Introduction:

Peroneal muscle weakness is a common pathology in foot and ankle surgery. Polio, charcot marie tooth disease and spina bifida are associated with varying degrees of peroneal muscle paralysis. Tibialis Posterior, an antagonist of the peroneal muscles, becomes pathologically dominant, causing foot adduction and contributes to cavus foot posture. Refunctioning the peroneus muscles would enhance stability in toe off and resist the deforming force of tibialis posterior. This study determines the feasibility of a novel tendon transfer between peroneus longus and gastrocnemius, thus enabling gastrocnemius to power a paralysed peroneus tendon.

Introduction: Tarsometatarsal joint (TMTJ) arthrodesis is traditionally performed through a dorsal approach and is associated with higher incidence of cutaneous nerve damage, prominent metalware and high non-union rates. It is postulated that applying fixation to the plantar (tension) side, rather than the dorsal (compression) side would create a more stable construct with higher union rates. A suitable surgical approach has not previously been described. The aim of this study is to define a plantar surgical approach to the TMTJ’s.

Methods: We dissected 10 cadaveric feet, identifying nerves, vessels, muscles and their innervation on the plantar aspect of the 1st and 2nd TMTJ’s.

Results: We found that in all specimens a plane of dissection could be created between the two terminal divisions of the medial plantar nerve between flexor digitorum brevis and abductor hallucis. Although exposure of the 1st TMTJ was relatively easy, access to the 2nd TMTJ was difficult due to its location at the apex of the transverse metatarsal arch and the overlying peroneus longus insertion. We found that the peroneus longus tendon had a variable insertion not only at the base of the 1st metatarsal but also at the medial cuneiform and the base of the 2nd metatarsal.

Discussion: This is a new surgical approach, following an internervous dissection plane. The feasibility of making an incision over the convex side of the rocker bottom deformity and the biomechanical advantage of a plantarly applied fixation device may make this an attractive surgical approach.

Introduction: The sural nerve is commonly encountered in many operations on the lateral part of the foot and ankle, such as fixation of distal fibula, 5th metatarsal and calcaneal fractures, and fusion of the subtalar or calcaneo-cuboid joints. However there is no consensus and quantitative description of the branches of sural nerve distal to the ankle in the reviewed literature. This study aims to describe these branches and quantify their relations.

Methods: The distal course of the sural nerve was dissected in 30 embalmed cadaveric limbs.

Results: A fibular branch was found in close proximity to the tip of the distal fibula in 63% of specimens. A dorsal branch at the level of the cuboid was found in 80% of specimens, however, its point of departure from the main nerve varied considerably. More distally a series of plantar branches of varying number, and at varying distances to each other was found. These branches were then described in relation to the following bony landmarks: the tip of the distal fibula, the calcaneo-cuboid joint, the tuberosity of the base the 5th metatarsal, the shaft of the metatarsal and the 5th metatarso-phalangeal joint. The distances between these landmarks were quantified using digital analysis.

Conclusion: The sural nerve has a number of previously undescribed but potentially important branches distal to lateral malleolus in the foot. Identifying these branches during surgery with relation to the various bony structures should minimise the risk of nerve injury.

Correct positioning and alignment of components during primary total knee replacement (TKR) is widely accepted to be an important predictor of patient satisfaction and implant durability. This retrospective study reports the effect of the post-operative mechanical axis of the lower limb in the coronal plane on implant survival following primary TKR.

A total of 501 TKRs in 396 patients were divided into an aligned group with a neutral mechanical axis (± 3°) and a malaligned group where the mechanical axis deviated from neutral by > 3°. At 15 years’ follow-up, 33 of 458 (7.2%) TKRs were revised for aseptic loosening. Kaplan-Meier survival analysis showed a weak tendency towards improved survival with restoration of a neutral mechanical axis, but this did not reach statistical significance (p = 0.47).

We found that the relationship between survival of a primary TKR and mechanical axis alignment is weaker than that described in a number of previous reports.

Introduction: There is limited literature available looking into circumstances surrounding the development of stress fracture of the medial and lateral malleoli after ankle replacement. We present the preliminary results of a prospective study examining the effect of ankle replacement upon local bone mineral density and the phenomenon of stress shielding.

Aim: To assess the effect of ankle replacement loading of the medial and lateral malleoli, by analysing the BMD of the medial and lateral malleoli before and after Mobility total ankle replacement.

Methodology: Ten consecutive patients undergoing Mobility total ankle replacement for osteoarthritis had pre-operative bone densitometry scans of the ankle, repeated at 6 and 12 months after surgery. The bone mineral density of a 2 cm square area within the medial malleolus and lateral malleolus was measured. The pre-operative and post-operative bone densitometry scans were compared. The relation between the alignment of the tibial component and the bone mineral density of the malleoli was also analysed.

Results: The mean preoperative BMD within the medial malleolus improved from 0.58g/cm2 to mean 6 months postoperative BMD of 0.59g/cm2 and 0.60g/cm2 at 12 months. The mean preoperative BMD within the lateral malleolus decreased from 0.40g/cm2 to a mean 6 months postoperative BMD of 0.34g/cm2. However the BMD over the lateral malleolus increased to 0.36g/cm2 at 12 months. The mean alignment of the tibial component was 88.5° varus (85° varus to 94° valgus). There was no correlation between the alignment of the tibial component and the bone mineral density on the medial malleolus (r = 0.09, p = 0.865).

Conclusion: The absence of stress shielding around the medial malleolus indicates that TAR implanted within the accepted limits for implant alignment, load the medial malleolus. However, there was stress shielding over the lateral malleolus resulting in decreased BMD in the lateral malleolus.

Outcomes following total ankle replacement (TAR) have been less favorable than hip and knee arthroplasty. The Mobility TAR is a newly introduced mobile bearing ankle prosthesis which, unlike its predecessor the Agility, does not require fusion of the tibiofibular syndesmosis which in theory should reduce the rate of early failure. No studies have been published yet reporting follow-up longer than 1 year after surgery with this prosthesis.

From June 2006 to May 2008, 50 Mobility TARs were performed in our unit. Data have been collected prospectively on all 50 patients and all have been reviewed annually since surgery. Follow up ranges from one to three years.

The mean age was 65 (range 35–79). 20 patients (40%) were male. 10 underwent additional concurrent procedures (six calcaneal osteotomies, one 1st metatarsal osteotomy, two lateral ligament reconstructions, one subtalar arthrodesis). There was one early wound breakdown which subsequently healed without causing deep infection. There were no malleolar fractures. In two prostheses the talar component has subsided over two years resulting in painful loosening. Interestingly both these patients had postraumatic osteoarthritis with a fibular malunion. Both have been listed for revision to arthrodesis. One further patient has a loose talar component without subsidence and is awaiting exploration with a view to revision. There was one deep infection presenting at 18 months. One further patient reports continued hindfoot pain, thought to be from the subtalar joint and is being worked up for arthrodesis. The mean American Orthopaedic Foot and Ankle Society scores (scale 10–100) increased from 30 to 69 scores following surgery.

TAR using the Mobility prosthesis gives good early clinical results. Further follow-up studies are required to see if this performance is maintained in the long term.

There is limited literature available looking into circumstances surrounding the development of stress fracture of the medial and lateral malleoli after ankle replacement. We present the preliminary results of a prospective study examining the effect of ankle replacement upon local bone mineral density and the phenomenon of stress shielding.

We aimed to assess the effect of ankle replacement loading of the medial and lateral malleoli, by analysing the Bone Mineral Density (BMD) of the medial and lateral malleoli before and after Mobility total ankle replacement.

Ten consecutive patients undergoing Mobility total ankle replacement for osteoarthritis had pre-operative bone densitometry scans of the ankle, repeated at 6 months after surgery. The bone mineral density of a 2 cm square area within the medial malleolus and lateral malleolus was measured. The pre-operative and postoperative bone densitometry scans were compared. The relation between the alignment of the tibial component and the bone mineral density of the malleoli was also analysed.

The mean preoperative BMD within the medial malleolus improved from 0.57g/cm2 to mean 6 months postoperative BMD of 0.62g/cm2. The mean preoperative BMD within the lateral malleolus decreased from 0.39g/cm2 to a mean 6 months postoperative of 0.33g/cm2. The mean alignment of the tibial component was 88.50 varus (range 850 varus to 940 valgus). However, there was no correlation between the alignment of the tibial component and the bone mineral density on the medial malleolus (r = 0.09, p = 0.865).

The absence of stress shielding around the medial malleolus indicates that ankle replacements implanted within the accepted limits for implant alignment, load the medial malleolus. However, there was stress shielding over the lateral malleolus resulting in decreased BMD in the lateral malleolus.

This study evaluates the effect of lower limb post-operative mechanical axis on the long term risk of revision surgery following primary total knee arthroplasty (TKA). The study is relevant because many recent clinical trials have evaluated the optimal surgical technique for accurately aligning components in TKA, despite little evidence that alignment may effect the long-term clinical outcome.

The data used in this study was collected prospectively as part of a randomized control trial comparing the long term survival of cemented versus uncemented TKA. The trial included 501 press-fit condylar posterior cruciate ligament-retaining prostheses performed by the senior author (PJG) or under his direct supervision. The post-operative mechanical axis alignment of the lower limb was measured following TKA using standard AP weight-bearing long leg alignment radiographs. A comparison was made between a well-aligned group with a mechanical axis alignment within 3° of neutral; and a poorly-aligned group whose mechanical axis alignment deviated greater than 3° from neutral. Survival analysis used revision surgery, with exchange of any of the three originally inserted components (femoral, tibial, polyethylene insert), as the endpoint.

There was no loss to follow-up in this study. The minimum follow-up of TKAs in this study was 5.8 years. In the population of TKAs that were followed up at 10 years, 6% (17/270) required revision surgery. There was a significant difference in the rate of revision surgery between the well-aligned group 5% (11/227) and the poorly-aligned group 14% (6/43 p< 0.05)

This study shows that post-operative lower limb mechanical axis alignment is an important determinant of the need for revision surgery at 10 years. Surgeons performing TKA should pay particular attention to the placement of the tibial and femoral components, so that a mechanical axis within 3° of neutral is achieved.

Introduction: There is limited literature looking into the circumstances surrounding the development of stress fractures of the medial and lateral malleoli after ankle replacement. We present the preliminary results of a prospective study examining the effect of total ankle replacement (TAR) upon local bone mineral density (BMD) and the phenomenon of stress shielding.

Aim: To assess the effect of TAR loading othe medial and lateral malleoli, by analysing the BMD of the medial and lateral malleoli before and after Mobility TAR.

Methodology: Ten consecutive patients undergoing Mobility total ankle replacement for osteoarthritis had pre-operative bone densitometry scans of the ankle, repeated at 6 and 12 months after surgery. The bone mineral density of a 2 cm square area within the medial and lateral malleoli was measured. The pre-operative and post-operative bone densitometry scans were compared. The relation between the alignment of the tibial component and the bone mineral density of the malleoli was also analysed.

Results: The mean preoperative BMD within the medial malleolus increased from a mean of 0.57g/cm2 to 0.58g/cm2 at six months and 0.60g/cm2 at 12 months postoperatively. The mean preoperative BMD within the lateral malleolus decreased from 0.39g/cm2 to 0.34g/cm2 at six months postoperatively. However the BMD over the lateral malleolus increased to 0.356g/cm2 at 12 months. The mean alignment of the tibial component was 88.50 varus (range 850 varus to 940 valgus). There was no correlation between the alignment of the tibial component and the bone mineral density on the medial malleolus (r = 0.09, p = 0.865).

Conclusion: The absence of stress shielding around the medial malleolus indicates that ankle replacements implanted within the accepted limits for implant alignment, load the medial malleolus. However, there was stress shielding over the lateral malleolus resulting in decreased BMD in the lateral malleolus.

Introduction: There is limited literature available looking into circumstances surrounding the development of stress fracture of the medial and lateral malleoli after ankle replacement. We present the preliminary results of a prospective study examining the effect of ankle replacement upon local bone mineral density and the phenomenon of stress shielding.

Aim: To assess the effect of ankle replacement loading of the medial and lateral malleoli, by analysing the BMD of the medial and lateral malleoli before and after Mobility total ankle replacement.

Methodology: Ten consecutive patients undergoing Mobility total ankle replacement for osteoarthritis had pre-operative bone densitometry scans of the ankle, repeated at 6 months after surgery. The bone mineral density of a 2 cm square area within the medial malleolus and lateral malleolus was measured. The pre-operative and post-operative bone densitometry scans were compared. The relation between the alignment of the tibial component and the bone mineral density of the malleoli was also analysed.

Results: The mean preoperative BMD within the medial malleolus improved from 0.57g/cm2 to mean 6 months postoperative BMD of 0.62g/cm2. The mean preoperative BMD within the lateral malleolus decreased from 0.39g/cm2 to a mean 6 months postoperative BMD of 0.33g/cm2. The mean alignment of the tibial component was 88.50 varus (range 850 varus to 940 valgus). However, there was no correlation between the alignment of the tibial component and the bone mineral density on the medial malleolus (r = 0.09, p = 0.865).

Conclusion: The absence of stress shielding around the medial malleolus indicates that ankle replacements implanted within the accepted limits for implant alignment, load the medial malleolus. However, there was stress shielding over the lateral malleolus resulting in decreased BMD in the lateral malleolus.

Introduction: The Scarf osteotomy for the treatment of hallux valgus is achieving popularity, but no comparative study has proven the efficacy of this procedure over other first metatarsal osteotomies.

We present a retrospective comparative review of the radiological outcomes of Chevron and Scarf with Akin osteotomy in the treatment of hallux valgus.

Materials and Methods: The radiological outcomes of 40 first metatarsal osteotomies, 20 Chevron and 20 Scarf with Akin are presented. The radiological parameters studied included hallux valgus angle, hallux inter-phallangeus, intermetatarsal angle, sesamoid station and foot width.

Results: The mean post-operative hallux valgus angles (HVA’s) were: Chevron mean HVA 17.90, standard deviation 7.360, standard error 1.65. Scarf with Akin osteotomy mean HVA 9.550, standard deviation 6.60, standard error 1.4. The difference in postoperative HVA between the two operations was statistically significant (p< 0.001).

The mean post-operative intermetatarsal angles (IMA) were: Chevron mean 8.050, standard deviation 2.560, standard error 0.57. Scarf with Akin mean 7.220, standard deviation 2.56, standard error 0.57. The difference in postoperative IMA between the two groups did not achieve statistical significance.

The mean change in IMA for each was: Chevron mean increment 4.90 Standard deviation 2.290, standard error 0.51. Scarf with Akin mean increment 6.680, standard deviation 4.130, and standard error 0.88. The difference in alteration of IMA between the two groups did not achieve statistical significance.

Discussion and Conclusion: We conclude that as there was no difference in the distribution of post-op IMA for Scarf and Chevron osteotomies that the added affect of an Akin osteotomy may contribute to the Scarf to produce the better correction in hallux valgus angle.

Introduction: There is relatively little known about patient-reported health status in patients with ankle arthritis awaiting arthroplasty. This study aims to compare the preoperative health status of patients awaiting ankle, hip and knee arthroplasty.

Materials and Methods: Patients admitted for primary ankle, hip or knee arthroplasty to an NHS teaching hospital were invited to participate. Preoperative questionnaire included the WOMAC, SF-36 and self-reported height and weight providing body mass index (BMI). Comparisons of WOMAC and SF-36 data were adjusted for age, gender and BMI.

Results: A total of 2,196 patients were recruited between July 2003 and May 2007; including 35 ankle arthroplasty (TAA), 899 hip arthroplasty (THA) and 1,262 total arthroplasty (TKA) cases. There was no significant difference in age across the 3 groups but a significantly higher proportion of TAA patients were male (69 percent vs. 38 percent for THA and 43 percent for TKA, p=0.0002). BMI of the TKA patients was significantly higher than the THA patients (29.4 vs. 27.3, p< 0.0001). Multivariate analysis which adjusted for age, gender and BMI demonstrated that THA patients were significantly worse (p< 0.05) than the TKA patients on all domains except for WOMAC stiffness and the SF-36 general health and mental health domains. TAA patients were not significantly different from either group on any measure.

Conclusions: Patients awaiting TAA reported similar WOMAC and SF-36 scores as the TKA patients. Patients awaiting THA report worse pain and function related to their hip and worse SF-36 scores except for general health and mental health domains.

Aim: To validate the accuracy of the MobilityTotal Ankle Replacement alignment jig.

Method: The early radiological alignment outcomes (angles ‘A, B, C’) of 35 Mobility ankle replacements were determined from weight bearing X rays.

These radiological outcomes were compared with alignment outcomes for ‘Star’ total ankle replacement, as published by PLR Wood. (Total Ankle Replacement JBJS April 2003 85B, pg 334)

Results: Indication: osteoarthritis 25, posttraumatic osteoarthritis 6, rheumatoid arthritis 4.

32/35 Angle A were within the published accepted range (850–950).

No statistical difference between the distribution of angle A, B and C and the means for A, B and C for the published results.

Discussion: Results for angle B are skewed toward the upper limit of the current accepted range (800–900). The author (MSS) attempts to reproduce this, to place the anterior margin of the tibial component on subchondral bone.

A lower angle B positions the implant on metaphyseal bone with a risk of subsidence. Comparing Angle B with a modified acceptable range (850–950) 31/35 fell in the new range.

Conclusion: Early radiological alignment for Mobility is reproducible and compares favourably with published data.