Patients With Intact Shoulder Superior Capsular Reconstruction Grafts on Ultrasound Show Significant Improvement in Functional Outcomes at Minimum 2-Year Follow-up

Purpose

To assess the utility of using dynamic ultrasound for postoperative evaluation after superior capsular reconstruction (SCR) by evaluating graft integrity and its correlation with clinical outcomes at a minimum 2-year follow-up.

Methods

A retrospective chart review was conducted to identify patients who underwent SCR between July 2015 and July 2020 with a minimum 2-year clinical and ultrasound follow-up. Clinical outcome measures included Simple Shoulder (SS) and American Shoulder and Elbow Surgeon (ASES) scores. Integrity of the SCR graft was evaluated by dynamic ultrasound.

Results

We evaluated 22 shoulders in 21 patients with a mean follow-up of 44.8 months (range, 24-71 months). The graft was found to be intact by ultrasound evaluation in 82% (18/22). Patients with intact grafts had higher mean SS (11.6 vs 7.8, P = .00079) and ASES (91.2 vs 64.1, P = .0296) scores at latest follow-up compared to those with failed grafts. Those with intact grafts also had significant improvement in SS (3.7 vs 11.6, P < .00001) and ASES (23.2 vs 91.2, P < .00001) scores at latest follow-up compared to their preoperative scores. In contrast, patients with graft failure had no significant improvement in SS (6.3 vs 9.0, P = .123) and ASES (40.4 vs 58.3, P = .05469) scores at latest follow-up compared to their preoperative scores. There was no difference between clinical outcomes at 6 to 12 months vs latest follow-up for both SS (P = .11, P = .5) and ASES (P = .27, P = .21) scores.

Conclusions

SCR grafts were found by ultrasound to be intact in 82% of cases. Patients with intact grafts on ultrasound had significant improvement in functional outcome scores while those with graft failure did not. Functional outcome scores suggest that maximal recovery from this procedure occurs by 6 to 12 months.

Level of Evidence

Level IV, therapeutic case series.

Ultrasound-Assisted Posterior Knee Arthroscopy: A Description of the Technique

Entering the posterior knee with arthroscopy can be difficult. Scar tissue, a tumor, and the obese patient can make instrument placement difficult and risk iatrogenic injury. Ultrasound can be used to visualize the posterior knee and provide direct guidance of instrumentation. We describe the technique and indications for using ultrasound during arthroscopy. Accurate and atraumatic insertion of instruments can be performed with no damage to total knee components or the knee joint. Ultrasound guidance should be considered during difficult posterior knee arthroscopy.

Adoption of Intramedullary Nail Fixation for Proximal Humerus Fractures: Assessment of Surgical Efficiency and Complications

Fixation of proximal humerus fractures (PHFs) with intramedullary (IM) nails potentially is a newer, less invasive technique. The purpose of this study was to report on the early adoption results of IM nail use for PHF. Retrospective chart reviews were performed on the first 60 patients treated with IM nails for acute PHFs by two shoulder surgeons. The first 15 patients treated by each surgeon were compared with the subsequent 15 patients. Surgical and fluoroscopic times, fracture type, union, and varus collapse were compared. The average operating time decreased (p = .002). Fluoroscopy time, radiographic alignment, union rate, complications, and reoperations were not influenced. Three- and four-part fractures had a higher complication rate than two-part fractures (53% vs. 20%). When considering implementing use of IM nails for treatment of PHFs, initial cases can have outcomes and complications similar to those performed with greater experience. IM nailing appears a good treatment option for two-part PHFs. (Journal of Surgical Orthopaedic Advances 28(2):121-126, 2019).

Pigmented villonodular synovitis: extrasynovial recurrence

A 32-year-old female athlete underwent arthroscopy for a second recurrence of pigmented villonodular synovitis (PVNS), which was extrasynovial, seen on magnetic resonance imaging. It was noted on arthroscopy that (1) the nodules moved medially with joint insufflation, (2) the nodules were less prominent than on magnetic resonance imaging, and (3) more than 95% of the recurrent tumor was hidden by neosynovium. We believe that the extrasynovial location is because of the more rapid proliferation of the neosynovium relative to the growth of the remaining tumor cells after the previous resection. In resecting pigmented villonodular synovitis with a high risk of recurrence, a layer of periarticular fat should be removed and the surgeon should be wary of change in position with insufflation.

Evaluation of the learning curve for reverse shoulder arthroplasty

This purpose of this study was to quantify the surgical learning curve and provide guidelines to surgeons interested in teaching and performing reverse shoulder replacement. Sixty-two consecutive primary reverse shoulder replacements performed by a single surgeon were retrospectively reviewed. Using data from consecutive cases, surgical time was plotted against patient case order, and the linear regression slope was calculated. Case length slope analysis demonstrated a significantly negative slope with the first 18 cases, which subsequently leveled thereafter. The number of cases needed to arrive at this flat slope was defined as the proficiency point.The proficiency point was then verified using the measurable variables of baseplate screw number and glenosphere overhang by dividing the series into 2 groups: Group A included patients who had surgery prior to the proficiency point, and group B included patients who had surgery after the proficiency point. In group A, only 33% (6/18) had all 4 glenoid baseplate screws placed as compared to 66% (29/44) in group B (P=.02). Glenosphere overhang increased from a mean of 1.02 mm (+/-1.29 mm) in group A to 2.58 mm (+/-1.89 mm) in group B (P=.003).A learning curve of approximately 18 cases was found in this series based on the technical aspects of performing reverse shoulder replacement. This curve is likely even longer for lower volume shoulder surgeons. We recommend specialized training prior to performing this procedure.

Fenestrated cannulae with outflow reduces fluid gain in shoulder arthroscopy

Soft tissue fluid retention is a common problem after arthroscopy, with as much as 2% of patients having complications develop. A fenestrated outflow cannula has been introduced to reduce interstitial swelling. We tested the ability of this outflow cannula design to reduce fluid weight gain. We enrolled 28 patients undergoing shoulder arthroscopy and randomized them into two groups using fenestrated outflow versus conventional cannulae. The conventional group had greater weight gain as a function of the procedure duration than the fenestrated outflow group (slope = 0.542 +/- 1.160 kg/hour versus 0.0144 +/- 0.932 kg/hour). The conventional group also had greater weight gain as a function of fluid volume than the fenestrated outflow group (slope = 0.022 +/- 0.038 kg/L versus 0.002 +/- 0.341 kg/L). Compared with conventional nonoutflow cannulae, fenestrated outflow cannulae with negative pressure reduced weight gain associated with longer arthroscopic surgeries and increased arthroscopic fluid volume.

LEVEL OF EVIDENCE

Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Removal of well-fixed flanged humeral prostheses may require humeral expansion

BACKGROUND

A flanged humeral stem design can be advantageous in achieving an interlock between the prosthetic and bone interface leading to a long-term stable loading pattern. The purpose of this study is to report a short case series involving revision of a flanged humeral prosthesis. Our hypothesis was that a greater percentage of the flanged prostheses undergoing revision would require some form of bone expansion to achieve stem removal compared to the nonflanged.

METHODS AND RESULTS

In the period from October 2004 to July 2008, 43 patients underwent revision of a humeral prosthetic stem by a single surgeon. Of these, 6 prostheses were of a triflanged design. Of these six, five (83%) could not be removed with longitudinal force and required some expansion of the bone in order to achieve stem extraction. Of the nonflanged humeral stems, 3/37 (8%) required bone expansion to achieve extraction. Analysis of the 2 groups showed a statistical difference in the need for humeral expansion (P < .000001).

CONCLUSIONS

Surgeons preparing to revise a flanged humeral stem should include expansion of the humeral shaft, by episiotomy or windowing, as part of their preoperative planning and informed consent of the patient.

The accuracy of the saline load test in the diagnosis of traumatic knee arthrotomies

OBJECTIVES

When open joint injury is suspected in a knee laceration, the saline load test has been recommended as a diagnostic modality, especially in small wounds, where inspection and palpation cannot confirm joint violation. The goals of this study are: 1) to correlate fluid volume needed for positive diagnosis with demographic factors, 2) to assess the sensitivity of using the commonly recommended volume of 50 mL, and 3) to identify the minimum fluid volume necessary to obtain 95% sensitivity.

DESIGN

Prospective cohort.

SETTING

University medical center.

PATIENTS/PARTICIPANTS

Thirty consecutive patients scheduled for elective outpatient knee arthroscopy were prospectively enrolled. Exclusion criteria include history of open traumatic injury, presence of active infection, or limited range of motion as evidence of arthrofibrosis.

INTERVENTION

A standard lateral parapatellar portal was made with a no. 11 blade scalpel, and a 5.8 mm diameter cannula-trochar was inserted and withdrawn to create a standard arthrotomy size of 26.4 mm. Using an 18-gauge needle, saline was injected through a separate lateral suprapatellar site until outflow was noted.

MAIN OUTCOME MEASUREMENTS

Upon fluid outflow, the volume of injected saline was recorded.

RESULTS

The volume injected until outflow was similar between men and women (P = 0.87). No correlation was observed between the volume injected and age (P = 0.85), height (P = 0.18), weight (P = 0.46), and body mass index (P = 0.91). Injection of 50 mL successfully identified only 46% of known arthrotomies. A saline load of 194 mL was required to achieve 95% sensitivity.

CONCLUSIONS

For small lacerations around the knee, saline loads of less than 194 mL are of questionable sensitivity, and surgeons should not use the saline load test to rule out open knee injuries.

Assessment of reprocessed arthroscopic shaver blades

PURPOSE

The purpose of this study was to evaluate the level of contaminants on, as well as the quality of, reprocessed shaver blades.

METHODS

We assessed 7 new shaver blades and 27 shaver blades that had been reprocessed with mechanical cleaning, functional testing, and sterilization with ethylene oxide. A spectrophotometer measured the amount of nucleic acid and protein. The blade quality was assessed by photographing the blades with magnification and determining the percentage of damage present on each blade. A subset of shaver blades were then used to cut meniscal tissue, and the cut surface was measured for smoothness by image processing and automated laser scanning cytometry. In evaluation of the meniscus, for the subset of shavers, an image processing value of 1 indicates a smooth, straight line, and values lower than 1 reflect deviations in the cut surface (the closer the value is to 1, the smoother the surface). Laser scanning cytometry values indicate the percentage of irregularities in the cut surface (the lower the value is, the smoother the surface).

RESULTS

Of the 27 reprocessed shaver blades, 13 (48%) had detectable levels of protein and 17 (63%) had detectable levels of nucleic acid. On the reprocessed shaver blades, protein levels ranged from 2.43 microg to 60 microg and nucleic acid levels ranged from 0.40 microg to 3.5 microg. No new shaver blade had contaminants. Twenty reprocessed shaver blades had been manufactured with teeth and could be evaluated for visible damage. Of these, 10 had 1% to 25% damage, 5 had 26% to 50% damage, 3 had 51% to 75% damage, and 2 had 76% to 100% damage. The new blades had no visible damage. Image processing revealed smoothness of the surface cut with new shaver blades, yielding values of 1 +/- 0.12, whereas the values for reprocessed shaver blades ranged from 0.62 +/- 0.02 to 1 +/- 0.07. Laser scanning cytometry values ranged from 3.3% to 7.1% for the new blades as compared with 5.8% to 20.0% for the reprocessed blades.

CONCLUSIONS

Of the reprocessed shaver blades, 48% had detectable levels of protein and 63% had detectable levels of nucleic acid. All of the reprocessed blades visually evaluated showed some level of damage or wear, whereas no new blade had such damage. In addition, menisci cut with reprocessed shavers showed rougher edges than did menisci cut with new shavers.

CLINICAL RELEVANCE

To make an informed decision regarding the use of reprocessed shaver blades, surgeons will want to know the level of contamination on, and the quality of, reprocessed shaver blades.

In vitro effects of 3 common arthroscopic instruments on articular cartilage

PURPOSE

The purpose of this study was to compare chondroplasty performed with an ExoJet high-pressure fluid-driven burr (Mitek, Norwood, MA), a mechanical shaver, and a bipolar radiofrequency (RF) wand on articular cartilage-covered condyles taken from sheep cadavers that were induced to have an osteoarthritic-like condition, and corresponding healthy control tissue.

TYPE OF STUDY

Experimental designed animal cadaveric, biochemical, and histologic study.

METHODS

Sheep condyles were used as a source of articular cartilage. Femurs were extracted approximately 1 hour postmortem and a transverse section of the condyles was made. Half of the samples were treated to induce an osteoarthritic-like condition. The condyles were then subjected to chondroplasty performed with the ExoJet high-pressure fluid-driven burr, a mechanical shaver, and a bipolar RF wand under sterile saline solution by an experienced orthopaedic surgeon. Twenty cross-sections from each condyle were examined by confocal microscopy to measure smoothness and depth of tissue damage to the articular cartilage caused by each of the 3 instruments.

RESULTS

The ExoJet high-pressure fluid-driven burr and the bipolar RF wand left a smoother surface on the articular cartilage compared with the mechanical shaver. Additionally, the ExoJet fluid-burr caused slightly less tissue damage to the cartilage than the bipolar RF wand, both of which were less damaging than the shaver.

CONCLUSIONS

Orthopaedists have multiple choices for surgical instruments used on cartilage. However, the effect on the integrity of the cartilage left remaining at the knee was previously unknown. Based on this study, a fluid-burr appears to leave the cartilage with a smaller zone of injury than does the RF wand or shaver. It also leaves the cartilage surface smoother than the shaver. During surgical procedures, minimizing cartilage breakdown and smooth remaining surfaces are desired because they minimize the vulnerable tissue to further destruction. A fluid burr leaves cartilage with less injury and with a smoother surface than do more traditional surgical instruments.

CLINICAL RELEVANCE

This information should help surgeons in their selection of currently available surgical instruments and should aid engineers in the design of future instruments that function to modify articular cartilage.

Shaver, bipolar radiofrequency, and saline jet instruments for cutting meniscal tissue: a comparative experimental study on sheep menisci

PURPOSE

The purpose of this study was to compare the quality of meniscal tissue cut with 3 different surgical instruments (traditional shavers, bipolar radiofrequency (RF) wands, and a high-pressure saline jet) and that of control menisci.

TYPE OF STUDY

Experimental design, biochemical and histologic study.

METHODS

Sixty samples of sheep menisci were separated into 4 groups. Three groups were shaved on the apical surface with the different instruments. The smoothness of the cut surfaces was evaluated visually by an orthopaedic surgeon and then scored by laser scanning cytometry and by line measurement analysis. The depth of tissue damage was measured by fluorescent cytochemistry. Means and standard deviations were calculated and comparative statistics used (P < .05).

RESULTS

The edges cut by the saline jet and bipolar RF were significantly smoother when judged by the surgeon than those cut by traditional shaver. There was no significant difference between the saline jet and bipolar RF. There were no significant differences in smoothness when measured by laser scanning cytometry or by line measurement techniques. The control menisci had less depth of damage along the edge as measured by fluorescent cytochemistry than did any of the menisci cut with the instrument. The saline jet had significantly less depth of damage than did the shaver. No other significant differences existed between the instruments for depth of damage.

CONCLUSIONS

The results of our investigation conclude that high-pressure saline instruments may cause less damage to residual meniscal tissue when compared with bipolar RF and shavers. Saline jets and bipolar RF also produce a smoother cut than shavers.

CLINICAL RELEVANCE

Surgeons may want to consider the degree of residual damage to meniscal tissue from the application of various surgical instruments. Saline jets may be a superior cutting instrument than RF or shavers when considering depth of residual damage and smoothness of residual meniscal edges.

An anatomic evaluation of the active compression test

The goal of this study was to describe the anatomic relationships present during the active compression test. Four pairs of cadaveric shoulders were positioned to simulate the active compression test. The shoulders were embedded in polyurethane and evaluated in the axial and coronal planes with a planer. In the axial plane, all internally rotated shoulders demonstrated contact between the lesser tuberosity and subscapularis tendon and the superior aspect of the glenoid and labrum. In the externally rotated position, there was no contact between the superior structures of the shoulder. In the coronal plane, the internally rotated specimens revealed contact between the supraspinatus tendon and the lateral aspect of the acromion. There was no contact between the supraspinatus tendon and the acromion when the shoulders were externally rotated in the coronal plane. The results demonstrate that the active compression test can be used to assist in the diagnosis of superior labrum anterior-posterior lesions as well as other shoulder pathology.

Damage to cobalt-chromium surfaces during arthroscopy of total knee replacements

BACKGROUND

It has been stated that care must be taken not to scratch the metal components during total knee arthroscopy; however, this concern has not been studied. Clinical observation during arthroscopy of total knee replacements suggested the possibility of damage to the femoral component by the arthroscopic cannula; therefore, a bench test was performed to study this potential risk.

METHODS

Cobalt-chromium femoral components were tested to determine the surface damage that resulted from moving a stainless-steel arthroscopic cannula and a plastic arthroscopic cannula across the components under a variety of applied loads. Scanning electron microscopy and surface-roughness measurements of the prosthetic surface were used to evaluate the damage.

RESULTS

The stainless-steel cannula produced observable alterations to the surface of the femoral component at loads as small as 8 N. The majority of these alterations were deposits of stainless steel from the cannula onto the component. The plastic cannula did not appear to produce alterations on the component surface. Surface roughness increased with increasing loading of the stainless-steel cannula, but there was no noticeable change with increasing loading of the plastic cannula. These forces did, however, severely damage some parts of the plastic cannula.

CONCLUSIONS

Alterations to the surface of cobalt-chromium femoral components can occur during arthroscopy with stainless-steel cannulae but not with plastic cannulae. The results of this study support a recommendation to use plastic cannulae during arthroscopy of total knee replacements.

CLINICAL RELEVANCE

Arthroscopy of total knee replacements is increasing in the clinical setting, and damage to the prosthesis should be avoided whenever possible. This study provides evidence that damage to the femoral component is possible with a stainless-steel cannula and that use of a plastic cannula may reduce this risk.

Evaluation of impingement syndromes in the overhead-throwing athlete

OBJECTIVE

We outline impingement entities, describe the history and physical examination, and provide an overview of treatment beyond that routinely used in glenohumeral and scapulothoracic dysfunction.

BACKGROUND

In the athlete, pain and dysfunction due to excessive overhead use or abnormal positioning of the shoulder is common and can result from multiple etiologies, including impingement syndromes. Primary, secondary, internal, and coracoid impingement have all been described.

DESCRIPTION

These entities will be discussed, including pathology, evaluation, and treatment.

CLINICAL ADVANTAGES

Incorporating a systematic evaluation and treatment of impingement syndromes optimizes care for the patient with shoulder pain.

Fixation of proximal humeral prostheses and rotational micromotion

Twenty pairs of cadaveric humeri were used to compare the rotational stability of proximal humeral prostheses fixed by proximal cementation with the stability offered by press fit or full cementation. For each proximally cemented specimen, only the upper portion of the prosthesis was coated with cement. For the fully cemented specimens, a cement restrictor was used just distal to the prosthesis, and a finger-packing technique was used to fill the proximal humeral medullary canal. Torque was applied to the Morse taper of the prostheses, and rotational micromotion was measured at the level of the osteotomy. In each of 11 pairs of cadaveric humeri, one side was press fit and the contralateral side was proximally cemented; in each of 9 pairs, proximal cementation was compared with full cementation. Proximally cemented prostheses' micromotion was significantly less than that of press-fit prostheses (P = .0016). There was no difference in micromotion between proximal cementation and full cementation (P = .82). Proximal cementation increased initial fixation over press fit. Full cementation did not increase rotational stability.

Shoulder dislocations in patients older than 40 years of age

Shoulder dislocations in patients over 40 years of age are common and are frequently associated with serious injuries to adjacent structures. Associated injuries such as brachial plexus injury, rotator cuff tear, axillary artery injury, fractures about the shoulder, and recurrent dislocation can make shoulder dislocations challenging problems for the clinician. Early diagnosis and treatment of associated injuries and treatment complications are the mainstays in prevention of morbidity and, even, mortality.

Anatomy of provocative tests for impingement syndrome of the shoulder

The purpose of this study was to describe the extra- and intra-articular anatomic relationships present during the Neer and Hawkins tests. Nine fresh-frozen cadaveric shoulders were positioned in the impingement position described by Neer (n = 5) or that described by Hawkins (n = 4), embedded in polyurethane, and studied with the use of a cross-sectional technique. All shoulders placed in the Neer position demonstrated soft tissue contact with the medial acromion and contact between the articular surface of the rotator cuff tendons and the anterosuperior glenoid rim. Shoulders placed in the Hawkins position demonstrated consistent contact between soft tissues and the coracoacromial ligament. In all Hawkins positioned shoulders, contact between the articular surface of the rotator cuff tendons and the anterosuperior glenoid was observed. The subscapularis tendon was deformed by the coracoid in 1 of the Hawkins positioned specimens. Although factors inherent to human subjects such as edema and muscle tone may influence the anatomy, these provocative tests for subacromial impingement appear to elicit contact consistent with impingement.

Fixation of humeral prostheses and axial micromotion

Surgeons often avoid cementing a proximal humeral prosthesis. Occasionally bony augmentation is needed. This study was undertaken to compare proximal cementation in combination with distal press with total cementation or press fit alone. In phase 1 axial micromotion with axial loading was measured in 15 pairs of humeri: 5 fully cemented versus proximally cemented, 5 fully cemented versus press fit, and 5 proximally cemented versus press fit. X-ray films of the specimens were obtained to assess canal fill. In phase 2 axial micromotion was measured in 5 pairs of high mineral density and 5 pairs of low mineral density to compare proximal cementation with press fit. The 3 M modular prosthesis was used in both phases. No difference was found in phase 1 among the 3 fixation techniques. A strong reverse statistical correlation (P = .007) (r = .55) was seen between axial micromotion and fill of the canal with the prosthesis. In the second phase no statistically significant difference was found between the techniques of fixation or between the 2 bone densities. Fill of the canal at the distal end of the prosthesis was the only variable found that affected axial micromotion, but it accounted for only approximately 30% of the variance. Bone quality and augmentation of the proximal bone with cement did not affect axial micromotion in this experiment but warrant further study.

Posterior to anterior transglenoid pins: anatomy at risk

Pneumothorax was noted after an arthroscopic procedure during which a small guidewire overpenetrated the glenoid from a posterior-superior direction. This anatomic study was undertaken to determine the structures at risk from pins overpenetrating from the posterior-superior aspect and to determine whether scapulothoracic position altered the risk. The glenoid was intentionally overpenetrated with wooden dowels from the posterior-superior aspect of the glenoid in seven fresh cadaveric shoulders. The dowels were placed arthroscopically using the Suretac instrumentation (Acufex Microsurgical, Mansfield, MA). The specimens were planed, and the relationship of these wooden pins to vital structures was evaluated. In all specimens, the dowels entered the thoracic cavity between the first and second ribs, regardless of scapular position. The pins consistently passed posterior to the neurovascular bundle but were precariously close, with an average distance to the closest neurovascular structure of 7.4 mm (range, 1 to 19 mm). Scapular position did not seem to affect this relationship.

Superior glenoid impingement

Superior glenoid impingement, a recently recognized mechanism of injury, puts five structures at risk: (1) the rotator cuff, (2) the superior labrum, (3) the greater tuberosity, (4) the superior glenoid, and (5) the inferior glenohumeral ligament. The clinical picture depends on which structures are injured and is still poorly described; however, the natural history is comprehensive for overhead athletes.

Superior glenoid impingement. Current concepts

In the current decade impingement syndrome is becoming a less precise diagnostic entity. It is splitting into several categories of more exact diagnoses. The concept development, clinical picture, and currently recommended treatment of 1 of these entities, the superior glenoid impingement is reviewed. The complaint may be acute or chronic and may involve 1 or more of 5 structures: (1) superior labrum, (2) rotator cuff tendon, (3) inferior glenohumeral ligament, (4) greater tuberosity, and (5) the bony glenoid. The most commonly seen clinical entity is chronic dorsal shoulder pain in an athlete who throws with a positive relocation test. Treatment consists of strengthening of the cuff and scapular rotators. When there has been excessive inferior ligament stretch this must be augmented by anterior reconstruction.

Spinal accessory nerve in a trapezius-splitting surgical approach

To elucidate the safe limits for muscle-splitting incisions of the trapezius muscle, 25 cadaver shoulders were studied. To describe the position of the nerve distances were expressed as a percentage of the distance from the tips of the vertebral spinous processes to the lateral tip of the acromion. The spinal accessory nerve was found to run a vertical course medial and parallel to the vertebral border of the scapula. Three to six nerve branches (average 3.8) also ran a vertical course lying between 33% to 50% of the distance from the tips of the vertebral spinous processes to the lateral tip of the acromion. The most lateral branch lay an average at 44% distance and never beyond 50%. Muscle-splitting incisions are relatively safe in the lateral 50% of the muscle. In the medial half they are to be avoided or pursued with great caution.

Shoulder instability in the overhand or throwing athlete

In the young throwing athlete with shoulder pain, it is essential to recognize that glenohumeral joint instability (occult subluxation, rather than impingement) is the primary underlying pathology. Fortunately, conservative management is effective in most chronic overuse injuries. For those athletes with continued symptoms, surgical intervention may become necessary. The anterior capsulolabral reconstruction addresses the problem of glenohumeral joint instability by correcting the capsular redundancy, labrum damage, or both. The authors believe this most recent surgical technique and postoperative rehabilitation program has resulted in a significant improvement in our ability to more predictably and successfully return these athletes to prior competitive levels.

Posterior superior glenoid impingement: expanded spectrum

Posterior superior glenoid impingement is a recently recognized mechanism of injury producing rotator cuff injury in athletes. Usually the mechanism is repetitive overhand activity such as throwing. A survey of the author's practice was undertaken to show a wider spectrum of this mechanism both in the activity that caused it and the number of structures at risk of injury from this mechanism. The survey revealed 11 patients who had a clear recollection of their mechanism of injury and an objective documentation of the injury by arthroscopy or imaging studies. The majority of shoulders had damage to more than one of the five structures at risk from this mechanism of injury. Six cases were not sports related. Glenoid impingement may injure one or more of the following: (1) superior labrum, (2) rotator cuff tendon, (3) greater tuberosity, (4) inferior glenohumeral ligament or labrum, and (5) superior glenoid bone. Injury to more than one structure may be the rule and injury to one structure may indicate investigation of the other four.

Acromial compromise with use of a transacromial portal: a biomechanical study

In an experimental evaluation with 14 paired cadaveric scapulae we found that the transacromial arthroscopy portal, used occasionally in the repair of superior labral lesions, will reduce the structural integrity of the acromion to approximately 60% (range 25% to 85%) of its original strength, thereby placing it at increased risk of fracture. These studies provide baseline biomechanical information and suggest that limited shoulder activity is indicated after use of this portal.

Limits imposed on glenohumeral motion by joint geometry

Contact of the greater tuberosity against the glenoid raises the question of the limits imposed on motion by glenohumeral joint geometry. In 50 cadaveric shoulders the arcs of articular cartilage on the humeral head and glenoid in the frontal and axial planes were measured or calculated. In the coronal plane the humeral heads had an arc of 159 degrees (+/- 8.5 degrees) covered by 96 degrees (+/- 8 degrees) of glenoid, leaving 63 degrees (+/- 10 degrees) of cartilage uncovered. In the transverse plane the humeral arc of 160 degrees (+/- 11 degrees) is opposed by 74 degrees (+/- 6 degrees) of glenoid, leaving 86 degrees uncovered. The 159 degrees of coronal humeral arc articulating with the transverse glenoid has 88 degrees (+/- 9 degrees) of cartilage uncovered. The geometry of the glenohumeral joint limits motions that occur in simple arcs. The obligate external rotation that occurs in elevation is necessary to make more humeral cartilage available for articulation with the glenoid.

Neuroanatomy in elbow arthroscopy

An injury to the median nerve from within the joint during an arthroscopic synovectomy prompted a study of the relationship of the nerves to the capsule and bones of the elbow. Six pairs of cadaveric elbows frozen in 90 degrees of flexion and one pair frozen in extension were sectioned at 5-mm intervals, and the distances from the major nerves to the bones and capsule were recorded. One elbow joint in each pair was filled with saline solution. Saline solution insufflation increased the nerve-to-bone distance with the elbow in flexion. The results were 12 mm for the median nerve and 6 mm for the radial nerve. The capsule-to-nerve distance was affected little by insufflation and was as narrow as 6 mm in three specimens. Extension eliminated the protective effects of insufflation and brought the nerves closer to the bone. These findings confirm (1) the importance of flexion and insufflation in portal placement, (2) that insufflation does not improve the capsule-to-nerve distance, and (3) the potential for "from within-out" injury in synovial procedures.

Subdeltoid lipoma presenting as subluxation of the glenohumeral joint

This case illustrates that space-occupying lesions beneath the heavily collagenated portion of the deltoid can produce a confusing clinical picture mimicking subluxation. This patient's clinical presentation was quite extraordinary in its resemblance to glenohumeral instability. The case also illustrates the importance of imaging studies in confirming questionable diagnoses. Such studies should be read by the surgeon, and any discrepancies from the radiologist's reading should be addressed.

Amputation salvage with microvascular free flap from the amputated extremity

Microvascular surgery has allowed creative primary reconstruction using undamaged parts of amputated limbs as donor sites. We present a case of lower extremity below-knee amputation salvage with a free flap of heel, calcaneus, and soft tissues from the amputated lower leg, ankle, and foot supplied by the posterior tibial neurovascular bundle.

Special properties of living tissue that affect the shoulder in athletes

The physiologic function of the structures of the shoulder is to withstand the forces that arise from activity without sustaining injury. From our understanding of the biology of these tissues, we can see how they modify themselves to prevent injury and react, appropriately or inappropriately, to injury. This information, and knowledge yet to be discovered in the laboratory, should lead to more effective surgery, physical therapy, and use of medication.

Painful athletic injuries of the shoulder

Pain in the athlete's shoulder is likely to have a mechanical origin, because the athlete performs repetitive high-stress activity. Proper treatment is based on understanding the biomechanics and physiology of the tissues, as well as the demands of the patient's specific athletic activity. Correct rehabilitation is the key to successful conservative and surgical management. A return to previous activity depends on restoring the normal biomechanics, either through conservative management or surgery. Some of these problems are unsolved and remain fruitful areas for future research.