The anterior cruciate ligament (ACL) is the principal restraint to anterior translation of the tibia on the femur and an important secondary restraint to rotational and valgus stresses at the knee. Its rupture is one of the most frequent serious ligament injuries in young, physically active individuals and typically follows a non-contact pivoting, decelerating or landing manoeuvre [1,2]. Population-based data from New Zealand estimated the incidence of ACL injury at approximately 37 per 100,000 person-years [3], and the number of reconstructions performed each year has risen steadily in registries and administrative databases from the United States and Australia [4–6]. The natural history of the ACL-deficient knee in active patients is unfavourable. Recurrent giving-way episodes limit sporting and occupational activity and expose the menisci and articular cartilage to repeated injury, which predisposes to early degenerative change [7–9]. A randomised trial has shown that structured rehabilitation with the option of delayed reconstruction can be a reasonable strategy in selected patients [10], but patients who remain symptomatic, who participate in pivoting sports, or who have associated reparable meniscal injury are generally advised to undergo reconstruction. Arthroscopic reconstruction using an autograft is now the accepted standard, and the choice of graft, tunnel placement, fixation and rehabilitation have all been refined over the past three decades [11–13]. The In dian context adds several considerations. Participation in organised and recreational sport, particularly cricket, football, kabaddi and athletics, is increasing, but a substantial proportion of ACL injuries in India also follow road traffic accidents, in which two-wheeler riders form the largest group of victims [14]. Patients often present late, sometimes after unsupervised treatment elsewhere, by which time secondary meniscal damage may already be present. In addition, many every day and cultural activities in the Indian subcontinent – squatting, sitting cross-legged, kneeling for prayer and using floor-level toilets – demand a far greater range of knee flexion than is required in Western populations [15]. A successful reconstruction in an Indian patient must therefore be judged not only by restored stability but also by the ability to perform such activities. Indian investigators have also emphasised that the ACL-deficient knee suffers a proprioceptive deficit, and that restoring neuromuscular control is an important goal of reconstruction and rehabilitation [16]. Clinical outcome after ACL surgery can be assessed with objective measures, such as instrumented laxity and clinical stability tests, and with patient-reported outcome measures (PROMs). Objective laxity correlates only modestly with how patients actually function, which is why PROMs are now considered essential. The Lysholm knee score, introduced in 1982 [17] and later modified by Tegner and Lysholm [18], is an eight-item questionnaire that yields a score from 0 to 100 and addresses limping, need for support, locking, instability, pain, swelling, stair climbing and squatting. Its reliability, validity and responsiveness in ACL-injured patients have been confirmed over 25 years of use [19,20], and it is used alongside the International Knee Documentation Committee (IKDC) subjective form [21]. Like every PROM it has limitations, including a potential ceiling effect in high-functioning patients and a mixture of symptom and function items [22]. Although the international studies on outcomes after ACL reconstruction is extensive, prospective Indian data that follow patients serially with a single, well-validated PROM and relate the results to patient- and injury-related factors are comparatively limited. The present study was undertaken to fill this gap. 1.1 Aim and objectives Aim: To compare the functional outcome before and after arthroscopic ACL reconstruction using the Lysholm knee score. Primary objective: To compare the pre-operative Lysholm score with the post-operative scores at 3, 6 and 12 months. Secondary objectives: (i) to analyse the change in each Lysholm domain; (ii) to categorise the outcome as excellent, good, fair or poor; (iii) to determine the association of age, sex, associated meniscal injury, time from injury to surgery and graft type with the final score; and (iv) to document clinical stability, complications and return to pre-injury activity.

2.1 Study design and setting This was a prospective, single-centre, observational study conducted in the Department of Orthopaedics of a tertiary-care teaching hospital in India. The study was approved by the Institutional Ethics Committee, and written informed consent was obtained from every participant before enrolment. Patients were consecutively recruited over a period of 24 months and each patient was followed for 12 months after surgery. 2.2 Sample size The sample size was calculated for a paired comparison of means using the formula n = (Zα + Zβ)² × σ² / d². Assuming a standard deviation of the change in Lysholm score (σ) of 10 points, a minimum detectable difference (d) of 4 points, a two-sided significance level of 5% and a power of 80%, the required sample was 49 patients. Allowing for approximately 20% loss to follow-up, 60 patients were enrolled. 2.3 Selection criteria Inclusion criteria: • Age 18–45 years of either sex; • Clinically (positive Lachman, anterior drawer and pivot-shift tests) and MRI-confirmed rupture of the ACL, isolated or associated with a meniscal tear; • Symptomatic instability or a desire to return to pivoting or demanding activity; • Willingness to give informed consent and to comply with the rehabilitation and follow-up schedule. Exclusion criteria: • Multiligament knee injury or posterior cruciate ligament injury requiring surgery; • Previous ACL surgery (revision) or previous surgery on either knee; • Associated fracture around the knee or Kellgren–Lawrence grade 3 or 4 osteoarthritis; • Inflammatory arthropathy, neuromuscular disorder or active infection; • Injury to the contralateral knee that could confound the functional score. 2.4 Pre-operative evaluation A detailed history (mode of injury, interval from injury, instability symptoms, previous treatment) and clinical examination (effusion, range of motion, Lachman, anterior drawer and pivot-shift tests, McMurray test, joint-line tenderness) were recorded. Plain radiographs and a magnetic resonance imaging (MRI) scan of the affected knee were obtained in all patients. All patients underwent a supervised pre-habilitation programme aimed at reducing effusion, restoring full extension and regaining quadriceps control before surgery. The baseline Lysholm score was recorded by an independent investigator, who administered the questionnaire in the language best understood by the patient. 2.5 Surgical technique All procedures were performed by the same team of arthroscopic surgeons under spinal or epidural anaesthesia with a thigh tourniquet. Standard anterolateral (viewing) and anteromedial (working) portals were used, and a systematic diagnostic arthroscopy was carried out. Associated meniscal tears were repaired when they were in the vascular zone and suitable for repair, and were otherwise treated by limited partial meniscectomy. The semitendinosus and gracilis tendons were harvested through a small anteromedial tibial incision and prepared as a quadrupled graft; in a minority of patients a central-third bone–patellar tendon–bone (BPTB) graft was used at the surgeon’s discretion. The femoral tunnel was drilled through the anteromedial portal and the tibial tunnel with an ACL tibial guide placed at the centre of the native footprint. Hamstring grafts were fixed on the femoral side with a suspensory cortical button and on the tibial side with a bio-absorbable interference screw, and BPTB grafts with interference screws at both ends [13]. The graft was tensioned with the knee in about 20° of flexion, and full extension was confirmed before closure. 2.6 Post-operative rehabilitation A uniform accelerated rehabilitation protocol was followed [23,24]. Quadriceps isometrics, ankle pumps, patellar mobilisation and active-assisted range-of-motion exercises were begun on the first post-operative day, with protected weight-bearing with a hinged brace for two weeks and progression to full weight-bearing by four weeks. Closed-chain strengthening, stationary cycling and balance and proprioceptive training were added from the second to the sixth week. Jogging in a straight line was permitted at about 12 weeks and sport-specific drills at 4–5 months. Return to pivoting sport was allowed at 9–12 months, subject to adequate strength, hop performance and a satisfactory clinical examination. 2.7 Outcome assessment The primary outcome was the Lysholm knee score (Table 1), recorded pre-operatively and at 3, 6 and 12 months by the same independent investigator. The total score (maximum 100) was graded as excellent (95–100), good (84–94), fair (65–83) or poor (≤64). Secondary outcomes were the Lachman test (grade 0–3) and pivot-shift test (negative, glide, clunk, gross), complications, and return to pre-injury activity (same level, lower level, or none) at 12 months. Table 1. Components and scoring of the Lysholm knee score Domain Max Response options (points) Limp 5 None (5); slight or periodic (3); severe and constant (0) Support 5 None (5); stick or crutch (2); weight-bearing impossible (0) Locking 15 No locking or catching (15); catching sensation without locking (10); locking occasionally (6); frequently (2); locked joint on examination (0) Instability 25 Never giving way (25); rarely, during athletic or severe exertion (20); frequently during athletic or severe exertion (15); occasionally in daily activities (10); often in daily activities (5); every step (0) Pain 25 None (25); inconstant and slight during severe exertion (20); marked during severe exertion (15); marked on or after walking >2 km (10); marked on or after walking <2 km (5); constant and severe (0) Swelling 10 None (10); with giving way (7); on severe exertion (5); on ordinary exertion (2); constant (0) Stair climbing 10 No problem (10); slightly impaired (6); one step at a time (2); unable (0) Squatting 5 No problem (5); slightly impaired (4); not beyond 90° (2); unable (0) Total 100 Excellent 95–100; good 84–94; fair 65–83; poor ≤64 Adapted from Lysholm and Gillquist, and Tegner and Lysholm. 2.8 Statistical analysis Data were entered in Microsoft Excel and analysed with SPSS software (version 25.0). Continuous variables are presented as mean ± standard deviation (SD) and categorical variables as number (percentage). Normality was checked with the Shapiro–Wilk test. Pre-operative and post-operative total scores were compared with the paired Student’s t-test, with Bonferroni correction for the multiple pairwise comparisons across time points (adjusted significance level 0.0167); the domain scores, being ordinal, were compared with the Wilcoxon signed-rank test. Subgroup comparisons of the 12-month score used the independent-samples t-test, and proportions were compared with the chi-square or Fisher’s exact test. A two-sided p value below 0.05 was considered statistically significant.

3.1 Patient characteristics Sixty patients were enrolled, and all completed the 12-month follow-up; none was lost to follow-up. The baseline demographic and clinical characteristics are summarised in Table 2. The mean age was 28.6 ± 6.4 years, and the majority of patients (86.7%) were males, with the highest proportion in the 26–35 year age group. The right knee was involved in 56.7% of patients. The mean interval from injury to surgery was 7.8 ± 4.9 months, and 45.0% of patients were operated on more than six months after injury. Table 2. Baseline demographic and clinical characteristics (n = 60) Characteristic Value Percentage (%) Age Mean ± SD (range), years 28.6 ± 6.4 (18–45) – 18–25 years 22 36.7 26–35 years 28 46.7 36–45 years 10 16.7 Sex Male 52 86.7 Female 8 13.3 Side involved Right knee 34 56.7 Left knee 26 43.3 Other Body mass index, kg/m² (mean ± SD) 24.3 ± 2.8 – Injury-to-surgery interval, months (mean ± SD) 7.8 ± 4.9 – Surgery within 6 months of injury 33 55.0 Surgery after more than 6 months 27 45.0 SD, standard deviation. Sports-related injury was the commonest mode of injury (48.3%), followed by road traffic accidents (30.0%). Associated meniscal injury was present in 25 patients (41.7%), the medial meniscus being most often involved. A quadrupled hamstring autograft was used in 52 patients (86.7%) and a BPTB graft in eight (13.3%); the mean hamstring graft diameter was 8.1 ± 0.6 mm (Table 3). Table 3. Mode of injury, associated meniscal injury and operative details (n = 60) Variable n Percentage (%) Mode of injury Sports injury 29 48.3 Road traffic accident 18 30.0 Fall / twisting injury during daily activity 9 15.0 Others 4 6.7 Associated meniscal injury None 35 58.3 Medial meniscus only 14 23.3 Lateral meniscus only 7 11.7 Both menisci 4 6.7 Meniscal management (n = 25) Meniscal repair 9 36.0 Partial meniscectomy 16 64.0 Graft used Quadrupled hamstring (semitendinosus + gracilis) autograft 52 86.7 Bone–patellar tendon–bone autograft 8 13.3 Percentages for meniscal management are calculated out of the 25 patients with meniscal injury. 3.2 Lysholm knee score over time The mean total Lysholm score rose from 52.4 ± 8.9 before surgery to 71.6 ± 7.8 at 3 months, 84.0 ± 6.9 at 6 months and 90.8 ± 5.7 at 12 months (Figure 1). Each of the increments was statistically significant (Table 4). The mean improvement from baseline to 12 months was 38.4 points (95% CI 35.9 to 40.9). Most of the gain occurred in the first six months; between 6 and 12 months the score continued to improve, but at a slower rate (mean gain 6.8 points), which suggests a plateau towards the end of the first year. Table 4. Comparison of Lysholm knee scores at different time points (paired t-test) Comparison Mean change SD of change 95% CI of change t value p value Pre-operative (52.4 ± 8.9) vs 3 months (71.6 ± 7.8) 19.2 8.4 17.0 to 21.4 17.71 <0.001 Pre-operative vs 6 months (84.0 ± 6.9) 31.6 9.1 29.2 to 34.0 26.90 <0.001 Pre-operative vs 12 months (90.8 ± 5.7) 38.4 9.7 35.9 to 40.9 30.66 <0.001 3 months vs 6 months 12.4 6.8 10.6 to 14.2 14.12 <0.001 6 months vs 12 months 6.8 5.2 5.5 to 8.1 10.13 <0.001 SD, standard deviation; CI, confidence interval. All p values remain significant after Bonferroni correction (threshold 0.0167). Figure 1. Mean Lysholm knee score (± SD) before and after ACL reconstruction. Shaded bands indicate the outcome categories. 3.3 Outcome categories Before surgery, none of the patients had an excellent or good result; 86.7% were in the poor category. At 12 months, 24 patients (40.0%) had an excellent and 29 (48.3%) had a good result, so 88.3% of patients achieved a good or excellent outcome, while only one patient (1.7%) remained in the poor category (Table 5, Figure 2). Table 5. Distribution of patients by Lysholm outcome category, n (%) Category (score) Pre-operative 3 months 6 months 12 months Excellent (95–100) 0 (0.0) 0 (0.0) 5 (8.3) 24 (40.0) Good (84–94) 0 (0.0) 3 (5.0) 31 (51.7) 29 (48.3) Fair (65–83) 8 (13.3) 41 (68.3) 22 (36.7) 6 (10.0) Poor (≤64) 52 (86.7) 16 (26.7) 2 (3.3) 1 (1.7) Total 60 (100) 60 (100) 60 (100) 60 (100) Distribution at 12 months differed significantly from the pre-operative distribution (Wilcoxon signed-rank test, p < 0.001). Figure 2. Distribution of Lysholm outcome categories at each assessment (numbers indicate patients). 3.4 Domain-wise analysis All eight domains improved significantly (p < 0.001 for each; Table 6). In absolute terms, the greatest gains were in instability (13.6 points) and pain (8.9 points), which together account for more than half of the total improvement. In relative terms, instability rose from a third of its maximum to 88% of its maximum (Figure 3). The squatting domain showed the smallest absolute gain and remained the weakest domain at 12 months (3.9 out of 5), indicating that a degree of residual difficulty with deep flexion persisted in some patients. Table 6. Domain-wise Lysholm scores before surgery and at 12 months (mean ± SD) Domain Max Pre-operative 12 months Mean change p value Limp 5 2.4 ± 1.1 4.7 ± 0.6 2.3 <0.001 Support 5 2.8 ± 1.2 4.7 ± 0.7 1.9 <0.001 Locking 15 10.6 ± 3.9 14.1 ± 2.1 3.5 <0.001 Instability 25 8.4 ± 4.6 22.0 ± 3.8 13.6 <0.001 Pain 25 14.2 ± 4.9 23.1 ± 3.2 8.9 <0.001 Swelling 10 6.0 ± 3.1 9.3 ± 1.6 3.3 <0.001 Stair climbing 10 5.6 ± 2.3 9.0 ± 1.4 3.4 <0.001 Squatting 5 2.4 ± 1.3 3.9 ± 1.2 1.5 <0.001 Total score 100 52.4 ± 8.9 90.8 ± 5.7 38.4 <0.001 Wilcoxon signed-rank test for domains; paired t-test for the total score. Figure 3. Domain-wise Lysholm scores expressed as a percentage of the domain maximum, before surgery and at 12 months. 3.5 Clinical stability Before surgery all patients had a positive Lachman test (60.0% grade 2 and 40.0% grade 3) and a positive pivot-shift test. At 12 months the Lachman test was grade 0 in 49 patients (81.7%) and grade 1 in 10 (16.7%), with only one patient (1.7%) showing grade 2 laxity. The pivot-shift test was negative in 51 patients (85.0%), a glide was present in 8 (13.3%) and a clunk in one (1.7%); no patient had a gross pivot shift (Table 7). Table 7. Clinical stability before surgery and at 12 months, n (%) Test and grade Pre-operative 12 months Lachman test Grade 0 (normal) 0 (0.0) 49 (81.7) Grade 1 (1–5 mm) 0 (0.0) 10 (16.7) Grade 2 (6–10 mm) 36 (60.0) 1 (1.7) Grade 3 (>10 mm) 24 (40.0) 0 (0.0) Pivot-shift test Negative 0 (0.0) 51 (85.0) Grade 1 (glide) 24 (40.0) 8 (13.3) Grade 2 (clunk) 30 (50.0) 1 (1.7) Grade 3 (gross) 6 (10.0) 0 (0.0) Differences between pre-operative and 12-month grades were significant for both tests (Wilcoxon signed-rank test, p < 0.001). 3.6 Factors influencing the final outcome The association between patient- and injury-related variables and the 12-month Lysholm score is shown in Table 8. Patients without associated meniscal injury had a significantly higher mean score than those with meniscal injury (92.3 ± 4.9 vs 88.7 ± 6.2; p = 0.019). Patients who were operated on within six months of injury tended to score higher than those operated on later (92.1 vs 89.2), but the difference narrowly missed statistical significance (p = 0.053). Age group, sex and graft type were not significantly associated with the final score, although the small number of female patients and of BPTB grafts limits the power of these comparisons. Table 8. Association of selected factors with the 12-month Lysholm score Factor N Lysholm score (mean ± SD) Test statistic (t) p value Age ≤30 years 39 91.6 ± 5.3 1.44 0.16 >30 years 21 89.3 ± 6.2 Sex Male 52 91.0 ± 5.6 0.62 0.54 Female 8 89.4 ± 6.9 Associated meniscal injury Absent 35 92.3 ± 4.9 2.41 0.019* Present 25 88.7 ± 6.2 Injury-to-surgery interval ≤6 months 33 92.1 ± 5.0 1.98 0.053 >6 months 27 89.2 ± 6.1 Graft type Hamstring autograft 52 90.7 ± 5.8 0.33 0.74 BPTB autograft 8 91.4 ± 4.9 *Statistically significant (p < 0.05). Independent-samples t-test. BPTB, bone–patellar tendon–bone. 3.7 Complications and return to activity There was no graft failure, deep infection, deep vein thrombosis or need for re-operation during the follow-up period. Minor complications were noted in a small number of patients, the commonest being numbness over the anteromedial leg (infrapatellar saphenous nerve branch) in four patients (6.7%) and a flexion deficit of more than 10° in three patients (5.0%), which improved with physiotherapy. Of the 60 patients, 40 (66.7%) returned to their pre-injury level of activity, 15 (25.0%) returned at a lower level and five (8.3%) did not return (Table 9). The reasons given for not returning to the previous level were fear of re-injury, change of occupation and residual discomfort during deep flexion or squatting. Table 9. Complications and return to pre-injury activity at 12 months (n = 60) Variable n Percentage (%) Complications Numbness over anteromedial leg (saphenous nerve branch) 4 6.7 Flexion deficit >10° (resolved or improving with physiotherapy) 3 5.0 Anterior knee pain 3 5.0 Superficial wound infection (resolved with antibiotics) 2 3.3 Loss of terminal extension ≥5° 2 3.3 Graft failure / re-rupture, deep infection, deep vein thrombosis 0 0.0 Return to pre-injury activity Same level 40 66.7 Lower level 15 25.0 Did not return 5 8.3 Some patients had more than one complication; categories are therefore not mutually exclusive.

The principal finding of this study is that arthroscopic ACL reconstruction produced a large and clinically important improvement in patient-reported knee function. The mean Lysholm score rose by 38.4 points, from a pre-operative value in the poor category to a mean in the good-to-excellent range at one year, and 88.3% of patients had a good or excellent result. This improvement is far larger than the change that has been considered clinically meaningful for this score [19,25], and the direction and magnitude are consistent with the meta-analytic evidence that functional scores improve substantially after reconstruction [26,27]. The time course of recovery deserves comment. About 82% of the total improvement was already present at six months, and the further gain between six and twelve months was modest. A similar pattern has been described after accelerated rehabilitation, in which early restoration of motion and quadriceps strength drives the rapid initial gains [23,24]. The relatively slower late gain probably reflects graft maturation and the gradual return of neuromuscular control, proprioception and confidence, factors that Indian authors have also stressed as being central to the success of reconstruction [16]. The 12-month assessment point used here is appropriate for functional scores, but ligamentisation of the graft and return to unrestricted sport continue beyond this time, and clinicians should counsel patients accordingly [28,29]. The domain-wise analysis shows where patients gain most. The instability and pain domains, which carry half of the weighting of the scale, improved the most, which is what would be expected from restoration of mechanical and rotational stability. This is supported by the stability tests, in which more than 80% of knees had a normal or near-normal Lachman test and 85% had a negative pivot shift. In contrast, squatting showed the smallest gain and remained the weakest domain. This finding is particularly relevant in the Indian setting, where squatting and cross-legged sitting are part of everyday life and call for knee flexion beyond 120°, often approaching 140° or more. Patients who cannot squat comfortably may regard a stable knee as an incomplete success, even when the total score is excellent. Possible contributors include harvest-related hamstring weakness, residual flexion deficit, anterior knee pain and fear of deep flexion on the reconstructed knee. Rehabilitation programmes designed for Indian patients should therefore deliberately include progressive deep-flexion training and proprioceptive work, rather than stopping at the flexion range of 120° that is usually regarded as satisfactory in Western protocols. Associated meniscal injury was the only factor significantly related to the final score in our series. Patients with meniscal injury scored on average 3.6 points lower than those with intact menisci. This agrees with the studies, in which meniscal and chondral damage at the time of surgery has been associated with poorer subjective and radiographic results at medium-term follow-up [30,31]. Meniscal damage is partly a consequence of delay: in a registry of more than 4,000 patients, the risk of meniscal and cartilage lesions increased as the interval between injury and surgery lengthened [32]. In our series, patients operated on within six months had a higher mean score than those operated on later, a difference that approached but did not reach significance (p = 0.053), and the mean interval from injury to surgery of nearly eight months is long by international standards. Late presentation is common in India for a variety of reasons, including delayed referral, limited access to arthroscopic facilities, cost, and initial treatment by non-specialists, and it is likely that earlier referral would reduce the burden of associated meniscal injury. In addition, injuries following road traffic accidents, which accounted for nearly one-third of our patients, are common in India and are often associated with other injuries that delay definitive ACL surgery. Age, sex and graft type did not significantly influence the 12-month score. Several registry studies have reported that females tend to report lower subjective scores than males after reconstruction [33], and females are also known to be at higher risk of primary injury because of differences in neuromuscular control and landing biomechanics [34]; however, our series contained only eight women, which is a reflection of the lower participation of Indian women in organised pivoting sports and of the limited power of this subgroup analysis. The lack of difference between hamstring and BPTB grafts is in line with the meta-analyses and long-term randomised trials, which have found broadly similar functional scores with the two grafts, with BPTB grafts offering slightly better stability at the cost of more anterior knee pain and kneeling discomfort [35]. This latter point is important for Indian patients who kneel frequently, and was one reason why hamstring grafts were preferred in most of our patients. Again, with only eight BPTB reconstructions, no firm conclusion regarding graft choice can be drawn from our data. Return to pre-injury activity is an important outcome that is not captured entirely by the Lysholm score. In our series, 66.7% of patients returned to their previous level of activity, which is higher than the pooled rate of about 55% for return to competitive sport reported in a systematic review [36], but lower than the rate of about 80% for return to some form of sport reported in an earlier review [37]. These differences emphasise that return to sport depends on psychological readiness, fear of re-injury, occupational and social circumstances as well as on the knee itself [38]. Our patients included many recreational athletes and manual workers, in whom return to a previous “level” is not easily defined, and these figures should be interpreted cautiously. The complication rate in our series was low and the complications minor, and no patient suffered graft failure within the first year. However, one-year follow-up is too short to judge the long-term consequences of ACL injury and reconstruction. Even after technically successful surgery, a considerable proportion of patients develop radiographic osteoarthritis [39], and the risk of a second ACL injury, in either knee, is not negligible, especially in younger patients and those returning to pivoting sports [40]. Registry-based follow-up, which has been established in several Scandinavian countries [41], would allow these issues to be addressed in the Indian context, and our results support the need for a national or multicentre registry of ACL reconstruction in India. 4.1 Strengths and limitations The strengths of this study are its prospective design, the use of a single validated PROM with serial follow-up, the standardised surgical technique and rehabilitation protocol, and complete follow-up. Its limitations include the single-centre design, the modest sample size, the absence of a control group, and the fact that only a single PROM (without a complementary measure such as the IKDC subjective score or Tegner activity scale) was used. The Lysholm scale may overestimate function in patients with high demands because of its ceiling effect. The numbers of female patients and BPTB reconstructions were too small for meaningful subgroup analysis, the follow-up of 12 months is short for the assessment of osteoarthritis and re-injury, and the Lysholm questionnaire was administered in the vernacular without a formally validated Indian-language version. Larger multicentre studies with longer follow-up and objective measures of strength, hop performance and deep-flexion capacity are recommended.

Arthroscopic ACL reconstruction followed by a structured accelerated rehabilitation programme resulted in a large, statistically significant and clinically meaningful improvement in the Lysholm knee score, from a mean of 52.4 before surgery to 90.8 at 12 months, with 88.3% of patients achieving a good or excellent result. Most of the improvement occurred within the first six months, and the greatest gains were in instability and pain. Concomitant meniscal injury was associated with a lower final score, and there was a trend for better outcomes with earlier surgery, which underlines the need for early diagnosis and timely referral. Residual difficulty with squatting should be specifically addressed in rehabilitation protocols designed for Indian patients. The Lysholm score is a simple and useful tool for the serial assessment of outcome after ACL reconstruction in routine practice. ACKNOWLEDGEMENTS The authors thank the staff of the Department of Orthopaedics, the operating-room team and the physiotherapists for their assistance with patient care and follow-up. CONFLICT OF INTEREST AND FUNDING The authors declare no conflict of interest. No external funding was received for this study.

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