The use of a 3D printed titanium implant for arthrodesis in the management of large osseous defects in the ankle.

BACKGROUND: Large osseous defects (LOD) in the ankle occur because of multiple aetiologies. Advancement in 3-dimensional (3D) printing technologies has led to the use of custom implants and instrumentation their management. A 3D printed patient-specific porous titanium cage which allows for peripheral osteo-integration and autogenous bone-grafting could be an ideal implant in these cases. METHODS: Retrospective review of a multi-centre, multi-surgeon consecutive cohort of patients requiring either TTC or AA for a large osseous defect between June 2019 - August 2020. A custom titanium prosthesis was 3D-printed according to CT measurements for implantation. RESULTS: Mean follow up was 19.5 months (range 12-24 months). Plain radiographs and CT scans at 12 months confirmed osseointegration (stability) in 11of 13 patients (84%). Two patients developed late infection, one requiring revision surgery. CONCLUSIONS: 3D-Printed titanium implants in the management of LODs in the ankle offer a comparable success rate to other reported procedures, with unlimited geometric possibilities in the design allowing for accurate length correction. Their structural stability may offer an advantage over conventional bone graft techniques and limits the amount of bone-graft required. LEVELS OF EVIDENCE: LOE III.

Tumor induced osteomalacia from a peripheral mesenchymal tumour of the foot.

Tumour induced osteomalacia (TIO) is a rare condition caused by peripheral mesenchymal tumours (PMT) which produce fibroblast-growth factor 23 (FGF23). FGF23 inhibits renal phosphate reabsorption leading to vitamin D resistant osteomalacia. The rarity of the condition and difficulty with isolating the PMT make diagnosis difficult, with delayed treatment leading to significant patient morbidity. We present a case of PMT of the foot with TIO, with a discussion on diagnosis and treatment.

Reliability of the Radiographic Measurement of the Hallux Interphalangeal Angle.

BACKGROUND: The hallux valgus interphalangeus (HVI) deformity has a common association with hallux valgus and hallux rigidus. The HVI is formed by the angle between the long axes of the proximal and distal phalanges. The normal value for this angular deformity in the coronal plane is less than 10°. The aim of this study was to analyze the intra- and inter-observer reliability of measuring the interphalangeal angle by orthopaedic surgeons. This study is the first study to evaluate specifically the reliability and reproducibility of measuring the HVI angle. METHODS: Twenty-one X-ray prints of weightbearing feet constituted a set. Sixteen qualified orthopaedic surgeons were asked to measure the HVI angle of all 21 X-ray images in the set. Three randomized sets were sent to each evaluator at 4-week intervals. After all 3 sets were measured, data were retrieved and statistically analyzed to determine the inter- and intraobserver variability and reliability in the measurement of the HVI angle. Reproducibility of the HVI measurement was assessed using 3 categories, which included the ability to measure the same angle 3 times and achieve: 3° or less, 5° or less, and more than 5° variation. RESULTS: The intraobserver reliability was found to be 5° or less in 85.2% of participants and the interobserver reliability was 81.2%. The researcher did not find significant correlation between the surgeons' level of experience with regard to the reliability of measuring the HVI angle. CONCLUSION: The inter- and intraobserver reliabilities of measuring the HVI angle is 81.2% and 85.2%, respectively. The level of experience of the surgeon does not improve this reliability. LEVELS OF EVIDENCE: Level II.

A new lesser metatarsophalangeal joint replacement arthroplasty design - in vitro and cadaver studies.

BACKGROUND: Isolated degenerative joint disease and/or Freiberg's infraction of the lesser metatarsophalangeal joint, although not frequent may become debilitating in the younger individual. Currently, once conservative management fails, the mainstay of treatment is debridement and excision-interposition arthroplasty. Replacement arthroplasty has been ineffective in the long term as the joints are subject to severe repetitive fatigue loading over small articulating surfaces through a wide range of motion. This is an in vitro and cadaver study of a new design replacement arthroplasty developed by the senior author. The aim of this study is to evaluate this novel replacement arthroplasty of the lesser metatarsophalangeal joint in a laboratory setting and cadaver implantation. METHODS: This three-component mobile bearing device is made of titanium and high density polyethylene which evolved over 4 years. It was subjected to 5,000,000 cycles in a laboratory under physiological and excessive forces to assess resistance to fatigue failure and wear pattern of the polyethylene liner. Following these tests, it was implanted in 15 fresh frozen cadavers at various stages of its development, during which the surgical technique was perfected. Range of motion and stability was tested using custom made instrumentation in four cadavers. The implant was inserted in a further two cadavers by an independent foot and ankle surgeon to check reproducibility. RESULTS: The device showed almost no signs of wear or surface deformation under physiological forces. The surgical technique was found to be simple and reproducible in the cadaver trial. The average dorsiflexion was 28.5° and 28.9° pre- and post-implant respectively. The average plantar flexion was 33.8° and 20.8° pre- and post- implant respectively. The joints were stable both pre- and post-operatively. Post-operative stability was objectively assessed for dorsal displacement and dorsiflexion using a 5 kgf (49 N) and was found to be excellent. CONCLUSION: This novel lesser metatarsophalangeal joint replacement arthroplasty has been developed as an option in the surgical treatment of symptomatic degenerative joint disease and/or Freiberg's infraction resistant to conservative treatment. The implant was found to be durable and resistant to wear in the laboratory testing. The cadaver studies have shown it to require minimal specialized instrumentation with good surgical reproducibility. This proof of concept study is the basis for clinical trials.

Radiographic Assessment of Relative First Metatarsal Length Following Modified Lapidus Procedure.

BACKGROUND: The modified Lapidus is a surgical procedure for managing moderate to severe hallux valgus, especially in the presence of first tarsometatarsal joint arthritis or hypermobility. It has good long-term results but reportedly can lead to transfer metatarsalgia due to inherent shortening of the first metatarsal. METHODS: A retrospective analysis of all adult patients who underwent a modified Lapidus procedure during a 3-year period was performed. Clinical notes were evaluated to look for nonunion or any other complications related to the surgery. Pre- and postoperative standard weightbearing radiographs were used to establish the relative metatarsal length (RML), intermetatarsal angle (IMA), hallux valgus angle (HVA), and distal metatarsal articular angle (DMMA). A total of 69 modified Lapidus procedures were identified, with 32 included in the study. RESULTS: The mean pre- and postoperative RMLs were -0.8 and -4.9 mm, respectively. The average RML shortening due to the procedure was -4.1 (P < .0001). The mean pre- and postoperative IMAs were 15 and 5 degrees, respectively (P < .0001). The mean pre- and postoperative HVAs were 33 and 9 degrees, respectively (P < .0001). One patient reported transfer metatarsalgia, which was attributed to elevation of the first metatarsal. CONCLUSION: We found a statistically significant degree of shortening of the relative length of the first metatarsal without any clinically significant metatarsalgia. The low rate of transfer metatarsalgia following the modified Lapidus procedure could be attributed to the sagittal plane correction and stability obtained by performing a first tarsometatarsal fusion. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Morphology of the first metatarsal head as a risk factor for hallux valgus interphalangeus.

BACKGROUND: The aetiology of hallux valgus interphalangeus (HVI) is not well understood. First metatarsophalangeal joint stability, influenced by first metatarsal head shape, may be linked to HVI. We hypothesised that first metatarsal head shape is a risk factor for HVI. No published article could be found in the literature investigating this hypothesis. METHODS: 127 standardised foot radiographs were analysed retrospectively. The hallux valgus angle (HVA) and interphalangeus angle (IPA) were measured. The first metatarsal head shape was divided into chevron, round and flat groups. Statistical analysis was then performed to investigate the relationship between first metatarsal head shape and the occurrence of HVI. RESULTS: There was no statistically significant relationship between first metatarsal head shape and the occurrence of HVI. There was however a negative relationship between HVA and HVI. CONCLUSIONS: The morphology of the first metatarsal head does not seem to be a risk factor for HVI. A known negative relationship between HVA and IPA is reinforced. LEVEL OF EVIDENCE: Level III, retrospective cohort.

Association Between Plantar Fasciitis and Isolated Gastrocnemius Tightness.

BACKGROUND: An association between plantar fasciitis and isolated gastrocnemius tightness (IGT) has been postulated in the literature; however, there have been few studies to prove this relationship. This prospective cross-sectional cohort study was aimed at determining the association between plantar fasciitis and IGT. METHODS: Three groups comprising 45 patients with plantar fasciitis (group 1), 117 patients with foot and ankle pathology other than plantar fasciitis (group 2), and 61 patients without foot and ankle pathology (group 3) were examined for the presence of IGT using the Silfverskiöld test. Statistical tests included chi-square test, Student t test, and analysis of variance. RESULTS: Of the patients, 101 (45.3%) had IGT: 36 (80%) in group 1, 53 (45.3%) in group 2, and 12 (19.7%) in group 3. The difference in IGT prevalence between the groups was statistically significant at P < .001. The prevalence of IGT was similar between acute and chronic plantar fasciitis at 78.9% and 80.6%, respectively. CONCLUSION: There was a very strong association between plantar fasciitis and IGT using group 3 as a reference. This study suggests that IGT should be actively sought out and managed in patients with plantar fasciitis. LEVEL OF EVIDENCE: Level II, cross-sectional cohort prospective study.

Schwannoma and neurofibroma of the posterior tibial nerve presenting as tarsal tunnel syndrome: review of the literature with two case reports.

We present two case reports of peripheral nerve tumors (schwannoma and neurofibroma) that presented as tarsal tunnel syndrome for many years. There has never been a report of multiple neurofibroma of the posterior tibial nerve presenting as a tarsal tunnel syndrome. Both patients were treated surgically with good outcomes.

A radiographic analysis of the contribution of hallux valgus interphalangeus to the total valgus deformity of the hallux.

BACKGROUND: The hallux valgus interphalangeus (HVI) deformity is described as rare, but improved outcomes in hallux valgus (HV) surgery is associated with its surgical correction via an Akin osteotomy. The hypothesis of this study is that HVI is common and makes a significant contribution to the total valgus deformity of the hallux (TVDH). METHODS: 285 pre-operative foot radiographs (193 with HV, 92 non-HV), utilising standardised radiographic and measurement techniques, were analysed retrospectively. The hallux valgus angle (HVA), intermetatarsal angle (IMA), interphalangeal angle (IPA) and distal metatarsal articular angle (DMAA) were measured. The TVDH was calculated as the sum of the HVA and IPA. RESULTS: 163 (57.2%) of the study population were Caucasian, 119 (41.8%) African and 3 Indian (1.0%). 236 (82.8%) of the population was female. There was a statistically significant difference in the proportion of abnormal IPA in the Caucasian population 112 (68.7%) compared to the proportion of abnormal IPA in the African population 64 (53.8%), p=0.01. The average contribution of the IPA to the TVDH across the whole study population was a mean (SD) of 37.9% (21.2). The average contribution of IPA to TVDH was greater in feet without HV (58.0%) when compared to feet with HV (28.3%). HVI is common, particularly in Caucasians (p=0.01) and makes a significant contribution to the TVDH (p<0.01). The contribution to the TVDH is more significant in mild HV. There is an inverse relationship between the IPA and other angular measurements in the foot. CONCLUSION: HVI is a common entity. The significant contribution of the IPA to the TVDH dictates that HVI must be incorporated in management algorithms. The TVDH should replace the isolated concepts of HV and HVI. LEVEL OF EVIDENCE: Level III, retrospective cohort.

Tibialis Posterior Tendon Dislocation: A Review and Suggested Classification.

Tibialis posterior tendon dislocation is a rarely described entity that is easily missed, resulting in delayed diagnosis and treatment. A review of the English published data on the topic showed inconsistency in the reporting of injuries and surgical management techniques, leading us to describe a novel classification system to guide treatment and future reporting. We also describe a case of tibialis posterior tendon dislocation in a professional volleyball player and our surgical technique for correction, including retromalleolar groove deepening.

Isolated Subtalar Arthrodesis.

INTRODUCTION: An isolated subtalar arthrodesis through a sinus tarsi approach with cannulated screw fixation is safe, reproducible, and effective for specific hindfoot pathology in adults. STEP 1 PREOPERATIVE PLANNING: Perform a comprehensive clinical and radiographic assessment. STEP 2 PATIENT POSITIONING: Position the patient supine on the operating table with a bump under the ipsilateral hip, to internally rotate the involved leg. STEP 3 INCISION: Mark a longitudinal incision from just inferior to the tip of the lateral malleolus and extending toward the base of the 4th metatarsal. STEP 4 APPROACH: Expose the subtalar joint by reflecting the extensor digitorum brevis and protecting the peroneal tendons. STEP 5 JOINT PREPARATION: Meticulously prepare the subtalar joint using osteotomes and curets down to healthy bleeding subchondral bone. STEP 6 REDUCTION AND FIXATION: Reduce the subtalar joint into 5° of valgus and fix it with cannulated screws. STEP 7 WOUND CLOSURE: Meticulously close the wound in layers and place the lower leg in a well-padded plaster back slab with the ankle in a neutral position. STEP 8 POSTOPERATIVE CARE: The operatively treated leg is kept immobilized and non-weight-bearing for the first 6 weeks. RESULTS: Numerous retrospective articles have reported high fusion rates and good functional outcomes after isolated subtalar arthrodesis, for all indications.