Comparison of quadriceps and hamstring tendon autograft in primary anterior cruciate ligament reconstruction: A meta-analysis and systematic review of randomized controlled trials

Search strategy

This systematic review was performed and reported in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.^[12,13] A comprehensive literature search was undertaken using MEDLINE, Embase, and Web of Science databases from inception to December 2025. Titles and abstracts retrieved from the database searches were independently screened by two reviewers. Full-text articles of potentially eligible studies were subsequently assessed independently against predefined inclusion and exclusion criteria. Any disagreements were resolved through discussion among all authors until consensus was achieved. Data extraction from eligible studies was performed using a data collection spreadsheet, with accuracy verified by an additional reviewer.

Study eligibility and participant criteria

Eligible studies included RCTs and quasi-randomized studies directly comparing QT autografts with HT autografts for primary ACLR. Studies published in any language were considered eligible, provided an English translation was available at the time of review.

Studies were excluded if they involved ACL repair rather than reconstruction, used allograft tissue, included revision or secondary ACL reconstruction, or involved concomitant meniscal injuries requiring immediate surgical intervention. Studies enrolling patients with inflammatory arthropathies or degenerative knee conditions were also excluded.

Interventions and comparators

The intervention of interest was the use of a QT autograft, with or without a bone block, for primary ACLR. The comparator group included any HT autograft configuration used for primary ACLR, including single-bundle, double-bundle, or quadruple-strand techniques. Studies were eligible regardless of whether a lateral extra-articular tenodesis was performed alongside the primary reconstruction.

Outcome measures

The primary outcome measure was the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation score assessed at final follow-up. The IKDC is a validated patient-reported outcome measure (PROM) evaluating knee symptoms, functional limitations, and activity levels, with lower scores indicating greater impairment.^[14]

Secondary outcomes included additional validated PROMs, objective muscle strength assessments, complication rates, and time to return to previous activity levels. PROMs assessed were the ACL-QOL score,^[15] Knee Injury and Osteoarthritis Outcome Score (KOOS),^[16] Lysholm Knee Score,^[17] Tegner Activity Scale,^[18] Cincinnati Knee Rating System (CKRS),^[19] and Visual Analog Scale (VAS) pain scores.^[20] Objective outcomes included isometric and isokinetic measures of quadriceps and hamstring muscle strength where available. Complications were categorized as harvest-site infection, donor-site morbidity, graft failure, and overall adverse events, including muscle atrophy. Time to return to work and return to sport was also recorded when reported.

Minimal clinically important difference (MCID) values were identified from existing literature to aid clinical interpretation. Reported MCIDs ranged from 9.0 to 9.5 for IKDC scores and 10.0–10.1 for Lysholm scores at 2-year follow-up.^[21,22] An MCID of 1.0 was used for the Tegner Activity Scale based on previous ACL injury studies.^[23]

Risk of bias and quality assessment

Risk of bias for all included randomized studies was assessed using the Cochrane Risk of Bias 2.0 tool.^[24] The overall certainty of evidence and strength of recommendations were evaluated using the grading of recommendations, assessment, development, and evaluations (GRADE) framework.^[25] Two reviewers independently performed the risk of bias and GRADE assessments, with discrepancies resolved through consultation with a third reviewer.

Data synthesis and statistical analysis

A narrative synthesis was initially performed to compare outcomes between QT and HT autografts. Quantitative data for primary and secondary outcomes were summarized in tabular form. Continuous variables were reported as means or medians with corresponding standard deviations or interquartile ranges, while categorical variables were expressed as percentages.

Meta-analysis was conducted using Review Manager (RevMan) software^[26] where outcome data were sufficiently homogeneous. Pooled analyses were performed using a random-effects model with an intention-to-treat approach, incorporating outcomes measured at final follow-up. Mean differences (MD) or odds ratios (OR) with 95% confidence intervals (CI) were calculated as appropriate. Statistical significance was defined as a P < 0.05. Studies reporting outcomes that could not be pooled due to heterogeneity or incompatible reporting were excluded from meta-analysis and discussed qualitatively.

Study selection

The database search across MEDLINE, Embase, and Web of Science identified a total of 2,509 records. Following the removal of 956 duplicate entries and screening of titles and abstracts, 55 articles were retrieved for full-text review. Of these, six studies fulfilled the predefined inclusion criteria and were included in the final analysis [Figure 1].^[27-32]

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Figure 1:

Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 flow diagram.

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Study characteristics

The key characteristics of the included studies are summarized in Table 1.^[27-32] Across all included trials, 426 patients were analyzed, with 213 allocated to the QT autograft group and 213 to the HT autograft group.^[27-32] Four studies specified the use of a QT graft with a patellar bone block and a four-strand HT graft,^[27-30] whereas two studies did not clearly describe the graft preparation technique.^[31,32] Mean participant age ranged from 18.1 ± 3.6 to 28.3 ± 6.2 years in the QT group and from 19.2 ± 3.6 to 32.7 ± 11.4 years in the HT group.

Risk of bias assessment

Risk of bias assessment using the Cochrane Risk of Bias (ROB) 2.0 tool is presented in Figure 2.^[24] All included studies were judged to be at high risk of performance bias, as surgeon blinding to graft choice was not feasible. Three studies reported that patients were aware of their graft allocation.^[27,29,30] The remaining studies did not specify whether patient blinding was implemented.^[28,31,32] One study was deemed to be at high risk of detection bias due to unblinded outcome assessment related to procedure-specific scarring.^[30] Another study was classified as high risk for reporting bias because VAS outcomes were prespecified but not reported.^[32] For two studies, reporting bias could not be adequately assessed due to unavailable study protocols.^[28,31]

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Figure 2:

Risk of bias for all included studies.

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Primary outcome: IKDC score

Five studies reported post-operative IKDC subjective scores.^[27-31] Three studies assessed IKDC outcomes at 24 months,^[27-29] while two reported results at 12 months.^[30,31] Pooled analysis demonstrated no statistically significant difference between QT and HT autografts (MD 0.52, 95% CI −2.40–3.43; five studies, 375 patients; P = 0.73, [Figure 3]). Statistical heterogeneity was low (I² = 40%), and the certainty of evidence was rated as moderate using the GRADE framework [Tables 2 and 3]. The observed MD was well below the reported MCID of 9.0–9.5, indicating no clinically meaningful difference between graft types^[21,22] [Figure 3].

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Figure 3:

(a) Forest plot for post-operative IKDC scores at final follow-up. (b) Funnel plot for post-operative IKDC scores at final follow-up. IKDC: International Knee Documentation Committee. QT: Quadriceps tendon, HT: Hamstring tendon, SD: Standard deviation, CI: Confidence interval.

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Secondary outcomes: PROMs

Patient-reported outcomes are detailed in Table 4.^[27-32] One study did not report any PROMs,^[30] and none of the included trials assessed ACL-QOL scores. KOOS outcomes were reported in only one study, which found no significant differences across any KOOS subscales between QT and HT grafts at 24 months postoperatively.^[29]

Lysholm scores were reported in four studies,^{[27,28,31,32]} none of which demonstrated a significant between-group difference. Three of these studies were eligible for meta-analysis,^[27,28,31] which showed no significant difference favoring either graft (MD −0.55, 95% CI −4.88–3.77, P = 0.80) [Figure 4]. Moderate heterogeneity was observed (I² = 56%), and the certainty of evidence was graded as low [Table 2].

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Figure 4:

(a) Forest plot for post-operative Lysholm scores at final follow-up. (b) Funnel plot for post-operative Lysholm scores at final follow-up. QT: Quadriceps tendon, IV: Inverse variance, HT: Hamstring tendon, SD: Standard deviation, CI: Confidence interval.

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Two studies reported Tegner Activity Scale scores at 24 months.^[27,29] Meta-analysis revealed no difference between groups (MD 0.00, 95% CI −0.39–0.40, P = 0.98) [Figure 5]. Heterogeneity was absent (I² = 0%), and the certainty of evidence was moderate [Table 2].

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Figure 5:

(a) Forest plot for post-operative Tegner activity scale at final follow-up. (b) Funnel plot for post-operative Tegner activity scale at final follow-up. QT: Quadriceps tendon, IV: Inverse variance, HT: Hamstring tendon, SD: Standard deviation, CI: Confidence interval.

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Only one study assessed CKRS scores, reporting no significant difference at 24 months.^[27] This study also found no between-group differences in VAS scores for knee pain or graft-site pain at the same time point.^[27] Another study reported no significant VAS difference at 12 months.^[31] Due to substantial variation in pain assessment timing and outcome definitions, these data were not suitable for quantitative pooling.

Secondary outcomes: Objective Muscle Strength

Objective muscle strength outcomes were reported in two studies.^[27,30] Ebert et al.^[27] found significantly greater quadriceps limb symmetry indices in the HT group at 6 and 12 months, whereas the QT group demonstrated superior hamstring strength symmetry at 6, 12, and 24 months following ACL reconstruction (P < 0.05). Sinding et al.^[30] reported moderate reductions in both knee extensor and flexor strength following HT autograft reconstruction, while QT autografts resulted in more pronounced impairment of knee extensor strength alone. Meta-analysis was not performed due to heterogeneity in outcome reporting and assessment methods.

Secondary outcomes: Complications

Reported complications are summarized in Table 5.^[27-29,32]Harvest-site infection rates were documented in only one study, with no significant difference observed between graft groups.^[28] Overall, donor-site morbidity rates were not explicitly reported in any study; however, two trials provided mean donor-site morbidity scores.^[27,29] Meta-analysis demonstrated significantly lower donor-site morbidity scores in the QT group at 24 months (MD −4.67, 95% CI −9.29 to −0.05, P = 0.05) [Figure 6], with low heterogeneity (I² = 34%) and moderate certainty of evidence [Table 2].

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Figure 6:

Forest plot for post-operative donor site morbidity scores at final follow-up. IV: Inverse variance, QT: Quadriceps tendon, HT: Hamstring tendon, SD: Standard deviation, CI: Confidence interval.

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Four studies reported graft failure rates at 24 months.^[27-29,32]Pooled analysis showed no difference between QT and HT autografts, with six failures reported in each group (OR 1.06, 95% CI 0.32–3.53, P = 0.92, I² = 0%) [Figure 7].

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Figure 7:

Forest plot for post-operative graft failure rate at final follow-up. QT: Quadriceps tendon, HT: Hamstring tendon, SD: Standard deviation, CI: Confidence interval.

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Overall, adverse events were reported in four studies and were suitable for meta-analysis.^[27-29,32] No significant difference was identified between groups (OR 1.08, 95% CI 0.51–2.28, P = 0.83, I² = 0%) [Figure 8], with moderate certainty of evidence. None of the included studies reported quadriceps or hamstring muscle atrophy.^[27-32]

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Figure 8:

Forest plot for overall adverse event rate at final follow-up. QT: Quadriceps tendon, HT: Hamstring tendon, SD: Standard deviation, CI: Confidence interval.

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Secondary outcomes: Return to work and sport

Only one study assessed return-to-work and return-to-sport timelines.^[28] Mean time to return to work was 45.8 ± 42.7 days in the QT group and 75.2 ± 41.9 days in the HT group (P = 0.16). Mean time to return to sport was 95.2 ± 45.5 days for QT autografts and 82.1 ± 45.6 days for HT autografts (P = 0.62). No statistically significant differences were observed.

Human ethics and consent to participate: Not applicable

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. The PRISMA 2020 checklist was followed to ensure transparent and comprehensive reporting of the study.