Quantifying donor site morbidity in anterior cruciate ligament reconstruction using peroneus longus tendon autograft

INTRODUCTION

The anterior cruciate ligament (ACL) is commonly damaged in the knee joint, affecting approximately 1.5–1.7% of primary ACL cases annually in the population.^[1] ACL injuries can be treated with either conservative or surgical methods. Conservative treatment, involving knee bracing and physical therapy, is typically recommended for patients with ACL sprain or incomplete tears. However, surgical intervention is usually necessary for patients with complete ACL tears and may involve reconstruction of the ligament using an allograft or autograft.^[2] ACL reconstruction (ACLR) can be performed with both allografts and autografts. Allografts have the disadvantages of being more expensive, having delayed incorporation, being more likely to transmit diseases, and being more likely to have immunological reactions.^[3] Reconstructive surgery involving the utilization of a frequently sourced graft from the patient’s muscle (autograft) has gained widespread popularity as a procedure for treating an ACL injury, ensuring the preservation of knee function and stability.^[4] ACLR aims to restore the knee’s biomechanical and kinematic functions to a level similar to its native function.^[5]

The current preferred option for ACLR around the globe is using a hamstring tendon autograft because it provides better tensile strength than the bone-patellar tendon-bone (BPTB) autograft. However, the inconsistent muscle diameter in different individuals can result in suboptimal outcomes or potential graft failure.^[6] Alternative autograft options for ACLR consist of BPTB, quadriceps tendon, and tensor fascia lata.^[7] The BPTB autograft is a gold standard in ACLR. The biomechanical strength of BPTB is comparable to that of native ACL. BPTB enables early active-safe rehabilitation without increasing graft failure risk and has a favorable long-term outcome. However, BPTB can cause morbidity at the graft harvesting site, such as patellofemoral discomfort, loss of mobility, and patellar fracture.^[8] Our population faces unique functional demands because individuals in our culture and religion need to perform high-flexion knee activities such as kneeling and squatting for social and religious customs for extended periods. Hence, they need to flex the knee up to 150°–165°. At this much flexion, it exceeds the usual population by an average of 15°.^[9] Hence, donor site morbidity is a very important consideration in our population, and graft sites remote from the ACLR site will address this problem better. The disadvantages of the regularly utilized autografts discussed above necessitate the search for an alternate graft material. An ideal graft would have a reasonable degree of strength, a suitable size, and be quickly and safely harvested. The peroneus longus tendon (PLT) is long and strong enough to be used as an autograft of choice to reconstruct ACL.^[3] The PLT is obtained from a location near the lateral ankle, specifically proximal and posterior to it.^[10]

Kartus et al.^[11] classified donor site morbidity into three categories: General pain, specific discomfort, and late tissue reactions. Various methods exist for evaluating issues related to donor site morbidity. Valuable clinical tools include (1) evaluating strength through functional tests such as the 1-leg-hop test or dynamometers such as Cybex, assessing range of motion (ROM) loss, examining knee-walking ability, and measuring disturbance or sensory loss in the donor site area or the region innervated by nerves passing through the donor site; (2) conducting radiographic evaluations using standard radiographs, magnetic resonance imaging, computed tomography, and ultrasonography; and (3) performing histologic and biochemical analyses on samples obtained from the donor site area.^[11]

The study aimed to determine the donor site morbidity in patients undergoing ACLR using PLT autograft.

MATERIALS AND METHODS

This prospective cohort study was performed at the orthopedic department of Pakistan Atomic Energy Commission General Hospital, Islamabad, from July 2021 to July 2023 after obtaining approval from the Institutional Review Board (IRB), vide reference number PGHI-IRB (Dme)-RCD-06-024. A total of 150 patients gave consent to enroll in this study after ACLR surgery using PLT autograft.

RESULTS

A total of 150 patients enrolled in this study after ACLR surgery using PLT autograft. Of the patients, 142 (94.6%) were male and 8 (5.4%) were female. The mean age of the patients was 32.53 ± 4.78 years.

Pain and loss of ROM around the ankle were reduced after six months [Table 1] as compared to three months and six weeks, that is, P < 0.05. Muscle power of the patients was increased after six months (n = 152; 94.0%), followed by three months (127 (84.7%) and six weeks (n = 120; 80.0%) with significant P < 0.001.

In the 6^th month, 133 patients (88.7%) were able to jog without any discomfort around the ankle joint during the ¹st min of jogging, but 17 patients (11.3%) started jogging after six months without any discomfort at the ankle joint during the 1^st min of jogging (P < 0.001).

DISCUSSION

This study used the PLT as an autograft for ACLR in patients with acute ACL rupture. Various experiments have shown that the PLT offers the highest tensile strength. Shi et al.^[12] discovered that the anterior half of the PLT possesses sufficient length and strength to be a viable autograft option for ACLR. Restoring joint stability and alleviating symptoms are the immediate objectives of ACLR. In the long run, the ultimate goals involve enabling individuals to resume their previous level of activities and mitigating the risk of future onset of osteoarthritis.^[13,14] Many studies indicate that the results of ACLR surgeries are frequently below expectations. Instability after the surgery can continue, potentially resulting in additional harm to the meniscus or cartilage. Over time, this can lead to the development of knee arthritis. Recent research findings highlight that just 37% of patients who had ACLR attained full recovery of their knee’s normal function.^[15] Only 65–70% of individuals return to the pre-injury level of sports activity after ACLR.^[16] Common signs after ACLR include discomfort in a specific area, reduced sensation, and difficulty kneeling or walking on the knees. As stated in available sources, anterior knee pain could be associated with three factors: Decreased mobility, limited hyperextension post-ACLR, and damage to the infrapatellar nerve caused by the skin incision.^[17,18]

Out of 150 patients, 113 (975.35%) patients had mild pain around the ankle, 30 (20%) patients had moderate pain, and 7 (4.7%) had severe pain in the 6^th week. In the 3^rd month, the number of patients with severe pain decreased to 5 (3.3%), patients with moderate pain were 19 (12.7%), and the patients with mild pain were 126 (84.0%). In the 6^th month after ACLR, only 3 (2%) patients had severe pain, 12 (8.0%) had moderate pain, and 135 (90.0%) had mild pain. The ²nd parameter ROM was accessed using the AOFAS ankle hindfoot scale in which out of 150 patients, 83 (55.3%) patients had a mild loss, 44 (29.3%) had a moderate loss, and 23 (15.4%) had severe loss of ankle joint (plantar flexion and dorsiflexion) motion at the 6^th week after the ACLR surgery. In the 3^rd month, 117 (78.0%) patients had a mild loss of motion, 27 (18.0%) had a moderate loss, and 6 (4.0%) had severe loss of motion. However, at the 6^th month after the ACLR, only 4 (2.7%) patients were having severe loss of motion, 6 (4.0%) patients were having moderate loss, and 140 (93.3%) patients were having mild loss of motion. Similarly, the loss of range of hind foot (eversion and inversion) motion also decreases in the 6^th month compared to 3^rd month and 6^th week.

The third parameter, muscle power, was measured using the MRC muscle power scale. The muscle power was increased in the patients after the 6^th month (n = 152; 94.0%), followed by the 3^rd month (n = 127; 84.7%) and 6^th week (n = 120; 80%). In the fourth parameter, we assessed the patients based on the ACL RSI scale, in which 133 (88.7%) patients returned to jogging without discomfort around the ankle joint during the ¹st min of jogging before six months, and 17 (11.3%) returned to jogging without discomfort around ankle joint during the ¹st min of jogging after 6^th month.

Based on previous studies, removing the PLT is not expected to affect the foot and ankle function substantially.^[19] Our findings support this assertion. The main function of the peroneus longus muscle is to rotate the foot outward and flex the first metatarsal bone downward.^[20,21] There are concerns that removing this tendon may not only decrease eversion strength and plantar flexion but also result in greater ankle instability. However, our research showed that ankle strength and ROM were similar before and after the PLT extraction.

CONCLUSION

ACLR using the PLT autograft resulted in a superb functional outcome, smooth rehabilitation with the early return to sports, and minimal complications at the donor site. This highlights the PLT as a viable option primary option for grafting in ACLR surgeries in non-athletic population.