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Evaluating the efficacy of hamstring autografts for anterior cruciate ligament reconstruction in the Indian population
*Corresponding author: Alokik Gupta, Department of Orthopaedics, Thunga Hospital, Mumbai, Maharashtra, India. alokik.95@gmail.com
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Received: ,
Accepted: ,
How to cite this article: Gupta A, Shetty N. Evaluating the efficacy of hamstring autografts for anterior cruciate ligament reconstruction in the Indian population. J Arthrosc Surg Sports Med. doi: 10.25259/JASSM_25_2025
Abstract
Objectives:
Anterior cruciate ligament (ACL) reconstruction commonly utilizes hamstring tendon autografts due to favorable biomechanical properties and low donor-site morbidity. However, anatomical variability, especially in the Indian population, may impact graft adequacy in replicating the native ACL insertion footprint size. The purpose of the study is to evaluate whether quadrupled semitendinosus (ST) autografts sufficiently match the native ACL tibial and femoral footprint dimensions in the Indian population
Materials and Methods:
Fifty knees from Indian individuals aged 13–44 years were evaluated arthroscopically. ACL tibial and femoral footprints were measured intraoperatively. In 40 cases, ST and gracilis tendons were harvested, and graft diameters were recorded in both doubled and quadrupled configurations. Ten cases used alternative grafts (quadriceps tendon, n = 4; peroneus longus, n = 6) due to insufficient hamstring graft size. Statistical comparisons were made between graft dimensions and native footprint sizes
Results:
The mean tibial and femoral footprint widths were 11.9 ± 2.0 mm and 9.5 ± 1.2 mm, respectively. The mean quadrupled ST graft diameter was 7.95 ± 0.6 mm, significantly smaller than the footprint dimensions (P < 0.001). Graft insufficiency was more frequent in female and younger patients. Supplementary lateral extraarticular tenodesis was performed in 8 cases
Conclusion:
Hamstring autografts, particularly ST tendons alone, may be inadequate to replicate native ACL anatomy in the Indian population. Pre-operative assessment and individualized graft selection, including alternative options, are recommended to optimize surgical outcomes and restore joint stability
Keywords
Anatomical ACL reconstruction
Femoral footprint
Hamstring autograft
Quadrupled semitendinosus tendon
Tibial footprint
INTRODUCTION
The anterior cruciate ligament (ACL) is critical for maintaining knee joint stability and facilitating a normal range of motion. ACL injuries are prevalent among active individuals, particularly athletes, often necessitating surgical reconstruction to restore knee function and enable return to activity.[1,2]
Among various graft options, hamstring tendon autografts – typically involving the semitendinosus (ST) and gracilis (G) tendons – are widely used due to their biomechanical compatibility with the native ACL and relatively faster rehabilitation times.[3,4] Despite these advantages, the efficacy of hamstring autografts in the Indian population remains under scrutiny, primarily due to concerns about anatomical variation, particularly smaller graft sizes.[5,6]
Notably, in ACL reconstruction using autografts, the dimensions of the reconstructed ligament are largely dictated by the harvested graft size rather than the dimensions of the native ACL insertion site. When the harvested graft is smaller, the reconstructed ACL may not sufficiently replicate the native structure, potentially compromising surgical outcomes.[7,8] As anatomical restoration is a key goal of ACL reconstruction, a near-precise match between the graft size and the native insertion site is desirable.
This study aims to evaluate whether quadrupled ST tendons in the Indian population are of sufficient size to anatomically replicate the native ACL. The hypothesis is that quadrupled ST tendon autografts are significantly smaller than the native ACL insertion site in Indian knees.
MATERIALS AND METHODS
Study population
A total of 50 non-paired knees from Indian individuals aged 13–44 years were included in this study. The sample included 9 females and 41 males.
Footprint evaluation
During diagnostic arthroscopy, the tibial [Figure 1] and femoral [Figure 2] ACL footprints were measured using an arthroscopic ruler introduced through the transpatellar tendon portal and viewing through standard anteromedial or anterolateral portals. These measurements were used to guide the selection of graft type and size.[9]
- Tibial footprint.
- Femoral footprint.
Graft harvest and measurement
In 40 cases, hamstring autografts were harvested and utilized for reconstruction. The ST and G tendons were harvested from their tibial insertion points with a closed tendon stripper to their proximal ends, with all muscle tissue carefully removed.
The harvested ST tendon was measured both in its doubled [Figure 3] and quadrupled [Figure 4] states using a standardized graft sizer [Figures 5 and 6]. Similarly, the G tendon was doubled and measured.
- Doubled semitendinosus.
- Quadrupled semitendinosus.
- Width of doubled semitendinosus.
- Width of quadrupled semitendinosus.
In 10 cases where hamstring autografts were deemed unsuitable based on anatomical large footprints constraints, alternative grafts were used: quadriceps tendon (n = 4) and peroneus longus tendon (n = 6). Both of which have shown that they are reliable grafts in Indian population.[10,11]
RESULTS
Demographics: Among the 50 patients, 9 were female, and 41 were male. Ages ranged from 13 to 44 years.
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Graft utilization:
Hamstring autografts were used in 40 cases.
Quadriceps tendon grafts in 4 cases.
Peroneus longus tendon grafts in 6 cases.
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Footprint dimensions:
Tibial footprint: Range 8–16 mm; Mean: 11.9 mm.
Femoral footprint: Range 8–12 mm; Mean: 9.5 mm.
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Graft dimensions:
Doubled ST: Range 5.5–7 mm; Mean: 5.925 mm.
Quadrupled ST: Range 7–9 mm; Mean: 7.95 mm [Table 1].
Data summary
| Measurement type | Mean (mm) | SD (estimated) |
|---|---|---|
| Tibial footprint | 11.9 | 2.0 |
| Femoral footprint | 9.5 | 1.2 |
| Semitendinosus doubled (STx2) | 5.925 | 0.5 |
| Semitendinosus quadrupled (STx4) | 7.95 | 0.6 |
SD: Standard deviation
Out of the 50 cases evaluated, in 48 cases, the measured quadrupled ST tendons were found to be smaller than the native ACL insertion sites, particularly in younger and female patients.
Statistical analysis confirmed that quadrupled ST autografts were significantly smaller than the tibial and femoral ACL footprints (P < 0.001), reinforcing concerns about anatomical mismatch and the potential need for alternative graft strategies in the Indian population.
Our grafts (5-strand - tripled ST and doubled G, 6-strand - quadrupled ST and doubled G, quadriceps tendon, peroneus longus tendon) width ranged from 8 mm to 10 mm with a mean of 9.06 mm.
A quadrupled ST tendon was used as a graft in only 2 of the 50 cases, chosen due to the presence of small femoral footprints and the need for a smaller tunnel. These cases involved a 13-year-old boy with open physes and a 15-year-old boy with partially closed physes.
8 cases were supplemented with lateral extraarticular tenodesis. The Beighton score in 5 out of 8 cases was more than 6 out of 9, suggestive of joint hypermobility. The indications are high-grade pivot shift, high-level athletes (Ranji Trophy players, football players), and adolescent young females, as they are all at high risk of graft retear.
DISCUSSION
The present study assessed the adequacy of hamstring tendon autografts – specifically, quadrupled ST quadrupled – in replicating the native ACL insertion site dimensions in the Indian population. The results demonstrated a statistically significant disparity between the size of harvested grafts and the dimensions of the tibial and femoral ACL footprints (P < 0.001), validating our hypothesis that hamstring autografts are often insufficient in size to restore the native ACL anatomy in this demographic.
Comparison with existing literature
Multiple studies from Western populations have reported successful anatomical reconstructions using hamstring autografts.[3,4] However, these findings may not be entirely applicable to populations with smaller anthropometric profiles. Studies from Asia, including those by Adhikari et al[6] and Chung et al,[10] have highlighted that hamstring tendon diameters in Asian populations, including Indians, are generally smaller than their Western counterparts.[11] This anatomical variation is a critical consideration in achieving a graft size that sufficiently replicates the native ACL.
Our findings corroborate this, with the mean quadrupled ST graft measuring only 7.95 mm – significantly smaller than the average tibial footprint (11.9 mm) and femoral footprint (9.5 mm). These results are consistent with research by Magnussen et al [7] and Mariscalco et al,[8] who found that smaller graft diameters (<8 mm) are associated with higher revision rates and inferior clinical outcomes.
Anatomical ACL reconstruction aims to replicate not only the function but also the native insertion area of the ACL. The tibial and femoral footprints are not just landmarks – they determine the functional integration of the graft with surrounding structures and influence rotational stability.[9]
A graft that fails to sufficiently cover these footprints may result in:
Decreased resistance to anterior tibial translation
Impaired proprioception and joint stability
Increased risk of early graft elongation or failure.
Moreover, graft size has been directly correlated with load-to-failure strength and stiffness – key mechanical properties for long-term success. A smaller graft not only mismatches the anatomical footprint but may also be mechanically inferior.
Clinical implications
The results of this study have significant clinical relevance, particularly for orthopedic surgeons practicing in India or treating patients of similar anthropometric profiles. The observed discrepancy between the dimensions of hamstring autografts and the native ACL footprint raises concerns about the adequacy of anatomical restoration when relying solely on hamstring tendons in ACL reconstruction. Quadrupled ST graft, 4-strand ST, G graft is by far a most commonly preferred graft configuration. All inside graft link ACL with quadrupled ST is another very popular technique.
Risk of suboptimal reconstruction
When the graft diameter is smaller than the native insertion site, it may fail to restore the full biomechanical function of the ACL. This can lead to:
Residual joint laxity
Decreased rotational stability
Higher likelihood of graft failure or re-tear, especially in high-demand athletes
Accelerated cartilage wear and early osteoarthritis
Graft impingement and tunnel malposition, therefore, hamper the range of motion as well.
Studies by Magnussen et al.[7] and Mariscalco et al.,[8] have shown that smaller graft diameters (<8 mm) are associated with increased failure rates, particularly in younger and more active individuals.
Importance of preoperative assessment
This study emphasizes the value of:
Intraoperative footprint measurement to guide appropriate graft selection, ensuring the reconstructed ligament approximates the native ACL’s footprint and mechanical profile.
Tailored graft selection
Surgeons should be cautious about defaulting to hamstring autografts without confirming their suitability. When the hamstring tendon is insufficient:
Quadriceps tendon (partial or full thickness) can provide a robust and larger graft, especially in high body mass index (BMI), male patients, or athletes (Wrestlers).[12]
The peroneus longus tendon offers another viable alternative, particularly in cases where hamstrings or quadriceps are contraindicated or previously harvested.[13]
Bone Tendon Bone (BTB) graft is the gold standard for footballers.
This individualized approach reduces the risk of surgical failure and improves functional outcomes by prioritizing anatomical restoration over convenience or habit.
Gender and age-specific considerations
Female patients, especially those with high BMI and adolescents, tend to have smaller hamstring tendons. For these demographics, surgeons should:
Be more vigilant in intraoperative graft assessment
Consider using augmentation techniques (e.g., hybrid grafts) or opting for alternative graft sources
Monitor post-operative rehabilitation more closely due to the potential for graft insufficiency or delayed healing
Future surgical planning
The findings also have implications for:
Revision ACL reconstructions, where limited autograft options may be available.
Surgical education, young orthopedic surgeons should be trained to perform multiple graft harvests confidently.
Policy development, particularly for national ACL registries in India, to track long-term outcomes based on graft choice and patient anatomy.
Limitations
While this study provides valuable insights into the anatomical adequacy of hamstring autografts in the Indian population, several limitations must be acknowledged:
Sample size and population
The study included 50 non-paired knee evaluations, which, while informative, may not be sufficient to generalize findings across the diverse Indian population. Variability in regional anthropometry, gender distribution, and activity levels may influence tendon dimensions and footprint sizes.
Single-center design
All procedures and measurements were conducted at a single institution, possibly introducing bias related to technique, instrumentation, or surgeon-specific practices. A multicenter approach would offer a broader representation and increase external validity.
Lack of long-term clinical correlation
The study focused on anatomical measurements and statistical comparison but did not follow up on functional outcomes, graft failure rates, or return to sport/activity. Without clinical endpoints, the impact of graft-geometry mismatch on patient outcomes remains speculative.
Intraoperative measurement limitations
Although arthroscopic rulers were used to measure femoral and tibial footprints, intraoperative measurements may be subject to human error, tissue deformation, or arthroscopic visualization challenges. A combination of pre-operative MRI measurements and 3D modeling could provide more precise footprint analysis.
CONCLUSION
Quadrupled ST tendon autografts may not consistently replicate native ACL insertion dimensions in the Indian population, potentially compromising anatomical and functional restoration. Surgeons should consider individualized graft selection based on footprint measurements and patient-specific anatomical features to optimize surgical outcomes.
A minimum graft length of 60 mm is required to ensure adequate coverage of the femoral, tibial, and intra-articular segments. To achieve this, a minimum ST tendon length of 240 mm is necessary. This requirement was fulfilled in 38 cases. In 2 cases, the ST tendon measured less than 240 mm; consequently, a five-strand construct comprising a tripled ST and a doubled G tendon was utilized. Importantly, graft length does not influence the implementation of accelerated rehabilitation protocols in athletic populations.
Authors contributions:
AG: Concepts, design, definition of intellectual content, literature search, clinical studies, experimental studies, data acquisition, data analysis, statistical analysis, manuscript preparation, manuscript editing and review; NS: Concepts, data acquisition, clinical studies, experimental studies, manuscript editing and review.
Declarations
Ethical approval statement:
Ethical approval was not obtained prior to the commencement of this study as all procedures performed were part of routine standard-of-care ACL reconstruction. No additional intervention, randomization, or deviation from accepted surgical practice was involved. This was a retrospective analysis of the patient’s anonymised data.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
Availability of data and material:
The data was collected from the patients that were operated in the hospital. All the data of 50 patients was collected by me and the conclusion was withdrawn from that.
Financial support and sponsorship: Nil.
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