Intra-articular Distance Research Articles

No-Tunnel Anterior Cruciate Ligament Reconstruction: The Transtibial All-Inside Technique

The purpose of this technical note is to describe the transtibial all-inside anterior cruciate ligament (ACL) reconstruction technique. This technique combines the advantages of previously described but technically demanding all-inside ACL reconstruction techniques with the ease and familiarity of transtibial guide pin placement. The all-inside technique uses bone sockets as opposed to bone tunnels in both the femur and the tibia and represents a “no-tunnel” technique. When performed with allograft tissue, the method requires only arthroscopic portals and percutaneous guide pin passage. In such cases, this represents a “no-incision” ACL reconstruction. The technique requires the use of a Dual Retrocutter (Arthrex, Naples, FL). This cannulated drill is placed via the anteromedial arthroscopic portal and threads onto a transtibial, percutaneous, reverse-threaded guide pin. Because the drill is assembled arthroscopically (within the joint), a skin incision is not required. The Dual Retrocutter is capable of retrograde and antegrade drilling. Thus, a single Dual Retrocutter achieves transtibial drilling of both tibial and femoral bone sockets. The transtibial all-inside technique may be performed with the use of any ACL graft option. Graft diameter should equal socket diameter. To prevent the graft from “bottoming-out” during tensioning and fixation, graft length must be less than the sum of combined femoral plus tibial socket lengths plus ACL intra-articular distance. During the learning curve, surgeons may choose to wait until the sockets have been prepared, so that graft length need not be estimated. If the graft is prepared before arthroscopic surgery is performed, a 79-mm graft length could be recommended as ideal. To prepare for graft passage, both femoral and tibial graft passing suture loops must be brought out the anteromedial arthroscopic portal without soft tissue interposition between or within the loops. To prepare for graft fixation, a nitinol wire must be brought into the joint via the transtibial, percutaneous guide pin tract for the purpose of guiding the introduction of a cannulated Retroscrewdriver. All of these goals may be accomplished in a single pass. The graft is fixed with femoral and tibial Retroscrews. Backup fixation is optional and may be achieved by tying sutures over small, percutaneously placed cortical buttons. Advantages of this technique may result from “anatomic” graft fixation at the levels of the femoral and tibial joint lines and from retrograde screw fixation, which may eliminate interference screw divergence and increase graft tension when the retrograde screw is advanced. Additionally, because this technique minimizes skin incisions and eliminates open bone tunnels, patients may experience decreased pain, more rapid return to function, and improved cosmesis.

Kinematics of the human mandible for different head postures.

The influence of head posture on movement paths of the incisal point (IP) and of the mandibular condyles during free open-close movements was studied. Ten persons, without craniomandibular or cervical spine disorders, participated in the study. Open close mandibular movements were recorded with the head in five postures, viz., natural head posture, forward head posture, military posture, and lateroflexion to the right and to the left side, using the Oral Kinesiologic Analysis System (OKAS-3D). This study showed that in a military head posture, the opening movement path of the incisal point is shifted anteriorly relative to the path in a natural head posture. In a forward head posture, the movement path is shifted posteriorly whereas during lateroflexion, it deviates to the side the head has moved to. Moreover, the intra-articular distance in the temporomandibular joint during closing is smaller with the head in military posture and greater in forward head posture, as compared to the natural head posture. During lateroflexion, the intra-articular distance on the ipsilateral side is smaller. The influence of head posture upon the kinematics of the mandible is probably a manifestation of differences in mandibular loading in the different head postures.

The intra-articular distance within the TMJ during free and loaded closing movements.

Previous studies on free opening and closing movements of the mandible have demonstrated that the opening movement traces of the condylar kinematic center (i.e., the condylar point for which the protrusive and the opening movement traces coincide) lie closer to the articular eminence than the closing traces. This indicates the presence of an intra-articular distance within the joint during free closing. Since the mandible behaves like a class III biomechanical lever, a counteracting mechanical load on the mandible during closing will press the condyle-disc complex against the articular eminence. Therefore, in this study the hypothesis was tested that the difference between opening and closing movement traces of the kinematic center is reduced when the closing movements are counteracted by a mechanical load. From 10 healthy participants, 20-second movement recordings were obtained by a six-degrees-of-freedom opto-electronic jaw movement recording system (OKAS-3D) for three types of movements: (1) free opening and closing movements, (2) free opening and loaded closing movements (i.e., the participants closed against a small or high manually applied downward-directed force to the chin), and (3) gum chewing. Off-line, the opening and closing movement traces of the kinematic center were reconstructed, and the average difference between the traces (the intra-articular distance) was calculated. The average intraarticular distance was significantly smaller during loaded closing than during free closing, whereas no significant differences were found in the intra-articular distances between the loaded situations of low and high manual loading and contralateral chewing (ANOVA and post hoc Bonferroni multiple comparisons of means test, p<0.005). In conclusion, loading of the mandible during closing movements reduces the intra-articular distance within the temporomandibular joint.

Avoiding Graft-Tunnel Mismatch in Endoscopic Anterior Cruciate Ligament Reconstruction: A New Technique

Summary: A common problem encountered in endoscopic anterior cruciate ligament reconstruction is graft-tunnel mismatch. A technique not previously described in the literature is illustrated. This technique provides direct measurement of the tibial tunnel length plus the intra-articular distance. This allows direct calculation of the length of the femoral tunnel necessary to avoid a graft-tunnel mismatch. This technique has been used very effectively in our institution with excellent, reproducible results. Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 15, No 3 (April), 1999: pp 338–340

All-inside anterior cruciate ligament reconstruction using semitendinosus tendon and soft threaded biodegradable interference screw fixation.

A modification of anterior cruciate ligament (ACL) reconstruction using a minimally invasive and endoscopic all-inside technique is presented. Both the femoral and tibial socket are approached through the joint so that there is no open tibial tunnel, which otherwise often causes significant pain and discomfort during early rehabilitation. The autologous semitendinosus tendon is harvested with a bone plug attached to its tibial insertion. The triple-stranded semitendinosus tendon is looped around the adjacent bone plug and fixed at the original tibial attachment site of the ACL using a soft threaded biodegradable poly-(D,L-lactide) interference screw. The screw is inserted endoscopically in an inside-out direction. In the femoral socket the graft is fixed without a bone plug directly to the tunnel wall using the biodegradable screw. The free part of the graft is thus not longer than the intra-articular distance, which may increase stiffness of the construct.

Cruciate ligament graft intra-articular distances.

Although the length of the anterior and posterior cruciate ligaments have been well characterized in the literature, we are not aware of any studies of the actual length of grafts used in reconstruction of these ligaments. We dissected and measured these distances for 18 cadaver knees of varying size and sex. The precise location of ideal guide pin placement was located based on current recommendations, and the intra-articular graft length was measured with a micrometer by two separate observers. We found that the average intra-articular graft length for the anterior cruciate ligament is 23.56 mm (SD, 0.98 mm), the posterior cruciate ligament is 30.72 mm (SD, 2.61 mm) and the patella tendon graft intertendinous distance is 43.33 mm (SD, 4.21 mm) We conclude that the intra-articular distance for cruciate ligament grafts is less than published values for the ligaments themselves, and that the patella tendon graft is of adequate length to be used for reconstruction of these ligaments.