Intramedullary screw fixation of Jones fractures: a biomechanical study.

The management of proximal fifth metatarsal ("Jones") fractures in athletes has become increasingly more aggressive, despite a lack of biomechanical data in the literature. A cadaver biomechanical study was conducted to evaluate the strength of intramedullary fixation of simulated Jones fractures loaded to failure via three-point bending on a Materials Testing System machine. In a series of eight intact fifth metatarsal control specimens, the force to failure (fracture) was measured for comparison with repaired specimens. Acute fractures were simulated in 10 pairs of feet via osteotomy at the typical fracture location and were fixed with either a 4.5-mm malleolar screw or a 4.5-mm partially threaded, cancellous, cannulated screw, both placed using conventional intramedullary techniques. Force at initial displacement averaged 73.9 N (SD, 64.7 N) for the malleolar screws and 72.5 N (SD, 42.3 N) for the cannulated screws. Force at complete displacement averaged 519.3 N (SD, 226.2 N) for the malleolar screws and 608.4 N (SD, 179.7 N) for the cannulated screws. The force to failure of the intact specimens was significantly greater than the initial and complete forces to failure for the fixed specimens (P < 0.05, independent measures analysis of variance). There was no statistical difference between the average forces at initial displacement or at complete displacement in the fixed metatarsal specimens for the two different types of screws, but the forces at complete displacement for each screw type were significantly greater than the forces at initial displacement (P < 0.05). On the basis of literature review and data generated from this study, it is apparent that the forces necessary to cause displacement of the stabilized Jones fracture are above what would be transmitted within the lateral midfoot during normal weightbearing. The choice of screw and intramedullary technique of fixation is a matter of surgeon preference, because the choice of screw makes no biomechanical difference.

When tumors pose as sports injuries.

In active patients, benign tumors such as osteoid osteoma, aneurysmal bone cyst, and chondroblastoma can masquerade as common sports-related conditions like muscle strains or tendinitis. Sometimes musculoskeletal symptoms can result from a cyst or tumor in another organ system. Four case studies show that the physician should have a high index of suspicion when patients do not respond as expected to initial conservative treatment. In such instances, appropriate referrals or imaging studies must be considered. Beyond plain radiographs, MRI or CT may be helpful if warranted by clinical and radiographic findings. Specific treatment of benign bone tumors is individualized, but commonly includes curettage and bone grafting.

The fate of intra-articular debris following arthroscopic anterior cruciate ligament reconstruction.

The debris generated during arthroscopic anterior cruciate ligament (ACL) reconstruction may be seen on postoperative radiographs. The purpose of this study was to evaluate the incidence, effects, and natural history of intra-articular debris following ACL reconstruction. This retrospective review included 99 ACL reconstructed knees in 96 patients. Radiographically visible debris was present in 63% of knees (bone in 59% and metal in 4%), and 37% of knees had no visible debris. Bone was most commonly seen in the posterior compartment (95%), and metal within the intercondylar notch. There were no differences in the incidence of debris between reaming techniques, single and dual incision techniques, or between graft types. Metal debris was always associated with retrograde reaming. Complete disappearance of bone debris was noted in 71% (3 to 6 months). Of the 25% of knees that showed persistent bone debris, in 79% it had decreased in size. There was no change in the appearance of metal debris (4%). No patient experienced mechanical symptoms directly related to debris. No secondary surgeries for debridement of debris or loose body removal were required. Bone debris produced during arthroscopic ACL reconstruction appears clinically benign, and is likely to disappear by 6 months. Long-term effects are unknown. Metal debris is persistent, but not problematic over the short-term.

Magnetic resonance imaging assessment of the rotator cuff: is it really accurate?

Magnetic resonance imaging (MRI) is used increasingly for evaluating the rotator cuff. This study of 39 shoulders (38 patients) compared the accuracy of MRI interpretation of rotator cuff integrity by a group of community hospital radiologists (clinical community scenario, CCS) with that of a musculoskeletal radiologist (experienced specialist scenario, ESS), relative to arthroscopy. For the CCS subgroup, the sensitivity, specificity, positive predictive value (PV), negative PV, and accuracy for partial tears were: 0%, 68%, 0%, 82%, and 59%, respectively; for complete tears: 56%, 73%, 36%, 86%, and 69%, respectively; and for all tears combined: 85%, 52%, 50%, 87%, and 64%, respectively. For the ESS subgroup, the respective values for partial tears were: 20%, 88%, 20%, 88%, and 79%, respectively; for complete tears: 78%, 83%, 58%, 92%, and 82%, respectively; and for all tears: 71%, 71%, 59%, 81%, and 71%, respectively. We concluded that MRI assessment of the rotator cuff was not accurate relative to arthroscopy. MRI was most helpful if the result was negative, and MRI diagnosis of partial tear was of little value. Considering the high cost of shoulder MRI, this study has significant implications for the evaluation of patients with possible rotator cuff pathology.

Infrapatellar contracture syndrome. Diagnosis, treatment, and long-term followup.

Infrapatellar contracture syndrome is an uncommon but recalcitrant cause of reduced range of motion after knee surgery or injury. The results and conclusions presented here are based on a retrospective clinical study evaluating the long-term outcome in 75 patients who developed infrapatellar contracture syndrome. These 75 patients (76 knees) were evaluated at an average followup of 53 months after the index (inciting) procedure or injury. Comparing subgroups within the study population, factors that correlated with poorer results or more severe infrapatellar contracture syndrome were found to be acute anterior cruciate ligament repair or reconstruction, the use of patellar tendon autograft for anterior cruciate ligament reconstruction, nonisometric graft placement, multiple surgical procedures, use of closed manipulation, and the development of patella infera. We concluded that appropriate procedures can substantially increase the range of motion in patients with infrapatellar contracture syndrome. However, residual functional morbidity persists in many patients, and the outcome, as determined by subjective knee function scores, is only fair. The natural history of an anterior cruciate ligament-deficient knee appears to be more benign than the natural history of a knee that develops infrapatellar contracture syndrome.

Carpal collapse and Sudeck's atrophy.

Acute posttraumatic (Sudeck's) atrophy of the upper extremity is well known. The symptoms and signs are out of proportion to what is to be expected from the inciting event. Typically, bone atrophy is characterized by a focal, patchy, periarticular demineralization pattern, which is usually transient. Remineralization occurs after successful treatment. This report describes a typical case of the clinical syndrome after a wrist sprain but with carpal dissolution and collapse before remineralization.

Anatomic and biomechanical analysis of the arthroscopic wafer procedure.

The ulnar impaction syndrome is a common clinical entity that is most often associated with positive ulnar variance and is characterized by triangular fibrocartilage complex (TFCC), lunate, and/or distal ulnar pathology. Traditional treatment for symptomatic ulnar impaction syndrome has been conservative; however, in cases refractory to nonoperative management, formal ulnar shortening has been successful in long-term clinical series. Recently, arthroscopic ulnar shortening, the "arthroscopic wafer procedure" (AWP) (debridement of the perforated TFCC margins and limited ulnar head resection using a motorized burr) has become an option to treat this clinical syndrome. In an attempt to evaluate the biomechanical efficacy of the AWP, an experimental study was undertaken using nine ulnar positive cadaver forearms. Each specimen was evaluated biomechanically using axial load cells and pressure-sensitive film to evaluate the effect of serial resection of the TFCC and distal ulna on axial load and ulnar carpal pressures. The results of this experimental study revealed a statistically significant unloading of the ulnar aspect of the wrist after excision of the centrum of the TFCC and resection of the radial two-thirds width of the ulnar head, to a depth of subchondral bone resection. Furthermore, additional bony resection tended to correlate favorably with the stage of TFCC pathology noted, i.e., the more advanced the stage, the more resection necessary to unload the ulnar aspect of the wrist. Based on this biomechanical study, a limited clinical series has been initiated with early favorable results. The AWP biomechanically unloads the ulnar carpal complex, and therefore has a theoretical potential of relieving the symptoms of the ulnar impaction syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Rehabilitation following knee surgery. Recommendations.

Satisfactory results following knee surgery can be obtained only through the combined efforts of the surgeon, patient and therapist. A rehabilitative plan is based upon consideration of the effects of disuse and immobility on musculoskeletal tissues, and knowledge of the healing requirements following injury and specific surgical procedures. A balance must be made between simultaneous demands for protection against undue stress to facilitate healing and the need for stress to retard atrophy of musculoskeletal tissue. A thorough review of these concepts forms the basis for a rational approach to rehabilitation after specific surgical procedures. The phasic approach to knee rehabilitation is based upon progression in a logical fashion through the chronology of immobility, range of motion, progressive weight bearing and strengthening exercises. The latter category can be subdivided into its own progression from isometrics, isotonics, functional exercises through isokinetics. The ultimate goal and final phase is a safe return to full activity. By integrating a thorough knowledge of the healing parameters of musculoskeletal tissues and the simultaneous coexisting needs for protection and controlled stress, specific rehabilitative programmes can then be designed for the most common surgical procedures including: anterior and posterior cruciate ligament reconstruction, meniscal repair and meniscectomy, lateral release and hyaline cartilage procedures.

[Arthroscopic surgery: meniscus refixation and meniscus healing]. / Arthroskopische Chirurgie: Meniskusrefixation und Meniskusheilung.

The stabilizing function of the meniscus and the negative effect of a complete or partial meniscectomy have been demonstrated in many studies. On the other hand, it has also been shown that meniscus tears in certain locations can heal very well. The prerequisite is that the torn meniscus can be revascularized from the capsule. Revascularization can be achieved by stimulating the formation of new vessels, but also by the build-up of collagen after induction of fibrochondrocytes and fibroblasts. The requirements for meniscus reconstruction are: careful preparation of the tear, exact repositioning, and precise placement of the sutures. The additional activation of regenerating processes is promoted by using a fibrin clot. In this study, 54 patients underwent meniscus repair, but the results in this group that also received a fibrin clot are not included. In the case of longitudinal-vertical tears of the meniscus inside the 3-mm zone margin, it was decided that the procedure was indicated when tears longer than 1.5 cm were concerned. The inside-out technique was used. Subjective and objective examination of 52 patients showed that the clinical results were good to very good in 92%.