All-Suture, All-Inside Meniscus Repair Is Safe and Provides Favorable Short-Term Clinical Outcomes

Purpose

To evaluate short-term patient-reported outcomes (PROs), complications, and reoperations after all-inside meniscus repair using an all-suture implant.

Methods

A review of a prospectively maintained database was performed to identify patients who underwent all-inside meniscus repair using a knotless, tensionable, all-suture implant by the senior author between November 2019 and December 2023. PROs (including Knee Single Assessment Numerical Evaluation, pain visual analog scale, and Patient-Reported Outcomes Measurement Information System scores, as well as Knee Injury and Osteoarthritis Outcome Score [KOOS] subscales), and charts were analyzed to monitor change over time. Mixed linear regression, analysis of variance, and estimated marginal means were used to determine factors associated with improved or worsening outcomes.

Results

Sixty-three patients were deemed eligible for inclusion. The minimum length of follow-up was 7.33 months (mean, 16.32 months; range, 7.33-43.82 months). All assessed PROs at 6 months postoperatively and final follow-up were significantly improved compared with the preoperative values ( P <.001 for all measures). Significant improvements between scores at 6 months postoperatively and final follow-up were also observed in the Patient-Reported Outcomes Measurement Information System–Physical Function score ( P <.001) and the KOOS Sports and Recreation ( P =.02) and Quality of Life ( P =.02) subscales. There were no complications related to the implant, with zero cases of hardware irritation or hardware removal. There were 4 retears, with 2 patients undergoing subsequent partial meniscectomy. Five patients, who had undergone concomitant procedures, experienced arthrofibrosis and underwent further surgical intervention.

Conclusions

Patients undergoing meniscus repair with knotless, tensionable, all-suture implants showed significantly improved PROs at 6 months after surgery that were maintained through final follow-up, with a 6.35% failure rate. There were zero cases of hardware-related complications, suggesting that knotless, tensionable, all-suture implants are safe and reliable for all-inside meniscus tear repair.

Level of Evidence

Level IV, retrospective therapeutic case series.

Maintaining the health of the menisci is crucial as meniscal tears are among the most common knee injuries. Although likely an underestimation, the incidence rate of meniscal tears in the general population in the United States is estimated to be 61 per 100,000. The incidence rate of meniscal tears in the active-duty military population is estimated to be even greater, at 8.7 per 1,000. Meniscus injuries in younger athletes are often trauma related, whereas degenerative meniscal tears occur more often in male patients and individuals older than 60 years. Involvement in sports, especially those that require frequent kneeling and squatting, increases the risk of meniscal tears.

Although the inside-out approach is typically regarded as the gold standard for meniscal repair, recent advancements in implant technology have led to the increasing popularity of the all-inside technique. ^, Studies comparing outcomes and failure rates after all-inside and inside-out meniscal repair have shown no significant differences in clinical outcomes between the two techniques for the vast majority of tear patterns. ^, In addition, the all-inside approach eliminates the need for an additional incision and/or operating-room assistant. ^, All-inside meniscus repair is known to reduce operative time (which may ultimately result in a more cost-effective procedure despite the cost of the implants) and to possibly decrease rates of neurovascular injury. ^,

A recent biomechanical study has shown that all-inside meniscus repair using all-suture anchors (FiberStitch; Arthrex, Naples, FL) reveals increased primary fixation strength, resistance to gap formation, and failure load when compared with all-inside PEEK (polyether ether ketone) anchors or inside-out repair techniques. The all-inside soft anchor repair devices may avoid difficulties encountered with the bulkier PEEK anchors while producing less gapping and higher failure loads, with results comparable to or better than those of traditional repair devices. Additional studies further support the superiority of all-inside all-suture devices over PEEK anchors and traditional inside-out suture repair in biomechanical experiments. ^, As with any device, biomechanical data are paramount to ensuring the implant is acceptable from a strength and stability perspective. Clinical data are equally or more important, including short-term data, which help to determine the safety profile and early outcomes of the implant in practical application.

The purpose of this study was to evaluate short-term patient-reported outcomes (PROs), complications, and reoperations after all-inside meniscus repair using an all-suture implant. We hypothesized that patients would report improved subjective clinical outcomes compared with their baseline values and would have low rates of reinjuries, complications, and reoperations.

Methods

This study was approved by our institutional review board. Patients who underwent all-inside meniscus repair performed by the senior author (R.M.F.) between November 2019 and December 2023 were identified from an institutional database using Current Procedural Terminology codes 29882 and 29883. A chart review was performed to ensure that patients were included in the study population if they (1) were aged between 18 and 89 years, (2) received a formal diagnosis of a meniscus tear, and (3) were treated surgically with all-inside meniscus repair using the FiberStitch implant. Patients were not excluded if the meniscus repair used additional fixation materials, such as SutureTape (Arthrex), or if they underwent concomitant procedures (e.g., anterior cruciate ligament [ACL] reconstruction [ACLR] or partial meniscectomy). Patients were excluded if they were treated with an implant other than the FiberStitch; the repair technique on the same knee included meniscus root repair, ramp repair, or inside-out or outside-in approaches; they had a diagnosis of a connective tissue disorder; they did not complete at least one postoperative outcome survey at a minimum of 6 months after surgery; or their electronic medical records were unavailable for review.

After eligible patients were identified, data from our institution’s prospectively maintained sports medicine outcomes registry were reviewed. All patients had provided informed consent prior to their enrollment into the data registry. Analyzed variables from the data registry included patients’ responses to several surveys including the visual analog scale (VAS) for pain; Knee Single Assessment Numerical Evaluation (SANE); Patient-Reported Outcomes Measurement Information System–Physical Function (PROMIS-PF); Patient-Reported Outcomes Measurement Information System–Pain Interference (PROMIS-PI); and Knee Injury and Osteoarthritis Outcome Score (KOOS) Pain, Symptoms, Activities of Daily Living (ADL), Sports and Recreation, and Quality of Life (QOL) subscales. The VAS score is a measure of pain intensity on a scale from 0 to 10, where 0 means no pain and 10 corresponds to the worst pain imaginable. The Knee SANE is a measure of what percentage of normal a patient would rate his or her current knee function. The PROMIS-PF is a measure from 0 to 100 of how well a patient believes he or she can perform daily physical activities such as housework, walking, and standing, with a score of 100 meaning the patient is able to perform all daily physical activities without issue. The PROMIS-PI is a measure from 0 to 100 of how much a patient’s knee function interferes with his or her ability to perform and enjoy a variety of physical and social activities, with a lower score corresponding to less negative interference. The KOOS, comprising Pain, Symptoms, ADL, Sports and Recreation, and QOL subscales, is a measure from 0 to 100 of a patient’s pain at rest and during activity, presence and severity of knee symptoms such as swelling and limited range of motion, level of difficulty when completing activities of daily living such as rising from sitting, level of difficulty when performing sports activities, and impact of the patient’s symptoms on his or her quality of life, where a score of 100 indicates no pain, symptoms, or difficulty and a high quality of life.

Patients with missing postoperative outcome surveys were contacted via email and/or text reminders followed by a phone call to obtain information on their current status. Reviews of electronic medical records were also performed to obtain information such as patients’ demographic characteristics, tear location and pattern, concomitant procedures, number of implants, previous and subsequent surgical procedures on the operative limb, and tobacco status, as well as any other relevant medical conditions. Failure was defined as the return of clinical symptoms correlated with a retear of the patient’s meniscus repair as diagnosed on magnetic resonance imaging (MRI).

Surgical Technique

The patient was placed on the operating table in the supine position, a tourniquet was applied to the operative thigh, the extremity was prepared and draped in standard fashion, a timeout was performed, and general anesthesia was induced. The exact surgical approach depended on the procedure(s) being performed. For isolated meniscus repairs, the procedure was initiated with a diagnostic arthroscopy via standard anteromedial and anterolateral portals followed by meniscus repair. If concurrent ACL repair or reconstruction surgery was performed, typically the autograft was harvested first, the femoral tunnel was drilled with the knee in hyperflexion, and then the meniscus was repaired. For medial meniscus repairs, the knee was held in extension-valgus, and when deemed necessary for safe access to the medial compartment by the senior author, the proximal medial collateral ligament underwent trephination with a spinal needle to improve visualization and access to the medial compartment. For lateral meniscus repairs, the knee was maintained in a figure-of-4 position.

For all cases, to optimize the biologic healing potential for the repair, a meniscal rasp was used along the meniscal tear site as well as the capsular tissue. After meniscus and capsule preparation, a meniscus sled was used to protect the articular cartilage, and the meniscus repair device was inserted into the working portal and advanced through the meniscus and capsular tissue before deploying the first all-suture anchor. The handle of the device was then pulled back slightly, without removing it from the compartment, and translated to an appropriate site to deploy the second all-suture anchor. With both anchors deployed, the inserter was removed from the joint, and a probe was used to tension the remaining suture loop, reduce the meniscus, and secure the implant. Finally, the arthroscopic knot pusher was introduced into the joint to cut the remaining suture limb. After each suture placement, a probe was used to pull on the meniscus and assess the stability of the repair. Additional sutures were placed as many times as necessary to fully repair the meniscus tear ( Fig 1 ). If concomitant ACLR was not performed, a microfracture awl was used to create several bone-marrow venting holes along the lateral aspect of the intercondylar notch, just anterior to the ACL, to improve the biology for repair. Biologic augmentation with platelet-rich plasma was also used on a case-by-case basis.

Image, AltText currently not available — Fig 1

Postoperative rehabilitation was dependent on the specific procedure(s) performed as well as the meniscus tear pattern. All patients were placed in a total range-of-motion (TROM) knee brace. Patients with meniscus tears of very poor quality or those with a radial tear pattern were limited to toe-touch weight-bearing for the first 4 weeks, followed by 50% weight-bearing until week 6. Patients with more stable tear patterns, such as vertical tears, were allowed weight-bearing as tolerated as long as any concomitant procedures did not require protected weight-bearing. Although early range of motion was permitted for all patients regardless of tear pattern, weight-bearing in flexion beyond 90° was not permitted until 3 months after surgery. A gradual return to athletic activities as guided by the physical therapist was typically permitted after 4 to 5 months for isolated meniscus repair and after approximately 9 months for meniscus repair performed with ACL repair or reconstruction surgery.

Statistical Analysis

To compare the difference between PRO values at baseline and those at each postoperative time point, after normality of the distribution was confirmed, paired t tests were performed on complete cases (i.e., patients who had both a baseline value and a postoperative time point value for a given patient-reported outcome measure [PROM]) using the Bonferroni correction to minimize type I errors. Then, linear mixed models were used to evaluate the trends in the PROs over time, as well as the trends of the PROs on baseline scores; patient sex, age, and body mass index (BMI); concomitant ACLR status; and number of implants. These models controlled for the effects of respective baseline PRO measurements, patient age and sex, tear pattern, meniscus tear laterality, number of implants, number of prior surgical procedures, and presence of concomitant ACLR. Random effects of patient and time were considered to account for multiple measurements per patient over time and ensure proper estimation of fixed effects. For interpretability, analysis-of-variance tables were constructed from the linear mixed models to elucidate the effects of different variables on the PROs. When the P value for a categorical variable was significant ( P <.05) in the analysis-of-variance table, an estimated marginal means table was computed to evaluate all the pair-wise comparisons for the respective categorical variable. The P values were adjusted for multiple comparisons using the Tukey P value adjustment for multiple comparisons. All statistical analyses were performed using R software (version 4.3.2; The R Foundation for Statistical Computing, Vienna, Austria). P <.05 indicated statistical significance, and values smaller than.001 are reported as “ P <.001.”

Results

Patient Characteristics

A total of 168 patients underwent meniscus repair (for any tear pattern, with any technique or implant) performed by the senior author between November 2019 and December 2023. After a thorough chart review, 78 patients were excluded because they underwent meniscus repair with a different technique and/or implant, 23 had not completed at least one postoperative outcome survey at a minimum of 6 months after surgery and were unreachable after multiple attempts at contact, and 4 had undergone concomitant meniscus root repair in the same knee. Thus, 63 patients were found to be eligible and were included in the analysis. Characteristics of the study population are described in Table 1 . The minimum length of follow-up was 7.33 months (mean, 16.32 months; range, 7.33-43.82 months). Patients had undergone 0 to 3 surgical procedures on the operative limb prior to the meniscus repair, with the most common previous procedure being ACLR. In terms of meniscus tear patterns, vertical tears were most common (53.97%), and most of the tears occurred in the medial meniscus (61.90%). Concomitant ACLR was performed in 65.08% of cases, most often using quadriceps tendon autograft. Other types of concomitant procedures included synovectomy (n = 10, 15.87%); chondroplasty (n = 10, 15.87%); partial meniscectomy (n = 8, 12.63%); lateral extra-articular tenodesis (n = 6, 9.52%); loose body removal (n = 3, 4.76%); ACL repair (n = 3, 4.76%); collateral ligament repair (n = 3, 4.76%); tibial spine open reduction and internal fixation (ORIF, n = 2, 3.17%); open removal of hardware (n = 1, 1.59%); intra-articular debridement (n = 2, 3.17%); parameniscal cyst decompression (n = 1, 1.59%); patellar abrasion arthroplasty (n = 1, 1.59%); medial patellofemoral ligament reconstruction with semitendinosus allograft (n = 1, 1.59%); and saphenous nerve exploration, neurolysis, and resection (n = 1, 1.59%). In 15 patients (23.81%), bone-marrow venting of the intercondylar notch was performed. On average, patients were treated with 2.87 ± 1.48 FiberStitch implants. Eight patients (12.70%) were also treated using SutureTape (range, 1-7 implants; for side-to-side repair) in conjunction with the FiberStitch implant(s).

Table 1

Patient Characteristics

Characteristic	Data (N = 63)
Age at surgery, yr	31.63 ± 9.58
Sex
Female	38 (60.32)
Male	25 (39.68)
BMI	25.77 ± 4.04
Duration of symptoms, mo	5.35 ± 8.34
Tear pattern
Bucket handle	13 (20.63)
Complex	9 (14.29)
Horizontal cleavage	1 (1.59)
Oblique	3 (4.76)
Vertical	34 (53.97)
Vertical oblique	3 (4.76)
Meniscus tear laterality
Bilateral	4 (6.35)
Lateral	20 (31.75)
Medial	39 (61.90)
No. of implants used	2.87 ± 1.48
No. of prior surgical procedures on operative limb	0.06 ± 0.40
Concomitant ACLR
No	22 (34.92)
Yes
BPTB allograft	4 (6.35)
BPTB autograft	14 (22.22)
QT autograft	23 (36.51)
Intraoperative PRP injection
Yes	4 (6.35)
No	59 (93.65)