W. Dilworth Cannon

The incidence of healing in arthroscopic meniscal repairs in anterior cruciate ligament-reconstructed knees versus stable knees

In this study, follow-up data was obtained in 90 of 117 consecutive meniscal repairs. In Group I, there were 68 meniscal repairs in conjunction with anterior cruciate ligament reconstruction, and in Group II, 22 isolated repairs in anterior cruciate ligament stable knees. Men iscal healing was assessed using the criteria estab lished by Henning, by either arthroscopy or arthrogra phy, at a mean of 7 months for isolated repairs and a mean of 10 months for repairs done in conjunction with anterior cruciate ligament reconstruction. Average time from injury to surgery was 19 months in Group I pa tients, and 14 months in Group II patients. The overall rate of successful healing was 82%. Group I repairs were successful 93% of the time compared to a 50% success rate in Group II (P < 0.00005). Lateral meniscal repairs fared better than medial repairs in both groups. Although a smaller rim width yielded better overall healing, there was no difference in the mean rim width of the two groups. Patients with anterior cruciate liga ment reconstruction did better than those with isolated meniscal repair, regardless of tear length. Older pa tients had better healing than younger ones. Overall, acute repairs were more successful than repairs of chronic tears. Even so, the chronic Group I patients had a 91 % successful healing rate.

An autologous cartilage tissue implant NeoCart for treatment of grade III chondral injury to the distal femur: prospective clinical safety trial at 2 years.

Background The healing potential of damaged articular cartilage is limited. The NeoCart is a tissue-engineered collagen matrix seeded with autogenous chondrocytes designed for the repair of hyaline articular cartilage. Hypothesis The NeoCart implant is well tolerated in the human knee. Study Design Case series; Level of evidence, 4. Methods Eight patients (treatment group) with full-thickness cartilage injury were treated with the NeoCart and evaluated prospectively. Autogenous chondrocytes provided by arthroscopic biopsy were seeded into a 3-dimensional type I collagen scaffold. The seeded scaffold was subjected to a tissue-engineering protocol including treatment with a bioreactor. Implantation of the prepared cartilage tissue patch was performed via miniarthrotomy and secured with a collagen bioadhesive. Evaluations through 24 months postoperatively included the subjective International Knee Documentation Committee questionnaire, visual analog scale, range of motion, and cartilage-sensitive magnetic resonance imaging (MRI), including quantitative T2 mapping. Results Pain scores after NeoCart implantation were significantly lower than baseline at 12 and 24 months after the procedure (P < .05). Improved function and motion were also noted at 24 months. Six patients had 67% to 100% defect fill at 24 months with MRI evaluation. One patient had moderate (33%-66%) defect fill, and another patient had poor (less than 33%) defect fill. Partial stratification of T2 values was observed for 2 patients at 12 months and 4 patients at 24 months. No patients experienced arthrofibrosis or implant hypertrophy. Conclusion Pain was significantly reduced 12 and 24 months after NeoCart treatment. Trends toward improved function and motion were observed 24 months after implantation. The MRI indicated implant stability and peripheral integration, defect fill without overgrowth, progressive maturation, and more organized cartilage formation.

Elongation of Arthroscopically Tied Knots

It has been postulated that some arthroscopic shoulder stabilization failures may be due to knot slippage. In an effort to improve arthroscopic technique, we performed tensile testing on four arthroscopically tied knots with two commonly used suture materials. Handtied square knots served as controls. Sutures of No. 1 Maxon and No. 1 Ticron were used. Four types of sliding knot configurations were tested: the overhand loop, the Duncan loop, the Roeder knot, and the Snyder knot. Knots were tied via a knot pusher, and testing was performed in a normal saline-filled thermoplastic cham ber. Knots were tied around two rings connected to a Bionix 858 materials testing apparatus. The knots were tested under conditions of cyclic loading and loading to failure. Results of the testing revealed that the most important factor in knot security was the type of suture material, although there were differences with the type of knot. With the Maxon suture, there was significantly decreased ultimate failure load of all of the arthroscopi cally tied knots compared with handtied square knots. Knots tied with Ticron were similar in strength for both arthroscopically and handtied groups. The surgeon who chooses a monofilament absorbable suture should be aware that a high percentage of knots fail under low load cyclic testing, and that all of these knots were inferior to handtied square knot controls in testing to failure.

Instrumented testing of functional knee braces

The ability of seven functional knee braces to control anterior tibial displacement in three severely lax ACL deficient knees using two instrumented testing devices was studied. Some braces were statistically shown to be much better in this regard than others, but not all data obtained was statistically significant. This material should aid one in determining which braces offer the greatest degree of control of anterior tibial displacement in patients with ACL insufficiency.

Improving residency training in arthroscopic knee surgery with use of a virtual-reality simulator: A randomized blinded study

BACKGROUND There is a paucity of articles in the surgical literature demonstrating transfer validity (transfer of training). The purpose of this study was to assess whether skills learned on the ArthroSim virtual-reality arthroscopic knee simulator transferred to greater skill levels in the operating room. METHODS Postgraduate year-3 orthopaedic residents were randomized into simulator-trained and control groups at seven academic institutions. The experimental group trained on the simulator, performing a knee diagnostic arthroscopy procedure to a predetermined proficiency level based on the average proficiency of five community-based orthopaedic surgeons performing the same procedure on the simulator. The residents in the control group continued their institution-specific orthopaedic education and training. Both groups then performed a diagnostic knee arthroscopy procedure on a live patient. Video recordings of the arthroscopic surgery were analyzed by five pairs of expert arthroscopic surgeons blinded to the identity of the residents. A proprietary global rating scale and a procedural checklist, which included visualization and probing scales, were used for rating. RESULTS Forty-eight (89%) of the fifty-four postgraduate year-3 residents from seven academic institutions completed the study. The simulator-trained group averaged eleven hours of training on the simulator to reach proficiency. The simulator-trained group performed significantly better when rated according to our procedural checklist (p = 0.031), including probing skills (p = 0.016) but not visualization skills (p = 0.34), compared with the control group. The procedural checklist weighted probing skills double the weight of visualization skills. The global rating scale failed to reach significance (p = 0.061) because of one extreme outlier. The duration of the procedure was not significant. This lack of a significant difference seemed to be related to the fact that residents in the control group were less thorough, which shortened their time to completion of the arthroscopic procedure. CONCLUSIONS We have demonstrated transfer validity (transfer of training) that residents trained to proficiency on a high-fidelity realistic virtual-reality arthroscopic knee simulator showed a greater skill level in the operating room compared with the control group. CLINICAL RELEVANCE We believe that the results of our study will stimulate residency program directors to incorporate surgical simulation into the core curriculum of their residency programs.

Evaluation of skill level between trainees and community orthopaedic surgeons using a virtual reality arthroscopic knee simulator.

BACKGROUND Several virtual reality simulators have been developed to assist orthopaedic surgeons in acquiring the skills necessary to perform arthroscopic surgery. The purpose of this study was to assess the construct validity of the ArthroSim virtual reality arthroscopy simulator by evaluating whether skills acquired through increased experience in the operating room lead to improved performance on the simulator. METHODS Using the simulator, six postgraduate year-1 orthopaedic residents were compared with six postgraduate year-5 residents and with six community-based orthopaedic surgeons when performing diagnostic arthroscopy. The time to perform the procedure was recorded. To ensure that subjects did not sacrifice the quality of the procedure to complete the task in a shorter time, the simulator was programmed to provide a completeness score that indicated whether the surgeon accurately performed all of the steps of diagnostic arthroscopy in the correct sequence. RESULTS The mean time to perform the procedure by each group was 610 seconds for community-based orthopaedic surgeons, 745 seconds for postgraduate year-5 residents, and 1028 seconds for postgraduate year-1 residents. Both the postgraduate year-5 residents and the community-based orthopaedic surgeons performed the procedure in significantly less time (p = 0.006) than the postgraduate year-1 residents. There was a trend toward significance (p = 0.055) in time to complete the procedure when the postgraduate year-5 residents were compared with the community-based orthopaedic surgeons. The mean level of completeness as assigned by the simulator for each group was 85% for the community-based orthopaedic surgeons, 79% for the postgraduate year-5 residents, and 71% for the postgraduate year-1 residents. As expected, these differences were not significant, indicating that the three groups had achieved an acceptable level of consistency in their performance of the procedure. CONCLUSIONS Higher levels of surgeon experience resulted in improved efficiency when performing diagnostic knee arthroscopy on the simulator. Further validation studies utilizing the simulator are currently under way and the additional simulated tasks of arthroscopic meniscectomy, meniscal repair, microfracture, and loose body removal are being developed.

Arthrometric Evaluation of Posterior Cruciate Ligament Injuries

We reviewed the clinical examinations and knee arthrometry evaluations of 40 patients: 10 with posterior cruciate ligament injuries, 10 with combination anterior and posterior cruciate ligament injuries, 10 with anterior cruciate ligament injuries alone, and 10 with no history of knee injury. Using a 3-mm side-to-side difference as the minimal limit for detection of posterior cruciate ligament injury, the sensitivity of the arthrometer at 40 pounds of posterior force was 90%, the specificity was 100%, the predictive value of a positive test was 100%, and the predictive value of a negative test was 91%. When total anterior-posterior translation was assessed, the sensitivity was 100%, the specificity was 85%, the predictive value of a positive test was 87%, and the predictive value of a negative test was 100%. The overall accuracy of arthrometry for detection of posterior cruciate ligament injury was 96% for 40 pounds of posterior force and 94% for total anterior-posterior translation at 40 pounds. Grade 1 posterior cruciate ligament injuries had significantly greater arthrometric posterior translation compared with grade 0 (normal) knees. Regression analysis showed arthrometric laxity measurements correlated well with the clinical grade of the posterior drawer test. Finally, the accuracy of the arthrometer was not affected by concomitant anterior cruciate ligament injury.

SYMPOSIUM: The Emerging Impact of the Information Age on Orthopaedic Surgery*: Development of a Virtual Reality Arthroscopic Knee Simulator

The virtual reality arthroscopic knee simulator (VR-AKS) consists of a computer platform, a video display, and two force-feedback (haptic) interfaces which also monitor the position of the instruments in the users hands. The forces that the user would normally apply to the lower limb during arthroscopy are directed through an instrumented surrogate leg. Proprietary software furnishes the mathematical representation of the physical world and replicates the visual, mechanical, and behavioral aspects of the knee while task-oriented programs monitor and record specific areas of user performance. A prototype has demonstrated the feasibility of the system and work on the first, fully functional simulator will begin soon.

The role of arthroscopic debridement after anterior cruciate ligament reconstruction

This retrospective study included 55 patients who had prior anterior cruciate ligament (ACL) reconstruction; 30 made up the experimental group who had arthroscopic debridement of impinging soft tissue and 25, who did not have a second-look arthroscopy, were used as controls. Impinging tissue was not necessarily the primary reason for arthroscopy in the experimental group. Only nine patients (30%) were debrided solely because of anterior symptoms suggestive of soft tissue impingement; 16 (53%) underwent arthroscopy primarily to assess meniscal repairs; five (17%) were done in conjunction with hardware removal. Both groups were evaluated for pain, crepitation, and anterior laxity at three specific times. Debridement reduced crepitation from 35% to 8% in patients with moderate crepitus, and from 50% to 38% in patients with mild symptoms. The percentage of patients without crepitation increased from 15% to 54% by final follow-up. Predebridement, 14% of patients had moderate pain, and 53% mild pain. By final follow-up, 38% had mild pain and 62% were pain free. Patients benefitted from debridement regardless of method of ACL reconstruction. Arthroscopic debridement did not increase anterior knee translation. Both groups gained extension and had improved activity levels with the passage of time from ACL surgery.

AIDS and arthroscopic surgery.

There are an estimated 8 to 10 million people worldwide infected with human immunodeficiency virus (HIV). The true extent of infection in the population is unknown, and many are unaware of their HIV status. Arthroscopic and arthroscopically assisted surgery is less invasive and bloody than other orthopaedic procedures, and seemingly less hazardous to surgeons. Nevertheless, the potential for exposure exists. Arthroscopic surgeons routinely experience gown, face-mask and shoe-cover saturation from the splashing of blood-tainted irrigation fluid. Glove perforations by needles, sharps, and bone fragments can occur. Bone and tissue allografts pose risks to both surgeon and patient, as HIV has been recovered from fresh, frozen and freeze-dried specimens. The process of cleaning and disinfecting arthroscopes adequately can damage these expensive devices. This article addresses the safeguards that arthroscopic surgeons should take to prevent exposure to HIV. Effective sterilizing and disinfecting techniques for arthroscopes are also discussed.