Paul A. Martineau

The Apex of the Deep Cartilage: A Landmark and New Technique to Help Identify Femoral Tunnel Placement in Anterior Cruciate Ligament Reconstruction

PURPOSEnThe purpose of this study was to evaluate the apex of the deep cartilage (ADC) as a landmark to help guide femoral tunnel placement during anatomic single-bundle anterior cruciate ligament (ACL) reconstruction. Our secondary purpose was to assess whether or not the endoscopic transtibial femoral offset drill guide could reach the center of the ACLs femoral footprint.nnnMETHODSnEight formalin-injected cadaveric knees were dissected and the center of the ACL femoral footprints identified. The ADC was selected as an easily identifiable landmark during arthroscopy and was used to reference the position of the ACL femoral footprint with the knee flexed at 90°. Next, a 7-mm transtibial femoral ACL drill guide was used to engage the posterior aspect of the lateral condyle at the level of the femoral footprint. This position was marked, and the distance from the center of the femoral footprint was recorded for each specimen. Descriptive statistics were used to report our measurements.nnnRESULTSnThe median high and shallow measurements were 3 mm (range, 1 to 4 mm) and 12 mm (range, 11 to 17 mm), respectively. The femoral offset guide never reached the center of the femoral footprint in all specimens; the median distance between the 2 measurements was 4.5 mm (range, 2 to 9 mm).nnnCONCLUSIONSnIf the anatomy is difficult to delineate at the time of reconstruction, our study suggests using the ADC as a landmark to guide anatomic placement. The dissection of 8 cadavers showed that the center of the ACL femoral footprint had a median position of 3 mm high and 12 mm shallow to the ADC. We also showed that the transtibial femoral offset guide did not reach the center of the ACL footprint on all specimens and should therefore not be used for anatomic ACL reconstruction.nnnCLINICAL RELEVANCEnCurrent commercially available transtibial femoral offset guides cannot reach the center of the ACLs femoral footprint and therefore should not be used. Alternative techniques, such as referencing from the ADC through an anteromedial (AM) portal, are recommended.

Risk of Glove Perforation With Arthroscopic Knot Tying Using Different Surgical Gloves and High–Tensile Strength Sutures

PURPOSEnTo examine the risk of glove tears associated with arthroscopic knot tying using 4 commonly used high-tensile strength sutures and 2 different types of gloves.nnnMETHODSnWe analyzed 2 different surgical latex glove types (0.24-mm-thick powder-free and 0.32-mm-thick powdered) for perforation after arthroscopic knot tying with 4 different high-tensile strength sutures: Hi-Fi (ConMed Linvatec, Largo, FL), Ultrabraid (Smith & Nephew, Memphis, TN), FiberWire (Arthrex, Naples, FL), and Orthocord (DePuy Mitek, Raynham, MA). All knots were tied by a double-gloved single surgeon. Twelve trials of 4 knots each were performed for every glove-suture combination. All gloves were analyzed for perforation by a blinded evaluator using visual inspection, hydro-insufflation, and electroconductivity.nnnRESULTSnThe overall incidence of glove perforation was 3.4% and was detectable only by the electroconductivity method; the other 2 methods did not detect any perforations. There was a statistically significantly higher rate (P < .001) of perforations in the 0.32-mm powdered gloves (6.8%) compared with the 0.24-mm powder-free gloves (0%). Perforation of the inner glove occurred 5.7 times more frequently than perforation of the outer glove. However, simultaneous perforation of both the inner and outer gloves did not occur in any set. The Hi-Fi suture was involved in 6 perforations compared with 4 for FiberWire, 3 for Ultrabraid, and 0 for Orthocord.nnnCONCLUSIONSnDouble gloving provides an adequate surgical barrier between the surgeon and the patient during arthroscopic knot tying with high-tensile strength sutures as indicated by the low incidence of glove perforations in our study in an in vitro biomechanical evaluation. There were no instances of simultaneous perforation of both the inner and outer gloves. All perforations occurred only in the thicker (0.32-mm) powdered gloves.nnnCLINICAL RELEVANCEnGlove tears and finger lacerations have been reported with the use of high-tensile strength sutures during arthroscopic shoulder surgery, thereby raising a concern for safety and disease transmission. This study addresses these concerns by evaluating the risk of glove tears during arthroscopic knot tying.

A cadaveric analysis of tunnel position created using flexible versus rigid instrumentation in a single-incision distal biceps tendon repair.

PURPOSEnThis study was designed to determine whether the use of a flexible guide pin and reamer through an anterior single-incision approach would allow for a more anatomic insertion point on the radial tuberosity when compared with the traditional rigid instrumentation used for cortical button fixation.nnnMETHODSnSeven matched pairs of fresh-frozen cadaveric upper extremity specimens were used in this study. One specimen from each matched pair was randomly assigned to undergo a simulated repair using the standard instrumentation required for a cortical button fixation device, and the other specimens were assigned to undergo the same repair using a 42° anterior cruciate ligament femoral guide with a flexible guide pin and reamer. Each specimen from both groups was positioned with the elbow in 90° of flexion and the forearm maximally supinated during guide pin insertion. The proximal portion of the radius was then harvested from the specimen and scanned using micro-computed tomography (micro-CT). Tunnel position between the 2 techniques was compared with the center of the native tendon footprint.nnnRESULTSnThe mean percentage of the reamed entry hole within the tendon footprint was significantly less using rigid instrumentation (36.35%) compared with flexible instrumentation (67.29%) (P = .043). Furthermore, when flexible reamers were used (mean offset ratio, 0.17), the resultant tunnel was positioned in a significantly more central position within the radial shaft (i.e., the offset ratio was lower) compared with rigid reamers (mean offset ratio, 0.35) (P = .043). The entry hole was found to be significantly more posterior relative to the center of the anatomic footprint for the flexible reamer group (mean, 0.21 mm anterior) compared with the rigid reamer group (mean, 3.22 mm anterior) (P = .028). There was no difference in tunnel length between the 2 groups.nnnCONCLUSIONSnThe use of a flexible guide pin and reamer allows for a more anatomically positioned repair than does rigid instrumentation through a single-incision approach.nnnCLINICAL RELEVANCEnThis surgical technique allows for a more anatomic re-creation of the distal biceps tendon insertion while maintaining the benefits of a single limited anterior exposure.

Drill wobble – effect on femoral tunnel aperture during anterior cruciate ligament reconstruction

BackgroundIn anterior cruciate ligament reconstruction performed using cortical button fixation on the femur, we have observed a “wobble” effect that can occur when a cannulated femoral drill is used over a guide pin that is not securely fixed in bone. Our study assessed the effect of drill “wobble” on femoral tunnel aperture in sawbones.MethodsFemoral tunnels were drilled in sawbones, which had been divided in two groups of 10 each, per drilling technique. The “wobble” technique group had the smaller cortical button drill passed before drilling the graft socket with the bigger diameter femoral drill. In contrast, in the “non-wobble” technique group, the smaller cortical button drill was passed after drilling the graft socket. The aperture dimensions: antero-posterior, proximo-distal and oblique, as well as the length of each tunnel, were measured.ResultsWhile the average dimensions of the tunnels were similar between the two techniques, there was significantly more variation in the antero-posterior measurements for the wobble technique as compared to the non-wobble technique (mean 7.3xa0mm, SD 0.28xa0mm, and mean 7.3xa0mm, SD 0.11xa0mm, respectively; Brown-Forsythe test, p 0.02).ConclusionWe conclude that using the “socket first” “non-wobble” technique is a single surgical technical step surgeons can employ to decrease variability in tunnel aperture and size.

Fixation strength of four headless compression screws.

To promote a quicker return to function, an increasing number of patients are treated with headless screws for acute displaced and even non-displaced scaphoid fractures. Therefore, it is imperative to understand and optimize the biomechanical characteristics of different implants to support the demands of early mobilization. The objective of this study was to evaluate the biomechanical fixation strength of 4 headless compression screws under distracting and bending forces. The Acutrak Standard, Acutrak Mini, Synthes 3.0, and Herbert-Whipple screws were tested using a polyurethane foam scaphoid fracture model. Implants were inserted into the foam blocks across a linear osteotomy. Custom fixtures applied pull-apart and four-point bending forces until implant failure. Pull-apart testing was performed in three different foam densities in order to simulate osteoporotic, osteopenic, and normal bone. The peak pull-apart forces varied significantly between implants and were achieved by (from greatest to least): the Acutrak Standard, Synthes 3.0, Acutrak Mini, and Herbert-Whipple screws. The fully threaded screws (Acutrak) failed at their proximal threads while the shanked screw (Synthes and Herbert Whipple) failed at their distal threads. Similarly, the screws most resistant to bending were (from greatest to least): the Acutrak Standard, Acutrak Mini, Herbert-Whipple, and Synthes. Although the amount of force required for pull-apart failure increased with each increasing simulated bone density (a doubling in density required triple the amount of pull apart force), the mode and sequence of failure was the same. Overall, the fully threaded, conical design of the Acutrak screws demonstrated superior fixation against pull-apart and bending forces than the shanked designs of the Synthes and Herbert-Whipple. We also found a strong relationship between simulated bone density and pull-apart force.

Anterolateral Ligament Injury in Knee Dislocations

PURPOSEnThe purpose of this study is to describe the prevalence and associated factors of anterolateral ligament (ALL) injury in knee dislocation (KD).nnnMETHODSnA retrospective review of charts and radiological images was done for patients who underwent multiligamentous knee reconstruction surgery for KD in the authors institution from May 2008 to December 2016. The inclusion criteria were both genders, skeletally mature, and first dislocation. Previous anterior cruciate ligament injury or surgery were the exclusion criteria. Magnetic resonance imaging was used to describe the ALL injury. The association of ALL injury with other variables related to the injury and the patients background features was examined.nnnRESULTSnForty-eight patients (49 knees) were included. The mean age of the patients was 32.3 ± 10.6xa0years. High-energy trauma was the mechanism of dislocation in 28 (57.1%) knees. Thirty-one knees (63.3%) were classified as KD type IV. Forty-five (91.8%) knees had a complete ALL injury, and 3 (6.1%) knees had incomplete ALL injury. Forty (81.6%) knees had a complete ALL injury at the proximal fibers of the ALL, while 23 (46.9%) knees had complete distal ALL injury. None of the 46 (93.9%) knees with lateral collateral ligament injury had normal proximal ALL fibers (Pxa0=xa0.012). Injury to the distal fibers of the ALL, as well as overall ALL injury, was not associated with any other variables (P > .05). Moreover, all patients with associated tibial plateau fractures (9; 18.4%) had abnormality of the proximal fibers of the ALL (Pxa0= .033).nnnCONCLUSIONSnALL injury is highly prevalent among dislocated knees. Most of the injuries are of high grade and involve the proximal, suprameniscal, fibers of the ligament.nnnLEVEL OF EVIDENCEnLevel IV, retrospective case series with no comparison group.

The drill wobble effect: oversizing the femoral tunnel during ACL reconstruction

ABSTRACT Objectives: In ACL reconstruction, autologous tendon graft can be attached to the femur, within a boney tunnel, using an Endobutton device. The ultimate aim being to achieve biological fixation and incorporation into the bone. Accurate bone tunnel diameter to match the tendon graft is vital to biologic incorporation and strength. The common technique of in sequence passing a guide wire, a cannulated 4.5 mm Endobutton drill, then a cannulated femoral socket drill causes the guidewire to lose cortical fixation and stability before the femoral socket drill is passed. The Objective of this study is to analyze this common technique of femoral socket creation and determine if it results in unintentionally oversizing the femoral socket due to femoral socket drill-wobble over a destabilised guide wire. Methods: 12 cadaveric femoral pairs equally divided between two groups underwent femoral socket creation in one of the two following sequences. Group 1: Guidewire, 4.5 mm endobutton drill, 8 mm femoral socket drill. Group 2: Guidewire, 8 mm femoral socket drill, 4.5 mm endobutton drill. The created femoral tunnels apertures and calibres were measured and then compared for accuracy between the two groups. Results: Passing the 4.5 mm drill before the 8 mm socket drill results in oversized tunnel apertures and calibres when compared to passing an 8 mm socket drill after the 4.5 mm drill has been passed (p<0.0001). Conclusion: To most precisely create an 8 mm femoral socket in ACL reconstruction, the 8 mm femoral socket reamer followed by the 4.5 mm should be passed over the guide wire to prevent guide wire destabilization and drill-wobble.

Anatomic Single-Incision Repair of Distal Biceps Tendon Ruptures Using Flexible Reamers

Distal biceps tendon ruptures are treated operatively in active healthy individuals. Treatment consists of either single- or double-incision techniques, each with its own set of advantages and complications. The double incision was traditionally preferred for a more anatomic reattachment of the distal biceps tendon, but there has been renewed interest in the single-incision anterior approach given its lower risk for heterotopic ossification. However, current single-incision techniques cannot achieve anatomic reconstruction of the distal biceps because of a restricted operational angle with standard rigid instruments. The purpose of this study was to introduce a single-incision technique using flexible instrumentation, flexible guide pins, and flexible reamers that allows for an insertion point that better approximates the anatomic footprint of the distal biceps on the tuberosity. This offers the theoretical advantage of restoring forearm supination mechanics, while still maintaining the benefits of a single limited anterior exposure.

A Prospective Evaluation of Femoral Tunnel Placement for Anatomic Anterior Cruciate Ligament Reconstruction Using 3-Dimensional Magnetic Resonance Imaging

Background: The recent emphasis on anatomic reconstruction of the anterior cruciate ligament (ACL) is well supported by clinical and biomechanical research. Unfortunately, the location of the native femoral footprint can be difficult to see at the time of surgery, and the accuracy of current techniques to perform anatomic reconstruction is unclear. Purpose: To use 3-dimensional magnetic resonance imaging (3D MRI) to prospectively evaluate patients with torn ACLs before and after reconstruction and thereby assess the accuracy of graft position on the femoral condyle. Study Design: Cohort study; Level of evidence, 3. Methods: Forty-one patients with unilateral ACL tears were recruited into the study. Each patient underwent 3D MRI of both the injured and uninjured knees before surgery. The contralateral (uninjured) knee was used to define the patient’s native footprint. Patients then underwent ACL reconstruction, and the injured knee underwent reimaging after surgery. The location and percentage overlap of the reconstructed femoral footprint were compared with the patient’s native footprint. Results: The center of the native ACL femoral footprint was a mean 12.0 ± 2.6 mm distal and 9.3 ± 2.2 mm anterior to the apex of the deep cartilage. The position of the reconstructed graft was significantly different, with a mean distance of 10.8 ± 2.2 mm distal (P = .02) and 8.0 ± 2.3 mm anterior (P = .01). The mean distance between the center of the graft and the center of the native ACL femoral footprint (error distance) was 3.6 ± 2.6 mm. Comparing error distances among the 4 surgeons demonstrated no significant difference (P = .10). On average, 67% of the graft overlapped within the native ACL femoral footprint. Conclusion: Despite contemporary techniques and a concerted effort to perform anatomic ACL reconstruction by 4 experienced sports orthopaedic surgeons, the position of the femoral footprint was significantly different between the native and reconstructed ACLs. Furthermore, each surgeon used a different technique, but all had comparable errors in their tunnel placements.

Dynamic Valgus Instability of the Knee due to Chronic Medial CollateralLigament Laxity as a Cause of Recurrent Patella Dislocation

Recurrent patella dislocation can be caused by bony abnormalities, such as patella alta, increased tibial tubercle lateralization, trochlea dysplasia, excessive femoral neck anteversion and external tibial torsion. It can also be caused by soft tissue abnormalities such as a ruptured medial patellofemoral ligament (MPFL) or a weak vastus medialis obliquus. It has been reported in the literature that acute lateral dislocation of the patella can be associated with proximal injury to the medial collateral ligament (MCL). nThis article reports the case of a 26-year-old male pro footballer who had recurrent patella dislocation related to previous injury to his MPFL and worsened by dynamic valgus knee instability due to chronic MCL insufficiency.