The anterior cruciate ligament (ACL) is an important ligamentous structure in the knee joint which helps in maintaining stability. ACL tears contribute to approximately 50% of knee injuries. ^[1] ACL reconstruction has been the standard surgical procedure in the case of ACL insufficiency. Over decades ACL reconstruction has evolved in terms of technique and graft used. 

The patients in whom the Hamstring tendon (HST) is used as an auto graft for ACL reconstruction have early recovery of quadriceps strength, good graft uptake, better tensile strength and less joint stiffness with satisfactory results in terms of patient compliance. ^[2] But it has limitations like random graft size, a probable decrease in knee joint flexion power, infection risk due to inadequate closure of the sartorius fascia and injury to the saphenous nerve during harvesting. ^[3]

               Peroneus longus tendon (PL) is being used as an alternative toHST graft in recent years. ^[4] Tensile strength of fourstrand hamstrings and double-strand peroneus longus was found to be higher than naive ACL which provides provision for the thought of harvesting peroneus longus for ACL reconstruction.6 Adequate diameter and length of PL have their upper hand over hamstrings autograft. It was found that even the anterior half of the PL tendon has enough length and strength to be effective in ACL reconstruction. ^[5] Harvesting the entire PL has no effect on the stability of the ankle or gait proven by a biomechanical and kinematic study. ^[6]

               In assessing the donor site morbidity, muscle strength has been believed to be a potential factor for physical performance, activities of daily living and sports activities. Hence following ACL reconstruction with HST or PL graft, the motor power of knee and ankle joint performance needs to be assessed.

               The purpose of this study is to compare the functional outcome of knee and ankle by using MCS, Lysholm score and AOFAS respectively and donor site morbidity by measuring flexion and extension strength at the knee and eversion and plantar flexion strength at the ankle by HHD after ACL reconstruction using hamstrings and peroneus longus autograft. The outcomes were evaluated in each group preoperatively and at 6 months and 1 year postoperatively and analysed.

This prospective cohort study was conducted was conducted int he Department of Anaesthesia and Critical Care and Orthopaedics, Tertiary Care Teaching Hospital.

With 194 patients with ages between 16 and 50 years of either gender who presented with an isolated symptomatic ACL rupture being included after proper written informed consent. Patients were excluded if they had other associated intraarticular pathology, stiffness of the joint, multiligamentous injury, or associated fractures around the knee joint. All included patients were randomly allocated into HT and PLT groups, operated on, and then rehabilitated. For both groups, patients were made to fill out the International Knee Documentation Committee (IKDC) score form, the Lysholm score form, and the ankle-hindfoot score form at the preoperative stage and during subsequent follow-up periods. The thigh circumference of the injured limb was measured 15 cm proximal to the superior pole of the patella and compared with the contralateral healthy side. Similarly, all the patients were also assessed for knee stability using clinical tests (the anterior drawer, Lachman, and pivot shift tests).

Patients were subjected to a detailed pre-operative clinical and radiological examination (radiographs and MRI) to establish the diagnosis and formulate the plan of treatment. They underwent diagnostic arthroscopy and a definitive procedure under the effect of spinal anesthesia

In our study, 60 patients of ACL injury were operated. There were 30 (50%) patients in Group H (Hamstring tendon graft) and 30 (50%) patients in Group P (Peroneus Longus tendon graft). The mean age of patients in Group-H was 35.15 ± 11.23 years (range 20-54 years) and in Group-P, it was 32.95 ± 8.99 years (range 19-42 years). In both groups, males predominated in terms of gender (75% in group H and 85% in group P). In Group-H, most of the patients had left side involvement and in Group-P, most of the patients had right side involvement. The mean height in Group-H was 169.00 ± 9.07 cm and in Group-P, it was 168.99 ± 7.58 cm. The mean weight in Group-H was 65.45 ± 8.60 kg and in Group-P, it was 67.31 ± 8.38 kg. In both groups, majority of patients sustained injury due to road traffic accident, and sports related injuries were relatively less in our study. The average graft diameter of Group H was 10.5 ± 0.52 mm and that of Group P was 10.6 ± 0.41 mm.

Table No. 1: - Summary of Patient Data.

Table No. 2: - Comparison of mean Lysholm Score between the two groups.

Unpaired‘t’ test applied. P value <0.05 was taken as statistically significant

In both groups, the mean Lysholm score showed an improvement over the period of follow-ups, from preoperative to 6 months, but the mean differences in Lysholm scores between the two groups at each follow-up were found to be statistically not significant.

Table No. 3: - Comparison of mean IKDC Score between the two groups.1.

Unpaired‘t’ test applied. P value <0.05 was taken as statistically significant

 In both groups, the mean IKDC score showed an improvement over the period of follow-ups, from preoperative to 6 months, but the mean differences in IKDC scores between the two groups at each follow-up were found to be statistically not significant.

Table No. 4: - Comparison of postoperative complications between the two groups.

Fisher’s exact test applied. A P value of <0.05 was taken as statistically significant

In Group-H, 6 (20%) patients complained of knee stiffness and 3 (10%) patient required arthroscopic debridement due to infection.  In Group-P, 3 (10%) patients complained of knee stiffness and 3 (10%) patient required arthroscopic debridement due to infection. The incidence of knee stiffness was comparable between the two groups (Fisher’s exact test P value = 0.343) and similarly, the incidence of requirement of arthroscopic debridement was also comparable between the two groups (Fisher’s exact test P value = 1.000). The postoperative complication rate between the two groups was comparable.

Various studies reported good results after ACL reconstruction with the peroneus long us tendon, in terms of both functional outcome and knee stability. ^[7] Our study supports that assertion. In this study functional outcome and donor site morbidity comparing PL and HST tendon autograft were evaluated which showed that the PL tendon can be used in single-bundle ACL reconstruction with good results at 1-year follow up.

               Another study by Angthong mentioned donor site morbidities like reduced peak torque eversion and inversion, decreased ankle function and concerns about ankle stability inthePLgroup. ^[8] But in our study, the mean ankle version strength showed no statistical difference at the donor site compared to contra lateral normal ankle aversion. No patients had any ankle instability or reduced ankle movements. The ankle function was good in the PL group (AOFAS mean was 96.43±3.13) at the end of 1 year. A similar study was done by S. Rhatomy et al. also showed similar results inAOFAS score atend of 1 year without significantly affecting the ankle functions. ^[9]

               A study by Kerimoglu, PL has a minor effect in carrying the arch of the foot. Usually, PB and abductor digiti minimi maintain lateral longitudinal arch. Abductor hallucis, tibialis posterior and flexor pollicis longus look after medial longitudinal arch. Adductor pollicis and tibialis posterior maintain the transverse arch of the foot. ^[10] According to the literature, PL has no appreciable influence in maintaining the arch and stability of the foot. In our study, we have observed that none of the patients had ankle instability and loss of arch architecture at the end of 1 year.

               In our study, Anterior kneeling pain was also found in about 27% of patients after hamstring tendon harvesting. A similar study done by S.Rhatomy et al. observed 6% of patients developed anterior kneeling pain. ^[11] This symptom can be apprehension in patients where the daily routine includes kneeling on the ground as part of their religious practice which could lead to significant morbidity and reduced quality of life.

               A study by Adachi N stated that the patients who underwent HST graft for ACL reconstruction, more loss of active knee flexion angle was observed and more peak torque angle was shifted to a shallow angle, suggesting that the HST strength may be weaker at the deep flexion angle. ^[12] In this study, we have seen that knee flexion strength reduced in the HST group at the end of 1 year compared to the normal contralateral knee which could be attributed to sacrificing the HST knee flexion component. But in the PT group, there was no decrease in knee flexion strength but instead, knee flexion improved.

               Rhatomy et al. used a hand dynamometer for measuring plantar flexion and eversion in patients who underwent PL tendon usage for ACL reconstruction. They observed that at end of 6 months there was no difference in the plantar flexion and eversion strength compared to the normal contralateral side. ^[13] In this study, there was no statistical difference in plantar flexion and eversion strength of the donor side ankle compared to the normal contralateral ankle at the end of 1-year follow-up. This evidence shows that PL can be used as a promising graft with no effect on ankle eversion and plantar flexion power.

               PL tendon along with PB tends to dispense pressure over the forefoot. Karanikas found no difference in isokinetic strength for first ray plantar flexion of donor versus contralateral normal ankle. ^[14] In this study, similar observations were noted. This could be probably because of intact PB and tenodesis of distal stump of PL to PB. Otis et al. stated that PB is a more efficient evertor at the ankle joint and continues to be even after PL is harvested, and supports the usage of PL as a graft for ACL reconstruction. ^[15]

               A study on 25 patients to evaluate functional outcomes after ACL reconstruction using a triple-layered PL graft. Khajotia observed that there was an improvement in IKDC score with no patients having ankle dysfunction but 2 patients had pressure pain at the graft harvest site at the end of 6 months. ^[16]

               A systematic review and meta-analysis of functional outcome following hamstrings and peroneus longus autograft in ACL reconstruction in 925 patients. Jinshen et al. observed that Lysholm and IKDC score has improved better in peroneus longus group than hamstrings group. There was no difference in FADI but minimally reduced AOFAS score in peroneus longus group. He concluded that peroneus longus can be an ideal graft and can circumvent the complication of imbalance between quadriceps-hamstrings which happens following harvesting the hamstrings tendon. ^[17]

               There was no limitation of ankle eversion and first ray plantar flexion with good ankle motor strength. AOFAS analysis was 100% at end of 1 year and Wiradiputra et al. concluded that peroneus longus can be used as the first option in ACL reconstruction. ^[18]

               A 2 year follow-up of patients who underwent peroneus longus graft for ACL reconstruction by Sholahuddin observed that excellent IKDC, MCS, Tegner-Lysholm score, AOFAS, FADI scores. Good graft diameter was harvested, thigh hypotrophy was less, with excellent ankle function and a better serial hop test result was achieved. ^[19]

               Kusumastutia have done an observational analytical study retrospectively in 75 patients for 1 year. There was an improvement in mean IKDC, MCS, Tegner-Lysholm score, KSS (function), AOFAS and FADI scores at the end of 1 year compared to pre-operative. Eversion and plantar flexion strength were not significantly

different between contralateral normal ankle and donor site. ^[20] Patients had neuropraxia in the HST group and concluded that peroneus longus can be used as a promising graft for ACL reconstruction. ^[21]

               Various studies have shown the ability of peroneus longus usage in ACL reconstruction as an alternative promising graft with minimal or no donor site morbidity apart from other available grafts. However, further studies could focus on measurements of ankle stability and strength and correlate them with functional scores after harvesting the peroneus longus tendon.

               Limitations of the study include; ligament laxity was checked manually which can have inter-observer bias. Instead, a KT1000 arthrometer could be used. Muscle strength measurement with an isokinetic dynamometer would have been more accurate.

PLT has a greater ultimate tensile load, more thickness and length, less graft harvesting time, and almost no donor site morbidity and has a good functional outcome of the knee, making it an effective and safe autograft option. So, PL autograft can be a promising graft of choice in the reconstruction of the ACL and can be much more beneficial in simultaneous multi-ligament injury repair in the knee joint.

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