A Study of Functional Outcome of Arthroscopic Anterior Cruciate Ligament Reconstruction Using Hamstring Graft

Objectives

1. To assess post-operative knee stability using clinical tests, including the Lachman and pivot-shift tests, at predetermined follow-up intervals

2. To evaluate changes in knee range of motion during the post-operative follow-up period

3. To assess functional recovery following arthroscopic ACL reconstruction using the Lysholm Knee Scoring Scale

4. To assess post-operative complications following arthroscopic ACL reconstruction using a hamstring tendon autograft.

Study design and setting

A prospective observational study was conducted in the Department of Orthopaedics, M.G.M. Medical College and L.S.K. Hospital, Kishanganj, Bihar, over a period of 18 months. The study included patients aged 18–50 years with clinically and radiologically confirmed ACL tears who underwent arthroscopic ACL reconstruction using a hamstring tendon autograft. This was a single-arm study without randomization or a comparison group receiving BPTB reconstruction, allograft reconstruction, or non-operative management.

Study population and sample size

The study population comprised patients presenting with ACL injuries who were planned for primary arthroscopic ACL reconstruction using a hamstring autograft. A total of 50 patients were included in the study.

The sample size was calculated using the single-proportion formula:

n = Z²p (1−p)/E²

where Z = 1.28 for an 80% confidence level, P = 0.50 (expected proportion), and E = 0.091 (allowable margin of error). Accordingly:

n = (1.282 × 0.50 × 0.50)/(0.0912) = 49.46

The calculated sample size was rounded up to 50 participants. This single-proportion calculation did not establish statistical power for detecting changes in Lysholm scores, uncommon complications, or differences between patient subgroups. The small sample therefore limits statistical precision and generalizability.

Eligibility criteria

Patients aged 18–50 years with a clinically and radiologically confirmed ACL tear, who were willing to participate and comply with the scheduled follow-up assessments, were eligible for inclusion. Patients were also required to have no pre-existing pathology involving the contralateral knee.

Patients undergoing revision ACL reconstruction were excluded. Patients with ACL injuries associated with intra-articular fractures, previous surgery on the affected knee, or complex ligamentous injuries requiring surgical intervention, including posterior cruciate ligament injuries, collateral ligament injuries requiring reconstruction, or posterolateral corner injuries, were excluded. Patients with established osteoarthritis of the affected knee were also excluded.

Pre-operative assessment

All patients underwent a detailed clinical evaluation followed by radiological assessment and magnetic resonance imaging to confirm the ACL tear and identify associated intra-articular pathology. Pre-operative knee stability was assessed using the anterior drawer test, posterior drawer test, Lachman test, and pivot-shift test. Relevant demographic and clinical information was recorded using a standardized study pro forma.

Surgical technique

All procedures were performed using a standardized arthroscopic ACL reconstruction technique with a hamstring tendon autograft. Following routine pre-operative preparation, patients received combined spinal and epidural anesthesia and were positioned supine with the operative knee appropriately supported. A pneumatic tourniquet was applied to the proximal thigh, and the operative limb was prepared and draped under aseptic precautions.

Diagnostic arthroscopy was initially performed through standard anterolateral and anteromedial portals to confirm the ACL tear and assess associated intra-articular pathology, particularly meniscal injuries. Associated meniscal pathology identified during arthroscopy was treated according to the nature of the lesion. The torn ACL tissue was debrided as required, and the native femoral and tibial ACL footprints were identified. The reported data did not specify the numbers undergoing meniscal repair, partial meniscectomy, or other meniscal management, and functional outcomes were not stratified by meniscal treatment.

Hamstring graft harvesting and preparation

The semitendinosus and gracilis tendons were harvested through a longitudinal incision over the pes anserinus while taking care to protect the saphenous nerve and surrounding soft tissues. The tendons were carefully released from their attachments and harvested using a tendon stripper. The harvested tendons were kept moist in normal saline, and residual muscle tissue was removed.

The tendons were subsequently prepared and quadrupled over a graft preparation device. The graft was trimmed to an appropriate length and diameter and secured using whip-stitch sutures. The final graft dimensions were recorded before implantation. Although graft dimensions were recorded, graft diameter was not included in the reported outcome analysis.

Femoral and tibial tunnel preparation

The native ACL footprints were identified arthroscopically, and the femoral and tibial tunnels were created using standard anatomical tunnel-placement techniques. When required, limited notchplasty was performed to prevent graft impingement. The femoral tunnel was prepared using a femoral guide, while the tibial tunnel was created using a tibial guide positioned to reproduce the anatomical orientation of the native ACL. The tunnels were appropriately sized according to the prepared graft.

Graft placement and fixation

The prepared hamstring graft was introduced arthroscopically through the tibial and femoral tunnels. Femoral fixation was achieved using a closed-loop cortical button. After appropriate positioning and cyclic tensioning of the graft through repeated knee flexion and extension, tibial fixation was performed using an interference screw. Excess graft tissue was trimmed. Final graft positioning and knee stability were assessed intraoperatively using the Lachman and pivot-shift tests (Fig. 1).

Post-operative management and rehabilitation

A standardized postoperative rehabilitation protocol was initiated from the 1st post-operative day. Wound dressings were changed on post-operative days 2 and 7, and sutures were removed on approximately post-operative day ^[10]. During the initial 4 weeks, the knee was supported with a long knee brace, and flexion was restricted according to the rehabilitation protocol. From the second post-operative month, progressive quadriceps and hamstring strengthening exercises were initiated following brace removal. Patient adherence to exercises and attendance at supervised physiotherapy were not quantified; a prescribed standardized protocol should therefore not be interpreted as confirmed uniform rehabilitation exposure.

Follow-up and outcome assessment

Patients were followed clinically at 1, 2, 3, 6, and 12 months after surgery. At each follow-up visit, clinical assessment of knee stability was performed using the anterior drawer, Lachman, posterior drawer, and pivot-shift tests, as appropriate. Functional outcome was assessed using the Lysholm Knee Scoring Scale. All findings were documented prospectively in a standardized pro forma. Instrumented laxity testing (such as KT-1000/KT-2000), IKDC, Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner activity scale, ACL-Return to Sport after Injury, and formal return-to-sport outcomes were not part of the study protocol. Return to the pre-injury sports level, time to return to sport, and post-operative sports participation were not evaluated. The reported clinical tests do not provide quantitative instrumented laxity estimates.

The primary assessment of functional recovery was based on the change in Lysholm knee score during postoperative follow-up. Clinical knee stability and post-operative complications were also documented. Associated meniscal pathology and the injury-to-surgery interval were recorded descriptively; the study was not designed or powered for adjusted subgroup analyses of their independent effects on functional outcome. Rehabilitation was standardized by protocol, but adherence and physiotherapy attendance were not quantitatively measured. No analysis of the relationship between surgical timing and Lysholm outcome, or between the type of meniscal treatment and post-operative function, was performed.

Complication frequencies were expressed using all 50 patients as the denominator; percentages in Fig. 2 used the 15 patients reported to have a complication. The available report did not provide operational definitions, diagnostic criteria, severity grades, or case-specific treatment and resolution for anterior knee pain, infection, tunnel widening, tibial screw dislodgement, graft failure, or stiffness. For tunnel widening, the imaging modality and views, measurement landmarks, baseline comparison, assessment timing, and threshold for a clinically relevant increase were not documented. These events were therefore retained as descriptive reported complications rather than standardized or independently verified endpoints.

Statistical analysis

Data were entered into a Microsoft Excel spreadsheet and analyzed using statistical software. Continuous variables were summarized using mean and standard deviation, while categorical variables were expressed as frequencies and percentages. Changes in functional outcome scores across follow-up were assessed using repeated-measures methods according to data distribution, with a two-sided P < 0.05 considered statistically significant. Because this was a small, single-arm observational study, analyses were primarily descriptive and within-cohort; no between-graft comparison or multivariable adjustment for age, sex, associated meniscal injury, injury-to-surgery interval, or activity level was performed. Effect-size estimates and confidence intervals were not available for all outcomes, and this is acknowledged as a limitation. No multivariable model assessed the independent contributions of age, sex, baseline activity, injury chronicity, meniscal pathology or treatment, graft diameter, and rehabilitation exposure. The exact repeated-measures test and P-value were not specified in the available report; the reported P < 0.05 was retained without reanalysis, and no additional inferential estimates were generated from aggregate data.

Ethical considerations

The study was conducted after obtaining approval from the Institutional Ethics Committee. Written informed consent was obtained from all participants before enrollment. Patient confidentiality was maintained throughout the study, and the study procedures were conducted in accordance with the ethical principles governing research involving human participants.

Baseline characteristics

The baseline characteristics of the patients showed that the mean age of the study participants was 31.72 ± 8.88 years, with the highest proportion belonging to the 26–30-year age group (20%), followed by the 31–35-year age group (18%). The study population was predominantly male (72%), with a male-to-female ratio of 18:7. Regarding occupation, 40% were engaged in office work/housework, followed by recreational sports (32%) and labor work (28%). The left knee was more commonly involved (56%) than the right knee (40%), while bilateral involvement was observed in 4% of patients. Road traffic accidents were the most common mode of injury (44%), followed by sports-related injuries (36%) and falls (20%) (Table 1).

Clinical, injury-related and intraoperative characteristics

The clinical, injury-related, and intraoperative characteristics showed that the majority of patients (52%) underwent surgery within 4–6 months of injury, followed by 32% who underwent surgery within 6 weeks–3 months. Giving way was the most common presenting symptom (100%), followed by pain (76%) and swelling (28%). Medial meniscus tear was the most frequently observed associated meniscal finding (40%), followed by lateral meniscus tear (32%), while 12% had an isolated ACL tear. The mean duration of surgery was 92.6 ± 15.4 min, with a mean intraoperative blood loss of 100.0 ± 40.0 mL (Table 2). These injury-to-surgery and meniscal categories are descriptive; their associations with functional outcome were not evaluated, and treatment-specific meniscal outcomes were unavailable.

Post-operative complications were recorded in 15 of 50 patients (30%). Using the entire study cohort (n = 50) as the denominator, anterior knee pain occurred in 5 patients (10%), tunnel widening in 4 (8%), infection in 3 (6%), and dislodgement of the tibial screw, graft failure, and knee stiffness in 1 patient each (2% each). Fig. 2 shows the relative distribution of these complications among the 15 affected patients. These counts are retained as reported. Event definitions, severity, management, and resolution were not available, limiting interpretation of the overall complication burden and comparisons with other cohorts.

Post-operative functional outcomes according to the Lysholm Knee Scoring Scale showed that 52.0% of patients had good outcomes and 32.0% had excellent outcomes. The mean Lysholm score improved significantly from 50.74 ± 6.342 preoperatively to 86.00 ± 10.067 postoperatively (P < 0.05) (Table 3).

Representative post-operative radiographs and clinical photographs demonstrating post-operative knee flexion and extension are shown in Figs. 3, 4, 5, and 6.

Limitations

This study included only 50 patients at a single institution, limiting statistical power, precision, detection of uncommon complications, and generalizability to other hospitals and patient populations. The sample-size calculation for a single proportion did not demonstrate power for longitudinal functional comparisons or subgroup analyses. The prospective observational design lacked randomization and a comparator receiving BPTB reconstruction, allograft reconstruction, or non-operative management. Selection bias and confounding therefore remain possible; the observed improvement cannot be attributed causally to hamstring autograft reconstruction or used to establish its superiority. The 12-month follow-up was insufficient to assess long-term graft survival, recurrent instability, osteoarthritis, or sustained sports participation.

Functional assessment relied principally on the Lysholm Knee Scoring Scale. IKDC, KOOS, and Tegner activity scores were not reported, limiting assessment across other domains of knee function and activity. Return to the pre-injury sports level, time to return to sport, and post-operative sports participation were not evaluated. Clinical Lachman and pivot-shift examinations were performed, but KT-1000/KT-2000 or other quantitative instrumented laxity measurements were not reported; objective stability could therefore not be characterized comprehensively.

Associated meniscal injuries were common, but the specific treatments and their separate effects on functional recovery were not analyzed. The injury-to-surgery interval varied from 6 weeks to more than 1 year, and its relationship with outcome was not evaluated. Rehabilitation adherence and physiotherapy attendance were not quantified. Consequently, variation in meniscal treatment, surgical timing, and rehabilitation exposure may have influenced recovery. Surgeon number, experience, and possible inter-surgeon variability were not captured in the reported dataset.

Although full-cohort denominators have been clarified, the report lacked standardized definitions, diagnostic criteria, severity grading, and management or resolution details for the recorded complications. Tunnel widening was reported without a documented imaging modality, measurement method, baseline comparison, timing, or clinically relevant threshold. Its frequency must therefore be interpreted as a descriptive observation, and its clinical significance remains uncertain. These reporting gaps also limit comparisons of complication rates with other studies.

No multivariable analysis adjusted for age, sex, activity level, injury chronicity, meniscal pathology or treatment, graft diameter, or post-operative rehabilitation. Their independent effects cannot be separated from the observed functional improvement. Confidence intervals and standardized effect sizes were not provided, and the exact statistical test and exact P-value underlying the reported significance were not specified. Larger multicenter comparative studies with longer follow-up, broader validated outcome measures, formal return-to-sport assessment, quantitative stability testing, documented rehabilitation adherence, standardized complication and imaging criteria, and prespecified adjusted analyses are needed.

Conflict of Interest:

Nil

Source of Support:

Nil

Consent

The authors confirm that informed consent was obtained from the patient for publication of this article

How to Cite this Article

Akhil M, Singh A, Gera Y. A Study of Functional Outcome of Arthroscopic Anterior Cruciate Ligament Reconstruction Using Hamstring Graft. J Orthop Case Rep. 2026 November;16(11):419-428. doi: 10.13107/jocr.2026.v16.i11.8514.