Arthroscopic decompression for impingement syndrome secondary to an unstable os acromiale.

PURPOSE: The purpose of this study was to examine cases of patients with impingement syndrome secondary to an unfused, unstable, os acromiale. TYPE OF STUDY: Retrospective case series. MATERIALS AND METHODS: Twelve consecutive patients (13 shoulders) presented with impingement symptoms in the presence of an os acromiale. The os acromiale, at the meso-acromion level, was seen on standard radiographs. The patients were all treated conservatively with rotator cuff strengthening, stretching, anti-inflammatory medications, and steroid injections. All patients underwent an impingement test with lidocaine, resulting in complete relief of their pain. After failure of the conservative management, the 12 patients (13 shoulders) underwent an extended arthroscopic subacromial decompression. The goal of the modified arthroscopic acromioplasty was resection of adequate bone to remove the mobile anterior acromial tip. In general, this consisted of more bony resection than the typical arthroscopic acromioplasty. Postoperatively, the patients began a rehabilitation program emphasizing early range of motion followed by isolated free-weight rotator cuff strengthening exercises. Five shoulders had a partial-thickness tear of the rotator cuff. Four involved less than 50% of the thickness of the rotator cuff. These 4 partial-thickness tears underwent arthroscopic rotator cuff debridement. One partial-thickness tear was greater than 50% and repair was performed with a mini-open deltoid-splitting technique. RESULTS: Results were evaluated using UCLA shoulder scoring. Preoperatively, the score averaged 17. The 3-month postoperative score was 27, and at 6 and 12 months, averaged 28. The final follow-up score averaged 31. There were 11 satisfactory results with UCLA scores >/=28. Two unsatisfactory results showed UCLA scores in the fair category. Full strength of the anterior deltoid and rotator cuff muscles was achieved in all patients by 6 months postoperatively as evaluated by manual muscle testing. Twelve of the 13 shoulders were rated by the patients as having a satisfactory result. All of the patients rated their cosmetic results as acceptable. There was no evidence of postoperative deltoid detachment. No patient developed pain at the pseudarthrosis point. CONCLUSIONS: Given the previously reported poor results with attempts at fusion of an unstable os acromiale and open complete excision of meso-acromial fragments, the authors conclude that an extended arthroscopic subacromial decompression results in a reasonable outcome for patients with impingement syndromes secondary to an unstable os acromiale.

Cost-benefit comparison: holmium laser versus electrocautery in arthroscopic acromioplasty.

This prospective study was designed to measure the costs and benefits of using a laser rather than electrocautery for soft tissue resection during arthroscopic shoulder decompression. Forty-nine shoulders with refractory Neer stage II impingement (persistent fibrosis and tendinitis) were divided into 2 groups. The composition of the 2 groups was similar with regard to sex, worker's compensation status, dominant arm involvement, duration of symptoms, and length of conservative treatment. In one group, electrocautery was used to ablate the bursa and periosteum, release the coracoacromial ligament, and maintain hemostasis. In the other group, a laser was used in place of electrocautery. Patients had been evaluated preoperatively with 2 functional scoring systems. The patients were reexamined at 1 week and at 1, 2, 3, 6, and 12 months after surgery. There were no differences between the groups with regard to functional outcome or satisfaction. There was also no difference in terms of estimated blood loss or operative time. However, there was a statistically significant difference in total hospital charges between groups, with the laser group having a 23% higher hospital bill. On the basis of these results, it is concluded that there was no medical benefit to laser-assisted arthroscopic subacromial decompression but there was an increased monetary cost.

Home based rehabilitation for anterior cruciate ligament reconstruction.

Fifty-four patients who underwent arthroscopically assisted anterior cruciate ligament reconstruction with bone-patellar tendon-bone autograft or allograft were studied prospectively to compare a postoperative home based rehabilitation program with a clinic based program. Fifty-four patients (mean age, 30 years) were assigned randomly to the home based program (27 patients) or the clinic based program (27 patients). The home based schedule featured six physical therapy visits during a 6-month postoperative study period, whereas the clinic based schedule specified 24 physical therapy visits during those 6 months. All patients entered in the study met strict selection criteria: age older than 15 years, no previous ligament repair or reconstruction, no complicating medical conditions, no collegiate or professional athletes, reconstruction at least 6 weeks after injury, and informed consent. At the 6-month followup, no significant statistical differences were found between the two groups in range of motion, thigh atrophy, anterior drawer compliance, hopping tests, Lysholm scores, or subjective health status scores. Thus, the authors conclude that in a selected group of patients who have undergone anterior cruciate ligament reconstruction, a home based postoperative rehabilitation program is feasible, safe, and effective.

Suprascapular nerve entrapment caused by supraglenoid cyst compression.

Twenty-two cases of suprascapular nerve entrapment caused by supraglenoid cyst compression were reviewed. Pain and weakness were the presenting symptoms in 14 shoulders and pain alone in 8. Twenty of the cysts were diagnosed by magnetic resonance imaging, and two were confirmed at surgical exploration. Electromyography of 20 shoulders was positive for neurologic involvement for both the infraspinatus and supraspinatus in 4 cases, for the infraspinatus only in 12, and negative in 4. Sixteen shoulders were treated by open excision, arthroscopy, or both. Superior labral lesions were diagnosed in 11 of 12 patients who underwent arthroscopy. At follow-up 10 of the patients who underwent surgery had complete resolution of symptoms, 5 had occasional pain or weakness, and 1 recurrence required a second surgery. Of six patients treated without surgery, two improved and four had no change. Supraglenoid ganglion cysts are common and can easily be diagnosed by magnetic resonance imaging. For patients with symptoms arthroscopy with repair of the superior labral lesion and either arthroscopic debridement or direct open decompression and excision of the cyst is recommended.

Joint pain and weather. A critical review of the literature.

Many people believe that weather conditions can influence joint pain, but science offers no proof. If the phenomenon were real, cause-and-effect mechanisms might provide clues that would aid joint pain treatment. Literature on the subject is sparse, conflicting, and vulnerable to bias, and further physiologic investigations are not likely to produce useful information. However, for patients who believe that weather can influence their pain, the causes may be unknown, but the effect is real.

Chronically injured posterior cruciate ligament: magnetic resonance imaging.

Magnetic resonance imaging has been said to be highly reliable for diagnosis of acute posterior cruciate ligament insufficiency. In the present study, 13 patients whose posterior cruciate ligament insufficiency had been documented by magnetic resonance imaging within 10 weeks of the acute injury were recalled for a followup examination and magnetic resonance imaging. The followup interval ranged from 5 months to 4 years. In only 23% of the cases did the posterior cruciate ligament still appear discontinuous on followup magnetic resonance imaging. In the remaining 77%, the posterior cruciate ligament was continuous from tibia to femur, although it appeared abnormally arcuate or hyperbuckled. Conventional interpretation of these magnetic resonance images would suggest that the posterior cruciate ligament had healed. Nevertheless, by clinical examination results, these same patients all were judged to have posterior cruciate ligament insufficiency. Thus, it was concluded that although magnetic resonance imaging may be reliable for evaluation of acute posterior cruciate ligament injury, magnetic resonance imaging findings should not be used to infer functional status in chronic cases.

Arthroscopic versus open reconstruction of the shoulder in patients with isolated Bankart lesions.

We compared open and arthroscopic stabilizations of true Bankart lesions in patients with traumatic, unidirectional anterior glenohumeral dislocations. The 27 patients were men (age range, 18 to 56 years) who were involved in recreational sports. One group (15 patients) had elected an arthroscopic Bankart repair; the other group (12 patients) had chosen open stabilization with a standard deltopectoral approach. Patients were followed up 17 to 42 months after surgery by examination, radiographs, and interviews. In the open repair group, 1 of the 12 patients experienced a subluxation in the follow-up period, but no patients had dislocations or reoperations. In the arthroscopic group, 5 of 15 patients had experienced subluxation or dislocation; of these 5 patients, 2 underwent reoperation. The arthroscopic group had significantly worse results in satisfaction, stability, apprehension, and loss of forward flexion in the operated limb. In summary, the arthroscopic procedure did not significantly improve function; instead, it produced an increased failure rate compared with the open procedure. Therefore, we believe that open stabilization remains the procedure of choice for patients with true Bankart lesions.

Lumbar transverse process fractures in professional football players.

In the general population, fractures of the transverse processes of lumbar vertebrae occur in cases of high-energy blunt trauma, often in motor vehicle accidents. Football players may incur the same fractures, but the circumstances and outcomes are different in this specific subgroup. A review of 29 cases among National Football League players reveals that associated visceral injuries are rare, and the time lost from sports is only an average of 3.5 weeks.

Occult osseous lesions associated with anterior cruciate ligament tears.

Occult osseous lesions occurring with anterior cruciate ligament tears have been described only recently. Twenty patients with complete anterior cruciate ligament disruptions and evidence of occult osseous lesions on their preoperative magnetic resonance (MR) images were evaluated retrospectively at 24- to 73-months' followup to document the natural history and long-term effects of the lesions. Thirty-seven initial osseous signal abnormalities were documented on the MR images of 20 patients. All 20 patients had lesions in the posterolateral tibial plateau, and 13 had additional lesions in the lateral femoral condyle. Twenty-four of the 37 osseous lesions appeared resolved on followup MR images, and 13 had become sclerotic. Lesions of the lateral tibial plateau were especially likely to be sclerotic at followup. This study reaffirms the specificity of bone signal abnormalities of the posterolateral tibial plateau and lateral femoral condyle in association with complete anterior cruciate ligament tears. The data indicate that a proportion of anterior cruciate ligament patients will incur progressive articular cartilage abnormalities, although case-by-case predictions based on initial MR images would be unreliable.

Arthroscopic posteromedial visualization of the knee.

Arthroscopic visualization of the posteromedial compartment of the knee via an anterolateral portal is not commonly practiced, yet it is relatively simple, has low morbidity, and is of diagnostic and therapeutic value. This prospective study evaluates posteromedial visualization of the knee joint in a series of 117 consecutive patients who underwent arthroscopy for diagnosis or treatment, or both, of 209 pathologic conditions. The technique was deemed simple to perform in 78% of patients. It was found to be more difficult in knees with degenerative joint disease. Posteromedial visualization was found to be essential for diagnosis or treatment in 4% of the diagnosed conditions, and helpful in an additional 13%. The technique was most useful for tears of the posterior horn of the medial meniscus, some of which were not detected by visualization from the anteromedial compartment alone. Visualization of the posteromedial compartment was deemed adequate in 89% of the patients, and there was no morbidity.

Lunate and perilunate dislocations in professional football players. A five-year retrospective analysis.

The purpose of this retrospective study was to review the treatment and prognosis of lunate and perilunate carpal dislocations in professional football players in the National Football League over a 5-year period. There were 7 lunate and 3 perilunate dislocations in 10 players. The mechanism of injury was hyperextension in 9 of 10 players. Five players were subsequently treated by closed reduction and percutaneous pinning; the others were treated by open reduction and K-wire fixation. No player was treated by cast immobilization alone. Intraoperative techniques, postoperative immobilization and protection, return to play, final follow-up physical examination, radiographic evaluation, and complications were reviewed. Results of this study clearly demonstrate that lunate and perilunate carpal dislocations do not mean the end of a career in professional football, although a minimum of 4 weeks of playing time is lost. Treatments varied with respect to open or closed reductions, placement of pins, casts, and time of immobilization. None of the variations was clearly superior or detrimental, although four of the five players who returned to play in the same season were treated by closed reduction with percutaneous pinning.

Experimental traumatic debonding of orthodontic brackets.

This study was designed to gather information on enamel damage concomitant with traumatic debonding of orthodontic brackets. Seventy-eight extracted premolars passed an inspection for defects and were bonded with metal or ceramic brackets. The samples were debonded by one of six methods: (1) conventional clinical debonding, (2) shear force applied slowly and directly onto the bracket, (3) slow shear force applied to an archwire between two brackets, (4 and 5) shear force rapidly applied to the bracket or archwire, or (6) rapid compression (impact) force applied to the face of the bracket. The teeth were microscopically inspected following debonding, and 28% were found to have enamel damage. Within the sample groups, the percentage of damaged samples ranged from 0 to 80%. While the sample sizes were insufficient to generate statistically significant results, there was evidence of the following: (1) Accidental debonding by rapidly applied forces presents a relatively high risk of enamel damage. (2) Ceramic brackets, because of their fragility, may offer some protection by shattering and thus dispersing a rapidly applied force. (3) Direct impact forces may be less dangerous than rapidly applied shearing forces.

Achilles tendon allograft reconstruction of the anterior cruciate ligament-deficient knee.

Thirty-five patients had reconstruction of the anterior cruciate ligament with intraarticular fresh-frozen Achilles tendon allograft and extraarticular tibial band tenodesis. Patients were followed 2 to 4 years (mean, 2.5). Evaluation included clinical and functional examinations, measurement of tibiofemoral displacement, and anteroposterior and lateral radiographs. Clinical results were considered satisfactory in 85% of the patients; 16 had arthroscopic examination after the allograft; allograft biopsies in 9 at this time showed cellular and vascular tissue without evidence of immune reaction. Clinical, arthroscopic, and biopsy results were favorable, but radiologic results were not. In most patients there was a significant size increase in femoral and tibial bone tunnels, as measured from radiographs. In the 6 most extreme cases, bone tunnels measured 20 mm or more in diameter, twice the initial size. Etiology and clinical significance of these bone tunnel changes remain unknown. Enlargement appears to occur early after operation; it stabilizes within 2 years. No statistical correlation was seen between tunnel enlargement and results of clinical and functional examinations; nevertheless, unexplained tunnel enlargement is cause for concern, and allograft replacement of the anterior cruciate ligament with fresh-frozen Achilles tendon allograft should be considered a salvage procedure.

Nickel-titanium spring properties in a simulated oral environment.

A study of nickel-titanium springs was undertaken to determine whether their mechanical properties are affected by prolonged exposure to a static, simulated oral environment. Stainless steel springs and polyurethane elastic chains were also studied for comparison. The springs were elongated to twice their rest length and held at that length while immersed in artificial saliva at body temperature for 0, 2, 4 or 6 weeks. Plots of force vs. deformation were made as the springs were stretched from rest length to three times that length and then relaxed back to rest. Nickel-titanium springs suffered no degradation of their spring properties in the simulated oral environment. In contrast, stainless steel springs became slightly more compliant to stretching, and polyurethane elastics lost a large portion of their force-generating capacity. These findings confirm and extend earlier reports which indicate that nickel-titanium is a preferred material for many orthodontic applications.

Use of a scanning laser three-dimensional digitizer to evaluate dimensional accuracy of dental impression materials.

A steel die was machined to represent a dental arch with teeth prepared for complete crowns. Impressions and casts were made from the die, and critical dimensions were measured by two methods--one using micrometers and the other a scanning laser three-dimensional (3-D) digitizer. The digitizer recorded measurements were more precise than the micrometer's and virtually eliminated operator error because the acquisition of data was automatic. The digitizer could also be useful for high-precision analyses of the dimensional accuracy of dental impression materials, but the cost and complexity of the instrument makes it less desirable for low-precision work.

Use of a scanning laser three-dimensional digitizer for analysis of dental materials.

A scanning laser 3-D digitizer was used to measure dimensions in dental impression materials, and its performance was compared with that of micrometer-based measuring instruments. It was found that the digitizer was precise enough to detect dimensional changes on the order of 40 microns, and it was automated enough to be convenient and almost eliminate operator errors. However, its operation required the services of an engineer for maintenance and a programmer for data analysis.

Immuno-labelling for freeze-fracture: application to a cell surface attachment antigen.

The cell-surface attachment (CSAT) antigen was investigated by using a technique that combines freeze-fracture with thin-sectioning. Chick heart cells were labelled using colloidal gold secondary antibodies, then fractured and shadowed with platinum vapor. The cells were dehydrated and embedded with their gold labels and replicated surfaces still intact. Sectioning revealed gold particles superimposed with external (E) fracture faces. The gold was definitely not coincident with E face particles and did not appear to be associated with pits. Therefore, it can be concluded that the CSAT glycoproteins is not represented by an E face particle. Whether it may be seen as an E face pit, or is not visible at all in freeze-fracture, is still an open question.

Acute lesion of the intrafusal muscle of muscle spindles: ultrastructural and electrophysiological consequences.

Experiments were performed to functionally separate the neural and muscular elements in muscle spindles. Cat muscle spindles were dissected free in vitro and were transected on both sides of the sensory nerve endings. This resulted in an acute lesion of the intrafusal muscle fibers but spared the sensory endings. Within 45 min, the intrafusal muscle fibers degenerated to the condition in which there were no myofilaments left in the sensory zone and the muscle fiber membrane had begun to disintegrate. During this degeneration period, and afterward, the sensory nerve fibers continued to fire action potentials. However, the postlesion discharge was usually more irregular than normal, and the mean rate of firing was often dramatically increased. In addition, multiplex frequencies of firing were often observed; that is, the interspike intervals were clustered around 2 or more modal values. Computer modeling of 2 action potential initiators competing for access to the same output line suggests that the multiplexing results from at least one of the competitors having a fraction of its spikes aborted. Overall, the results indicate that the nerve endings have an intrinsic capability to function as sensory receptors in the absence of a muscle substrate.

Effect of intrafusal muscle mechanics on mammalian muscle spindle sensitivity.

Sensitivity differences between primary and secondary endings of mammalian muscle spindles under various conditions of stretch and fusimotor activation may be due to differences in their respective mechanoelectric transducers or to mechanical properties of the intrafusal muscle supporting those endings. This study of isolated cat muscle spindles examines the strain in individual intrafusal muscle fibers resulting from stretch and fusimotor stimulation. The degree of local stretch occurring at the sensory endings under these conditions was measured. The results support the hypothesis that the sensitivities of primary and secondary endings are quite similar. They are directly related to the local stretch of the underlying muscle which may be altered by changes in muscle stress and stiffness.

Freeze-fracture of sensory nerve endings in cat muscle spindles.

Sensory nerve endings and intrafusal muscle fibres of cat muscle spindles were examined by freeze-fracture electron microscopy. The purpose of the study was to reveal intramembranous specializations that might be associated with the mechanosensory transducer system. Nerve ending membranes were found to contain high concentrations of intramembranous particles (greater than 7500 per micron2) in a range of sizes, but no localized aggregations or non-random arrangements were observed. Nerve ending membranes directly apposed to the surfaces of intrafusal muscle fibres did not appear to be strikingly different from non-interface membranes, although some differences in particle concentrations could be detected. The membranes of endings on nuclear bag and nuclear chain muscle fibres differed slightly in the numbers of particles and their distributions to protoplasmic or external fracture faces. It was concluded that intramembranous elements of the mechanoelectric transducer system may be dispersed over the whole surface of a sensory ending, rather than localized to smaller domains.