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Biomedical subjects

William P Cooney

Publications and source records attributed to William P Cooney.

At least 19 recordsLinked to original sources
PubMed2006

Revision of thumb trapeziometacarpal arthroplasty.

PURPOSE: To determine the incidence of revision surgery after thumb trapeziometacarpal joint arthroplasty and to present the expected results of future surgical treatment. METHODS: We reviewed the patient database at our medical center and found 654 procedures performed between 1988 and 2000 for the treatment of thumb basal joint arthritis. From the database we found that revision arthroplasties were performed on 15 patients with 17 arthroplasties in the treatment of mechanical pain related to instability or bone impingement. Referred patients with primary surgery performed elsewhere and patients with neurogenic pain were reviewed but not included as a primary focus of this study. The revision surgical procedures included soft-tissue interposition alone or soft-tissue interposition with ligament reconstruction for mechanical symptoms and neurolysis of peripheral nerves for associated neurogenic pain. The assessment included preoperative and postoperative patient chart review, measurement of pinch and grip strengths, radiographic assessment, and patient contact to provide complete medical information including any further medical or surgical treatment. RESULTS: Based on a grading system previously used to evaluate thumb revision surgery, objective good (or satisfactory) results were found in 13 of 17 revision procedures. The method of soft-tissue revision (resection with soft-tissue interposition or resection with ligament reconstruction) did not influence the outcome of good versus fair or poor results. Persistent failures (2 fair, 2 poor) resulted from both soft-tissue interposition alone and revision with ligament support arthroplasties. Revision arthroplasty with soft-tissue procedures for mechanical pain provided predictably good results unless a nerve injury occurred at the time of the revision surgery. CONCLUSIONS: Failure of primary thumb trapeziometacarpal arthroplasty can be salvaged by a second surgery with ligament reconstruction procedures combined with soft-tissue interposition and provides satisfactory patient outcomes in more than 75% of cases studied. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Aged↗
PubMed2006

Outcomes of dorsal capsulodesis and tenodesis for treatment of scapholunate instability.

PURPOSE: The ideal treatment for scapholunate (SL) instability has not yet been established. This study examined the results of 2 procedures for the primary treatment for chronic SL dissociation of dorsal capsulodesis and flexor carpi radialis tenodesis. METHODS: A retrospective analysis was conducted that examined dorsal capsulodesis and tenodesis procedures performed for chronic SL instability between January 1995 and February of 2003. Twenty-nine patients were identified with isolated chronic SL instability. Of the 29 patients, 14 had a dorsal capsulodesis procedure and 15 had a tenodesis procedure. The follow-up period averaged 38 months in the capsulodesis group and 36 months in the tenodesis group. Results were reviewed clinically and radiographically. Groups were compared with a Student t test. RESULTS: Postoperative wrist motion decreased in both groups after surgery. Final wrist range of motion was 64% of the unaffected side in the capsulodesis group and 63% of the unaffected side in the tenodesis group. Postoperative grip strength remained unchanged in both groups; grip strength measured 91% of the unaffected side in the capsulodesis group and 87% of the unaffected side in the tenodesis group. The average Mayo wrist scores were 77 in the capsulodesis group and 74 in the tenodesis group. One frank failure occurred in the tenodesis group resulting in a wrist fusion. There was no statistical difference in the overall wrist motion, grip strength, or wrist scores between the capsulodesis and tenodesis groups. CONCLUSIONS: Dorsal capsulodesis and tenodesis provided improvement in symptoms for patients with chronic SL instability. Both procedures appear to provide similar results in the treatment of this difficult problem.

Adult↗
PubMed2006

Biomechanical efficiency of wrist guards as a shock isolator.

Despite the use of wrist guards during skate- and snowboard activities, fractures still occur at the wrist or at further proximal locations of the forearm. The main objectives of this study were to conduct a human subject testing under simulated falling conditions for measurement of the impact force on the hand, to model wrist guards as a shock isolator, to construct a linear mass-spring-damper model for quantification of the impact force attenuation (Q-ratio) and energy absorption (S-ratio), and to determine whether wrist guards play a role of an efficient shock isolator. While the falling direction (forward and backward) significantly influenced the impact responses, use of wrist guards provided minimal improvements in the Q- and S-ratios. It was suggested based on the results under the submaximal loading conditions that protective functions of the common wrist guard design could be enhanced with substantial increase in the damping ratio so as to maximize the energy absorption. This would bring forth minor deterioration in the impact force attenuation but significant increase in the energy absorption by 19%, which would help better protection against fall-related injuries of the upper extremity.

Adult↗
PubMed2006

Internal fixation of dorsally displaced fractures of the distal part of the radius. A biomechanical analysis of volar plate fracture stability.

BACKGROUND: Volar plate fixation with use of either a locking plate or a neutralization plate has become increasingly popular among surgeons for the treatment of dorsally comminuted extra-articular distal radial fractures. The purpose of the present study was to compare the relative stability of five distal radial plates (four volar and one dorsal), all of which are commonly used for the treatment of dorsally comminuted extra-articular distal radial fractures, under loading conditions simulating the physiologic forces that are experienced during early active rehabilitation. METHODS: With use of a previously validated Sawbones fracture model, a dorsally comminuted extra-articular distal radial fracture was created. The fracture fixation stability of four volar plates (an AO T-plate, an AO 3.5-mm small-fragment plate, an AO 3.5-mm small-fragment locking plate, and the Hand Innovations DVR locking plate) were compared under axial compression loading and dorsal and volar bending simulating the in vivo stresses that are generated at the fracture site during early unopposed active motion of the wrist and digits. A single dorsal plate (an AO pi plate) was used for comparison, with and without simulated volar cortical comminution. The construct stiffness was measured to assess the resistance to fracture gap motion, and comparisons were made among the implants. RESULTS: The volar AO locking and DVR plates had greater resistance to fracture gap motion (greater stiffness) compared with the volar AO nonlocking and AO T-plates under axial and dorsal loading conditions (p < 0.01), with no significant difference between the AO volar locking and DVR plates. The volar AO locking plate had greater resistance to fracture gap motion than did the volar AO nonlocking plate under axial loading and dorsal bending forces (p < 0.01). The dorsal pi plate had the greatest resistance to fracture gap motion under axial loading and volar and dorsal bending forces (p < 0.01). However, the pi plate was significantly less stable to axial load and dorsal bending forces when the volar cortex was comminuted (p < 0.01). CONCLUSIONS: In this model of dorsally comminuted extra-articular distal radial fractures, dorsal pi-plate fixation demonstrated better resistance to fracture gap motion than did the four types of volar plate fixation. The AO volar locking and DVR plates conferred the greatest resistance to fracture gap motion among the four volar plates tested. Volar locking technology conferred a significant increase in resistance to fracture gap motion as compared with nonlocking plate technology.

Biomechanical Phenomena↗
PubMed2006

The hypoplastic thumb.

Thumb hypoplasia is part of a spectrum of radial longitudinal deficiencies involving the upper limb. Systemic involvement of other organ systems is not uncommon, thus requiring a team approach to management. Because of the variety of anatomic abnormalities associated with thumb hypoplasia, clinical and intraoperative evaluation of the thumb must be precise. Effective management of thumb hypoplasia requires an understanding of the embryology, epidemiology, classification, presentation, and management options. Management, which is primarily determined by the grade of thumb hypoplasia, may include nonsurgical techniques, reconstruction, pollicization, and, recently, microsurgical procedures.

Hand Deformities, Congenital↗
PubMed2005

Use of an ulnar head endoprosthesis for treatment of an unstable distal ulnar resection: review of mechanics, indications, and surgical technique.

Resection of the distal ulna for post-traumatic arthritis can lead to an unstable forearm joint through loss of the normal articular contact through the distal radioulnar joint and loss of soft tissue constraint. The resulting convergence instability can lead to residual pain, weakness, and loss of function. Restabilization of the forearm joint with implantation of an ulnar head endoprosthesis can re-establish the mechanical continuity of the forearm, reducing pain and improving strength and function. The anatomy, mechanics,rationale, and indications for surgical replacement of the distal ulna are presented. Important tenets of proper ulnar head implant insertion are given to provide a guide for use of the implant. Preliminary results after 2 years of clinical experience are encouraging.

Arthroplasty, Replacement↗
PubMed2005

Capsulodesis for the treatment of chronic scapholunate instability.

PURPOSE: Scapholunate (SL) instability is the most common form of carpal instability. The treatment of this disorder is challenging and varying treatment options have been described. The purpose of this study was to examine the intermediate-term results of dorsal capsulodesis for cases of chronic SL dissociation. METHODS: A retrospective analysis was conducted that examined all dorsal capsulodesis procedures performed for chronic SL dissociation between January of 1990 and February of 2000. Wrist pain had to be present for greater than 3 months. Patients had to have a minimum follow-up period of 2 years for inclusion in the study. Thirty-one patients were identified with isolated chronic SL dissociation. Of the 31 patients 18 had dynamic carpal instability and 13 had static carpal instability. The time from injury to surgery averaged 20 months. The follow-up period averaged 54 months (range, 24-96 mo). All patients had a dorsal capsulodesis procedure using either a Blatt or Mayo technique. Results were reviewed clinically and radiologically. Static and dynamic groups were compared with a Student t test. RESULTS: There was a 20% decrease in wrist motion after capsulodesis. There was no improvement in grip strength after surgery. Most patients had improvement in pain but only 2 patients were completely pain free. Radiographically the SL gap increased over time from 2.7 mm before surgery to 3.9 mm at the final follow-up evaluation. The SL angle also increased from 56 degrees before surgery to 62 degrees on final follow-up evaluation. There was no statistical difference in overall wrist motion, grip strength, or wrist score between the dynamic and static groups. The time to surgery and age had no significant effect on overall outcome. CONCLUSIONS: Dorsal capsulodesis provided pain relief for patients with both dynamic and static SL instability. Although pain was improved it was not completely resolved in the majority of cases. From a radiographic perspective dorsal capsulodesis did not provide maintenance of carpal alignment in cases of chronic SL dissociation.

Adolescent↗
PubMed2005

The use of the 4 + 5 extensor compartmental vascularized bone graft for the treatment of Kienböck's disease.

PURPOSE: The use of vascularized bone grafts for the treatment of Kienböck's disease may prevent ongoing lunate collapse and provide relief of wrist symptomatology. This study examines our experience with the use of the 4 + 5 extensor compartmental artery (ECA) bone graft for the treatment of Kienböck's disease. METHODS: A retrospective review was performed of all patients having pedicled vascularized bone grafts for Kienböck's disease between 1991 and 2002. Only those patients who had reconstruction with a 4 + 5 ECA graft were included in the study. Presurgical and postsurgical measurements included range of motion, grip strength, and pain evaluation. Measurements of the radiolunate angle, radioscaphoid angle, Stahl's index, and carpal height ratio were taken from presurgical and final follow-up radiographs. Postsurgical magnetic resonance imaging scans were also examined to verify revascularization of the lunate. Statistical analysis was performed using Student's t test. A chi-square test was used to evaluate the effects of lunate revascularization on radiographic progression of disease. Twenty-six 4 + 5 ECA vascularized bone grafts were performed as treatment for Kienböck's disease. The average patient age was 32 years. At the time of surgery 12 patients were graded as stage II, 10 as IIIA, and 4 as IIIB. Mean follow-up time was 31 months. RESULTS: At a mean follow-up of 3 months, motion improved from 68% to 71% of the unaffected side, grip strength improved from 50% to 89% of the unaffected side, and 92% of patients had significant improvement in their pain. Satisfactory results were seen in 85% of patients based on the Lichtman outcome score. Seventy-seven percent of patients showed no further collapse on postsurgical radiographs. Sixty-five percent of patients had follow-up magnetic resonance imaging scans at a mean of 20 months after surgery. Seventy-one percent of patients showed evidence of revascularization with improvement in the T2 and/or T1 signal. CONCLUSIONS: The 4 + 5 ECA bone graft provides a reliable alternative for the treatment of Kienböck's disease and may aid in lunate revascularization.

Adolescent↗
PubMed2005

Pediatric hand dressing: technical report.

A compressive or conforming dressing is an important aspect of hand surgery, particularly the role of uniform pressure to the entire hand. Pediatric hand patients require special considerations with respect to appropriate postoperative dressing to maintain equal limb compression and to maintain the dressing during the postoperative period. This article describes a specific upper-limb hand dressing that can be used in the infant and young child.

Bandages↗
PubMed2005

Revision total knees done for extensor problems frequently require reoperation.

UNLABELLED: We retrospectively reviewed 361 patients who had a revision total knee arthroplasty done for an extensor mechanism problem to assess the prevalence, etiology, and risk factors for subsequent reoperation. The prevalence of reoperation was 23% because 84 patients were reoperated on one or more times. The average time to the first reoperation was 2.4 years. The total number of reoperations was 127 with 58 patients reoperated on once, 15 reoperated on twice, and 11 reoperated on three or more times. The cumulative risk of a reoperation for any reason after index revision was 7% at 1 year, 19.6% at 5 years, and 35.9% at 10 years. The most common reason for reoperation was a new or recurrent patellofemoral problem, which accounted for 33% of the first reoperations. The risk of reoperation was substantially lower for patients that had femoral or tibial component malrotation corrected at the time of revision TKA. The risk of reoperation after revision TKA for an extensor mechanism complication increased in patients operated on in the 1990s compared with patients operated on in the 1970s and 1980s. LEVEL OF EVIDENCE: Therapeutic study, Level-IV-1 (case series). See the Guidelines for authors for a complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗
PubMed2004

Long-term assessment of Swanson implant arthroplasty in the proximal interphalangeal joint of the hand.

PURPOSE: The purpose of this study was to evaluate the clinical results of Swanson silicone implant arthroplasty of the proximal interphalangeal (PIP) joint, specifically evaluating clinical results with long-term assessment. METHODS: A retrospective review of 70 silicone implants of the PIP joint in 48 patients was performed with an average follow-up period of 6.5 years (range, 3-20 y). Clinical assessment included motion, stability, and alignment. Radiographic assessment included implant fracture, deformity, and cystic bone resorption. The pathology consisted of degenerative joint disease in 14, posttraumatic arthritis (TA) in 11, rheumatoid arthritis (RA) in 13, and idiopathic arthritis (IA) associated with collagen disease in 12 patients. Swan neck and boutonniere deformities were assessed separately. Statistical analysis of preoperative risk factors was compared with the postoperative assessment of pain, motion, and function (return to work). RESULTS: There was no significant change in the active range of motion (ROM) before and after PIP arthroplasty (26 degrees vs 30 degrees ). Correction of swan neck and boutonniere deformities was difficult, usually leading to poor results. There was improvement in maximum active extension before surgery lacking 32 degrees to after surgery lacking 18 degrees . From a statistical standpoint rheumatoid joint involvement with PIP arthroplasty had poorer results than degenerative or posttraumatic arthritis with respect to pain relief and ROM. Pain relief was present in 70% of replaced PIP joints with residual pain and loss of strength in 30%. Radiographic analysis showed abnormal bone formation (cystic changes) in 45%. There were 11 implant fractures and 9 joints that required revision surgery. CONCLUSIONS: Silicone replacement of the PIP joint is effective in providing relief of pain from arthritis but does not provide improvement in motion or correction of deformity. It provided a poorer outcome in rheumatoid disease in comparison with degenerative, posttraumatic, or idiopathic arthritis.

Arthritis↗
PubMed2004

Isolated scaphoid dislocation associated with axial carpal dissociation: an unusual injury report.

We present a report of a patient with an isolated scaphoid dislocation associated with a hyperextension and axial loading injury of the carpus required a careful and extensive clinical and radiographic evaluation leading to surgical intervention to reduce and stabilize the scaphoid and to reduce and hold internally the axial carpal injury. Knowledge of the anatomy and the potential injury patterns of the carpus will aid the hand surgeon with injury recognition and proper treatment.

Adult↗
PubMed2004

A quantitative method to measure maximal workspace of the trapeziometacarpal joint--normal model development.

INTRODUCTION: A reliable and quantitative method for measuring motion of the thumb is lacking. In particular, review of the previous methods of motion analysis of the thumb joints shows that there is no objective method for clinicians to assess the impairment of the thumb trapeziometacarpal (TMC) joint. Based on the concept of the three-dimensional (3-D) space within which the first metacarpal can move relative to the trapezium (a concept of defining and measuring the workspace of the TMC motion), we present a quantitative method for measuring motion and impairment (loss of function) of the TMC joint. METHODS: Twenty normal subjects were recruited in this study. An electromagnetic device was placed over the thumb metacarpal and long finger metacarpal, the 3-D relationship between them previously established. We measured the position and orientation of the TMC motion in space. Maximum movements of the thumb TMC joint in circumduction, flexion-extension and abduction-adduction were used to construct the 3-D maximal workspace of the TMC joint. Mathematical methods were used to verify the model and calculate the maximal workspace. RESULTS: The results of this study demonstrate accurate and repeatable measurement of 3-D TMC motion with high statistical reliability and low variability of the maximal TMC workspace. A statistically significant linear correlation between the maximal surface area and the square of the first metacarpal length was obtained. CONCLUSION: We conclude that a quantitatively comparative measurement of the range of motion of the TMC joint can be obtained with potential to measure motion in joints affected by arthritis or trauma and measured in both dynamic and static positions of the thumb.

Adult↗
PubMed2004

Reoperations after 3200 revision TKAs: rates, etiology, and lessons learned.

The purpose of this study was to evaluate the prevalence, etiology, and evolution with time of reoperations done after index revision total knee arthroplasties. After exclusion criteria were met, 1814 index knee revisions in 1627 patients were included in the final cohort with more than 50% of the revisions done for loosening and extensor mechanism problems and more than 80% of the revisions involving the femoral, tibial, or both components. Three hundred seventy-three knees subsequently have been reoperated on one or more times. The average time from index revision total knee arthroplasty to the first reoperation was 3.5 years (range, 1 day-19 years). Of the 1814 index revision total knee arthroplasties, 373 (20%) had 593 reoperations in 336 patients. The cumulative risks of first reoperation at 5, 10, and 15 years were 16.1% (95% CI, 14.2, 17.9), 26% (95% CI, 23.4, 28.6), and 31.4% (95% CI, 30.2, 39), respectively. There was no difference in risk to first reoperation when comparing the decades in which the index revisions were done (1970-1980, 1981-1990, and 1991-2000). There was a trend toward a higher cumulative risk of first time reoperations for deep infection, loosening, and instability in the last decade, but with the numbers available this was not statistically significant. The prevalence of reoperations in this large series of index revision total knee arthroplasties done for aseptic reasons was surprisingly high. Despite substantial improvements during the past 3 decades in component design, surgical technique, and prevention of infection, patients who have a revision total knee arthroplasty are at substantial risk of having one or more subsequent problems that result in a reoperation.

Arthroplasty, Replacement, Knee↗
PubMed2003

Feasibility of using surface markers for assessing motion of the thumb trapeziometacarpal joint.

OBJECTIVE: The purposes of the present study were to investigate the feasibility of using a skin sensor to represent the first and third metacarpal bone, to verify that there was no significant relative motion between the skin of the third metacarpal bone and trapezium bony segment and to measure thumb metacarpal motion with respect to the hand (third metacarpal). DESIGN: Eight hands from fresh-frozen human cadavers were disarticulated 4 cm proximal to the wrist joint and used in this experiment. BACKGROUND: Recently, magnetic-tracking systems have been developed for the measurement of joint kinematics. Based on the concept of the three-dimensional space within which the thumb metacarpal bone can move, the current study proposes a 3D method for evaluating the relationship between the skin and bony segment. METHODS: An electromagnetic tracking system was used to provide quantitative measurement and evaluation of the relationship between the skin and bony segment while moving the trapeziometacarpal joint. RESULTS: The adjusted coefficient of multiple determination, R(a)(2), values of the kinematic waveforms between the sensors were larger than 0.84. The angular differences and displacements of the center of sensors between the skin and bony sensors were less than 4.9 degrees and 2.8 mm. CONCLUSION: These data revealed that the similarities of the two sensors throughout the motion cycle were high. The differences between the two sensors were also within the clinically allowable range of +/-5 degrees. Therefore, it is feasible to collect motions of the first metacarpal by attaching the skin sensors at the metacarpal head to measure the bony segment.

Aged↗
PubMed2003

Kinematic and torque-related effects of dorsally angulated distal radius fractures and the distal radial ulnar joint.

PURPOSE: The purpose of this study was to examine the torque required to achieve a full range of motion of the distal radioulnar joint (DRUJ) as a result of increasing dorsal angulation from simulated fractures of the distal radius. Based on this study the accepted amount of dorsal angulation of the distal radius can be determined. METHODS: In 9 fresh cadaver limbs motion of the DRUJ was simulated by a custom motion and loading forearm device. The malunion model of the distal radius was controlled by a specially designed external fixation frame that provided control in 6 degrees of dorsal angulations (N, 0 degrees, 10 degrees, 20 degrees, 30 degrees, and 40 degrees ). The study included an intact and nonintact triangular fibrocartilage complex. RESULTS: This study showed that torque across the DRUJ was affected by the degree of simulated malunion of the distal radius. With more than 30 degrees dorsal angulation the torque across the DRUJ was increased in both muscle loading and unloading conditions. Although significance was not noted, with resistive loading this study showed torque changes with as little as 10 degrees malunion of the distal radius. CONCLUSIONS: We conclude that reduction of distal radius fractures to within 10 degrees of dorsal angulation is needed to allow patients to maintain full forearm and wrist rotation.

Aged↗