The long-term clinical and radiological outcomes in patients who suffer recurrent injuries to the anterior cruciate ligament after reconstruction

Correlation between higher lateral tibial slope and inferior long term subjective outcomes following single bundle anterior cruciate ligament reconstruction

BACKGROUND

The impact of anatomical factors, such as the lateral tibial slope (LTS), on outcomes following anterior cruciate ligament (ACL) reconstruction is an area of growing interest. This study was led by the observation that patients with a higher LTS may have different recovery trajectories.

HYPOTHESIS/PURPOSE

The purpose of this study was to investigate the correlation between a higher LTS and long term subjective outcomes following single-bundle ACL reconstruction.

STUDY DESIGN

This study was designed as a retrospective cohort study.

METHODS

The study comprised 138 patients who underwent single-bundle ACL reconstruction. The LTS was measured on preoperative radiographs. Patient-reported outcome measures (PROMs) were collected, which included the Lysholm Knee Score, UCLA Activity Score, IKDC Score, and Tegner Activity Score, over a mean follow-up duration of 137 months.

RESULTS

A significant negative correlation was found between LTS and all measured PROMs (p < 0.001). The established cut-off value of LTS distinguishing between "Good" and "Fair" Lysholm scores was 8.35 degrees. Female patients have statistically significant higher LTS and lower PROMs scores than male. Patients with LTS greater than or equal to 8.35 had significantly lower PROMs, indicative of poorer functional and subjective outcomes.

CONCLUSION

Our findings suggest that a higher LTS is associated with inferior subjective outcomes following single-bundle ACL reconstruction in long term. The LTS cut-off value of 8.35 degrees could potentially be used as a reference in preoperative planning and patient counseling.

CLINICAL RELEVANCE

Understanding the relationship between LTS and ACL reconstruction outcomes could inform surgical planning and postoperative management. These findings highlight the need to consider anatomical variances, such as LTS, when assessing patient-specific risks and recovery expectations, contributing to the advancement of personalized care in sports medicine.

Enhanced reliability and time efficiency of deep learning-based posterior tibial slope measurement over manual techniques

PURPOSE

Multifaceted factors contribute to inferior outcomes following anterior cruciate ligament (ACL) reconstruction surgery. A particular focus is placed on the posterior tibial slope (PTS). This study introduces the integration of machine learning and artificial intelligence (AI) for efficient measurements of tibial slopes on magnetic resonance imaging images as a promising solution. This advancement aims to enhance risk stratification, diagnostic insights, intervention prognosis and surgical planning for ACL injuries.

METHODS

Images and demographic information from 120 patients who underwent ACL reconstruction surgery were used for this study. An AI-driven model was developed to measure the posterior lateral tibial slope using the YOLOv8 algorithm. The accuracy of the lateral tibial slope, medial tibial slope and tibial longitudinal axis measurements was assessed, and the results reached high levels of reliability. This study employed machine learning and AI techniques to provide objective, consistent and efficient measurements of tibial slopes on MR images.

RESULTS

Three distinct models were developed to derive AI-based measurements. The study results revealed a substantial correlation between the measurements obtained from the AI models and those obtained by the orthopaedic surgeon across three parameters: lateral tibial slope, medial tibial slope and tibial longitudinal axis. Specifically, the Pearson correlation coefficients were 0.673, 0.850 and 0.839, respectively. The Spearman rank correlation coefficients were 0.736, 0.861 and 0.738, respectively. Additionally, the interclass correlation coefficients were 0.63, 0.84 and 0.84, respectively.

CONCLUSION

This study establishes that the deep learning-based method for measuring posterior tibial slopes strongly correlates with the evaluations of expert orthopaedic surgeons. The time efficiency and consistency of this technique suggest its utility in clinical practice, promising to enhance workflow, risk assessment and the customization of patient treatment plans.

LEVEL OF EVIDENCE

Level III, cross-sectional diagnostic study.

Does posterior tibial slope laterality exist? A matched cohort study between ACL-injured and non-injured knees

PURPOSE

The purpose of this study is to examine 1) the degree and frequency of laterality in posterior tibial slope (PTS) with control and anterior cruciate ligament (ACL) injury groups and 2) the laterality of PTS between sides of injury and dominant legs in patients with primary ACL injuries.

METHODS

A total of 187 consecutive patients with clinically diagnosed noncontact ACL injuries and an age- and sex-matched 1:1 control group were identified. PTS was measured using three different methods (aPTS = anterior PTS, mPTS = middle PTS, pPTS = posterior PTS) on a lateral knee radiograph. PTS of the left and right sides were compared between the patients in the control and ACL-injured groups, and between the injured and non-injured and dominant and non-dominant legs among the patients in the ACL-injured group. The patients with a difference in PTS of ≥ 3° in mPTS were selected. The percentages were compared between left and right between and among both groups, and between the injured and non-injured, and non-dominant and dominant leg, for the ACL group. Multiple regression analysis was performed to analyze the factors influencing the degree of mPTS.

RESULTS

Both control (Right vs Left: aPTS; 9.0 ± 2.5 vs 10.5 ± 3.0, mPTS; 6.6 ± 2.3 vs 8.1 ± 2.7, pPTS; 4.0 ± 2.4 vs 5.6 ± 2.8, respectively, p < 0.01) and ACL injury groups (Right vs Left: aPTS; 10.6 ± 3.0 vs 12.6 ± 2.9, mPTS; 7.6 ± 2.6 vs 9.5 ± 2.6, pPTS; 5.9 ± 3.0 vs 8.0 ± 3.0, respectively, p < 0.01) had a significantly greater PTS on the left than on the right side, and the ACL group had a significantly greater PTS than the control group on both the left and right sides. In the ACL group, PTS was greater on the injured and the non-dominant leg than on the non-injured and the dominant leg. The percentage of patients with a PTS difference of ≥ 3° was significantly greater on the left, injured, and non-dominant leg (95.3% vs 4.7%, 73.8% vs 26.2%, 86.1% vs 13.9%, respectively, p < 0.01). Only the left leg had a significant influence on PTS in the multivariate analysis.

CONCLUSION

There was laterality in PTS within control and ACL injury groups, and this information is of benefit for effective treatment of ACL injuries.

LEVEL OF EVIDENCE

Level III.

Association Between Posterior Tibial Slope and Clinical Outcomes After Isolated Anterior Cruciate Ligament Reconstructions

Background Increased posterior tibial slope (PTS) is an important risk factor for non-traumatic graft failure and revision surgery after anterior cruciate ligament reconstruction. If a tibial posterior slope is an important factor for graft failure after anterior cruciate ligament reconstruction, does it affect clinical outcomes? This study aimed to evaluate the association between PTS and clinical outcomes after anterior cruciate ligament reconstruction. Material and methods Patients undergoing arthroscopic anterior cruciate ligament reconstruction with hamstring tendons in the clinic were evaluated retrospectively. Inclusion criteria were: patients with at least an 18-month follow-up period who were evaluated with the Tegner Lysholm scoring system, aged between 18 and 40 years, with only an anterior cruciate ligament rupture. PTSs were measured from the lateral radiographs of the knees. The patients were divided into two groups with a PTS of 10° or less. Results The mean Tegner Lysholm score was 86.8 ± 8.9. The mean PTS was 9.7° ± 1.5°. In total, 14 and 15 patients had a PTS of above 10° and below 10°, respectively. The mean age and follow-up time of patients were 28.5 ± 5.3 years and 24.6 ± 7.2 months in the group with a PTS of above 10° and 30.2 ± 5.3 years and 24.2 ± 5.18 months in the group with a PTS of below 10°, respectively. Tegner Lysholm scores were 88.2 ± 8.8 and 85.6 ± 9.1 in the group with values above 10° and below 10°, respectively. Statistically, there was no significant difference between the clinical outcomes of both groups. Conclusion PTS does not affect the clinical outcomes of patients who underwent arthroscopic anterior cruciate ligament reconstruction in the early period.

Posterior tibial slope (PTS) ≥ 10 degrees is a risk factor for further anterior cruciate ligament (ACL) injury; BMI is not

PURPOSE

This case-control study aimed to assess the influence of BMI and PTS on subsequent ACL injury affecting either ACL graft or the native ACL of the contralateral knee after primary ACL reconstruction.

METHODS

A retrospective case-control study was performed using a cohort of patients who underwent arthroscopic ACL reconstruction between 2010 and 2020 using the same surgical procedure: Hamstring tendon autograft. The study group (group I) included all the patients (n = 94) during this period who sustained a subsequent ACL injury. The control group (group II) consisted of 94 patients randomly selected (matched Group I in terms of sex, age, and ACL graft) who did not sustain any further ACL injury. PTS was measured by two blinded surgeons on lateral knee view radiographs of the operated knee after primary ACL. BMI in kg/m2 was measured during the preoperative anesthesia consultation. Exclusion criteria were: non-true or rotated lateral knee radiographs of the operated knee post-ACLR, associated knee ligament injury requiring surgical management, iterative knee surgeries, open growth plate, and related fracture.

RESULTS

The mean posterior tibial slope in group I was 7.5° ± 2.9, and 7.2° ± 2.0 in group II. A PTS angle cutoff was set at 10 degrees. The rate of patients showing a PTS ≥ 10° was significantly higher in group I compared to group II (p < 0.01). Patients with PTS ≥ 10° were 5.7 times more likely to sustain a subsequent ACL injury, (OR: 5.7 95% CI[1.858-17.486]). The Average BMI in group I was 24.5 ± 3.7 kg.m-2 compared to group II which was 23.3 ± 3.0 kg.m-2. There were no significant differences in any of the four BMI categories between both groups (p value 0.289). A series of BMI cut-offs were also analyzed at 23 to30 kg/m2, and there was no significant difference between both groups.

CONCLUSIONS

A posterior tibial slope equal to or above 10 degrees measured on lateral knee radiographs was associated with 5.7 times higher risk of ACL graft rupture or contralateral native ACL injury; however, BMI was not.

External stimulation: A potential therapeutic strategy for tendon-bone healing

Injuries at the tendon-bone interface are very common in the field of sports medicine, and healing at the tendon-bone interface is complex. Injuries to the tendon-bone interface can seriously affect a patient’s quality of life, so it is essential to restore stability and promote healing of the tendon-bone interface. In addition to surgical treatment, the healing of tendons and bones can also be properly combined with extracorporeal stimulation therapy during the recovery process. In this review, we discuss the effects of extracorporeal shock waves (ESWs), low-intensity pulsed ultrasound (LIPUS), and mechanical stress on tendon-bone healing, focusing on the possible mechanisms of action of mechanical stress on tendon-bone healing in terms of transcription factors and biomolecules. The aim is to provide possible therapeutic approaches for subsequent clinical treatment.

Failure modes after anterior cruciate ligament reconstruction: a systematic review and meta-analysis

PURPOSE

The reason for graft failure after anterior cruciate ligament reconstruction (ACLR) is multifactorial. Controversies remain regarding the predominant factor and incidence of failure aetiology in the literature. This review aimed to provide a meta-analysis of the literature to evaluate the relative proportion of various failure modes among patients with ACLR failure.

METHODS

The PubMed, Embase, Cochrane Library, Web of Science, and EBSCO databases were searched for literature on ACLR failure or revision from 1975 to 2021. Data related to causes for ACLR surgical failure were extracted, and a random effects model was used to pool the results, which incorporates potential heterogeneity. Failure modes were compared between different populations, research methods, graft types, femoral portal techniques, and fixation methods by subgroup analysis or linear regression. Funnel plots were used to identify publication bias and small-study effects.

RESULTS

A total of 39 studies were analyzed, including 33 cohort studies and six registry-based studies reporting 6578 failures. The results showed that among patients with ACLR failure or revision, traumatic reinjury was the most common failure mode with a rate of 40% (95% CI: 35-44%), followed by technical error (34%, 95% CI: 28-42%) and biological failure (11%, 95% CI: 7-15%). Femoral tunnel malposition was the most common cause of the technical error (29%, 95% CI: 18-41%), with more than two times higher occurrence than tibial tunnel malposition (11%, 95% CI: 6-16%). Traumatic reinjury was the most common factor for ACLR failure in European populations and in recent studies, while technical errors were more common in Asian populations, earlier studies, and surgery performed using the transtibial (TT) portal technique. Biological factors were more likely to result in ACLR failure in hamstring (HT) autografts compared to bone-patellar tendon-bone (BPTB) autografts.

CONCLUSION

Trauma is the most important factor leading to surgical failure or revision following ACLR. Technical error is also an important contributing factor, with femoral tunnel malposition being the leading cause of error resulting in failure.

Elevated Posterior Tibial Slope Is Associated With Anterior Cruciate Ligament Reconstruction Failures: A Systematic Review and Meta-Analysis

PURPOSE

To evaluate the association of posterior tibial slope (PTS) with anterior cruciate ligament (ACL) reinjury following primary ACL reconstruction.

METHODS

PubMed, Scopus, Embase, and CINAHL databases were searched from inception through March 1, 2021, to retrieve relevant studies. Comparative studies reporting PTS measurements in a cohort of patients experiencing ACL graft failure versus patients with intact primary ACL reconstruction or studies comparing patients undergoing revision ACL reconstruction versus primary ACL reconstruction were included for analysis. A random-effects model was used to calculate the overall standardized mean difference (SMD) between groups. The following inclusion criteria were used: English language; full text available; Level I, II, or III evidence; studies in humans; and skeletally mature patients.

RESULTS

After we systematically screened 1,912 studies, 15 studies met the inclusion/exclusion criteria. Radiographic measurements were used in 6 studies reporting medial PTS in 411 ACL failures versus 2808 controls. Patients with ACL failure had significantly greater medial PTS compared with controls (SMD 0.50; 95% confidence interval [CI] 0.23-0.77; P < .001). Magnetic resonance imaging (MRI) was used in 9 studies reporting lateral PTS measurements in 641 patients with a failed ACL reconstruction compared with 705 controls. Seven of the MRI studies also measured medial PTS in 552 failures versus 641 controls. Patients with ACL failure had significantly greater lateral PTS on MRI (SMD 0.58; 95% CI 0.13-1.03; P = .012) and medial PTS on MRI (SMD 0.59; 95% CI 0.23-0.96; P = .001) compared with controls.

CONCLUSIONS

The present meta-analysis demonstrated that patients with elevated PTS on radiographs and MRI are at increased risk for ACL graft failure after primary ACL reconstruction.

LEVEL OF EVIDENCE

Level III, meta-analysis of Level III studies.

Multiple revision anterior cruciate ligament reconstruction: not the best but still good

PURPOSE

Given the paucity of literature on the re-revision of ACL, the current study was undertaken. The purpose of this systematic review was to synthesise and qualitatively assess the currently available evidence in the literature regarding the re-revision of ACL reconstruction (rrACLR).

METHODS

A systematic review was conducted based on the PRISMA guidelines. The following search terms were used in the title, abstract and keywords fields: "ACL" or "anterior cruciate ligament" AND "revision" or "multiple" or "repeat". The outcome data extracted from the studies were the Lysholm score, Subjective IKDC, Marx Score, Tegner, Marx Score, KOOS score, radiological changes and the rate of return to sports. Complications, failures and/or revision surgery were also analysed.

RESULTS

The cohort consisted of 295 patients [191 (64.7%) men and 104 (35.3%) women] with a mean age of 29.9 ± 2.8 years (range 14-58 years) from 10 studies. The mean postoperative follow-up (reported in all studies except one) was 66.9 ± 44.7 months (range 13-230.4 months). Associated injuries were 103 (34.9%) medial meniscus tears, 57 (19.3%) lateral meniscus tears, 14 (4.7%) combined medial plus lateral meniscus tears, 11 (3.7%) meniscal tears (not specified), 252 (85.4%) cartilage lesions, 6 (2.0%) medial collateral ligament injury and 2 (0.7%) lateral collateral ligament injuries. In 47 (15.9%) patients an extra-articular plasty was performed for the anterolateral ligament. In all studies that reported pre- and post-operative IKDC (subjective and objective) and Lysholm score, there was a significant improvement compared to the pre-operative value (p < 0.05). At the final follow-up, laxity measured with KT-1000 was found to be 2.2 ± 0.6 mm. 31 (10.5%) out of 295 patients returned to their pre-injury activity level. A total of 19 (6.4%) re-ruptures were found, while only 4 (1.4%) complications (all minors) were reported, out of which 2 (0.7%) were superficial infections, 1 (0.3%) cyclops lesion and 1 (0.3%) flexion loss.

CONCLUSION

Multiple revisions of anterior cruciate ligament reconstruction allow acceptable clinical results and a good degree of knee stability with a low rate of subsequent new re-ruptures but the possibility of regaining pre-injury sports activity is poor; whenever possible, it is preferred to revise the ligament in one stage. This surgery remains a challenge for orthopaedic surgeons and many doubts persist regarding the ideal grafts, additional extra-articular procedures and techniques to use.

LEVEL OF EVIDENCE

IV.

STUDY REGISTRATION

PROSPERO-CRD42022352164 ( https://www.crd.york.ac.uk/prospero/ ).

Advanced Gene Therapy Strategies for the Repair of ACL Injuries

The anterior cruciate ligament (ACL), the principal ligament for stabilization of the knee, is highly predisposed to injury in the human population. As a result of its poor intrinsic healing capacities, surgical intervention is generally necessary to repair ACL lesions, yet the outcomes are never fully satisfactory in terms of long-lasting, complete, and safe repair. Gene therapy, based on the transfer of therapeutic genetic sequences via a gene vector, is a potent tool to durably and adeptly enhance the processes of ACL repair and has been reported for its workability in various experimental models relevant to ACL injuries in vitro, in situ, and in vivo. As critical hurdles to the effective and safe translation of gene therapy for clinical applications still remain, including physiological barriers and host immune responses, biomaterial-guided gene therapy inspired by drug delivery systems has been further developed to protect and improve the classical procedures of gene transfer in the future treatment of ACL injuries in patients, as critically presented here.

Anatomic Factors Associated With the Development of an Anterior Cruciate Ligament Rerupture in Men: A Case-Control Study

BACKGROUND

Although several factors are associated with anterior cruciate ligament (ACL) rerupture, the effect of anatomic factors associated with ACL rupture on ACL rerupture development has not been evaluated.

PURPOSE

To determine individual anatomic parameters independently associated with ACL rerupture and the diagnostic values of these parameters.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A total of 91 male patients with ACL rerupture and 182 age-, sex-, body mass index-, and side dominance-matched patients without rerupture who underwent ACL reconstruction with a 5-year follow-up were included. In all, 35 parameters that were previously defined as risk factors for primary ACL rupture were compared between the 2 groups. Uni- and multivariate logistic regression models were created to evaluate independently associated factors. Receiver operating characteristic curve analysis was performed for independently associated parameters to predict sensitivity, specificity, and cutoff values.

RESULTS

The mean ± standard deviation age of patients at the time of index surgery was 26.5 ± 6.7 years. Notch shape index (P = .014), tibial proximal anteroposterior (AP) distance (TPAPD) (P < .001), lateral femoral condylar AP distance (LCAPD)/TPAPD ratio (P < .001), medial meniscal cartilage bone height (P < .001), and lateral meniscal bone angle (P = .004) were found to be significantly different between the 2 groups. Only the LCAPD/TPAPD ratio (odds ratio, 2.713; 95% CI, 1.998-5.480; P < .001) was found to be independently associated with ACL rerupture development. The LCAPD/TPAPD ratio revealed 78.9% sensitivity and 75.5% specificity (area under the curve, 0.815; 95% CI, 0.760-0.870) for values above 1.52.

CONCLUSION

The LCAPD/TPAPD ratio can be used to distinguish patients who are at risk of developing ACL rerupture from patients who are not. In the clinical practice, findings of this study may help to develop surgical and nonsurgical preventive strategies in ACL rerupture development.

Comparable Instrumented Knee Joint Laxity and Patient-Reported Outcomes After ACL Repair With Dynamic Intraligamentary Stabilization or ACL Reconstruction: 5-Year Results of a Randomized Controlled Trial

BACKGROUND

Technical innovation has led to the renaissance of anterior cruciate ligament (ACL) repair in the past decade.

PURPOSE/HYPOTHESIS

The present study aimed to compare instrumented knee joint laxity and patient-reported outcomes (PROs) after ACL repair with those after primary ACL reconstruction for acute isolated ACL tears. It was hypothesized that ACL repair would lead to comparable knee joint stability and PROs at 5 years postoperatively in comparison with ACL reconstruction.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 85 patients with acute ACL tears were randomized to undergo either ACL repair using dynamic intraligamentary stabilization (DIS) or primary ACL reconstruction with a semitendinosus tendon autograft. The primary outcome was the side-to-side difference in anterior tibial translation (ΔATT) assessed by Rolimeter testing at 5 years postoperatively. Follow-up examinations were performed at 1, 2, and 5 years. PROs were assessed using the Tegner activity scale, the International Knee Documentation Committee (IKDC) subjective score, and the Lysholm score. Furthermore, the rates of recurrent instability, other complications, and revision surgery were recorded. A power analysis was performed a priori, and the Friedman test, Mann-Whitney U test, and Bonferroni correction were applied for statistical comparisons with significance set at P < .05.

RESULTS

The mean age at inclusion was 28.3 ± 11.5 years in the ACL repair group and 27.1 ± 11.5 years in the ACL reconstruction group. At 5 years postoperatively, a total of 64 patients (ACL repair: n = 34 of 43 [79%]; ACL reconstruction: n = 30 of 42 [71%]) were available for follow-up. At 5 years, ΔATT was 1.7 ± 1.6 mm in the ACL repair group and 1.4 ± 1.3 mm in the ACL reconstruction group (P = .334). Preinjury PROs were restored as soon as 1 year after surgery and plateaued until 2 and 5 years postoperatively in both groups. At the 5-year follow-up, the mean Lysholm score was 97.0 ± 5.4 versus 94.5 ± 5.5 (P = .322), respectively, and the mean IKDC subjective score was 94.1 ± 9.9 versus 89.9 ± 7.8 (P = .047), respectively, in the ACL repair group versus ACL reconstruction group. At 5 years postoperatively, 12 patients in the ACL repair group (35%; age <25 years: n = 10/12; Tegner score ≥7: n = 10/12) had recurrent instability, of whom 10 underwent single-stage revision ACL reconstruction. In the ACL reconstruction group, there were 6 patients with recurrent instability (20%; age <25 years: n = 6/6; Tegner score ≥7: n = 5/6); however, in 5 patients, staged revision was required. Differences between both groups regarding recurrent instability (P = .09) or ACL revision surgery (P = .118) were not statistically significant. Recurrent instability was associated with age <25 years and Tegner score >7 in both groups.

CONCLUSION

At 5 years after ACL repair with DIS, instrumented knee joint laxity and PROs were comparable with those after ACL reconstruction. Although no significant difference was found between repair and reconstruction, a critical appraisal of the rates of recurrent instability (35% vs 20%, respectively) and revision surgery (38% vs 27%, respectively) is needed. Young age and a high preinjury activity level were the main risk factors for recurrent instability in both groups. However, single-stage revision ACL reconstruction was possible in each case in the ACL repair group. Although ACL reconstruction remains the gold standard in the treatment of ACL tears, the present study supports the use of ACL repair with DIS as a feasible option to treat acute ACL tears in patients aged ≥25 years with low to moderate activity levels (Tegner score <7).

REGISTRATION

DRKS00015466 (German Clinical Trials Register).

Anterior Closing Wedge Osteotomy for Failed Anterior Cruciate Ligament Reconstruction: State of the Art

The sagittal anatomy of the proximal tibia has a bearing on the forces exerted on the cruciate ligaments. A high posterior tibial slope is now a well-known risk factor causing failure of anterior cruciate ligament (ACL) reconstructions. The posterior slope can be calculated on short or full-length radiographs, MRI scans, or three-dimensional CT scans. Reducing the slope surgically by a sagittal tibial osteotomy is biomechanically protective for the ACL graft. An anterior closing wedge osteotomy may be contemplated when the lateral tibial slope is greater than 12°, in the setting of ACL reconstruction failure(s). Careful surgical planning to calculate the correction, taking into account knee hyperextension and patella height, is critical to avoid complications. It can be done above, at, or below the tibial tuberosity level. A transtuberosity correction can be done with or without a tibial tubercle osteotomy. This complex surgery can be conducted safely by meticulous execution to protect the posterior hinge and neurovascular structures and achieving stable fixation with staples. The limited literature available justifies the usage of anterior closing wedge osteotomy in appropriately selected patients.

Revision ACL reconstruction has higher incidence of 30-day hospital readmission, reoperation, and surgical complications relative to primary procedures

PURPOSE

Although there has been substantial improvement in ACL reconstructive surgery, graft failure remains a devastating complication for some patients. Revision procedures are inherently more complex and technically challenging. The purpose of this study is to determine the incidence of short-term complications after these procedures and to compare trends in operative length, relative valuation, and reimbursement after primary versus revision ACL reconstruction.

METHODS

Primary and revision arthroscopic ACL reconstruction cases were identified on the American College of Surgeons' NSQIP database using Current Procedural Terminology (CPT) and International Classification of Diseases (ICD) codes between January 1, 2012 and December 31, 2017. Demographics, patient variables, and surgical variables were compared between primary and revision groups using Chi-squared tests. Logistic regression was used to identify independent risk factors for revision ACL reconstruction. Various 30-day outcome measures were compared between the primary and revision ACL reconstruction groups. Various measures of valuation-including total relative value units (RVU) and reimbursement per minute-were calculated and compared between the two groups.

RESULTS

A total of 8292 patients-8135 primary and 157 revision procedures-were included in the final cohort. Higher ASA scores were associated with revision ACL reconstructions. Patients undergoing revision procedures were less likely to have an ASA score of 1 (p < 0.001) and more likely to have an ASA score of 2 (p = 0.004) or 3 (p = 0.020). Revision ACL reconstruction was associated with higher rates of poor 30-day outcome measures, including unplanned readmission (p = 0.029), reoperation (p = 0.012), return to the OR (p = 0.012), and surgical complications (p = 0.021). The total RVUs and reimbursement for revision procedures were significantly greater than those for primary procedures (p < 0.001). However, when accounting for operative time, the RVU/minute and reimbursement/minute were similar between the two groups (n.s.).

CONCLUSIONS

Relative to primary ACL reconstruction, revision ACL procedures are associated with worse short-term outcomes-including unplanned readmission, reoperation, return to the OR, and surgical complications. A greater ASA score was independently predictive of revision ACL surgery. The current RVU system undervalues revision ACL procedures, considering the increased operative time and complexity of such procedures.

LEVEL OF EVIDENCE

Level III.

Posterior Tibial Slope in Patients With Torn ACL Reconstruction Grafts Compared With Primary Tear or Native ACL: A Systematic Review and Meta-analysis

Background:

Increased posterior tibial slope (PTS) is a risk factor for anterior cruciate ligament (ACL) rupture and failure of ACL reconstruction (ACLR) grafts.

Purpose:

The purpose was to conduct a systematic review of literature on PTS measurements and to conduct a meta-analysis of comparable PTS measurements based on a patient’s ACL status. It was hypothesized that patients with torn ACLR grafts would have significantly larger medial and lateral PTS compared with patients with native ACLs or those who underwent primary ACLR.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included were studies that reported medial and/or lateral PTS measurements, those that reported PTS measurements based on ACL status (ie, intact ACL, primary ACL tear, failed ipsilateral ACLR, or revision ACLR), and those that reported their specific PTS measurement technique. Average PTS measurements, measurement location (medial or lateral tibial plateau) and technique, imaging modality used, and ACL status were extracted from each study. Data were pooled using DerSimonian and Laird random-effects models, and results were compared using the Altman interaction test.

Results:

The literature search identified 1705 studies, of which 82 (N = 12,971 patients) were included. There were 4028 patients in the intact ACL group (31%), 7405 in the primary ACLR group (57%), and 1538 in the failed ACLR group (12%). Measurements were obtained from lateral radiographs in 31 studies (38%), from magnetic resonance imaging in 47 studies (57%), and from computed tomography in 4 studies (5%). The failed ACLR group had a significantly larger lateral PTS (9.55°; 95% CI, 8.47°-10.63°) than either the primary ACL tear (7.13°; 95% CI, 6.58°-7.67°) or intact ACL (5.57°; 95% CI, 5.03°-6.11°) groups (P < .001 for both). The failed ACLR group also had a significantly larger medial PTS (9.05°; 95% CI, 7.80°-10.30°) than the primary (6.24°; 95% CI, 5.71°-6.78°) or intact ACL (6.28°; 95% CI, 5.21°-7.35°) groups (P < .001 for both).

Conclusion:

Both lateral and medial PTS measurements were greater in patients who had failed previous ACLR than those with a primary ACL tear or an intact native ACL. The lateral PTS of patients with primary ACL tears was greater than those with an intact native ACL.

Anterior Cruciate Ligament Reconstruction: Is Biological Augmentation Beneficial?

Surgical reconstruction in anterior cruciate ligament (ACL) ruptures has proven to be a highly effective technique that usually provides satisfactory results. However, despite the majority of patients recovering their function after this procedure, ACL reconstruction (ACLR) is still imperfect. To improve these results, various biological augmentation (BA) techniques have been employed mostly in animal models. They include: (1) growth factors (bone morphogenetic protein, epidermal growth factor, granulocyte colony-stimulating factor, basic fibroblast growth factor, transforming growth factor-β, hepatocyte growth factor, vascular endothelial growth factor, and platelet concentrates such as platelet-rich plasma, fibrin clot, and autologous conditioned serum), (2) mesenchymal stem cells, (3) autologous tissue, (4) various pharmaceuticals (matrix metalloproteinase-inhibitor alpha-2-macroglobulin bisphosphonates), (5) biophysical/environmental methods (hyperbaric oxygen, low-intensity pulsed ultrasound, extracorporeal shockwave therapy), (6) biomaterials (fixation methods, biological coatings, biosynthetic bone substitutes, osteoconductive materials), and (7) gene therapy. All of them have shown good results in experimental studies; however, the clinical studies on BA published so far are highly heterogeneous and have a low degree of evidence. The most widely used technique to date is platelet-rich plasma. My position is that orthopedic surgeons must be very cautious when considering using PRP or other BA methods in ACLR.

Efficacy of Surgical Tenodesis for Treatment of Distal Semitendinosus Hamstring Tendon Injuries

Background:

Understanding the optimal management of distal semitendinosus hamstring injuries is critical for reducing pain, restoring preinjury function, maintaining knee stability, improving hamstring muscle strength, and minimizing the risk of complications and recurrence. To our knowledge, the outcomes of surgical tenodesis for distal semitendinosus hamstring injuries have not been previously reported.

Hypothesis:

Surgical tenodesis for injuries of the semitendinosus would enable return to preinjury level of sport with low risk of recurrence.

Study Design:

Case series; Level of evidence, 4.

Methods:

This prospective single-surgeon study included 13 professional athletes (12 men, 1 woman; mean age, 32 ± 8.2 years; mean body mass index, 26.7 ± 3.9 kg/m²) undergoing treatment for distal semitendinosus hamstring injuries with primary tenodesis to the distal semimembranosus. Indications for surgical tenodesis included distal semitendinosus tendon avulsion injury (n = 8) or residual tendon instability and hamstring weakness after semitendinosus graft harvest for anterior cruciate ligament reconstruction (n = 5). All study patients underwent a standardized postoperative rehabilitation program. The primary outcome was defined as time for return to sporting activity. Secondary outcomes were patient satisfaction, injury recurrence, and complications. The mean follow-up time was 17 months (range, 12-24 months) from date of surgery.

Results:

All study patients returned to their preinjury level of sporting activity. The mean time from the surgical intervention to return to full sporting activity was 15 ± 4.6 weeks. At 1-year follow-up, all study patients were still participating at their preinjury level of sporting activity, and 12 patients (92%) were very satisfied and 1 patient (8%) was satisfied about the outcomes of their surgery. No study patients had recurrence of the primary injury. No surgical complications, injury recurrence, or reoperations were observed within the follow-up period.

Conclusion:

Early return to sporting activity was seen after surgical tenodesis for distal semitendinosus hamstring injuries after acute trauma or residual symptoms following previous hamstring graft harvest, with high levels of patient satisfaction and low risk of recurrence at short-term follow-up.

Multiple ACL Revision: Failure Analysis and Clinical Outcomes

Anterior cruciate ligament (ACL) reconstruction represents one of the most successful orthopedic surgical procedures. Nevertheless, ACL revisions are still very frequent, with a small but relevant number of failures. The purpose of this study is to analyze the failure causes and the clinical outcomes of patients who underwent a re-revision ACL reconstruction. Between January 2009 and December 2017, 263 ACL revisions were performed by a single senior surgeon. Seventeen patients (12 males and 5 females) underwent re-revision ACL reconstruction meeting the inclusion criteria. The mean age was 28.4 years (range, 19-41 years). Before the re-revision, the patients were evaluated preoperatively and after a mean follow-up of 29 months (range, 13-58 months). Assessment included subjective and objective evaluations (Lysholm and International Knee Documentation Committee [IKDC]), KT-2000 arthrometer, radiographic study, and preoperative computed tomography scan. Five patients showed a too anterior previous femoral tunnel and seven a too vertical and posterior tibial tunnel; eight meniscal tears were found. Five patients had grade III-IV according to Outerbridge cartilage lesions. IKDC showed a statistically significant improvement (A + B 35%, C + D 65% preop, A + B 82%, C + D 18% postop, odds ratio: 0.1169; p = 0.0083). The mean Lysholm score ranged from 43 ± 9 to 87 ± 7 (p < 0.001). The KT-2000 arthrometer showed a statistically significant improvement from a mean of 5.8 ± 1.4 to 1.5 ± 1.1 (p < 0.001) at last follow-up. Out of 17 patients, only 4 returned to sports activity at the same preinjury levels. Postoperatively at the last follow-up after last revision surgery, no osteoarthritis evolution was observed. This study showed good clinical and radiological results after the last revision ACL surgery in patients with multiple failures of ACL reconstruction but only one-fourth of the patients returned to the same preoperative sport level. Traumatic events, technical errors, and untreated peripheral lesions are the main causes of multiple previous failures; the worst clinical outcomes were found in the patients with high grade of chondral lesions.

Higher risk of contralateral anterior cruciate ligament (ACL) injury within 2 years after ACL reconstruction in under-18-year-old patients with steep tibial plateau slope

PURPOSE

To assess the role of Tibial Plateau Slope (TPS) as risk factor for early Anterior Cruciate Ligament (ACL) reconstruction failure and contralateral ACL injury in a population of patients with less than 18 years of age and operated on with the same surgical technique.

METHODS

Ninety-four consecutive patients (mean age 15.7 ± 1.5 years) with at least 2 years of follow-up, who underwent ACL reconstruction with a single-bundle plus lateral-plasty hamstring technique in the same centre were included. Subsequent ACL injuries (ipsilateral ACL revision or contralateral ACL reconstruction) were assessed within the first 2 years after surgery. Anterior, central, posterior TPS of medial compartment were measured on lateral radiographs and compared between patients with intact graft and those with a second injury. Cut-off values with sensitivity and specificity were calculated with receiver operating characteristic (ROC) analysis. Survival analysis for second ACL injuries and multivariate analysis were performed.

RESULTS

Eight patients (9%) had ipsilateral ACL Revision and eight patients (9%) had contralateral ACL reconstruction. Patients with contralateral injury had a higher Central TPS with respect to those without second injury (12.6° ± 2.8° vs 9.3° ± 3.7°, p = 0.042). No differences were present in patients with ipsilateral ACL revision. Sensitivity and specificity for central TPS slope ≥ 12° to detect a contralateral rupture were 63% and 75% (p = 0.0092), for Anterior TPS were 100% and 52% (p = 0.0009). Patients with TPS values exceeding these cut-offs had higher rate of contralateral ACL injuries (19%vs4%, p = 0.0420) and lower 2-year survival (p = 0.0049). Multivariate analysis identified pre-operative sport level and TPS (either anterior or central) as risk factors for contralateral injuries.

CONCLUSIONS

Steep tibial plateau slope ≥ 12° is associated with a higher risk of contralateral ACL injury within 2 years after ACL reconstruction in patients less than 18 years of age. However, TPS has no role in early ipsilateral re-injury after combined ACL reconstruction and lateral plasty. The clinical relevance is that both the surgeon and the patient should be aware of this higher risk and consider it in the rehabilitation phase to reduce the incidence of such injuries.

LEVEL OF EVIDENCE

III.

Trauma and femoral tunnel position are the most common failure modes of anterior cruciate ligament reconstruction: a systematic review

PURPOSE

To improve outcomes of anterior cruciate ligament reconstruction (ACLR), it is important to understand the reasons for failure of this procedure. This systematic review was performed to identify current failure modes of ACLR.

METHODS

A systematic search was performed using PubMed, EMBASE, Cochrane, and annual registries for ACLR failures. Studies were included when failure modes were reported (I) of ≥ 10 patients and (II) at a minimum of two-year follow-up. Modes of failure were also compared between different graft types and in femoral tunnel positions.

RESULTS

This review included 24 cohort studies and 4 registry-based studies (1 level I, 1 level II, 10 level III, and 16 level IV studies). Overall, a total of 3657 failures were identified. The most common single failure mode of ACLR was new trauma (38%), followed by technical errors (22%), combined causes (i.e. multiple failure mechanisms; 19%), and biological failures (i.e. failure due to infection or laxity without traumatic or technical considerations; 8%). Technical causes also played a contributing role in 17% of all failures. Femoral tunnel malposition was the most common cause of technical failure (63%). When specifically looking at the bone-patellar tendon-bone (BPTB) or hamstring (HT) autografts, trauma was the most common failure mode in both, whereas biological failure was more pronounced in the HT group (4% vs. 22%, respectively). Technical errors were more common following transtibial as compared to anteromedial portal techniques (49% vs. 26%).

CONCLUSION

Trauma is the single leading cause of ACLR failure, followed by technical errors, and combined causes. Technical errors seemed to play a major or contributing role in large part of reported failures, with femoral tunnel malposition being the leading cause of failure. Trauma was also the most common failure mode in both BPTB and HT grafts. Technical errors were a more common failure mode following transtibial than anteromedial portal technique.

LEVEL OF EVIDENCE

IV.

Influence of Posterior Tibial Slope on Clinical Outcomes and Survivorship After Anterior Cruciate Ligament Reconstruction Using Hamstring Autografts: A Minimum of 10-Year Follow-Up

PURPOSE

To investigate the influence of medial and lateral posterior tibial slope (PTS) on long-term clinical outcomes and survivorship after anterior cruciate ligament (ACL) reconstruction using hamstring autografts.

METHODS

A total of 232 patients (mean age, 28.2 ± 8.9 years) who underwent primary ACL reconstruction from October 2002 to July 2007 were retrospectively reviewed. Patients with multiple ligament reconstruction, total meniscectomy, contralateral knee surgery before ACL reconstruction, open growth plate, and less than 10-year follow-up were excluded in the study. The medial and lateral PTS were measured from preoperative magnetic resonance imaging. Based on Li et al.'s previous study, the patients were divided into 2 groups according to their medial PTS (≤5.6° vs >5.6°) and lateral PTS (≤3.8° vs >3.8°), respectively. Clinical outcomes (clinical scores, stability tests and failure rate) were compared between the groups at the last follow-up. Furthermore, survival analysis was performed using the Kaplan-Meier method.

RESULTS

All clinical scores (International Knee Documentation Committee subjective, Lysholm, and Tegner activity scores) and stability tests (physical examinations and side-to-side difference in Telos stress radiographs) were insignificantly different between the 2 groups classified based on medial or lateral PTS. However, the failure rate was significantly higher in patients with medial PTS >5.6° (16.1% vs 5.1%, P = .01) or lateral PTS >3.8° (14.5% vs 4.7%; P = .01). The odds ratios of graft failure due to increased medial and lateral PTS were 3.18 (95% confidence interval, 1.22-8.28; P = .02) and 3.43 (95% confidence interval, 1.29-9.09; P = .01), respectively. In addition, the 10-year survivorship was significantly lower in patients with medial PTS >5.6° (83.9% vs 94.9%, P = .01) or lateral PTS >3.8° (85.5% vs 96.0%; P = .01).

CONCLUSIONS

Increased medial (>5.6°) and lateral (>3.8°) PTS were associated with higher failure rate and lower survivorship at a minimum of 10-year follow-up after primary ACL reconstruction using hamstring autografts.

LEVEL OF EVIDENCE

Level III, retrospective comparative trial.

[Arthroscopic reconstruction of anterior cruciate ligament with autologous ipsilateral peroneus longus tendon]

Objective

To investigate the effectiveness of anterior cruciate ligament (ACL) reconstruction with the autologous ipsilateral peroneus longus tendon (PLT) under arthroscopy.

Methods

A retrospective study was conducted on 35 patients with ACL rupture who underwent ACL reconstruction with autologous ipsilateral PLT under arthroscopy between October 2017 and October 2018. There were 19 males and 16 females with an average age of 43.4 years (range, 18-60 years), with 20 cases of left knee and 15 cases of right knee. The causes of injury included traffic accident in 14 cases, falling injury in 13 cases, and sports injury in 8 cases. The time from injury to operation ranged from 3 to 9 days (mean, 4.7 days). The patients suffered from swelling, pain, and limited mobility of knee joint before operation. The anterior drawer test, Lachman test, and pivot-shift test were positive before operation, whereas MRI was taken to confirm the ACL rupture. After operation, the patients were followed up every 3 months until the knee joint's function returned to normal. MRI and X-ray films were used to observe the tendon-bone healing as well as the position of Endobutton suspension plate and hollow nail. The anterior drawer test, Lachman test, and pivot-shift test were conducted to observe the improvement of knee joint mobility. The functional improvements were evaluated by the International Knee Documents Committee (IKDC) score, Lysholm score, knee injury and osteoarthritis (KOOS) score.

Results

All the 35 patients were followed up 12-18 months, with an average of 14.2 months. The incisions healed by first intention, and no complications such as infection, joint stiffness, and rerupture occurred. Postoperative anterior drawer test, Lachman test, and pivot-shift test turned to be negative of all patients. MRI showed that the ACL was continuous, and the tendon-bone in the distal femur tunnel and proximal tibia tunnel recovered well after operation. X-ray films showed that the positions of Endobutton suspension plate and hollow nail were stable. The IKDC, Lysholm, and KOOS scores at 3, 6, and 12 months after operation were significantly improved when compared with those before operation, and the scores were further improved with time after operation ( P<0.05).

Conclusion

For patients with ACL rupture, ACL reconstruction with the autologous ipsilateral PLT under arthroscopy has satisfactory effectiveness of quick recovery, good function, and great stability.

Satisfactory functional and MRI outcomes at the foot and ankle following harvesting of full thickness peroneus longus tendon graft

AIMS

To evaluate the donor site morbidity and tendon morphology after harvesting whole length, full-thickness peroneus longus tendon (PLT) proximal to the lateral malleolus for ligament reconstructions or tendon transfer.

METHODS

A total of 21 eligible patients (mean age 34.0 years (standard deviation (SD) 11.2); mean follow-up period 31.8 months (SD 7.7), and 12 healthy controls (mean age, 26.8 years (SD 5.9) were included. For patients, clinical evaluation of the donor ankle was performed preoperatively and postoperatively. Square hop test, ankle strength assessment, and MRI of distal calf were assessed bilaterally in the final follow-up. The morphological symmetry of peroneal tendons bilaterally was evaluated by MRI in healthy controls.

RESULTS

Among the patients, the mean pre- and postoperative American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score and Karlsson-Peterson score were 98.7 (SD 2.5; p = 0.480) and 98.5 (SD 2.4; p = 0.480), and 98.3 (SD 2.4; p = 0.162) and 97.9 (SD 2.5; p = 0.162), respectively. There was no significant difference between square hop test bilaterally (p = 0.109) and plantar flexion peak force bilaterally (p = 0.371). The harvested limb had significantly less eversion peak force compared to the contralateral limb (p < 0.001). Evidence of probable tendon regeneration was observed in all the patients by MRI and the total bilateral peroneal tendon index (mean ratio of harvested side cross-sectional area of peroneal tendon compared with the contralateral side) was 82.9% (SD 17.4). In 12 healthy controls, peroneal tendons (mean 99.4% (SD 4.3) were found to be morphologically symmetrical between the two sides.

CONCLUSION

The current study showed satisfactory clinical foot and ankle outcomes after full-thickness PLT harvesting and indicated the regenerative potential of PLT after its removal. Level of Evidence: Level IV, therapeutic retrospective case series. Cite this article: Bone Joint J 2020;102-B(2):205-211.

Paediatric and adolescent anterior cruciate ligament reconstruction surgery

Aims

Anterior cruciate ligament (ACL) surgery in children and the adolescent population has increased steadily over recent years. We used a national database to look at trends in ACL reconstruction and rates of serious complications, growth disturbance, and revision surgery, over 20 years.

Methods

All hospital episodes for patients undergoing ACL reconstruction, under the age of 20 years, between 1 April 1997 and 31 March 2017, were extracted by procedure code from the national Hospital Episode Statistics (HES). Population standardized rates of intervention were determined by age group and year of treatment. Subsequent rates of serious complications including reoperation for infection, growth disturbance (osteotomy, epiphysiodesis), revision reconstruction, and/or contralateral ACL reconstruction rates were determined.

Results

Over the 20 year period, 16,125 ACL reconstructions were included. The mean age of patients was 16.9 years (SD 2.0; 27.1% female, n = 4,374/16,125). The majority of procedures were observed in the 15 to 19 years age group. The rate of ACL reconstruction increased 29-fold from 1997 to 1998, to 2016 to 2017. Within 90 days of ACL reconstruction, the rate of reoperation for infection was 0.31% (95% confidence interval (CI) 0.23 to 0.41, n = 50/16,125) and the rate of pulmonary embolism was 0.037% (95%.CI 0.014 to 0.081, n = 6/16,125). Of those with minimum five-year follow-up following ACL reconstruction (n = 7,585), 1.00% of patients subsequently underwent an osteotomy (95% CI 0.79 to 1.25, n = 76/7,585), 0.09% an epiphysiodesis (95% CI 0.04 to 0.19, n = 7/7,585), 7.46% revision ACL reconstruction (95% CI 6.88 to 8.08, n = 566/7,585), and 6.37% contralateral ACL reconstruction (95% CI 5.83 to 6.94, n = 483/7,585).

Conclusion

Rates of paediatric and adolescent ACL reconstruction have increased 29-fold over the last 20 years. Despite the increasing rate in the younger population, the risk of serious complications, including further surgery for growth disturbance is very low. The results of our study provide a point of reference for shared decision making in the management of ACL injury in the paediatric and adolescent population. Cite this article: Bone Joint J 2020;102-B(2):239–245.

Return to Sport Tests' Prognostic Value for Reinjury Risk after Anterior Cruciate Ligament Reconstruction: A Systematic Review

INTRODUCTION

Return to sports (RTS) clearance after anterior cruciate ligament (ACL) reconstruction typically includes multiple assessments. The ability of these tests to assess the risk of a reinjury remains unknown.

PURPOSE

To assess and rate RTS self-reported function and functional tests on prognostic value for reinjury risk after ACL reconstruction and RTS.

STUDY DESIGN

Systematic review on level 2 studies.

METHODS

PubMed, Web of Knowledge, Cochrane Library, and Google Scholar databases were searched for articles published before March 2018. Original articles in English or German that examined reinjury risks/rates after primary (index) ACL injury, ACL reconstruction, and RTS were included. All RTS functional tests used in the included studies were analyzed by retrieving an effect size with predictive value (odds ratio, relative risk (risk ratio), positive predictive value, positive likelihood ratio, or hazard rate).

RESULTS

A total of 276 potential studies were found; eight studies (moderate to high quality) on 6140 patients were included in the final analysis. The reinjury incidence recorded in the included studies ranged from 1.5% to 37.5%. Four studies reported a combination of isokinetic quadriceps strength at different velocities and a number of hop tests as predictive with various effect sizes. One reported isokinetic hamstring to quadriceps ratio (hazard rate = 10.6) as predictive. Two studies reported functional questionnaires (knee injury and osteoarthritis outcome score and Tampa Scale of Kinesiophobia-11; RR = 3.7-13) and one study showed that kinetic and kinematic measures during drop vertical jumps were predictive (odds ratio, 2.3-8.4) for reinjury and/or future revision surgery.

CONCLUSIONS

Based on level 2 evidence, passing a combination of functional tests with predetermined cutoff points used as RTS criteria is associated with reduced reinjury rates. A combination of isokinetic strength and hop tests is recommended during RTS testing.

Tibial slope and medial meniscectomy significantly influence short-term knee laxity following ACL reconstruction

PURPOSE

To determine demographic, anatomic, and surgical factors associated with static and dynamic Anterior Tibial Translation (ATT) following ACL reconstruction. The hypothesis was that both static and dynamic ATT would be greater in knees with high tibial slope or that required meniscectomy.

METHODS

The authors prospectively enrolled 280 consecutive patients that had primary ACL reconstruction using hamstring autografts at one center for which preoperative tear type, meniscal tears, and medial tibial slope were documented. A total of 137 were excluded due to concomitant extra-articular tenodesis or surgical antecedents on either knee, and 18 were lost to follow-up, leaving 125 that were evaluated at a minimum of 6 months including: static ATT on monopodal weight-bearing radiographs, and dynamic ATT on differential stress radiographs using the Telos™ device.

RESULTS

Both postoperative static and dynamic ATT were strongly associated with preoperative static and dynamic ATT (respectively, β = 0.068 and β = 0.50, p < 0.001). Multivariable regression confirmed that postoperative static ATT increased with tibial slope (β = 0.24; CI 0.01-0.47; p = 0.042) and in knees that had partial medial meniscectomy (β = 2.05; CI 0.25-3.84; p = 0.025), while dynamic ATT decreased with age (β = - 0.11; CI - 0.16 to - 0.05; p < 0.001), and increased with tibial slope (β = 0.27; CI 0.04-0.49; p = 0.019) and in knees that had partial medial meniscectomy (β = 2.20; CI 0.35-4.05; p = 0.019).

CONCLUSION

Both static and dynamic ATT following ACL reconstruction increased with tibial slope and in knees that had partial medial meniscectomy. These findings could help surgeons tailor their techniques and 'à la carte' rehabilitation protocols, by preserving the menisci and sometimes delaying full weight-bearing and return to sport in patients at risk, and hence improve outcomes and prevent graft failures.

STUDY DESIGN

Cohort study.

LEVEL OF EVIDENCE

V.

Posterior cruciate ligament injury is influenced by intercondylar shape and size of tibial eminence

AIMS

Little is known about the risk factors that predispose to a rupture of the posterior cruciate ligament (PCL). Identifying risk factors is the first step in trying to prevent a rupture of the PCL from occurring. The morphology of the knee in patients who rupture their PCL may differ from that of control patients. The purpose of this study was to identify any variations in bone morphology that are related to a PCL.

PATIENTS AND METHODS

We compared the anteroposterior (AP), lateral, and Rosenberg view radiographs of 94 patients with a ruptured PCL to a control group of 168 patients matched by age, sex, and body mass index (BMI), but with an intact PCL after a knee injury. Statistical shape modelling software was used to assess the shape of the knee and determine any difference in anatomical landmarks.

RESULTS

We found shape variants on the AP and Rosenberg view radiographs to be significantly different between patients who tore their PCL and those with an intact PCL after a knee injury. Overall, patients who ruptured their PCL have smaller intercondylar notches and smaller tibial eminences than control patients.

CONCLUSION

This study shows that differences in the shape of the knee are associated with the presence of a PCL rupture after injury. A smaller and more sharply angled intercondylar notch and a more flattened tibial eminence are related to PCL rupture. This suggests that the morphology of the knee is a risk factor for sustaining a PCL rupture. Cite this article: Bone Joint J 2019;101-B:1058-1062.

Patients With Failed Anterior Cruciate Ligament Reconstruction Have an Increased Posterior Lateral Tibial Plateau Slope: A Case-Controlled Study

PURPOSE

To compare knee anatomical parameters of patients with failed anterior cruciate ligament reconstruction (ACL-R) with those of a control group of sex-matched patients with successful ACL-R.

METHODS

Forty-three patients (34 male, 9 female) who experienced graft failure after ACL-R were enrolled in the failed group. These patients were matched to a control group of 43 patients who underwent primary ACL-R with a minimum follow-up of 24 months. On magnetic resonance imaging, the following parameters were evaluated: transepicondylar distance, lateral and medial femoral condyle widths, tibial plateau width, notch width index, and the ratio of width and height of the femoral notch, ratio between the height and depth of the lateral and medial femoral condyle, lateral and medial posterior tibial slopes, and anterior subluxation of the lateral and medial tibial plateau. Multivariate regression with backward elimination, including only the previously identified significant variables, defined the independent predictors for revision surgery.

RESULTS

The anatomical variables that were significantly different between the 2 study groups were lateral and medial posterior tibial slopes, anterior subluxation of the lateral and medial tibial plateau, medial tibial plateau width, lateral tibial plateau width, medial femoral condyle width, and transepicondylar distance; however, the multivariate regression analysis identified the lateral posterior tibial slope (LTPs), the anterior subluxation of the medial tibial plateau, and the medial femoral condyle width as significant independent predictors (P < .05). The LPTs had the highest coefficient and the highest sensitivity (88%) and specificity (84%) to identify failures when considering the optimal cutoff value of 7.4°.

CONCLUSIONS

Several anatomical parameters have been identified that differ significantly between patients with failed ACL-R and those without a documented failure. The most accurate predictor of ACL failure was an LTPs >7.4°, with a sensitivity of 88% and specificity of 84%. Surgeons should consider measuring LTPs during preoperative assessment of ACL-injured patients, and patients with values >7.4° should be considered at high risk of ACL-R failure.

LEVEL OF EVIDENCE

Level III retrospective prognostic trial.

Steep Posterior Tibial Slope, Anterior Tibial Subluxation, Deep Posterior Lateral Femoral Condyle, and Meniscal Deficiency Are Common Findings in Multiple Anterior Cruciate Ligament Failures: An MRI Case-Control Study

BACKGROUND

Tibiofemoral anatomic parameters, such as tibial slope, femoral condyle shape, and anterior tibial subluxation, have been suggested to increase the risk of anterior cruciate ligament (ACL) reconstruction failure. However, such features have never been assessed among patients experiencing multiple failures of ACL reconstruction.

PURPOSE

To compare the knee anatomic features of patients experiencing a single failure of ACL reconstruction with those experiencing multiple failures or with intact ACL reconstruction.

STUDY

Case-control study; Level of evidence, 3.

METHODS

Twenty-six patients who experienced failure of revision ACL reconstruction were included in the multiple-failure group. These patients were matched to a group of 25 patients with failure of primary ACL reconstruction and to a control group of 40 patients who underwent primary ACL reconstruction with no failure at a minimum follow-up of 24 months. On magnetic resonance imaging (MRI), the following parameters were evaluated: ratio between the height and depth of the lateral and medial femoral condyles, the lateral and medial tibial plateau slopes, and anterior subluxation of the lateral and medial tibial plateaus with respect to the femoral condyle. The presence of a meniscal lesion during each procedure was evaluated as well. Anatomic, demographic, and surgical characteristics were compared among the 3 groups.

RESULTS

The patients in the multiple-failure group had significantly higher values of lateral tibial plateau slope ( P < .001), medial tibial plateau slope ( P < .001), lateral tibial plateau subluxation ( P < .001), medial tibial plateau subluxation ( P < .001), and lateral femoral condyle height/depth ratio ( P = .038) as compared with the control group and the failed ACL reconstruction group. Moreover, a significant direct correlation was found between posterior tibial slope and anterior tibial subluxation for the lateral ( r = 0.325, P = .017) and medial ( r = 0.421, P < .001) compartments. An increased anterior tibial subluxation of 2 to 3 mm was present in patients with a meniscal defect at the time of the MRI as compared with patients who had an intact meniscus for both the lateral and the medial compartments.

CONCLUSION

A steep posterior tibial slope and an increased depth of the lateral femoral condyle represent a common finding among patients who experience multiple ACL failures. Moreover, higher values of anterior subluxation were found among patients with repeated failure and those with a medial or lateral meniscal defect.

Preoperative laxity in ACL-deficient knees increases with posterior tibial slope and medial meniscal tears

PURPOSE

The aim of this study was to determine patient and anatomic factors that influence anteroposterior and rotational laxity in knees with ACL tears. Based on the findings of biomechanical studies, we hypothesized that static and dynamic anterior tibial translation (ATT) as well as positive pivot shift would increase with female gender, tibial slope, and meniscal tears.

METHODS

The authors prospectively collected preoperative data and intraoperative findings of 417 patients that underwent ACL reconstruction. The exclusion criteria were: revision ACL procedures (n = 53), other surgical antecedents (n = 27), prior osteotomies (n = 7) or concomitant ligament tears on the ipsilateral knee (n = 34), and history of ACL tears in the contralateral knee (n = 45), leaving a study cohort of 251 patients. Their preoperative anteroposterior knee laxity was assessed objectively using 'static' monopodal weight-bearing radiographs and 'dynamic' instrumented differential measurements of ATT. Rotational laxity was assessed subjectively using the pivot shift test.

RESULTS

Multivariable regression showed that static ATT increases only with tibial slope (β = 0.30; p < 0.001), but dynamic ATT increases with tibial slope (β = 0.19; p = 0.041), medial meniscal tears (β = 1.27; p = 0.007), complete ACL tears (β = 2.06; p < 0.001), and to decrease with age (β = - 0.09; p < 0.001). Multivariable regression also indicated that high-grade pivot shift decreases with age (OR 0.94; p < 0.001) and for women (OR 0.25; p < 0.001), and to be higher for knees with complete ACL tears (OR 3.04; p = 0.002) or medial meniscal tears (OR 2.28; p = 0.010).

CONCLUSION

Contrary to expectations based on biomechanical studies, static ATT was only affected by high posterior tibial slope, while dynamic ATT was affected by both high posterior tibial slopes and medial meniscal tears, but not by gender or lateral meniscal tears. Likewise, pivot shift was affected by gender and medial meniscal tears, but not lateral meniscal tears or posterior tibial slope. These findings are relevant to guide surgeons in optimizing their surgical procedures, such as conserving the menisci when possible, and rehabilitation protocols, by delaying full weight-bearing and return to sports in patients with anatomic and lesional risk factors.

LEVEL OF EVIDENCE

Cohort study, Level IV.

Automated, accurate, and three-dimensional method for calculating sagittal slope of the tibial plateau

Increased posterior-inferior directed slope of the subchondral bone of the lateral tibial plateau is a risk factor for noncontact rupture of the anterior cruciate ligament (ACL). Previous measures of lateral tibial slope, however, vary from study to study and often lack documentation of their accuracy. These factors impede identifying the magnitude of lateral tibial slope that increases risk of noncontact ACL rupture. Therefore, we developed and evaluated a new method that (1) requires minimal user input; (2) employs 3D renderings of the tibia that are referenced to a 3D anatomic coordinate system; and (3) is precise, reliable, and accurate. The user first isolated the proximal tibia from computed tomography (CT) scans. Then, the algorithm placed the proximal tibia in an automatically generated tibial coordinate system. Next, it identified points along the rim of subchondral bone around the lateral tibial plateau, iteratively fit a plane to this rim of points, and, finally, referenced the plane to the tibial coordinate system. Precision and reliability of the lateral slope measurements were respectively assessed via standard deviation and intra- and inter-class correlation coefficients using CT scans of three cadaveric tibia. Accuracy was quantified by comparing changes in lateral tibial slope calculated by our algorithm to predefined in silico changes in slope. Precision, reliability, and accuracy were ≤0.18°, ≥0.998, and ≤0.13°, respectively. We will use our novel method to better understand the relationship between lateral tibial slope and knee biomechanics towards preventing ACL rupture and improving its treatment.

Epidemiology of Recurrent Anterior Cruciate Ligament Injuries in National Collegiate Athletic Association Sports: The Injury Surveillance Program, 2004-2014

Background:

An anterior cruciate ligament (ACL) rupture is a serious injury that can be career-ending in collegiate athletics. A rerupture after primary ACL reconstruction occurs in 1% to 11% of all athletes.

Purpose:

To describe the epidemiology of recurrent ACL ruptures in the 25 National Collegiate Athletic Association (NCAA) sports in the NCAA Injury Surveillance Program (ISP) and to identify and compare sport-specific risk factors for a recurrent ACL rupture.

Study Design:

Descriptive epidemiology study.

Methods:

Athletes who experienced a primary or recurrent ACL rupture between 2004 and 2014 were identified using data from the NCAA ISP. ACL ruptures occurred in 12 of 25 sports during the study period. We assessed the rates and patterns of primary and recurrent ACL ruptures and reported them as events per 10,000 athlete-exposures (AEs). Sex-comparable sports were compared using rate ratios. Rupture rates were compared using odds ratios, with P values <.05 indicating significance. Regular-season and postseason data were combined because of low counts of postseason events.

Results:

Of 350,416 AEs, there were 1105 ACL ruptures, 126 of which were recurrent. The highest rates of recurrent ACL ruptures (per 10,000 AEs) were among male football players (15), female gymnasts (8.2), and female soccer players (5.2). Of sports played by athletes of both sexes, women’s soccer had a significantly higher rate of recurrent ACL ruptures than men’s soccer (rate ratio, 3.8 [95% CI, 1.3-15]). Among all sports, men had a significantly higher rate of recurrent ACL ruptures (4.3) than women (3.0) (P = .04). Overall, the ratio of recurrent to primary ACL ruptures decreased over the 10-year study period. Both women and men had a decreasing trend of recurrent to primary ACL ruptures, although women had a steeper decrease.

Conclusion:

These data can help identify athletes who are most at risk of recurrent ACL ruptures after ACL reconstruction and who may benefit from injury prevention programs.

The effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament reconstruction: An animal study

Objectives

To compare the effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament (ACL) reconstruction animal model.

Methods

Anterior cruciate ligament reconstruction using the plantaris tendon as graft material was performed on both knees of 24 rabbits (48 knees) to mimic ACL reconstruction by two different suspensory fixation devices for graft fixation. For the adjustable fixation device model (Socket group; group S), a 5 mm deep socket was created in the lateral femoral condyle (LFC) of the right knee. For the fixed-loop model (Tunnel group; group T), a femoral tunnel penetrating the LFC was created in the left knee. Animals were sacrificed at four and eight weeks after surgery for histological evaluation and biomechanical testing.

Results

Histologically, both groups showed a mixture of direct and indirect healing patterns at four weeks, whereas only indirect healing patterns were observed in both groups at eight weeks. No significant histological differences were seen between the two groups at four and eight weeks in the roof zone (four weeks, S: mean 4.8 sd 1.7, T: mean 4.5 sd 0.5, p = 0.14; eight weeks, S: mean 5.8 sd 0.8, T: mean 4.8 sd 1.8, p = 0.88, Mann-Whitney U test) or side zone (four weeks, S: mean 5.0 sd 1.2, T: mean 4.8 sd 0.4, p = 0.43; eight weeks, S: mean 5.3 sd 0.8,T: mean 5.5 sd 0.8, p = 0.61, Mann-Whitney U test) . Similarly, no significant difference was seen in the maximum failure load between group S and group T at four (15.6 sd 9.0N and 13.1 sd 5.6N) or eight weeks (12.6 sd 3.6N and 17.1 sd 6.4N, respectively).

Conclusion

Regardless of bone tunnel configuration, tendon-bone healing after ACL reconstruction primarily occurred through indirect healing. No significant histological or mechanical differences were observed between adjustable and fixed-loop femoral cortical suspension methods.

Cite this article: Y. Sato, R. Akagi, Y. Akatsu, Y. Matsuura, S. Takahashi, S. Yamaguchi, T. Enomoto, R. Nakagawa, H. Hoshi, T. Sasaki, S. Kimura, Y. Ogawa, A. Sadamasu, S. Ohtori, T. Sasho. The effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament reconstruction: An animal study. Bone Joint Res 2018;7:327–335. DOI: 10.1302/2046-3758.75.BJR-2017-0238.R2.

Comparison of pain behaviour and osteoarthritis progression between anterior cruciate ligament transection and osteochondral injury in rat models

Objectives

In this study, we compared the pain behaviour and osteoarthritis (OA) progression between anterior cruciate ligament transection (ACLT) and osteochondral injury in surgically-induced OA rat models.

Methods

OA was induced in the knee joints of male Wistar rats using transection of the ACL or induction of osteochondral injury. Changes in the percentage of high limb weight distribution (%HLWD) on the operated hind limb were used to determine the pain behaviour in these models. The development of OA was assessed and compared using a histological evaluation based on the Osteoarthritis Research Society International (OARSI) cartilage OA histopathology score.

Results

Both models showed an increase in joint pain as indicated by a significant (p < 0.05) decrease in the values of %HLWD at one week post-surgery. In the osteochondral injury model, the %HLWD returned to normal within three weeks, while in the ACLT model, a significant decrease in the %HLWD was persistent over an eight-week period. In addition, OA progression was more advanced in the ACLT model than in the osteochondral injury model. Furthermore, the ACLT model exhibited a higher mean OA score than that of the osteochondral injury model at 12 weeks.

Conclusion

The development of pain patterns in the ACLT and osteochondral injury models is different in that the OA progression was significant in the ACLT model. Although both can be used as models for a post-traumatic injury of the knee, the selection of appropriate models for OA in preclinical studies should be specified and relevant to the clinical scenario.

Cite this article: T. Tawonsawatruk, O. Sriwatananukulkit, W. Himakhun, W. Hemstapat. Comparison of pain behaviour and osteoarthritis progression between anterior cruciate ligament transection and osteochondral injury in rat models. Bone Joint Res 2018;7:244–251. DOI: 10.1302/2046-3758.73.BJR-2017-0121.R2.

Risk factors for progression of articular cartilage damage after anatomical anterior cruciate ligament reconstruction

Aims

To investigate the risk factors for progression of articular cartilage damage after anatomical anterior cruciate ligament (ACL) reconstruction.

Patients and Methods

A total of 174 patients who underwent second-look arthroscopic evaluation after anatomical ACL reconstruction were enrolled in this study. The graded condition of the articular cartilage at the time of ACL reconstruction was compared with that at second-look arthroscopy. Age, gender, body mass index (BMI), ACL reconstruction technique, meniscal conditions, and other variables were assessed by regression analysis as risk factors for progression of damage to the articular cartilage.

Results

In the medial compartment, multivariable logistic regression analysis indicated that partial medial meniscectomy (odds ratio (OR) 6.82, 95% confidence interval (CI) 2.11 to 22.04, p = 0.001), pivot-shift test grade at the final follow-up (OR 3.53, CI 1.39 to 8.96, p = 0.008), BMI (OR 1.15, CI 1.03 to 1.28, p = 0.015) and medial meniscal repair (OR 3.19, CI 1.24 to 8.21, p = 0.016) were significant risk factors for progression of cartilage damage. In the lateral compartment, partial lateral meniscectomy (OR 10.94, CI 4.14 to 28.92, p < 0.001) and side-to-side differences in anterior knee laxity at follow-up (OR 0.63, p = 0.001) were significant risk factors.

Conclusion

Partial meniscectomy was found to be strongly associated with the progression of articular cartilage damage despite r anatomical ACL reconstruction. Cite this article: Bone Joint J 2018;100-B:285–93.

Biological augmentation of graft healing in anterior cruciate ligament reconstruction: a systematic review

Aims

The success of anterior cruciate ligament reconstruction (ACLR) depends on osseointegration at the graft-tunnel interface and intra-articular ligamentization. Our aim was to conduct a systematic review of clinical and preclinical studies that evaluated biological augmentation of graft healing in ACLR.

Materials and Methods

In all, 1879 studies were identified across three databases. Following assessment against strict criteria, 112 studies were included (20 clinical studies; 92 animal studies).

Results

Seven categories of biological interventions were identified: growth factors, biomaterials, stem cells, gene therapy, autologous tissue, biophysical/environmental, and pharmaceuticals. The methodological quality of animal studies was moderate in 97%, but only 10% used clinically relevant outcome measures. The most interventions in clinical trials target the graft-tunnel interface and are applied intraoperatively. Platelet-rich plasma is the most studied intervention, but the clinical outcomes are mixed, and the methodological quality of studies was suboptimal. Other biological therapies investigated in clinical trials include: remnant-augmented ACLR; bone substitutes; calcium phosphate-hybridized grafts; extracorporeal shockwave therapy; and adult autologus non-cultivated stem cells.

Conclusion

There is extensive preclinical research supporting the use of biological therapies to augment ACLR. Further clinical studies that meet the minimum standards of reporting are required to determine whether emerging biological strategies will provide tangible benefits in patients undergoing ACLR. Cite this article: Bone Joint J 2018;100-B:271-84.