Risk of overconstraining femorotibial rotation after anatomical ACL reconstruction using bone patella tendon bone autograft.

INTRODUCTION: Numerous studies have focused on the anteroposterior stability after anterior cruciate ligament (ACL) reconstruction, with less emphasis on rotational stability. It has been hypothesized that bone patella tendon bone (BTB) autograft for ACL reconstruction restores knee rotation closely to normal due to its comparable fiber orientation to the native ACL. MATERIALS AND METHODS: Twenty patients with unilateral ACL rupture and an uninjured contralateral knee were included in this study. The ACL was reconstructed using the medial third of the patellar tendon. Tunnel placement was controlled by fluoroscopy. Implant-free press-fit graft fixation was used on both femoral and tibial side. Bone blocks were carefully placed to restore fiber orientation of both the anteromedial and posterolateral bundle, similar to the native ACL. Rotatory laxity of both knees was measured at 0° and 25° of flexion pre- and post-surgery, using an active opto-electronical motion-analysis system (LUKOTRONIC AS 100®). All measurements were performed under general anesthesia during surgery. RESULTS: Knee rotation was reduced significantly in both 0°and 25° of flexion following ACL reconstruction (p < 0.001). The side to side difference (SSD) of the rotatory laxity in extension was greater in the ACL-deficient knee (14.9° ± 8.9°), but decreased significantly after ACL reconstruction (- 5.9° ± 7.7°, minus value means less than in the uninjured knee). There was a similar finding at 25° of knee flexion where greater rotation of the ACL-deficient knee (5.7° ± 10.3°) prior to surgery changed to lower degree of rotation after surgery (- 11.3° ± 8.4°) in comparison to the uninjured knee. CONCLUSIONS: ACL reconstruction with a BTB graft in anatomical position using press-fit implant-free fixation is able to restore rotatory knee stability close to the intact contralateral knee. Despite the fact that the BTB graft offers fiber orientation close to the natural ACL, the surgeon should be aware of the potential risk of over-constraining the knee in terms of rotation. LEVEL OF EVIDENCE: II.

Bracing can partially limit tibial rotation during stressful activities after anterior crucial ligament reconstruction with a hamstring graft.

BACKGROUND: Hamstring graft has substantial differences with BPTB graft regarding initial mechanical strength, healing sequence, and vascularization, which may imply that a different approach during rehabilitation period is required. The purpose of this study was to investigate the influence of knee bracing on tibial rotation in ACL-reconstructed patients with a hamstring autograft during high loading activities. The hypothesis was that there would be a decrease in tibial rotation in the ACL-reconstructed braced knee as compared to the unbraced knee. METHODS: Twenty male patients having undergone unilateral ACL reconstruction with a semitendinosus/gracilis autograft were assessed. Kinematic data were collected with an eight-camera optoelectronic system during two stressful tasks: (1) descending from a stair and subsequent pivoting; and (2) landing from a platform and subsequent pivoting. In each patient, three different experimental conditions were evaluated: (A) wearing a prophylactic brace (braced condition); (B) wearing a patellofemoral brace (sleeved condition); (C) without brace (unbraced condition). The intact knee without brace served as a control. RESULTS: Tibial rotation was significantly lower in the intact knee compared to all three conditions of the ACL-reconstructed knee (P≤0.01 for both tasks). Presence of a brace or sleeve resulted in lower tibial rotation than in the unbraced condition (p=0.003 for descending/pivot and P=0.0004 for landing/pivot). The braced condition resulted in lower rotation than the sleeved condition for descending/pivoting (P=0.031) while no differences were found for landing/pivoting (P=0.230). CONCLUSION: Knee bracing limited the excessive tibial rotation during pivoting under high loading activities in ACL-reconstructed knees with a hamstring graft. This partial restoration of normal kinematics may have a potential beneficial effect in patients recovering from ACL reconstruction with a hamstring autograft. LEVEL OF EVIDENCE: Level III, case-control therapeutic study.

Diagnostic value of the clinical investigation in acute meniscal tears combined with anterior cruciate ligament injury using arthroscopic findings as golden standard.

INTRODUCTION: The main purpose of our study was to evaluate the accuracy of clinical investigation for meniscal tears associated with ACL injuries. We hypothesized that combined ACL injury can decrease the accuracy of clinical examination in acute onset. MATERIALS AND METHODS: One hundred and thirty-seven patients with a mean age of 28.5 years (from 12 to 55) were prospectively examined for acute combined ACL and meniscal injuries, between March and November 2012 at our department. For meniscal tears, clinical examination was performed using McMurray test, Apley test and medial and lateral joint line tenderness. The diagnoses of ACL tear were made using Lachman test, jerk test and pivot-shift test, anterior drawer test and KT-2000 side-to-side difference. Each patient was examined using X-ray and MRI. All the patients underwent arthroscopic surgery performed by the same surgeon within 6 weeks after the injury. Finally, using the arthroscopic findings as gold standard, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of clinical investigation and MRI were evaluated. RESULTS: The specificity of clinical investigation was 63.5 and 46.0 % and the sensitivity was 74.4 and 77.3 % for the medial meniscus and the lateral meniscus, respectively. Overall, the accuracy of the clinical investigation was 70.3 % for the MM and 65.5 % for the lateral meniscus. The accuracy of MRI investigation was 76.4 and 69.5 % for medial and lateral meniscus, respectively. DISCUSSION: In combined acute ACL injury and meniscal tears, we have found a decreased accuracy of the clinical investigation. The remnants of the torn ACL and the synovitis increased the rate of false positives, and it could simulate meniscal tears. However, clinical investigation can provide sufficient information for the treatment decision and MRI can be avoided as a routine diagnostic tool. LEVEL OF EVIDENCE: Level II, prospective study.

Anatomy of the Medial Patello-Femoral Ligament: a systematic review of the last 20 years literature.

BACKGROUND: Although many studies have investigated the anatomy of the Medial Patello-Femoral Ligament (MPFL), some studies have even questioned its existence. In the last 20 years, there is a renewed interest on the role of the MPFL in patello-femoral instability. As a result, several studies have been published that describe the anatomy, function and possible surgical reconstruction of the MPFL. Despite the large amount of literature produced, there is still a lack of consensus on what is its real anatomy as there are currently no systematic reviews on this topic. PURPOSES: Thus, the aim of this review is to systematically report the results in literature regarding in anatomical papers, the existence, size, insertion sites and relationships of this ligament with the other medial structures of the knee. METHODS: We have systematically analyzed anatomical studies currently available in literature between 1980 and December 2012. The search was carried out on Medline, Embase, Cochrane Library and Google Scholar. We checked reference lists of articles, reviews and textbooks identified by the search strategy for other possible relevant studies. RESULTS: The outcomes examined are the presence of the ligament, its size (length, width, thickness), and its patellar and femoral insertions. A total of 312 cadaveric knees were included in the 17 studies; the MPFL was identified in 99% of cases (309). CONCLUSIONS: The consensus is that the MPFL is almost always present in the dissected knees. The size and insertions of the ligament demonstrate great variation between cadavers. LEVEL OF EVIDENCE: Systematic review of anatomical study, Level 1.

Shape and size of the medial patellofemoral ligament for the best surgical reconstruction: a human cadaveric study.

PURPOSE: The aim of this study was to investigate the shape and the attachments of the medial patellofemoral ligament (MPFL) in cadaver specimens to determine an anatomical basis for the best MPFL reconstruction. METHODS: Twenty fresh-frozen knees were used. Dissection protocol implied performing dissections from within the knee joint. We investigated the shape and the attachments between the MPFL and the quadriceps tendon, the patellar and femur insertions, and all the other relationships with the medial soft tissues of the knee. RESULTS: The distal fibers of MPFL were interdigitated with the deep layer of the medial retinaculum. All isolated ligament had a sail-like shape with the patellar side bigger than the femoral side. The femoral insertion, distinct both from medial epicondyle and adductor tubercle, was located at 9.5 mm (range 4-22) distal and anterior respect to adductor tubercle and proximal and posterior to epicondyle. The medial third of the thickness of patella was involved in the insertion. The proximal third of the patella is always involved in the MPFL attachment; in 45% of the cases, it was extended to the medial third and in one case, an extension at the distal third was found. Additionally in 35% (7 cases), it extended to the quadriceps tendon and it were inconstantly attached at the vastus medialis obliques (VMO) tendon and at the vastus intermedius (VI) tendon in an aponeurotic structure. CONCLUSIONS: The MPFL is a distinct structure that goes from patella to femur with a sail-like shape; its patellar insertion, that mostly occur via an aponeurosis tissue with VMO and VI, is at the proximal third of the patella but it may extend in some cases to the medial third patella or to the quadriceps tendon, or very rarely to the distal third of the patella. In the femoral side, the MPFL is inserted in its own site, in most cases distinct both from epicondyle and adductor tubercle, located on average at a 9.5 mm distance distally and anteriorly in respect to the adductor tubercle. Its lower margin was difficult to define. Given the importance of this structure, it must be reconstructed as anatomically as possible in its insertion and in its shape. Many attempts have been made to make functional reconstructions with less than excellent results.

Rupture of anterior cruciate ligament monitored by acoustic emission.

The scope of this study is to relate the acoustic emission (AE) during rupture of human soft tissue (anterior cruciate ligament, ACL) to the mechanisms leading to its failure. The cumulative AE activity highlights the onset of serious damage, while other parameters, show repeatable tendencies, being well correlated with the tissue's mechanical behavior. The frequency content of AE signals increases throughout the experiment, while other indices characterize between different modes of failure. Results of this preliminary study show that AE can shed light into the failure process of this tissue, and provide useful data on the ACL reconstruction.

Endurance markers are related with local neuromuscular response for the intact but not for the ACL reconstructed leg during high intensity running.

AIM: It has been demonstrated that the local neuromuscular response during high intensity exercise has a strong relationship with endurance markers. However, a diminished neuromuscular response has been reported for the operated leg in athletes having undergone anterior cruciate ligament reconstruction (ACLR). The purpose of the present study was to examine the relationships between endurance markers and the EMG response during high intensity running in ACLR athletes. METHODS: Fourteen ACLR soccer players underwent a GXT test to volitional exhaustion and a 10-min bout of high intensity running. During the 10-min bout, EMG data were recorded at the 3rd and 10th minute from the vastus lateralis bilaterally using a telemetric system. The final EMG levels were expressed as a percentage of the initial values. Pearson moment product correlations were used to assess the relationship between the endurance markers of VO2max, velocity at lactate threshold (vLT), velocity at 4mM (V4) and the final EMG levels. RESULTS: Final EMG levels for the intact leg had a very strong relationship with vLT (r=0.77, P=0.001) and a strong relationship with V4 (r=0.68, P=0.008). Final EMG levels for the reconstructed leg had moderate relationship with vLT (r=0.47, P=0.09) and V4 (r=0.52, P=0.06). CONCLUSION: The neuromuscular response of the intact leg during high intensity running shows strong to very strong relationships with endurance markers. Failure of the ACLR leg to present relationships of similar strength may indicate that chronic perturbations modify the ability of the local muscular environment to tolerate sustained high intensity efforts.

ACL injury and reconstruction: Clinical related in vivo biomechanics.

Several researchers including our group have shown that knee joint biomechanics are impaired after anterior cruciate ligament (ACL) injury, in terms of kinematics and neuromuscular control. Current ACL reconstruction techniques do not seem to fully restore these adaptations. Our research has demonstrated that after ACL reconstruction, excessive tibial rotation is still present in high-demanding activities that involve both anterior and rotational loading of the knee. These findings seem to persist regardless of the autograft selection for the ACL reconstruction. Our results also suggest an impairment of neuromuscular control after ACL reconstruction, although muscle strength may have been reinstated. These abnormal biomechanical patterns may lead to loading of cartilage areas, which are not commonly loaded in the healthy knee and longitudinally can lead to osteoarthritis. Muscle imbalance can also influence patients' optimal sports performance exposing them to increased possibility of knee re-injury. In this review, our recommendations point towards further experimental work with in vivo and in vitro studies, in order to assist in the development of new surgical procedures that could possibly replicate more closely the natural ACL anatomy and prevent future knee pathology.

Anterior cruciate ligament reconstruction with a quadrupled hamstrings tendon autograft does not restore tibial rotation to normative levels during landing from a jump and subsequent pivoting.

AIM: Recent research suggested that the anterior curciate ligament (ACL) reconstruction does not restore tibial rotation to normal levels when a bone patellar tendon bone (BPTB) graft is used during high demanding activities. Our goal was to determine if the usage of an alternative graft, as the quadrupled semitendinosus-gracilis (ST/G), restore tibial rotation to normal values in a population of athletically active individuals while performing a usual for their sport activity. METHODS: Eleven subjects, all reconstructed with an ST/G graft, were assessed in vivo, 9 months postoperatively, while they jumped off a 40 cm platform, landed on the ground and subsequently pivoted at 90 degrees. The evaluation period was identified from initial foot contact with the ground, included the pivoting of the ipsilateral leg, and was completed upon touchdown of the contralateral leg. By that time the patients had already returned to their sports activities. RESULTS: The maximum range of motion of the tibial rotation for the pivoting leg, during the evaluation period was found significantly (P=0.0001) larger in the reconstructed leg as compared to the intact contralateral, although both clinical and arthrometer assessments revealed restoration of anterior translation. CONCLUSIONS: It was concluded that ACL reconstruction with an ST/G graft does not restore tibial rotation to normal levels during this high demanding activity. It seems that new surgical techniques are needed to better replicate the actual anatomy and function of the natural ACL in order to address this problem.

Functional outcome after excision of heterotopic ossification about the knee in ICU patients.

The objective of this study was to evaluate the degree of improvement in the range of movement in the knee joint, sitting ability, and overall ambulation in patients with heterotopic ossification of the knee joint who underwent surgical excision of ectopic bone. Between 1999 and 2006, 14 patients (23 joints) with significant heterotopic ossification of the knee joint that required surgery were evaluated. We compared the range of movement in the knee joint, sitting ability, and overall ambulation in the preoperative and postoperative periods using the Fuller and Keenan classification systems. Range of movement increased in 82% of cases (19 knee joints). Sitting ability improved in 13 patients (93%). Postoperatively, ambulation in eight patients (57%) was remarkably superior. In conclusion, resection of heterotopic ossification may significantly improve the range of movement in the knee joint, sitting ability, and overall ambulation.

Electromechanical delay of the knee extensor muscles is not altered after harvesting the patellar tendon as a graft for ACL reconstruction: implications for sports performance.

Although the scar tissue, which heals the donor site defect, has different elasticity from the neighbouring patellar tissue, it remains unclear if this scar tissue can lead to the changes of the electromechanical delay (EMD) of the knee extensor muscles. If such changes do exist, they can possibly affect both the utilization of the stored energy in the series elastic component, as well as the optimal performance of the knee joint movement. The purpose of this study was to investigate the influence of harvesting the patellar tendon during anterior cruciate ligament (ACL) reconstruction and the associated patellar tendon scar tissue development on the EMD of the rectus femoris (RF) and vastus medialis (VM) muscles. Seventeen patients who underwent an ACL reconstruction using the medial third of the patellar tendon were divided in two groups based upon their post-operative time interval. Maximal voluntary contraction from the knee extensors, surface EMG activity, and ultrasonographic measurements of the patellar tendon cross-section area were obtained from both knees. Our results revealed that no significant changes for the maximal voluntary contraction of the knee extensors and for the EMD of the RF and the VM muscles due to patellar scar tissue development after harvesting the tendon for ACL reconstruction. The EMD, as a component of the stretch reflex, is important for the utilization of the stored energy in the series elastic component and thus, optimal sports performance. However, from our results, it can be implied that the ACL reconstruction using a patellar tendon graft would not impair sports performance as far as EMD is concerned.

Hamstring weakness as an indicator of poor knee function in ACL-deficient patients.

Anterior cruciate ligament (ACL) rupture causes instability to the knee joint which leads each patient to a different degree of disability. The purpose of this study was to examine the strength of the quadriceps and the hamstrings in ACL-deficient amateur soccer players at different levels of functional status. Thirty male amateur soccer players were separated into three groups according to their Lysholm score; the high-L1 (Lysholm > or =84), the intermediate-L2 (84> Lysholm > or =72) and the low-L3 (Lysholm <72) knee function groups. The control group consisted of 12 amateur soccer players. The strength of the quadriceps and hamstrings was assessed isokinetically at 60 degrees/s. The quadriceps demonstrated significant deficits of the injured knee compared to the intact knee in all groups, whilst the hamstrings showed significant weakness only in the low function group. Respective percentage deficits in groups L1, L2 and L3 were 13.7%, 16.0% and 18.6% for the quadriceps and 2.4%, 5.6% and 19.2% for the hamstrings. All groups had significant quadriceps weakness which did not differ between the groups. In contrast, the strength deficit of the hamstrings was an indicator of poor knee function, since they were significantly weak only in group L3, which represented patients who clearly failed to compensate for instability symptoms. In groups L1 and L2 the side-to-side differences were within the area of asymmetry measured in the control group. Clinical importance of the results is discussed.

The effects of anterior cruciate ligament reconstruction on tibial rotation during pivoting after descending stairs.

Recent in vitro research suggests that ACL reconstruction does not restore tibial rotation. This study investigated rotational knee joint stability in vivo during a combined descending and pivoting movement that applies a high rotational load to the knee joint. We studied 20 ACL reconstructed patients (bone-patellar tendon-bone graft) and 15 matched controls with a six-camera optoelectronic system performing the examined movement. In the control group the results showed no significant differences in the amount of tibial rotation between the two sides. No significant differences were also found between the contralateral intact leg of the ACL group and the healthy control. However, a significant difference was found within the ACL reconstructed group and between the reconstructed and the contralateral intact leg. Therefore ACL reconstruction may not restore tibial rotation even though anterior tibial translation has been reestablished.

The presence of proprioceptive mechanoreceptors in the remnants of the ruptured ACL as a possible source of re-innervation of the ACL autograft.

This study investigated the presence of neural mechanoreceptors in the remnants of the ruptured ACL as a possible source of reinnervation of the ACL autologous graft. The remainder of the torn ACL was selected for further histological investigation from 17 patients during ACL reconstruction 3 months to 3.5 years after injury. Perioperatively two types of ACL remnant were identified. Fifteen patients had portions of ACL adapted at the PCL. In all of these patients we found mechanoreceptors (I and II). In five patients we found mushroomlike remnants which included either none or small numbers of mechanoreceptors. Free neural ends were found in both patient groups. There was a significant difference between the groups in regard to the mean number of mechanoreceptors I and II per slice. In conclusion, in patients with an ACL remnant adapted to the PCL, mechanoreceptors exist even 3 years after injury. If we accept that restoration of proprioception is the result of reinnervation of the ACL, leaving the ACL remnants as a source, if this is surgically possible without risk of Cyclop's lesion, may be of potential benefit to the patient.

Alterations of the extensor apparatus after anterior cruciate ligament reconstruction using the medial third of the patellar tendon.

PURPOSE: The objective of this study was the ultrasound evaluation of the donor defect of the patellar tendon (PT) and the radiologic evaluation of the patella after harvesting of the medial third as a bone-patella tendon-bone (BPTB) graft for anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: This was a cohort study. METHODS: In 45 patients who had ACL reconstruction, the extensor apparatus of the donor side was studied using ultrasound cross-sections and radiographs (anteroposterior, lateral, and a tangential view of the patella) 3 to 70 months postoperatively. Patients were divided into two groups. The early postoperative group (3 to 30 months postoperative) consisted of 27 patients (group A) and the late postoperative group (31 to 70 months postoperative) consisted of 18 patients (group B). The healthy contralateral extensor apparatus was used as control. RESULTS: In group A, the standard ultrasound cross-section area of the PT increased by 20.48%, whereas in group B, it decreased by 4.88%. In group A, the patellar height was decreased by 9.21% in the donor side compared with the control. In group B, the patellar height was decreased by 7.02%. In group A, the Merchant's congruence angle increased by 11.59 degrees, and for group B, this angle increased by 3.82 degrees. This finding indicated that, after the 30th postoperative month, lateral displacement of the patella was not statistically significant (P =.38). In addition, no significant differences were found in the lateral patellofemoral angle in either group. CONCLUSIONS: Our study indicates that the tendon defect is always healed and the final tendon cross-section area is 95% of the contralateral after the 30th postoperative month. In addition, there was a nonsignificant slight lateral displacement of the patella. In contrast, other studies found shown that there is a slight medial displacement of the PT after using the central third as a BPTB graft.

Patellar fractures associated with medial-third bone-patellar tendon-bone autograft ACL reconstruction.

Patella fractures following anterior cruciate ligament (ACL) reconstruction are a recognized but rarely reported complication. To our knowledge, 24 reports of patella fractures after ACL reconstruction using the central-third patella-tendon autograft have been reported in the literature. Patellar fractures associated with the use of the medial-third bone-patellar tendon-bone autograft have not been reported. This article describes four cases of patellar fractures in 478 ACL reconstructions between 1992 and 1999, using the medial third of the patellar tendon graft. All of them were transverse fractures of the patella but only one was displaced. All patients suffered local injury to the donor knee between 2 and 4 months postoperatively. No significant differences in the final outcome were noticed between the cases complicated with patellar fracture and those with uncomplicated ACL reconstructions.

Posterior cruciate ligament architecture: evaluation under microsurgical dissection.

PURPOSE: Our objective was to verify the fiber anatomy of the posterior cruciate ligament (PCL) and to measure the main dimensions and the femoral and tibial attachment site distances of the ligament after microsurgical dissection. We hypothesized that PCL anatomy is more complex than the 2 traditionally characterized bands. TYPE OF STUDY: This is a purely anatomic description of microdissections of the PCL, focused on the fine anatomy of the ligament. MATERIALS AND METHODS: Twenty-four fresh-frozen cadaveric knees were dissected using magnifying loupes and an operative microscope, being careful to avoid creating artificially separated bundles. The main dimensions of the PCL were measured using a micrometer. RESULTS: The anterior, central, posterior-longitudinal, and posterior-oblique were the 4 fiber regions identified based on their orientation and the osseous sites of their insertions. These were partially separable anatomically but were functionally distinct. The anterior and central fiber regions made up the bulk of the ligament, while the remaining 15% consisted of the posterior fiber regions. During manual joint motion, the behavior of these fiber regions was observed. The anterior fiber region appeared to be the most nonisometric and remained in tension mainly between 30 degrees and 90 degrees of flexion. The posterior fiber regions appeared to be the most isometric (especially the posterior-oblique) and remained in tension mainly in extension and partially in deep flexion. The central fiber region appeared to have an intermediate behavior and remained in tension mainly between 30 degrees and 120 degrees of flexion. Additionally, it appeared to be the widest of all fiber regions. CONCLUSIONS: These findings should be of interest and help in interpreting some of the anatomy encountered during arthroscopic examination of the PCL, both from the anterior and posterior lateral portals. Furthermore, this information should prove useful in selecting treatment for the PCL.

Nerve and vessel injuries during high tibial osteotomy combined with distal fibular osteotomy: a clinically relevant anatomic study.

Based on our clinical experience and an anatomical study, we examined the conditions under which injury to the popliteal artery, tibial nerve or peroneal nerve and its branches may occur during high tibial osteotomy. In 250 high tibial osteotomies performed in our department, we observed the following intraoperative complications. (1) The popliteal artery was severed in 1 patient and repaired by the same surgical team using a microsurgical technique. (2) A tibial nerve paresis also occurred in 1 patient. (3) In 3 patients, temporary palsy of the anterior tibialis muscle was documented. (4) In 4 other patients, palsy of the extensor hallucis longus occurred. To investigate the causes of these complications in the popliteal artery, tibial nerve and branches of the peroneal nerve, we dissected the neurovascular structures surrounding the area of the osteotomy in 10 cadaveric knees and performed a high tibial osteotomy in another 13 cadaveric knees. We concluded the following. (1) The popliteal artery and tibial nerve are protected, at the level of the osteotomy, behind the popliteus and tibialis posterior muscles. Damage can occur only by placing the Hohman retractor behind the muscles. The insertion of the muscles is very close to the periosteum and can be separated only with a scalpel. (2) The tibialis anterior muscle is innervated by a group of branches arising from the deep branch of the peroneal nerve. In two-thirds of the dissected knees, we found a main branch close to the periosteum, which can be damaged by dividing the muscle improperly or due to improper placement and pressure of the Hohman retractor. This may explain the partially reversible muscle palsy. (3) The extensor hallucis longus is also innervated by 2-3 thin branches, arising from the deep branch of the peroneal nerve, but in 25% of the specimens, only one large branch was found. This branch is placed under tension by manipulating the distal tibia forward. Thus, it may be damaged by the Hohman retractor during distal screw fixation, tensioned by hyperextension or directly injured during midshaft fibular osteotomy.