Radiologic and Clinical Analysis of Posterior Medial Meniscal Root Tears: A Comparative Study of All-Suture Anchor and Transtibial Pullout Techniques

Abstract

Background:

Posterior medial meniscal root (PMMR) tears drastically alter knee biomechanics and reduce degenerative risk from a functional meniscectomy. While transtibial pullout (TTP) is a common repair technique, all-suture anchor (ASA) repair alternatively offers a tunnel-less repair construct. This study aimed to compare the radiologic and clinical outcomes of ASA versus TTP repair techniques in patients with PMMR tears.

Hypothesis:

The ASA technique would yield superior outcomes compared to the conventional TTP method.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This ambidirectional cohort study analyzed patients who underwent repair for isolated PMMR tears between 2018 and 2024. Participants were divided into the ASA and TTP groups with a 1-year follow-up. Radiologic evaluation included magnetic resonance imaging at 9 months and weightbearing radiographs at 1 year postoperatively to assess medial meniscal extrusion (MME), healing status, and cartilage progression according to the International Cartilage Repair Society grading system. Clinical outcomes were assessed concurrently using the International Knee Documentation Committee (IKDC) scores.

Results:

The final cohort comprised 36 patients (12 ASAs, 24 TTPs) with comparable baseline characteristics. Radiologically, mean postoperative MME increased in both groups (ASA: 3.63 ± 0.82 mm; TTP: 4.32 ± 1.24 mm), although the difference between groups was not statistically significant (P = .054). Similarly, no significant differences were observed regarding meniscal healing between groups (87.5% vs 66.7%; P = .297) or osteoarthritic cartilage progression. Clinically, both groups achieved significant postoperative IKDC score improvements (P < .05); however, mean improvements were comparable between ASA (20.1) and TTP (20.7) cohorts (P = .859).

Conclusion:

Both ASA and TTP techniques significantly improve functional outcomes for repairing PMMR tears with comparable clinical efficacy. While both groups experienced postoperative meniscal extrusion, the ASA technique showed a trend toward better extrusion control, without significant differences in healing rates or osteoarthritic progression. These findings suggest that ASA repair is a viable alternative to the transtibial pullout method.

The meniscus is integral to knee joint homeostasis, ⁹ functioning as a secondary stabilizer and shock absorber that transmits approximately 50% of weightbearing load during gait and up to 99% during knee flexion. ²³ From a biomechanical perspective, the meniscal roots contain fibrocartilage at the tibial insertion, which converts axial compression into circumferential hoop stress. ⁴ This mechanism prevents meniscal extrusion and ensures physiological load distribution. However, posterior medial meniscal root (PMMR) tears functionally decouple this attachment, resulting in biomechanical consequences equivalent to a total meniscectomy. ¹ Although PMMR tears were historically underdiagnosed due to their subtle clinical presentation, early recognition has become imperative ²⁵ ; untreated root discontinuity precipitates rapid articular cartilage degeneration and the progression of advanced osteoarthritis. ⁸

To avert this degenerative cascade, surgical restoration is recommended. The transtibial pullout (TTP) technique has served as the conventional procedure for PMMR repair ⁸ and is favored for its ability to restore tibiofemoral contact areas. ²⁴ However, the TTP construct is susceptible to the “bungee effect,” wherein the distance between the fixation button and the meniscal root leads to construct micromotion, potential suture abrasion, and undesirable elongation. ¹⁶ In response to these drawbacks, the all-suture anchor (ASA) technique was proposed to directly secure the root at its anatomical footprint. The ASA technique also shortened the fixation construct, thereby minimizing micromotion and maximizing biomechanical pullout strength. ⁵

Given the distinct biomechanical profiles of these 2 repair strategies, ⁵ it is necessary to validate whether the theoretical advantages of anchor fixation translate to clinical practice. The primary objective of this study was to compare the radiologic and clinical outcomes of PMMR tears treated with either the TTP technique or the ASA technique. We hypothesized that the ASA technique would yield superior outcomes compared with the conventional TTP method.

Methods

Patient Selection and Study Design

This ambidirectional cohort study was conducted at Ramathibodi Hospital, Mahidol University, from April 2019 to June 2024, in accordance with the Declaration of Helsinki and with institutional review board approval (COA No. MURA2023/626). Written informed consent was obtained from all participants. The study cohort of 36 patients was divided equally into retrospective and prospective phases (n = 18 each), with the retrospective phase comprising 9 ASA and 9 TTP cases. In contrast, the prospective phase comprised 3 ASA and 15 TTP cases aged >40 years who underwent arthroscopic repair of an isolated complete PMMR tear, performed by 3 fellowship-trained sports medicine surgeons (N.S., C.L., and C.V.). To ensure procedural proficiency, each of the 3 participating surgeons utilized their preferred technique exclusively. One surgeon performed only ASA repairs, while the other 2 performed only TTP repairs. All operative protocols and postoperative rehabilitation remained standardized across both cohorts.

Inclusion criteria consisted of patients with PMMR tears confirmed by magnetic resonance imaging (MRI) and symptom onset within the past 6 months. Patients were excluded if they presented with advanced osteoarthritis (Kellgren-Lawrence grade ≥ 3, varus malalignment ≥ 5°, body mass index (BMI) ≥ 30 kg/m²), or concomitant pathology, such as ligamentous instability or segmental meniscal tears. Additionally, a history of knee surgery, infection, rheumatologic disease, or inability to complete the minimum 1-year follow-up was excluded (Figure 1).

Figure 1.

Study flow diagram. A total of 44 patients were assessed, with 8 excluded (6 due to BMI, 2 for incomplete data). The final cohort of 36 patients was divided into retrospective (n = 18; 9 ASA, 9 TTP) and prospective (n = 18; 3 ASA, 15 TTP) phases. ASA, all-suture anchor; BMI, body mass index; TTP, transtibial pullout.

Surgical Setup and Approach

The patients received combined general and regional anesthesia (adductor canal block). They were positioned supine with a tourniquet applied to the proximal thigh. Diagnostic arthroscopy was conducted via standard anterolateral and anteromedial portals. The pie crust procedure was performed by using an 18-G needle to release the medial collateral ligament by applying valgus force to the knee. An optimal visualization was created to prevent iatrogenic cartilage scuffing. PMMR tear was identified and debrided to a stable margin.

ASA Technique

This technique was adapted from the original method proposed by Balke et al. ³ The 2.8-mm Y-Knot RC anchors (CONMED Linvatec) were used as implants. The Acufex (Smith & Nephew) tibial aiming guide was used to establish a tibial tunnel, which was drilled from the anterior cortex with a 2.4-mm beath pin. The anchor was marked 1.5 cm from the tip and unloaded from the handle. It was shuttled into the tibial tunnel via an 18-G spinal needle equipped with a looped number 2 Ethibond (Ethicon). The anchor was pulled down to the marker length, then tensioned retrogradely with a knot pusher to achieve the optimal orientation. This maneuver ensured that the suture ball was firmly deployed underneath the tibial plateau cortex. The medial meniscal substance was bitten 3 mm from the medial edge using FIRSTPASS MINI (Smith & Nephew). A Modified Mason-Allen configuration was performed and tied with 5 square knots (Figure 2).

Figure 2.

Key steps of the ASA repair technique. (A) Anchor deployment: an arthroscopic view showing the insertion of the ASA loaded with high-strength sutures directly into the PMMR tibial footprint. (B) Suture passage: 1 limb of the suture is passed vertically through the substance of the detached posterior meniscal root using a suture-shuttling device. (C) Root reduction: tension is applied to the suture limbs, firmly reducing the meniscal root to the prepared bone bed to restore anatomic positioning and hoop tension. (D) Final construction: the final arthroscopic view demonstrated a stable repair of the root to the footprint. ASA, all-suture anchor; PMMR, posterior medial meniscal root.

TTP Technique

The anatomic tibial footprint was decorticated to expose bleeding subchondral bone, thereby enhancing the potential for biological healing. One of the Minitape and Ultratape (Smith & Nephew) was passed 5 mm medial to the torn meniscal edge using a FIRSTPASS MINI suture passer. The tibial tunnel was established using the same protocol as the ASA technique. A 4.0-mm Endobutton drill bit (Smith & Nephew) was advanced from the anteromedial tibial cortex to the anatomic footprint of the meniscal root. The repair utilized a double cinch-stitch configuration. Subsequently, the suture limbs were shuttled through the tibial tunnel, and the meniscal root was repositioned. The construct was stabilized using an Endobutton and secured over the anteromedial tibial cortex with five surgical square knots (Figure 3).

Figure 3.

Key steps of the TTP repair technique. (A) Suture passage: high-strength suture tapes are passed through the detached posterior meniscal root using a suture-passing instrument, creating a cinch stitch configuration. (B) Tibial tunnel creation: an arthroscopic view demonstrating the tip of the guide pin drilling up through the tibial plateau, precisely targeting the center of the anatomical root attachment site using an ACL aiming guide. (C) Suture retrieval: the suture limbs are retrieved and pulled down through the transtibial tunnel, exiting the anterior tibial cortex. (D) Final fixation: The final view showing the sutures tensioned and firmly secured over a cortical button on the anteromedial aspect of the proximal tibia. ACL, anterior cruciate ligament; TTP, transtibial pullout.

Rehabilitation Protocol

Postoperative rehabilitation was the same for all participants to ensure consistency and was unrelated to the fixation technique. All patients were scheduled for follow-up evaluation at 2, 4, and 6 weeks, then at 3, 6, 9, and 12 months postoperatively. For the first 6 weeks postoperatively, patients remained nonweightbearing and used a protective knee brace. Range of motion was managed sequentially: flexion was limited to 0° to 30° for the first 2 weeks, then increased to 60° and 90° at 2-week intervals. During this immobilization phase, patients performed isometric quadriceps and hamstring strengthening exercises. At 6 weeks, flexion was allowed to progress from 0° to 120°. Weightbearing was introduced at this stage, gradually from partial to full weightbearing by the eighth week. Although full daily activities were permitted by the third postoperative month, high-impact sports remained restricted until at least 6 months.

Radiologic Assessment

Evaluations were conducted using nonweightbearing MRI scans obtained at a mean postoperative follow-up of 9 months. Image acquisition MRI studies of the knee were performed with the patient in the supine position using 2 different whole-body MRI systems: a 3T and a 1.5T (Philips Healthcare), distributed as follows: ASA group (75% 1.5T; 25% 3T) and TTP group (91.6% 1.5T; 8.4% 3T). Scanner assignment was based solely on availability. Both systems utilized a dedicated 16-channel knee coil for signal reception. The imaging protocol was standardized across both scanners and consisted of sagittal T2-weighted (T2w), sagittal proton density fat-suppressed (PDFS), coronal T1-weighted (T1w), and coronal PDFS sequences acquired using a fast spin echo technique. The field of view (FOV) was maintained at 160 × 160 mm, with a section thickness of 3 mm and an interslice gap of 0.3 to 1 mm.

Medial Meniscal Extrusion

Medial meniscal extrusion (MME) was quantified on coronal images utilizing the validated “tibial spine cut” method, identified by the slice displaying the most prominent tibial eminence. Extrusion was defined as the perpendicular distance (in mm) from the vertical margin of the medial tibial plateau to the peripheral edge of the medial meniscus at the same cut of the medial collateral ligament ¹³ (Figure 4). Two independent, blinded observers (P.W., and N.C.) performed all measurements. Interobserver reliability was good, with intraclass correlation coefficients >0.80.

Figure 4.

(A) Preoperative mid-coronal T2FS MRI signaling medial meniscal extrusion of 4.25 mm. (B) Corresponding postoperative image showing that the extrusion decreased to 3.18 mm. MRI, magnetic resonance imaging; T2FS, T2-weighted fat-suppressed.

Meniscal Healing

Healing status was stratified into 3 categories—complete, partial, or nonhealing—based on criteria adapted from Kim et al. ¹⁷ Complete healing was defined as the presence of continuous low-signal-intensity tissue spanning the repair site with no visible defects. Partial healing was characterized by bridging tissue that nevertheless exhibited residual high-signal intensity or incomplete continuity. Nonhealing was identified by a persistent discontinuity or a total absence of bridging tissue at the interface (Figure 5).

Figure 5.

Stratification of meniscal healing. (A) Complete healing is defined by continuous low-signal tissue across the repair. (B) Partial healing, showing bridging tissue with residual high signal or incomplete continuity. (C) Nonhealing, characterized by persistent discontinuity or a lack of bridging tissue.

Both plain radiography and MRI were used to evaluate osteoarthritis. Preoperative and 1-year postoperative weightbearing radiographs were analyzed according to the Kellgren-Lawrence grading scale. ¹⁸ Concurrently, articular cartilage integrity was assessed on MRI using the International Cartilage Repair Society (ICRS) classification system. ¹² These MRI evaluations encompassed 3 specific anatomical regions—the medial femoral condyle, the lateral femoral condyle, and the patellofemoral joint.

Clinical Assessment

Patients with a 1-year follow-up underwent functional evaluation at their final postoperative visit. Assessments were administered by an independent observer (P.W.) unaffiliated with the surgical team, thereby maintaining blinding to treatment details and outcomes. Patient-reported outcomes were quantified using the International Knee Documentation Committee (IKDC) subjective knee form. ²⁰

Statistical Analysis and Sample Size Calculation

All statistical analyses and sample size estimations were performed using STATA, Version 17 (StataCorp). An a priori power analysis was conducted to evaluate the superiority of the ASA technique in reducing medial meniscal extrusion, based on a previous study, ²⁸ assuming a mean difference of 38.4%. Applying a 2:1 allocation ratio (TTP: ASA) to reflect surgical practice, 80% power, and a 2-tailed alpha of .05, the calculation required a minimum of 36 patients (24 TTP and 12 ASA) to account for a 20% potential dropout rate. Data normality was assessed via the Shapiro-Wilk test. Continuous variables were compared using the Student t test for parametric data (reported as mean ± SD) and the Mann-Whitney U test for nonparametric data (reported as median [interquartile range]). Pre- and postoperative changes were evaluated using the Wilcoxon signed-rank test. Categorical variables were analyzed using the Pearson chi-square or the Fisher exact tests as appropriate, with statistical significance defined as P < .05.

Results

This study utilized an ambidirectional design, comprising 18 retrospective and 18 prospective patients for a total of 36 patients. Participants were stratified by surgical technique into the ASA group (n = 12) and the TTP group (n = 24). Assessment of baseline descriptive data revealed no statistically significant differences between the cohorts, ensuring comparability. The mean age was 60.75 ± 11.54 years in the ASA group and 59.16 ± 6.74 years in the TTP group (P = .667). Although the TTP group comprised a higher proportion of female patients (87.5%) than the ASA group (58.33%), this difference was not statistically significant (P = .086). Furthermore, there were no significant disparities regarding BMI, preoperative limb alignment, onset of injury to surgery, or the prevalence of underlying comorbidities such as diabetes mellitus and hypertension (P > .05 for all comparisons) (Table 1).

Table 1.

Baseline Patient Characteristics ^a

Variable	ASA Group n = 12	TTP Group n = 24	P
Patient characteristics
Age, year	60.75 ± 11.54	59.16 ± 6.74	.667
Sex			.086
Male	5 (41.67)	3 (12.5)
Female	7 (58.33)	21 (87.5)
Height, cm	158.41 ± 5.88	156 ± 5.60	.263
Weight, kg	63.94 ± 9.46	62.7 ± 13.67	.932
BMI, kg/m2	25.14 ± 3.01	26.32 ± 3.07	.284
Affected side			.499
Right	6 (50)	9 (37.5)
Left	6 (50)	15 (62.5)
Time to surgery, months	4.66 ± 1.43	4.37 ± 1.68	.612
Length of postop clinical follow-up, months	13.42 ± 1	13.54 ± 1.93	.835
Underlying disease
Diabetes mellitus	4 (33.3)	6 (25)	.700
Hypertension	3 (25)	8 (33.3)	.715
Dyslipidemia	6 (50)	8 (33.3)	.471
Hyperthyroid	0 (0)	3 (12.5)	.536
Radiologic characteristics
Length of MRI follow-up, months	9.44 ± 1.81	8.79 ± 1.03	.231
Length of weightbearing film follow-up, months	13.42 ± 1	13.54 ± 1.93	.835
Knee valgus alignment, deg	3.83 ± 2.12	3.25 ± 2.31	.231
Lateral distal femoral angle, deg	81.42 ± 1.51	81.75 ± 1.33	.501
Medial proximal tibial angle, deg	85.42 ± 0.90	85.79 ± 1.53	.263

^aData are presented as mean ± SD or n (%). ASA, all-suture anchor; BMI, body mass index; MRI, magnetic resonance imaging; TTP, transtibial pullout.

The radiologic evaluation at final follow-up revealed comparable outcomes between the 2 surgical techniques, although notable trends were observed regarding meniscal positioning. Preoperative MME was similar between groups (3.69 ± 0.79 mm vs 3.85 ± 1.03 mm; P = .653). Postoperatively, the TTP group demonstrated a mean meniscal extrusion of 4.32 ± 1.24 mm, compared with 3.63 ± 0.82 mm in the ASA group. This difference did not reach statistical significance (P = .054). Meniscal root healing rates were statistically equivalent (P = .342), with complete healing observed in 25% of ASA patients and 33.3% of TTP patients (Table 2). Furthermore, no significant differences were found in the progression of osteoarthritis, as measured by both the Kellgren-Lawrence grading system (P = .377 postoperatively) and ICRS cartilage scores across the medial, lateral, and patellofemoral compartments (P > .05 for all) (Table 3).

Table 2.

Comparative Analysis of Medial Meniscal Extrusion and Healing Status ^a

Variable	ASA Group n = 12	TTP Group n = 24)	P
Extrusion, mm
Preoperative	3.69 ± 0.79	3.85 ± 1.03	.653
Postoperative	3.63 ± 0.82	4.32 ± 1.24	.054
Postoperative root healing status			.342
Complete	3 (25)	8 (33.3)
Partial	5 (41.7)	13 (54.2)
None	4 (33.3)	3 (12.5)

^aData are presented as mean ± SD or n (%). ASA, all-suture anchor; TTP, transtibial pullout.

Table 3.

Comparative Analysis of Radiologic Findings on Pre- and Postoperative MRI and Weightbearing Radiographs ^a

Variable	ASA Group n = 12			TTP Group n = 24
	Preop	Postop	P	Preop	Postop	P
MRI analysis
Articular cartilage integrity by ICRS
Medial femoral condyle grade			.878			.827
0	0 (0)	0 (0)		1 (4.2)	0 (0)
1	0 (0)	0 (0)		1 (4.2)	1 (4.2)
2	3 (25)	1 (8.3)		7 (29.1)	2 (8.3)
3	2 (16.7)	2 (16.7)		6 (25)	7 (29.1)
4	7 (58.3)	9 (75)		9 (37.5)	14 (58.3)
Lateral femoral condyle grade			.282			.23
0	2 (16.7)	1 (8.3)		12 (50)	6 (25)
1	3 (25)	2 (16.7)		2 (8.3)	3 (12.5)
2	4 (33.3)	3 (25)		6 (25)	11 (45.8)
3	2 (16.7)	5 (41.7)		3 (12.5)	3 (12.5)
4	1 (8.3)	1 (8.3)		1 (4.2)	1 (4.2)
Patellofemoral joint grade			.816			.8
0	0 (0)	0 (0)		3 (12.5)	1 (4.2)
1	3 (25)	1 (8.3)		4 (16.7)	14 (16.7)
2	2 (16.7)	2 (16.7)		3 (12.5)	1 (4.2)
3	1 (8.3)	2 (16.7)		4 (16.7)	5 (20.8)
4	6 (50)	7 (58.3)		10 (41.7)	13 (54.2)
Weightbearing radiographs analysis
Kellgren-Lawrence grade			.313			.377
0	0 (0)	0 (0)		3 (12.5)	0 (0)
1	5 (41.7)	0 (0)		14 (58.3)	4 (16.7)
2	7 (58.3)	8 (66.7)		7 (29.1)	15 (62.5)
3	0 (0)	4 (33.3)		0 (0)	5 (20.8)
4	0 (0)	0 (0)		0 (0)	0 (0)

^aData are presented as the number of patients with that condition (percentage). ASA, all-suture anchor; MRI, magnetic resonance imaging; Postop, postoperative; Preop, preoperative; TTP, transtibial pullout.

Analysis of postoperative changes revealed distinct trends in meniscal extrusion patterns and the progression of osteoarthritis. Regarding MME, the ASA group demonstrated a favorable tendency with 58.3% exhibiting decreased extrusion, compared with only 29.2% in the TTP group. Conversely, the majority of those who underwent TTP (70.8%) experienced an increase in extrusion, although this inter-group difference did not reach statistical significance (P = .148). A similar pattern was observed in the medial femoral condyle, where cartilage progression was less frequent in the ASA group (25%) compared with the TTP group (45.8%) (P = .227). No significant differences were found in the lateral compartment or patellofemoral joint (P > .05). Radiographic progression (Kellgren-Lawrence grade) occurred in half of the ASA cohort (50%) versus two-thirds of the TTP cohort (66.7%) (P = .334) (Table 4).

Table 4.

Postoperative Change of Medial Meniscal Extrusion and Progression of Osteoarthritis Change ^a

Variable	ASA Group (n = 12)	TTP Group n = 24	P
MRI analysis
Medial meniscus extrusion			.148
Increase	5 (41.7)	17 (70.8)
Decrease	7 (58.3)	7 (29.2)
Articular cartilage by ICRS classification
Medial femoral condyle			.227
Progression	3 (25)	11 (45.8)
No progression	9 (75)	13 (54.2)
Lateral femoral condyle			.798
Progression	4 (33.3)	7 (29.2)
No progression	8 (66.7)	17 (70.8)
Patellofemoral joint			.806
Progression	4 (33.3)	9 (37.5)
No progression	8 (66.7)	15 (62.5)
Weightbearing radiographs analysis
Kellgren-Lawrence grade			.334
Progression	6 (50)	16 (66.7)
No progression	6 (50)	8 (33.3)

^aData are presented as the number of patients with that condition (percentage). ASA, all-suture anchor; ICRS, International Cartilage Regeneration & Joint Preservation Society; MRI, magnetic resonance imaging; TTP, transtibial pullout.

While the ASA technique showed a trend toward superior meniscal extrusion control compared with the TTP technique, this radiological observation did not translate into a significant difference in functional performance. From a patient-reported perspective, both surgical interventions delivered substantial clinical benefits that far exceeded the threshold for meaningful recovery. Final IKDC scores remained nearly indistinguishable between the ASA and TTP groups (57.4 vs 57.9; P = .919), indicating that both techniques are equally effective in facilitating subjective functional improvement despite variations in extrusion control. Despite the advanced degenerative changes noted radiologically, patients in both groups reported a significant leap in functional status (P < .01). Importantly, the mean improvement of approximately 20 points in both cohorts nearly doubled the established minimal clinically important difference of 10.17 points. ² This confirms that the statistical significance translates into tangible real-world relief. The choice of surgical technique did not influence subjective recovery; the All-ASA and TTP methods resulted in nearly indistinguishable final IKDC scores (57.4 vs 57.9; P = .919), indicating that successful correction of the root tears improved knee function regardless of the specific fixation device used (Table 5). Multivariable regression analysis indicated that a higher BMI was independently associated with reduced improvement in IKDC scores (β = −2.20; 95% CI, −4.37 to −0.22; P = .048), whereas sex exerted no significant effect.

Table 5.

Patient-Reported Outcomes ^a

Functional assessment score	ASA Group n = 12	TTP Group n = 24	P
Preop IKDC	38.2 ± 12.7	37.1 ± 12.2	.798
Postop IKDC	57.4 ± 15.2	57.9 ± 14.5	.919
Mean change	20.1 (12.1, 28.2)	20.7 (11.5, 30.45)	.859
P	<.001	<.001

^aData are presented as mean ± SD or mean changes [IQR]. Boldface P values indicate statistical significance (P≤ .001). ASA, all-suture anchor; IKDC, International Knee Documentation Committee; IQR, interquartile range; TTP, transtibial pullout.

Discussion

The importance of this study was that, although the ASA technique showed a radiological trend toward superior control of meniscal extrusion compared with the TTP technique, it did not yield any significant difference in functional outcomes. Both techniques demonstrated similar effectiveness, with acceptable healing rates and comparable short-term outcomes. Our findings did not support the hypothesis that ASA would yield superior functional outcomes to TTP. Despite ASA's theoretical advantages in controlling meniscal extrusion, clinical recovery was comparable between the 2 techniques.

To understand this clinical equivalence, the established biomechanical rationale underlying these procedures must first be considered. Biomechanical evidence over the past 2 decades consistently confirms that surgical repair of the meniscal root restores superior joint mechanics compared with nonoperative management.^1,5,24 Conservative treatment is now primarily reserved for patients who are poor surgical candidates due to significant comorbidities. ²¹ While indications have expanded, the ideal candidates remain young, active individuals without significant osteoarthritis or malalignment. Conversely, factors such as advanced age, high BMI, and prolonged symptom duration are recognized as poor prognostic indicators. ⁶

MME is the most challenging prognostic factor to address among these. It remains a critical prognostic factor for osteoarthritic progression and repair failure.^27,29 A major clinical challenge is that neither ASA nor TTP techniques consistently reverse preoperative extrusion. ¹¹ In this cohort, persistent MME was observed independent of the repair technique, suggesting that the underlying causes extend beyond the fixation method itself. This persistence is likely driven by the degenerative nature of posterior medial meniscal root tears, which are prevalent in older populations, consistent with our demographics.^8,10 Previous studies have demonstrated that patients with root tears exhibit increased meniscal volume and elevated T2 values compared with healthy controls, indicative of intrasubstance tissue degeneration^14,22; if this tissue compromise predates the tears, it may explain why extrusion continues postoperatively. Furthermore, extra-articular factors such as quadriceps insufficiency play a critical role, as adequate muscular load distribution is essential for meniscal containment. ¹⁵ The lack of extrusion reversal, particularly in patients with lower baseline strength, underscores the necessity of aggressive postoperative muscular rehabilitation. Importantly, even if current techniques cannot fully reverse extrusion, meniscal root repair remains clinically justified, as it has been shown to decelerate osteoarthritic progression and offers superior cost-effectiveness compared with conservative management. ⁷

Although MRI analysis serves as a surrogate for structural integrity, the correlation between fixation rigidity and healing quality is complicated. Some authors argued that the ASA technique facilitates a more consolidated biological response due to superior time-zero fixation.^5,24 However, these data contradict the notion of ASA superiority. We observed comparable healing profiles between the 2 groups, with the TTP technique showing a trend toward higher total healing rates (complete + partial) than the ASA technique (87.5% vs 66.7%). The fact that a significant proportion of these patients fell into the “partial healing” category underscored the challenge of achieving pristine anatomical restoration in chronic tears. Despite partial MRI evidence of healing, patients showed significant clinical and functional improvement, suggesting that partial root integration may be sufficient for functional stability. This phenomenon reinforced the consensus that biological success was multifactorial and likely influenced more by rehabilitation protocols than by implant choice.

While biological healing is the immediate goal, the long-term objective is the preservation of the joint surface. Although the prevention of osteoarthritis remains a cornerstone of meniscal root repair, absolute cartilage preservation cannot be guaranteed. Current literature suggests that ASA and TTP techniques were equally effective at slowing Kellgren-Lawrence progression, with a minimal incidence of progression to grade 3 osteoarthritis in comparative cohorts.^8,16,19 However, slowing does not equate to stopping. Even with successful symptomatic relief, chondral lesions progress in roughly 25% of ASA cases. ²⁶ This aligns with our own cohort's findings. Although no patients required arthroplasty, this study observed early radiological signs of cartilage deterioration. This disconnect suggests that while root repair effectively delays joint destruction, it cannot fully restore the knee to a preinjury state, which underscores the need for long-term surveillance.

Despite these radiological caveats, the patient experience remains overwhelmingly positive. Comparative literature validates both anchor-based and TTP repairs as effective interventions with indistinguishable clinical profiles. A previous study found no statistically significant differences in postoperative patient-reported outcomes. ¹⁶ Both techniques reliably improved the patient's function from severe impairment (scores in the 30s) to satisfactory levels (scores in the 70s). This equivalence suggests that in common degenerative root tears, clinical benefit is driven by successful root fixation itself, with the choice of fixation technique a matter of surgeon preference rather than clinical superiority. However, while functional scores improved significantly from baseline, final absolute IKDC scores remained relatively modest. This ceiling effect likely reflects the underlying degenerative state of the joint, as evidenced by the continued progression of meniscal extrusion and radiologically observed osteoarthritic changes in both cohorts. Ultimately, these findings suggest that while root repair provides meaningful symptomatic relief, it may not fully reverse or halt the preexisting degenerative process inherent in this population.

This study has several limitations. First, the nonrandomized, ambidirectional design introduced potential selection bias, although this was partially mitigated by the inclusion of a prospective cohort for half of the study population. Second, the focus on isolated meniscal root repairs limits the generalizability of our findings; however, this approach was crucial to eliminate confounding variables associated with concomitant procedures. Third, our evaluation of healing and cartilage deterioration relied solely on MRI. While second-look arthroscopy remains the gold standard for assessing healing, it was not performed due to ethical considerations regarding invasive procedures in asymptomatic or successfully treated patients. Fourth, our 2:1 group-size imbalance and the higher proportion of female patients in the TTP group may limit statistical power and introduce selection bias; future research with larger, more balanced cohorts is needed to validate our findings. Fifth, the relatively small sample size means that secondary outcome comparisons may be underpowered and should be interpreted with caution. Sixth, the fact that different surgeons performed the 2 techniques introduces the possibility of performance bias. Finally, while a 1-year follow-up precluded definitive conclusions regarding functional outcome and long-term osteoarthritic progression, extended longitudinal follow-up remains essential to establish the long-term clinical durability and chondroprotective efficacy of these repair techniques.

Conclusion

This comparative analysis demonstrated that both ASA and TTP repairs yield significant and indistinguishable functional improvement. While neither surgical technique fully restored the native meniscal position, persistent extrusion was observed across the majority of the cohort. Future research should prioritize biological enhancement strategies to improve healing rates in this challenging degenerative injury, rather than focusing solely on mechanical fixation.