Christopher O. Bayne

Evaluation of the Accuracy and Use of X-Ray Markers in Digital Templating for Total Hip Arthroplasty

Despite benefits of digital templating, digital image acquisition techniques often make image magnification unknown and variable. We assessed the accuracy of digital x-ray scaling devices based on position. Radiographs of 106 total hip arthroplasty (THA) patients were studied to determine the accuracy of 2 digital x-ray markers at 1 of 4 positions by comparing true to expected x-ray magnification. The Pearson r coefficient was calculated as an indicator of measurement correlation between investigators. Greater accuracy was obtained for markers placed at the greater trochanter without skin overlap than for markers placed with soft tissue or bone overlap on x-ray. Flexible positioning markers provided greater accuracy than adhesive markers. Based on our data, we suggest positioning at the greater trochanter without skin overlap on x-ray and suggest flexible positioning over adhesive marker use.

Acute Arterial Thrombosis After Bilateral Total Knee Arthroplasty

Arterial thrombosis is a rare complication of total knee arthroplasty (TKA). The overall incidence of arterial complications after TKA, including arterial occlusion, arteriovenous fistula, arterial aneurysm, and arterial severance, varies between 0.03% and 0.17% in reports published in the orthopedic literature (J Vasc Surg 1994;20:927-932). We report a case of acute popliteal artery thrombosis and its sequelae immediately following bilateral TKA performed sequentially under the same anesthesia. This is the first reported case of a post-TKA popliteal artery thrombosis in a patient younger than 60 years without the commonly accepted risk factors.

A New Technique for Volar Capsulodesis for Isolated Palmar Scapholunate Interosseous Ligament Injuries: A Cadaveric Study and Case Report

Introduction Most surgical techniques for scapholunate interosseous ligament (SLIL) repair address only the dorsal component of the ligament, potentially leading to high surgical failure rates. We introduce a new technique to reconstruct the volar SLIL using a portion of the long radiolunate ligament (LRL). A biomechanical evaluation was performed to evaluate the rupture strength of this repair, and a subsequent anatomic study was performed to verify that this repair would not compromise the blood supply to either the scaphoid or the lunate. Methods A reconstruction of the volar SLIL was developed utilizing a lunate-based strip of the LRL. Fourteen cadaver arms were injected with red-colored epoxide and latex. The blood supply of the volar wrist capsule was dissected. The vascular supply to the ligaments, scaphoid, and lunate were investigated. The biomechanical strength of this reconstruction was tested on five cadaver arms by potting the scaphoid, lunate, and radius and subjecting the repair to a tensile load using a servohydraulic vertical displacement testing machine. Results In all arms, a branch of the radial artery or radiocarpal arch supplied the radioscapholunate ligament at the medial border of the LRL. The proximal half of the scaphoid was supplied by dorsal branches of the radial artery. In all cases, a vessel entered the lunate on its ulnar volar side, away from the repair. The average strength of the intact LRL strip was 97.4 N, and the average strength of the ligament-suture interface used for the capsulodesis was 43.5 N. Conclusion This volar approach to the SLIL does not compromise the vascularity of the scaphoid or the lunate. This approach allows the possibility of repairing or augmenting the volar SLIL. The strength of this repair appears to be less than the strength of the native SLIL. Further clinical studies are warranted.

Technique of harvest of the free vascularized fibula.

Vascularized free fibula transfer is an attractive option for the treatment of segmental bone defects because of faster union rates, fewer fatigue fractures, rapid hypertrophy, and less resorption compared with nonvascularized bone transfer. It is classically indicated for those patients with segmental bone defects >6 to 8 cm. The presence of several peroneal artery fasciocutaneous perforators also makes the inclusion of a skin paddle possible. Although rare, the surgeon must be aware of possible complications associated with this procedure. A careful operative technique is necessary for obtaining excellent surgical outcomes.

Outcomes of Capitohamate Bone-Ligament-Bone Grafts for Scapholunate Injury

Purpose In an attempt to restore natural carpal kinematics more closely, bone-ligament-bone (BLB) grafts have been described for treating scapholunate (SL) injury. In this article we report the long-term results of capitohamate BLB autograft for the treatment of SL dissociation. Methods The medical records of patients treated with capitohamate BLB grafts for SL dissociation were retrospectively reviewed. Twenty-three patients were available for evaluation. Patients were sent a Disabilities of the Arm, Shoulder, and Hand (DASH) and a Patient-Rated Wrist Evaluation (PRWE) questionnaire and returned for exam. Thirteen patients returned the questionnaire, and 12 wrists were examined. Range of motion, grip strength, pain, complications, return to work, and radiographic parameters were documented. Results The average length of follow-up evaluation was 9.2 years. The average SL gap was 4.5 mm preoperatively and 3.6 mm at final follow-up. The average SL angle was 70 degrees preoperatively and 73 degrees at final follow-up. There was no statistically significant difference in preoperative versus postoperative flexion, extension, radial deviation, ulnar deviation, or grip strength. The average postoperative visual analog scale (VAS) score was 1.25 at rest and 3.58 with activity. The average Mayo Wrist Score was 66.8 preoperatively and 70.9 postoperatively (p = 0.158). The average postoperative PRWE was 20.5, and average postoperative DASH was 15.1. At final follow-up, four patients had no radiographic evidence of arthritis. Two patients had evidence of early-stage radiocarpal arthritis, four had evidence of midcarpal arthritis, and two had radiographic evidence of mild scaphotrapeziotrapezoid arthritis. One patient required a salvage procedure with four-corner fusion. Discussion BLB reconstruction can be used to treat SL instability. At final follow-up, the majority of patients did not worsen clinically or functionally or require secondary salvage procedures; however, radiologic progression of arthritis was not prevented. These outcomes are comparable to midterm results of other SL reconstructive options; thus, we have abandoned this technique for other less technically demanding procedures. Level of Evidence IV.

Clinical Outcomes of the Flexor Carpi Ulnaris Turnover Flap for Posterior Elbow Soft Tissue Defects

PURPOSE To report the clinical outcomes from 2 academic centers of the flexor carpi ulnaris (FCU) flap for coverage of posterior elbow soft tissue defects. METHODS We retrospectively reviewed 17 patients who underwent an FCU flap for posterior elbow wound reconstruction over an 8-year period at 2 academic centers. Outcome measures included visual analog score for pain; Disabilities of the Arm, Shoulder, and Hand score; Mayo Elbow Performance score; range of motion; wound healing; grip strength; and isokinetic dynamometry for wrist flexion. Wilcoxon signed-rank test was used to make side-to-side comparisons between the operative and nonsurgical extremities, and nonparametric statistical methods were used to analyze results. RESULTS All wounds healed successfully without need for revision surgery. Average visual analog, Disabilities of the Arm, Shoulder, and Hand, and Mayo Elbow Performance scores in the operative elbow were 1.8, 34, and 86, respectively. Average elbow arc of motion was 11° to 140° with 70° forearm pronation and 73° forearm supination. Compared with the nonsurgical side, grip strength on the operated side was 97% and wrist flexion peak torque was 89%. The operative limb had an average wrist flexion fatigue of 7%, compared with 22% for the nonsurgical arm. CONCLUSIONS Patients receiving an FCU flap had reliable healing, minimal pain, good functional outcomes, and no meaningful deficits in grip strength or wrist flexion strength. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic IV.

The outcome and complications of vascularised fibular grafts

Aims Free vascularised fibular grafting has been used for the treatment of large bony defects for more than 40 years. However, there is little information about the risk factors for failure and whether newer locking techniques of fixation improve the rates of union. The purpose of this study was to compare the rates of union of free fibular grafts fixed with locking and traditional techniques, and to quantify the risk factors for nonunion and failure. Patients and Methods A retrospective review involved 134 consecutive procedures over a period of 20 years. Of these, 25 were excluded leaving 109 patients in the study. There were 66 men and 43 women, with a mean age of 33 years (5 to 78). Most (62) were performed for oncological indications, and the most common site (52) was the lower limb. Rate of union was estimated using the Kaplan‐Meier method and risk factors for nonunion were assessed using Cox regression. All patients were followed up for at least one year. Results The rate of union was 82% at two years and 97% at five years. Union was achieved after the initial procedure in 76 patients (70%) at a mean of ten months (3 to 19), and overall union was achieved in 99 patients (91%). No surgical factor, including the use of locked fixation or supplementary corticocancellous bone grafts increased the rate of union. A history of smoking was significantly associated with a risk of nonunion. Discussion Free vascularised fibular grafting is a successful form of treatment for large bony defects. These results suggest that the use of modern techniques of fixation does not affect the risk of nonunion when compared with traditional forms of fixation, and smoking increases the risk of nonunion following this procedure.

Sex-dependent Relationship Between Wrist Deviation and Scaphoid Kinematics

Several methods of describing patterns of carpal kinematics from radiographs have emerged due to their potential use in developing personalized treatments for wrist pathologies. Such radiography-derived metrics have been used to infer associations between patterns of scaphoid kinematics and other clinically relevant factors such as sex, but the simultaneous effects of sex and wrist position on scaphoid kinematic metrics has yet to be considered. We sought to investigate the relationship between wrist position in the coronal plane and radiographic measurements of the scaphoid for each sex independently, then identify sex-specific differences in scaphoid measurements and calculated metrics. We retrospectively identified 38 subjects with posteroanterior radial and ulnar deviation radiographs. Radiographic scaphoid measurements were collected and used to calculate five scaphoid kinematic metrics per participant. We used Pearson correlation coefficients to explore the relationships between the degrees of wrist deviation in the coronal plane and radiographic scaphoid measurements for men and women independently. We used the non-parametric Wilcoxon signed-rank test to compare values between sexes. The correlations between degrees of coronal wrist deviation and radiographic measurements of scaphoid inclination were significant only for men. Men also had significantly greater values for all radiographic scaphoid measurements. Our study demonstrated sex-specific differences in the relationship between the degrees of radial and ulnar wrist deviation and scaphoid positioning. Clinical Relevance Our findings show the importance of stratifying by sex in studies of carpal kinematics, such as scaphoid kinematics, and that investigation of strategies to restore normal carpal function should incorporate sex as a biological variable.

Real-time three-dimensional MRI for the assessment of dynamic carpal instability

Carpal instability is defined as a condition where wrist motion or loading creates mechanical dysfunction, resulting in weakness, pain and decreased function. Often the diagnosis is made late when malalignment is visualized on static radiography, CT, or MRI. When conventional imaging methods do not identify the instability patterns, yet clinical signs associated with instability exist, the diagnosis of dynamic instability is often suggested to describe carpal derangement manifested only during the wrist’s active motion or stress. We addressed the question: can advanced MRI techniques provide quantitative measures for evaluating dynamic carpal instability and supplement standard static MRI acquisition? Our objectives were to [1] develop a real-time, three-dimensional MRI method to image the carpal joints during their active, uninterrupted motion; and [2] demonstrate feasibility of the method for assessing metrics relevant to dynamic carpal instability, thus overcoming limitations of conventional MRI. Twenty wrists (bilateral wrists of ten healthy participants) were scanned during radial-ulnar deviation and clenched-fist maneuvers. Images resulting from two real-time MRI pulse sequences, four sparse data acquisition schemes, and three constrained image reconstruction priors were compared. Image quality was assessed via blinded scoring by two radiologists and quantitative imaging metrics. Data acquisition employing sparse radial sampling with a gradient-recalled-echo acquisition and constrained iterative reconstruction (temporal resolution up to 135 ms per slice) appeared to provide a reasonable tradeoff between imaging speed and quality. This real-time MRI method effectively reduced streaking artifacts arising from data undersampling and enabled the derivation of quantitative measures pertinent to evaluating dynamic carpal instability.

Using a kidney pump to perfuse a free filet flap for reconstruction after hemipelvectomy: A case report

Long ischemia times adversely affect free flap survival, and large muscle flaps are particularly vulnerable. Hypothermic machine perfusion (HMP) is a well‐established method of organ preservation, and recent literature has detailed the use of HMP to extend free flap ischemia times, predominantly in the laboratory setting. One limitation in the study and adoption of free flap HMP has been the availability of standardized perfusion machinery, as thus far institutions have built their own devices. We present a case of a 75‐year‐old woman with dedifferentiated chondrosarcoma of her right proximal femur. She underwent a “spare parts” surgery using a filet flap from her lower leg. Due to an obligate long ischemia time between flap harvest and revascularization, a kidney transplant perfusion pump was used to flush and cool the flap. After completion of the disarticulation, free tissue transfer proceeded successfully. The patient had an uncomplicated post‐operative course until developing a local recurrence at three months post‐resection. We believe that the perfusion technology already created for solid organ transplant will have expanding indications in the future of free tissue transfer and limb replantation.