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Biomedical subjects

Jon J P Warner

Publications and source records attributed to Jon J P Warner.

At least 19 recordsLinked to original sources
PubMed2006

Pectoralis major tendon reference (PMT): a new method for accurate restoration of humeral length with hemiarthroplasty for fracture.

For hemiarthroplasty reconstruction of a proximal humeral fracture, accurate restoration of humeral head position is challenging, and incorrect prosthetic placement is associated with a poor outcome of surgical treatment. The purpose of this study was to validate the pectoralis major tendon as a reproducible landmark for accurate restoration of humeral length with hemiarthroplasty reconstruction. We dissected 20 cadavers (40 shoulders), and the distance between the upper border of the pectoralis major tendon insertion on the humerus and the top of the humeral head was measured (PMT). The PMT averaged 5.6 +/- 0.5 cm (with a confidence level of 95%). In only 4 of 40 shoulders did this distance exceed 6.0 cm, and there was no correlation between the size of the patient and this measurement. The PMT is a useful landmark that will aid in accurate restoration of humeral length when reconstructing complex proximal humeral fractures where landmarks are otherwise lost because of fracture comminution.

Adult↗
PubMed2006

Proximal humeral fractures: regional differences in bone mineral density of the humeral head affect the fixation strength of cancellous screws.

The purpose of this study was to investigate the 3-dimensional trabecular bone mineral density (BMD) in the humeral head and determine the effects of trabecular BMD on the pullout strength of cancellous screws. Five regions of interest (ROIs) were defined in the humeral head (superior- anterior, superior-posterior, central, inferior-anterior, and inferior-posterior). The trabecular BMD of each ROI was determined by use of peripheral quantitative computed tomography. Cancellous screws were inserted in each ROI and cyclically loaded. The superior-anterior ROI had a lower trabecular BMD than all other ROIs (P < .001). The central ROI had a higher trabecular BMD than the inferior-anterior ROI (P < .01), whereas no differences were found between the inferior-posterior, superior-posterior, and central ROIs. Pullout strength was lower in the superior-anterior ROI compared with all other ROIs (P < .01). The trabecular BMD and pullout strength were significantly correlated (P < .01). Placement of screws in regions with a higher trabecular BMD may help to prevent implant loosening and may improve patient outcome.

Aged↗
PubMed2006

Trans-cuff portal for arthroscopic posterior capsulorrhaphy.

Arthroscopic repair of posterior shoulder instability is becoming an accepted method of treatment. Most surgeons perform this procedure with the patient in a lateral decubitus position to facilitate access to the posterior glenoid. We have developed an accessory portal placed through the midportion of the rotator cuff that allows easy and complete viewing of the posterior glenohumeral joint when the patient is in a beach chair position and does not require the use of traction. This portal provides a superior-to-inferior view of the posterior glenoid rim and capsule and allows use of anterior and posterior routine portals for posterior Bankart repair. In this study, the technique of posterior labral repair in the beach chair position with use of the trans-cuff portal is described, and preliminary results in 5 patients at an average follow-up of 24 months are presented. Through this approach, we were able to place 3 anchors, with the lowest at the 7 o'clock position (for a right shoulder), in all patients. Mean American Shoulder Elbow Surgeons (ASES) score improved from 53 +/- 15 preoperatively to 87 +/- 8 postoperatively (P < .01). All patients had an excellent result with complete resolution of pain and instability.

Adolescent↗
PubMed2006

Analysis of transfusion predictors in shoulder arthroplasty.

BACKGROUND: We are not aware of any previous study that has examined predictive factors for blood transfusion after shoulder arthroplasty. We analyzed the association between clinical factors and the need for postoperative blood transfusion and documented the use and waste of predonated blood in a group of patients managed with shoulder arthroplasty. METHODS: A retrospective study of 119 patients who underwent 124 shoulder arthroplasties (including eighty-seven primary uncomplicated total shoulder arthroplasties, twenty-seven revision or complicated primary total shoulder arthroplasties, and ten hemiarthroplasties) from 2001 to 2004 was performed. Logistic regression analysis was conducted to determine which clinical variables were predictive of transfusion. RESULTS: A postoperative transfusion was received after thirty-one arthroplasties (25%). The strongest predictor of blood transfusion after shoulder arthroplasty was the preoperative hemoglobin level (likelihood ratio test = 37.8, p < 0.0001). Patients with a preoperative hemoglobin level of between 110 and 130 g/L had a five times greater estimated risk of transfusion than those with a level of >130 g/L (p < 0.001). Gender, body mass index, preoperative diagnosis, comorbid conditions, use of anticoagulants or aspirin, autologous predonation status, type of anesthesia, operative time, and decrease in hemoglobin or hematocrit were not predictors of blood transfusion. One hundred and two (78%) of the 131 predonated autologous units were discarded. Patients with a preoperative hemoglobin level of >130 g/L had the highest percentage of wasted units (90%; fifty-five of sixty-one). Preoperative autologous blood donation did not eliminate the risk of allogeneic blood transfusion in autologous donors. CONCLUSIONS: The preoperative hemoglobin level is the strongest predictor of blood transfusion after shoulder surgery, and individuals with a preoperative hemoglobin level of <110 g/L have the highest risk of transfusion. On the basis of these findings, we do not recommend autologous predonation for individuals with a preoperative hemoglobin level of >130 g/L, to avoid unnecessary expense and waste.

Adult↗
PubMed2006

Recurrent posterior shoulder instability.

Recurrent posterior shoulder instability is an uncommon condition. It is often unrecognized, leading to incorrect diagnoses, delays in diagnosis, and even missed diagnoses. Posterior instability encompasses a wide spectrum of pathology, ranging from unidirectional posterior subluxation to multidirectional instability to locked posterior dislocations. Nonsurgical treatment of posterior shoulder instability is successful in most cases; however, surgical intervention is indicated when conservative treatment fails. For optimal results, the surgeon must accurately define the pattern of instability and address all soft-tissue and bony injuries present at the time of surgery. Arthroscopic treatment of posterior shoulder instability has increased application, and a variety of techniques has been described to manage posterior glenohumeral instability related to posterior capsulolabral injury.

Biomechanical Phenomena↗
PubMed2006

Rehabilitation of the rotator cuff: an evaluation-based approach.

Rotator cuff disease of the shoulder, a common condition, is often incapacitating. Whether nonsurgical or surgical, successful management of rotator cuff disease is dependent on appropriate rehabilitation. Numerous rehabilitation protocols for the management of rotator cuff disease are based primarily on anecdotal clinical observation. The available literature on shoulder rehabilitation, in conjunction with clinical observation that takes into consideration the underlying tissue quality and structural integrity of the rotator cuff, can be compiled into a set of rehabilitation guidelines. The four phases of rehabilitation begin with maintaining and protecting the repair in the immediate postoperative period, followed by progression from early passive range of motion through return to preoperative levels of function.

Biomechanical Phenomena↗
PubMed2005

Anatomical glenoid reconstruction for recurrent anterior glenohumeral instability with glenoid deficiency using an autogenous tricortical iliac crest bone graft.

BACKGROUND: Anterior shoulder instability associated with severe glenoid bone loss is rare, and little has been reported on this problem. Recent biomechanical and anatomical studies have suggested guidelines for bony reconstruction of the glenoid. HYPOTHESIS: Anatomical glenoid reconstruction will restore stability in shoulders with recurrent anterior instability owing to glenoid bone loss. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Eleven cases of traumatic recurrent anterior instability that required bony reconstruction for severe anterior glenoid bone loss were reviewed. In all cases, the length of the anterior glenoid defect exceeded the maximum anteroposterior radius of the glenoid based on preoperative assessment by 3-dimensional CT scan. Surgical reconstruction was performed using an intra-articular tricortical iliac crest bone graft contoured to reestablish the concavity and width of the glenoid. The graft was fixed with cannulated screws in combination with an anterior-inferior capsular repair. RESULTS: At mean follow-up of 33 months, the mean American Shoulder and Elbow Surgeons score was 94, compared with a preoperative score of 65. The University of California, Los Angeles score improved to 33 from 18. The Rowe score improved to 94 from a preoperative score of 28. The mean motion loss compared with the contralateral, normal shoulder was 7 degrees of flexion, 14 degrees of external rotation in abduction, and one spinous process level for internal rotation. All patients returned to preinjury levels of sport, and only 2 complained of mild pain with overhead sports activities. No patients reported any recurrent instability (dislocation or subluxation). The CT scans with 3-dimensional reconstructions obtained 4 to 6 months postoperatively demonstrated union of the bone graft with incorporation along the anterior glenoid rim and preservation of joint space. CONCLUSION: Anatomical reconstruction of the glenoid with autogenous iliac crest bone graft for recurrent glenohumeral instability in the setting of bone deficiency is an effective form of treatment for this problem.

Adult↗
PubMed2005

Panacryl synovitis: fact or fiction?

PURPOSE: It has been suggested from anecdotal experience that Panacryl suture (Ethicon, Johnson & Johnson, Westwood, MA) may be responsible for an exaggerated inflammatory response. Our goal was to test the null hypothesis that Panacryl causes aseptic synovitis when used on anchors in the case of arthroscopic Bankart and rotator cuff repair. TYPE OF STUDY: Retrospective review of the postoperative outcome, specifically looking for clinical criteria that are associated with aseptic synovitis. METHODS: Eighty-three arthroscopic Bankart and 33 arthroscopic rotator cuff repairs were performed using anchors loaded with Panacryl. The clinical factors associated with synovitis that we assessed were motion, pain, hyperthermia, and swelling. RESULTS: There was no hyperthermia. Two patients had transient swelling and 10 patients had initial transient postoperative pain. One patient had chronic pain and a second arthroscopy was performed 5 months after the initial procedure, which revealed obvious synovitis. Biopsy examinations were performed and these showed typical foreign-body reaction. Two anterior redislocations occurred after new traumas, 2 failed rotator cuff repairs were observed, due to early active motion, and 2 underwent an open revision repair; synovitis was not observed in any of these cases. After 6 months, the loss of external rotation was a mean of 6.7 degrees (Bankart) and 3.3 degrees (rotator cuff repair). The loss of forward elevation was a mean of 5.8 degrees (Bankart) and of 3.3 degrees (rotator cuff repair). CONCLUSIONS: In only 1 of 116 cases of arthroscopic repair was there direct evidence of synovitis. Even in the cases undergoing revision surgery, there was no indication that Panacryl caused aseptic synovitis. Clinical course after these repairs appeared to be similar to historical experience using nonabsorbable braided suture material. Failure rates in each series appeared to be more related to new trauma and use of other implants than to Panacryl suture. LEVEL OF EVIDENCE: Level IV.

Arthroscopy↗
PubMed2005

Arthroscopic versus mini-open rotator cuff repair: a cohort comparison study.

PURPOSE: To critically compare arthroscopic and mini-open rotator cuff repair. TYPE OF STUDY: Retrospective case control study. METHODS: Nine patients who had an arthroscopic rotator cuff repair (ARCR) were matched for age, gender, dominance, side of injury, history of trauma, duration of symptoms, and type of rotator cuff injury, with 12 patients who had a mini-open rotator cuff repair (MOR). Comparison included a preoperative and postoperative physical examination as well as a completed Simple Shoulder Test (SST) questionnaire at the latest follow-up at a minimum of 27 months. RESULTS: Both groups had significant reductions in pain scores (P < .01) and there was no significant difference in preoperative or postoperative active flexion or external rotation between both groups (P > .20). Although the ARCR group showed a significant improvement in strength (P < .01) and the MOR group did not, no patient had less than 4/5 strength. The impingement sign remained positive in 1 MOR patient, but all patients had a negative Jobe's test result. Pain and Tasks assessment by SST questionnaire showed that neither group had night pain or discomfort when using their arms overhead. There were no significant differences in the overall SST scores between groups. CONCLUSIONS: Because all patients in each group were satisfied with the procedure and there were no objective differences in outcome, we conclude that there is no difference in outcome between ARCR and MOR. Thus, the choice of one approach over the other is best based on surgeon or patient preference. LEVEL OF EVIDENCE: Level III, Retrospective Case Control Study.

Activities of Daily Living↗
PubMed2005

Arthroscopic versus open Bankart repair: analysis of patient subjective outcome and cost.

PURPOSE: Although the comparative efficacy of open and arthroscopic Bankart repair remains a matter of debate, little data exist on relative costs. We analyzed the patient outcomes, cost, and resource utilization of both procedures to determine if differences exist between open versus arthroscopic Bankart repair. TYPE OF STUDY: Retrospective case-control study. METHODS: We compared 22 patients who had open Bankart repair with 20 patients who had arthroscopic Bankart repair. Total operating times and all charges were obtained from records. Patients were evaluated using the American Shoulder and Elbow Surgeons (ASES) shoulder score, and any recurrence of dislocation was noted at minimum 24-month follow-up. RESULTS: For arthroscopic Bankart repairs, operating times were shorter, but operating room equipment charges were greater. Overall charges were greater for open repairs as all open repair patients were admitted postoperatively. ASES shoulder scores were not significantly different between treatment groups. Four of 17 evaluable patients with open Bankart repair (including 1 shoulder in a patient who underwent bilateral repairs) had recurrent dislocation. One of the 18 evaluable patients with arthroscopic Bankart repair had recurrent dislocation. CONCLUSIONS: Arthroscopic Bankart repair as same-day surgery has lower overall charges than open repair, although this difference would be negligible if all patients went home immediately after surgery. LEVEL OF EVIDENCE: Level III, therapeutic, retrospective cohort study.

Adolescent↗
PubMed2005

Open operative treatment for anterior shoulder instability: when and why?

The treatment of anterior glenohumeral instability continues to evolve. Open capsulolabral repairs are time-tested and reliable. In an era in which arthroscopic techniques continue to improve, open surgery remains an acceptable option, and there are still certain injury patterns that cannot be adequately addressed arthroscopically. Decision-making regarding surgery for instability is influenced by the surgeon's experience and the relevant pathological findings. Open operative treatment is the preferred approach in many instances of recurrent anterior instability, particularly when there is bone and soft-tissue loss and in revision settings.

Humans↗
PubMed2005

Quantitative morphology of the scapula: normal variation of the superomedial scapular angle, and superior and inferior pole thickness.

This study examined the normal variation of the superomedial scapular angle and the thickness of the superior and inferior scapular borders. Scapulae of 53 cadaver shoulders were dissected free from all soft tissue. A line was drawn from the most superior to the most inferior point on each scapula, and the scapulae were cut along this line to obtain cross sections. The supero-medial scapular angle (alpha) was measured with a goniometer from the cross section as a ABC: through the inferior tip (A), base of the spine (B), and superior tip (C). Superior and inferior pole thickness was measured with a digital caliper from the thickest portions on the cross section of the poles. Average superomedial angle was 139 degrees +/- 6 degrees (range: 125 degrees - 156 degrees). Average thickness for the superior and inferior poles was 3.9 +/- 0.9 mm (range: 2.1 - 8.3 mm) and 7.5 +/- 1.5 mm (range: 4 - 11 mm), respectively. The thickness of both superior and inferior poles was significantly different between male and female specimens (P < .05), with male scapulae having the higher values.

Aged↗
PubMed2004

Anchor design and bone mineral density affect the pull-out strength of suture anchors in rotator cuff repair: which anchors are best to use in patients with low bone quality?

BACKGROUND: Different metal and biodegradable suture anchors are available for rotator cuff repair. Poor bone quality may result in anchor loosening and tendon rerupture. HYPOTHESES: Higher bone mineral density is associated with higher pull-out strength of suture anchors. Depending on anchor placement, pull-out strengths of anchors are different within the greater tuberosity. STUDY DESIGN: Cadaveric biomechanical study. METHODS: Trabecular and cortical bone mineral densities were determined for different regions within the greater tuberosity. Metal screw-type and biodegradable hook-type anchors were cyclically loaded. RESULTS: Mean failure load of metal and biodegradable anchors was 273 N and 162 N, respectively, for the proximal part (P < .01) and 184 N and 112 N, respectively, for the distal part (P < .01). Both types of anchors showed higher failure loads in the proximal-anterior and -middle parts of the greater tuberosity than in the distal part (P < .01). A significant positive correlation was found between cortical bone mineral density and failure load of metal anchors (P < .01). CONCLUSION: Bone quality, anchor type, and anchor placement have a significant impact on anchor failure loads. CLINICAL RELEVANCE: Suture anchors should be placed in the proximal-anterior and -middle parts of the greater tuberosity. In the distal parts, biodegradable hook-like anchors should be used with caution.

Aged↗
PubMed2004

Variations in glenoid rim anatomy: implications regarding anchor insertion.

PURPOSE: The purpose of this study was to investigate normal bony anatomy of the glenoid rim and to define the angles for successful anchor placement for anterior and posterior labral repairs. TYPE OF STUDY: An anatomic study using cadaveric shoulder specimens. METHODS: Soft tissue was dissected from 20 cadaveric shoulders, and the glenoids were isolated. The glenoid specimens were scanned to obtain cross-sectional images using peripheral quantitative computed tomography (pQCT) in 4 different planes. Glenoid rim angles were measured from the cross-sectional pQCT images of the glenoids at 5 positions: the 3-o'clock, 4:30-, 6-, 7:30-, and 9-o'clock positions. Glenoid morphology was noted for each position. RESULTS: The glenoid rim angles from the 3-o'clock to the 9-o'clock positions were 53 degrees +/- 5 degrees, 45 degrees +/- 7 degrees, 80 degrees +/- 10 degrees, 61 degrees +/- 10 degrees, 49 degrees +/- 4 degrees, respectively. Asymmetric morphology of the glenoid was noted with an almost straight line extending medially from the rim at the 3-o'clock position, whereas a concave morphology was noted at the 9-o'clock position. Similarly at the 4:30-o'clock position, the scapular bony surface did not curve toward the base as markedly as it did at the corresponding posterior 7:30-o'clock position. CONCLUSIONS: The available bone mass for the anchor insertion was found to vary depending on the position of the glenoid rim. Both rim angle and glenoid morphology for each position must be considered when selecting the ideal anchor insertion angle for labral repair.

Aged↗
PubMed2004

Arthroscopic repair of SLAP lesions with a bioknotless suture anchor.

The diagnosis and treatment of SLAP tears have improved with the development of arthroscopic shoulder surgery techniques. With types 2 and 4 tears, the goal is to restore stability to the labrum and biceps anchor and achieve healing to the glenoid. Suture repair with anchors is currently the repair technique of choice. The purpose of this article is to report a fast and simple method for arthroscopic SLAP repair that uses knotless suture anchors and obviates complex suture management and arthroscopic knot tying.

Absorbable Implants↗
PubMed2004

Glenoid wear after shoulder hemiarthroplasty: quantitative radiographic analysis.

Symptomatic glenoid arthrosis may limit the long-term success of shoulder hemiarthroplasty in patients who are young and functionally demanding. The principal objective of the current study was to quantify glenoid wear after proximal humeral replacement in young, active subjects. Eight patients, ages 21 to 60 years (mean, 45 years), met inclusion criteria. The mean followup was 43 months. Functional scores for the cohort averaged 60% of age and gender-adjusted healthy subjects (range, 28%-84%). Glenohumeral joint space was measured on serial axillary radiographs using a Microscribe 3-DX digitizing device (measurement accuracy, 0.23 mm). Progressive glenoid wear was found in all eight patients. The mean decrease was 2 mm (range, 1.3-2.8 mm), a 68% decrease in glenohumeral joint space. Glenoid cartilage wear also was correlated with Constant and Murley scores. Patients with residual joint spaces less than 1 mm had a mean score of 50%, compared with a score of 71% for patients with joint spaces greater than 1 mm. There were no correlations between wear and mechanism of injury, duration of symptoms, and prior surgery. This study suggests that glenoid cartilage erosion can be expected routinely after humeral head replacement in young, active individuals, and that such wear may adversely affect function or necessitate conversion to total shoulder arthroplasty.

Adult↗