Mini-open vs. arthroscopic double tight-rope reconstruction after acute AC-joint dislocation: a comparison in functional outcome and sports activity.

INTRODUCTION: In athletes, acromioclavicular joint disruptions account for up to 50% of all shoulder injuries. In high-grade injuries, surgery is favored to ensure a correct restoration of the joint, especially in young athletes. The aim of this study was to compare the clinical, radiological and sport related outcomes of the arthroscopic stabilization with the fixation of the AC joint in a mini-open approach. MATERIALS AND METHODS: 19 patients treated arthroscopically (ASK) and 26 patients with an acute AC-joint dislocation Rockwood V who had undergone the mini-open (MO) surgery were included. Constant Murley Score (CMS), Taft Score (TS) and the Simple Shoulder Tests (SST) were evaluated. The sports activity level was determined according to Valderrabano and the athlete's recovery of their athletic activity level after surgery according to Rhee. Furthermore, all available X-ray images were analyzed. RESULTS: Patients in the ASK group achieved an average score of 11.7 ± 0.6 points in the SST, 10.3 ± 1.8 points in the TS and 91.2 ± 11.8 points in the CMS. On average, patients in the MO group achieved results of 10.5 ± 1.4 points in the SST, 11.7 ± 0.7 points in the TS and 91.6 ± 9.8 points in the CMS. The ASK group showed significant difference regarding the CC distance in side comparison (Δ = 3.6 mm), whereas no significant difference was found in the MO group (Δ = 0.8 mm). In comparison of both groups, the posterior as well as the combined translation were significantly greater in the ASK group than in the MO group (posterior: ASK: 24.8 mm, MO: 19.3 mm, combined: ASK: 29.1 mm, MO: 20.9 mm). Residual horizontal instability was greater in the ASK group (43%) than in the MO group (32%). Similar results were achieved in sports activity and the recovery of athletic activity (Valderrabano: ASK: 2.8, MO: 2.6; Rhee: ASK: 1.6, MO: 1.5). CONCLUSIONS: Both techniques prove to be effective for the stabilization of high-grade AC-joint disruptions in athletes and showed excellent clinical results. From a radiographic standpoint, the mini-open procedure appears superior to the arthroscopic technique. After mini-open surgery postoperative loss of correction is less common and greater horizontal stability is achieved. The results also suggest the mini-open technique is superior to the arthroscopic procedure when aiming to restore the athlete's original level of sports activity.

[Revision of anatomic shoulder arthroplasty]. / Revision der anatomischen Schulterprothese.

With the increasing number of primary arthroplasties, revisions of anatomical prostheses are becoming increasingly important. The most common reasons for revision are glenoid loosening, including protrusion, rotator cuff insufficiency, including instability, and early/late infection. The reconstruction of glenoid defects can be done with an autograft or allograft. Depending on the size and situation, it is carried out in one or two stages. The stemless humeral head replacement and the short-stem prostheses that have been used more frequently in recent years have significantly simplified humeral revision. Platform systems take a different approach with the option of conversion without major interventions on the glenoid or revision stem. Intraoperative complications mainly occur on the humeral side. Postoperative complications include dislocation, component loosening, and infection. Revision of anatomical to reverse arthroplasty shows better clinical outcomes and lower complication rates than anatomical revision.

Fourteen years of follow-up after first arthroscopic Bankart repair in athletes: functional outcomes and magnetic resonance imaging findings.

BACKGROUND: The arthroscopic Bankart procedure is the most performed surgery for shoulder stabilization. Short-term to midterm results are well studied; however, long-term results over 10 years are rare. PURPOSE: This study evaluates the long-term results and magnetic resonance imaging (MRI) findings in athletes at a mean follow-up of 14 years after an arthroscopic Bankart stabilization as well as risk factors for osteoarthritis. METHODS: A total of 63 athletes had an arthroscopic Bankart repair between 2001 and 2008, of whom 46 patients (73.0%) participated in the final follow-up. The Constant, Rowe, and Western Ontario Shoulder Instability Index (WOSI) score and the rate of return to sports were evaluated. Glenohumeral osteoarthritis was assessed using the Samilson-Prieto classification. Known risk factors for osteoarthritis were analyzed. MRI findings (bone marrow edema, cysts, and joint effusion) were analyzed. RESULTS: The average follow-up was 14 years. Assessment was performed on 46 athletes with an average age of 21.6 at the time of surgery. The overall redislocation rate was 21.7%. The Constant score was 96.7, the Rowe score was 83.4, and the Western Ontario Shoulder Instability Index score was 90.7 out of 100. A total of 84.8% of the athletes returned to their initial sports level. Glenohumeral osteoarthritis occurred in 28.1%. Known risk factors for osteoarthritis were confirmed. Further MRI findings were rare. CONCLUSIONS: Arthroscopic Bankart repair in athletes shows good long-term clinical results. However, this is only in patients without osteoarthritis, which was rare, but was confirmed as a risk factor. We assume that resorption of anchors differs in patients. If it does have an impact on developing arthrosis, this should be confirmed in further studies.

Analysis of revision shoulder arthroplasty in the German nationwide registry from 2014 to 2018.

BACKGROUND: The purpose of this study is to identify and analyze primary revision arthroplasties of the shoulder in the Germany Shoulder Arthroplasty Registry. The objective is to provide demographic and clinical data of the included cases and information about the revision surgery itself and to compare the findings to other registry studies and clinical studies. METHODS: All documented cases of primary revision arthroplasties of the Germany Shoulder Arthroplasty Registry in the time period 2014-2018 (n = 975) were included in the initial data analysis. Exclusion criteria were multiple revisions and data sets with a missing link of the revision arthroplasty to the data set of the primary implantation leaving n = 433 cases that were included. SPSS software (IBM SPSS Statistics for Windows, version 24.0; IBM Corp., Armonk, NY, USA) was used for statistical analyses. RESULTS: The age of patients with revised anatomic implants (66.3 years) was significantly lower than that of patients with reverse implants (77.1 years) (P = .001). Female patients with anatomic and fracture implants were significantly older than their male counterparts (70.1 vs. 60.5 years, P = .001; 74.3 vs. 62 years, P = .019) and showed a significantly higher rate of revision than their male counterparts (P = .001). The reason for revision was significantly different for anatomic and reverse implant systems (P = .001). Aseptic loosening of either the humeral or glenoid component was the most common reason for revision for anatomic implants, whereas unspecified reasons, dislocation, and loosening of the glenosphere were the most common reasons for reverse implants. The most common type of revision procedure for anatomic implants was conversion to a reverse system in about one third of the cases. Most of the revisions of reverse implants were not specified and almost equally distributed for revision at the humeral or the glenoid side. Anatomic implants showed significantly better Constant-Murley scores (26.1 points) than reverse implants (19.6 points) (P = .001) and significantly better function before revision for passive flexion (P = .002), passive abduction (P = .015), active external rotation (P = .002), and passive external rotation (P = .002). CONCLUSION: This study provides a well-documented basis to compare revision arthroplasties of the shoulder performed in Germany over the last decade as documented in the nationwide registry with other nationwide registries and with clinical studies. Especially, the detailed analysis of intraoperative and postoperative complications and the shoulder function at the time of revision offers new information in addition to the results of other registries.

Clinical and radiologic results after anatomic stemless shoulder prosthesis: a minimum 4-year follow-up.

BACKGROUND: Since the introduction of stemless anatomic shoulder arthroplasty, few midterm functional and radiographic results have been published. This article presents results of the Arthrex Eclipse prosthesis with a mean follow-up of 70 months. METHODS: We prospectively evaluated the outcome of 53 arthroplasties in 51 patients with a mean age of 65 years at the time of implantation with a minimum follow-up of 48 months. All patients were physically and radiologically examined, and the results documented by Constant-Murley and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. RESULTS: Significant improvements from preoperative to last follow-up were documented in the Constant-Murley score (53.8%-83.5%, P < .001) and active range of motion (abduction 84°-108°, flexion 98°-125°, and external rotation 19°-41°). There was no significant difference between total and hemiarthroplasty. The mean DASH score was 28.3 points (95% confidence interval 20.1-35.2). Lowering of bone mineral density was observed in anteroposterior radiographs at the humeral component in 24.5% and at the glenoid component in 33.3%. The rate of complications was 15.7%. CONCLUSION: This study finds improvements in functional, radiographic, and subjective midterm results comparable to other accessible data for stemless and stemmed arthroplasty.

Immobilization in External Rotation and Abduction Versus Arthroscopic Stabilization After First-Time Anterior Shoulder Dislocation: A Multicenter Randomized Controlled Trial.

BACKGROUND: Treatment of first-time shoulder dislocation (FSD) is a topic of debate. After high rates of recurrent instability after nonoperative management were reported in the literature, primary repair of FSD significantly increased. At the same time, new concepts were proposed that had promising results for immobilization in external rotation (ER) and abduction (ABD). PURPOSE: The aim of this study was to evaluate the recurrence rates (primary outcome) and clinical outcomes (secondary outcome parameters) of immobilization in ER+ABD versus arthroscopic primary stabilization after FSD. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: In a multicenter randomized controlled trial, patients with FSD were randomized to either treatment with immobilization in 60° of ER plus 30° of ABD (group 1) or surgical treatment with arthroscopic Bankart repair (group 2). Clinical evaluation was performed 1, 3, and 6 weeks as well as 6, 12, and 24 months postoperatively or after reduction, including range of motion, instability testing, subjective shoulder value, Constant-Murley score, Rowe score, and Western Ontario Shoulder Instability Index. Recurrent instability events were prospectively recorded. RESULTS: Between 2011 and 2017, a total of 112 patients were included in this study. Of these, 60 patients were allocated to group 1 and 52 to group 2. At the 24-month follow-up, 91 patients (81.3%) were available for clinical examination. The recurrence rate was 19.1% in group 1 and 2.3% in group 2 (P = .016). No significant differences were found between groups regarding clinical shoulder scores (P > .05). Due to noncompliance with the immobilization treatment protocol, 4 patients (6.7%) were excluded. CONCLUSION: Immobilization in ER+ABD versus primary arthroscopic shoulder stabilization for the treatment of FSD showed no differences in clinical shoulder scores. However, recurrent instability was significantly higher after nonoperative treatment.

Traumatic medial clavicle fracture induced by chin bar of a full-face helmet following a downhill mountainbike accident.

Downhill mountain biking is a rapidly growing sport. In our case we want to present an isolated medial clavicular fracture following a mountain bike accident with a critical review on the used protection device. A 35 year old healthy patient presented to our hospital after bike accident during downhill mountain biking in Austria with pain over his right medial clavicle. The imaging showed a multifragmentary medial clavicle fracture with an intact SC-joint. Surgical intervention was recommended. Postoperative x-rays showed an anatomic reposition and correct plate positioning. The implant was removed after 18 months without any complications. A full-face helmet with a chin bar is used to achieve better protection of the maxilla, mandible and the teeth. In a hyperflexion situation of the cervical spine, a direct contact of the chin bar with the sternum, sc-joint and the medial clavicle can occur. This impact sets the mentioned structures on a high risk of dislocation and fracture as seen in our case. This risk can be significantly reduced by the combined use of a full face helmet and a neck brace. If the injury is properly identified, positive results can be achieved by surgery.

Rehabilitation following rotator cuff repair: A work of the Commission Rehabilitation of the German Society of Shoulder and Elbow Surgery e. V. (DVSE) in collaboration with the German Association for Physiotherapy (ZVK) e. V., the Association Physical Therapy, Association for Physical Professions (VPT) e. V. and the Section Rehabilitation-Physical Therapy of the German Society for Orthopaedics and Trauma e. V. (DGOU).

BACKGROUND: Tears and lesions of the rotator cuff are a frequent cause of shoulder pain and disability. Surgical repair of the rotator cuff is a valuable procedure to improve shoulder function and decrease pain. However, there is no consensus concerning the rehabilitation protocol following surgery. OBJECTIVES: To review and evaluate current rehabilitation contents and protocols after rotator cuff repair by reviewing the existing scientific literature and providing an overview of the clinical practice of selected German Society of Shoulder and Elbow Surgery e. V. (DVSE) shoulder experts. MATERIALS AND METHODS: A literature search for the years 2004-2014 was conducted in relevant databases and bibliographies including the Guidelines International Network, National Guidelines, PubMed, Cochrane CentralRegister of Controlled Trials, Cochrane Database of Systematic Reviews, and the Physiotherapy Evidence Database. In addition, 63 DVSE experts were contacted via online questionnaire. RESULTS: A total of 17 studies, four reviews and one guideline fulfilled the inclusion criteria. Based on these results and the obtained expert opinions, a four-phase rehabilitation protocol could be developed.

Magnetic resonance imaging in evaluation of tunnel diameters prior to revision ACL reconstruction: a comparison to computed tomography.

OBJECTIVE: Revision ACL reconstruction is becoming more frequent because of a 10% rate of re-ruptures and insufficiencies. Currently, computed tomography (CT) represents the gold standard in detecting and measuring the tunnels of the initial ACL reconstruction. The purpose of this study was to compare measurement results of CT and thin-sliced MRI sequences, which were modified to a high soft tissue-bone contrast. MATERIALS AND METHODS: Prior to an ACL revision surgery, 16 consecutive patients had an MRI in addition to the standard CT scan. A dedicated 0.25-T Esaote G-Scan (Esaote Biomedica, Cologne, Germany) with a Turbo 3D T1 sequence was used for MRI. Tunnel diameters were measured at 11 defined points of interest. For the statistical evaluation, the Mann-Whitney U test for connected samples was used. Inter- and intraobserver reliability was additionally calculated. RESULTS: All measured diameters showed significant to highly significant correlations between both diagnostic tools (r = 0.7-0.98). In addition, there was no significant difference (p > 0.5) between the two techniques. Almost all diameters showed nearly perfect intraobserver reliability (ICC 0.8-0.97). Interobserver reliability showed an ICC of 0.91/0.92 for only one diameter in MRI and CT. CONCLUSION: Prior to ACL revision surgery, bone tunnel measurements can be done using a 3D T1-MRI sequence in low-field MRI. MRI measurements show the same accuracy as CT scans. Preoperative radiation exposure in mainly young patients could be reduced. Also the costs of an additional CT scan could be saved.

Partially loaded plain radiographic measurement to evaluate rotational alignment in total knee arthroplasty.

PURPOSE: Rotational alignment of prosthetic components after total knee arthroplasty (TKA) is predominantly monitored with computer tomography (CT), for example by relating the anatomical transepicondylar axis (a-TEA) of the native femur to the posterior bicondylar axis of the prosthetic component (PBCA). The purpose of the present study was to portray a reliable, novel plain radiographic method that likewise enables the evaluation of rotational positioning of prosthetic components in TKA. Furthermore, it was intended to evaluate the prosthetic femoro-tibial functional behavior under loaded conditions. METHODS: Modified plain axial radiographs under partial weight bearing (20 kg) were performed in 63 patients (63 knees) after TKA. On the obtained radiographs, all established, relevant anatomic, and prosthetic axis and angles reflecting the rotational position of the femoral (i.e., a-TEA/PBCA angle) and tibial component were detected twice by two independent examiners with an interval of one month. Additionally, in 14 cases with anterior knee pain after surgery, radiographic results were compared to obtained computer tomography images; intraclass coefficients (ICC's) for intra- and inter-rater reliability were calculated. RESULTS: All pre-assigned axis and angles could be identified doubtlessly by both examiners in all investigated knees. For all measurements, ICC's for intra-rater and inter-rater reliability ranged from 0.75 to 0.96. The comparison of the radiographic measurements with corresponding CT results (n = 14) revealed no significant differences (p > 0.05). Rotational alignment of the tibial tray in relation to the native tibial bone was not measurable due to display overlaying. Femoro-tibial behaviour of the prosthetic components under partial loading showed a high variability. CONCLUSION: We were able to establish a new reliable radiographic technique that is able to show the most established and relevant anatomic landmarks and prosthetic axis after TKA to assess the rotational alignment of the prosthetic components in TKA in relation to the distal femur. The evaluation of the femoro-tibal behaviour instead shows a high variability and so far does not allow valid explanatory conclusions.

Preventive lateral ligament tester (PLLT): a novel method to evaluate mechanical properties of lateral ankle joint ligaments in the intact ankle.

PURPOSE: To construct and evaluate an ankle arthrometer that registers inversion joint deflection at standardized inversion loads and that, moreover, allows conclusions about the mechanical strain of intact ankle joint ligaments at these loads. METHODS: Twelve healthy ankles and 12 lower limb cadaver specimens were tested in a self-developed measuring device monitoring passive ankle inversion movement (Inv-ROM) at standardized application of inversion loads of 5, 10 and 15 N. To adjust in vivo and in vitro conditions, the muscular inactivity of the evertor muscles was assured by EMG in vivo. Preliminary, test-retest and trial-to-trial reliabilities were tested in vivo. To detect lateral ligament strain, the cadaveric calcaneofibular ligament was instrumented with a buckle transducer. After post-test harvesting of the ligament with its bony attachments, previously obtained resistance strain gauge results were then transferred to tensile loads, mounting the specimens with their buckle transducers into a hydraulic material testing machine. RESULTS: ICC reliability considering the Inv-ROM and torsional stiffness varied between 0.80 and 0.90. Inv-ROM ranged from 15.3° (±7.3°) at 5 N to 28.3° (±7.6) at 15 N. The different tests revealed a CFL tensile load of 31.9 (±14.0) N at 5 N, 51.0 (±15.8) at 10 N and 75.4 (±21.3) N at 15 N inversion load. CONCLUSIONS: A highly reliable arthrometer was constructed allowing not only the accurate detection of passive joint deflections at standardized inversion loads but also reveals some objective conclusions of the intact CFL properties in correlation with the individual inversion deflections. The detection of individual joint deflections at predefined loads in correlation with the knowledge of tensile ligament loads in the future could enable more individual preventive measures, e.g., in high-level athletes.

Systematic diagnosis and therapy of lateral elbow pain with emphasis on elbow instability.

PURPOSE: In recalcitrant epicondylitis innumerable operative techniques have been published, nevertheless a certain percentage of patients remains symptomatic after operative treatment. We developed an individual, systematic diagnostic pathway including arthroscopic assessment of elbow stability to identify the optimal and respectively less invasive therapy. METHODS: We so far included 40 patients with recalcitrant lateral epicondylitis (mean age 46 ± 11). 5 patients had previous surgery. In all patients, we did an elbow arthroscopy and a systematic arthroscopic stability testing. 25 patients were treated exclusively arthroscopically once instability was excluded. In 13 patients with slight instability, we did an open debridement of the lateral tendon complex and local refixation. Two patients with severe instability were treated with open debridement and additional stabilization of the LUCL with a trizeps graft. With a minimum follow-up of 1 year, we assessed the DASH score and subjective patient satisfaction. RESULTS: Mean follow-up was 24 ± 12 months, mean duration of symptoms before surgery was 19 ± 18 months. The mean DASH score at follow-up was 22 ± 19.36 patients reported symptoms improvement, 34 patients would repeat surgery given the same situation; in 30 cases, patients expectations had been fulfilled. We did not observe any intraoperative complications or infections. One patient developed joint stiffness requiring reoperation. CONCLUSION: Using a systematic diagnostic pathway including assessment of elbow stability and consecutive individualized, respectively, less invasive surgical procedure we acquired high patients satisfaction and good clinical outcome with a low complication rate. LEVEL OF EVIDENCE: Level III.

The TT-TG Index: a new knee size adjusted measure method to determine the TT-TG distance.

PURPOSE: Medial transfer of the tibial tubercle has become a standard procedure in cases of patella instability caused by an increased tuberositas tibae-trochlear groove (TT-TG) distance. However, the TT-TG distance has always been assessed as an absolute value without taking individual joint size into consideration. It was assumed that the pathological influence of the TT-TG distance correlates with individual joint size. Aim of the current study therefore was to develop a method to express TT-TG distance in relation to these joint variables. METHODS: Two hundred knee MRI scans of healthy individuals (69 females and 131 males) were evaluated retrospectively in a control group. First, the TT-TG distance was measured as described by Schoettle et al. To determine joint size, the proximal-distal distance between the entrance of the chondral trochlear groove (TE) and the onset of the patella tendon at the tibial tubercle (TT) was selected. Subsequently, the TT-TG/TT-TE ratio expresses the relationship between the TT-TG distance and the proximal-distal distance from the entrance of the chondral trochlear groove to the height of the tibial tubercle. The TT-TG Index can also be expressed as an angle (TT-TG angle). Likewise, in another patient group, 54 knee MRTs of patients with patellofemoral instability were evaluated. RESULTS: The average TT-TG distance of the control group was 7.5±3.5 mm (range 0-17.4 mm) with no significant differences between genders. The mean TT-TE distance was 63.9 mm (range 49-79 mm) with there being significant differences between genders. The resulting mean TT-TG Index was 0.12±0.05 (range 0-0.25). In the patient group, the average TT-TG distance was 13.5±4.1 mm and the average TT-TE distance was 61.3±6.8 mm. The resulting average TT-TG Index of 0.22±0.07 in the patient group (PFI) approximates the threshold determined by the 95% confidence interval in the healthy control group. A direct comparison between the control group and the patient group revealed a significant difference in the TT-TG distance (p=0.0001), in the TT-TE distance (p<0.0042) and in the resulting TT-TG Index (p<0.0001). CONCLUSIONS: The measurement of the TT-TG Index is a reliable and differentiated approach for determining the lateral displacement of the tibial tubercle in relation to the proximal trochlear groove. The pathological influence of the TT-TG distance in case of patella instability depends on individual joint size, confirming the initial hypothesis. We currently consider a TT-TG Index>0.23 to be pathological based on our findings. Particularly, in case of a marginal TT-TG distance, the additional relative TT-TG Index facilitates a decision concerning an indication for a operative medial transfer of the tibial tubercle. LEVEL OF EVIDENCE: II.

The influence of risk factors on clinical outcomes following anatomical medial patellofemoral ligament (MPFL) reconstruction using the gracilis tendon.

PURPOSE: Patellofemoral instability is influenced by ligamentous, boney and neuromuscular factors. The most important variables are trochlea geometry, medial patellofemoral ligament (MPFL), patella height, tibial tuberosity-trochlea groove distance (TT-TG) and the extensor muscles. Treatment is complicated by these multifactorial conditions. This prospective study examined the influence of risk factors on clinical results and athletic activities where treatment was confined to ligamentous procedures only. METHODS: Fifty patients with chronic patellofemoral instability were treated with MPFL reconstruction using an autologous gracilis tendon. Clinical data, radiographs and magnetic resonance imaging (MRI) were prospectively evaluated pre- and postoperative (minimum follow-up 12 month) to detect existing risk factors for patellofemoral instability and to evaluate clinical and sport ability scores (Kujala, Valderrabano). RESULTS: There was a low rate of redislocation (2 %) and an average Kujala score of 87 ± 13 points postoperative. The MRI showed good integration of the reconstructed MPFL and a positive effect regarding the decrease of patella tilt (16.1° to 11.2°). A negative relationship was found between the degree of trochlear dysplasia and outcomes. 80 % of all patients returned to the same or higher level of physical activity. CONCLUSIONS: Addressing only ligamentous factors through MPFL reconstruction leads to satisfying clinical results and low redislocation rates in most patients. In cases with a high degree of trochlear dysplasia and enlarged TT-TG, additional procedures such as trochleaplasty and tibial tuberosity transfer should be considered as well. LEVEL OF EVIDENCE: IV.

Anterior cruciate ligament reconstruction with and without computer navigation: a clinical and magnetic resonance imaging evaluation 2 years after surgery.

PURPOSE: The purpose of this study was to evaluate the benefits of computer navigation on tunnel placement during anterior cruciate ligament reconstruction. METHODS: A prospective, randomized, controlled study comparing computer navigation with manual operation was performed between December 2003 and April 2004. We assigned 20 patients to the computer navigation group and 20 patients to the manual navigation group. Surgery was performed by use of a patellar tendon autograft with press-fit fixation. A lateral radiograph of the knee at maximum extension was used to determine the exact position of the tibial tunnel at 4 days postoperatively. Outcomes were evaluated with International Knee Documentation Committee 2000, Tegner, and Lysholm scoring. There was an additional magnetic resonance imaging (MRI) evaluation of tunnel placement and graft quality at the most recent follow-up, approximately 24 months after surgery. RESULTS: The postoperative radiographs and 2-year postoperative MRI scans showed no differences between groups for tibial or femoral tunnel placement. In both groups the mean tibial tunnel placement was 46% of the maximal diameter of the tibia. There were no significant differences between groups for objective and subjective outcomes scoring. Although some qualitative differences existed between groups with respect to MRI graft appearance at 2 years, this had no correlation with overall results. CONCLUSIONS: No significant differences were found between computer-assisted and manually navigated anterior cruciate ligament reconstruction with regard to tunnel placement and clinical results at a mean of 2 years postoperatively. LEVEL OF EVIDENCE: Level I, randomized, single-blinded, controlled trial.

Differences in the placement of the tibial tunnel during reconstruction of the anterior cruciate ligament with and without computer-assisted navigation.

BACKGROUND: Next to graft fixation, correct positioning of the tibial and femoral tunnel is a deciding factor for the clinical result of anterior cruciate ligament reconstruction surgery. Computer-assisted navigation has been proposed as a method to improve tunnel positioning. PURPOSE: To examine the differences in tibial tunnel placement between cruciate ligament operations using manual and computer-assisted navigation. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Between December 2003 and April 2004, 53 athletes underwent anterior cruciate ligament reconstruction surgery with arthroscopic press-fit technique. The first group (group N; 24 athletes) were operated on with the aid of a navigation system (OrthoPilot, Aesculap AG & Co. KG, Braun), and the second group (group M; 29 athletes) were "manually" operated on. A lateral radiograph of the knee at maximum extension was used to determine the exact position of the tibial tunnel four days postoperatively. In the measurements, the anterior and posterior boundaries of the tibial tunnel, as well as the center of the tibial tunnel in relation to the maximum tibia anteroposterior diameter were evaluated (indicated in percent). An analysis of the tibial tunnel position proportional to the slope of the intercondylar roof was done to determine intercondylar impingement (method according to Howell). The centers of the tibial tunnels were compared with the "optimal" position noted in previous studies. The standard deviation was determined for both groups to determine the variance of placement. RESULTS: The anterior tibial tunnel border was 19.4 mm in group M (29.7%) and 21.2 mm in group N (32.2%) (P = .18). The center of the tibial tunnel was located at 24.6 mm in group M (35.6%) and at 26.6 mm in group N (40.3%) (P = .19). In group M, the posterior tibial tunnel position was located at 30.2 mm (46.2%), and in group N at 32.2 mm (49.1%) (P = .21). When comparing the centers of the tibial tunnels with the optimal 44% found in previous studies, the value for group M (37.6%) varied significantly, while group N (40.5%) did not. However, there was no significant difference in the range variance for either group; the standard deviation was 6.9% (4.3 mm) for group M and 5.9% (3.5 mm) for group N. One athlete showed moderate impingement in group N, and two athletes in group M. CONCLUSION: Assisted navigation offers good support for correct placement of the tibial tunnel, although experienced surgeons can achieve essentially the same positioning as surgeons using computer-assisted navigation. Whether it is advisable to implement this procedure in daily surgical routine should be decided based on clinical results.