Comparison of gait after total ankle arthroplasty and ankle arthrodesis.

BACKGROUND: Prior studies reported improved gait after total ankle arthroplasty and better parameters of gait than those reported in earlier studies of patients after ankle arthrodesis. However, there are very limited data prospectively evaluating the effects on gait after ankle arthroplasty compared with ankle arthrodesis. Controversy remains regarding the relative advantages and disadvantages of these 2 treatments and especially the differences in function between them. METHODS: We performed a prospective study involving 28 patients with posttraumatic and primary ankle osteoarthritis and a control group of 14 normal volunteers. We compared gait in 14 patients who had undergone ankle arthrodesis with the gait of 14 patients who had ankle arthroplasty preoperatively and at 1 year postoperatively. Three-dimensional gait analysis was performed with a 12-camera digital-motion capture system. Temporospatial measurements included stride length and cadence. The kinematic parameters that were measured included the sagittal plane range of motion of the ankle and the coronal plane range of motion of the ankle. Double force plates were used to collect kinetic parameters such as ankle coronal and plantar flexion-dorsiflexion moments and sagittal plane ankle power. Center of pressure (CoP) and its progression in gait cycle were calculated. RESULTS: Baseline parameters showed comparability among the treatment and control groups. Temporospatial analysis, using time as the main effect, showed that compared with ankle arthrodesis, patients with total ankle arthroplasty had higher walking velocity attributable to both increases in stride length and cadence as well as more normalized first and second rockers of the gait cycle. Kinematic analysis, using time and intervention as the main effects, showed that patients who had ankle arthroplasty had better sagittal dorsiflexion (P = .001), whereas those undergoing ankle arthrodesis had better coronal plane eversion (P = .01). Neither ankle arthrodesis nor arthroplasty altered the CoP progression during stance phase. Total ankle arthroplasty produced a more symmetrical vertical ground reaction force curve, which was closer to that of the controls than was the curve of the ankle arthrodesis group. CONCLUSIONS: Patients in both the arthrodesis and arthroplasty groups had significant improvements in various parameters of gait when compared with their own preoperative function. Neither group functioned as well as the normal control subjects. Neither group was superior in every parameter of gait at 1 year postoperatively. However, the data suggest that the major parameters of gait after ankle arthrodesis in deformed ankle arthritis are comparable to gait function after total ankle arthroplasty in nondeformed ankle arthritis. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Use of a geometric formula to improve the radiographic correction achieved by the scarf osteotomy.

BACKGROUND: Many procedures for hallux valgus treatment have high recurrence rates, often related to operative considerations such as accuracy of deformity correction, soft tissue balancing and sesamoid alignment. Inadequate distal metatarsal-articular angle (DMAA) correction is common with uni- and bi-planar osteotomies which principally address the inter-metatarsal angle (IMA). The scarf osteotomy is a tri-planar osteotomy which corrects the DMAA and IMA, thereby achieving a more anatomical correction and potentially reducing the recurrence rate. Our hypothesis was that by controlling the length and relative proximal and distal translations of the scarf with a geometric formula, more accurate correction of the IMA and DMAA is possible. METHODS: A formula was generated to determine the specific adjustments required to correct the deformity. A prospective trial was performed to assess the accuracy of this formula. Thirty-four adult patients were enrolled in the study. Seventeen patients underwent a standard scarf procedure; 17 were operated on using the corrections prescribed by the formula. RESULTS: Hallux valgus angle (HVA), IMA and DMAA corrections improved with the formula (p = 0.036, p = 0.049, and p = 0.006, respectively). Patient and procedure selection has changed in our unit as a result of this study, which identified some preoperative deformities as beyond the capabilities of the scarf procedure. CONCLUSION: The formula allows precise, reproducible, anatomical correction of IMA and DMAA deformities. The degree of correction attainable with the scarf is dependent on the first metatarsal width and the preoperative deformities. The formula highlighted the limitations of the scarf, thereby aiding in appropriate patient and procedure selection.

Definition of coordinate system for three-dimensional data analysis in the foot and ankle.

BACKGROUND: Three-dimensional data is required to have advanced knowledge of foot and ankle kinematics and morphology. However, studies have been difficult to compare due to a lack of a common coordinate system. Therefore, we present a means to define a coordinate frame in the foot and ankle and its clinical application. MATERIALS AND METHODS: We carried out ten CT scans in anatomically normal feet and segmented them in a general purpose segmentation program for grey value images. 3D binary formatted stereolithography files were then create and imported to a shape analysis program for biomechanics which was used to define a coordinate frame and carry out morphological analysis of the forefoot. RESULTS: The coordinate frame had axes standard deviations of 2.36 which are comparable to axes variability of other joint coordinate systems. We showed a strong correlation between the lengths of the metatarsals within and between the columns of the foot and also among the lesser metatarsal lengths. CONCLUSION: We present a reproducible method for construction of a coordinate system for the foot and ankle with low axes variability. CLINICAL RELEVANCE: To conduct meaningful comparison between multiple subjects the coordinate system must be constant. This system enables such comparison and therefore will aid morphological data collection and improve preoperative planning accuracy.

Routine patellar resurfacing using an inset patellar technique.

The management of the patella in total knee arthroplasty still causes controversy. Whether or not to resurface the patella in primary total knee arthroplasty remains unclear. In this study we examined 220 consecutive total knee replacements, by a single surgeon, where the patella was routinely resurfaced using the inset technique. All patellae were suitable for resurfacing. Patellar thickness was not altered in 54.5% of patellae. In 97.2% the patella was within 2 mm of the original thickness. There were no significant complications. In this study we have found that the inset technique of patella resurfacing in total knee replacement is a simple and safe resurfacing procedure.

Pseudo-aneurysm of the lateral circumflex femoral artery after femoral neck fracture - A case report.

Only one case of injury of the lateral circumflex femoral artery secondary to a femoral neck fracture has been reported. We present a second case of this rare injury. A 59-year-old gentleman fell from an embankment, from approximately two meters in height, while landscaping and landed onto his left side. He suffered immediate pain in his left hip and was unable to weight bear. X-ray demonstrated a Garden II left femoral neck fracture. Within 24 of the injury, he underwent percutaneous internal fixation of his left hip using partially threaded cannulated screws. Two days post operatively, the patient described pain in his groin. X-ray was satisfactory and the pain was attributed to the fracture and subsequent surgery. However, this pain persisted, worsened and warranted further investigation. A doppler ultrasound, followed by a CT angiogram, confirmed a pseudoaneurysm of the lateral circumflex femoral artery which was treated with embolisation by the vascular surgery service. This relieved the patient's discomfort immediately. This is the second reported case of pseudo-aneurysm of the lateral circumflex femoral artery secondary to a femoral neck fracture.

A patient-specific numerical model of the ankle joint for the analysis of contact pressure distribution.

A patient-specific numerical model of the ankle joint has been developed using open-source software with realistic material properties that mimics the physiological movement of the foot during the stance phase of the gait cycle. The patient-specific ankle geometry has been segmented as a castellated surface using 3DSlicer from the computed tomography image scans of a subject with no congenital or acquired pathology; subsequently, the bones are smoothed, and cartilage is included as a uniform thickness extruded layer. A high-resolution Cartesian mesh has been generated using cfMesh. The material properties are assigned in the model based on the CT image Hounsfield intensities and compared to a sandwich-based material model. Gait data of the same subject was obtained and used to relatively position the tibia, talus, and calcaneus bones in the model. The stance phase of the gait cycle is simulated using a cell-centred finite-volume method implemented in open-source software OpenFOAM. The predicted peak contact pressures occur in the range of 4.85-5.53 MPa with average pressures in the range of 1.56-1.95 MPa, and the contact area ranges between 429 and 707.8 mm2 for the entire stance phase with the mid-stance phase predicting the maximum contact area. These predictions are in agreement with results from the literature. The effect of arthritis on the contact characteristics of the ankle joint has also been examined. A concentrated increase in pressure was predicted that could be manifested as pain, thereby leading to reduced motion in the ankle. The model, with continued development, has the capability to understand the effect of joint degradation and furthermore, could help provide a tool to predict the efficiency of therapeutic surgical procedures as well as guide the development of next generation ankle prostheses. The work would be made available in the University College Dublin depository (https://github.com/laxmimurali/anklejoint) as well as research gate once the article has been published.

Do pain referral patterns determine patient outcome after total hip arthroplasty?

Quality of life outcome and patient satisfaction after total hip arthroplasty are complex phenomena and many confounding determinants have been identified. Degenerative disease of the hip joint may present with variable patterns of pain referral in the lower limb. However the effect of varied preoperative pain referral patterns on patient outcome and satisfaction after total hip arthroplasty has not previously been examined. From 2000 to 2003, 236 eligible patients scheduled to undergo primary total hip arthroplasty were prospectively enrolled. The principal pain referral pattern (as hip, thigh or knee) was identified in all patients. Health related quality of life (HRQOL) was examined using the Harris Hip score (HHS), the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and the 36-Item Short-Form Health Survey (SF-36) pre-operatively, 1 year and 2 years postoperatively and with the HHS at 3 months postoperatively. All patients were followed up for a minimum of 2 years. The frequency of the pain referral distributions were; hip pain 41%, knee pain 32% and thigh pain 27%. Patients in all groups were comparable preoperatively with respect to age, HHS, and both mean and domain specific WOMAC and SF-36 scores. The mean duration of symptoms was significantly greater in patients with knee pain when compared to the remaining two pain patterns. All patients demonstrated improvements in HHS, SF-36 and WOMAC scores after surgery. At all times postoperatively there were significant differences in mean HHS and mean and domain specific WOMAC and SF-36 scores between patients with hip or thigh pain and those with knee pain (p < 0.001). While notable, differences between hip and thigh pain were not as consistent however. Based on these findings, it appears that pre-operative pain referral patterns of hip arthritis are among the determinant factors for patient outcome and satisfaction after total hip arthroplasty, as measured using validated HRQOL scoring systems.

Arthrodesis of the first metatarsophalangeal joint using a dorsal titanium contoured plate.

BACKGROUND: Arthrodesis of the first metatarsophalangeal joint (MTPJ) is used to treat a variety of foot pathologies. Numerous methods of internal fixation and bone end preparation have been reported. In an effort to bring together the best features of the various internal fixation devices, a low-profile contoured titanium plate (LPCT) using a compression screw was designed to be used with a ball-and-socket bone end preparation. A prospective study was carried out to determine the efficacy of this technique. METHODS: First MTPJ arthrodesis using an LPCT was done in 12 patients (10 women and two men) either as an isolated procedure (seven patients) or in conjunction with other forefoot procedures (five patients). The changes in the level of pain and activities of daily living were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) hallux score and the Short-Form 36 (SF-36) score. Time to bone union also was assessed. Mean followup was 18 months (+/-6 months). RESULTS: Statistically significant increases in the AOFAS hallux score and the SF-36 score were noted (p = .002 and .001, respectively). All radiographs showed bone union at 6 weeks and an appropriate degree of hallux dorsiflexion in relation to the first metatarsal (20 to 25 degrees). CONCLUSION: The combination of the LPCT plate and a ball-and-socket bone-end preparation has both operative and biomechanical advantages over other fixation techniques. This combination ensures that the anatomical length of the first ray is only minimally shortened and the angle of plantarflexion of the first metatarsal is maintained, resulting in preservation of medial column stability and a better functional result.

Flexor hallucis longus tendon transfer: evaluation of postoperative morbidity.

Clinical and pedobarograph evaluation was performed on 16 patients following flexor hallucis longus (FHL) tendon transfers to determine the resulting morbidity due to the loss of FHL function. All patients underwent FHL tendon transfer for either chronic tendon Achilles rupture or chronic Achilles tendinosis. Clinical evaluation of hallux function was performed using the American Orthopaedic Foot and Ankle Society (AOFAS) hallux metatarsophalangeal-interphalangeal scale, the SF-36 score, and a clinical questionnaire to assess alteration in the clinical function of the hallux during activities of daily living. Pedobarography was carried out using the Musgrave pedobarograph system to detect changes in forefoot loading in comparison to the contralateral normal foot. Fourteen of the 16 patients scored maximally on the hallux metatarsophalangeal-interphalangeal scale and none of the patients noticed functional weakness of the hallux during activities of daily living at a mean follow-up of 43.6 months (range, 5-120 months). Pedobarograph readings showed a trend toward reduction in peak pressure loading on the distal phalanx, but this was not significant for the numbers of patients studied. There was no significant increase in loading of the first or second metatarsophalangeal joints to suggest that transfer metatarsalgia may complicate FHL tendon transfer. According to the results of the study morbidity from FHL transfer should be clinically insignificant.

Radiofrequency ablation of bone with cooled probes and impedance control energy delivery in a pig model: MR imaging features.

PURPOSE: To determine the coronal marrow ablation length and detect cortical thinning after radiofrequency ablation (RFA) of bone in a pig model. MATERIALS AND METHODS: Twelve pigs underwent RFA with a 1- or 2-cm single internally cooled electrode placed at the mid-diaphyseal point of their long bones at 1, 7, or 28 days before euthanasia. Twelve minutes of impedance control radiofrequency energy was delivered at maximum output from a 200-W generator. Pigs were imaged with axial and coronal turbo spin-echo (SE) T1- and T2-weighted frequency-selective fat suppression sequences by using spectral presaturation with inversion recovery (SPIR). A radiologist blinded to the timing of the treatment and the results of other imaging sequences measured the coronal ablation zone length and cortical thickness. The pigs were euthanized, and the ablated bone underwent histologic examination. RESULTS: At SPIR imaging, the zone of marrow ablation was defined as an area of low signal intensity surrounded by a high-signal-intensity band. At T1-weighted imaging, the zone of marrow ablation was defined as a heterogeneously isointense area surrounded by a low-signal-intensity band. The mean (+/-standard deviation) coronal marrow ablation zone measurement with SPIR imaging at 28 days was 47 mm +/- 9 (range, 34-73 mm) for the 1-cm electrode and 51 mm +/- 7 (range, 33-67 mm) for the 2-cm electrode. Two humeral fractures occurred at 21 and 28 days after therapy. Thinning of the cortex adjacent to the electrode insertion site was identified in the humeral group only. CONCLUSION: The change in the marrow signal intensity with impedance-controlled RFA is larger than that reported for temperature-controlled protocols. RFA leads to bone weakening.