Treatment of massive rotator cuff tears can be challenging. Previous studies with irreparable rotator cuff tears showed good clinical results of tendon healing with the arthroscopic insertion of a protective biodegradable spacer balloon filled with saline solution between the repaired tendon and the acromion [1,2], but so far no scientific evidence has showed how the device alters pressures over the repaired tendon. This biomechanical study investigated the effects of a spacer inserted in the subacromial space on pressures over the repaired rotator cuff tendon in passive motion cycles typical for post-operative rehabilitation routines.

Six human cadaveric shoulders were prepared with the humerus cut 15cm below the joint and embedded in a pot, while the scapula fixed at three points on a plate. A rotator cuff tear was simulated and repaired using a suture anchor and a Mason-Allen suture. The specimens were then mounted on a custom-made pneumatic testing rig to induce passive motion cycles of adduction-abduction (90–0°) and flexion-extension (0–40°) with constant glenohumeral and superior loads and tension is exerted on the supraspinatus tendon with weights. A pressure sensor was placed between the supraspinatus tendon and the acromion. After pressure measurements for 15 cycles of each motion type, the InSpace balloon (OrthoSpace, Inc, Israel) was inserted and the specimens tested and pressure measured again for 15 cycles. Statistically significant changes in peak pressures were then measured before and after balloon.

Peak pressures were measured near 90 degrees abduction. No statistical differences were observed for internal-external rotation before and after balloon-shaped subacromial spacer was inserted. Mean pressures in abduction-adduction were significantly reduced from 121.7 ± 9.5 MPa to 51.5 ± 1.2 MPa. Peak pressures after repair were 1171.3 ± 99.5 MPa and 1749.6 ± 80.7 MPa in flexion-extension and abduction-adduction motion, respectively, and significantly decreased to 468.7 ± 16.0 MPa and 535.1 ± 27.6 MPa after spacer insertion (p<0.0001).

The use of the spacer above the repaired tendon reduced peak pressures and distributed them more widely over the sensor during both abduction-adduction and flexion-extension motions and therefore can reduce the stress on the rotator cuff repair. The InSpace system may reduce the pressure on the repaired tendon, thus potentially protecting the repair. Further studies to investigate this phenomenon are warranted, in particular relating these changes to shoulder kinematics following tear repair and spacer insertion.

Background: The embryology of the cruciate ligaments of the knee had received scant attention in the orthopaedic and embryologic literature. Understanding the embryonic development of the blood supply to criciate ligaments (CL) may help to comprehend the mechanisms of pathology leading to failure of these structures and of the revascularization process after reconstruction injured of cruciate ligaments or implantation of grafts.

Aim: To describe the anatomy and spatial relationships of the cruciate ligaments and their blood supply in the developing fetus.

Method: Knees from one leg of 48 normal human embryos from abortion material were examined, gestational age varying from early as the 8^th week and up to the 20^th week. Microscopic semi serial consequent sections of the knees were examined under light microscope and spatial changes within the cruciate ligaments were noted. The contra-lateral knees of some of the embryos were dissected to confirm the three dimensional picture. This gave us the possibility to follow the developmental changes of the spatial orientation of the cruciate ligaments and the blood vessels within them.

Results: The anterior and posterior cruciate ligaments are formed from a single mass of cells, divided by a sinovial septum. Folds within the septum partially divide the ligaments into bundles and carry within them the vasculature needed to sustain the ligaments. We show that the blood supply of the growing CL arises from the middle genicular artery and enters the ligaments from the poster-superiolateral corner (P.S.L.C.) of the inter-condylar notch, passes between the ACL and PCL and descends along he posterior aspect of the ACL.

These findings can explain why injury involving the P.S.L.C. in the adult has a worse prognosis for rehabilitation.

The importance of meniscal tears repair is discussed widely in the literature. The repair should be performed if the conditions promise some chance for healing. Due to technical difficulties many orthopaedic surgeons still prefer partial meniscectomy to meniscal repair.

We describe our techniques for meniscal repair. The described techniques could be used by any surgeon with basic skills in arthroscopic surgery. No special equipment is needed.

The basic equipment for this technique is a standard 18 gouge needle. The plastic cup of the needle is cut away in order to overcome the ridge between the plastic and the metal part of the needle, thus making the suture passage easier.

Following the arthroscopic identification of the meniscal tear and preparing the torn parts for repair, the place for the first suture is identified.

A 2–3 mm long skin incision is made. The subcutaneous tissue is bluntly developed to the capsule. The 18 gouge needle is past from outside-in in the desired point through the torn margins of the meniscus. The tip of the needle is emerged above or under the meniscal surface, depends on our decision of suture position.

1st step – Producing a loop outside the joint: Two ends of a nylon 2/0 suture are inserted through the needle into the joint cavity, and pulled out through one of the arthroscopic portals. The needle is removed. The result of this step is a nylon 2/0 suture passing through the torn parts of the meniscus with a loop outside the joint.

2nd step – Producing a double-loop inside the joint cavity: A second nylon 2/0 suture is passed through the first loop. The first suture is pulled into the joint. At this stage, both loops are inside the joint, holding each other. The free ends of the first loop are emerged through one of the arthroscopic portals, while the free ends of the second loop pass through the torn parts of the meniscus and emerge through the capsule.

3rd step – Producing the meniscal suture: A second 19 gouge needle is inserted close to the point of insertion of the first one, directed into the joint. The emerging point of this needle, on the meniscus, should be positioned according to the desired suture direction (transverse, vertical, or oblique). The tip of the needle is then directed into the “2nd” nylon loop (the “1st” nylon loop can assist at this stage). The loop is wrapped over the needle, and the 1st suture is removed.

PDS suture (1/0 or 2/0) is inserted through the needle until a 5 cm free end is positioned intra articular. The needle is removed with caution without pulling the PDS suture, leaving the

PDS free end inside the nylon loop. The nylon loop is used as a pooling tool for the PDS suture. Pulling the free end of the PDS suture out of the joint results in a PDS loop for the meniscal suture (in order to avoid iatrogenic tear of the meniscal tissue while pulling the sutures, a probe should be positioned under the PDS suture during the process). The PDS is tightened over the capsule. The technique is repeated as much as necessary for perfect repair of the meniscus.

The advantage of this method is that it does not necessitates unique equipment, but rather uses the ordinary arthroscopic tools and sutures. This method was used successfully upon large number of meniscal tears. We recommend its use routinely.