Knee ligament injury, surgery and osteoarthrosis. Truth or consequences?

Treatment for Acute Anterior Cruciate Ligament Tear in Young Active Adults

BACKGROUND: Anterior cruciate ligament (ACL) injury of the knee is common in young active adults and often has severe and sometimes lifelong consequences. The clinical management of this injury remains debated. A prior trial of early versus delayed optional ACL repair showed no differences in outcomes at 2 years. METHODS: We present the 11-year follow-up of a randomized clinical trial involving 121 young active adults (mean age 26yo, 74% male) with an acute sports-related ACL tear. We compared patient-reported and radiographic outcomes between those randomized to receive early ACL reconstruction (ACLR) followed by exercise therapy (N=62) and those treated with early exercise therapy plus optional delayed ACLR (N=59). The primary end point at 11 years was change from baseline in the mean of four subscales of the Knee Injury and Osteoarthritis Outcome Score (KOOS) — pain, symptoms, function in sports and recreation, and knee-related quality of life (KOOS4; range of scores, 0 [worst] to 100 [best]; minimal important change=9). RESULTS: In all, 88% of the cohort followed up at 11 years (53/62 in the early vs. 54/59 in the optional late ACL repair groups), and 52% of those assigned to optional delayed ACLR underwent ACLR. Mean improvement in KOOS4 from baseline to 11 years was 46 points for those assigned to early ACLR plus exercise therapy and 45 points for those assigned to exercise therapy plus optional delayed ACLR (between-group difference, 1.6 points; 95% confidence interval [CI], −8.8 to 5.6; P=0.67 after adjustment for baseline score, full analysis set). About two thirds of the full cohort reported meeting the case definition for a “patient-acceptable symptom state” (KOOS4 patient-acceptable symptom state threshold value=79), whereas 44% had developed radiographic osteoarthritis of their injured knee. Mean summed incident radiographic osteoarthritis feature scores, scores range from 0 to 30 where higher scores indicate more severe joint damage, were 2.4 for the group assigned to early ACLR and 1.0 for the group assigned to exercise therapy plus optional delayed ACLR (mean difference, 1.0; 95% CI, 0.1 to 1.9). CONCLUSIONS: At 11-year follow-up, among young active adults with acute ACL tears assigned to early ACLR plus exercise versus initial exercise therapy with the option of delayed ACLR, there were no differences in patient-reported outcomes. (Funded by the Swedish Research Council; ISRCTN number, ISRCTN84752559.)

Primary Proximal ACL Repair: A Biomechanical Evaluation of Different Arthroscopic Suture Configurations

Purpose: Several suture techniques have been described in the past for direct ACL repair with poor healing capacity and a high re-rupture rate. Therefore, we investigated a refixation technique for acute primary proximal ACL repair. The purpose of this study is to compare the biomechanical properties of different suture configurations using a knotless anchor. Methods: In this study, 35 fresh-frozen porcine knees underwent proximal ACL refixation. First, in 10 porcine femora, the biomechanical properties of the knotless anchor, without the ligament attached, were tested. Then, three different suture configurations were evaluated to reattach the remaining ACL. Using a material testing machine, the structural properties were evaluated for cyclic loading followed by loading to failure. Results: The ultimate failure load of the knotless anchor was 198, 76 N ± 23, 4 N significantly higher than all of the tested ACL suture configurations. Comparing the different configurations, the modified Kessler–Bunnell suture showed significant superior ultimate failure load, with 81, 2 N ± 15, 6 N compared to the twofold and single sutures (50, 5 N ± 14 N and 37, 5 ± 3, 8 N). In cyclic loading, there was no significant difference noted for the different configurations in terms of stiffness and elongation. Conclusions: The results of this in vitro study show that when performing ACL suture using a knotless anchor, a modified Kessler–Bunnell suture provides superior biomechanical properties than a single and a twofold suture. Within this construct, no failure at the bone–anchor interface was seen. Clinical relevance: Since primary suture repair techniques of ACL tears have been abandoned because of inconsistent results, ACL reconstruction remains the gold standard of treating ACL tears. However, with the latest improvements in surgical techniques, instrumentation, hardware and imaging, primary ACL suture repair might be a treatment option for a select group of patients. By establishing an arthroscopic technique in which proximal ACL avulsion can be reattached, the original ACL can be preserved by using a knotless anchor and a threefold suture configuration. Nevertheless, this technique provides an inferior ultimate failure load compared to graft techniques, so a careful rehabilitation program must be followed if using this technique in vivo.

Periostin regulation and cartilage degradation early after anterior cruciate ligament reconstruction

OBJECTIVE AND DESIGN

The purpose of this study was to explore pathological processes during the first 4 weeks after anterior cruciate ligament reconstruction (ACLR).

SUBJECTS

Sixteen ACL-injured patients (8 females/8 males, mean age = 19.1, mean BMI = 28.6).

METHODS

Arthrocentesis was performed 1 and 4 weeks after ACLR. Proteins in the synovial fluid were identified using nanoLC-ESI-MS/MS. Differentially up- or down-regulated proteins were identified and quantified, and a pathway analysis was performed. All identified proteins were mapped into a protein-protein interaction (PPI) network, and networks of PPIs with a combined score > 0.9 were then visualized.

RESULTS

Seven pathways were upregulated after ACLR: PI3K-AKT signaling pathway, extracellular matrix (ECM)-receptor interaction, focal adhesion, protein digestion and absorption, ameobiasis, and platelet activation. Network analyses identified 8 proteins that were differentially upregulated with strong PPI interactions (periostin and 7 collagen-related proteins). Increases in periostin moderately correlated with increases in a synovial fluid biomarker of type II cartilage degradation (ρ = 0.51, p = 0.06).

CONCLUSION

Pro-inflammatory pathways and periostin were upregulated after ACLR. Periostin demonstrated strong network connections with markers of collagen breakdown, and future work is needed to determine whether periostin may offer a biomarker of early cartilage degradation after ACLR and/or play an active role in early post-traumatic osteoarthritis (PTOA) progression.

Does meniscectomy have any advantage over conservative treatment in middle-aged patients with degenerative medial meniscus posterior root tear?

Background

The best treatment for degenerative medial meniscus posterior root tear (MMPRT) remains controversial. This study aimed to compare the clinical and radiological outcomes of arthroscopic meniscectomy and conservative treatment for degenerative MMPRT.

Methods

From January 2007 to December 2014, 146 patients (Meniscectomy group, 90; Conservative group, 56) were evaluated. Clinical outcomes were assessed using the Visual Analog Scale, International Knee Documentation Committee subjective scoring scale, Tegner activity scale, and Lysholm knee scoring scale at the final follow-up. Radiologic outcomes evaluated the progression of osteoarthritis (OA) according to the Kellgren-Lawrence (K-L) classification. We compared the hip-knee-ankle angle (HKAA), medial proximal tibial angle, tibial posterior slope angle, and width of medial joint space. After an average follow-up of 6.3 years, the survivorship was analyzed using the Kaplan–Meier method.

Results

All clinical outcomes were significantly improved in both groups after treatment, with no significant differences between the two groups at the final follow-up. The progression of OA according to the K-L classification, HKAA and width of medial joint space was significantly advanced in the meniscectomy group (p = 0.03, 0.04, 0.03, respectively). The 10-year survival rates in the meniscectomy and conservative groups were 87 and 88%, respectively.

Conclusions

This study demonstrated that both conservative treatment and meniscectomy provided symptomatic relief. However, it was confirmed that OA progression was more severe in the meniscectomy. We conclude that arthroscopic meniscectomy had no advantage over conservative treatment in terms of clinical outcomes and OA progression in middle-aged patients with MMPRT.

Level of evidence

Level III; retrospective comparative study.

Successful treatment of degenerative medial meniscal tears in well-aligned knees with fibrin clot implantation

PURPOSE

The purpose of this study was to examine the results of meniscal repair performed for symptomatic degenerative medial meniscal tears.

METHODS

Twenty-four knees in 24 patients with symptomatic degenerative medial meniscal tears (mostly complex horizontal tears) who underwent isolated arthroscopic repair combined with autologous fibrin clot implantation were included in this study. The patients were followed up for a minimum of 2 years. The overall clinical outcome was evaluated using the Lysholm score, while the activity level was graded on the Tegner Activity Scale. The assessment of healing status at the repair site was based on clinical signs/symptoms and follow-up MRI examination results. In addition, the effects of the patient's clinical and radiological factors on healing of the repaired menisci were analyzed.

RESULTS

The mean age of the study subjects was 47.0 ± 8.1 years with a mean follow-up period of 39.3 ± 11.6 months. The Lysholm score significantly improved after surgery (P < 0.01). During the follow-up period, meniscal repairs were deemed to have failed in 6 of the 24 knees (25%). In the analysis of factors influencing meniscal healing, varus deformity (% of mechanical axis < 30%) was identified in all knees in the repair failure group, and the presence of varus deformity was shown to be a significant risk factor correlated with repair failure, while other factors did not significantly influence the healing status.

CONCLUSIONS

The short-term follow-up results showed that arthroscopic repair of degenerative medial meniscal tears combined with fibrin clot implantation attained clinical healing in 18 of 24 knees (75%) of patients, while 6 of the 24 knees (25%) of patients experienced clinical failure. The presence of varus deformity negatively affects the healing rate. In well-aligned knees, degenerative medial meniscal tears are successfully treated by isolated repair with fibrin clot implantation.

LEVEL OF EVIDENCE

IV.

Dysregulated Inflammatory Response Related to Cartilage Degradation after ACL Injury

PURPOSE

Elevated synovial fluid (SF) concentrations of proinflammatory cytokines, degradative enzymes, and cartilage breakdown markers at the time of anterior cruciate ligament (ACL) reconstruction are associated with worse postoperative patient-reported outcomes and cartilage quality. However, it remains unclear if this is due to a more robust or dysregulated inflammatory response or is a function of a more severe injury. The objective of this study was to evaluate the association of the molecular composition of the SF, patient demographics, and injury characteristics to cartilage degradation after acute ACL injury.

METHODS

We performed a cluster analysis of SF concentrations of proinflammatory and anti-inflammatory cytokines, and biomarkers of cartilage degradation, bony remodeling, and hemarthrosis. We evaluated the association of biomarker clusters with patient demographics, days between injury, Visual Analogue Scale pain, SF aspirate volumes, and bone bruise volumes measured on magnetic resonance imaging.

RESULTS

Two clusters were identified from the 35 patients included in this analysis, dysregulated inflammation and low inflammation. The dysregulated inflammation cluster consisted of 10 patients and demonstrated significantly greater concentrations of biomarkers of cartilage degradation (P < 0.05) as well as a lower ratio of anti-inflammatory to proinflammatory cytokines (P = 0.053) when compared with the low inflammation cluster. Patient demographics, bone bruise volumes, SF aspirate volumes, pain, and concomitant injuries did not differ between clusters.

CONCLUSIONS

A subset of patients exhibited dysregulation of the inflammatory response after acute ACL injury which may increase the risk of posttraumatic osteoarthritis. This response does not appear to be a function of injury severity.

Single-leg hop mechanics are correlated with self-reported knee function early after anterior cruciate ligament reconstruction

BACKGROUND

Biomechanical changes that persist after anterior cruciate ligament (ACL) injury may impact short- and long-term outcomes. Understanding the relationship of biomechanics during a dynamic task and patient reported function can better identify patients who are most vulnerable to sub-optimal long-term outcomes, such as osteoarthritis (OA). The purpose of this study was to determine whether hip and knee biomechanics during single-leg hop landing were significantly correlated with the Knee injury and Osteoarthritis Outcome Score (KOOS), and whether symptomatic knees displayed altered biomechanics relative to asymptomatic knees.

METHODS

Hip and knee biomechanics during the landing phase of a single-leg hop of thirty subjects with ACLR were analyzed. Subjects were also classified as symptomatic or asymptomatic based on their KOOS results. Correlation analyses and group comparisons between symptomatic and asymptomatic subjects were conducted.

FINDINGS

KOOS Symptoms, Pain, and Sport subscales were significantly correlated with frontal and sagittal plane hip and knee biomechanics. Furthermore, those with symptomatic knees demonstrated greater hip and knee flexion angles, and greater hip flexion moments.

INTERPRETATION

These results indicate that biomechanics associated with ACLR during a single-leg hop are correlated with worse KOOS outcomes. However, these correlations may be due to symptoms of the recovery from ACLR rather than those of OA. The results of this study may help to identify rehabilitation opportunities for patients at risk for worse long-term outcomes after ACLR.

Increased rates of knee arthroplasty and cost of patients with meniscal tears treated with arthroscopic partial meniscectomy versus non-operative management

PURPOSE

The purpose of this study was to determine the cost of arthroscopic partial meniscectomy (APM), one of the most common surgeries performed by orthopaedic surgeons, and the associated rate of progression to knee arthroplasty (KA) compared to patients treated non-operatively after diagnosis of meniscal tear.

METHODS

Utilizing data mining software (PearlDiver, Colorado Springs, CO), a national insurance database of approximately 23.5 million orthopaedic patients was queried for patients diagnosed with a meniscal tear. Patients were classified by treatment: non-operative and arthroscopic partial meniscectomy and were followed after initial diagnosis for cost and progression to knee arthroplasty.

RESULTS

There were 176,407 subjects in the non-op group and 114,194 subjects in the arthroscopic partial meniscectomy group. Arthroscopic partial meniscectomy generated more cost than non-operative ($3842.57 versus $411.05, P < 0.001). Arthroscopic partial meniscectomy demonstrated greater propensity to need future knee arthroplasty (11.4% at 676 days) than those treated non-operatively (9.5% at 402 days) (P < 0.001). Female patients demonstrated a higher rate of progression to knee arthroplasty in the arthroscopic partial meniscectomy and non-operative groups (P < 0.001).

CONCLUSION

Compared to non-operative treatment for meniscal tears, arthroscopic partial meniscectomy is more expensive and does not appear to decrease the rate of progression to knee arthroplasty. Patients undergoing arthroscopic partial meniscectomy yielded on average a delay of only 9 months (274 days) before undergoing knee arthroplasty. Female patients experienced a significantly higher rate of progression to knee arthroplasty. The authors recognize the limitations of this type of study including its retrospective nature, reliance upon accurate coding and billing information, and the inability to determine whether symptoms including mechanical locking played a role in the decision to perform an APM.

LEVEL OF EVIDENCE

IV.

Development of the KOOSglobal Platform to Measure Patient-Reported Outcomes After Anterior Cruciate Ligament Reconstruction

BACKGROUND

The Knee injury and Osteoarthritis Outcome Score (KOOS) has demonstrated inferior psychometric properties when compared with the International Knee Documentation Committee (IKDC) subjective knee form when assessing outcomes after anterior cruciate ligament (ACL) reconstruction. The KOOS, Joint Replacement (KOOS, JR) is a validated short-form instrument to assess patient-reported outcomes (PROs) after knee arthroplasty, and the purpose of this study was to determine if augmenting the KOOS, JR with additional KOOS items would allow for the creation of a short-form KOOS-based global knee score for patients undergoing ACL reconstruction, with psychometric properties similar to those of the IKDC.

HYPOTHESIS

An augmented version of the KOOS, JR could be created that would demonstrate convergent validity with the IKDC but avoid the ceiling effects and limitations previously noted with several of the KOOS subscales.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Based on preoperative and 2-year postoperative responses to the KOOS questionnaires from a sample of 1904 patients undergoing ACL reconstruction, an aggregate score combining the KOOS, JR and the 4 KOOS Quality of Life subscale questions, termed the KOOS_global, was developed. Psychometric properties of the KOOS_global were then compared with those of the IKDC subjective score. Convergent validity between the KOOS_global and IKDC was assessed with a Spearman correlation (ρ). Responsiveness of the 2 instruments was assessed by calculating the pre- to postoperative effect size and relative efficiency. Finally, the presence of a preoperative floor or postoperative ceiling effect was defined with the threshold of 15% of patients reporting either the worst possible (0 for KOOS_global and IKDC) or the best possible (100 for KOOS_global and IKDC) scores, respectively.

RESULTS

The newly developed KOOS_global was responsive after ACL reconstruction and demonstrated convergent validity with the IKDC. The KOOS_global significantly correlated with the IKDC scores (ρ = 0.91, P < .001), explained 83% of the variability in IKDC scores, and was similarly responsive (relative efficiency = 0.63). While there was a higher rate of perfect postoperative scores with the KOOS_global (213 of 1904, 11%) than with the IKDC (6%), the KOOS_global was still below the 15% ceiling effect threshold.

CONCLUSION

The large ceiling effects limit the ability to use several of the KOOS subscales with the younger, more active ACL population. However, by creating an aggregate score from the KOOS, JR and 4 KOOS Quality of Life subscale questions, the 11-item KOOS_global offers a responsive PRO tool after ACL reconstruction that converges with the information captured with the IKDC. Also, by offering the ability to calculate multiple scores from a single questionnaire, the KOOS_global may provide the orthopaedic community a single PRO platform to be used across knee-related subspecialties. Registration: NCT00478894 ( ClinicalTrials.gov identifier).

Select Biomarkers on the Day of Anterior Cruciate Ligament Reconstruction Predict Poor Patient-Reported Outcomes at 2-Year Follow-Up: A Pilot Study

Background

The majority of patients develop posttraumatic osteoarthritis within 15 years of anterior cruciate ligament (ACL) injury. Inflammatory and chondrodegenerative biomarkers have been associated with both pain and the progression of osteoarthritis; however, it remains unclear if preoperative biomarkers differ for patients with inferior postoperative outcomes.

Hypothesis/Purpose

The purpose of this pilot study was to compare biomarkers collected on the day of ACL reconstruction between patients with “good” or “poor” 2-year postoperative outcomes. We hypothesized that inflammatory cytokines and chondrodegenerative biomarker concentrations would be significantly greater in patients with poorer outcomes.

Study Design

Prospective cohort design.

Methods

22 patients (9 females, 13 males; age = 19.5 ± 4.1 years; BMI = 24.1 ± 3.6 kg/m²) previously enrolled in a randomized trial evaluating early anti-inflammatory treatment after ACL injury. Biomarkers of chondrodegeneration and inflammation were assessed from synovial fluid (sf) samples collected on the day of ACL reconstruction. Participants completed Knee Injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) questionnaires two years following surgery. Patients were then categorized based on whether their KOOS Quality of Life (QOL) score surpassed the Patient Acceptable Symptom State (PASS) threshold of 62.5 points or the IKDC PASS threshold of 75.9 points.

Results

Patients that failed to reach the QOL PASS threshold after surgery (n = 6, 27%) had significantly greater sf interleukin-1 alpha (IL-1α; p = 0.004), IL-1 receptor antagonist (IL-1ra; p = 0.03), and matrix metalloproteinase-9 (MMP-9; p = 0.01) concentrations on the day of surgery. Patients that failed to reach the IKDC PASS threshold (n = 9, 41%) had significantly greater sf IL-1α (p = 0.02).

Conclusion

These pilot data suggest that initial biochemical changes after injury may be an indicator of poor outcomes that are not mitigated by surgical stabilization alone. Biological adjuvant treatment in addition to ACL reconstruction may be beneficial; however, these data should be used for hypothesis generation and more definitive randomized clinical trials are necessary.

Analysis of change in gait in the ovine stifle: normal, injured, and anterior cruciate ligament reconstructed

Background

Many patients who undergo anterior cruciate ligament (ACL) reconstructive surgery develop post-traumatic osteoarthritis (PTOA). ACL reconstructive surgery may not fully restore pre-injury joint biomechanics, thereby resulting in further joint damage and contributing to the development of PTOA. In an ovine model of idealized ACL reconstruction (ACL-R), it has been shown that signs of PTOA develop within surgical joints by 20 weeks post-surgery. The aim of the present study was to investigate whether altered kinematics contribute to early PTOA development within ACL-R joints of the ovine injury model by comparing the gait of these surgical animals to the gait of a stable normal control group, and an unstable injury group in which the ACL and medial collateral ligament (MCL) had been transected.

Methods

Fifteen skeletally mature female sheep were allocated evenly into 3 treatment groups: normal control, ACL-R, and ACL/MCL Tx (each group n = 5). Each animal’s gait was recorded at baseline, 4 weeks post injury, and 20 weeks post injury. Principal component analysis (PCA) was used to identify the kinematic patterns that may be discriminant between treatment groups. Results from previous studies were referenced to present the amount of gross PTOA-like changes that occurred in the joints.

Results

ACL-R and ACL/MCL transected (Tx) animals developed a similar amount of early PTOA-like changes within the surgical joints, but differed significantly in the amount of kinematic change present at 20 weeks post-surgery. We showed that the stifle joint kinematics of ACL/MCL Tx differed significantly from those of CTRL and the majority of ACL-R animals, while no significant differences in joint kinematic changes were found between ACL-R and CTRL animals.

Conclusions

These results suggest that the early PTOA-like changes reported in the ACL-R model cannot be attributed exclusively to post-surgical kinematic changes, and therefore biologic components in the post-injury environment must be contributing significantly to PTOA development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1576-3) contains supplementary material, which is available to authorized users.

Delaying ACL reconstruction and treating with exercise therapy alone may alter prognostic factors for 5-year outcome: an exploratory analysis of the KANON trial

Aim

Identify injury-related, patient-reported and treatment-related prognostic factors for 5-year outcomes in acutely ACL-ruptured individuals managed with early reconstruction plus exercise therapy, exercise therapy plus delayed reconstruction or exercise therapy alone.

Methods

Exploratory analysis of the Knee Anterior Cruciate Ligament, Nonsurgical versus Surgical Treatment (KANON) trial (ISRCTN84752559). Relationships between prognostic factors (baseline cartilage, meniscus and osteochondral damage, baseline extension deficit, baseline patient-reported outcomes, number of rehabilitation visits, graft/contralateral ACL rupture, non-ACL surgery and ACL treatment strategy) and 5-year Knee Injury and Osteoarthritis Outcome Score (KOOS) pain, symptoms, sport/recreation and quality of life (QOL) scores were explored using multivariable linear regression. Estimates were adjusted for sex, age, body mass index, preinjury activity level, education and smoking.

Results

For all participants (n=118), graft/contralateral ACL rupture, non-ACL surgery and worse baseline 36-item Short-Form Mental Component Scores were associated with worse outcomes. Treatment with exercise therapy alone was a prognostic factor for less knee symptoms compared with early reconstruction plus exercise therapy (regression coefficient 10.1, 95% CI 2.3 to 17.9). Baseline meniscus lesion was associated with worse sport/recreation function (−14.4, 95% CI −27.6 to –1.3) and osteochondral lesions were associated with worse QOL (−12.3, 95% CI −24.3 to –0.4) following early reconstruction plus exercise therapy. In the same group, undergoing additional non-ACL surgery and worse baseline KOOS scores were prognostic for worse outcome on all KOOS subscales. Following delayed reconstruction, baseline meniscus damage was a prognostic factor for less pain (14.3, 95% CI 0.7 to 27.9). Following exercise therapy alone, undergoing non-ACL surgery was prognostic for worse pain.

Conclusions

Treatment-dependent differences in prognostic factors for 5-year outcomes may support individualised treatment after acute ACL rupture in young active individuals.

Trial registration number

Current Controlled Trials ISRCTN84752559.

A Multicenter Study of Early Anti-inflammatory Treatment in Patients With Acute Anterior Cruciate Ligament Tear

BACKGROUND

It is increasingly recognized that biochemical abnormalities of the joint precede radiographic abnormalities of posttraumatic osteoarthritis (PTOA) by as much as decades. A growing body of evidence strongly suggests that the progression from anterior cruciate ligament (ACL) injury to PTOA is multifactorial, involving the interplay between biomechanical disturbances and biochemical homeostasis of articular cartilage.

PURPOSE

The purposes of this randomized study using an acute ACL injury model were to (1) evaluate the natural progression of inflammatory and chondrodegenerative biomarkers, (2) evaluate the relationship between subjective reports of pain and inflammatory and chondrodegenerative biomarkers, and (3) determine if postinjury arthrocentesis and corticosteroid injection offer the ability to alter this biochemical cascade.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

A total of 49 patients were randomized to 4 groups: group 1 (corticosteroid at 4 days after ACL injury, placebo injection of saline at 2 weeks), group 2 (placebo at 4 days after ACL injury, corticosteroid at 2 weeks), group 3 (corticosteroid at both time intervals), or a placebo group (saline injections at both time intervals). Patient-reported outcome measures and synovial biomarkers were collected at approximately 4 days, 11 days, and 5 weeks after injury. The change between the time points was assessed for all variables using Wilcoxon tests, and the relationship between changes in outcome scores and biomarkers were assessed by calculating Spearman ρ. Outcomes and biomarkers were also compared between the 4 groups using Kruskal-Wallis tests.

RESULTS

No adverse events or infections were observed in any study patients. With the exception of matrix metalloproteinase 1 (MMP-1) and tumor necrosis factor-inducible gene 6 (TSG-6), chondrodegenerative markers worsened over the first 5 weeks while all patient-reported outcomes improved during this time, regardless of treatment group. Patient-reported outcomes did not differ between patients receiving corticosteroid injections and the placebo group. However, increases in C-telopeptide of type II collagen (CTX-II), associated with collagen type II breakdown, were significantly greater in the placebo group (1.32 ± 1.10 ng/mL) than in either of the groups that received the corticosteroid injection within the first several days after injury (group 1: 0.23 ± 0.27 ng/mL [ P = .01]; group 3: 0.19 ± 0.34 ng/mL [ P = .01]).

CONCLUSION

PTOA begins at the time of injury and results early on in dramatic matrix changes in the knee. However, it is encouraging that early intervention with an anti-inflammatory agent was able to affect biomarkers of chondral degeneration. Should early intervention lead to meaningful changes in either the onset or severity of symptomatic PTOA, the current treatment paradigm for patients with ACL injury may have to be restructured to include early aspiration and intra-articular intervention.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01692756.

Projecting Lifetime Risk of Symptomatic Knee Osteoarthritis and Total Knee Replacement in Individuals Sustaining a Complete Anterior Cruciate Ligament Tear in Early Adulthood

OBJECTIVE

To estimate the lifetime risk of knee osteoarthritis (OA) and total knee replacement (TKR) in persons sustaining anterior cruciate ligament (ACL) tear by age 25 years.

METHODS

We used the Osteoarthritis Policy Model to project the cumulative incidence of symptomatic knee OA requiring TKR in varying situations: no prevalent or incident injury; isolated ACL tear, surgically treated; isolated ACL tear, nonoperatively treated; or a prevalent history or surgically treated ACL and meniscal tear (MT). We estimated MT prevalence and incidence and increased risk of knee OA associated with ACL injury and MT from published literature. We conducted a range of sensitivity analyses to examine the impact of uncertainty in input parameters.

RESULTS

Estimated lifetime risk of symptomatic knee OA was 34% for the cohort with ACL injury and MT, compared to 14% for the no-injury cohort. ACL injury without MT was associated with a lifetime risk of knee OA between 16% and 17%, depending on ACL treatment modality. Estimated lifetime risk of TKR ranged from 6% in the no-injury cohort to 22% for the ACL injury and MT cohort. Subjects in the ACL injury and MT cohort developed OA approximately 1.5 years earlier (55.7 versus 57.1) and underwent TKR approximately 2 years earlier (66 versus 68) than the cohort without knee injuries.

CONCLUSION

Sustaining ACL injury early in adulthood leads to greater lifetime risk and earlier onset of knee OA and TKR; concomitant MTs compound this risk. These data provide insight into the impact of sustainable injury prevention interventions in young adults.

Articular cartilage degeneration following anterior cruciate ligament injury: a comparison of surgical transection and noninvasive rupture as preclinical models of post-traumatic osteoarthritis

OBJECTIVE

Post-traumatic osteoarthritis (PTOA) is commonly studied using animal models. Surgical ACL transection is an established model, but noninvasive models may mimic human injury more closely. The purpose of this study was to quantify and compare changes in 3D articular cartilage (AC) morphology following noninvasive ACL rupture and surgical ACL transection.

METHODS

Thirty-six rats were randomized to uninjured control, noninvasive ACL rupture (Rupture), and surgical ACL transection (Transection), and 4 and 10 week time points (n = 6 per group). Contrast-enhanced micro-computed tomography (CE-μCT) was employed for AC imaging. Femoral and tibial AC were segmented and converted into thickness maps. Compartmental and sub-compartmental AC thickness and surface roughness (S_a) were computed. OARSI histologic scoring was performed.

RESULTS

In both injury groups, zones of adjacent thickening and thinning were evident on the medial femoral condyle, along with general thickening and roughening of femoral and tibial AC. The posterior tibia exhibited drastic thickening and surface degeneration, and this was worse in Transection. Both injury groups had increased AC thickness and S_a compared to Control at both time points, and Transection exhibited significantly higher S_a in every tibial compartment compared to Rupture. Histologic score was elevated in both groups, and the medial femur exhibited the most severe histologic degeneration.

CONCLUSIONS

This is the first 3D quantification of preclinical AC remodeling after ACL injury. Both injury models induced similar changes in AC morphology, but Transection exhibited higher tibial S_a and a greater degree of posterior tibial degeneration. We conclude that AC degeneration is a time-, compartment-, and injury-dependent cascade.

No difference in osteoarthritis after surgical and non-surgical treatment of ACL-injured knees after 10 years

PURPOSE

Aim of this study was to record and compare the functional and activity level as well as the manifestations of osteoarthritis after isolated ACL ruptures between patients with conservative treatment and ACL reconstruction with hamstrings tendon graft.

METHODS

Thirty-two patients diagnosed with ACL rupture were recorded. Clinical examination included the Tegner and Lysholm activity scale, the International Knee Documentation Committee Subjective Form and KT-1000 arthrometer. Narrowing of the medial and lateral joint spaces was assessed using the IKDC knee examination score.

RESULTS

Median follow-up was 10.3 years (range 10-11). Fifteen patients were conservatively treated (median age 33 years, range 25-39). Seventeen patients were operated (median age 31 years, range 20-36). There was significant difference between the mean values of IKDC scores in favour of the ACL-reconstruction group of patients, 86.8 (SD 6.5) versus 77.5 (SD 13.8), respectively (p = 0.04). The mean value of anteroposterior tibial translation was 1.5 mm (SD 0.2) for ACL-reconstruction group of patients, while the corresponding mean value for ACL-conservative group was 4.5 mm (SD 0.5), p = 0.03. Four patients in ACL-reconstruction group had radiological findings of grade C or D according to IKDC form. In ACL-conservative group, five patients presented similar signs (n.s.).

CONCLUSIONS

ACL reconstruction using hamstrings autograft resulted in better functional outcome and laxity measurements than ACL-conservative management. However, the incidence of radiological osteoarthritis was similar between the two groups and independent on the pre-operative grade of laxity and functional status of the patients. Equally, bone bruises were not found as a risk factor for the development of osteoarthritis after ACL rupture.

LEVEL OF EVIDENCE

Prospective randomized study, Level II.

Relationship between synovial fluid biomarkers of articular cartilage metabolism and the patient's perspective of outcome depends on the severity of articular cartilage damage following ACL trauma

Anterior cruciate ligament (ACL) trauma often occurs in combination with injury to the articular cartilage of the knee, this can result in earlier radiographic evidence of post traumatic osteoarthritis (OA) of the knee compared to the contralateral, ACL intact knee; however, the biomechanical and biological mechanisms associated with the onset and progression of this disease are not understood. We sought to gain insight into the mechanisms by determining the relationship between articular cartilage injury associated with ACL trauma and the expression of synovial fluid biomarkers of articular cartilage metabolism, and to evaluate the relationship between these biomarkers and the patient's perspective of the outcomes. Synovial fluid samples were acquired from 39 ACL injured subjects at an average of 10 weeks after injury, and 32 control subjects with normal knees (documented with clinical exam and MRI assessment). Subjects in the ACL-injured group were classified as low-risk for future OA if they displayed an International Cartilage Repair Society (ICRS) Grade 2 articular cartilage lesion or less and high-risk for future OA if they had an ICRS Grade 3A articular cartilage lesion. The patient's perspective of the injury was evaluated with the Knee Injury and Osteoarthritis Outcomes Score (KOOS). There were no significant differences in mean concentrations of the markers of type II collagen metabolism (CPII, C2C, and C1,2C) or the aggrecan breakdown Alanine-Arginine-Glycine-Serine (ARGS) -fragment between control subjects and the subjects in the low- and high-risk groups (p-value range: 0.80-0.43). Associations between ARGS-aggrecan concentration and KOOS subscales of symptoms and pain were significantly different between the low- and high-risk groups (p = 0.03 and p = 0.01, respectively). Likewise, there was strong evidence in support of an association between the markers of type II collagen metabolism (C1,2C and CPII concentrations) and the KOOS subscale of pain between the low- and high-risk groups (p = 0.051 and 0.077, correspondingly). In ACL injured subjects with concomitant Grade 3A articular cartilage injuries, concentrations of synovial fluid ARGS-aggrecan were directly associated with improvements in KOOS symptoms and pain. These findings suggest the possible involvement of ARGS-aggrecan in a localized tissue repair response involving an increase in aggrecan turnover following severe knee trauma. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:820-827, 2016.

Subchondral and epiphyseal bone remodeling following surgical transection and noninvasive rupture of the anterior cruciate ligament as models of post-traumatic osteoarthritis

OBJECTIVE

Animal models are frequently used to study post-traumatic osteoarthritis (PTOA). A common anterior cruciate ligament (ACL) injury model is surgical transection, which may introduce confounding factors from surgery. Noninvasive models could model human injury more closely. The purpose of this study was to compare subchondral and epiphyseal trabecular bone remodeling after surgical transection and noninvasive rupture of the ACL.

METHODS

Thirty-six rats were randomized to an uninjured control, surgical transection (Transection), or noninvasive rupture (Rupture). Animals were randomized to 4 or 10 week time points (n = 6 per group). Micro computed tomography (μCT) imaging was performed with an isotropic voxel size of 12 μm. Subchondral and epiphyseal bone was segmented semi-automatically, and morphometric analysis was performed.

RESULTS

Transection caused a greater decrease in subchondral bone volume fraction (BV/TV) than Rupture in the femur and tibia. Rupture had greater subchondral bone tissue mineral density (TMD) at 4 and 10 weeks in the femur and tibia. Subchondral bone thickness (SCB.Th) was decreased in the femur in Transection only. Epiphyseal BV/TV was decreased in Transection only, and Rupture exhibited increased femoral epiphyseal TMD compared to both Control and Transection. Rupture exhibited greater femoral epiphyseal trabecular thickness (Tb.Th.) compared to Control and Transection at 4 weeks, and both Rupture and Transection had increased femoral epiphyseal Tb.Th. at 10 weeks. Epiphyseal trabecular number (Tb.N) was decreased in both injury groups at both time points. Femoral and tibial epiphyseal structure model index (SMI) increased in both groups.

CONCLUSIONS

The two injury models cause differences in post-injury bone morphometry, and surgical transection may be introducing confounding factors that affect downstream bony remodeling.

Differences in hip-knee joint coupling during gait after anterior cruciate ligament reconstruction

BACKGROUND

After anterior cruciate ligament injury, patients have increased risk for developing degenerative osteoarthritis, potentially due to the kinematic changes that persist after surgical reconstruction. Current research only describes single joint kinematic differences rather than the way in which two joints behave concurrently, termed joint coupling. The purpose of this study was to compare knee motion relative to hip motion in anterior cruciate ligament reconstructed and healthy limbs during walking and jogging.

METHODS

Thirty-seven recreationally active volunteers (22 reconstructed, 15 healthy) walked and jogged at 4.83 km/h and 9.66 km/h respectively. Vector coding methods were used to calculate stride-to-stride variability, magnitude, and vector angle of 6 joint couples during walking and jogging: hip frontal-knee frontal planes, hip frontal-knee sagittal, hip frontal-knee transverse, hip sagittal-knee frontal, hip sagittal-knee transverse, and hip transverse-knee frontal planes.

FINDINGS

The hip sagittal-knee frontal and hip sagittal-knee transverse joint couples had decreased variability during mid-stance, and all other couples had increased variability during the stance phase in the reconstructed group. The reconstructed group had decreased magnitude of joint excursion in the hip frontal-knee sagittal couple during all phases of gait during walking. Vector angles of the hip frontal-knee transverse couple increased in the reconstructed group during the loading, middle, and terminal stance phases, and swing phase of gait during walking.

INTERPRETATION

The increased variability and decreased magnitude of joint excursion indicate that movement patterns were less consistent during walking gait despite employing a more constrained system during movement in the reconstructed limb compared to healthy controls.

Increased Lateral Tibial Slope Is a Risk Factor for Pediatric Anterior Cruciate Ligament Injury: An MRI-Based Case-Control Study of 152 Patients

BACKGROUND

Increased posterior tibial slope is associated with increased risk of anterior cruciate ligament (ACL) injury in adults. A similar association has not been rigorously examined in children and adolescents.

PURPOSE

To determine whether alterations in posterior tibial slope are associated with ACL tears in pediatric and adolescent patients and to quantify changes in tibial slope by age.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Magnetic resonance imaging (MRI) studies of the knee were reviewed by 3 raters blinded to each other in a 1:1 sample of cases and age- and sex-matched controls. A total of 76 skeletally immature ACL-injured knees were compared with 76 knees without ACL injury; the mean age of the study population was 14.8 ± 1.3 years. The posterior slope of the articular surface of the medial tibial plateau and lateral tibial plateau was measured by use of a method similar to that used in previous studies in adult populations. The current study technique differed in that the slope was measured on the cartilage surface, not the subchondral bone. Comparisons between knees were made with t tests, and Spearman correlation analysis was used to assess changes in tibial slope with advancing age.

RESULTS

Increased slope of the lateral tibial plateau (LTS) was significantly increased in ACL-injured patients compared with controls (5.7° ± 2.4° vs 3.4° ± 1.7°; P < .001). There was no statistically significant difference in the slope of the medial tibial plateau (MTS) in the ACL-injured and control knees (5.4° ± 2.2° vs 5.1° ± 2.3°; P = .42). There was no difference in LTS between male and female patients (4.46° vs 4.58°; P = .75). Receiver operating characteristic (ROC) analysis of the LTS revealed that a posterior tibial slope cutoff of >4° resulted in a sensitivity of 76% and a specificity of 75% for predicting ACL tears in this cohort. Spearman correlation analysis revealed that MTS and LTS decreased, or flattened, by 0.31° (P = .028, correlation coefficient r = -0.18) and 0.37° (P = .009, correlation coefficient r = -0.21) per year, respectively, as adolescents age.

CONCLUSION

The LTS was significantly associated with an increased risk of ACL injury in pediatric and adolescent patients. The MTS was not associated with risk of injury. Posterior slope was found to decrease, or flatten, with age. A cutoff of >4° for the posterior slope of the lateral compartment is 76% sensitive and 75% specific for predicting ACL injury in this cohort. The LTS did not influence the incidence of ACL injury differently between sexes.

Mechanisms of post-traumatic osteoarthritis after ACL injury

Anterior cruciate ligament (ACL) rupture is a common and devastating injury with long-term sequelae that include meniscal tears, chondral injury, and an increased risk of knee osteoarthritis (OA). ACL reconstruction is recommended to protect against knee instability, reduce the likelihood of meniscal tears and further surgery, and enable earlier return to sporting activities. ACL reconstruction, however, does not reduce the incidence of early-onset OA. In this review, we discuss the factors before and after surgery that are believed to contribute to the premature development of degenerative joint disease.

Increased risk for radiographic osteoarthritis features in young active athletes: a cross-sectional matched case-control study

OBJECTIVE

Prevalence data on radiographic osteoarthritis (ROA) in young active athletes is sparse. Aim was to assess in a matched case-control design the frequency of ROA in an athlete population and whether athlete status, gender, previous anterior cruciate ligament (ACL) surgery and age increase the odds for ROA.

DESIGN

135 consecutive athletes (82% soccer players) 18-36 years old and 550 non-athletes aged-matched controls had knee radiography (Lyon-Schuss protocol) for assessment of subacute or chronic knee complaints. Patients with acute trauma or fractures were excluded. Radiographs were graded according to the Kellgren-Lawrence and OARSI grading schemes. In addition, medial and lateral intercondylar notch osteophytes were scored. We used logistic regression model to assess the association of ROA and specific radiographic OA features with athlete status, prior ACL surgery, gender and age, adjusting for each other.

RESULTS

19.4% of patients were 18-22 years old, 26.4% were 23-27, 22.6% were 28-32, and 31.5% were 33-36 years old. 18.7% were female and 8.8% had previous ACL surgery. 8.5% had ROA and 6.0% had evidence of JSN. The adjusted odds ratios (aOR) for ROA were 2.8 (95% confidence interval 1.4, 5.5) for athletes, 7.0 (3.5, 13.9) for previous ACL surgery and 3.3 (1.2, 9.0) for age range 32-36. Athlete status significantly increased odds for tibiofemoral osteophytes [aOR 2.9 (1.6, 5.4)] and comparably for notch osteophytes [aOR 2.3 (1.1, 4.7)].

CONCLUSIONS

Athlete status, higher age and previous ACL surgery increase the risk of ROA with surgery being the strongest risk factor.

Frontal plane knee mechanics and medial cartilage MR relaxation times in individuals with ACL reconstruction: A pilot study

BACKGROUND

The objective of this pilot study was to evaluate cartilage T1ρ and T2 relaxation times and knee mechanics during walking and drop-landing for individuals with anterior cruciate ligament reconstruction (ACL-R).

METHODS

Nine patients (6 men and 3 women, age 35.8 ± 5.4 years, BMI 23.5 ± 2.5 kg/m(2)) participated 1.5 ± 0.8 years after single-bundle two-tunnel ACL reconstruction. Peak knee adduction moment (KAM), flexion moment (KFM), extension moment (KEM), and peak varus were calculated from kinematic and kinetic data obtained during walking and drop-landing tasks. T1ρ and T2 times were calculated for medial femur (MF), and medial tibia (MT) cartilage and compared between subjects with low KAM and high KAM. Biomechanical variables were compared between limbs.

RESULTS

The high KAM group had higher T1ρ for MT (p=0.01), central MT (p=0.05), posterior MF (p=0.04), posterior MT (p=0.01); and higher T2 for MT (p=0.02), MF (p=0.05), posterior MF (p=0.002) and posterior MT (p=0.01). During walking, ACL-R knees had greater flexion at initial contact (p=0.04), and lower KEM (p=0.02). During drop-landing, the ACL-R knees had lower KAM (p=0.03) and KFM (p=0.002).

CONCLUSION

Patients with ACL-R who have higher KAM during walking had elevated MR relaxation times in the medial knee compartments. These data suggest that those individuals who have undergone ACL-R and have higher frontal plane loading, may be at a greater risk of knee osteoarthritis.

Imaging following acute knee trauma

Joint injury has been recognized as a potent risk factor for the onset of osteoarthritis. The vast majority of studies using imaging technology for longitudinal assessment of patients following joint injury have focused on the injured knee joint, specifically in patients with anterior cruciate ligament injury and meniscus tears where a high risk for rapid onset of post-traumatic osteoarthritis is well known. Although there are many imaging modalities under constant development, magnetic resonance (MR) imaging is the most important instrument for longitudinal monitoring after joint injury. MR imaging is sensitive for detecting early cartilage degeneration and can evaluate other joint structures including the menisci, bone marrow, tendons, and ligaments which can be sources of pain following acute injury. In this review, focusing on imaging following acute knee trauma, several studies were identified with promising short-term results of osseous and soft tissue changes after joint injury. However, studies connecting these promising short-term results to the development of osteoarthritis were limited which is likely due to the long follow-up periods needed to document the radiographic and clinical onset of the disease. Thus, it is recommended that additional high quality longitudinal studies with extended follow-up periods be performed to further investigate the long-term consequences of the early osseous and soft tissue changes identified on MR imaging after acute knee trauma.

Patient-specific evaluation of knee disorders in clinical practice

BACKGROUND

Nowadays, an increasing number of patients expect their physician to provide a measureable and, therefore, comparable treatment effect that quantifies success or failure of the applied therapy. Unfortunately, different knee classification schemes applied to the same patient may provide diverging results. Therefore, the objective of this paper was to present recommendations to clinicians for a meaningful outcome assessment of their patients.

METHODS

Out of 39 knee evaluation systems available in the literature, we performed an elimination process based on the criteria (1) widespread use, (2) available reference values and (3) publication of at least one validation study.

RESULTS

Six clinical scores were detected which met the inclusion criteria. Owing to authors' recommendations and personal opinion the International Knee Documentation Committee (IKDC) Score, the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) were identified to be the most suitable outcome measures that enable patients a realistic assessment of their treatment effect compared with individuals in similar life situations.

CONCLUSION

To our opinion the IKDC should be applied to athletic patients suffering from post-traumatic knee symptoms who are younger than 50 years. For non-athletes aged 50 years and older the WOMAC is considered suitable whereas the KOOS is recommended to all other patients with knee disorders.

Treatment of meniscal tears: An evidence based approach

Treatment options for meniscal tears fall into three broad categories; non-operative, meniscectomy or meniscal repair. Selecting the most appropriate treatment for a given patient involves both patient factors (e.g., age, co-morbidities and compliance) and tear characteristics (e.g., location of tear/age/reducibility of tear). There is evidence suggesting that degenerative tears in older patients without mechanical symptoms can be effectively treated non-operatively with a structured physical therapy programme as a first line. Even if these patients later require meniscectomy they will still achieve similar functional outcomes than if they had initially been treated surgically. Partial meniscectomy is suitable for symptomatic tears not amenable to repair, and can still preserve meniscal function especially when the peripheral meniscal rim is intact. Meniscal repair shows 80% success at 2 years and is more suitable in younger patients with reducible tears that are peripheral (e.g., nearer the capsular attachment) and horizontal or longitudinal in nature. However, careful patient selection and repair technique is required with good compliance to post-operative rehabilitation, which often consists of bracing and non-weight bearing for 4-6 wk.

The effect of anterior cruciate ligament injury on bone curvature: exploratory analysis in the KANON trial

OBJECTIVE

Investigate the 5-year longitudinal changes in bone curvature after acute anterior cruciate ligament (ACL) injury, and identify predictors of such changes.

METHODS

In the KANON-trial (ISRCTN 84752559), 111/121 young active adults with an acute ACL tear to a previously un-injured knee had serial 1.5 T MR images from baseline (within 5 weeks from injury) to 5 years after injury. Of these, 86 had ACL reconstruction (ACLR) performed early or delayed, 25 were treated with rehabilitation alone. Measures of articulating bone curvature were obtained from computer-assisted segmentation of MR images. Curvature (mm(-1)) was determined for femur, tibia, medial/lateral femur, trochlea, medial/lateral tibia. Age, sex, treatment, BMI, meniscal injury, osteochondral fracture on baseline MR images were tested for association.

RESULTS

Over 5 years, curvature decreased in each region (P < 0.001) suggesting flattening of convex shapes and increased concavity of concave shapes. A higher BMI was associated with flattening of the femur (P = 0.03), trochlea (P = 0.007) and increasing concavity of the lateral tibia (LT) (P = 0.011). ACLR, compared to rehabilitation alone, was associated with flatter curvature in the femur (P < 0.001), medial femoral condyle (P = 0.006) and trochlea (P = 0.003). Any meniscal injury at baseline was associated with a more flattened curvature in the femur (P = 0.038), trochlea (P = 0.039), lateral femoral condyle (P = 0.034) and increasing concavity of the LT (P = 0.048).

CONCLUSION

ACL injury is associated with significant changes in articulating bone curvature over a 5 year period. Higher BMI, baseline meniscal injury and undergoing ACL reconstruction (as distinct from undergoing rehabilitation alone) are all associated with flattening of the articulating bone.

Anterior Cruciate Ligament OsteoArthritis Score (ACLOAS): Longitudinal MRI-based whole joint assessment of anterior cruciate ligament injury

OBJECTIVE

To develop a whole joint scoring system, the Anterior Cruciate Ligament OsteoArthritis Score (ACLOAS), for magnetic resonance imaging (MRI)-based assessment of acute anterior cruciate ligament (ACL) injury and follow-up of structural sequelae, and to assess its reliability.

DESIGN

Baseline and follow-up 1.5 T MRI examinations from 20 patients of the KANON study, a randomized controlled study comparing a surgical and non-surgical treatment strategy, were assessed for up to six longitudinal visits using a novel MRI scoring system incorporating acute structural tissue damage and longitudinal changes including osteoarthritis (OA) features. Joint features assessed were acute osteochondral injury, traumatic and degenerative bone marrow lesions (BMLs), meniscus morphology and extrusion, osteophytes, collateral and cruciate ligaments including ACL graft, Hoffa-synovitis and effusion-synovitis. Cross-sectional (baseline) and longitudinal (all time points and change) intra- and inter-observer reliability was calculated using weighted (w) kappa statistics and overall percent agreement on a compartmental basis (medial tibio-femoral, lateral tibio-femoral, patello-femoral).

RESULTS

Altogether 87 time points were evaluated. Intra-observer reliability ranged between 0.52 (baseline, Hoffa-synovitis) and 1.00 (several features), percent agreement between 52% (all time points, Hoffa-synovitis) and 100% (several features). Inter-observer reliability ranged between 0.00 and 1.00, which is explained by low frequency of some of the features. Altogether, 73% of all assessed 142 parameters showed w-kappa values between 0.80 and 1.00 and 92% showed agreement above 80%.

CONCLUSIONS

ACLOAS allows reliable scoring of acute ACL injury and longitudinal changes. This novel scoring system incorporates features that may be relevant for structural outcome not covered by established OA scoring instruments.

Post-traumatic knee osteoarthritis in the young patient: therapeutic dilemmas and emerging technologies

Traumatic knee injury is common in young adults and strongly contributes to premature development of knee osteoarthritis (OA). Post-traumatic knee OA poses a therapeutic dilemma to the physician, since no known therapy has an acceptable safety profile, effectively relieves joint pain, and enjoys reasonable patient acceptance. Consequently, these young patients will ultimately be faced with the decision to either undergo surgical intervention, despite prosthesis durability concerns, or to continue with ineffective nonsurgical treatment. Emerging therapies, such as biologics, disease-modifying drugs, partial joint resurfacings, and minimally invasive joint-unloading implants are currently being studied to fill this therapeutic void in the young patient with post-traumatic knee OA.

Basic science of anterior cruciate ligament injury and repair

Injury to the anterior cruciate ligament (ACL) is one of the most devastating and frequent injuries of the knee. Surgical reconstruction is the current standard of care for treatment of ACL injuries in active patients. The widespread adoption of ACL reconstruction over primary repair was based on early perception of the limited healing capacity of the ACL. Although the majority of ACL reconstruction surgeries successfully restore gross joint stability, post-traumatic osteoarthritis is commonplace following these injuries, even with ACL reconstruction. The development of new techniques to limit the long-term clinical sequelae associated with ACL reconstruction has been the main focus of research over the past decades. The improved knowledge of healing, along with recent advances in tissue engineering and regenerative medicine, has resulted in the discovery of novel biologically augmented ACL-repair techniques that have satisfactory outcomes in preclinical studies. This instructional review provides a summary of the latest advances made in ACL repair. Cite this article: Bone Joint Res 2014;3:20-31.

Mid-term results of transphyseal anterior cruciate ligament reconstruction in children and adolescents

BACKGROUND

Optimal therapy for anterior cruciate ligament (ACL) rupture in the paediatric population still provokes controversy. Although conservative and operative treatments are both applied, operative therapy is slightly favored. Among available surgical techniques are physeal-sparing reconstruction and transphyseal graft fixation. The aim of this study was to present our mid-term results after transphyseal ACL reconstruction.

METHODS

Fifteen young patients (mean age=12.8±2.6, range=6.2-15.8 years, Tanner stage=2-4) with open physis and traumatic anterior cruciate rupture who had undergone transphyseal ACL reconstruction with unilateral quadriceps tendon graft were prospectively analyzed. All children were submitted to radiological evaluation to determine the presence of clearly open growth plates in both the distal femur and proximal tibia. Postoperatively, all patients were treated according to a standardized rehabilitation protocol and evaluated by radiographic analysis and the Lysholm-Gillquist and IKDC 2000 scores. Their health-related quality of life was measured using the SF-12 PCS (physical component summary) and MCS (mental component summary) questionnaires.

RESULTS

Mean postoperative follow-up was 4.1 years. Mean Lysholm-Gillquist score was 94.0. Thirteen of the 15 knees were considered nearly normal on the IKDC 2000 score. The mean SF-12 questionnaire score was 54.0±4.8 for SF-12 PCS and 59.1±3.7 for SF-12 MCS. No reruptures were observed. Radiological analysis detected one knee with valgus deformity. All patients had a normal gait pattern without restrictions.

CONCLUSION

Transphyseal reconstruction of the anterior cruciate ligament shows satisfactory mid-term results in the immature patient.

Repeated autologous intraarticular blood injections as an animal model for joint pain in haemophilic arthropathy

Introduction

Haemophilic arthropathy following recurrent joint bleedings is one of the major disease-related complications in people with haemophilia (PWH), leading to mostly chronic joint pain. Since many antinociceptive principles interfere with the clotting system, PWH are restricted in treatment options, thereby defining a medical need for novel therapeutic principles. However, we lack the availability of an animal model for joint pain in haemophilic arthropathy for testing these.

Methods

In this study, we aimed to validate the rat model of repeated autologous intraarticular blood injections specifically for pain-related behavior. During an observation period of 50 days, groups of animals were injected weekly into one knee joint with either whole blood or cellular/plasma components.

Results

Injections induced primary hyperalgesia starting after the third injection, accompanied by mild functional gait changes and joint swelling. Secondary hyperalgesia and quantitative gait disturbances were not observed. This phenotype was most prominent in whole blood injected animals, with effect sizes of cells and plasma being additive. In order to differentiate haemophilia-related arthropathy from traumatic joint bleeding, another group was injected with whole blood only once, which did not cause any alterations.

Conclusions

Repeated autologous intraarticular injections of blood showed a time course, inflammatory response and reduction in pain thresholds similar to the signs and symptoms observed in PWH. Therefore, this model may be utilised in the future for testing novel antinociceptive principles in haemophilia-associated joint pain.

A comparative study of meniscectomy and nonoperative treatment for degenerative horizontal tears of the medial meniscus

BACKGROUND

It is still debated whether a degenerative horizontal tear of the medial meniscus should be treated with surgery.

HYPOTHESIS

The clinical outcomes of arthroscopic meniscectomy will be better than those of nonoperative treatment for a degenerative horizontal tear of the medial meniscus.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 102 patients with knee pain and a degenerative horizontal tear of the posterior horn of the medial meniscus on magnetic resonance imaging were included in this study between January 2007 and July 2009. The study included 81 female and 21 male patients with an average age of 53.8 years (range, 43-62 years). Fifty patients underwent arthroscopic meniscectomy (meniscectomy group), and 52 patients underwent nonoperative treatment with strengthening exercises (nonoperative group). Functional outcomes were compared using a visual analog scale (VAS) for pain, Lysholm knee score, Tegner activity scale, and patient subjective knee pain and satisfaction. Radiological evaluations were performed using the Kellgren-Lawrence classification to evaluate osteoarthritic changes.

RESULTS

In terms of clinical outcomes, meniscectomy did not provide better functional improvement than nonoperative treatment. At the final follow-up, the average VAS scores were 1.8 (range, 1-5) in the meniscectomy group and 1.7 (range, 1-4) in the nonoperative group (P = .675). The average Lysholm knee scores at 2-year follow-up were 83.2 (range, 52-100) and 84.3 (range, 58-100) in the meniscectomy and nonoperative groups, respectively (P = .237). In addition, the average Tegner activity scale and subjective satisfaction scores were not significantly different between the 2 groups. Although most patients initially had intense knee pain with mechanical symptoms, both groups reported a relief in knee pain, improved knee function, and a high level of satisfaction with treatment (P < .05 for all values). Two patients in the meniscectomy group and 3 in the nonoperative group with Kellgren-Lawrence grade 1 progressed to grade 2 at the 2-year follow-up.

CONCLUSION

There were no significant differences between arthroscopic meniscectomy and nonoperative management with strengthening exercises in terms of relief in knee pain, improved knee function, or increased satisfaction in patients after 2 years of follow-up.

Kinetic and kinematic differences between first and second landings of a drop vertical jump task: implications for injury risk assessments

BACKGROUND

Though the first landing of drop vertical jump task is commonly used to assess biomechanical performance measures that are associated with anterior cruciate ligament injury risk in athletes, the implications of the second landing in this task have largely been ignored. We examined the first and second landings of a drop vertical jump for differences in kinetic and kinematic behaviors at the hip and knee.

METHODS

A cohort of 239 adolescent female basketball athletes (age=13.6 (1.6) years) completed drop vertical jump tasks from an initial height of 31 cm. A three dimensional motion capture system recorded positional data while dual force platforms recorded ground reaction forces for each trial.

FINDINGS

The first landing demonstrated greater hip adduction angle, knee abduction angle, and knee abduction moment than the second landing (P-values<0.028). The second landing demonstrated smaller flexion angles and moments at the hip and knee than the first landing (P-values<0.035). The second landing also demonstrated greater side-to-side asymmetry in hip and knee kinematics and kinetics for both the frontal and sagittal planes (P-values<0.044).

INTERPRETATION

The results have important implications for the future use of the drop vertical jump as an assessment tool for anterior cruciate ligament injury risk behaviors in adolescent female athletes. The second landing may be a more rigorous task and provides a superior tool to evaluate sagittal plane risk factors than the first landing, which may be better suited to evaluate frontal plane risk factors.

Cartilage and bone markers and inflammatory cytokines are increased in synovial fluid in the acute phase of knee injury (hemarthrosis)--a cross-sectional analysis

PURPOSE

The aim of this cross-sectional study was to investigate concentrations of cartilage and bone markers, and pro-inflammatory cytokines in synovial fluid (SF) collected at different time-points from acutely injured knees with hemarthrosis and to compare these with SF concentrations of knees of age and gender-matched healthy reference subjects.

METHODS

SF was aspirated from the acutely injured knee of 111 individuals (mean age 27 years, span 13-64 years, 22% women). Concentrations of sulfated glycosaminoglycan (sGAG) were measured by Alcian blue precipitation whereas cartilage ARGS, bone biomarkers [osteocalcin (OCL), secreted protein acidic and rich in cysteine (SPARC) and osteopontin (OPN)] and pro-inflammatory cytokines [interleukin (IL)-1β, IL-6, IL-8 and tumor necrosis factor (TNF)-α] were analyzed using electrochemiluminescence. Samples were also analyzed with regard to time between injury and aspiration [same day (n = 29), 1 day (n = 31), 2-3 days (n = 19), 4-7 days (n = 20) and 8-23 days (n = 12)].

RESULTS

SF concentrations of ARGS (P < 0.001), SPARC (P < 0.001), OPN (P < 0.001), and all cytokines (P < 0.001), but not sGAG (P = 0.06) or OCL (P = 0.992), were significantly higher in injured knees compared to knees of reference subjects. The cartilage markers sGAG and ARGS were significantly higher in knees aspirated later than 1 day after injury, whereas concentrations of SPARC and OPN and all cytokines were higher in knees aspirated the same day as the injury and at all time-points thereafter.

CONCLUSIONS

Our results suggest that an acute knee injury is associated with an instant local biochemical response to the trauma, which may affect cartilage and bone as well as the inflammatory activity.

Prevalence and characteristics of unilateral knee osteoarthritis in a community sample of elderly Japanese: do fractures around the knee affect the pathogenesis of unilateral knee osteoarthritis?

BACKGROUND

The purpose of this study was to investigate the prevalence and characteristics of unilateral knee osteoarthritis (KOA), to investigate what percent of contralateral healthy knees in patients with unilateral KOA progress to KOA, and to investigate whether knee fractures influence unilateral KOA.

METHODS

Studies were performed every two years from 1997 to 2009 in Miyagawa village, for a total of seven studies. A total of 1239 village inhabitants aged ≥65 years participated in these studies at least once. KOA was defined as a Kellgren-Lawrence (K/L) grade ≥2. Based on the knee X-ray at the first examination, participants were divided into three groups: no KOA (N group), unilateral KOA (U group), and bilateral KOA (B group). The U group was divided into two subgroups: K/L grade II-I combination (II-I group), and the U group without the II-I combination (G>2 group). To investigate whether knee fractures influence unilateral KOA, the fracture history was considered.

RESULTS

The percentages of participants classified into the N, B, and U groups (II-I and G>2 group) were 68.4, 21.6, and 10.0% (7.8 and 2.1%), respectively. Most of the U group had the II-I combination (78.7%). The percentages of knee fractures in the N, B, II-I, and G>2 groups were 3.3, 5.3, 6.3, and 38.5%, respectively. Overall, 49.2% of the U group proceeded to bilateral KOA over an average of 5.3 years.

CONCLUSIONS

The prevalences of definite radiographic bilateral and unilateral KOA were 21.6 and 10.0%, respectively. Overall, 49.2% of the participants with unilateral KOA developed KOA in the contralateral knee over an average of 5.3 years. If bilateral KOA advanced simultaneously, the II-I group was considered to represent the midpoint of progression to bilateral KOA. Bilateral KOA advanced simultaneously except in cases with a history of knee trauma, such as fractures.

Effects of single-bundle and double-bundle ACL reconstruction on tibiofemoral compressive stresses and joint kinematics during simulated squatting

The purpose of this study was to compare tibiofemoral (TF) kinematics and TF compressive stresses between single bundle- (SB-) and double bundle-ACL reconstruction (DB-ACLR) during simulated squatting. Twelve matched pairs of fresh frozen cadaver knees were utilized. A simulated squat through 100° of knee flexion was performed in the ACL-intact joint. The ACL was transected and SB- and DB-ACLR procedures were performed in one knee of each pair. The squat was repeated. Knee kinematics were measured using a motion tracking system and the TF compressive forces were measured using thin film pressure sensors. The posterior shifts of the tibia for SB- and DB-ACLR knees were significantly greater than the ACL-intact condition for knee flexion angles 0° to 40° (p<.05). However, there was no difference between the SB- and DB-ACLR knees at any flexion angle (0° to 100°; p=.37). SB- and DB-ACLR knees had greater IE rotation than intact knees from 90° through 50° of flexion (p<.05), but not between 40° and full extension. There was no difference between SB- and DB-ACLR knees (p=.68). The TF compressive stresses of the DB-ACLR were significantly lower than intact for all angles except 10° (p=.06), whereas SB-ACLR knees did not differ from intact at flexion angles between 30° and 50° (p>.32). There were no significant differences between the two reconstruction conditions (p=.74). This study showed that there was no difference in the TF kinematics or compressive stresses between SB- and DB-ACLR, and only minor differences when compared to the intact state.

Effectiveness of anterior cruciate ligament injury prevention training programs

BACKGROUND

The objective of this study was to systematically review the literature on anterior cruciate ligament (ACL) injury prevention programs and to perform a meta-analysis to address three questions: First, what is the effectiveness of ACL injury prevention programs? Second, is there evidence for a "best" program? Third, what is the quality of the current literature on ACL injury prevention?

METHODS

We conducted a systematic review with use of the online PubMed, MEDLINE, EMBASE, CINAHL (Cumulative Index to Nursing and Allied Health), and Cochrane Central Register of Controlled Trials databases. Search terms were anterior cruciate ligament, knee, injury, prevention, and control. Data on study design and clinical outcomes were extracted independently in triplicate. After assessment of between-study heterogeneity, DerSimonian-Laird random-effect models were used to calculate pooled risk ratios and risk differences. The risk difference was used to estimate the number needed to treat (the number of individuals who would need to be treated to avoid one ACL tear).

RESULTS

The pooled risk ratio was 0.38 (95% confidence interval [CI], 0.20 to 0.72), reflecting a significant reduction in the risk of ACL rupture in the prevention group (p = 0.003). The number needed to treat ranged from five to 187 in the individual studies. Stratified by sex, the pooled risk ratio was 0.48 (95% CI, 0.26 to 0.89) for female athletes and 0.15 (95% CI, 0.08 to 0.28) for male athletes.

CONCLUSIONS

Our study indicated strong evidence in support of a significant effect of ACL injury prevention programs. Our pooled estimates suggest a substantial beneficial effect of ACL injury prevention programs, with a risk reduction of 52% in the female athletes and 85% in the male athletes.

Anterior cruciate ligament tears: conservative or surgical treatment? A critical review of the literature

PURPOSE

Is it rational to recommend surgical reconstruction of the torn anterior cruciate ligament to every patient? Is conservative management still a valid option?

METHOD

Through a literature review, we looked for the arguments from each side and checked their validity.

RESULTS

Unfortunately results of most studies cannot be compared because of the following reasons not exhaustively cited: studied populations differed with respect to age, sex, professional and sports activity level, lesions associated with ACL rupture, patient recruitment methods, time from injury to treatment and different therapeutic modalities. Furthermore, various methods were used to evaluate the clinical and radiological results and there was no consensus of their interpretation. Some authors assumed that the incidence of further meniscus lesions could probably be reduced if the torn ACL was surgically reconstructed. But, we have no evidence to believe that this would be due to the surgical repair rather than to a decrease of involvement in strenuous activities. At present it is not demonstrated that ACL-plasty can prevent osteoarthritis. Numerous factors could explain evolution to arthrosis whatever the treatment for the ACL-ruptured knee. Studies comparing surgical and conservative treatments confirm that ACL reconstruction is not the pre-requisite for returning to sporting activities. More recent and scientifically well-designed studies demonstrate that conservative treatment could give satisfactory results for many patients. They suggest some methods to help them choose the best treatment.

CONCLUSION

At present there are no evidence-based arguments to recommend a systematic surgical reconstruction to any patient who tore his ACL. Knee stability can be improved not only by surgery but also by neuromuscular rehabilitation. Whatever the treatment, fully normal knee kinematics are not restored. While the patients wish to go back to their sport and want everything possible done to prolong their ability to perform these activities, they should be informed that the risk of further knee lesions and osteoarthritis remains high, whatever the treatment, surgical or conservative.

LEVEL OF EVIDENCE

Systematic review of Level I, II, III and IV studies, Level IV.

Effects of short-term glucocorticoid treatment on changes in cartilage matrix degradation and chondrocyte gene expression induced by mechanical injury and inflammatory cytokines

Introduction

Traumatic joint injury damages cartilage and causes adjacent joint tissues to release inflammatory cytokines, increasing the risk of developing osteoarthritis. The main objective of this study was to determine whether the combined catabolic effects of mechanical injury, tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6)/soluble IL-6 receptor (sIL-6R) on cartilage could be abolished by short-term treatment with glucocorticoids such as dexamethasone.

Methods

In an initial dexamethasone-dose-response study, bovine cartilage explants were treated with TNFα and increasing concentrations of dexamethasone. Bovine and human cartilage explants were then subjected to individual and combined treatments with TNFα, IL-6/sIL-6R and injury in the presence or absence of dexamethasone. Treatment effects were assessed by measuring glycosaminoglycans (GAG) release to the medium and synthesis of proteoglycans. Additional experiments tested whether pre-exposure of cartilage to dexamethasone could prevent GAG loss and inhibition of biosynthesis induced by cytokines, and whether post-treatment with dexamethasone could diminish the effects of pre-established cytokine insult. Messenger ribonucleic acid (mRNA) levels for genes involved in cartilage homeostasis (proteases, matrix molecules, cytokines, growth and transcription factors) were measured in explants subjected to combined treatments with injury, TNFα and dexamethasone. To investigate mechanisms associated with dexamethasone regulation of chondrocyte metabolic response, glucocorticoid receptor (GR) antagonist (RU486) and proprotein convertase inhibitor (RVKR-CMK) were used.

Results

Dexamethasone dose-dependently inhibited GAG loss and the reduction in biosynthesis caused by TNFα. The combination of mechanical injury, TNFα and IL-6/sIL-6R caused the most severe GAG loss; dexamethasone reduced this GAG loss to control levels in bovine and human cartilage. Additionally, dexamethasone pre-treatment or post-treatment of bovine explants lowered GAG loss and increased proteoglycan synthesis in cartilage explants exposed to TNFα. Dexamethasone did not down-regulate aggrecanase mRNA levels. Post-transcriptional regulation by dexamethasone of other genes associated with responses to injury and cytokines was noted. GR antagonist reversed the effect of dexamethasone on sulfate incorporation. RVKR-CMK significantly reduced GAG loss caused by TNFα + IL-6 + injury.

Conclusions

Short-term glucocorticoid treatment effectively abolished the catabolic effects exerted by the combination of pro-inflammatory cytokines and mechanical injury: dexamethasone prevented proteoglycan degradation and restored biosynthesis. Dexamethasone appears to regulate the catabolic response of chondrocytes post-transcriptionally, since the abundance of transcripts encoding aggrecanases was still elevated in the presence of dexamethasone.

Three-dimensional joint kinematics of ACL-deficient and ACL-reconstructed knees during stair ascent and descent

Mechanical environmental changes in the knee are induced by altered joint kinematics under cyclic loading during activities of daily living after anterior cruciate ligament (ACL) injury. This is considered a risk factor in progressive cartilage degeneration and the early onset of osteoarthritis following ACL injury and even after reconstructive surgery. The purpose of this study was to examine 3D joint kinematics of ACL-deficient and ACL-reconstructed knees to health controls during stair ascent and descent. A 3D optical video motion capture system was used to record coordinate data from reflective markers positioned on subjects as they ascended and descended a custom-built staircase. Spatiotemporal gait and knee joint kinematic variables were calculated and further analyzed. The ACL-deficient knees exhibited a significant extension deficit compared to the ACL-intact controls. A more varus and internally rotated tibial position was also identified in the ACL-deficient knees during both stair ascent and descent. The ACL-reconstructed knees exhibited less abnormality in both spatiotemporal gait parameters and joint kinematics, but these variables were not fully restored to a normal level. The kinematic profiles of the ACL-reconstructed knees were more similar to those of the ACL-deficient knees when compared to the ACL-intact knees. This suggests that the ACL-reconstructed knees had been "under-corrected" rather than "over-corrected" by the reconstructive surgery procedure. Findings from this study may provide more insight with respect to improving ACL reconstruction surgical techniques, which may aid the early progression of cartilage degeneration in ACL-reconstructed knees.

Change in cartilage thickness, posttraumatic bone marrow lesions, and joint fluid volumes after acute ACL disruption: a two-year prospective MRI study of sixty-one subjects

BACKGROUND

Little is known about early morphologic change occurring with an acute injury of the anterior cruciate ligament. Magnetic resonance imaging was used in this study to investigate the two-year change in cartilage thickness, bone marrow lesions, and joint fluid of knees with acute anterior cruciate ligament injury treated surgically or nonsurgically and to identify factors associated with these changes.

METHODS

Sixty-one subjects (sixteen women and forty-five men with a mean age of twenty-six years) with acute anterior cruciate ligament injury to a previously uninjured knee were examined with use of a 1.5-T magnetic resonance imaging scanner at baseline and at three, six, twelve, and twenty-four months after the injury. Thirty-four subjects received rehabilitation and early anterior cruciate ligament reconstruction (a median of 44.5 days after the injury), eleven subjects received rehabilitation and a delayed anterior cruciate ligament reconstruction (408 days), and sixteen received rehabilitation alone. Morphologic measures were obtained from computer-assisted segmentation of magnetic resonance images. Factors tested for association were age, sex, activity level, treatment, and osteochondral fracture at baseline.

RESULTS

After twenty-four months, significant cartilage thinning occurred in the trochlea of the femur (mean, -4.3%; standard response mean = 0.88), whereas significant cartilage thickening occurred in the central medial aspect of the femur (mean, +2.7%; standard response mean = 0.46). A younger age at the time of injury was a risk factor for thickening in the central medial aspect of femur, whereas older age at injury was a risk factor for thinning in the trochlea of the femur. Treatment of the torn anterior cruciate ligament was not related to these changes nor was activity level or an osteochondral fracture at baseline. Posttraumatic bone marrow lesions in the lateral aspect of the tibia resolved completely in fifty-four of fifty-eight knees (median, six months) and lesions in the lateral aspect of the femur resolved completely in forty-four of forty-seven knees (median, three months); however, thirty new bone marrow lesions developed in the lateral aspect of twenty-one knees over the two-year period. None of the factors were related to the development of bone marrow lesions.

CONCLUSIONS

Morphologic change as visualized on magnetic resonance imaging occurs in the knee over the first two years after acute anterior cruciate ligament injury as demonstrated by cartilage thickening (central medial aspect of the femur), cartilage thinning (trochlea of the femur), the resolution of posttraumatic bone marrow lesions in the lateral part of the knee, and the development of new bone marrow lesions laterally. Age and male sex were independent risk factors for change in cartilage morphology.

The potential for primary repair of the ACL

The objective of this work is to assess the feasibility of successfully repairing the torn anterior cruciate ligament (ACL). Two major motivators for developing a new treatment for ACL injuries are the recently reported high rates of osteoarthritis, after conventional ACL reconstruction, and the problem of how to safely treat skeletally immature patients. A key factor in developing such a technique was the identification of the main inhibitor of intrinsic ACL healing-the lack of clot formation between the 2 torn ends of the ligament. A bioactive and biocompatible scaffold, which could be placed in the wound site to enhance cellular proliferation and biosynthesis, was developed. This biomaterial has shown promising functional outcomes in several large animal models of primary repair of partial and complete ACL transection over 4 to 14 weeks, suggesting potential for a successful, future clinical application.

A systematic review of clinical outcomes in patients undergoing meniscectomy

Knee meniscectomy is the most common procedure performed by orthopaedic surgeons. While it is generally believed that loss of meniscal tissue leads to osteoarthritis and poor knee function, many variables may significantly influence this outcome. Through literature search engines including PubMed and Ovid, 4 randomized controlled trials, 2 prospective cohorts, and 23 retrospective cohorts that fit the criteria for level I, II, and III level of evidence were included in this systematic review. For the level III evidence studies, follow-up of 5 years or more was required. Preoperative and intraoperative predictors of poor clinical or radiographic outcomes included total meniscectomy or removal of the peripheral meniscal rim, lateral meniscectomy, degenerative meniscal tears, presence of chondral damage, presence of hand osteoarthritis suggestive of genetic predisposition, and increased body mass index. Variables that were not predictive of outcome or were inconclusive or had mixed results included meniscal tear pattern, age, mechanical alignment, sex of patient, activity level, and meniscal tears associated with anterior cruciate ligament (ACL) reconstruction. While an intact meniscus or meniscal repair was generally favorable in the ACL-reconstructed knees, meniscal repair of degenerative meniscal tissue was not favorable. There is a lack of uniformity in the literature on this subject with a preponderance of lower level evidence. Although randomized controlled trials are considered to be the gold standard in medical research, a multicenter prospective cohort design may be more appropriate in assessing the long-term outcome of meniscal surgery and the role that multiple preoperative and intraoperative variables may play in clinical outcomes. In addition, future studies should include factors not assessed or adequately evaluated by several of the included studies, such as meniscal tear pattern, age, mechanical alignment, sex of the patient, activity level, meniscal tears associated with other injuries such as the ACL, smoking, and the effect of previous surgery.

Translational studies in anterior cruciate ligament repair

Translational research, which can be explained as the principle of combining advances in both basic research and clinical understanding in a bedside-to-bench-to-bedside approach, has become one of the central themes of present-day medical research. One orthopedic problem that has strongly benefited from such an approach is tissue-engineering-enhanced primary repair of the anterior cruciate ligament. Recent years have shown a clearer definition of the clinical problem and established an underlying mechanistic cause of the incapacity of the anterior cruciate ligament to heal-the premature loss of provisional scaffold in the wound site. These clinical findings were then translated into a research objective, namely, to replace the missing scaffold with a biomaterial with appropriate structural and bio-stimulatory characteristics. Subsequently, a tissue-engineering-based treatment using a collagen-platelet composite was developed and tested in vitro. After proofing the efficacy of this new treatment in the laboratory, it was translated into a potential clinical application, which showed highly successful results in structural integrity and biomechanical capacity in large animal testing. This approach of defining the scientific mechanism underlying a clinical observation and then using that information to design new therapies is but one example of how translational research in tissue engineering can help define and develop new treatments for challenging problems faced by patients.