Wrist & Hand

Immobilization and pain control following volar plating

Revisions for failed trapeziometacarpal joint arthritis surgery

The existence of a number of accepted surgical options for a given indication suggests both variation in practice and the absence of a ‘clear winner’. Nowhere is this truer than in surgical treatment of the degenerate trapeziometacarpal joint. There is a wealth of evidence concerning the best overall treatments, which is often conflicting and leads to a wide variation in clinical practice. Trapeziectomy with or without ligament reconstruction remains the mainstay, with other arthroplasty operations also being performed. Many patients do very well following a trapeziectomy; however, if this fails, the salvage options are often somewhat difficult and yield unpredictable results. A team from Gainesville, Florida (USA) have retrospectively reviewed a cohort of 90 patients over a 20-year period undergoing revision surgery following trapeziectomy, ligament reconstruction, tendon interposition alone, haematoma arthroplasty (simple trapeziumectomy with no ligament reconstruction or interposition), or implant arthroplasty.² Of the 90 patients reported in this series, seven were excluded due to their follow-up not exceeding the minimum two years post-revision, leaving 83 patients with 86 operated thumb bases. The primary indications for revision were pain (63%), instability (6%), and pain with instability (21%). The mean time to revision surgery was two years, and at this time 18 hands had additional surgery to the metacarpophalangeal joint (a capsulodesis in 13 and arthrodesis in five). Most commonly, an abductor pollicis longus tendon graft was used to add stability and interposition material (39%) with extensor carpi radialis longus, flexor carpi radialis, triceps, and semitendinosis also used depending on availability following the primary surgery. In terms of outcome measures, visual analogue scale (VAS) pain scores and the Disabilities of Arm, Shoulder and Hand (DASH) scores were completed by 25 patients with 27 operated hands. Follow-up in this group was 8.5 years (2 to 21); the mean VAS was 28.2 on a 100-point scale, and the mean DASH was 32.0. Unfortunately, there were no preoperative scores for comparison. Postoperative complications occurred in 20% and included mainly pin site infection/irritation and superficial radial nerve irritation, but also persistent pain, infection, sesamoiditis, and carpometacarpal joint instability. Patients with complications had significantly worse outcomes as measured by VAS for pain and DASH compared with those without complications. Overall, and not unsurprisingly, the results following revision surgery to the thumb base are worse than those following primary surgery. However, the range of movement achieved was described by the authors as comparable to primary surgery. They also reported seemingly better results with a ligament reconstruction using either abductor pollicis longus or extensor carpi radialis longus, although this could not confirmed statistically due to the small numbers, nor could potential reasons for this finding be explained. Interestingly, those patients who underwent concomitant surgery to the metacarpophalangeal joint appeared to have more favourable outcomes than those who did not. This paper provides a long follow-up of complex revision cases and demonstrates that half of patients undergoing revision thumb base surgery can expect reasonable results.

Ulnar shortening and nonunion

Surgical anatomy of the dorsal cutaneous branch of the ulnar nerve

We would like to draw 360 readers’ attention to a valuable anatomical paper that caught our eye this month. As the relentless wheel of evidence-based medicine continues to roll, fewer papers of this nature are grabbing the attention of the orthopaedic readership. However, for the occasional wrist surgeon, the ulnar side of the wrist can be confusing and somewhat daunting, and some succinct and appropriate anatomical help can be a godsend. We all know that the dorsal cutaneous branch of the ulnar nerve branches from the ulnar nerve proximal to the ulnar styloid, before exiting the deep forearm fascia and passing dorsally into the hand giving off multiple branches. However, injury to this nerve remains common, potentially occurring in up to 10% of surgeries around the ulnar styloid, and neuromas can be particularly troublesome for patients. A team from Bangkok (Thailand) have sought to improve our understanding of the anatomy in this area.⁴ Using 44 arms from 22 fresh cadavers with no history of forearm fracture or deformity, the authors mapped the course of the dorsal branch of the ulnar nerve and its branches in order to accurately establish the local anatomy. Measurements of local relationships were performed with the elbow flexed and the forearm in mid-rotation. The forearm length was also measured to allow a normalized ratio to be presented. The dorsal cutaneous branch of the ulnar nerve arose from the main nerve itself at approximately the junction between the third and fourth quarters of the length of the forearm. In the majority of limbs, the nerve crossed the equator between volar and dorsal distal to the ulnar styloid at a mean distance of 10 mm. However, the nerve crossed at a mean distance of 11.2 mm proximal to the styloid in four forearms, and it passed directly over the styloid in six forearms. For those nerves crossing the volar-dorsal plane distal to the styloid, at the level of the styloid it lay, on average, 5.6 mm volar. The authors use a Cartesian coordinate system to trace the courses of the nerve and demonstrate that the danger zones are usually palmar to the styloid, both proximally and distally. Iatrogenic injury to the nerve is not infrequent, but certainly avoidable, and this paper should aid localization and protection.

Scratch collapse test for carpal tunnel syndrome: a systematic review and meta-analysis

Despite the frequency of presentation, diagnosis, injection, and surgery for carpal tunnel syndrome, there still exists significant variation among surgeons regarding diagnosis and treatment. In the United Kingdom, the commissioning groups are starting to pay attention to treatment of carpal tunnel syndrome, both through injection and surgery. It is somewhat bemusing that, despite decades of study, we still struggle to agree on who has carpal tunnel syndrome, let alone who should receive each treatment. One of the newer contenders for diagnostic test of choice is the ‘Scratch Collapse Test’. There are three camps when considering the Scratch Collapse Test: for some it may be a completely new concept; for some it has become a key component in clinical assessment of peripheral nerve problems; and others maintain scepticism concerning its accuracy. The test itself involves applying a stimulus in the form of a scratch over the area of presumed nerve injury or compression; the patient then forcibly externally rotates their shoulders against resistance. A weakness in external rotation after the ‘scratch’ is thought to suggest injury or compression at that site. While theories exist concerning why this effect occurs, the exact physiology behind the test remains uncertain. A team from Ottowa (Canada) have performed and published a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant systematic review and meta-analysis to assess the role of the Scratch Collapse Test in carpal tunnel syndrome.⁵ A rigorous search yielded just 13 potentially suitable articles, from which just three were suitable for inclusion in the qualitative synthesis and meta-analysis. Data from 165 patients overall were included, and pooled results showed a sensitivity of 0.32 (95% confidence interval (CI) 0.24 to 0.41), specificity of 0.62 (95% CI 0.45 to 0.78), a positive likelihood ratio of 0.75 (95% CI 0.33 to 1.67), and a negative likelihood ratio of 1.03 (95% CI 0.61 to 1.74). A receiver operating characteristic curve constructed to establish the diagnostic accuracy of the test had an area under the curve of just 0.25, suggesting a low diagnostic accuracy. From this review, it would seem that the utility of the Scratch Collapse Test, certainly as far as the evidence is concerned, is dubious. Coupled with the poorly understood physiology that theoretically underpins the test, it is difficult to recommend it as a diagnostic measure.

Lunate subchondral cysts under the spotlight

Ulnar-sided wrist pain has a multitude of causes, only one of which is ulnocarpal impaction syndrome, described above as due to excessive loading on the ulnocarpal joint from abutment of the distal end of the ulna. There is no single benchmark diagnostic test, and a combination of physical examination and radiological findings are often employed, with subchondral cyst formation in the lunate bone purported to be of importance. Many cysts are, however, asymptomatic and so it is difficult to know exactly where we are with establishing the cause of ulnar-sided wrist pain. In this study from Seoul (South Korea), the authors set out to compare lunate cysts in symptomatic and asymptomatic individuals in an attempt to establish clinical relevance.⁶ Over a three-year period, 375 patients who had an MRI or CT scan for indications other than former wrist pain were analyzed and defined as an ‘asymptomatic’ group. The comparator group was a series of 33 patients diagnosed as suffering from ulnar impaction syndrome, and differences between the two were retrospectively analyzed and presented in this paper. Essentially, what we have here is a radiological diagnostic study with little in the way of clinical information. However, within these constraints, there are significantly more patients in the symptomatic group who had a lunate cyst visible on their imaging, with a prevalence of 57% compared with 10% in those who were asymptomatic. The symptomatic group were also found in this investigation to be significantly more likely to have cysts on the palmar side of the lunate, whereas in asymptomatic patients, dorsal lunate cysts were more frequent. Logistic regression demonstrated that both patient age and a diagnosis of ulnar impaction syndrome were a significant risk factor for the presence of a lunate cyst. Interestingly, however, neither positive ulnar variance nor duration of symptoms were predisposing factors for symptomatic individuals in this analysis. The nature of the relationship between symptomatic ulnar impaction syndrome and formation of lunate cysts is difficult to determine, and it does seem unlikely that this is a pathogenomic finding. Where present, their presence should therefore be interpreted as such.

Carpal tunnel release and new onset trigger finger

In the June 2018 issue of 360, we reported on the results of a systematic review on trigger finger following carpal tunnel decompression surgery. This showed an incidence of trigger finger of 8.5% within six months of surgery. In this issue, we report a single study of over 1000 patients in a single tertiary centre in Boston, Massachusetts (USA) that aims to answer the same question, albeit in a large retrospective cohort series rather than evidence synthesis.⁷ Over 1300 hands were retrospectively identified over a five-year period and, after exclusion of cases where carpal tunnel contralateral decompression surgery was performed in the first postoperative year, conditional logistic regression analysis was performed in 900 hands. The association between carpal tunnel syndrome and the development of trigger finger in the operative hand within the first 12 months was compared with that in the contralateral hand. The data from both hands was used to examine associations between carpal tunnel decompression and trigger finger in the year before surgery as compared with the year following. Multivariate regression was used to evaluate associated risk factors. A new trigger finger was seen in 10.6% of hands within one year before carpal tunnel decompression and 5.8% of hands within one year following carpal tunnel decompression. Furthermore, the incidence of trigger finger was 2.5 times higher in the operative hand when the postoperative year was compared with the preoperative year, while the contralateral hand was 0.5 times lower. With these results in mind, it therefore seems valid to say that there is an obvious predisposition for these pathologies to present in the same hand, and that there is likely to be a relationship in the presence of the pathologies. What the data from this series do not support, however, is the hypothesis that open carpal tunnel decompression is associated with an increased incidence of trigger finger in the operative hand. This study has the great advantage of considering background incidence but, in a retrospective study with uncertain fidelity of data and unknown loss to follow-up, it is difficult to be absolutely certain of the conclusions. It is certainly of interest for hand surgeons, patients, and healthcare funders who wish to get to the bottom of this apparent relationship. While the jury is still out in terms of causation, what is clear from the currently amassed evidence is that there is a relationship between the two, which needs to be explored more closely.

TFCC in the absence of instability?

Continuing our focus on ulnar-sided wrist pain in this edition of 360, we consider another pathology that is not always symptomatic, and for which the treatment choices are therefore in question. Triangular fibrocartilage complex (TFCC) tears can also cause ulnar-sided wrist pain but the natural course of the pathology is not well understood and, in common with other diseases with a potentially degenerative aetiology, such as rotator cuff tears, there is an increasing incidence of asymptomatic tears with age. It is well recognized that a TFCC repair should be considered in those with symptomatic distal radioulnar joint instability, but is this also the case in those without instability? This is a well-studied pathology in the literature and one of the difficulties is that the reported incidence of asymptomatic degenerative tears clouds the message. This group from Anyang (South Korea) have undertaken yet another single-centre retrospective study examining the TFCC.⁸ However, unlike previous studies, their three-year cohort of 117 patients reports on individuals with TFCC tears but no distal radioulnar joint (DRUJ) instability. Diagnosis of a symptomatic tear required for the purposes of this study required ulnar-sided wrist pain, identification of a tear on MRI or CT arthrograms, and a positive ulnar grind test or ulnocarpal stress test. Overall, 25 patients were excluded as they met criteria for surgical intervention and 19 patients were lost to follow-up before six months. A total of 72 wrists were included in the final report (42 men and 30 women) with a mean age of 40 years and an age range of 18 to 70 years. This group was followed for a minimum of six months (mean 16 months) and the reported visual analogue scale (VAS) pain score and patient-rated wrist evaluation (PRWE) were recorded at the initial visit as well as at one, two, three, and six months in addition to final follow-up. A PRWE score of less than 20 points was taken to indicate complete recovery, while more than 20 points was considered to be incomplete. Survival analysis and Cox regression modelling were used to estimate the time to recovery, as well as to evaluate the effects of age over 45 years, obesity, sex, dominant hand, traumatic tears, ulnar positive variance, and chronic symptoms over six months. Overall, 30% of cases had completely recovered at six months and 50% had at one year. It was not possible from the candidate risk factors to identify any risk factors that were significant. This may be the product of an insufficient sample size, but nevertheless the paper does illustrate the potential success of treating TFCC tears non-surgically in the first instance, and the authors recommend a minimum of six months nonoperative management in their conclusion. We would agree that further study to evaluate possible predictors of failure of nonoperative management would be useful, in order to identify those who will require surgery in due course.