Recovery of Full Hyperextension after ACL Reconstruction Is Associated with Better Functional Outcomes but Greater ACL-Related Laxity after a minimum of 24 months follow up.

PURPOSE: Evaluate patients submitted to anterior cruciate ligament (ACL) reconstruction with preoperative hyperextension and compare physical examination (KT-1000 and pivot shift) and patient reported outcomes measures of patients who recovered the entire hyperextension with patients who did not. METHODS: Patients aged 18 to 60 years with more than 5 degrees of knee hyperextension submitted to anatomical ACL reconstruction with any graft from June 2013 to June 2021 and at least 24 months of follow-up were evaluated retrospectively. Hamstrings and patellar tendon grafts were fixed around 20 to 30 degrees of flexion and in full extension, respectively. Patients who could recover hyperextension were compared with patients who did not. Pre-operative, intra-operative and post-operative data, including physical examination and patient reported outcomes measures, was evaluated. RESULTS: A total of 225 patients were evaluated, 48 (21.3%) did not recover hyperextension, and 177 recovered full range of motion. Patients who did not recover hyperextension had a larger graft diameter (8.7 ± 0.7mm (confidence interval 8.502-8.898) vs. 8.3 ± 0.7mm (confidence interval 8.197-8.403); p = 0.018). Regarding the postoperative subjective variables, patients who recovered hyperextension showed improvement on all scales (IKDC, Lysholm, FJS, and GPE) evaluated compared to patients who did not recover the range of motion. Patients who recovered hyperextension also showed more laxity on physical examination, measured by the KT-1000 (1.8 ± 0.8 vs. 1.1 ± 1.0; p= 0.0006) and the pivot-shift (Grade 0 - 62.1%;Grade 1 - 37.9% vs. Grade 0 - 79.2%;Grade 1 - 20.8%; p=0.027). CONCLUSION: Patients with knee hyperextension who regained range of motion after ACL reconstruction have worse knee laxity than patients who regained full extension but not hyperextension. However, patients who recover full range of motion showed higher scores on subjective function scales, including a greater number of patients who achieved PASS IKDC.

Patients With More Than 6.5° of Knee Hyperextension are 14.6 Times More Likely to Have Anterior Cruciate Ligament Hamstring Graft Rupture and Worse Knee Stability and Functional Outcomes.

PURPOSE: To create a cut-off point for hyperextension that best discriminates retear and to verify whether this cut-off point can predict retear regardless of other characteristics after primary anterior cruciate ligament (ACL) reconstruction with hamstrings autograft. METHODS: A cohort of patients submitted to primary isolated ACL reconstruction with hamstrings autografts was retrospectively evaluated. Patients were stratified according to the degree of passive knee hyperextension measured in the normal contralateral knee. The following data were collected: patient age and sex, time from injury to surgery, knee hyperextension, KT-1000 and pivot-shift, associated meniscus injury, intra-articular graft size, follow-up time, graft failure, and postoperative Lysholm and subjective International Knee Documentation Committee scores. RESULTS: Data from 457 patients were evaluated. Median age was 31 years. Thirty-two (7.0%) presented with retear. There was a significant difference in hyperextension between patients with and without retear (P < .001), with the cut-off point established by the receiver operating characteristic curve from 6.5°. Patients with greater hyperextension had a statistically greater frequency of women, longer injury time, greater intra-articular graft diameter, greater postoperative KT-1000, and greater frequency of retear, whereas the subjective International Knee Documentation Committee and Lysholm scores were statistically lower in patients with greater hyperextension. Only hyperextension showed a statistically significant association with re-rupture (P < .001). The odds of retear in patients with hyperextension greater than 6.5 was 14.65 times the odds of patients with hyperextension less than 6.5. CONCLUSIONS: Patients with more than 6.5° of hyperextension are 14.6 times more likely to have a graft rupture than patients with lower hyperextension when submitted to ACL reconstruction with hamstring tendons. Also, they present worse knee stability by the KT-1000 test and worse functional outcomes. Therefore, patients with this degree of hyperextension should not have isolated reconstruction with hamstrings as their first choice. LEVEL OF EVIDENCE: Level III, retrospective comparative prognostic trial.

Small Hamstring Tendon Graft for Anterior Cruciate Ligament Reconstruction Combined With Anterolateral Ligament Reconstruction Results in the Same Failure Rate as Larger Hamstring Tendon Graft Reconstruction Alone.

PURPOSE: To compare patients undergoing anterior cruciate ligament (ACL) reconstruction with hamstring grafts 7 mm or less in diameter combined with anterolateral ligament (ALL) reconstruction versus isolated ACL reconstruction with grafts greater than 7 mm in diameter. METHODS: We retrospectively evaluated the descriptive data and clinical outcomes of patients who underwent primary ACL reconstruction with hamstring grafts from June 2013 to January 2020 and had a minimum follow-up period of 2 years. Patients with quadrupled or quintupled semitendinosus and gracilis autograft 7 mm or less in diameter combined with single-strand ALL reconstruction (ACL-ALL group) were matched in a 1:2 propensity ratio to patients who underwent isolated single-bundle ACL reconstruction with hamstring grafts greater than 7 mm (ACL group). RESULTS: We identified 30 patients in our database who met the criteria for the ACL-ALL group. The patients in this group were matched to 60 patients comprising the ACL group. Both groups were similar regarding all preoperative matched and unmatched variables. The mean ACL graft diameter was 6.8 ± 0.4 mm in the ACL-ALL group and 8.6 ± 0.6 mm in the ACL group (P < .001). The ACL-ALL group presented 1 failure (3.3%), and the ACL group presented 3 failures (5%) (P = .717). Postoperative KT-1000 measurements were similar between the groups (2.1 ± 1.1 mm vs 1.9 ± 1.2 mm, P = .114), as were postoperative pivot-shift grades (P = .652). Subjective International Knee Documentation Committee scores and Lysholm scores did not present any differences between the groups (P = .058 and P = .280, respectively). CONCLUSIONS: Patients who undergo combined ACL-ALL reconstruction with an ACL graft diameter of 7 mm or less can achieve similar results to patients who undergo isolated ACL reconstruction with a graft diameter greater than 7 mm. An associated ALL reconstruction can be performed to increase knee stability in patients with small-diameter hamstring grafts. LEVEL OF EVIDENCE: Level III, retrospective, comparative therapeutic trial.

The Addition of Either an Anterolateral Ligament Reconstruction or an Iliotibial Band Tenodesis Is Associated With a Lower Failure Rate After Revision Anterior Cruciate Ligament Reconstruction: A Retrospective Comparative Trial.

PURPOSE: To compare the failure rate in patients who underwent revision anterior cruciate ligament (ACL) reconstruction alone or associated with an extra-articular procedure. Secondary objectives were to compare ACL laxity, patient-reported outcome measures, and complication rates in these patients and, subsequently, to compare the outcomes of patients who underwent revision ACL reconstruction associated with anatomical anterolateral ligament (ALL) reconstruction or lateral extra-articular tenodesis (LET). METHODS: This was a retrospective comparative study. Patients were classified into 2 groups, according to whether (group 2) or not (group 1) an extra-articular reconstruction was performed. Patients who underwent an extra-articular procedure were further divided into ALL reconstruction (group 2A) and LET (group 2B). Baseline demographic variables, operative data and postoperative data were evaluated. RESULTS: The groups with (86 patients) and without (88 patients) an associated extra-articular reconstruction had similar preoperative data. Group 2 had a lower failure rate (4.6% vs 14.7%; P = .038), better KT-1000, better pivot-shift, and better Lysholm. There was no difference regarding complications, except more lateral pain in group 2. Regarding the groups who underwent ALL reconstruction (41 patients) and LET (46 patients), group 2A showed better Lysholm scores. Both groups had similar failure rates and complications. CONCLUSIONS: Patients who underwent revision ACL reconstruction with a laterally based augmentation procedure had a lower failure rate than patients who underwent isolated revision ACL reconstruction. KT-1000 and pivot-shift examination were also significantly better when a lateral augmentation was performed. Complications were similar except for an increase in lateral pain in the augmented group. No clinically important differences were found when comparing the LET group to the ALL group other than a statistical improvement in the Lysholm functional scale, likely not clinically meaningful, favoring the ALL group and an increased duration of post-operative lateral pain in the LET group. LEVEL OF EVIDENCE: III, retrospective comparative therapeutic trial.

Surgical Timing Does Not Interfere on Clinical Outcomes in Combined Reconstruction of the Anterior Cruciate Ligament and Anterolateral Ligament: A Comparative Study With Minimum 2-Year Follow-Up.

PURPOSE: To compare the functional outcomes, knee stability, failure rate and complication rates of combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstruction with hamstrings grafts between acute and chronic cases. METHODS: Consecutive patients who underwent combined ACL and ALL reconstruction with hamstrings grafts were evaluated. Patients operated on less than 8 weeks after injury were allocated to group 1, and the others were allocated to group 2. Demographic data, knee stability, and functional outcomes of the 2 groups were evaluated. RESULTS: Thirty-four patients in the acute group and 96 in the chronic group were evaluated. The follow-up time was similar between the groups (28.7 ± 5.2 [24-43] months vs 29.4 ± 7.2 [24-58] months; P = 0.696). No differences were found between the groups in age, sex, trauma mechanism, presence of knee hyperextension, graft diameter, and meniscal injuries. There was no difference between the groups in the postoperative KT-1000 and in the pre- or postoperative pivot shift. The preoperative KT-1000 was higher in group 2 (7.9 ± 1.1 vs 7.4 ± 1.2; P = 0.031). There were no differences in the International Knee Documentation Committee or Lysholm. Three (2.3%) patients developed failure, 1 (2.9%) in group 1 and 2 (2.1%) in group 2. The total complication rate was 10% and did not differ between the groups. CONCLUSIONS: Combined ACL and ALL reconstruction has similar outcomes in patients undergoing surgery in the acute and chronic phases. Patients with chronic injury have similar knee stability, functional scores, and failure rates as acute-injury patients, and patients with acute injury have no more complications than chronic patients. LEVEL OF EVIDENCE: Level III, retrospective comparative therapeutic trial.

Degenerative Medial Meniscus Tear With a Displaced Flap Into the Meniscotibial Recess and Tibial Peripheral Reactive Bone Edema Presents Good Results With Arthroscopic Surgical Treatment.

PURPOSE: To report the arthroscopic treatment results of a degenerative medial meniscus tear with a displaced flap into the meniscotibial recess, tibial peripheral reactive bone edema, and focal knee medial pain. As a secondary objective, we propose to identify possible factors associated with a good or poor prognosis of the surgical treatment of this lesion. METHODS: From 2012 to 2018, patients who had this specific meniscus pathology and underwent arthroscopic surgical treatment were retrospectively evaluated. Patients with Kellgren-Lawrence (KL) classification greater than 2 were excluded. KL classification, the presence of an Outerbridge grade III/V chondral lesion of the medial compartment, limb alignment, body mass index, and smoking were evaluated. The subjective outcomes included the International Knee Documentation Committee score, improvement in the pain reported by patients, and the Global Perceived Effect (GPE) scale score. RESULTS: A total of 69 patients were evaluated. The mean age was 58.6 ± 7.1 years. The follow-up time was 48.7 ± 20.8 months. Fifty-five (79.7%) patients reported pain improvement. The postoperative International Knee Documentation Committee was 62.6 ± 15.4, and the mean GPE was 2.3 ± 2.6. Fourteen patients (20.3%) showed no improvement in pain, and 7 patients (10.2%) presented complications. Groups that improved (GPE > 0) and did not improve (GPE < 0) did not present differences regarding age, sex, follow-up time, chondral lesions, or body mass index. Patients without improvement had a greater incidence of smoking (P = .001), varus alignment (P = .008), and more advanced KL classification (P < .001). In the multivariate analysis based on the GPE score, KL classification (P = .038) and smoking (P = .003) were significant. CONCLUSIONS: Arthroscopic surgical treatment of degenerative medial meniscal tears with a meniscal flap displaced into the meniscotibial recess and adjacent focal bone edema in the tibia shows good results in approximately 80% of cases. Smoking and KL grade 2 were factors associated with poor prognosis of surgical treatment. LEVEL OF EVIDENCE: Level IV (case series).

The use of negative-pressure wound therapy after total knee arthroplasty is effective for reducing complications and the need for reintervention.

BACKGROUND: Wound healing complications are causal factors of prosthesis infection and poor postoperative evolution of patients after total knee arthroplasty (TKA). Negative-pressure wound therapy (NPWT) can be an option to minimize these complications. The aim of this study is to compare the complications of patients undergoing TKA who used a portable NPWT device in the immediate postoperative period with those of a control group. METHODS: A total of 296 patients were evaluated. Patients were divided into two groups: those who used NPWT for seven days in the postoperative period (Group 1 - prospective evaluated) and those who used conventional dressings (Group 2 - historical control group). Epidemiological data, comorbidities, local parameters related to the surgical wound and complications were evaluated. RESULTS: The groups did not differ in regard to sex, age and clinical comorbidities. Overall, 153 (51.7%) patients had at least one risk factor for wound complications. Patients who used NPWT had a lower rate of complications (28.5% vs. 45.7%, p = 0.001) and a lower rate of reintervention in the operating room (2% vs. 8.5%, p = 0.001). Patients in group 1 had a lower incidence of hyperaemia (14.7% vs. 40.2%, p = 0.01), skin necrosis (2.1% vs. 8.5%, p = 0.04) and wound dehiscence (3.1% vs 10.1%, p = 0.03). The use of NPWT was a protective factor for the presence of complications, with an odds ratio of 0.36 (95% CI 0.206-0.629). CONCLUSION: The number of complications related to the wound after TKA is high; however, most of them are minor and have no impact on the treatment and clinical evolution of patients. The use of NPWT decreased the number of surgical wound complications, especially hyperaemia, dehiscence and necrosis, and reduced the need for reintervention.

Bacteria drug resistance profile affects knee and hip periprosthetic joint infection outcome with debridement, antibiotics and implant retention.

BACKGROUND: Evaluate the effect of bacteria drug resistance profile on the success rates of debridement, antibiotics and implant retention. METHODS: All early acute periprosthetic infections in hip and knee arthroplasties treated with DAIR at our institution over the period from 2011 to 2015 were retrospectively analyzed. The success rate was evaluated according to the type of organism identified in culture: multidrug-sensitive (MSB), methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Gram-negative bacteria (MRB) and according to other risk factors for treatment failure. The data were analyzed using univariate and multivariate statistics. RESULTS: Fifty-seven patients were analyzed; there were 37 in the multidrug-sensitive bacteria (MSB) group, 11 in the methicillin-resistant Staphylococcus aureus (MRSA) group and 9 in the other multidrug-resistant Gram-negative bacteria (MRB) group. There was a statistically significant difference (p < 0.05) in the treatment failure rate among the three groups: 8.3% for the MSB group, 18.2% for the MRSA group and 55.6% for the MRB group (p = 0.005). Among the other risk factors for treatment failure, the presence of inflammatory arthritis presented a failure rate of 45.1 (p < 0.05). CONCLUSION: DAIR showed a good success rate in cases of early acute infection by multidrug-sensitive bacteria. In the presence of infection by multidrug-resistant bacteria or association with rheumatic diseases the treatment failure rate was higher and other surgical options should be considered in this specific population. The MRSA group showed intermediate results between MSB and MRB and should be carefully evaluated.

Clinical results of pulsed signal therapy on patellofemoral syndrome with patellar chondropathy.

This study was designed to evaluate the effect of pulsed signal therapy (PST) on patellofemoral pain syndrome associated with patellar chondropathy. A prospective randomized double-blind placebo controlled trial included 25 patients (41 knees) between 20 and 50 years with pain due to isolated patellofemoral syndrome with chondropathy. PST group received nine 60-min daily sessions of PST treatment. Control group received the same protocol of blinded placebo treatment. The main outcome was change from baseline Kujala score at 3 months. After 3 months, patients in the control group received effective treatment (placebo post-treatment). All patients were then followed, for up to 12 months. Seventeen knees (5 males and 12 females, mean age 36.7 ± 7.9) received placebo and 24 knees (8 males and 16 females, mean age 35.5 ± 8.9) received PST. By the third month, PST group exhibited a mean change from baseline of 9.63 ± 7.5 Kujala points, compared to 0.53 ± 1.8 in the placebo group (P < 0.001). A significant progressive improvement was seen in the PST group between the 3rd and 6th and between the 6th and 12th month (P < 0.016). Patients initially allocated in the control group also improved at 3 months (P < 0.001) and 6 months (P = 0.005) post-effective treatment. In conclusion, PST in patellofemoral pain syndrome with chondropathy was effective compared to placebo at 3 months, showing an important improvement of Kujala score. The improvement was progressive and maintained up to 12 months. PST is safe and should be considered as a non-invasive option for management of this condition. Bioelectromagnetics. 40:83-90, 2019. © 2019 Bioelectromagnetics Society.

Combined Reconstruction of the Anterolateral Ligament in Patients With Anterior Cruciate Ligament Injury and Ligamentous Hyperlaxity Leads to Better Clinical Stability and a Lower Failure Rate Than Isolated Anterior Cruciate Ligament Reconstruction.

PURPOSE: To compare functional outcomes, residual instability, and rupture rates in patients with ligamentous hyperlaxity undergoing isolated anterior cruciate ligament (ACL) reconstruction or combined ACL and anterolateral ligament (ALL) reconstruction. METHODS: Two groups of patients were evaluated and compared retrospectively. Both groups consisted of patients with ACL injuries and associated ligamentous hyperlaxity, defined based on the modified Beighton scale with a minimum score of 5. Group 1 patients underwent anatomical ACL reconstruction, and group 2 patients underwent anatomical ACL reconstruction combined with ALL reconstruction. Group 1 consisted of historical controls. The presence of associated meniscal injury, subjective International Knee Documentation Committee and Lysholm functional scores, KT-1000 measurements, the presence of a residual pivot-shift, and the graft rupture rate were evaluated. The study was performed at University of São Paulo in Brazil. RESULTS: Ninety patients undergoing ACL reconstruction with ligamentous hyperlaxity were evaluated. The mean follow up was 29.6 ± 6.2 months for group 1 and 28.1 ± 4.2 months for group 2 (P = .51). No significant differences were found between the groups regarding Beighton scale, gender, the duration of injury before reconstruction, follow-up time, preoperative instability, or associated meniscal injuries. The mean age was 29.9 ± 8.1 years in group 1 and 27.0 ± 9.1 years in group 2 (P = .017). In the final evaluation, group 2 patients showed better anteroposterior clinical stability as evaluated by KT-1000 arthrometry (P = .02), better rotational stability as evaluated by the pivot-shift test (P = .03) and a lower reconstruction failure rate (21.7% [group 1] vs 3.3% [group 2]; P = .03). Clinical evaluations of postoperative functional scales showed no differences between the 2 groups (P = .27 for International Knee Documentation Committee; P = .41 for Lysholm). CONCLUSIONS: Combined ACL and ALL reconstruction in patients with ligamentous hyperlaxity resulted in a lower failure rate and improved knee stability parameters compared to isolated ACL reconstruction. No differences were found in the functional scales. LEVEL OF EVIDENCE: Level III, case control study.

Combined reconstruction of the anterolateral ligament in chronic ACL injuries leads to better clinical outcomes than isolated ACL reconstruction.

PURPOSE: To evaluate the results of combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstruction in patients with chronic ACL injury. It was hypothesized that patients who underwent combined ACL and ALL reconstruction would exhibit less residual laxity and better clinical outcomes. METHODS: Two groups of patients were evaluated and compared retrospectively. Both groups consisted only of patients with chronic (more than 12 months) ACL injuries. Patients in group 1 underwent anatomical intra-articular reconstruction of the ACL and patients in group 2 underwent anatomic intra-articular ACL reconstruction combined with ALL reconstruction. The presence of associated meniscal injury, the subjective International Knee Documentation Committee (IKDC) and Lysholm functional outcome scores in the postoperative period, KT-1000 evaluation, the presence of residual pivot shift and graft rupture rate were evaluated. RESULTS: One hundred and one patients who underwent reconstruction of chronic ACL injuries were evaluated. The median follow-up was 26 (24-29) months for group 1 and 25 (24-28) months for group 2. There were no significant differences between groups regarding gender, age, duration of injury until reconstruction, follow-up time or presence of associated meniscal injuries in the preoperative period. Regarding functional outcome scores, patients in group 2 presented better results on both the IKDC (p = 0.0013) and the Lysholm (p < 0.0001) evaluations. In addition, patients in group 2 had better KT-1000 evaluation (p = 0.048) and a lower pivot shift rate at physical examination, presenting only 9.1% positivity versus 35.3% in the isolated ACL reconstruction (p = 0.011). Regarding re-ruptures, group 1 presented 5 (7.3%) cases, and group 2 presented no cases. CONCLUSION: The combined ACL and ALL reconstruction in patients with chronic ACL injury is an effective and safety solution and leads to good functional outcomes with no increase in complication rate. The clinical relevance of this finding is the possibility to indicate this type of procedure when patients present with more than 12 months after injury for surgery. LEVEL OF EVIDENCE: Level III.

Medial Patellofemoral Ligament, Medial Patellotibial Ligament, and Medial Patellomeniscal Ligament: Anatomic, Histologic, Radiographic, and Biomechanical Study.

PURPOSE: To describe the anatomy (quantitative macroscopic and histologic), radiographic parameters of the insertions, and biomechanical characteristics of the medial ligamentous restrictors of the patella (medial patellofemoral ligament [MPFL], medial patellotibial ligament [MPTL], and medial patellomeniscal ligament [MPML]) in cadaveric knees. Because the MPTL and the MPML are not as well known as the MPFL, they were the focus of this study. METHODS: MPFLs, MPTLs, and MPMLs from 9 knees were dissected. Histologic evaluations were conducted. Length, width, and insertion relations with anatomic references were determined. Metallic spheres were introduced into the insertion points of each ligament, and anteroposterior and lateral radiographs were taken. The distances of the insertions from the baselines were measured on radiographs. Tensile tests of the ligaments were performed. RESULTS: All the samples showed dense connective tissue characteristic of ligaments. The MPTL was inserted into the proximal tibia (13.7 mm distal to the joint line) and in the distal end of the patella (3.6 mm proximal to the distal border). The MPTL had a length of 36.4 mm and a width of 7.1 mm. The MPML was inserted into the medial meniscus and distally in the patella (5.7 mm proximal to the distal border). Per radiography, on the anteroposterior view, the tibial insertion of the MPTL was 9.4 mm distal to the joint line and in line with the medial border of the medial spine. On the lateral view, the patellar insertions of the MPTL and MPML were 4.8 and 6.6 mm proximal to its distal border, respectively. The MPTL was stiffer than the MPFL (17.0 N/mm vs 8.0 N/mm, P = .024) and showed less deformation in the maximum tensile strength (8.6 mm vs 19.3 mm, P = .005). CONCLUSIONS: The MPTL inserts into the proximal tibia and into the distal pole of the patella. The MPML inserts into the medial meniscus and into the distal pole of the patella. They present with identifiable anatomic and radiographic parameters. Grafts commonly used for ligament reconstructions should be adequate for reconstruction of the MPTL. CLINICAL RELEVANCE: The study contributes to the anatomic, radiographic, and biomechanical knowledge of the MPTL to improve the outcomes of its reconstruction.

Combined reconstruction of the posterior cruciate ligament and medial collateral ligament using a single femoral tunnel.

PURPOSE: Lesions of the medial collateral ligament (MCL) are the most common knee ligament injuries, and lesions associated with the anterior cruciate ligament or the posterior cruciate ligament (PCL) in knee dislocations should be reconstructed to prevent failure of the central pivot reconstruction. The purpose of this study was to evaluate the outcomes of combined PCL/MCL reconstruction using a single femoral tunnel with a minimum 2-year follow-up. METHOD: A retrospective study of thirteen patients with combined PCL/MCL injuries was conducted. The patients underwent PCL and MCL reconstruction using an Achilles tendon allograft with a single tunnel in the medial femoral condyle, thereby avoiding tunnel conversion. RESULTS: All patients achieved a range of motion of at least 100°. The mean loss of extension and flexion values compared to the contralateral side was 1° ± 2° and 9° ± 10°, respectively. Our results included 26 reconstructions with three (11.5 %) failures, two in the PCL (15.3 %) and one in the MCL (7.6 %), in three different patients. In the final evaluation, the mean IKDC subjective score was 71.63 ± 16.23, the mean Lysholm score was 80.08 ± 13.87, and the median Tegner score was 6 (range = 2-7). CONCLUSION: The PCL/MCL reconstruction technique using a single femoral tunnel and an Achilles tendon allograft is safe, avoids the convergence of tunnels in the medial femoral condyle, has excellent results, and is reproducible. LEVEL OF EVIDENCE: IV.

Why are bone and soft tissue measurements of the TT-TG distance on MRI different in patients with patellar instability?

PURPOSE: To determine whether the tibial tuberosity-to-trochlear groove distance (TT-TG) and patellar tendon-to-trochlear groove distance (PT-TG) are equal, whether the bony and cartilaginous points coincide in the trochlea, and whether the insertion of the PT coincides with the most anterior point of the TT in patients with patellar instability. METHODS: Fifty-three MRI scans of patients with patellar instability were examined. TT-TG and PT-TG were measured by three examiners in 31 knees. Additionally, the bone-cartilage distance in the trochlea [trochlear cartilage to trochlear bone (TC-TB)] and the distance between the mid-point of the PT insertion and the most anterior point of the TT (PT-TT) were measured by one examiner. The intraclass correlation coefficient was used to evaluate the reliability of the measurements between the three examiners. The relationships between the measurements were determined, the means of the measurements were calculated, and the correlations between PT-TG and TT-TG, PT-TT, and TC-TB were assessed. RESULTS: The ICC was above 0.8. PT-TG was 3.7 mm greater than TT-TG. The TC and TB coincided in 73 % of cases, and the mean TC-TB was 0.3 mm. The PT was lateral to the TT in 94 % of the cases, and the mean PT-TT was 3.4 mm. The Pearson's correlation coefficients between PT-TG and TT-TG, PT-TT, and TC-TB were 0.946, 0.679, and 0.199, respectively. CONCLUSION: TT-TG underestimated PT-TG, primarily due to the lateralization of the PT insertion relative to the most anterior point of the TT. CLINICAL RELEVANCE: our study shows that in patients with patellar instability, there are differences in the absolute values of TT-TG and PT-TG, as previously reported for patients without patellar instability. Hence, normal cut-off values based on case-control studies of TT-TG cannot be equivalently used when measuring PT-TG to indicate TT medialization in patients with patellar instability. It is also important to note that the clinical outcomes cannot be directly compared between patients evaluated using TT-TG versus PT-TG measurements. LEVEL OF EVIDENCE: III.

Patellar tracking after isolated medial patellofemoral ligament reconstruction: dynamic evaluation using computed tomography.

PURPOSE: Medial patellofemoral ligament (MPFL) reconstruction offers good clinical results with a very low rate of instability recurrence. However, its in vivo effect on patellar tracking is not clearly known. The aim of this study is to investigate the effects of MPFL reconstruction on patellar tracking using dynamic 320-detector-row CT. METHODS: Ten patients with patellofemoral instability referred to isolated MPFL reconstruction surgery were selected and subjected to dynamic CT before and ≥6 months after surgery. Patellar tilt angles and shift distance were analysed using computer software specifically designed for this purpose. Kujala and Tegner scores were applied, and the radiation of the CTs was recorded. Two protocols for imaging acquisition were compared: a tube potential of 80 kV and 50 mA versus a tube potential of 120 kV and 100 mA, both with a slice thickness of 0.5 mm and an acquisition duration of 10 s. RESULTS: There were no changes in patellar tracking after MPFL reconstruction. There was no instability relapse. Clinical scores improved from a mean of 51.9 (±15.6)-74.2 (±20.9) on the Kujala scale (p = 0.011) and from a median of 2 (range 0-4) to 4 (range 1-6) on the Tegner scale (p = 0.017). The imaging protocols produced a dose-length product (DLP) of 254 versus 1617 mGycm and a radiation effective estimated dose of 0.2 versus 1.3 mSv, respectively. Both protocols allowed the analysis of the studied parameters without loss of precision. CONCLUSIONS: Reconstruction of the MPFL produced no improvement in patellar tilt or shift in the population studied. The low-radiation protocol was equally effective in measuring changes in patellar tracking and is recommended. Although the procedure successfully stabilized the patella, knee surgeons should not expect patellar shift and tilt correction when performing isolated patellofemoral ligament reconstruction in patients with recurrent patellar instability. LEVEL OF EVIDENCE: IV.

Biomechanical study of strength and stiffness of the knee anterolateral ligament.

BACKGROUND: Recent studies clearly characterize the anatomical parameters of the knee anterolateral ligament (ALL). The potential clinical importance of this ligament is exemplified by some patients with possible combined Anterior Cruciate Ligament (ACL) and ALL rupture who do not progress satisfactorily following isolated ACL reconstruction. Previous biomechanical studies have assessed the resistance parameters of the ALL in order to address potential reconstruction strategies; however, these have reported conflicting results. Thus, this study aimed to evaluate the linear resistance of the ALL by means of a biomechanical study in cadaveric knees. METHODS: Fourteen cadaveric knees were used. The ALL was dissected, and all structures that connect the femur and the tibia, except for the ALL, were sectioned. The ALL was subjected to a tensile test with the knee around 30 to 40 degrees, in a way that the ALL was aligned with the machine. The strength at the maximum resistance limit, deformation and stiffness of the ALL were evaluated. RESULTS: The mean maximum strength of the ALL was 204.8 +/- 114.9 N. The stiffness was 41.9 +/- 25.7 N/mm and the deformation 10.3 +/- 3.5 mm. CONCLUSION: The ALL has a mean ultimate tensile strength of 204.8 N. This suggests that simple bands of all autologous or homologous grafts commonly used in clinical practice for ligament reconstruction around the knee possess the required biomechanical resistance characteristics for ALL reconstruction.

Is it safe to reconstruct the knee Anterolateral Ligament with a femoral tunnel? Frequency of Lateral Collateral Ligament and Popliteus Tendon injury.

PURPOSE: This study sought to determine the safety limits for performing a femoral bone tunnel to reconstruct the knee anterolateral ligament (ALL) by establishing its distance from the lateral collateral ligament (LCL) and the popliteus muscle tendon (PT) on the lateral femoral condyle. METHODS: Anatomic study on 48 knee cadaveric specimens. The femoral attachments of the studied structures were isolated, and the distance between them was measured. For each cadaver, the percentage of cases in which at least 50 % of the LCL and PT would be injured when using 4- to 12-mm-diameter drills in an ALL reconstruction procedure was evaluated. RESULTS: The LCL and PT were 3.8 mm and 10.2 mm distant from the ALL, respectively. A 4-mm tunnel would cause LCL injury in 8.3 % of cases, with increasing incidence of injury up to 87.5 % with a 12-mm drill. Injury to the PT would start with the 10-mm drill, causing injury in 2.0 % of cases. CONCLUSIONS: Performing a tunnel in the center of the ALL may cause an iatrogenic injury to the LCL origin. No cases of PT injury are expected to occur with drills smaller than 10 mm.

The meniscal insertion of the knee anterolateral ligament.

PURPOSE: The aim of this study is to characterize in detail the meniscal insertion of the anterolateral ligament (ALL) of the knee, establishing parameters regarding the circumference of the lateral meniscus and the popliteal muscle tendon (PMT) groove in addition to its histological analysis. METHODS: A total of 33 knees of cadavers were dissected. The ALL and the lateral meniscus were removed en bloc. After removal of the anatomical specimen, the meniscus circumference, the ALL insertion points on the external surface of the lateral meniscus, and the PMT groove were measured. Eight menisci were subjected to histological analysis. RESULTS: The ALL was found in all dissections performed. The ALL insertion occurred macroscopically in the transition between the anterior horn and the lateral meniscus body, specifically beginning at 36.0% and ending at 41.9% of the meniscal circumference, occupying a mean area of 5.6 mm. The distance between the end of the ALL meniscal insertion and the beginning of the PMT groove averaged 12.9 mm. In the histological evaluation, in longitudinal sections, we observed dense collagen fibers of the ligament inserting on the external surface of the meniscus. It is possible to observe a spreading of collagen fibers at the moment of meniscal insertion. CONCLUSIONS: The ALL meniscal insertion was found in all dissected specimens, beginning with approximately 36% of the meniscal outer diameter, 12.9 mm anterior to the beginning of the PMT groove. The histological analysis confirmed the presence of true ligamentous tissue in the dissected specimens.

Are the osseous and tendinous-cartilaginous tibial tuberosity-trochlear groove distances the same on CT and MRI?

OBJECTIVE: To verify whether the tibial tuberosity-trochlear groove distance (TT-TG) and the tendinous-cartilaginous TT-TG (the distance between the patellar tendon and trochlear groove: PT-TG) are identical using computed tomography (CT) and magnetic resonance imaging (MRI) techniques. SUBJECTS AND METHODS: The TT-TG and PT-TG distances were measured on the same knee samples by three observers (two measurements per observer) using CT and MRI scans collected retrospectively. The reproducibility of the measurements was assessed using the interclass correlation coefficient (ICC). The means and standard deviations of four measurements were calculated for each patient. A paired t-test was used to assess differences between measurements. RESULTS: Fifty knee samples (32 with patellar instability and 18 with other conditions) were evaluated. The inter- and intraobserver reliability was excellent for all four measurements (>0.8). On average, the TT-TG distance on MRI was 3.1-3.6 mm smaller than that on CT, and the PT-TG distance on MRI was 1.0-3.4 mm larger than the TT-TG distance on MRI. CONCLUSION: The osseous TT-TG and tendinous-cartilaginous PT-TG distances determined by CT and MRI were not identical.

External fixator for treatment of the sub-acute and chronic multi-ligament-injured knee.

PURPOSE: To assess whether the use of an articulated external fixator provides improvements in the mobility, stability and subjective function of patients undergoing ligament reconstruction. METHODS: Thirty-three patients with sub-acute and chronic knee dislocation were subjected to multi-ligament reconstruction surgery. These patients were randomly allocated to two groups for immobilization after reconstruction: group 0-control (18 patients), with rigid knee bracing, and group 1-articulated external fixator (15 patients). The stability of the reconstructed ligaments was assessed after at least 14 months (26.6-month average) postoperatively by physical examination. Deficit of extension and flexion was measured in relation to the unaffected contralateral knee, and the Lysholm knee scoring scale questionnaire was applied. RESULTS: There was no difference in the assessment of joint stability between the groups. In group 1, patients showed less flexion deficit (4.8° ± 5.4° vs. 18.2° ± 14.8°, p < 0.05), and the percentage of patients with a flexion deficit of 5° or less were higher compared with group 0 (64 vs. 18 %, p < 0.05). There was no difference between groups in relation to extension loss. Group 1 also presented better Lysholm scores, with 73 % of patients rated as excellent or good compared with 35 % in group 0 (p < 0.05). CONCLUSIONS: Compared with the control rehabilitation protocol with rigid knee bracing in extension, the use of an articulated external fixator in the treatment of chronic multi-ligament-injured knees provided the same ligament stability, better final range of motion and improved Lysholm score. Patients presenting with chronic multi-ligament instability should be considered for articulated external fixation to supplement reconstruction procedures. LEVEL OF EVIDENCE: Randomized controlled trial, Level I.