 in STGPI cohort and 2.84 ± 2.21 in BPTB cohort (P = 0.25). Graft rupture rate was 3.75%; 3 patients in each group had graft rupture. Kneeling pain was present in 15% (12/80) of patients with BPTB graft whereas none of the patients in STGPI cohort had kneeling pain.

CONCLUSION

There was no difference between two grafts in term of knee stability, visual analog scale score and functional outcome. However, hamstring tendon graft is associated with less donor site morbidity.

No Relationship Between Strength and Power Scores and Anterior Cruciate Ligament Return to Sport After Injury Scale 9 Months After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Psychological factors including self-reported readiness to return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR) measured with the Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI) scale have been shown to correlate with RTS. Physical deficits have been shown to exist in the later stages after ACLR rehabilitation. No previous studies have investigated the relationship between self-reported readiness to RTS and objective physical measures of power and strength.

PURPOSE

To investigate the relationship between ACL-RSI scores and measures of strength and power scores after ACLR.

STUDY DESIGN

Case control study; Level of evidence, 3.

METHODS

This study recruited 452 male athletes who had undergone primary ACLR. Each athlete completed the ACL-RSI questionnaire, isokinetic strength testing, and jump testing approximately 9 months after surgery.

RESULTS

ACL-RSI scores showed a trivial or weak correlation with strength and power measures at 9 months after surgery (r = 0.06-0.16). Similar results were found for the relationship between ACL-RSI scores and limb symmetry index for strength and power measures (r = 0.04-0.15). Comparing the strength and power measures of athletes with higher (≥90) ACL-RSI scores (n = 93) versus athletes with lower (≤75) ACL-RSI scores (n = 92) showed no significant differences except for isokinetic hamstring strength, but with a trivial effect size (P = .040; effect size = 0.15).

CONCLUSION

Self-reported readiness to RTS as measured by the ACL-RSI had little or no relationship with athletes' strength and power measures, and there was no meaningful difference in strength and power between athletes with higher and lower ACL-RSI scores at 9 months after ACLR. The findings suggest that psychological recovery and physical recovery after ACLR are different constructs, and strategies to measure and address each construct separately may be necessary to ensure successful RTS after ACLR.

Outcomes of isokinetic tests and functional assessment of anterior cruciate ligament reconstruction: Transtibial versus single anatomic femoral tunnel technique

Objective

The aim of the study was to compare the outcomes of the transtibial and anatomical femoral single tunnel surgical techniques in ACL reconstruction.

Methods

A total of 30 patients, with 16 patients (15 males and 1 female; mean age: 27.2 ± 7.04) with anatomical femoral single-tunnel technique (AFT) and 14 (12 males and 2 females; mean age: 29.4 ± 8.82) with transtibial technique (TT) were included into the study. All patients were evaluated with isokinetic tests at an angular velocity of 60°/s and 180°/s and the IKDC and Lysholm tests were performed preoperatively and in third, sixth, and 12th months postoperatively. The results were compared between the groups. The mean follow-up time was 17.1 ± 6.48 months.

Results

Postoperative third month changes in extension parameters of peak torque (AFT: −93.286, TT: −61.500), peak work (AFT: −77.071, TT: −47.500), peak torque ext/kg (AFT: −1.182, TT: −0.773), peak work ext/kg (AFT: −0.982, TT: −0.604), peak work (AFT: −55.143 TT: −33.063) at an angular velocity of 60°/s and postoperative third month change in extension parameter of peak power (AFT: −86.786 TT: −54.875) at an angular velocity of 180°/s were found to be better in the transtibial group (p < 0.05) and postoperative sixth month peak torque (AFT: 1.429, TT: −5.688) value at an angular velocity of 60°/s was found to be less in the anatomical femoral single-tunnel group (p < 0.05). The IKDC (AFT: 94.671, TT: 90.025) (p < 0.05) and Lysholm (AFT: 96.714, TT: 92.375) (p < 0.05) scores of the anatomical femoral single-tunnel group were better than the transtibial group regarding to the postoperative final follow-up. There are positive intermediate correlations between preoperative IKDC and Lysholm scores with preoperative and postoperative some isokinetic test ratio (r = 0.539; p = 0.031), and preoperative peak power extension (r = 0.541; p = 0.030) at the both angular velocity of 60°/s and 180°/s in the transtibial group. There was no significant difference between the two groups with regards to the Lachman, anterior drawer and pivot shift tests (p < 0.05).

Conclusion

There were differences in terms of isokinetic parameters in early outcomes but there was no statistical difference between isokinetic parameters at the end of 1st year between two groups. There were some correlations between IKDC and Lysholm scores with some isokinetic parameters.

Level of Evidence

Level III, Therapeutic Study.

Knee extensor and flexor strength before and after anterior cruciate ligament reconstruction in a large sample of patients: influence of graft type

OBJECTIVE

Hamstring and patellar tendon autografts are the most frequently-used graft types for anterior cruciate ligament (ACL) reconstruction, with no consensus on their respective effects on thigh muscle strength. The objective of this study was to re-examine isokinetic knee extensor and flexor strength before and after ACL reconstruction with patellar and hamstring tendon grafts using a single-center and a relatively large database, where surgical, rehabilitation and testing procedures were strictly standardized for all patients.

METHODS

A total of 464 patients with a unilateral ACL rupture underwent arthroscopic ACL reconstruction with either patellar or hamstring tendon grafts. Isokinetic concentric strength was evaluated prior to surgery and at 5- and 9-month postoperative follow-ups in different patient subgroups (n = 140, 464 and 215, respectively).

RESULTS

Knee extensor strength was lower in patients operated with the patellar tendon graft at the 5-month (p < 0.05) but not at the 9-month follow-up. Knee flexor strength was lower in patients operated with the hamstring tendon graft at both postoperative time points (p < 0.05). The prevalence of quadriceps weakness was high (66-91%) in both patient groups at both follow-ups.

CONCLUSION

Overall, postoperative recovery of thigh muscle function seems to be better with the patellar than with the hamstring tendon graft due to the fact that both, knee extensor and flexor strength, were more impaired after ACL reconstruction with the hamstring tendon autograft.

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.

No Difference in Outcome of Anterior Cruciate Ligament Reconstruction with "Bone-patellar Tendon-bone versus Semitendinosus-gracilis Graft with Preserved Insertion:" A Randomized Clinical Trial

BACKGROUND

The type of graft for anterior cruciate ligament (ACL) reconstruction is still a topic of debate and there is still no clear consensus on the ideal graft for ACL reconstruction.

PURPOSE

This study was conducted to compare the outcome of ACL reconstruction surgery between hamstring tendon graft and bone-patellar tendon-bone (BPTB) graft.

MATERIALS AND METHODS

One hundred and sixty professional athletes were enrolled in the study. They were divided into two groups by computerized randomization. In Group I, ACL reconstruction was done using BPTB graft, and in Group II, ACL reconstruction was done using semitendinosus gracilis graft with preserved tibial insertion (STGPI). Postoperatively, patients were assessed for knee stability, Lysholm score, and WOMAC score.

RESULTS

Mean KT-1000 side-to-side difference at 1 year was 2.31 ± 1.68 mm in BPTB cohort and 2.52 ± 1.6 mm in STGPI cohort (P = 0.4); and at 2 years, it was 1.98 ± 1.62 mm in BPTB cohort and 2.23 ± 1.6 mm in STGPI cohort (P = 0.4). Mean Lysholm score at 2 years was 96.1 ± 5.81 in STGPI cohort and 97.3 ± 4.62 in BPTB cohort (P = 0.15). Mean WOMAC score at 2 years was 3.3 ± 2.76 in STGPI cohort and 2.84 ± 2.21 in BPTB cohort (P = 0.25). Graft rupture rate was 3.75%; 3 patients in each group had graft rupture. Kneeling pain was present in 15% (12/80) of patients with BPTB graft whereas none of the patients in STGPI cohort had kneeling pain.

CONCLUSION

There was no difference between two grafts in term of knee stability, visual analog scale score and functional outcome. However, hamstring tendon graft is associated with less donor site morbidity.

Two-Plane Assessment of Knee Muscles Isometric and Isokinetic Torques After Anterior Cruciate Ligament Reconstruction

Background

We tested the hypothesis that, in patients participating in 17 weeks of postoperative physiotherapy after anterior cruciate ligament reconstruction (ACLR), maximal isometric torque (IT) and peak torque (PT) generated by the muscles affecting the operated knee joint in the sagittal and transverse planes are not restored. We also present the application of IT and PT measurements of the muscles affecting the knee joint in 2 planes of motion.

Material/Methods

IT and PT of the knee extensor and flexor muscles and the muscles internally rotating the shin were measured in 30 males who participated in postoperative physiotherapy for 17 weeks after ACLR (ACLR group) and 30 males with no injuries (control group).

Results

Significantly lower IT and PT values were noted in the operated knee extensors and flexors. The differences were also noted in the PT for the muscles internally rotating the shin and in the IT of those muscles in the position of 25° of internal rotation. Significantly lower relative IT and PT values were noted for studied muscle groups in comparison to the control group.

Conclusions

Seventeen weeks of postoperative physiotherapy after ACLR did not result in complete restoration of IT and PT of the muscles affecting the operated knee joint, suggesting that even after 17 weeks of physiotherapy following ACLR, athletes may not be ready to return to sports. The results demonstrate the usefulness of biplanar analysis of muscle strength under isometric and isokinetic conditions in the monitoring and assessment of physiotherapeutic procedures.

Criteria for return to running after anterior cruciate ligament reconstruction: a scoping review

Objective

To describe the criteria used to guide clinical decision-making regarding when a patient is ready to return to running (RTR) after ACL reconstruction.

Design

Scoping review.

Data sources

The MEDLINE (PubMed), EMBASE, Web of Science, PEDro, SPORTDiscus and Cochrane Library electronic databases. We also screened the reference lists of included studies and conducted forward citation tracking.

Eligibility criteria for selecting studies

Reported at least one criterion for permitting adult patients with primary ACL reconstruction to commence running postoperatively.

Results

201 studies fulfilled the inclusion criteria and reported 205 time-based criteria for RTR. The median time from when RTR was permitted was 12 postoperative weeks (IQR=3.3, range 5–39 weeks). Fewer than one in five studies used additional clinical, strength or performance-based criteria for decision-making regarding RTR. Aside from time, the most frequently reported criteria for RTR were: full knee range of motion or >95% of the non-injured knee plus no pain or pain <2 on visual analogue scale; isometric extensor limb symmetry index (LSI)>70% plus extensor and flexor LSI>70%; and hop test LSI>70%.

Conclusions

Fewer than one in five studies reported clinical, strength or performance-based criteria for RTR even though best evidence recommends performance-based criteria combined with time-based criteria to commence running activities following ACL reconstruction.

Hamstring Autograft for Foot and Ankle Applications

BACKGROUND

Hamstring tendon autografts may be used for foot and ankle surgeries, although reports on their effectiveness and morbidity in the foot and ankle literature are limited. We studied a cohort of patients who underwent hamstring harvest for foot and ankle applications, hypothesizing that morbidity to the knee would be limited.

METHODS

We studied a cohort of patients who underwent hamstring autograft for foot or ankle applications by a fellowship-trained sports and foot and ankle surgeon since 2011. Thirty-seven patients underwent isokinetic strength testing using a dynamometer an average of 38 months postoperatively. The average patient age was 45 ± 16 (range, 18-78) years, and 54% were women. Peak flexion and extension torque as well as flexion and extension torque at 30, 70, and 90 degrees of flexion were collected at 2 different testing speeds, 180 and 300 degrees/s. t tests were used for all comparisons.

RESULTS

At follow-up, 32 patients (86%) reported no pain at the harvest site; the remaining 5 patients reported mild to moderate symptoms. No patients were dissatisfied, and all would recommend the surgery to someone else. Flexion strength at higher degrees of flexion was significantly lower compared with extension strength as well as compared with flexion strength at lower degrees of flexion, when testing was performed at lower speed ( P < 0.05).

CONCLUSIONS

When used for foot and ankle surgery, hamstring autografts resulted in high patient satisfaction with minimal donor site morbidity. While knee flexion strength was decreased at higher degrees of flexion, this finding did not appear to be clinically significant.

LEVEL OF EVIDENCE

Level IV, case series.

Side-to-side asymmetries in landing mechanics from a drop vertical jump test are not related to asymmetries in knee joint laxity following anterior cruciate ligament reconstruction

PURPOSE

Asymmetries in knee joint biomechanics and increased knee joint laxity in patients following anterior cruciate ligament reconstruction (ACLR) are considered risk factors for re-tear or early onset of osteoarthritis. Nevertheless, the relationship between these factors has not been established. The aim of the study was to compare knee mechanics during landing from a bilateral drop vertical jump in patients following ACLR and control participants and to study the relationship between side-to-side asymmetries in landing mechanics and knee joint laxity.

METHODS

Seventeen patients following ACLR were evaluated and compared to 28 healthy controls. Knee sagittal and frontal plane kinematics and kinetics were evaluated using three-dimensional motion capture (200 Hz) and two synchronized force platforms (1000 Hz). Static anterior and internal rotation knee laxities were measured for both groups and legs using dedicated arthrometers. Group and leg differences were investigated using a mixed model analysis of variance. The relationship between side-to-side differences in sagittal knee power/energy absorption and knee joint laxities was evaluated using univariate linear regression.

RESULTS

A significant group-by-leg interaction (p = 0.010) was found for knee sagittal plane energy absorption, with patients having 25% lower values in their involved compared to their non-involved leg (1.22 ± 0.39 vs. 1.62 ± 0.40 J kg^-1). Furthermore, knee sagittal plane energy absorption was 18% lower at their involved leg compared to controls (p = 0.018). Concomitantly, patients demonstrated a 27% higher anterior laxity of the involved knee compared to the non-involved knee, with an average side-to-side difference of 1.2 mm (p < 0.001). Laxity of the involved knee was also 30% higher than that of controls (p < 0.001) (leg-by-group interaction: p = 0.002). No relationship was found between sagittal plane energy absorption and knee laxity.

CONCLUSIONS

Nine months following surgery, ACLR patients were shown to employ a knee unloading strategy of their involved leg during bilateral landing. However, this strategy was unrelated to their increased anterior knee laxity. Side-to-side asymmetries during simple bilateral landing tasks may put ACLR patients at increased risk of second ACL injury or early-onset osteoarthritis development. Detecting and correcting asymmetric landing strategies is highly relevant in the framework of personalized rehabilitation, which calls for complex biomechanical analyses to be applied in clinical routine.

LEVEL OF EVIDENCE

III.

Bone-Patellar Tendon-Bone Versus Hamstring Tendon Autografts for Primary Anterior Cruciate Ligament Reconstruction: A Systematic Review of Overlapping Meta-analyses

BACKGROUND

Previous meta-analyses have compared bone-patellar tendon-bone (BPTB) with hamstring tendon (HT) autografts for primary anterior cruciate ligament reconstruction (ACLR).

PURPOSE

To conduct a systematic review of overlapping meta-analyses comparing BPTB with HT autografts for ACLR to determine which meta-analyses provide the best available evidence.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review was performed by searching the PubMed and Cochrane Library databases. Search words included "anterior cruciate ligament" AND "patellar tendon" AND "hamstring tendon" AND "meta-analysis." Results were reviewed to determine study eligibility. Patient outcomes and postoperative complications were extracted from the included meta-analyses. Meta-analysis quality was assessed using the Oxman-Guyatt and Quality of Reporting of Meta-analyses (QUOROM) scores. The Jadad decision algorithm was then utilized to determine which meta-analyses provided the best level of evidence.

RESULTS

Sixteen meta-analyses containing an average of 1396 patients met the eligibility criteria. Most studies found BPTB autografts to provide superior stability but more postoperative complications, such as anterior knee pain and kneeling pain. Studies by Gabler et al (2016), Mohtadi et al (2011), and Xie et al (2015) received the highest Oxman-Guyatt and QUOROM scores, and therefore, these meta-analyses proved to provide the highest level of evidence. Additionally, Xie et al was selected as the highest-quality study in this systematic review based on the Jadad decision algorithm.

CONCLUSION

The current best evidence suggests that ACLR with BPTB autografts provides superior static knee stability and that there are fewer postoperative complications in ACLR with HT autografts.

Autogenous Hamstring-Bone Graft Preparation for Anterior Cruciate Ligament Reconstruction

Despite the popularity of anterior cruciate ligament (ACL) reconstruction procedures, the ideal graft for reconstruction remains a matter of controversy. The ideal graft for ACL reconstruction should have histologic and biomechanical characteristics similar to those of the native ACL; should be quickly and fully incorporated within the bony tunnels; should maintain its viscoelastic properties for a long time; should have minimal donor-site morbidity; should be of sufficient length and diameter; should have minimal adverse effects on the extensor mechanism; should have no risk of rejection or disease transmission; and should be cost-effective and readily available. Synthetic grafts are not widely accepted because of their dangerous complications. The main sources of grafts for ACL reconstruction are allografts and autografts. Each type of graft has its own relative advantages and disadvantages. Allografts are not available in every country, besides being expensive, and there are many concerns regarding disease transmission. Autografts, particularly bone-patellar tendon-bone (BPTB), and hamstring tendon grafts have been the standard for ACL reconstruction. The main advantage of autogenous BPTB grafts is the direct bone-to-bone healing in the tunnel, whereas the main disadvantages of such grafts are related to donor-site morbidity, anterior knee pain, and extensor mechanism dysfunction. The popularity of autogenous hamstring tendon grafts for ACL reconstruction is increasing, but there are still concerns regarding the slow soft tissue-to-bone healing, with delayed healing and incorporation of the graft. We describe a technique for ACL reconstruction with autogenous hamstring-bone graft, aiming to produce a type of graft that combines the main advantages of BPTB and hamstring grafts, with avoidance of the main disadvantages of these 2 most commonly used graft types in ACL reconstruction.

Hybrid Tibia Fixation of Soft Tissue Grafts in Anterior Cruciate Ligament Reconstruction: A Systematic Review

BACKGROUND

Optimal fixation of soft tissue grafts in anterior cruciate ligament (ACL) reconstruction remains a controversial topic, and tibial-sided fixation is frequently cited as the "weak point" of the femur-graft-tibia construct. Some studies have recommended the use of hybrid fixation (combining intratunnel aperture fixation and extracortical suspensory fixation) on the tibial side to increase the strength of the reconstructed ACL and decrease the risk of graft slippage and subsequent failure. However, no consensus has emerged on the necessity or suitability of this technique, relative to single modes of fixation.

PURPOSE

This study sought answers to the following questions: (1) Does hybrid fixation result in stronger, stiffer initial fixation of soft tissue grafts? (2) Does hybrid fixation reduce side-to-side laxity differences in clinical practice? (3) Does hybrid fixation increase complication rates when compared with a single mode of tibial fixation?

STUDY DESIGN

Systematic review.

METHODS

A systematic keyword search of PubMed, EMBASE, the Cochrane Library of Systematic Reviews, and the PROSPERO International Prospective Register of Systematic Reviews was performed. Candidate articles were included if they compared biomechanical or clinical characteristics of tibial-sided hybrid fixation (defined as a combination of aperture and suspensory fixation methods) with single-mode fixation of soft tissue grafts in ACL reconstruction.

RESULTS

A total of 21 studies (15 biomechanical, 6 clinical) met criteria for inclusion. Most biomechanical studies reported significantly increased strength and stiffness with hybrid fixation versus single modes of fixation. Among clinical studies, 66% reported significantly decreased anterior-posterior laxity when hybrid fixation methods were employed, with the remainder showing no difference.

CONCLUSION

Hybrid methods of tibial-sided graft fixation in ACL reconstruction result in stronger initial fixation and less side-to-side laxity after healing but do not change patient-reported outcomes at 1- to 3-year follow-up.

REGISTRATION

PROSPERO International Prospective Register of Systematic Reviews No. 42014015464.

Comparison of Graft Failure Rate Between Autografts Placed via an Anatomic Anterior Cruciate Ligament Reconstruction Technique: A Systematic Review, Meta-analysis, and Meta-regression

BACKGROUND

Recent data from the Danish anterior cruciate ligament (ACL) registry demonstrated increased reoperation rates for hamstring tendon autografts when an anatomic ACL reconstruction is performed. This is consistent with reports of greater time needed for hamstring tendon autografts to mature compared with other autografts.

PURPOSE

To review the literature comparing graft failure rate between patellar and hamstring tendon autografts placed anatomically and to determine if there are differences in return to preinjury activity levels between autografts.

STUDY DESIGN

Systematic review with meta-analysis and meta-regression.

METHODS

The PubMed, MEDLINE, SPORTDiscus, and CINAHL databases were used to identify studies published from January 1, 2000, through March 7, 2014. To compare postoperative outcomes between patellar tendon and hamstring tendon autografts, summary event rates for graft failure and return to preinjury activity level were calculated. A meta-analysis was performed to calculate a summary odds ratio (OR) for graft failure between autografts using the studies that directly compared the 2 autografts. Meta-regression analyses were performed to assess the influence of postoperative follow-up time on graft failure rate.

RESULTS

A total of 28 studies reported graft failures for patellar tendon (6 studies) and hamstring tendon (26 studies) autografts used with anatomic ACL reconstruction; 4 of the 28 were comparison studies. Graft failure rate was not significantly different between patellar tendon (7.0% [95% CI, 4.6%-10.5%]) and hamstring tendon autografts (3.9% [95% CI, 2.7%-5.6%]). The odds of graft failure were slightly higher for hamstring tendon autografts (OR, 1.21 [95% CI, 0.63-2.33]), but this difference was not significant (P = .57). The rate of patients returning to preinjury activity levels was not significantly different between patellar (n = 1 study; 58.1% [95% CI, 40.4%-73.9%]) and hamstring tendon autografts (n = 5 studies; 75.6% [95% CI, 43.7%-92.5%]). Overall graft failure rate was positively associated with postoperative follow-up time, but this effect was only significant with hamstring tendon autografts (P < .05).

CONCLUSION

Differences in graft failure rate between patellar tendon and hamstring tendon autografts were not significant. Although follow-up time was only found to have a significant influence on hamstring tendon graft failure rates, this was likely due to the smaller sample of studies assessing patellar tendon graft failures. Differences in return to preinjury activity levels could not be determined due to the lack of studies assessing that outcome. Both patellar and hamstring tendon autografts demonstrate a low risk of failure and moderately high return to activity level after anatomic ACL reconstruction.

The Importance of Patient Sex in the Outcomes of Anterior Cruciate Ligament Reconstructions: A Systematic Review and Meta-analysis

BACKGROUND

One of the well-studied epidemiological phenomena of anterior cruciate ligament (ACL) injuries is the 2- to 9-fold increase in the relative risk of ACL rupture in female athletes compared with male athletes. However, the influence of patient sex on the outcome after ACL reconstruction remains unclear, with some authors reporting inferior outcomes in females and others noting no significant difference.

PURPOSE

To provide a comprehensive systematic review and meta-analysis to examine the possible association between patient sex and the subjective and objective outcomes after ACL reconstruction.

METHODS

This study was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. All studies that reported clinical outcomes after ACL reconstruction in males and females independently were included in the review. A quantitative random-effects meta-analysis was performed to compare outcomes between sexes. For outcomes with considerable heterogeneity, meta-regression was used to identify potential moderators. Articles were evaluated qualitatively when quantitative data were not reported.

RESULTS

A total of 135 publications were included in the review. Females had inferior outcomes in instrumented laxity (standardized mean difference [SMD], 0.24; 95% CI, 0.11-0.37), revision rate (relative risk [RR], 1.15; 95% CI, 1.02-1.28), Lysholm score (SMD, -0.33; 95% CI, -0.55 to -0.11), Tegner activity scale (SMD, -0.37; 95% CI, -0.49 to -0.24), and incidence of not returning to sports (RR, 1.12; 95% CI, 1.04-1.21), all of which were statistically significant. Other outcomes were comparable between sexes, including anterior drawer test, Lachman test, pivot-shift test, timed single-legged hop test, single-legged hop test, quadriceps testing, hamstring testing, extension loss, flexion loss, development of cyclops lesion, and International Knee Documentation Committee (IKDC) knee examination score. Females and males were equally likely to develop anterior knee pain and osteoarthritis after ACL reconstruction. The graft rupture and graft failure rates did not differ significantly between sexes.

CONCLUSION

There were comparable or inferior results for females compared with males in all outcomes analyzed. No statistically significant sex difference was identified in most of the objective parameters. However, subjective and functional outcomes, including Lysholm score, Tegner activity scale, and ability to return to sports, have been shown to be poorer in females.

Functional results from reconstruction of the anterior cruciate ligament using the central third of the patellar ligament and flexor tendons

OBJECTIVES

To evaluate knee function in patients undergoing reconstruction of the anterior cruciate ligament (ACL) using the central third of the patellar ligament or the medial flexor tendons of the knee, i.e. quadruple ligaments from the semitendinosus and gracilis (ST-G), by means of the Knee Society Score (KSS) and the Lysholm scale.

METHODS

This was a randomized prospective longitudinal study on 40 patients who underwent arthroscopic ACL reconstruction between September 2013 and August 2014. They comprised 37 males and three females, with ages ranging from 16 to 52 years. The patients were numbered randomly from 1 to 40: the even numbers underwent surgical correction using the ST-G tendons and the odd numbers, using the patellar tendon. Functional evaluations were made using the KSS and Lysholm scale, applied in the evening before the surgical procedure and six months after the operation.

RESULTS

From the statistical analysis, it could be seen that the patients' functional capacity was significantly greater after the operation than before the operation. There was strong evidence that the two forms of therapy had similar results (p = >0.05), in all the comparisons.

CONCLUSIONS

The results from the ACL reconstructions were similar with regard to functional recovery of the knee and improvement of quality of life, independent of the type of graft. It was not possible to identify the best method of surgical treatment. The surgeon's clinical and technical experience and the patient are the factors that determine the choice of graft type for use in ACL surgery.

Biomechanical Outcomes of Bridge-enhanced Anterior Cruciate Ligament Repair Are Influenced by Sex in a Preclinical Model

BACKGROUND

Despite the well-established role of sex on the anterior cruciate ligament (ACL) injury risk, its effects on ACL surgical outcomes remain controversial. This is particularly critical when developing novel surgical techniques to treat the injury because there are limited data existing on how these procedures will respond in each sex. One such approach is bridge-enhanced ACL repair, in which primary suture repair of the ACL is augmented with a bioactive scaffold saturated with autologous blood. It has shown comparable biomechanical outcomes to ACL reconstruction in preclinical models.

QUESTIONS/PURPOSES

We asked (1) whether sex affects the biomechanical outcomes of bridge-enhanced ACL repair; and (2) if suture type (absorbable or nonabsorbable), used to repair the torn ACL, can minimize the potential sex discrepancies in outcomes after 15 weeks of healing in a large animal preclinical model.

METHODS

Seventeen (eight males, nine females) Yorkshire pigs (Parson's Farms, Hadley, MA, USA) underwent bilateral ACL transection and received bridge-enhanced ACL repair with an absorbable suture (n=17) on one side and with a nonabsorbable suture (n=17) on the other side. The leg receiving the absorbable suture was randomized within each animal. ACL structural properties and AP knee laxity for each knee were measured after 15 weeks of healing. Mixed linear models were used to compare the biomechanical outcomes between sexes and suture groups.

RESULTS

When treated with absorbable suture, females had a lower ACL linear stiffness (females, 11 N/mm [range, 8-42]; males, 31 N/mm [range, 12-56]; difference, 20 N/mm [95% confidence interval {CI}, 4-36]; p=0.032), ACL yield (females, 121 N [range, 56-316]; males, 224 N [range, 55-538]; difference, 103 N [95% CI, 6-200]; p=0.078), and maximum load (females, 128 N [range, 63-332]; males, 241 N [range, 82-538]; difference, 114 N [95% CI, 15-212]; p=0.052) than males after 15 weeks of healing. Female knees treated with absorbable suture had a lower linear stiffness (absorbable, 11 N/mm [range, 8-42]; nonabsorbable, 25 N/mm [range, 8-64]; difference, 14 [95% CI, 2-26] N; p=0.054), ACL yield (absorbable, 121 N [range, 56-316]; nonabsorbable, 230 N [range, 149-573]; difference, 109 N [95% CI, 56-162]; p=0.002), and maximum load (absorbable, 128 N [range, 63-332]; nonabsorbable, 235 N [range, 151-593]; difference, 107 N [95% CI, 51-163]; p=0.002) along with greater AP knee laxity at 30° (absorbable, 9 mm [range, 5-12]; nonabsorbable, 7 mm [range, 2-13]; difference, 2 mm [95% CI, 1-4]; p=0.034) than females treated with nonabsorbable suture. When repaired using nonabsorbable suture, the biomechanical outcomes were similar between female and male knees (p>0.10).

CONCLUSIONS

Females had significantly worse biomechanical outcomes than males when the repairs were performed using absorbable sutures. However, the use of nonabsorbable sutures ameliorated these differences between males and females.

CLINICAL RELEVANCE

The current findings highlight the critical role of sex on the biomechanical outcomes of bridge-enhanced ACL repair in a relevant large animal model. Better understanding of the mechanisms responsible for these observations using preclinical models and concomitant clinical studies in human patients may allow for additional development of sex-specific surgical and rehabilitative strategies with potentially improved outcomes in women.

Sex Influences the Biomechanical Outcomes of Anterior Cruciate Ligament Reconstruction in a Preclinical Large Animal Model

BACKGROUND

The risk of anterior cruciate ligament (ACL) injury is 2 to 10 times greater in women than men. While the effect of sex on injury risk is well established, its effects on surgical outcomes remain controversial.

PURPOSE/HYPOTHESIS

To investigate whether the biomechanical outcomes of ACL reconstruction are affected by sex using an established porcine model that displays similar sex-specific differences in knee anatomy and ligament structural properties to humans. The hypothesis was that there will be sex differences in ACL reconstruction outcomes with regard to the graft structural properties, knee laxity, and cartilage damage.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 41 adolescent Yucatan minipigs (23 male, 18 female) underwent unilateral ACL transection and ACL reconstruction using sex-matched bone-patellar tendon-bone allografts (with or without additional bioenhancement). Graft biomechanical and histological properties, knee laxity, and cartilage damage were assessed after 15 weeks. A 2-factor analysis of variance was used to investigate the effect of sex on all the measured outcomes after adjusting for the treatment effect.

RESULTS

After 15 weeks of healing, female pigs had a significantly lower mean normalized graft yield load (by 18.5% ± 7.7%; P = .023) and linear stiffness (by 11.9% ± 5.6%; P = .043) compared with male pigs. Female pigs had significantly greater side-to-side differences in anteroposterior knee laxity at 30° (by 1.4 ± 0.6 mm; P = .028) and 90° (by 1.8 ± 0.8 mm; P = .032). Female pigs had a lower graft vascular density (by 0.8 ± 0.3 [analog scoring]; P = .021) with similar cellular and collagen-based histologic scores in both sexes (P > .6). Female pigs also had a significantly larger area of cartilage damage (by 43.3 ± 14.8 mm(2); P = .014) after conventional ACL reconstruction compared with their male counterparts.

CONCLUSION

Female pigs had significantly worse outcomes (ie, graft structural properties, knee laxity, and cartilage damage) compared with male pigs in this translational model after 15 weeks of healing.

CLINICAL RELEVANCE

These data suggest that further optimization of ACL injury treatments may be needed to accommodate each sex instead of using a "one fits all" approach to improve surgical outcomes, decrease incidence of reinjury, and decrease posttraumatic osteoarthritis risk after ACL reconstruction.

Deficits in Quadriceps Strength and Patient-Oriented Outcomes at Return to Activity After ACL Reconstruction: A Review of the Current Literature

Context:

Side-to-side quadriceps strength deficits are linked to hazardous lower extremity mechanics and reduced function at a time when individuals are returned to activity after anterior cruciate ligament (ACL) reconstruction. As a result, generalized criteria have emerged in the literature, wherein researchers are recommending that patients be cleared for participation once side-to-side differences in strength are ≤10% of the noninjured limb. Similar recommendations exist for patient-oriented outcomes (ie, self-reported function and hop tests), where deficits of ≤10% are considered ideal at return to activity. It is unclear how many studies actually achieve these clinically recommended results.

Evidence Acquisition:

Articles that reported quadriceps strength deficits as compared to the contralateral limb were collected from peer-reviewed sources available on Medline and Web of Science databases (1990 through August 2014). Search terms included the following: anterior cruciate ligament OR ACL AND muscle weakness, anterior cruciate ligament OR ACL AND strength; return-to-activity AND strength; anterior cruciate ligament OR ACL AND quadriceps.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Average side-to-side strength deficits at 6 months postreconstruction were 23% ± 8% (range, 3%-40%), while the average at 12 months postsurgery was found to be 14% ± 6% (range, 3%-28%). The average deficits in self-reported function at 6 months (mean, 14% ± 5%) and 12 months postsurgery (mean, 13% ± 6%) were also found to be >10%. Performance on hop tests was found to be less than optimal at 6 months postsurgery (mean, 11% ± 7%), but improved at 12 months postsurgery (mean, 1.3% ± 2%).

Conclusion:

This review provides an up-to-date account of the typical deficits in strength and patient-oriented outcomes that exist when formalized physical therapy concludes after ACL reconstruction. Based on the studies included, it seems pertinent that researchers and clinicians continue to investigate interventions capable of improving the recovery of quadriceps strength as well as patient-oriented outcomes as the majority of studies report levels that are well below clinical recommendations.

Factors associated with excellent 6-month functional and isokinetic test results following ACL reconstruction

PURPOSE

To identify patient concomitant injury and surgical characteristics associated with 6-month excellent functional and isokinetic testing results following anterior cruciate ligament (ACL) reconstruction.

METHODS

Patients that underwent ACL reconstruction by a single surgeon had isokinetic and functional testing performed with excellent 6-month outcome defined as greater than 85 % in isokinetic strength and 90 % in functional tests (excellent 6-month group vs. delayed 6-month group). Patient concomitant injury and surgical factors were then analysed in univariate and multivariate statistical models to assess which characteristics predicted the excellent 6-month group.

RESULTS

The 224 patients included 93 males and 131 females, with median age of 22 (range 12-59) years, body mass index (BMI) of 25.4 (range 17-44), and median Tegner activity score of 6 (range 2-10). Fifty-two patients (23 %) were included in the excellent 6-month group, while 172 patients (77 %) were in the delayed 6-month group. In univariate analysis, favourable factors with the excellent 6-month outcome group were younger age (24 vs. 27; p = 0.01), lower BMI (24.5 vs. 26.2; p = 0.03), and minimal articular cartilage damage (71 vs. 56 %; p = 0.048). In multivariate analysis, a negative effect was observed for patients older than 30 years that had ACL reconstruction with autograft (p = 0.0004).

CONCLUSION

Factors significantly associated with excellent 6-month functional and isokinetic test results following ACL reconstruction included younger age, lower BMI, and minimal cartilage degeneration. The use of allograft was associated with improved functional and strength testing after ACL reconstruction in patients over 30 years of age.

LEVEL OF EVIDENCE

Prognostic/therapeutic study, Level III.

Return to play following ACL reconstruction: a systematic review about strength deficits

PURPOSE

There is a lack of consensus regarding appropriate criteria attesting patients' unrestricted sports activities after ACL reconstruction. Purpose of this study was to perform a systematic review about strength deficits to find out if a strength test might be a return to play criterion.

DATA SOURCE

Pubmed central, Google Scholar.

STUDY ELIGIBILITY CRITERIA

English language articles.

INTERVENTIONS

Strength tests after ACL reconstruction with autologous tendon grafts.

METHODS

A systematic search for articles about muscle strength after ACL reconstruction was performed.

RESULTS

Forty-five articles could be identified. All articles identified reported strength deficits after ACL reconstruction in comparison to control subjects. Some of these deficits persisted up to 5 years after surgery. Knee flexor strength is more impaired after ACL reconstruction with hamstring grafts and quadriceps strength after BPTB ACL reconstruction.

CONCLUSION

Strength deficits of hip, knee and ankle muscles are reported after ACL reconstruction. Muscular strength test may be an important tool to determine if an athlete can return to competitive sports after ACL reconstruction.

The effect of posterior tibial slope on knee flexion in posterior-stabilized total knee arthroplasty

PURPOSE

To evaluate and quantify the effect of the tibial slope on the postoperative maximal knee flexion and stability in the posterior-stabilized total knee arthroplasty (TKA).

METHODS

Fifty-six patients (65 knees) who had undergone TKA with the posterior-stabilized prostheses were divided into the following 3 groups according to the measured tibial slopes: Group 1: ≤4°, Group 2: 4°-7° and Group 3: >7°. The preoperative range of the motion, the change in the posterior condylar offset, the elevation of the joint line, the postoperative tibiofemoral angle and the preoperative and postoperative Hospital for Special Surgery (HSS) scores were recorded. The tibial anteroposterior translation was measured using the Kneelax 3 Arthrometer at both the 30° and the 90° flexion angles.

RESULTS

The mean values of the postoperative maximal knee flexion were 101° (SD 5), 106° (SD 5) and 113° (SD 9) in Groups 1, 2 and 3, respectively. A significant difference was found in the postoperative maximal flexion between the 3 groups (P < 0.001). However, no significant differences were found between the 3 groups in the postoperative HSS scores, the changes in the posterior condylar offset, the elevation of the joint line or the tibial anteroposterior translation at either the 30° or the 90° flexion angles. A 1° increase in the tibial slope resulted in a 1.8° flexion increment (r = 1.8, R (2) = 0.463, P < 0.001).

CONCLUSION

An increase in the posterior tibial slope can significantly increase the postoperative maximal knee flexion. The tibial slope with an appropriate flexion and extension gap balance during the operation does not affect the joint stability.

Effect of prehabilitation on the outcome of anterior cruciate ligament reconstruction

BACKGROUND

Prehabilitation is defined as preparing an individual to withstand a stressful event through enhancement of functional capacity.

HYPOTHESIS

We hypothesized that a preoperative exercise program would enhance postoperative outcomes after anterior cruciate ligament reconstruction (ACLR).

STUDY DESIGN

Randomized controlled clinical trial; Level of evidence, 1.

METHODS

Twenty volunteers awaiting ACLR were randomly assigned to a control or exercise intervention group. The exercise group completed a 6-week gym- and home-based exercise program. Assessments include single-legged hop test; quadriceps and hamstring peak torque and magnetic resonance imaging cross-sectional area (CSA); Modified Cincinnati Knee Rating System score; and muscle biopsy of the vastus lateralis muscle completed at baseline, preoperatively, and 12 weeks postoperatively. Myosin heavy chain (MHC) isoforms protein and messenger RNA (mRNA) expression were determined with SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) and RT-PCR (real-time polymerase chain reaction), respectively; IGF-1 (insulin-like growth factor 1), MuRF-1 (muscle RING-finger protein-1), and MAFbx (muscle atrophy f-box) mRNA expression were determined with quantitative RT-PCR.

RESULTS

Following 6 weeks of exercise intervention, the single-legged hop test results improved significantly in the exercise-injured limb compared with baseline (P = .001). Quadriceps peak torque in the injured limb improved with similar gains in CSA compared with baseline (P = .001). However, this was not significantly increased compared with the control group. Quadriceps and vastus medialis CSA were also larger in the exercise group than in controls (P = .0024 and P = .015, respectively). The modified Cincinnati score was better in the exercise-injured limb compared with baseline. At 12 weeks postoperatively, the rate of decline in the single-legged hop test was reduced in the exercise group compared with controls (P = .001). Similar trends were not seen for quadriceps peak torque and CSA. The vastus medialis CSA had regressed to similar levels as the control group (P = .008). The modified Cincinnati score continued to increase in the exercise group compared with controls (P = .004). The expression of the hypertrophic IGF-1 gene was significantly increased after the exercise intervention (P = .028), with a decrease back to baseline 12 weeks postoperatively (P = .012). Atrophic MuRF-1 gene expression was decreased after intervention compared with baseline (P = .05) but increased again at 12 weeks postoperatively (P = .03). The MAFbx levels did not change significantly in either group and within each time point. On the mRNA level, there was a shift from MHC-IIx isoform to MHC-IIa after exercise, with significant changes compared with control preoperatively (P = .028). Protein testing was able to reproduce this increase for MHC-IIa isoform expression only.

CONCLUSION

The 6-week progressive prehabilitation program for subjects undergoing ACLR led to improved knee function based on the single-legged hop test and self-reported assessment using the modified Cincinnati score. These effects were sustained at 12 weeks postoperatively. This study supports prehabilitation as a consideration for patients awaiting ACLR; however, further studies are warranted.

Anterior cruciate ligament graft choices

CONTEXT

Reconstruction of the anterior cruciate ligament (ACL) is a common surgical procedure; however, there is no consensus to what the best graft option is to replace the injured ACL. The main options available consist of allografts and autografts, which include patellar tendon, hamstring tendon, and quadriceps tendon autografts.

EVIDENCE ACQUISITION

The PubMed database was searched in August 2010 for English-language articles pertaining to ACL grafts.

RESULTS

Postoperative outcome variables were analyzed to determine similarities and differences among the different graft options. These variables include stability, strength, function, return to sports, patient satisfaction, complications, and cost.

CONCLUSIONS

Both allografts and the 3 main options for autografts can provide excellent results in ACL reconstruction and lead to a high percentage of satisfied patients. However, differences exist among the graft choices. Both the similarities and the differences are important to discuss with a patient who will be undergoing ACL reconstruction so that he or she has the best information available when making a choice of graft.

A between sex comparison of anterior-posterior knee laxity after anterior cruciate ligament reconstruction with patellar tendon or hamstrings autograft: a systematic review

Anterior-posterior (AP) knee laxity after anterior cruciate ligament (ACL) reconstruction may differ between sexes for different graft types. Females may experience an increase in AP knee laxity following an ACL reconstruction with a hamstrings graft, which is not seen in males with a hamstrings graft or in males or females with a bone-patellar tendon-bone (BTB) graft. The hypothesis of this review is sex differences in AP knee laxity and this will be identified in patients who undergo an ACL reconstruction with a hamstrings graft, while no sex differences will be observed in patients who have an ACL reconstruction with a BTB graft. A systematic search was performed in PubMed, CINAHL and SPORTDiscus. Inclusion criteria were articles published in the English language that studied human subjects who underwent an ACL reconstruction with a BTB or hamstrings autograft, and the presence of a sex comparison on outcome measures including side-to-side difference in AP knee laxity. Methodological quality was assessed using a Modified Coleman Methodology Score. Eleven cohort studies met the inclusion criteria. Six investigated sex differences in both hamstrings and BTB grafts. Three only investigated BTB grafts and two only investigated hamstrings grafts. These studies consistently reported increases in AP knee laxity in females after an ACL reconstruction with a hamstrings graft that was not observed in the other cohorts. This systematic review indicates that female patients have greater AP knee laxity following an ACL reconstruction with a hamstrings autograft compared with males with a similar procedure, and both females and males following an ACL reconstruction with a BTB autograft. These results are derived from lower level evidence, as no randomized control trials have attempted to answer this question. Future studies need to rigorously address this clinical question to confirm the results currently in the literature.

Isokinetic muscle strength and knee function associated with double femoral pin fixation and fixation with interference screw in anterior cruciate ligament reconstruction

PURPOSE

Intensive scheduling in sports requires athletes to resume physical activity shortly after injury. The purpose of this study was to investigate early isokinetic muscle strength and knee function on bone-patellar tendon-bone (BPTB) ACL reconstruction with double femoral pin fixation or interference screw technique.

METHODS

A prospective study was conducted from 2008 to 2009, with 48 athletes who received femoral BPTB fixation with interference screw (n = 26) or double pin (n = 22). Clinical (IKDC objective score and hop test) and isokinetic muscle strength (peak torque (PT), PT/body weight and flexion/extension rate (F/E) in 60 and 240°/s) were analyzed at 6 months of follow-up.

RESULTS

Analysis at baseline showed no differences between groups before surgery related to age, gender, associated injury, Tegner or Lysholm score; thus showing that groups were similar. During follow-up, however, there were significant differences between the two groups in some of the isokinetic muscle strength: PT/BW 60°/s (Double Pin = 200% ± 13% vs. Interference Screw = 253% ± 16%*, *P = 0.01); F/E 60°/s (Double Pin = 89% ± 29%* vs. Interference Screw = 74% ± 12%, *P = 0.04). No statistical differences between groups were observed on IKDC objective score, hop test and complications.

CONCLUSION

The significant muscle strength outcome of the interference screw group found in this study gives initial evidence that this fixation technique is useful for athletes that may need accelerated rehabilitation. Early return to sports ability signaled by isokinetic muscle strength is of clinical relevance as it is one of the main goals for athletes' rehabilitation.

Effects of additional gracilis tendon harvest on muscle torque, motor coordination, and knee laxity in ACL reconstruction

PURPOSE

To evaluate muscle torque, lower extremity coordination, and knee laxity after ACL reconstruction comparing patients operated on with semitendinosus graft (ST) and patients with combined semitendinosus and gracilis (STGR) grafts.

METHODS

Forty-six subjects who underwent ST (n = 23) or STGR harvest (n = 23) ACL reconstruction participated in this study. Quadriceps and hamstring torque were recorded using an isokinetic dynamometer. The anterior tibial translation was measured using the Kneelax 3 Arthrometer. The eccentric and concentric motor coordination was tested by multi-joint lower-limb tracking-trajectory test. All measurements were taken 12 months after surgery. Side-to-side differences were determined for all subjects.

RESULTS

Side-to-side differences in extensor peak torque at 180°/s and 60°/s did not differ between semitendinosus (ST) and semitendinosus + gracilis (STGR) groups (n.s.). However, side-to-side differences in flexor peak torque were significantly higher at 60°/s for the STGR group than the ST group (P = 0.002). Side-to-side differences in eccentric and concentric parts of tracking-trajectory test and anterior tibial translation did not differ between the STGR and the ST groups (n.s.).

CONCLUSION

The outcomes of this study suggested that additional harvest of gracilis did not influence lower extremity motor control, quadriceps muscle torque, and anterior tibial translation; however, it affected knee flexion isokinetic torque negatively at low angular velocity. This finding could be important for functional activity or sports with high demands on hamstring muscle strength. It is recommended that gracilis muscle should be preserved as possible during ACL reconstruction.

LEVEL OF EVIDENCE

Prospective comparative study, Level II.

The influence of graft choice on isokinetic muscle strength 4-24 months after anterior cruciate ligament reconstruction

PURPOSE

Regaining adequate strength of the quadriceps and hamstrings after anterior cruciate ligament (ACL) reconstruction is important for maximizing functional performance. However, the outcome of muscle strength after either BPTB or hamstrings autograft is unclear given the plethora of published studies that report post-operative muscle strength. The purpose of this study was to systematically compare the muscle strength of patients who have undergone ACL reconstruction using either Bone Patellar Tendon Bone (BPTB) or Hamstrings (HST) autograft.

METHODS

The databases of MEDLINE, Cinahal and EMBASE were systematically searched for articles that report muscle strength outcome following ACL reconstruction. The quality of the studies was evaluated and a meta-analysis of the muscle strength outcomes was conducted on reported data.

RESULTS

Fourteen studies were included in this systematic review: eight Randomized Control Studies (RCT) and six non-Randomized Control Studies (non-RCT). A meta-analysis was performed involving eight of the included studies (4 RCTs & 3 non-RCTs). At 60°/s and 180°/s, patients with BPTB graft showed a greater deficit in extensor muscle strength and lower deficit in flexor muscle strength compared with patients with HST.

CONCLUSION

This systematic review of Level III evidence showed that isokinetic muscle strength deficits following ACL reconstruction are associated with the location of the donor site. These deficits appear to be unresolved up to 2 years after ACL reconstruction.

LEVEL OF EVIDENCE

III.

The reliability of portable fixed dynamometry during hip and knee strength assessments

CONTEXT

Insufficient lower extremity strength may be a risk factor for lower extremity injuries such as noncontact anterior cruciate ligament tears. Therefore, clinicians need reliable instruments to assess strength deficiencies.

OBJECTIVE

To assess the intrarater, interrater, intrasession, and intersession reliability of a portable fixed dynamometer in measuring the strength of the hip and knee musculature.

DESIGN

Crossover study.

SETTING

Sports medicine research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Three raters (A, B, C) participated in this 2-phase study. Raters A and B tested 11 healthy college graduate students (2 men, 9 women) in phase 1. Raters A and C tested 26 healthy college undergraduate students (7 men, 19 women) in phase 2.

MAIN OUTCOME MEASURE(S)

The dependent variables for the study were hip adductor, hip abductor, hip flexor, hip extensor, hip internal rotator, hip external rotator, knee flexor, and knee extensor peak force.

RESULTS

The phase 1 intrasession intraclass correlation coefficients for sessions 1, 2, and 3 ranged from 0.88 to 0.99 (SEM = 0.08-3.02 N), 0.85 to 0.99 (SEM = 0.26-3.88 N), and 0.92 to 0.96 (SEM = 0.52-2.76 N), respectively. Intraclass correlation coefficients ranged from 0.57 to 0.95 (SEM = 1.72-13.15 N) for phase 1 intersession values, 0.70 to 0.94 (SEM = 1.42-9.20 N) for phase 2 intrarater reliability values, and 0.69 to 0.88 (SEM = 1.20-8.50 N) for phase 2 interrater values.

CONCLUSIONS

The portable fixed dynamometer showed good to high intrasession and intersession reliability values for hip and knee strength. Intrarater and interrater reliability were fair to high, except for hip internal rotation, which showed poor reliability.

Graft selection for anterior cruciate ligament reconstruction: a level I systematic review comparing failure rates and functional outcomes

Tear of the anterior cruciate ligament (ACL) is the most common ligamentous injury of the knee. Reconstructing this ligament is often required to restore functional stability of the knee. Many graft options are available for ACL reconstruction, including different autograft and allograft tissues. Autografts include bone-patellar tendon-bone composites (PT), combined semitendinosus and gracilis hamstring tendons (HT), and quadriceps tendon. Allograft options include the same types of tendons harvested from donors, in addition to Achilles and tibialis tendons. Tissue-engineered anterior cruciate grafts are not yet available for clinical use, but may become a feasible alternative in the future. The purpose of this systematic review is to assess whether one of the popular grafts (PT and HT) is preferable for reconstructing the ACL. For this objective, the authors selected only true level I studies that compared these graft choices in functional clinical outcomes, failure rates, and other objective parameters following reconstruction of the ACL. In addition, this review discusses mechanical considerations related to different allograft tissues.

Knee flexor strength after ACL reconstruction: comparison between hamstring autograft, tibialis anterior allograft, and non-injured controls

Hamstring muscle group dysfunction following anterior cruciate ligament reconstruction (ACL) using a semitendinosus-gracilis autograft is a growing concern. This study compared the mean peak isometric knee flexor torque of the following three groups: subjects 2 years following ACL reconstruction using semitendinosus-gracilis autografts (Group 1), subjects 2 years following ACL reconstruction using tibialis anterior allografts (Group 2), and a non-injured, activity-level-matched control group (Group 3). We hypothesized that Group 1 would have greater mean involved lower extremity peak isometric knee flexor torque deficits than the other groups. Handheld dynamometry with subjects in prone and the test knee at 90 degrees flexion was used to determine bilateral peak isometric knee flexor torque. Group 1 (86.4 +/- 11) and Group 2 (80.5 +/- 13) had similar 2000 IKDC Subjective Knee Evaluation Form scores (P = NS). Group 1 had a mean involved lower extremity peak isometric knee flexor torque deficit of -17.0 +/- 14 Nm. Group 2 had a mean involved lower extremity peak isometric knee flexor torque deficit of -0.8 +/- 9 Nm. Group 3 (control) had a mean left and right lower extremity peak isometric knee flexor torque difference of -0.7 +/- 14 Nm. Group 1 had decreased involved lower extremity peak isometric knee flexor torque compared to Groups 2 and 3 (two-way ANOVA; group x side interaction P < 0.05, Tukey HSD = 0.008). Long-term knee flexor strength deficits exist following hamstring autograft use for ACL reconstruction that does not occur when a tibialis anterior allograft is used. Early identification of impaired knee flexor strength among this group and modified rehabilitation may reduce these deficits. Adding quantitative biomechanical testing of sprinting and sudden directional change movements to the standard physical therapy evaluation will better elucidate the clinical and functional significance of the observed knee flexor strength impairments and aid in determining sport specific activity training readiness.

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.

Functional outcomes and health-related quality of life after robot-assisted anterior cruciate ligament reconstruction with patellar tendon grafts

During a short period of time, surgical robots had been propagated for automated tunnel placement in anterior cruciate ligament (ACL) reconstruction. Clinical outcome data are currently unavailable. Between 2000 and 2003, 152 patients underwent ACL replacement with the assistance of the Computer Assisted Surgical Planning and Robotics system (CASPAR, OrtoMaquet, Germany) at our hospital. After minimal invasive pin placement in both the tibia and femur, computed tomography was used to register anatomical landmarks and to plan graft tunnel alignment. The robot was used to drill tibial and femoral tunnels in an outside-in fashion according to pre-operative planning. There was one procedure-specific Serious Adverse Event (i.e., an intraoperative transection of the posterior cruciate ligament). After IRB approval, all patients were invited for a follow-up examination. Data from 100 patients (35 women, 65 men, mean age 35 [SD 11] years, median follow-up 61 [range 42-77] months) form the basis of this report. Side-to-side differences in anterior laxity were measured with the KT-1000 arthrometer. Patient-centered outcomes included the Lysholm-Score, the lower extremity functional scale (LEFS), and the Short Form 36 (SF36). The mean KT-1000 side-to-side difference was 0.89 [95% confidence interval (CI) 0.52-1.26] mm. Eight and five patients had a positive Lachman and pivot shift test, respectively. The Lysholm-Score averaged 86 (95% CI 83-89) points. Excellent, good, fair, and poor outcomes were reported by 38, 32, 20, and 10 patients. The LEFS averaged 85 (95% CI 82-88) points. The mean SF36 Physical Component Score was 48.4 (95% CI 46.5-50.3), indicating residual deficits compared to the population norm. All tibial graft tunnels did not cross the Blumensaat line, but were placed slightly anterior to the optimal center of 42% reported in previous studies. Compared to literature data, robot-assisted ACL reconstruction with BTB grafts may lead to higher knee stability, but poorer functional outcomes. The immense additional efforts with the procedure did not pay off in a benefit to patients.

FUNCTIONAL PERFORMANCE AND KNEE LAXITY IN NORMAL INDIVIDUALS AND IN INDIVIDUALS SUBMITTED TO ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

The aim of this study was to analyze the correlation between deficits in the isokinetic peak torque of the knee extensors and flexors with hop tests, postoperative knee laxity and functional scores in normal and ACL- reconstructed subjects with patellar tendon and hamstring tendon autografts. Methods: Sixty male subjects were enrolled and subdivided into three groups: Twenty subjects without knee injuries (GC group) and two groups of 20 subjects submitted to ACL reconstruction with patellar tendon (GTP group) and hamstrings autograft (GTF group). Results: The results showed significant correlation between knee extensors peak torque and performance in the hop tests for GTF and GC groups. There are no significantly correlations between post op knee laxity and Lysholm score compared with the hop tests and peak torque deficits. Concerning the differences between groups, the GTP group showed greater peak torque deficits in knee extensors, worst Lysholm scores and higher percentage of individuals with lower limb symmetry index (ISM) < 90% in both hop tests when compared to the other two groups. Conclusion: It is not recommendable to use only one measurement instrument for the functional evaluation of ACL-reconstructed patients, because significant correlation between peak torque, subject's functional score, knee laxity and hop tests were not observed in all groups.