Regeneration of the hamstring tendons after harvesting for arthroscopic anterior cruciate ligament reconstruction: a histological study in 11 patients

Therapeutic Patient Education after Anterior Cruciate Ligament Reconstruction: Evaluation of the Knowledge and Certitudes with a Self-Report Questionnaire

Therapeutic education aims to help patients acquire skills and knowledge, and to improve psychosocial aspects to manage chronic disease. After anterior cruciate ligament reconstruction (ACLR), only 35 to 60% of the patients are able to go back to their previous sport. Return to sport depends on the motivation of the patient. No therapeutic education has already been proposed. We aimed to evaluate the effect of therapeutic education sessions on knowledge improvement during inpatient rehabilitation after ACLR, compared to patients operated with the same surgical technic, but who had no therapeutic education because of outpatient rehabilitation. Sessions were performed by a multidisciplinary team. The evaluation of the knowledge was performed with a true or false 12-items self-report questionnaire. Fifty-four patients were studied and compared to 54 patients with no therapeutic education. The educated and the non-educated groups were comparable. The number of correct answers increased from 73% before therapeutic education to 95% at the end of the hospitalization (p < 0.001). This improvement persisted over time with 91.5% of correct answers at four months (p = 0.94). The non-educated group had 70% of correct answers. This was significantly lower than the results obtained from the educated group at four months (p < 0.001). It was comparable to the result obtained before therapeutic education (p = 0.91). Therapeutic patient education performed during hospitalization for rehabilitation enables patients to have a better knowledge of the stages from rehabilitation to return to sport and the risks of complication after ACLR.

Is there significant regeneration of the hamstring tendons after harvest for ACL reconstruction? A systematic review of literature

BACKGROUND

Regeneration potential of Hamstring tendons after harvest assumes significant clinical relevance as its use has become widespread today. Methods which best assess the regeneration, extent and type of regeneration, plus issues related to functional loss are important for the surgeon to know. This review looks at the literature to find answers to the above questions.

PURPOSE

To summarize the evidence in support of hamstring tendon regeneration, and the most appropriate modality for evaluation of regeneration. Additionally, to evaluate the regeneration in terms of complete or partial, extent and its impact on strength deficit and functional outcomes.

METHODS

We did a systematic review of literature through specified search engines and identified 30 of 285 studies to be relevant (19 prospective and 11 retrospective).

RESULTS

Evaluation of above data suggests tissue regeneration at harvest sites does occur (78.9% of semitendinosus and 42.7% of gracilis tendons), but this regeneration is variable. No established definition of regeneration exists; MRI is an adequate tool to identify regeneration, while biopsy is confirmative. USG is a cost-effective screening method and can document distal progress of regenerate. Semitendinosus and gracilis tendons regenerate at different rates and extents, and often fuse together, but there is no evidence to state that one regenerates better than the other. Proximal retraction of the muscle-tendon junction occurs, along with some atrophy, which affects function to a variable extent. Strength deficits may persist, but they may not convert to significant functional deficits.

CONCLUSION

There is variable hamstring regeneration after harvest, with poorly defined definition of "regeneration". Some changes in the muscle itself, abnormal distal insertion and absence of regeneration in some are documented, along with strength deficits. Although overall functional deficits have been reported to be minimal, a definite change in the anatomy of the medial hamstrings is a factor to be kept in consideration. More information is needed about the long-term consequences.

Tendon regeneration and muscle hypotrophy after isolated Gracilis tendon harvesting - a pilot study

Purpose

The gracilis tendon (GT) is a commonly used autologous graft in Orthopaedic surgery. The majority of information on knee function and outcomes after hamstring harvest is related to both semitendinosus and GT harvest. Little is known regarding isolated harvest of a GT. It was hypothesized that isolated GT harvest would lead to altered gait patterns (e.g. augmented anterior-posterior translation or rotation in the tibiofemoral joint) and consequently a higher prevalence of cartilage lesions and meniscal tears in knees.

Methods

GT harvesting was performed on patients with chronic acromioclavicular joint instability without previous knee injuries or surgeries. MRI of both knees and thighs were performed. Knee MRI were evaluated using the Whole-Organ Magnetic Resonance Imaging Score (WORMS). Inter- and intraobserver reliabilities, cross-sectional areas of different muscles, fatty infiltration of the gracilis muscle (GM) and GT regeneration were evaluated. The contralateral limb served as reference. The observers were blinded towards the identity of the patients and the operatively treated side.

Results

After a mean time of 44 months after surgery testing was performed on 12 patients. No significant side-to-side differences were found using WORMS, although there was a trend towards increased cartilage lesions after GT harvest (median healthy knee 4.8 and GT harvested knee 7.8 p = 0.086). Inter- and intraobserver repeatability was high with 0.899 (95% confidence interval (CI) 0.708–0.960) and 0.988 (95% CI 0.973–0.995), respectively. A significant hypotrophy of the GM with a mean decrease of 25.3%, 18.4% and 16.9% occurred at 25% (p = 0.016), 50% (p = 0.007) and 75% (p = 0.002) of the length of the femur from distal. No compensatory hypertrophy of other thigh muscles or increased fatty infiltration of the GM was found. Tendon regeneration took place in eight out of 12 patients. In case of regeneration, the regenerated tendon inserted in a more proximal place.

Conclusion

Isolated harvest of the GT for shoulder procedures did not affect knee MRI significantly indicating therefore in general suitable graft utilization for surgeries outside of the knee. GT regenerated in most patients with just a more proximal insertion and a hypotrophy of the muscle belly.

[Anatomic stabilization of chronic lateral instability of the ankle : Gold technique]

OBJECTIVES

Anatomical reconstruction of the lateral ligament complex in the ankle.

INDICATIONS

Chronic lateral ankle instability.

CONTRAINDICATIONS

Severe osteoarthritis, obesity, hindfoot varus, general contraindications (infection, circulatory disorders, diabetic foot syndrome).

SURGICAL TECHNIQUE

Anatomical V‑shaped reconstruction of the lateral ligament complex with half of the peroneus brevis tendon and additional retinaculum stabilization.

POSTOPERATIVE MANAGEMENT

Lower leg orthesis (e. g. protect.CAT Walker, medi GmbH, Bayreuth, Germany) for 6 weeks. Week 1-2, no weight bearing, no active pro- and supination. Starting in week 3-4, begin with partial weight bearing, pain adapted. Starting in week 7, free range of motion, begin with progressive training.

RESULTS

Between March 2014 and June 2016, 16 patients (6 female, 10 male) were treated with the above-named technique. Average age was 32.8 years (range 17.9-57.1 years). Ten patients completed the 6‑ and 12-month follow-ups. None of these 10 patients reported a feeling of instability. In the clinical examination, the lateral ligament complex was stable. Patients showed a free range of motion at the 12-month follow-up.

Semitendinosus Tendon for ACL Reconstruction: Regrowth and Mechanical Property Recovery

Background:

Semitendinosus/gracilis (STG) tendon autograft has been used effectively for restoring knee stability after anterior cruciate ligament (ACL) rupture. Though ACL reconstruction with STG autograft is an effective surgical technique for return to sports, short-term hamstring strength asymmetries exist after surgery. Although imaging evidence has demonstrated regrowth and reorganization of the semitendinosus (ST) tendon, no studies show whether the regrowth is associated with residual muscle function. Continuous shear wave elastography (cSWE) using an external actuator and high–frame rate ultrasound is a promising technique for evaluating the mechanical properties of regrown tendons in vivo.

Purpose:

To demonstrate recovery of the mechanical properties of the hamstring tendons after ACL reconstruction using an STG tendon autograft.

Study Design:

Case series; Level of evidence, 4.

Methods:

Thirteen patients underwent an STG autograft reconstruction after ACL rupture. Regrowth of the ST tendon was confirmed via b-mode ultrasound between 6 and 24 months postreconstruction. The shear elastic (µ₁) and viscosity moduli (µ₂) of the ST tendons were ascertained through cSWE using an external actuator and high–frame rate ultrasound.

Results:

Significant differences in both shear elastic (129.4 vs 73.0 kPa) and viscous moduli (192.6 vs 114.3 Pa·s) existed bilaterally for uninvolved and involved limbs, respectively. Additionally, a positive correlation between time postoperative and shear elasticity was observed (r = 0.60). More than 12 months were required for patients to regain a large percentage of the tendon’s mechanical properties compared with the contralateral side (µ₁, 80.6% at >12 months vs 39.9%; µ₂, 78.7% at >12 months vs 46.0%).

Conclusion:

The imaging and elastography data demonstrate tendon regrowth and recovery of functional biomechanical properties with time. The elastic modulus of the recovered tendon indicates the ability to transmit muscle force across the joint and recovery of semitendinosus function after its use for an ACL graft.

Semitendinosus muscle architecture during maximum isometric contractions in individuals with anterior cruciate ligament reconstruction and controls

BACKGROUND

The most widely used graft as a replacement in anterior cruciate ligament (ACL) reconstruction is the semitendinosus (ST) tendon graft. After harvesting for ACL reconstruction, the hamstring tendon regenerates in most people and becomes similar to normal. The effect of graft harvest on muscle morphology and function remains unclear. The present study aimed to examine the morphology of the ST during isometric contraction after harvesting the ST tendon for ACL reconstruction.

METHODS

Maximal isometric contractions of the knee flexors from two angular positions were performed by 8 participants, at least 1 year after ACL reconstruction with an ST tendon graft and 8 matched controls. Ultrasonographic images were used to measure the pennation angle and muscle thickness of the ST muscle.

RESULTS

There was not a statistically significant difference in pennation angle values between the control group and the group who underwent ACL reconstruction (p >0.05). Muscle thickness was significantly higher in the ACLR group compared with controls (p< 0.05).

CONCLUSIONS

Individuals who underwent ACL reconstruction display a higher ST muscle thickness but similar pennation angle compared with controls. This indicates that ACL reconstruction has an effect on ST muscle belly but effect on force generation capacity is rather limited.

LEVEL OF EVIDENCE

IIb.

The natural history of donor hamstrings unit after anterior cruciate ligament reconstruction: a prospective MRI scan assessment

PURPOSE

The aim of this prospective study was to assess the natural history of the donor hamstrings, compared to the contralateral knee and thigh.

METHODS

In 47 patients who had ACL reconstruction (hamstrings technique), bilateral knees and thighs were investigated using MRI scans, up to 2 years post-operatively.

RESULTS

Tendon regeneration below the knee joint line of the semitendinosus occurred in 30/47 (64 %) patients and of the gracilis tendon in 17/47 (36 %) patients. Insertion of both tendons at the "pes anserinus", with normal anatomic relations, was observed in 5/47 (11 %) patients. Semitendinosus and gracilis donor muscles were found retracted in 41/47 (87 %) patients. In 25/47 (53 %) patients, there was evidence of fatty infiltration of the semitendinosus muscle. All (47/47) (100 %) patients showed semitendinosus muscle atrophy and 41/47 (87 %) patients showed gracilis muscle atrophy, compared to the contralateral limb. High signal intensity on STIR images was observed in the semitendinosus in 22/47 (46 %) patients and in the gracilis muscle in 30/47 (64 %) patients, on MRI examination performed up to 24 months post-operatively.

CONCLUSIONS

The "regenerated" hamstrings tendons most commonly do not regenerate fully anatomically, so they should not be considered as a first choice for re-harvesting in revision ACL reconstruction. The "donor hamstrings muscles" are found to be shorter, contracted, thinner and with a long-term abnormal MRI signal, features which are considered to be related to reduced muscle performance (knee flexion and internal rotation) post-operatively.

LEVEL OF EVIDENCE

II.

Identification of a Remodeled Neo-tendon After Arthroscopic Latarjet Procedure

PURPOSE

To macroscopically, histologically, and radiologically describe a time-dependent remodeling process of a neo-tendon or -ligament in the shoulder after the arthroscopic Latarjet procedure.

METHODS

During follow-up surgery after the arthroscopic Latarjet procedure, 17 shoulders in 16 patients were evaluated for a remodeled tendon-like structure. The mean overall follow-up period was 27.4 months. The mean time between the arthroscopic Latarjet procedure and revision was 11.6 months. All shoulders were evaluated with magnetic resonance imaging, and seven histologic specimens were obtained during revision surgery.

RESULTS

A distinct, oriented strand of tissue was found in 16 of 17 shoulders on revision surgery. Postoperative magnetic resonance imaging analyses showed a signal-free, longitudinal tendon-like structure originating at the tip of the acromion, traversing the space of the former subcoracoid bursa to attach in the course of the transposed conjoint tendon or the proximal short head of the biceps. Histologic analysis of seven specimens showed a characteristic timeline of remodeling.

CONCLUSIONS

A tendon- or ligament-like structure is remodeled between the anterior bottom tip of the acromion and the transposed coracoid process in a time-dependent manner after the arthroscopic Latarjet procedure.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model

OBJECTIVES

The objective of this study was to determine if the use of fascia lata as a tendon regeneration guide (placed into the tendon canal following harvesting the semitendinosus tendon) would improve the incidence of tissue regeneration and prevent fatty degeneration of the semitendinosus muscle.

MATERIALS AND METHODS

Bilateral semitendinosus tendons were harvested from rabbits using a tendon stripper. On the inducing graft (IG) side, the tendon canal and semitendinosus tibial attachment site were connected by the fascia lata, which was harvested at the same width as the semitendinosus tendon. On the control side, no special procedures were performed. Two groups of six rabbits were killed at post-operative weeks 4 and 8, respectively. In addition, three healthy rabbits were killed to obtain normal tissue. We evaluated the incidence of tendon tissue regeneration, cross-sectional area of the regenerated tendon tissue and proportion of fatty tissue in the semitendinosus muscle.

RESULTS

At post-operative week 8, the distal end of the regenerated tissue reached the vicinity of the tibial insertion on the control side in two of six specimens. On the IG side, the regenerated tissue maintained continuity with the tibial insertion in all specimens. The cross-sectional area of the IG side was significantly greater than that of the control side. The proportion of fatty tissue in the semitendinosus muscle on the IG side was comparable with that of the control side, but was significantly greater than that of the normal muscle.

CONCLUSIONS

Tendon tissue regenerated with the fascia lata graft was thicker than naturally occurring regenerated tissue. However, the proportion of fatty tissue in the semitendinosus muscle was greater than that of normal muscle.Cite this article: K. Tabuchi, T. Soejima, H. Murakami, K. Noguchi, N. Shiba, K. Nagata. Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model. Bone Joint Res 2016;5:247-252. DOI: 10.1302/2046-3758.56.2000585.

Hamstring Tendon Regeneration After Harvesting: A Systematic Review

BACKGROUND

Hamstring tendons are often used as autografts for anterior cruciate ligament (ACL) reconstruction. However, no systematic review has been performed describing consequences such as hamstring tendon regeneration rate and determinants of hamstring tendon regeneration.

PURPOSE

To summarize the current literature regarding hamstring tendon rate regeneration, the time course of regeneration, and determinants of hamstring regeneration.

STUDY DESIGN

Systematic review.

METHODS

A search was performed in the Embase, Medline (OvidSP), Web of Science, Cochrane, PubMed, and Google Scholar databases up to June 2014 to identify relevant articles. A study was eligible if it met the following inclusion criteria: tendons were harvested, regeneration at harvest site was assessed, population size was at least 10 human subjects, full-text article was available, and the study design was either a randomized controlled trial, prospective cohort study, retrospective cohort study, or case control study. A risk of bias assessment of the eligible articles was determined. Data describing hamstring tendon regeneration rates were pooled per time period.

RESULTS

A total of 18 publications met the inclusion criteria. The mean regeneration rate for the semitendinosus and gracilis tendons was, in all cases, 70% or higher. More than 1 year after harvesting, 79% (median [IQR], 80 [75.5-90]) of the semitendinosus tendons and 72% (median [IQR], 80 [61-88.5]) of the gracilis tendons were regenerated. No significant differences in regeneration rate could be found considering patient sex, age, height, weight, or duration of immobilization. Results did not clearly show whether absence of regeneration disadvantages the subsequent hamstring function. Five studies measured the regeneration rate at different moments in time.

CONCLUSION

Hamstring tendons regenerated in the majority of patients after ACL reconstruction. The majority of the hamstring tendon regeneration was found to occur between 1 month and 1 year after harvest. No significant determinants for hamstring tendon regeneration could be identified because of a lack of research. The function and strength of the regenerated hamstring remained unclear.

Hamstring Tendon Regeneration After Harvest for Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To assess whether the portions of the semitendinosus and gracilis tendons harvested for anterior cruciate ligament reconstruction have the potential to regenerate and, if so, to evaluate the histologic properties and actual function of this newly formed tissue.

METHODS

We performed a comprehensive search of CINAHL (Cumulative Index to Nursing and Allied Health Literature), Embase, Medline, the Cochrane Central Registry of Controlled Trials, and SPORTDiscus from inception of the databases to July 2014, using various combinations of keywords. Studies focusing on hamstring tendon and muscle regeneration through imaging and histology, as well as on the related functional outcomes, were selected. We included studies assessing evidence of tissue regeneration with imaging (magnetic resonance imaging, 3-dimensional computed tomography, ultrasonography) or with histologic examination of biopsy samples (or a combination thereof).

RESULTS

Nineteen articles were included in this review, with a total of 400 patients observed. The overall rate of tissue regeneration was 86.0%, with similar values shown in most studies regardless of the methodology of the assessment. Biopsy confirmed that the tissue found at the site in 74% of the cases showed typical histologic features of the tendon. The mean modified Coleman Methodology Score of the studies included was 52.7 points, showing a modest methodologic quality for the studies published to date.

CONCLUSIONS

In over 85% of the cases analyzed, regeneration signs of the harvested tendon were found through different imaging and histologic methodologies. A torque deficit in deep knee flexion is always present postoperatively, but the cause for this is still unclear. There is a need for better-designed trials featuring a higher level of evidence to further investigate this matter, and the effects of postoperative care and the surgical approach used on the regeneration process should be analyzed in the future.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II, III, and IV studies.

Histological Evaluation of Regenerated Semitendinosus Tendon a Minimum of 6 Years After Harvest for Anterior Cruciate Ligament Reconstruction

Background:

Semitendinosus (ST) and/or gracilis (G) autografts are the most used grafts for anterior cruciate ligament (ACL) surgery. The tendons have been shown to be able to regenerate but with focal areas of scar tissue in the short term. There are no long-term histological studies of the regenerated tendons.

Hypothesis:

In the long term, the regenerated ST tendon normalizes and has a similar histology as the contralateral nonharvested tendon.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

Eighteen patients (8 female, 10 male) who underwent ACL surgery using ipsilateral ST/G tendon autografts were included in this study. Percutaneous specimens were obtained from the regenerated ST tendon and the contralateral nonharvested ST tendon under ultrasonographic guidance at a median of 8.4 years (100.5 months; range, 77-129 months) after the harvest procedure. Specimens from the nonoperated side served as controls. The histology and presence of glycosaminoglycans (GAGs) were assessed using a light microscope and a semiquantitative grading system.

Results:

Thirty-six biopsies were obtained (2 biopsies from each patient). In 5 biopsies, the amount of tissue was too small to analyze in the light microscope, and 1 patient had been operated on bilaterally and was therefore excluded. In total, 24 biopsies were included in the histological analysis. In overall terms, there were no significant differences between the regenerated and nonharvested ST tendon in terms of fiber structure, cellularity, vascularity, and level of GAGs a minimum 6 years after harvest of the ST tendon. However, 3 of the regenerated tendons displayed a loss of fiber structure.

Conclusion:

The ST tendon regenerates and may regain a histological appearance similar to that of the nonharvested contralateral tendon, as seen in this study a median of 8.4 years after harvesting. However, in some tendons, loss of fiber structure was found.

Evaluation of hamstring muscle strength and morphology after anterior cruciate ligament reconstruction

This study aimed to clarify the relationship between knee flexor strength and hamstring muscle morphology after anterior cruciate ligament (ACL) reconstruction using the semitendinosus (ST) tendon and to determine the causative factors of decreased knee flexor muscle strength. Fourteen male and ten female patients who resumed sports activities after surgery participated in the experiment. Isometric knee flexion torque was measured at 30°, 45°, 60°, 90°, and 105° of knee flexion. Magnetic resonance imaging (MRI) was used to calculate ST muscle length and hamstring muscle volume, and to confirm the status of ST tendon regeneration. The correlation between the MRI findings and flexor strength was analyzed. Regenerated ST tendon was confirmed in 21 of the 24 patients, but muscle volume (87.6%) and muscle length (74.5%) of the ST in the operated limb were significantly smaller than those in the normal limb. The percentage of the knee flexion torque of the operated limb compared with that of the normal was apparently lower at 105° (69.1%) and 90° (68.6%) than at 60° (84.4%). Tendon regeneration, ST muscle shortening, and ST muscle atrophy correlated with decreased knee flexion torque. These results indicated that preserving the morphology of the ST muscle-tendon complex is important.

Structural and functional analysis of the semitendinosus tendon after harvest for soft tissue reconstructive procedures: a dynamic ultrasonographic study

PURPOSE

To assess the potential for regeneration of the hamstring tendons after harvesting for various soft tissue reconstructive procedures, this study uses dynamic, high-resolution ultrasound to evaluate the presence of any tissue in the harvest gap and to characterize tissue functionality.

METHODS

Patients who underwent ACL reconstruction using ipsilateral hamstring autograft were identified in the database of a single surgeon. Dynamic 12-MHz sonographic imaging was used to evaluate the ipsilateral and contralateral (control) semitendinosus tendons from their insertion sites to proximal muscle bellies. The presence or absence and echogenicity of tissue in the harvest defect, tissue appearance, degree of retraction of the proximal tendon stump, thickness of gap tissue, and motion of the proximal tendon stump were recorded. Data were analysed with Wilcoxon-Mann-Whitney, sign or binomial tests, with significance of P < 0.05.

RESULTS

Eighteen knees in 15 patients (aged 17-51 years) were studied. The proximal amputated stump was retracted an average of 9.0 ± 7.6 cm (range, 0-18 cm; P = 0.0063). With dynamic testing, 9 of 15 knees demonstrated decreased excursion of the proximal tendon stump when compared to the native, contralateral muscle-tendon unit (P = 0.0039). Tissue was detected in the harvest gap in nine knees, five of which had harvest gap tissue with a disorganized appearance compared to the native tendon (P < 0.0001). Six of these nine knees had tissue in the gap demonstrating either less or no excursion with active knee flexion when compared to the native, contralateral side (P = 0.0313).

CONCLUSIONS

The presence of tissue in the harvest gap after ACL reconstruction is variable. When tissue is present, there is proximal retraction of the musculotendinous junction and disorganized appearance of the tissue that does not demonstrate normal excursion or physiological function similar to the native muscle-tendon unit.

LEVEL OF EVIDENCE

Case series, Level IV.

Regeneration of hamstring tendons after anterior cruciate ligament reconstruction

PURPOSE

Primary aim of the study was analysis of hamstring tendon regeneration after anterior cruciate ligament reconstruction (ACLR). Secondary aim was analysis of isokinetic muscle strength in relation to hamstring regeneration. The hypothesis was that regeneration of hamstring tendons after ACLR occurs and that regenerated hamstring tendons contribute to isokinetic hamstring strength with regeneration distal to the knee joint line.

METHODS

Twenty-two patients scheduled for ACLR underwent prospective MRI analysis of both legs. MRI parameters were tendon regeneration and morphology, muscle retraction and muscle cross-sectional area. A double-blind, prospective analysis of isokinetic quadriceps and hamstrings strength was performed.

RESULTS

Regeneration of the gracilis tendon after ACLR occurred in all patients. Regeneration of the semitendinosus tendon occurred in 14 patients. At 1 year, the surface area of the semitendinosus and gracilis muscle decreased compared to both preoperatively (P < 0.01) and the contralateral leg (P < 0.01). The cross-sectional area of the semitendinosus muscle decreased in the absence of tendon regeneration (P = 0.05). The cross-sectional area of the gracilis muscle was greater in case of regeneration distal to the joint line (P = 0.01). Muscle retraction of the semitendinosus muscle was increased in case of nonregeneration (P = 0.02). There was no significant relationship between isokinetic flexion strength and tendon regeneration.

CONCLUSION

Hamstring tendons regenerated after harvest of both semitendinosus and gracilis tendons for ACLR. There was no relation between isokinetic flexion strength and tendon regeneration.

Inducement of semitendinosus tendon regeneration to the pes anserinus after its harvest for anterior cruciate ligament reconstruction-A new inducer grafting technique

Purpose

To investigate the usefulness of the “inducer grafting” technique for regeneration of the semitendinosus (ST) tendon after its harvest for anterior cruciate ligament (ACL) reconstruction.

Methods

Twenty knees of 20 patients (mean age at the time of surgery, 23.1 years) underwent ACL reconstruction with a double bundle autograft using the ST tendon (7 patients) and the ST + the gracilis (G) tendons (13 patients).

“Inducer grafting” technique

After harvesting the ST tendon, a passing pin with a loop thread is inserted along with the tendon stripper. The passing pin is pulled out from the medial thigh and the loop thread retained. As an inducer graft, the ST tendon branch is used. After the ACL graft has been secured, the inducer graft is sutured to the pes anserinus and the proximal end passed through by pulling the thread out. Then the inducer graft is placed within the tendon canal. The mean follow-up period was 15 months. The presence and morphology of the regenerated ST tendon were examined by MRI. And the isometric hamstring strength was examined at 45°, 90° and 120° of knee flexion.

Results

One month after the operation in all the patients, MRI demonstrated a low-intensity structure at the anatomical location of the ST, at the level of the superior pole of the patella and the joint line, apparently representing the regenerated ST tendon. Four months after the operation, the distal portion of the regenerated ST tendon had reached the pes anserinus in all patients. Twelve months after the operation, the regenerated ST tendon was hypertrophic in 19 of the 20 patients (95%). The isometric knee flexion torque of the ACL-reconstructed limb was significantly lower at 90° and 120° compared with the contralateral limb.

Conclusion

These results suggest that the “inducer grafting” technique is able to improve the regeneration rate of the harvested ST tendon and promote hypertrophy of the regenerated ST tendon, extending all the way to the pes anserinus. However, this technique couldn’t improve the deficits in knee flexion torque after ACL reconstruction.

Relationships among tendon regeneration on MRI, flexor strength, and functional performance after anterior cruciate ligament reconstruction with hamstring autograft

BACKGROUND

There are numerous reports on hamstring tendon regeneration after harvest for anterior cruciate ligament (ACL) reconstruction. However, few studies have evaluated the relationships among the magnetic resonance imaging (MRI) findings of hamstring regeneration, muscle strength, and functional results.

PURPOSE

This study evaluates the correlations among the hamstring regeneration on MRI, flexor strength, and functional performance after hamstring tendon harvesting in ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We enrolled 45 patients who underwent primary ACL reconstruction using hamstring tendon autografts and in whom flexor strength, functional performance, and preoperative and postoperative MRI results were evaluated at least 2 years postoperatively. Isokinetic flexion strength was tested in the standard and prone positions. We evaluated the differences in flexor strength and functional performance according to the number of regenerated tendons. The correlation between the MRI findings (the number of regenerated hamstring tendons and proximal shift of the musculotendinous junction) and the functional performance and flexor strength was analyzed.

RESULTS

The patients were divided into 3 groups according to the regeneration of the hamstring tendons on MRI: both semitendinosus and gracilis tendons regenerated (group SG), only 1 tendon regenerated (group O), and no tendon regenerated (group N). Significant differences were found in the flexor deficit between group N and groups SG and O on the standard and prone position isokinetic tests. There was a significant correlation (ρ = -.472) between the number of regenerated hamstring tendons and the carioca test result. The proximal shift significantly correlated with the flexor deficit in the prone position isokinetic test (semitendinosus, r = .449; gracilis, r = .366).

CONCLUSION

Hamstring tendons regenerated after harvest for ACL reconstruction in a high proportion of the patients. The flexor strength with both the standard and prone position isokinetic tests differed in the 3 groups. The number of regenerated hamstring tendons was significantly correlated with performance on the carioca test. Proximal shifting of the musculotendinous junction was significantly correlated with flexor deficit on the hyperflexion isokinetic test.

Magnetic resonance imagination of the peroneus longus tendon after anterior cruciate ligament reconstruction

Several studies report that tendons can regenerate after harvesting. These studies have been performed especially in patellar and hamstring tendons. At our institution, 10 cm length of full thickness peroneus longus tendon has been harvested to reconstruct torn anterior cruciate ligament since 1997 as a different graft source. The aim of this study was to investigate whether the peroneus longus tendon used the anterior cruciate ligament reconstruction has a regeneration potential or not. Twelve patients, who had originally undergone harvesting of the peroneus longus tendon for the primary surgery of the anterior cruciate ligament reconstruction, underwent magnetic resonance imaging (MRI). Images of both legs were acquired simultaneously with the use of the scanner's extremity coil, as we aimed to compare harvested peroneus longus tendon with the other leg's peroneus longus tendon (healthy side) for evaluation of the regeneration potential. The average age of the patients was 31 years. There were eight right and four left legs. The average time interval was 52 months between ligament surgery and MRI. In all patients, a varying amount of the regeneration of the peroneus longus tendon was seen on the MRI images. Although the extent of PLT regeneration in proximal sections seemed better than in mid- and distal sections, there was no statistical difference between sections (P = 0.130). These data show that the peroneus longus tendon has a regeneration potential after harvesting for anterior cruciate ligament reconstruction.

Minimizing internal rotation strength deficit after use of semitendinosus for anterior cruciate ligament reconstruction: a modified harvesting technique

PURPOSE

The purpose of this study was to test a new method of harvesting semitendinosus tendon during anterior cruciate ligament reconstruction that would allow an anatomic reinsertion of the regenerated tendon and minimize postoperative internal rotation strength loss.

METHODS

We prospectively selected 35 patients surgically treated for anterior knee instability. The patients were randomly assigned to either the study group (group A) (19 patients) or the control group (group B) (16 patients). A modified harvesting technique of the semitendinosus, which reserves its distal insertion, was performed in group A, with the aim to allow a better postoperative recovery of flexion and internal rotation strength. Patients in group B underwent a "standard" harvesting technique. All patients were postoperatively evaluated by clinical examination, isokinetic tests, and magnetic resonance imaging.

RESULTS

At a follow-up of 25 months, all patients showed satisfactory postoperative knee stability. Isokinetic tests showed a significant deficit in internal rotation strength at 60 degrees /s in patients in group B (84.60% v 97.37% in patients in group A). No deficits were found in group A. Magnetic resonance imaging evaluations showed a higher percentage of regenerated semitendinosus in group A patients (100%) than that in group B patients (50%) at the joint line level. In group A, the site of reinsertion was found to be on the pes anserinus in 71% of the patients and in the posteromedial corner of the tibial plateau in the other 29%; in group B, a distal signal was detected in 50% of the patients, which was at the posteromedial corner of the tibia in every case.

CONCLUSIONS

This study seems to show that the proposed harvesting technique could minimize the postoperative loss of strength in internal rotation after anterior cruciate ligament reconstruction with hamstrings.

LEVEL OF EVIDENCE

Level I, high-quality therapeutic randomized controlled trial.