The meniscal tear outcome (METRO) review: A systematic review summarising the clinical course and outcomes of patients with a meniscal tear

The recovery trajectory of anterior cruciate ligament ruptures in randomised controlled trials: A systematic review and meta-analysis of operative and nonoperative treatments

PURPOSE

The purpose of this research was to understand the trajectory of recovery following anterior cruciate ligament (ACL) reconstruction compared to nonoperative treatments.

METHODS

A systematic review and meta-analysis approach was used to evaluate randomised controlled trials (RCTs). A comprehensive search was conducted on databases including Medline, Embase, Web of Science and The Cochrane Central Register of Controlled Trials up until 18 May 2023. The study focused on full-text RCTs involving patients with partial or complete ACL tears. Included were studies focusing on patients undergoing ACL reconstruction or nonoperative care. The primary outcome was characterising the effects of treatments and tracking changes in International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC) outcomes over time. The secondary outcome was characterising and tracking the changes of the knee injury and osteoarthritis outcome score subscales, ACL-quality-of-life questionnaire, Lysholm, Tegner and CKRS scores.

RESULTS

A total of 84 RCTs were included. The pooled standardised mean changes for the IKDC compared with baseline were: 2.0 (95% confidence interval [CI]: 0.3-3.6) at 3 months, 2.2 (95% CI: 0.9-3.6) at 6 months, 2.2 (95% CI: 0.8-3.6) at 12 months and 2.3 (95% CI: 1.3-3.4) at 24 months. Graphs illustrating IKDC scores over time further emphasise these findings, showing a sustained improvement over time to 12 months, with a plateauing of scores past this time point. Our secondary outcome patient-reported outcome measures (PROMs) also showed a similar pattern with scores plateauing at the 12-months mark.

CONCLUSION

Our findings suggest that the IKDC score and other PROMs are effective for tracking recovery up to 12 months. Other PROMs show pain and daily activities generally recover within 6 months, and quality of life improves up to 12 months, but PROMs show minimal improvement beyond this period. This inconsistency with a return sport period indicates that PROMs may lack the sensitivity required to assess this aspect of recovery accurately.

LEVEL OF EVIDENCE

Level I.

Posterior Medial Meniscus Root Tears: Clinical Implications, Surgical Management, and Post-operative Rehabilitation Considerations

Tears of the posterior medial meniscus root (PMMR) are common in older patients and reportedly contribute to rapid joint degeneration over time. Recognition of these tear types and the appropriate diagnosis through clinical exam and diagnostic imaging have improved significantly in recent years, as have surgical techniques to address them. Standardized post-operative rehabilitation protocols specific to PMMR repair have not been established or well understood in the scientific literature. Thus, clinicians have little guidance for managing post-operative care. Upon diagnosis of a root tear, appropriate surgical treatment, with appreciation for native anatomy and function of the meniscus root, is a critical first step for recovery. Post-operative rehabilitation protocols should account for biomechanical considerations unique to root tears, because they can destabilize the entire meniscus and compromise its native function. Rehabilitation specialists can apply known science regarding the influence of joint motion, muscle strengthening activities, gait, squatting, and progressive loading activities on the healing meniscus to guide post-operative recovery. This knowledge, complemented with existing foundational principles for sound post-operative rehabilitation, can optimize recovery for patients following PMMR repair. The purpose of this clinical commentary is to explore clinical questions related to 1) PMMR injury epidemiology, 2) diagnosis and surgical management of PMMR tears, and 3) critical considerations for safe and effective post-operative rehabilitation. Level of Evidence: 5.

MCP-1 in synovial fluid as a predictor of inferior clinical outcomes after meniscectomy

PURPOSE

To evaluate knee intra-articular cytokine concentrations in patients undergoing isolated meniscectomy and determine if these concentrations are associated with clinical outcomes.

METHODS

Concentrations of ten biomarkers were quantified in synovial fluid aspirated from the operative knees of patients who underwent isolated meniscectomy from 10/2011-12/2019. Patients completed a survey at final follow-upincluding VAS, Lysholm, Tegner, and KOOS Physical Function Short Form (KOOS-PS). Failure was defined as subsequent TKA or non-achievement of the Patient Acceptable Symptom State (PASS) for knee pain defined as VAS > 27/100. Regression analysis investigating the relationship between cytokine concentrations and failure was performed.

RESULTS

The study consisted of 100 patients, including 50 males (50.0%) with a mean age of 51.1 ± 11.7 years, a median BMI of 28.9 kg/m2 [25.5, 32.4], and a mean follow-up of 8.0 ± 2.2 years. There were no demographic or clinical differences between failures (n = 41) and non-failures (n = 59) at baseline. Monocyte Chemotactic Protein 1 (MCP-1) concentration was significantly higher in failures than in non-failures (344.3 pg/ml vs. 268.6 pg/ml, p = 0.016). In a regression analysis controlling for age, sex, BMI, symptom duration, length of follow-up, and ICRS grade, increased MCP-1 was associated with increased odds of failure (p = 0.002).

CONCLUSIONS

The concentration of MCP-1 on the day of arthroscopic meniscectomy was predictive of failure as defined by an unacceptable pain level at intermediate- to long-term follow-up. This finding may help identify patients at high risk for poor postoperative outcomes following isolated meniscectomy and serve as a target for future postoperative immunomodulation research.

Degradation of Proteoglycans and Collagen in Equine Meniscal Tissues

Investigate meniscal extracellular matrix degradation. Equine menisci (n = 34 from 17 horses) were studied. Site-matched sections were cut and scored from three regions (ROIs; n = 102) and stained for histology, proteoglycan (safranin O and fast green), aggrecan, and collagen cleavage (NITEGE, DIPEN, and C1,2C antibodies, respectively). Picrosirius red and second harmonic generation microscopy were performed to investigate collagen ultrastructure. A total of 42 ROIs met the inclusion criteria and were included in the final analysis. The median (range) ROI histological score was 3 (0-9), providing a large spectrum of pathology. The median (range) proteoglycan score was 1 (0-3), representing superficial and central meniscal loss. The median (range) of DIPEN, NITEGE, and C1,2C scores was 1 (0-3), revealing immunostaining of the femoral and tibial surfaces. The proteoglycan scores exhibited significant positive associations with both histologic evaluation (p = 0.03) and DIPEN scores (p = 0.02). Additionally, a robust positive association (p = 0.007) was observed between the two aggrecanolysis indicators, NITEGE and DIPEN scores. A negative association (p = 0.008) was identified between NITEGE and histological scores. The C1,2C scores were not associated with any other scores. Picrosirius red and second harmonic generation microscopy (SHGM) illustrated the loss of the collagen matrix and structure centrally. Proteoglycan and collagen degradation commonly occur superficially in menisci and less frequently centrally. The identification of central meniscal proteoglycan and collagen degradation provides novel insight into central meniscal degeneration. However, further research is needed to elucidate the etiology and sequence of degradative events.

Non-operative Management of Acute Knee Injuries

PURPOSE OF REVIEW

Acute knee injuries are commonly encountered in both the clinical and sideline setting and may be treated operatively or non-operatively. This article describes an evidence-based approach to non-operative acute knee injury. This includes history, physical exam, imaging, and initial management. In addition, the non-operative management of three such injuries-ligament injury, meniscus injury, and patellar dislocation injury-will be discussed via a case-based practical approach.

RECENT FINDINGS

Aside from grade III ACL tears, most acute knee ligament injuries, especially in the absence of other concurrent injuries, can be treated non-operatively. There is new evidence that acute traumatic meniscus tears in those younger than 40 can be successfully treated non-operatively and can do equally, as well as those that undergo surgery, at 1 year out from injury. Based on the current literature, a short period of knee bracing in extension with progression to weightbearing to tolerance is recommended after initial patellar dislocation. Many of the most common acute knee injuries, including MCL tears, meniscus tears, and patellar dislocations, can be managed non-operatively. A detailed systemic approach to initial evaluation, including pertinent history, physical exam, and appropriate imaging, is essential and complementary to the subsequent non-operative treatment algorithm.