Clinical and Radiological Outcomes After Isolated Anterior Horn Repair of Medial and Lateral Meniscus at 24 Months' Follow-up, With the Outside-In Technique

Abstract

Background The effects of repair of isolated anterior horn meniscus lesions have not been thoroughly described in the literature. We aimed to evaluate outcomes with subjective clinical scores and imaging modalities after repair of isolated anterior horn tears, at 24 months' follow-up. Methods Records of all patients that opted for surgical repair of isolated, anterior horn tears of the medial and lateral meniscus were retrospectively reviewed, between 2016 and 2018. All patients were treated with arthroscopic outside-in technique by the same surgeon. Preoperative and postoperative clinical files were accessed to recover records of preoperative symptomatology, patient-reported scores [International Knee Documentation Committee (IKDC) rating, Lysholm score and Tegner activity level], preoperative and postoperative MRI data and time from injury to surgery. Results Mean age of eight patients was 25.25 years (range 18-37 years). Diagnostic preoperative MRI revealed isolated anterior horn tear of the lateral meniscus and medial meniscus in five patients and an isolated anterior horn tear of the medial meniscus in three patients. Mean time from injury to surgical repair was 23.75 days (range 7-43). We considered seven out of eight repairs to be successfully healed. At 24 months' follow-up: Mean Lysholm score was 92.25 (range 89-95), Tegner activity scale score was 6.5 (range 5-8) and IKDC score was 91.78 (range 87.8-94.4). All scores significantly improved compared to preoperative values (p<0.001). Conclusions Outside-in is a reliable technique to repair meniscal anterior horn tears, both medially and laterally, with high healing rates and patient satisfaction in young, active patients.

Keywords: anterior horn meniscus; meniscus anterior horn radiological anatomy; meniscus outside-in; meniscus repair; meniscus surgery.

Figure 1. Outside-in technique.

A. Arthroscopic image of the first needle, loaded with the PDS suture. The free ends of the suture are tied together. B. Arthroscopic image of suture passing through the previously created loop, with gentle manipulation of the two needles.

Figure 2. Outside-in technique.

A. Demonstration of suture passing through the loop on anatomic high-fidelity training model. B, C. Grasping of suture free end and pulling outside the joint. D. While holding the first free end of the second suture (1), the other free end of the same suture (2), lies free outside the joint (previously pulled through the arthroscopic portal). The loop created by the first suture is pulled outside the joint (arrows), along with the other suture.

Figure 3. MRI pre-op and post-op.

A. T2 sagittal image of the right knee of a 22-year-old female patient with a tear (yellow arrow) in the anterior horn of the lateral meniscus. B. STIR sagittal image of the same patient 12 months postoperatively, where a meniscal cyst is formed (red arrow).

Figure 4. MRI pre-op and post-op.

A. Sagittal PD FSE image of the right knee of an 18-year-old male patient with a tear (yellow arrow) in the anterior horn of the lateral meniscus. B. Coronal STIR and C. Sagittal PD FSE image of the same patient 12 months postoperatively, depicting a healed meniscus (red cycle) with signal grade 1.

Figure 5. MRI pre-op and post-op.

A. Sagittal PD FSE image of the left knee of an 18-year-old male patient with a tear (yellow arrow) in the anterior horn of the lateral meniscus. B. Sagittal PD FSE image of the same patient 12 months postoperatively with a healed meniscus (red cycle).