Citations

Aberrant connectivity is implicated in many neurological and psychiatric disorders, including Alzheimer’s disease and schizophrenia. However, other than a few disease-associated candidate genes, we know little about the degree to which genetics play a role in the brain networks; we know even less about specific genes that influence brain connections. Twin and family-based studies can generate estimates of overall genetic influences on a trait, but genome-wide association scans (GWASs) can screen the genome for specific variants influencing the brain or risk for disease. To identify the heritability of various brain connections, we scanned healthy young adult twins with high-field, high-angular resolution diffusion MRI. We adapted GWASs to screen the brain’s connectivity pattern, allowing us to discover genetic variants that affect the human brain’s wiring. The association of connectivity with the SPON1 variant at rs2618516 on chromosome 11 (11p15.2) reached connectome-wide, genome-wide significance after stringent statistical corrections were enforced, and it was replicated in an independent subsample. rs2618516 was shown to affect brain structure in an elderly population with varying degrees of dementia. Older people who carried the connectivity variant had significantly milder clinical dementia scores and lower risk of Alzheimer’s disease. As a posthoc analysis, we conducted GWASs on several organizational and topological network measures derived from the matrices to discover variants in and around genes associated with autism ( MACROD2 ), development ( NEDD4 ), and mental retardation ( UBE2A ) significantly associated with connectivity. Connectome-wide, genome-wide screening offers substantial promise to discover genes affecting brain connectivity and risk for brain diseases.

Intramedullary tibiotalocalcaneal arthrodesis (IMTCA) is an increasingly used procedure for salvage of complex hindfoot and ankle disorders. 1 , 2 To avoid injury to vital plantar neurovascular structures, it is important to begin with an appropriate insertion site during retrograde IMTCA. We use a simple, reproducible method to determine this site based on anatomic landmarks.

An intramedullary fixation device was devised by the senior author (K.A.J.) to use in conjunction with a previously described method for tibiotalocalcaneal arthrodesis. Satisfactory results were obtained in approximately 87% of the initial 30 patients; union was radiographically or clinically evident in all but two patients. Many of these patients had been offered or were considering below the knee amputation; only two ultimately chose this reconstructive option at a follow-up that ranged from 4 to 27 months.

Nineteen patients underwent surgical synovectomy and debridement for the clinical diagnosis of stage I posterior tibial tendon (PTT) dysfunction. Stage I PTT dysfunction is characterized by pain and swelling along the medial aspect of the ankle. Fourteen patients (74%) reported complete relief of pain, 3 patients (16%) reported minor pain, and 1 patient (5%) had moderate pain, and 1 (5%) had continued severe pain. Sixteen (84%) of the patients subjectively reported being “much better” and had a return of function of the PTT, as evidenced by their ability to perform a single limb-heel-rise test. Two patients (10%) underwent subtalar arthrodesis for progressive foot deformity and continued pain. Based on these results, surgical release, tenosynovectomy, and debridement are recommended for the treatment of stage I PTT dysfunction.

The chevron osteotomy for hallux valgus was modified by addition of screw fixation and change of the osteotomy angle. Thirty-six patients underwent this modified osteotomy. All had mild to moderate symptomatic hallux valgus deformities. No other forefoot procedures were performed. Standing radiographs were taken before surgery, at 1 month after surgery, and, for the 15 patients who returned for long-term follow-up, at 1 year or more after surgery. Overall, 35/42 procedures were rated as satisfactory without reservations and 7 were rated as satisfactory with mild reservations. All patients stated that they had some improvement in their preoperative symptoms, which included pain, cosmetic concerns, and shoe wear difficulties. Radiographically, none of the capital fragments displaced and there were no malunions, nonunions, nor evidence of avascular necrosis. The average metatarsophalangeal-1 angle improved 8° and the average intermetatarsal 1–2 angle improved 4°. This modification is relatively simple, increases stability, and allows early weightbearing. In our experience, the modified chevron osteotomy has been a very reliable procedure for mild to moderate symptomatic hallux valgus deformity.

The Rochester bone trephine is a useful instrument for performing small joint arthrodesis in the foot. The technique involves harvesting a dowel graft from the iliac crest and then inserting the graft into a recipient bed across the small joints in the foot. Minimal surgical trauma and patient discomfort result from this technique. Three cases are presented to illustrate the usefulness and diversity of this system.

Thirteen patients (14 feet) were treated for mild rheumatoid forefoot deformities with lesser toe partial proximal phalangectomies and partial syndactylizations. Eleven patients (85%) were reviewed at an average of 8 years postoperatively. The results were completely satisfactory in four patients, satisfactory with minor reservations in three patients, satisfactory with major reservations in one patient, and unsatisfactory in three patients. The major cause of reservations and lack of satisfaction was metatarsalgia. Seven patients (64%) reported that their activities were limited by intermittent metatarsalgia. Four patients (36%) considered the cosmetic appearance of the forefoot to be unsatisfactory. All but one patient required some form of shoewear modification. Based on this study, we believe the indications for this procedure are limited. These include rheumatoid patients with mild forefoot deformities without significant metatarsalgia or ongoing disease who have failed nonoperative treatment. Relative contraindications to this operation appear to include the recent onset of rheumatoid arthritis, active disease, significant metatarsalgia, and strong cosmetic concerns regarding outcome. In borderline clinical decisions that involve whether or not to leave or excise the lesser metatarsal heads, they probably should be excised to decrease late metatarsalgia.

The effects of shoe wear, custom-made inserts, patellar tendon-bearing (PTB) braces, and extra-padded PTB braces on load transmission to neuroarthropathic (Charcot) feet of six diabetic patients were assessed. A PTB brace with a free ankle and an extradepth shoe without external modifications was used. Four distinct anatomical regions were evaluated by an in-shoe technique measuring vertical force. The mean peak force transmitted to the entire foot was higher in the affected than in the unaffected extremity barefoot and shod. The mean peak forces under the midfoot were higher for the affected than for the unaffected extremity for all tested circumstances. In the affected foot, use of the standard PTB brace reduced mean peak force to the entire foot by 15%. Adding extra padding to the brace decreased the mean peak force 32%. The effect of padding on vertical load transmission was greatest for patients who had worn the brace the longest. For the patients who had worn it longer than average, the addition of padding decreased the mean peak force to the entire foot by 19%, to the hindfoot by 37%, and to the midfoot by 20%. Clinical Relevance: In this preliminary study, we found that a properly fitted PTB brace can reduce load transmission to the Charcot foot. Specifically, load transmission was reduced to the hindfoot, but not to the midfoot or forefoot. Based on these results, we cannot recommend its use to reduce vertical force transmission to the Charcot midfoot or forefoot. Long-term PTB brace use, especially in the limited weightbearing patient, should be regularly adjusted to ensure adequate brace fit.

The objective documentation of foot function before and after therapeutic intervention will be greatly enhanced by the utilization of devices capable of measuring dynamic foot pressure distribution. Efforts to develop this technology date back to the late 19th century, but only with recent advances in computers has it been possible to produce quantitatively accurate high resolution foot pressure distribution with high sampling rates and easily interpreted graphic displays. Over the years, a variety of methods have been employed to study foot pressure. Many of these techniques have already improved our understanding of the foot and its function, and have had an impact on the way we practice. Effective clinical utilization of these new investigative tools depends on an understanding of their scientific basis, capabilities and limitations.

Between 1978 and 1984, 20 adolescent patients underwent 35 chevron osteotomies of the first metatarsal for correction of painful hallux valgus. After an average follow-up of 64 months, 85% of the patients expressed overall satisfaction. The cosmetic effect was the most satisfactory result (90%), followed by relief of pain (85%) and lack of limitations in footwear (65%). Radiographic evaluation did not seem to correlate with the final clinical result. The chevron osteotomy is a reasonable operative procedure for correction of hallux valgus in adolescents.