Specific Considerations

Patient age. There is conflicting literature as to the effect of patient age on surgical outcomes after meniscal repair. On the one hand, meniscal tissue from patients over 40 years of age has less cellularity and decreased healing response than tissue from younger patients, suggesting a lower failure rate in young patients. However, on the other hand, it has been shown that the healing of repaired meniscal tears is poor in young patients (children and adolescents), despite better intrinsic healing potential. Furthermore, a large database study showed that older age is associated with decreased risk of subsequent meniscectomies after meniscal repair. One possible reason is the higher demands in daily living, occupation, and sports in the young population. Published evidence suggests ^, suggests that there is no significant difference in meniscal repair failures as a function of age. Therefore, age alone should not be considered as an absolute contraindication to meniscal repair, and should be taken into consideration with other factors.

Meniscal tear chronicity. Chronicity of symptoms could indicate a degenerative meniscal tear and osteoarthritic joint changes. A comprehensive arthroscopic evaluation of the meniscal tear tissue and chondral status could also indicate a degenerative etiology. It has been shown that the healing potential in the setting of chronic degeneration is low, ^, and repair is not recommended in this scenario.

Meniscal tear patterns. Favorable tear patterns with better healing potential are vertical longitudinal tears, ^, whereas less favorable patterns include complete radial, oblique, horizontal cleavage, and complex patterns. ^{, , ,} Nevertheless, the usage of new techniques and instrumentation shows encouraging results in more challenging meniscal tears patterns, including complete radial tears ^, and meniscal root tears or avulsions, where repair is believed to aid in delayed progression of knee osteoarthritis. ^, Lastly, medial meniscocapsular tears (“Ramp” lesions), which have regained attention in recent years have shown good healing potential and clinical outcomes after repair ( Fig. 2.1 and 2.2 ).

Radial tear

(A) and (B) Coronal magnetic resonance imaging slices showing radial split in the posterior horn lateral meniscus all the way to the capsule. White arrows indicate the absence of meniscal tissue within the radial tear. (C) There is a large radial split to the right of the probe with distraction at the site of the tear and clot. (D) A single all-inside suture device across the tear.

Root tear

(A) Shaver inserted to debride the root edge. (B) Probe displacing the root tear. (C) Suture to shuttle a suture loop, which will then be used as “luggage tag.” (D) Completed repair with suture through drill hole in the tibia, repairing meniscus root anatomically.

Meniscal injury not indicated for repair. Small or partial-thickness tears can heal without intervention. In addition, stable peripheral tears can be treated with abrasion and trephination only (e.g., lateral meniscus tears near the popliteal hiatus). ^{, ,} Overtreatment with unnecessary repair or over repair exposes patients to avoidable risks.

Medial versus lateral tears. There is no conclusive evidence as to whether or not the healing potential in the medial and lateral meniscus is different. Older reports suggested better healing potential in the lateral meniscus; however, more recent literature did not support these findings. Regardless of healing potential, it has been shown that lateral meniscectomy has more severe consequences than medial meniscectomy, and this should be considered in the decision-making process.

Vascularity. The outer third of the meniscus (the red-red zone) has the greatest healing potential owing to the presence of the perimeniscal capillary plexus. In contrast, limited healing capacity should be expected in the central and inner thirds, which are avascular and aneural. A distance of 0 to 2 mm of the tear from the menisco capsular junction has been identified as the greatest predictor for healing. Nevertheless, it has been shown that repairing tears in the avascular zones can also have good clinical outcomes in a high percentage of patients. ^,

Instability. Knee instability jeopardizes meniscal repair integrity and healing. Biomechanical and clinical studies have proved the protective effect of regaining knee stability by anterior cruciate ligament reconstruction (ACLR) on meniscal repairs. Surgeons must not rely only on physical examination and imaging to rule out instability, but must also assess it by examination under anesthesia before performing meniscal repair. When instability is diagnosed, it should be addressed, preferably at the same time the meniscus is repaired.

Concomitant ACLR. Multiple studies have reported higher healing rates of meniscal repairs in conjunction with an ACLR in comparison to isolated meniscal repairs. ^, Growth factors and pluripotent cells released after bone-tunnel drilling, as well as favorable mechanism of injury secondary to instability in comparison to isolated meniscal injury mechanisms, are acceptable theories. ^,

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  Recognition: No improvement or worsening of symptoms after the surgical intervention, failure of repair proven be physical examinations and imaging (magnetic resonance imaging [MRI], computed tomography [CT] arthrography).

  
  
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  Management: Thorough evaluation for of all aforementioned conditions. Repair failure because of poor patient selection will require a reoperation with partial meniscectomy.

Improper Repair Technique

The location, pattern, and size of tears should dictate the preferred repair technique. Improper choice of technique will result in more challenging procedure and cause unnecessary additional injury. ^,

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  Prevention: Arthroscopic assessment of meniscal tear characteristic before choosing a repair technique. Preferable combinations are anterior horn tear with an outside-in technique and body/posterior horn tears with inside-out or all-inside techniques. Inside-out is still considered the gold standard.

  
  
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  Recognition: Technical difficulty performing the repair in a specific technique.

  
  
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  Management: Surgeons must be prepared to change repair techniques intraoperatively and consider hybrid repair in specific scenarios.

Improper Suture Material and Pattern

Using unsuitable suture material or suture pattern may result inferior biomechanical construct and lead to failure and poor clinical outcomes.

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  Prevention: Braided, nonabsorbable suture is the preferred suture for meniscal repair. Nonabsorbable suture allows stable and longer fixation, supporting the healing and remodeling process. Monofilaments increase the risk of cut-through. Vertical mattress suture pattern is biomechanically superior to horizontal configurations. It is recommended that sutures be placed in 3-to 5-mm intervals. ^{, ,}

  
  
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  Recognition: Postrepair assessment with arthroscopic probe will demonstrate compromised integrity and strength of the repair.

  
  
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  Management: Replace inappropriate sutures. Place vertical mattress configuration when possible.

Over- or Undertensioning of Sutures

Improper tension of sutures will compromise the repair construct. Undertension will result in an unstable construct, and overtension can damage meniscal tissue. In both cases healing capacity will be compromised. ^,

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  Prevention: Surgeons should tighten sutures under visual control and consider use of instrumentation that facilitates tensioning the sutures (knot pushers, arthroscopic probe).

  
  
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  Recognition: Postrepair assessment with arthroscopic probe will demonstrate over- or undertensioning of the repair.

  
  
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  Management: Replace inappropriate sutures.

Iatrogenic Meniscal and Chondral Injuries

The manipulation of instruments inside the knee during arthroscopic meniscal repair may result in iatrogenic chondral or meniscal damage, especially in more challenging tear locations such as the posterior horn of medial meniscus, particularly in stiff or tight knees.

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  Prevention: Adequate visualization and access to the tear site is key to a successful intervention. Better visualization can be achieved with changing portal locations, adding additional portal, changing camera/instrumentation portal, changing to 70 degrees arthroscope, applying additional varus or valgus load to improve exposure, using cannulas, and performing percutaneous pie-crusting of the superficial medial collateral ligament (MCL) for medial-sided pathology ^, .

  
  
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  Recognition: Postrepair assessment of the knee joint and intraarticular structures, specifically meniscus and cartilage.

  
  
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  Management: Excessive meniscal injury may require debridement of injured tissue. Cartilage injury may require debridement or repair of unstable lesions. Microfracture or chondroplasty are also options.

Saphenous Nerve and Vein Injury

The saphenous nerve travels on the undersurface of sartorius, anterior to gracilis and superficial to semimembranosus, between layer 1 and 2 of the MCL. Medial-sided repairs are associated with injury to these structures, especially repair of the posterior horn of the medial meniscus.

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  Prevention: Surgeons must be familiar with the anatomy, using safety medial incisions through layer 1 of MCL and making sure sutures adhere to layer 2 (superficial MCL). Transillumination of the saphenous vein from the inferolateral portal is another technique described to help with saphenous nerve identification. The nerve is just posterior to the vein.

  
  
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  Recognition: Sensation deficits on the medial foot/leg, persistent medial-sided neuropathic pain, and positive Tinel sign.

  
  
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  Management: Neuropathic pain may require surgical exploration and excision of neuroma or release of nerve.

Peroneal Nerve Injury

The common peroneal nerve travels medially to the biceps femoris muscle and laterally to the lateral head of gastrocnemius. At the joint line it lies posterior and deep to the biceps femoris. Lateral-sided repairs are associated with injury to the common peroneal nerve, especially the more posterior the repair and the more divergent the sutures. ^{, ,}

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  Prevention: Surgeons must be familiar with the anatomy. Safe lateral zone for suture passage is between the iliotibial band anteriorly and the biceps femoris posteriorly. One must use a spoon or Henning retractor positioned by an assistant who can retrieve needles as they exit the posterolateral capsule. The procedure must be done with the knee flexed to 90 degrees, which further removes the peroneal nerve from the joint capsule.

  
  
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  Recognition: Motor deficits with ankle/toe dorsiflexion and sensation deficit in the lateral leg/dorsal foot. Electromyography may help with diagnosis and monitoring nerve function.

  
  
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  Management: Purely sensory deficits are usually treated nonoperatively. Exploration is indicated for complete neurapraxia that does not resolve. If significant laceration or injury is found, primary repair or grafting is indicated.

Popliteal Vessels Injury

The popliteal neurovascular bundle is in close proximity to the posterior horn of the lateral meniscus. It has been shown that penetrating posterior meniscal tissue in the direction of popliteal vessels without a depth limiter can result popliteal artery injury. ^,

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  Prevention: Surgeons must be familiar with the anatomy. In case visualization of needle tips is not possible, mechanical restriction of penetration to meniscal tissue should be used.

  
  
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  Recognition: Excessive intraoperative bleeding should warrant a prompt assessment for possible popliteal artery or vein injury. This should include hemodynamic evaluation, distal pulses palpation, presence of late bruits or thrills behind the knee (as a manifestation of pseudoaneurysm), and vascular studies.

  
  
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  Management: Vascular consultation and intervention in case of popliteal artery injury. Fasciotomies should be considered if arterial injury leads to prolonged ischemia.

Lateral Genicular Artery Injury

The lateral genicular artery (LGA) crosses the knee capsule in proximity to the lateral meniscus at the level of the joint line, and lateral meniscal repair can cause injury to this vessel.

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  Prevention: Surgeons must be familiar with the anatomy. Adequate surgical exposure in cases of concern will enable preservation of this artery.

  
  
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  Recognition: Postoperative hematoma or hemarthrosis. Can potentially inhibit healing of meniscal repair because of disruption of local blood supply.

  
  
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  Management: Close follow-up in the initial postoperative period. In case of large hematoma and significant knee effusion, aspiration and compressive dressing are options.

Infection

Post meniscal repair infections can be superficial or deep. Deep infections are considered septic arthritis, and their incidence based on a large database in the United States is reported to be 0.17% to 0.30%. Delayed or improper management of an infected joint can have devastating results.

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  Prevention: Use of appropriate sterile technique during the arthroscopy. Avoidance of intraarticular intraoperative corticosteroid injections. Layered and meticulous surgical wound closure. Close follow-up in the immediate postoperative period.

  
  
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  Recognition: Clinical symptoms of infection (fever, local or joint tenderness, effusion, redness, warmth, swelling, wound dehiscence and drainage), laboratory supporting findings (elevated erythrocyte sedimentation rate, serum C-reactive protein, white blood cell count), knee aspiration with supporting Gram stain, cell counts, and culture findings.

  
  
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  Management: Sequential arthroscopic irrigation and debridement and intravenous antibiotics are the mainstay of treatment. The literature has shown that it is generally recommended to save the repaired meniscus in these cases and follow up closely.

Recurrent Tear

Additional injury, joint instability, and an aggressive rehabilitation protocol which involves early full weight bearing and deep squats can all be reasons for recurrent tear at the repaired meniscus location.

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  Prevention: Guiding and educating patients and therapists on the importance of adhering to a proven postoperative rehabilitation protocol and avoiding high-risk activities. Addressing and treating joint instability during the meniscal repair or staging it.

  
  
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  Recognition: A brief period of improvement in symptoms followed by recurrence of symptoms. Supportive imaging studies: MRI, magnetic resonance arthrography, CT arthrography. Second-look arthroscopy is the gold standard.

  
  
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  Management: Arthroscopic meniscal repair versus partial meniscectomy.