The effect of tibial attachment site on graft impingement in an anterior cruciate ligament reconstruction

Arthrofibrosis of the knee in pediatric orthopedic surgery

Arthrofibrosis is a challenging complication associated with knee injuries in both children and adults. While much is known about managing arthrofibrosis in adults, it is necessary to understand its unique aspects and management strategies in the pediatric population. This paper provides an overview of arthrofibrosis in pediatric orthopedic surgery, focusing on its causes, implications, classifications, and management. This paper is a comprehensive review of the literature and existing research on arthrofibrosis in pediatric patients. Arthrofibrosis is characterized by excessive collagen production and adhesions, leading to restricted joint motion and pain. It is associated with an immune response and fibrosis within and around the joint. Arthrofibrosis can result from various knee injuries in pediatric patients, including tibial spine fractures, ACL and PCL injuries, and extra-articular procedures. Technical factors at the time of surgery play a role in the development of motion loss and should be addressed to minimize complications. Preventing arthrofibrosis through early physical therapy is recommended. Non-operative management, including dynamic splinting and serial casting, has shown some benefits. New pharmacologic approaches to lysis of adhesions have shown promise. Surgical interventions, consisting of arthroscopic lysis of adhesions (LOA) and manipulation under anesthesia (MUA), can significantly improve motion and functional outcomes. Arthrofibrosis poses unique challenges in pediatric patients, demanding a nuanced approach that includes prevention, early intervention with non-operative means, and improvements in surgical techniques. Modern pharmacological interventions offer promise for the future. Customized interventions and research focused on pediatric patients are critical for optimal outcomes.

Localized Anterior Arthrofibrosis After Soft-Tissue Quadriceps Tendon Anterior Cruciate Ligament Reconstruction Is More Common in Patients Who Are Female, Undergo Meniscal Repair, and Have Grafts of Larger Diameter

PURPOSE

To determine factors associated with localized anterior arthrofibrosis (cyclops lesion), such as graft size, warranting early reoperation for lysis of adhesions after anterior cruciate ligament reconstruction (ACLR) with all-soft tissue quadriceps tendon (ASTQT) autograft.

METHODS

All primary ASTQT autograft ACLRs within a single surgeon's prospectively collected registry with minimum 6-month follow-up were included. Patients who underwent multiligament knee reconstruction or cartilage restoration procedures were excluded. Localized anterior arthrofibrosis was defined as the requirement for a second procedure to achieve debridement and lysis of adhesions owing to the inability to regain terminal extension within 6 months of ACLR. The sex-specific incidence of arthrofibrosis was evaluated relative to age, weight, femoral and tibial tunnel sizes, meniscal repair, and meniscectomy by a binary logistic regression.

RESULTS

This study included 721 patients (46% female patients). There were 52 cases of localized anterior arthrofibrosis (7.2%). Female patients had a greater incidence of arthrofibrosis than male patients. Male patients with a femoral tunnel diameter of 9.25 mm or greater had an increased incidence of arthrofibrosis compared with those with a diameter of less than 9.25 mm, whereas a similar cutoff was not found to be statistically significant for female patients. Concomitant meniscal repair was associated with an increased risk of arthrofibrosis.

CONCLUSIONS

Female sex and concomitant meniscal repair were associated with an increased localized anterior arthrofibrosis incidence. Furthermore, ASTQT with a femoral tunnel diameter of 9.25 mm or greater in male patients was associated with an increased incidence of arthrofibrosis. LEVEL OF EVIDENCE: Level III, retrospective, comparative prognostic trial.

Predicting the Effect of Localized ACL Damage on Neighbor Ligament Mechanics via Finite Element Modeling

The anterior cruciate ligament (ACL) plays a pivotal role in support of the knee under loading. When damaged, it is known that substantial changes in the mechanics of the neighboring ligaments can be observed. However, a localized damage approach to investigating how ACL deficiency influences the neighboring ligaments has not been carried out. To do this, a finite element model, incorporating a continuum damage material model of the ACL, was implemented. Localized ACL damage was induced using high quadriceps force loading. Once damaged, anterior shear forces or tibial torque loadings were applied to the knee joint. The relative changes in stress contour and average mid-substance stress were examined for each of the neighboring ligaments following localized ACL damage. It was observed that localized ACL damage could produce notable changes in the mechanics of the neighboring knee ligaments, with non-homogenous stress contour shape changes and average stress magnitude being observed to increase in most cases, with a notable exception occurring in the MCL for both loading modes. In addition, the ligament bearing the most loading also changed with ACL deficiency. These changes carry implications as to morphological effects that may be induced following localized ACL damage, indicating that early diagnosis of ACL injury may be helpful in mitigating other complications post injury.

Clinical Management of Arthrofibrosis: State of the Art and Therapeutic Outlook

* Arthrofibrosis is a pathologic condition that is characterized by excessive periarticular scar-tissue formation. Arthrofibrosis may occur secondary to injury, surgical trauma, hemarthrosis, or infection, or it may occur idiopathically.* The pathogenesis of arthrofibrosis is incompletely understood but involves the dysregulation of normal reparative pathways, with transforming growth factor-beta (TGF-[beta]) as a principal mediator.* Current treatment options for arthrofibrosis primarily involve physiotherapy, operative manipulation, and surgical debridement, all with imperfect results.* Currently, there are no pharmacologic treatment options for arthrofibrosis. This has prompted increased investigational interest in the development of antifibrotic intra-articular therapies.

Association of the Graft Size and Arthrofibrosis in Young Patients After Primary Anterior Cruciate Ligament Reconstruction

INTRODUCTION

This study investigated the association of graft-related surgical factors and patient characteristics with the odds of arthrofibrosis after primary anterior cruciate ligament reconstruction (ACL-R).

METHODS

A retrospective case-control study assessed consecutive patients who underwent primary ACL-R in one tertiary pediatric hospital. Each arthrofibrosis case was matched to three controls for sex, calendar year, and age at the time of ACL-R, as well as the primary surgeon. Conditional multivariable logistic regression assessed the independent association of graft diameter, time from injury to ACL-R, concomitant knee pathologies, and body mass index.

RESULTS

Twenty arthrofibrosis cases of 1,121 ACL-R patients (incidence 1.8%) were matched to 60 controls resulting in the mean age of 14.5 years. An increase of 1 mm graft diameter was associated with 3.2-times increased odds of arthrofibrosis. Other variables were not independently associated with arthrofibrosis.

CONCLUSION

For young patients, the decision on the graft size must consider the possibility of arthrofibrosis with a larger graft versus reinjury with a smaller graft.

Clinical Outcomes After Arthroscopic Release of Patellofemoral Arthrofibrosis in Patients With Prior Anterior Cruciate Ligament Reconstruction

PURPOSE

The purpose of this study was to review our results of arthroscopic release in patients diagnosed with refractory patellofemoral arthrofibrosis (PFA) after having undergone anterior cruciate ligament (ACL) reconstruction.

METHODS

From 2006 to 2016, all patients who underwent arthroscopic release for refractory PFA after ACL reconstruction were reviewed retrospectively. All patients then completed surveys containing the International Knee Documentation Committee (IKDC) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and were asked 2 subjective questions. Patients included in the study exhibited at least one finding of PFA and failed conservative treatment for at least 3 months. Included patients also had a minimum of 12 months of postoperative follow-up after PFA release. Patients who underwent any other concomitant surgery in the same operative setting as arthroscopic release for PFA were excluded from the study.

RESULTS

Thirty-two patients were included in the study. The mean age was 32.8 years (range, 19-58 years) with an average follow-up of 43.6 months (range, 16-98 months). There was a statistically significant increase preoperatively to postoperatively in the IKDC score from 49.6 to 69.4 (P < .00001), and 16 of 32 patients (50%) achieved a minimal clinically important difference (MCID). WOMAC scores also significantly increased from 74 to 85.3 (P < .00001), with 15 of 32 patients (47%) achieving MCID. Thirty-one patients (97%) reported that the procedure helped, and 25 patients (78%) said they would have the procedure again.

CONCLUSIONS

Arthroscopic release, consisting of an extended lateral release, debridement of the notch/fat pad, and manual manipulation of the patella, results in significant increases in validated outcome measures and is well tolerated by patients.

LEVEL OF EVIDENCE

Level IV, case series.

Variation in the shape of the tibial insertion site of the anterior cruciate ligament: classification is required

PURPOSE

To propose a classification system for the shape of the tibial insertion site (TIS) of the anterior cruciate ligament (ACL) and to demonstrate the intra- and inter-rater agreement of this system. Due to variation in shape and size, different surgical approaches may be feasible to improve reconstruction of the TIS.

METHODS

One hundred patients with a mean age of 26 ± 11 years were included. The ACL was cut arthroscopically at the base of the tibial insertion site. Arthroscopic images were taken from the lateral and medial portal. Images were de-identified and duplicated. Two blinded observers classified the tibial insertion site according to a classification system.

RESULTS

The tibial insertion site was classified as type I (elliptical) in 51 knees (51 %), type II (triangular) in 33 knees (33 %) and type III (C-shaped) in 16 knees (16 %). There was good agreement between raters when viewing the insertion site from the lateral portal (κ = 0.65) as well as from the medial portal (κ = 0.66). Intra-rater reliability was good to excellent. Agreement in the description of the insertion site between the medial and lateral portals was good for rater 1 and good for rater 2 (κ = 0.74 and 0.77, respectively).

CONCLUSION

There is variation in the shape of the ACL TIS. The classification system is a repeatable and reliable tool to summarize the shape of the TIS using three common patterns. For clinical relevance, different shapes may require different types of reconstruction to ensure proper footprint restoration. Consideration of the individual TIS shape is required to prevent iatrogenic damage of adjacent structures like the menisci.

LEVEL OF EVIDENCE

III.

The influence of graft placement on clinical outcome in anterior cruciate ligament reconstruction

PURPOSE

the aim of the present study was to investigate the influence of graft tunnel position on both clinical outcome and instrumental knee stability in patients submitted to arthroscopic ACL reconstruction using a bone-patellar tendon-bone (BPTB) graft.

METHODS

thirty patients (24 men and 6 women) who underwent ACL reconstruction performed using an autologous bone-patellar tendon-bone graft were studied at a mean follow-up of 18 months. Clinical outcome was assessed on the basis of the Lysholm score, Tegner activity level, International Knee Documentation Committee (IKDC) subjective form and the Short Form-36. Clinical outcomes were correlated with both femoral and tibial tunnel placement measured on standard anteroposterior and lateral knee radiographs, in accordance with established guidelines.

RESULTS

tibial tunnel position on the lateral view correlated significantly with both the IKDC subjective form (r = -0.72; p<0.05) and the Lysholm score (r=-0.73; p<0.05). Tibial tunnel position on the lateral view also correlated with stability measured using a KT-1000 arthrometer at 30N of force (r=0.57; p<0.05). No correlation was found between α angle and anteroposterior (AP) laxity measured by KT-1000 arthrometer. No significant correlation was found between femoral tunnel position (on either view) and Lysholm score, IKDC score and Tegner activity level. Similarly, no correlation was found between AP laxity measured by KT-1000 arthrometer and femoral tunnel position.

CONCLUSIONS

these results suggest that the more anterior the placement of the tibial tunnel, the better the clinical outcome will be. On the basis of literature data and our findings, we discuss the hypothesis that there exists a "correct area" for tunnel placement, making it possible to obtain the best results.

LEVEL OF EVIDENCE

Level IV, case series.

Extension deficit after ACL reconstruction: Is open posterior release a safe and efficient procedure?

BACKGROUND

Extension loss is a potentially devastating consequence of anterior cruciate ligament reconstruction (ACLR). It can often be treated by anterior arthroscopic release. In rare cases, a chronic flexion contracture requires an additional posterior open release. To our knowledge, no study analysing the results of both posteromedial and posterolateral approaches has been performed so far. The purposes of this study were (1) to analyse the midterm outcome and complications of a combined procedure, anterior arthroscopic debridement and posterior open capsulotomy - for the treatment of chronic extension deficits after ACLR and (2) to describe the surgical technique of posterior open release with both posteromedial and posterolateral approaches.

MATERIAL AND METHODS

This is a retrospective clinical cohort study. Twelve patients presenting a chronic flexion contracture of 10° or more after ACLR treated by open posterior arthrolysis with an average follow-up time of 38months (range six to 90) were included. At last follow-up, they underwent both a clinical examination with range of motion analysis, International Knee Documentation Committee (IKDC) and KOOS scores.

RESULTS

At follow-up, all patients except one (93%) achieved complete extension. Only one patient (7%) had a residual post-operative flexion deformity of five degrees. The range of motion (ROM) improved significantly after arthrolysis from 96°±14.3° (SD) to 14.3°±7°(SD)(p<0.001). No post-operative complications were recorded. No patients required further open debridement. The post-operative objective IKDC score was grade A for five patients, B for seven versus C for five patients and D for seven preoperatively. The mean post-operative subjective IKDC score was 86.4±9.7. The post-operative Knee injury and Osteoarthritis Outcome Score (KOOS) distribution was as follows: pain 93.8±5 (SD); symptoms 88±8.6 (SD); ADL 96.8±3.7 (SD); sports activities 83.6±12.3 (SD); and quality of life 82.9±8.8 (SD). Mean patients' satisfaction was 9.25±0.6 (SD) out of 10 after arthrolysis.

CONCLUSIONS

Open posterior release with both posteromedial and posterolateral approaches is a safe and efficient additional procedure in case of persistent flexion contracture after ACLR with good ROM gain, functional scores and patients' satisfaction.

LEVEL OF EVIDENCE

Therapeutic study - Level IV.

Anatomical versus non-anatomical single bundle anterior cruciate ligament reconstruction: a cadaveric study of comparison of knee stability

Background

The purpose of this study was to compare the initial stability of anatomical and non-anatomical single bundle anterior cruciate ligament (ACL) reconstruction and to determine which would better restore intact knee kinematics. Our hypothesis was that the initial stability of anatomical single bundle ACL reconstruction would be superior to that of non-anatomical single bundle ACL reconstruction.

Methods

Anterior tibial translation (ATT) and internal rotation of the tibia were measured with a computer navigation system in seven pairs of fresh-frozen cadaveric knees under two testing conditions (manual maximum anterior force, and a manual maximum anterior force combined with an internal rotational force). Tests were performed at 0, 30, 60, and 90 degrees of flexion with the ACL intact, the ACL transected, and after reconstruction of one side of a pair with either anatomical or non-anatomical single bundle ACL reconstruction.

Results

Under manual maximal anterior force, both reconstruction techniques showed no significant difference of ATT when compared to ACL intact knee state at 30° of knee flexion (p > 0.05). Under the combined anterior and internal rotatory force, non-anatomical single-bundle ACL reconstruction showed significant difference of ATT compared to those in ACL intact group (p < 0.05). In contrast, central anatomical single bundle ACL reconstruction showed no significant difference of ATT compared to those in ACL intact group (p > 0.05). Internal rotation of the tibia showed no significant difference in the ACL intact, the ACL transected, non-anatomical reconstructed and anatomical reconstructed knees.

Conclusions

Anatomical single bundle ACL reconstruction restored the initial stability closer to the native ACL under combined anterior and internal rotational forces when compared to non-anatomical ACL single bundle reconstruction.

Avoiding pitfalls in anatomic ACL reconstruction

As interest in double-bundle anterior cruciate ligament (ACL) reconstruction grows, we continue to refine our technique to perform the most anatomic reconstruction possible. Our experience has brought to our attention the potential mistakes that should be avoided when performing an anatomic double-bundle ACL reconstruction. These mistakes include (1) failure to visualize the femoral insertion completely, (2) use of the clock face to reference femoral tunnel positioning, (3) nonanatomic tunnel placement leading to graft impingement, (4) mismatching tibial and femoral tunnels, and (5) failure to restore the native tension pattern of the ACL. It is also important to recognize that a double-bundle ACL reconstruction is not necessarily equivalent to an anatomic double-bundle reconstruction. This article reviews potential mistakes in DB ACL reconstruction and describes our way of avoiding them.

Transtibial versus anteromedial portal of the femoral tunnel in ACL reconstruction: a cadaveric study

The aim of this cadaveric study was to compare the transtibial versus the anteromedial portal with respect to the anatomic femoral positioning of the ACL attachment. Ten fresh frozen cadaveric knees were included in our study. A standard arthroscopy was performed and the normal ACL was partially cut through with arthroscopic scissors leaving a small footprint of 2 mm at the anatomical insertion area on the lateral femoral condyle. The femoral tunnel was drilled through the tibial tunnel and subsequently through the anteromedial portal. Using a probe with standard magnification, we measured the distances of the two femoral tunnels from the margin of ACL footprint arthroscopically. The femurs were then dissected and we measured the distances of the two tunnels from the posterior part of the lateral femoral condyle. The median arthroscopically measured distance of the centers of transtibial femoral tunnel and of the femoral tunnel through the anteromedial portal from the margin of the femoral ACL footprint were 6.20 mm and 2.80 mm respectively. The difference was statistically significant. After femoral dissection the median distance of the centers of the transtibial femoral tunnel and the femoral tunnel performed through the anteromedial portal from the border of the articular surface at the lateral femoral condyle was 6.10 mm and 5.25 mm respectively (p<0.001). Both measurements showed that ACL reconstruction technique through the anteromedial portal is more accurate compared to the transtibial technique.

Loss of extension following anterior cruciate ligament reconstruction: analysis of incidence and etiology using IKDC criteria

PURPOSE

The purpose of this study was to determine the incidence of and factors associated with loss of extension (LOE) 4 weeks after anterior cruciate ligament (ACL) reconstruction using the new IKDC Knee Ligament Evaluation Form criteria for loss of motion.

METHODS

A retrospective review of patients who had undergone arthroscopic ACL reconstruction between 1995 and 2000 was performed. An endoscopic single tunnel technique with autograft or allograft was used in all cases. A standardized physical therapy program was prescribed to all patients. Subjects with revision ACL reconstruction, concomitant ligament surgery, meniscal transplantation, or any articular cartilage surgery were excluded. LOE was defined as greater than a 5 degrees side-to-side difference in passive knee extension 4 weeks after surgery, the need for repeat arthroscopy to restore extension, or use of a drop-out cast to restore extension.

RESULTS

Fifty-eight of 229 (25.3%) patients developed LOE 4 weeks after ACL reconstruction. LOE was not associated with age, sex, presence of nerve block, concomitant meniscal procedures, specific graft type, or tourniquet time (P > .05). LOE was significantly associated with preoperative extension, time from injury to surgery, and use of autograft (P < .05). Twenty-eight (12.2%) patients underwent an arthroscopic procedure to recover loss of motion. Following arthroscopy, 4 (1.7%) patients had passive motion deficits between 6 degrees and 10 degrees , with none greater than 10 degrees .

CONCLUSIONS

Preoperative range of motion and time to surgery are intimately related to a patient's postoperative extension. While 48% of patients that lacked full extension by 4 weeks eventually required arthroscopic debridement to achieve satisfactory extension, our treatment algorithm led to an overall incidence of LOE greater than 5 degrees at final follow-up of 1.7%.

LEVEL OF EVIDENCE

Level III, therapeutic, retrospective, comparative study.

Arthrofibrosis of the knee

Better understanding of surgical timing, improved surgical technique, and advanced rehabilitation protocols has led to decreased incidence of motion loss after anterior cruciate ligament injury and reconstruction. However, motion loss from high-energy, multiligament injuries continues to compromise functional outcome. Prevention, consisting of control of inflammation and early motion, remains the key element in avoiding motion loss. However, certain techniques, such as manipulation under anesthesia in conjunction with arthroscopic lysis of adhesions, are reliable treatment options. Open surgical débridement is rarely necessary and should be considered only as a salvage procedure. A greater understanding of the pathogenesis of arthrofibrosis and related inflammatory mediators may result in novel therapies for treating the patient with motion loss.

Anterior cruciate ligament reconstruction using navigation: a comparative study on 60 patients

BACKGROUND

Poor outcome in anterior cruciate ligament reconstruction is often related to tunnel position.

HYPOTHESIS

Improving accuracy of the tunnel position will lead to improved outcome.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Sixty patients were randomized to either standard instrumentation or computer-assisted guides to position the tibial and femoral tunnels. The results were evaluated on clinical outcome based on International Knee Documentation Committee form (laxity) and radiologic assessment: radiologic Lachman (Telos at 150 and 200 N) and analysis of the tunnel positions.

RESULTS

International Knee Documentation Committee laxity was level A in 22 knees in the conventional group (mean, 1.5 mm at 200 N) compared with 26 navigated knees (mean laxity, 1.3 mm; P = .49). Laxity was less than 2 mm in 96.7% of the navigated group and 83% of the conventional group (P = .292). The variability of laxity in the navigated group was significantly less than in the conventional group, with the standard deviation of the navigated group being smaller than that in the conventional group (P = .0003 at 150 N and .0005 at 200 N Telos). A significant difference (P = .03) was found between the groups in the ATB value (distance between the projection of the Blumensaat line on the tibial plateau and the anterior edge of the tibial tunnel), characterizing the sagittal position of the tibial tunnel (negative ATB values imply graft impingement in extension). In the conventional group, mean ATB was -0.2 (-5 to +4), whereas it was 0.4 (0 to 3) in the navigated patients. There were no negative ATB values in the navigated group.

CONCLUSION

This study confirms that the accuracy and consistency of tibial tunnel position can be improved by the use of computer-assisted navigation and that the clinical result in terms of laxity is more reliable.

Endoscopic anterior cruciate ligament reconstruction using a computer-assisted fluoroscopic navigation system

BACKGROUND

During anterior cruciate ligament (ACL) reconstruction, placement of the reconstructed ligament affects the clinical results. To accomplish accurate and reproducible placement of the tibial bone tunnel, we employed a fluoroscopic navigation system for endoscopic ACL reconstruction. In this study, preciseness of the tibial tunnel placement was evaluated, and the advantages and disadvantages of this navigation system for endoscopic ACL reconstruction are discussed.

METHODS

Altogether, 16 knees of 16 patients who had undergone ACL reconstruction using this system (navi group) were evaluated regarding the positioning of the tibial tunnel against Blumensaat's line using X-p and the route of the graft by magnetic resonance imaging (MRI). Another 16 knees of 16 patients who underwent endoscopic ACL reconstruction without the navigation system were the controls (control group).

RESULTS

At the 1-year follow-up, maximally extended lateral knee X-p revealed that the anterior edge of the tibial tunnel and Blumensaat's line were almost aligned and that roof impingement was avoided; the T2-weighted MR images showed that the graft was placed close to and parallel to the intercondylar roof in all the knees of the navi group. The ratio of the distance between Blumensaat's line and the anterior edge of the tibial tunnel at the level of the tibial plateau to the anteroposterior width in fully extended true lateral radiographs was 2.7% +/- 3.4% in the navi group and 8.4% +/- 7.4% in the control group.

CONCLUSIONS

The computer-assisted fluoroscopic navigation system improves accuracy and decreases dispersion of the tibial tunnel placement against Blumensaat's line in single-bundle ACL reconstruction. This innovative device renders the reconstruction procedure more reliable, eliminating the problem of skeletal variation among patients. However, the function of this navigation system for femoral tunnel placement is insufficient at present. Further refinement of the system is necessary, and the method of application requires improvement.

Computer-assisted navigation and anterior cruciate ligament reconstruction: accuracy and outcomes

As many as 175,000 anterior cruciate ligament (ACL) reconstructions are performed annually in the United States at a cost >1 billion dollars. Estimates of the rate of revision surgery are as high as 10%-20%, potentially resulting in as many as 35,000 revisions a year. In addition, errors that are not obvious at short-term or mid-term follow-up may have significant long--term effects in young patients. Studies have demonstrated that the majoriity of visions are related to technical errors, primarily tunnel placement. Computer-aided navigation systems provide enhanced precision in tunnel placement and may reduce the rate of revision surgery. Computer-aided systems can provide valuable data on rotational and translational laxity of the knee.

Intraoperative evaluation of the anatomical double-bundle anterior cruciate ligament reconstruction with the OrthoPilot navigation system

The purpose of this study was to assess double-bundle anterior cruciate ligament (ACL) reconstruction, which reproduces the anteromedial bundle and posterolateral bundle, using a navigation system. In 32 patients, anteroposterior (AP) displacement and rotation of the tibia were measured before reconstruction and after posterolateral bundle fixation, anteromedial bundle fixation, and double-bundle ACL reconstruction (in posterolateral and anteromedial bundles fixation). The posterolateral bundle has an important role in the extension position, whereas the anteromedial bundle restricts AP displacement from extension to flexion. AP displacement after double-bundle ACL reconstruction was significantly improved compared to AP displacement after posterolateral bundle or anteromedial bundle fixation. Although traditional reconstruction for reproducing the anteromedial bundle is reasonable, double-bundle ACL reconstruction is recommended for improved knee stability.

Accuracy of anterior cruciate ligament tunnel placement with an active robotic system: a cadaveric study

PURPOSE

The objective of this study was to evaluate the accuracy of tunnel placement for ACL reconstruction performed with an active robotic system.

TYPE OF STUDY

Cadaveric analysis.

METHODS

A reference screw containing 4 fiducials was placed in the femur and tibia of 13 fresh-frozen cadaveric knees. A preoperative plan was developed using images from 3-dimensional computed tomography reconstructions of the knee. The active robotic system then drilled the tunnels. The location and direction of each planned tunnel in the femur and tibia were determined from the preoperative plan. To compare these parameters postoperatively, a mechanical digitizer and a tunnel plug were used. The deviation in location and direction between the planned and drilled tunnel was determined.

RESULTS

In preliminary trials, the tibial tunnel was located inaccurately because slippage of the drill bit occurred on the bone at the start of tunnel drilling. This was minimized by decreasing the feed rate of the robot by 75%. For the remaining 10 knees, deviations with respect to the preoperative plan were found of 2.0 +/- 1.2 mm and 1.1 degrees +/- 0.7 degrees for the intra- articular tibial tunnel location and direction, respectively. For the femur, the deviations were 1.3 +/- 0.9 mm for the tunnel location (intra-articular) and 1.0 degrees +/- 0.6 degrees for the tunnel direction.

CONCLUSIONS

The active robotic system is highly accurate for tunnel placement during ACL reconstruction, meaning that the robot drills the tunnels very close to the surgeon's plan. Comparison to a control group of surgeons could not be made because no preoperative plan is usually created in traditional surgery. However, accuracy values in this study were found to be below the values for precision of repeated tunnel placements reported in the literature.

Anterior cruciate ligament reconstruction the two-incision technique

Historically, the two-incision technique for anterior cruciate ligament (ACL) reconstruction was the standard of practice. It allows predictable, near-anatomic placement of the femoral tunnel and provides highly reproducible results with few complications. There are several major advantages of the two-incision technique over endoscopic methods. These include consistent femoral tunnel placement, elimination of concern for "blowing out the back wall," elimination of the problem of graft-tunnel mismatch, elimination of the problem of screw divergence, and ease of use for revision ACL reconstruction procedures. The angle of the ACL graft is also more anatomic, matching the angle of the native ACL. In this chapter we present our technique for reconstruction of the ACL using the two-incision approach. Indications for its use are discussed. Advantages and disadvantages of the two-incision method compared with the all-endoscopic approach are reviewed.

Graft placement after the anterior cruciate ligament reconstruction: a new method to evaluate the femoral and tibial placements of the graft

In order to evaluate graft placement of the anterior cruciate ligament (ACL) reconstruction and its relationship to the clinical outcome of the patient, 100 patients were examined 7 years after an ACL reconstruction. Clinical assessment was performed using the standard knee ligament evaluation form of the International Knee Documentation Committee (IKDC), and the Lysholm and the Marshall knee scores. We developed a new evaluation method of graft placement after an ACL reconstruction, 'the sum score of the graft placement', which takes into account both the femoral and the tibial positions of the graft simultaneously, and our study showed that 'the sum score of the graft placement' has an association to clinical outcome of patients and that it can better explain the long-term osteoarthritic changes at the injured knee than the separate measurements of the femoral and tibial tunnel placements.

Motion loss after ligament injuries to the knee. Part I: causes

Motion loss continues to be a difficult complication after ligament injury and surgery to the knee. A better understanding of the pathoanatomic causes of motion loss can lead to improved prevention and treatment strategies. When motion loss does occur, early recognition and appropriate treatment can be expected to restore motion and improve function in most patients. Treatment options, although varied, should improve outcome when implemented appropriately. This article is composed of two parts. The first part reviews the current concepts on definitions, incidence, and causes of motion loss. In the second part, to be published later, current strategies on prevention and treatment of motion loss after ligament injury to the knee are reviewed. Emphasis is placed on risk factors and prevention as well as on diagnosis and treatment. The article summarizes the latest information from the basic sciences as well as clinical studies on the problem of motion loss of the knee and attempts to provide a rational approach to these difficult clinical problems.

Graft isometricity in unitunnel anterior cruciate ligament reconstruction: analysis of influential factors using a radiographic model

A radiographic model was developed to investigate the influence of three surgical variables on the change in attachment point distance (CAPD) of a hypothetical graft using the unitunnel technique of anterior cruciate ligament (ACL) reconstruction. Using three different femoral target points, we tested the hypothesis that varying the angle of knee flexion between 70 degrees and 110 degrees and varying the tibial starting point over a 4-cm range do not result in a significant variation in CAPD. We also tested the hypothesis that the CAPD from 0 degrees to 135 degrees is greater than the CAPD from 0 degrees to 90 degrees. There was a statistically significant correlation (r = 0.8465, P < 0.0001) between radiographically estimated and isometer-measured values of CAPD. The tibial starting point and the femoral target point were found to affect the CAPD significantly (P < 0.005). A more proximal tibial starting point was associated with a lower CAPD. Both the center of the anatomic femoral attachment of the ACL, and a point 1 mm medial to the junction of the roof and lateral wall of the femoral intercondylar notch and 6 mm anterior to its posterior margin, were associated with lower CAPD values than a target point 5 mm superior and posterior to the center of the femoral ACL attachment. The angle of knee flexion did not significantly affect the CAPD. The CAPD [0 degrees-135 degrees] was significantly greater than the CAPD [0 degree-90 degrees] for all combinations of variables (P < 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

Passive terminal extension causes anterior tibial translation in some anterior cruciate ligament-deficient knees

The purpose of the present study was to accurately measure anterior tibial translation during passive terminal extension (ATT-PTE) in anterior cruciate ligament (ACL)-deficient knees, and to investigate correlations between various characteristics of such knees and the magnitude of ATT-PTE. The subjects were 79 patients with unilateral ACL-deficient knees and little flexion contracture. All patients were confirmed to have ACL injury of one knee by arthroscopy. Lateral radiographs of the bilateral knees in passive terminal extension were compared, and ATT-PTE was measured using an original superimposition method. The inter-observer and intra-observer reproducibility of measurement was significantly greater for this method than for the method without superimposition. In 42 of the 79 patients (53%), ATT-PTE was greater than 1 mm, while it was greater than 4 mm in 15 patients (19%). ATT-PTE was significantly larger in patients with a large anterior displacement difference (as measured with the KT-1000 arthrometer) (ATT-KT), a long period since injury, a history of reinjury, injury to the meniscus, and the presence of gross pivot shift. On the other hand, ATT-KT was equal to or greater than 2.5 mm in all 79 patients and showed no significant correlation with the time since initial injury, history of reinjury, on injury to the meniscus.

Practical considerations in anterior cruciate ligament replacement surgery

The endoscopic method of anterior cruciate ligament (ACL) reconstruction using a patellar tendon graft that is secured with interference screws is a commonly performed procedure. It has many potential pitfalls, the majority of which are secondary to technical errors. Prevention of errors starts with a full knowledge of normal ACL anatomy and any discrepancies with the size and shape of the graft substitute. Accurate tibial and femoral tunnel placement is essential and involves using consistent intra-articular landmarks and achieving specific radiographic criteria. Accurate tunnel placement minimizes graft excursion and impingement against the roof of the intercondylar notch. This will result in maximum knee stability and motion. Much has been written about the principles of graft-tunnel mismatch and interference screw-bone plug divergence. The clinical implications of these potential sources of error remain somewhat controversial and are discussed in this article.

Sagittal plane imaging parameters for computer-assisted fluoroscopic anterior cruciate ligament reconstruction

Reproducible graft placement in anterior cruciate ligament (ACL) reconstructions is considered to be a critical factor affecting the successful clinical outcome of the procedure. Many current ACL instrument systems rely on intra-articular landmarks to guide the ACL tunnel placement. However, most of these instrument systems use mobile soft tissues as landmarks. We hypothesize that consistently identifiable radiographic contour landmarks can be established that can be used to improve the reproducibility of graft tunnel placement in fluoroscopically and computer-assisted ACL reconstructions. For the tibia, magnetic resonance imaging (MRI) scans showed the average ACL attachment site to be projected at 46% on a line extending from the anterior to the posterior cortices. Intraoperative fluoroscopic images were checked for the reproducibility of this line and its clinical use. For the femur, lateral radiographs demonstrated a consistent relationship between the intercondylar roof line (Blumensaat's line) and the nearly circular profile of the posterior and inferior contour of the lateral femoral condyle. The middle of this circular profile is consistently projected on Blumensaat's line at 66% of its anterior-to-posterior direction. Intraoperative images were used, which showed the aiming drill at the point of entering the lateral femoral condyle. Instead of determining the femoral attachment site relative to Blumensaat's line, we can thus determine its position relative to the center of the circle. Based on intraoperative x-rays, the proposed femoral ACL attachment site can be projected on a line parallel with the Blumensaat's line from the circle center in the posterior direction. Our results indicate that there are consistently identifiable radiographic features on the tibia and femur contours that can be used for fluoroscopic and computer-assisted guidance of ACL graft placement.

Incorporating a statistically based shape model into a system for computer-assisted anterior cruciate ligament surgery

This paper addresses the problem of extrapolating very sparse three-dimensional (3-D) data to obtain a complete surface representation. A new method that uses statistical shape models is proposed and its application to computer-assisted anterior cruciate ligament (ACL) reconstruction is detailed. The rupture of the ACL has become one of the most common knee injuries. One problem during reconstruction is to find the optimal attachment points for the graft. Therefore a system for computer-assisted reconstruction of the ACL has been proposed by TIMC laboratory. During surgery the surgeon collects several data points on the tibial and femoral joint surface with a 3-D localizer system. These 3-D data are used to find those attachment points resulting in a low anisometry of the graft, while preventing impingement between the graft and the femoral notch. As the collected data points only cover a small surface patch of the femur, it is desirable to extrapolate these data to also have a visualization in those areas where no data points are available. A sufficiently good approximation of the actual femur by the model would further allow us to better deal with the notch impingement problem of the graft. The chosen approach is to fit a deformable model to the data points, it can be subdivided into two steps, constructing the model and fitting this model to the data. To incorporate a priori knowledge into the model, the allowed deformations are determined by the statistics of the shape variation of a set of training objects. Matching the training objects together is obtained by elastic registration of surface points using octree splines. The fitting process of the sparse intra-operative data with the statistical model results in a non-linear multi-dimensional function minimization. A hybrid search strategy combining local and global methods is used to avoid local minima. First experimental results with a model generated from 10 femurs are presented, including fitting of the model with both simulated and real intra-operative data.

The appearance of roofplasties on lateral hyperextension radiographs

Graft impingement by the roof of the intercondylar notch has recently been implicated as a cause of failure after anterior cruciate ligament reconstruction. Posterior tibial tunnel placement and roofplasties have been advocated to reduce the incidence of graft-roof impingement. Based on our earlier work in this area, we were concerned that lateral hyperextension radiographs, as advocated by Howell and associates to evaluate impingement, did not accurately reflect the extent of roofplasty accomplished intraoperatively. We hypothesized that these radiographs suggested that the grafts were moderately impinged, when, in fact, they were impingement-free. In a cadaver model, we compared radiographs made before and after roofplasty to determine whether there were any resultant changes in the appearance of the intercondylar roof. We found no detectable difference in 70% (14 of 20) of specimens. A second, subtle line superior to the intercondylar line appeared on radiographs in 30% of the specimens. We concluded that postoperative lateral radiographs may fail to show the effect of a roofplasty and can lead to the overdiagnosis of graft-roof impingement.

The natural history of the intercondylar notch after notchplasty

Ten patients who underwent anterior cruciate ligament reconstruction by one surgeon using autologous patellar tendon grafts were evaluated. A standardized technique of performing a notchplasty was done to remove at least 5 mm of bone at the anterior outlet of the intercondylar notch. Computed tomography scans were done preoperatively, within 1 week postoperatively, and after 1 year of follow-up. There were no statistically significant differences in the measured dimensions of the intercondylar notch between 1 week and 1 year postoperatively. While previous investigations have evaluated the relationship between intercondylar notch dimensions and risk of anterior cruciate ligament injury, we believe this is the first statistical study that addresses the natural history of the intercondylar notch in humans after bone resection. We believe that the data reported here may enhance our understanding and treatment of patients who have undergone previously failed anterior cruciate ligament reconstructions.

Revision anterior cruciate ligament surgery

An increasing number of revision ACL reconstructions are being performed each year. Revision ACL surgery is challenging and cannot be approached in the same manner as primary ACL surgery. Successful revision ACL surgery requires a detailed history, a comprehensive physical examination, appropriate radiologic studies, and careful preoperative planning. The results of revision ACL surgery do not equal the results of primary ACL surgery, and this should be explained to the patient prior to surgery. In order to avoid repeating errors that led to failure of the primary reconstruction, the etiology of the primary failure must be clearly understood before proceeding with the revision procedure. Although graft failure is the most common reason for failure of the original reconstruction and revision surgery, other non-graft-related problems, such as loss of motion, extensor mechanism dysfunction, and degenerative arthritis, can also result in an unsatisfactory outcome and residual complaints. Errors in surgical technique, specifically nonanatomic graft placement and failure to address associated ligamentous injuries at the time of the original procedure, are responsible for graft failures in most reported series. Preoperative planning must address the issues of graft selection, skin incisions, hardware removal, tunnel placement, graft fixation, and associated ligamentous injuries. Loss of motion and in some cases enlarged bone tunnels may require a staged approach. Because of the weaker initial graft fixation, laxity of secondary restraints, the potential need to address associated ligamentous injuries, and the presence of more significant articular cartilage changes, an accelerated rehabilitation program is inappropriate in most revision cases. Successful revision ACL surgery requires a motivated and compliant patient, a well thought out plan, and an experienced surgeon who is knowledgeable and proficient with a variety of different surgical techniques, graft sources, and graft fixation techniques.

Computer assisted reconstruction of the anterior cruciate ligament

Reconstruction of the anterior cruciate ligament is a delicate task for which many different techniques have been proposed. A system consisting of a computer and a three-dimensional optical sensor is proposed to help the surgeon control the placement of a graft. This system can be used to minimize anisometry of the graft and avoid notch impingement. The same system, which had been validated by previous testing on 20 fresh human anatomic specimen knees, was tested on 23 patients who had an anterior cruciate ligament injury. Tunnel placement was performed using the standard technique of Morgan et al and was measured with the computer based system. It was found that all cases had different configurations of tibial and femoral placement. The computer based anisometry measurements ranged from 1.9 mm to 8.8 mm in the anterior part of the graft, and from 1 mm to 13 mm in the centers of the tunnels. Using the computer retrospectively, it was possible to find configurations of the graft in all cases that avoid notch impingement, with anisometry values ranging from 1.3 mm to 3.7 mm. This study shows that a computer based system can be a useful tool for routine anterior cruciate ligament reconstruction and can be useful for research purposes.

Posterior tibial tunnel placement to avoid anterior cruciate ligament graft impingement by the intercondylar roof. An in vitro and in vivo study

Recent recommendations to "customize" tibial tunnel placement based on the slope of the intercondylar roof and the amount knee hyperextension were derived from a series of cases with graft impingement by the intercondylar roof. We believe that this impingement is caused by anterior placement of the graft and not by variations of notch anatomy among individual patients. In Phase 1 of this study, we drilled tibial tunnels in the posteromedial aspect of the anterior cruciate ligament "footprint" after the ligament was excised in cadaveric knees. We then passed an impingement rod into the back of the knee joint. Lateral radiographs with the knee in hyperextension were taken of each specimen, and the distance between the superior border of the rod and intercondylar roof was measured. In Phase 2, we prospectively obtained lateral hyperextension radiographs of 75 consecutive knees with anterior cruciate ligament reconstructions and evaluated them for graft impingement based on recently published guidelines. In Phase 1, we found no cases of impingement and an average roof clearance of 8.3 mm. In Phase 2, we noted no cases of severe impingement, 3 cases of moderate impingement (4%), and 72 cases (96%) with no impingement. We conclude that posteromedial tibial tunnel placement alone is adequate to avoid graft impingement in almost all patients. Individualized tibial tunnel placement with specialized tibial guidance systems is not necessary.

The relationship between anterior cruciate ligament reconstruction tibial tunnel location and the anterior aspect of the posterior cruciate ligament insertion

A retrospective study of arthroscopic anterior cruciate ligament reconstruction in 20 patients was conducted. These patients underwent computed tomography (CT) scans on the involved knee postoperatively to determine sagittal placement of the proximal end of the tibial tunnel (TTp) based on a distance from a specific anatomic reference known as the over-the-back (OTB) ridge. The distance from the posterior aspect of the TTp to the OTB ridge, defined as the backset, was measured from the CT scans. The mean backset was 6.2 mm. The anterior to posterior (AP) tibial plateau diameter was measured from the CT and by plain view radiograph. The mean AP diameter by CT scan was 55.1 mm and the mean AP diameter by radiograph was 55.4 mm. A Pearson correlation coefficient of r = .633 comparing backset versus AP diameter suggests a moderately significant positive relationship. For the AP diameter comparing measurement method, CT versus radiograph, r = .985, representing a highly significant positive relationship, confirming AP diameter sizing accuracy by inexpensive radiography versus CT scan. A proposed backset model based on these data uses three fixed distances, derived by ratio, within a 2-mm range. This model is defined by 5-, 6-, and 7-mm backset intervals for < 50 mm, 50 to 60 mm, and > 60 mm AP diameters respectively, and is currently under prospective clinical investigation.

The relationship between tunnel placement and clinical results after anterior cruciate ligament reconstruction

To correlate clinical results after anterior cruciate ligament reconstruction with tunnel placement measured radiographically, we prospectively studied 128 patients who had arthroscopically assisted bone-patellar tendon-bone reconstructions. Patients with bilateral anterior cruciate ligament reconstructions, other significant knee ligament injuries, or those undergoing chondroplasty or meniscal repairs were excluded, leaving 42 patients. The relationship between radiographic tunnel position and clinical results was determined using the Lysholm score, KT-1000 arthrometer testing, the Tegner activity level, and the pivot shift and Lachman tests. Clinical results correlated positively with posterior femoral tunnel placement on lateral radiographs and negatively with excessive anterior tibial tunnel placement. Specifically, when femoral tunnels were placed at least 60% posterior along Blumensaat's line and tibial tunnels were at least 20% posterior along the tibial plateau, 69% of patients had good or excellent Lysholm scores and 79% had KT-1000 arthrometer maximum manual side-to-side differences of 3 mm or less. When the above criteria were not met, 50% of patients had good or excellent Lysholm scores and 22% had KT-1000 arthrometer maximum manual side-to-side differences of 3 mm or less. This close correlation indicates that satisfactory radiographic tunnel position influences outcome after anterior cruciate ligament reconstruction.

Arthroscopic arthrolysis for flexion contracture following intraarticular reconstruction of the anterior cruciate ligament

This article describes the surgical technique and expected results for arthroscopic arthrolysis for the treatment of flexion contracture following anterior cruciate ligament (ACL) reconstruction. The technique emphasizes a systematic approach to the surgical procedure followed by an intensive rehabilitation program. The results in 11 patients treated with this technique are reviewed. They averaged 12.6 months from the index ACL reconstruction. Despite extensive physical therapy, their mean preoperative flexion contracture was 19 degrees, mean total range of motion was 94 degrees, and mean preoperative Lysholm score was 67. At a mean follow-up of 22 months following arthrolysis and physical therapy, mean flexion contracture improved to 2 degrees, total range of motion improved to 125 degrees, and mean Lysholm score improved to 94.

Failure of anterior cruciate ligament reconstruction: the biologic basis

The replacement tissue used for anterior cruciate ligament reconstruction undergoes extensive biologic remodeling and incorporation after implantation. Successful biologic incorporation of the graft is dependent on a number of factors including graft placement, tensioning, and the nature of the tissue (allograft versus autograft). Failure of an anterior cruciate ligament reconstruction may occur on the basis of either technical, mechanical, or biological factors. Biologic factors include cellular repopulation, matrix remodeling, the ultimate small diameter collagen fibril orientation, the final cross sectional area of the graft, a favorable vascularization, and not overloading the graft during the remodeling process. The fully incorporated graft never duplicates the native anterior cruciate ligament but works as a check reign that makes the knee more functional.

The "N + 7 rule" for tibial tunnel placement in endoscopic anterior cruciate ligament reconstruction

Tibial tunnel placement during endoscopic anterior cruciate ligament (ACL) reconstruction has received increased emphasis in the recent literature. Appropriate tunnel length is a critical technical consideration. A tunnel that is too short results in graft extrusion, necessitating supplemental fixation techniques. A tunnel that is too long may make distal fixation and femoral tunnel placement difficult. A simple rule is proposed that allows for correct tunnel length and allows placement of the bone plug consistently within the tibial tunnel, allowing interference screw fixation.

Radiographic evaluation of native anterior cruciate ligament attachments and graft placement for reconstruction. A cadaveric study

We examined seven cadaveric knees to determine the radiographic location of the native anterior cruciate ligament insertion sites as well as the location of tunnels used in anterior cruciate ligament reconstruction. Posteroanterior and lateral views at several flexion angles were taken with radiopaque markers around the insertions of the native anterior cruciate ligament and subsequent reconstruction tunnels. The femoral insertion was best seen on the 60 degrees notch view. On the lateral view, the femoral tunnel was easily seen as it crossed the roof of the intercondylar notch; however, because of the angle of the tunnel, the actual entrance into the knee may be well distal and anterior to this location. The tibial insertion and tunnel were easily seen at any flexion angle. The center of the insertion was 40% of the tibial diameter from the anterior margin. The lateral view in extension allowed determination of the tibial tunnel's location in relation to the intercondylar notch roof, but by itself did not allow accurate determination of the femoral tunnel's position. Notch and extension lateral radiographs together provided sufficient information for evaluation of anterior cruciate ligament graft position in a convenient, cost-effective format. Neither view by itself provides enough information to evaluate the position of the graft.

Radiological method for preoperative determination of isometric attachment points of an anterior cruciate ligament graft

The purpose of this study was to develop a radiological method which would be preoperatively available to help determine the best graft placement (with respect to isometricity as well as absence of graft impingement) for all knees. The radiological method is described in full detail. We also present the most significant experimental work supporting our development. Firstly, we studied the path followed by radio-opaque objects inserted in the mobile tibia around the fixed femur. Secondly, we compared the distances measured between selected femoral and tibial points radiologically (according to our method) and clinically (with a currently available isometer). The main results were: (1) every tibial point considered moves on an arc of a circle centered or a corresponding femoral point. We should then speak of pairs of isometric points instead of a single femoral isometric zone; (2) the more posterior the tibial point, the more anterior and distal the corresponding femoral point and vice versa; (3) the distance variations induced by rotation did not exceed 1.5 to 2.5 mm when measured either radiologically or clinically; (4) on the radiological and clinical measurements, the difference of length variations during flexion was also very small (mean 0.22 mm; SD 1.2 mm). We conclude that this very simple method allows us to find the femoral transition line for every knee (whatever its size, shape or dynamics). It aids preoperative planning in anterior cruciate ligament graft reconstruction.

[Complications in 283 cruciate ligament replacement operations with free patellar tendon transplantation. Modification by surgical technique and surgery timing]

In our retrospective study we reviewed 283 patients who were operated on between 1984 and 1993 after an ACL-rupture. We used a free patellar tendon bone graft in all patients. The aim was to assess the complications such as infections, thrombosis, limitation of movement and graft failures. We also looked on the timing of operation and the technique. We saw an overall complication rate of 21.6%. The most common complication was a restricted range of motion in 10.9% which required surgery. In patients treated immediately after injury (within 7 days) we found an arthrofibrosis rate of 17.6%. In delayed surgery (more than 4 weeks after injury) this complication was only seen in 6.1%. The rate of infection was 4.6%, the rate of thrombosis 1.8% and in 4,2% we had to accept an ongoing instability. With these findings we now evaluate the needs and the social environment even more closely to find the best treatment protocol for each individual. In conclusion we favour secondary ACL-reconstruction.

Knee extension and its relationship to the slope of the intercondylar roof. Implications for positioning the tibial tunnel in anterior cruciate ligament reconstructions

This study determined that knee extension (range, -30 degrees to 2 degrees) and the slope of the intercondylar roof (range, 26 degrees to 46 degrees) vary widely between knees in both men and women. We found a weak relationship between knee extension and the slope of the intercondylar roof (r2 = 0.207); therefore, roof angle cannot be predicted by clinically measuring knee extension. CLINICAL RELEVANCE; A knee with a given degree of extension can have a variety of different slopes to the intercondylar roof. Knees with the combination of hyperextension and a vertically oriented slope to the intercondylar roof are "unforgiving" because they require a more posterior position for the tibial tunnel to avoid roof impingement and an extensive roofplasty. If the surgical objective is to minimize the extent of the roofplasty and avoid roof impingement, then consideration should be given to customizing the placement of the tibial tunnel to account for variability in knee extension and roof angle when reconstructing the anterior cruciate ligament. Studies have shown that isometric graft placement can be achieved with this surgical approach.

The intercondylar fossa of the normal canine stifle an anatomic and radiographic study

The intercondylar fossa (ICF) in dogs consists of a cranial outlet, intercondylar shelf, caudal arch, caudal outlet, a medial wall, and a lateral wall. The normal cranial outlet is bell-shape and, in mixed-breed dogs (mean body weight 19.2 kg, N = 21), measured 5.8 mm cranially, 8.1 mm centrally, and 10.3 mm caudally. The ICF is oriented 12 degrees from the dorsal plane of the femoral diaphysis and obliqued 7 degrees, proximolateral to distomedial, in the sagittal plane. To adjust for dog size, a fossa width index (FWI) was calculated by dividing the cranial outlet width by the distance between epicondyles. The normal FWI as determined in this study was 0.18 cranially, 0.25 centrally, and 0.32 caudally. The fossa height index 0.31. Contact between the ICF and the cranial cruciate ligament began at about 115 degrees of extension. The contact area moved cranially in the intercondylar fossa as the stifle was extended. Evaluation of the ICF can be performed radiographically but positioning is critical.

The effect of intercondylar notchplasty on the normal canine stifle

This study evaluated the effect of notchplasty (enlargement of the intercondylar fossa) in stable and unstable canine stifles. Bilateral notchplasty and unilateral cranial cruciate ligament (CrCL) transection were performed in 6 dogs. Exercise, consisting of walking 1.5 miles three times a week, began 1 month after surgery and continued until euthanasia 6 months after surgery. Evaluation methods included orthopedic examination, serial radiographs, thin section radiography, histopathology, and gross pathology. Notchplasty in the stable stifle did not cause lameness beyond 3 weeks, joint instability, or degenerative joint disease. In the stable stifle, smooth resurfacing of the notchplasty site with fibrous and osseous tissue occurred. Stifles with notchplasty and CrCL transection exhibited persistent lameness, instability, and degenerative joint disease. In CrCL deficient stifles osteophytes formed within the notchplasty site, resulting in a rough surface. Our observations indicated significant refilling in notchplasties of both stable and unstable stifles (P < .05). However, the intercondylar fossa (ICF) width 6 months after notchplasty was significantly smaller in unstable stifles compared with stable stifles (P < .05) indicating that greater refilling of the notchplasties occurred in the unstable stifles. In clinical cases, notchplasty should be larger than the desired final result to accomodate the partial refilling that occurs even in stable stifles.